Harvesting and POST-hARVEST HANDLING OF PINEAPPLE

Transcription

1 Harvesting and POST-hARVEST HANDLING OF PINEAPPLE Joy. P. P. and Rashida Rajuva.T.A., Pineapple Research Station (Kerala Agricultural University), Vazhakulam Muvattupuzha, Ernakulam, Kerala, Tel. & Fax: , Web: INTRODUCTION In agriculture, postharvest handling of fruit is the stage of fruit production immediately following harvest, including cooling, cleaning, sorting and packing. After the fruit is ready for harvest (Figure 1), from the instance it is separated from its parent plant, the fruit begins to deteriorate. Postharvest treatment largely determines final quality, whether a fruit or fruit product is sold for fresh consumption. It also covers storage and transportation and the intermediate processing of fruits into a form for increased storage. Ananas comosus is the botanical name of the fruit we call as the pineapple. Native to South America, it was named for its resemblance to a pine cone. The name pineapple in English comes from the similarity Fig.1 Pineapples ready for harvest of the fruit to a pine cone. Pineapple is a well-known fruit all over the world and within the tropical fruits it represents the largest processed volume, generating several kinds of products like canned and frozen pineapple (in slices and pieces) and juice (single strength and concentrate). Brazil is one of the largest growers of pineapple in the world, but is insignificant as industrial processor. The Asian producers focus on the total usage of pineapple, that is primarily fresh fruit combined with canning and juice production, where juice is basically a by-product. In South America, fresh fruit is also the main usage, but the canning industry is not well developed and juice is produced from the whole fruit. Pineapple juice concentrate is applied to produce ready-to-drink pineapple juice or nectar and as main constituent in blends for multi fruit juices, nectars and juice drinks. The reason for that is that pineapple juice is considered as cheap juice solids compared to other fruit juice concentrates available, and as the concentrate is relatively neutral, it fits very well for blending with other tropical and exotic fruit juices of higher added value. After the field, post-harvest processing is usually continued in a packing house. This can be a simple shed, providing shade and running water, or a large-scale, sophisticated, mechanized facility, with conveyor belts, automated sorting and packing stations, walk-in coolers and the like. In mechanized harvesting, processing may also begin as part of the actual harvest process, with initial cleaning and sorting performed by the harvesting machinery. Regardless of the scale of harvest, from domestic garden to industrialized farm, the basic principles of post-harvest handling for most fruits are the same; handle with care to avoid damage, cool immediately and maintain in cool conditions, and cull (remove damaged items). Postharvest physiology is the scientific study of the physiology of living plant tissues after they have been denied further nutrition by picking. It has direct applications to postharvest handling in establishing the storage and transport conditions that best prolong shelf life. An example of the importance of the field to post-harvest handling is the discovery that ripening of fruit can be delayed and thus their storage is prolonged by preventing fruit tissue respiration. The fundamental principles and mechanisms of respiration, leading to post-harvest

2 Harvesting and post-harvest handling of pineapple 2 storage techniques are cold storage, gaseous storage, and waxy skin coatings. Another wellknown example is the finding that ripening may be brought on by treatment with ethylene. VARIETIES The oval to cylindrical-shaped, compound fruit develops from many small fruits fused together. It is both juicy and fleshy with the stem serving as the fibrous core. The tough, waxy rind may be dark green, yellow, orange-yellow or reddish when the fruit is ripe. The flesh ranges from nearly white to yellow. In size the fruits are up to 30 cm long and weigh 0.5 to 4.5 kg or more. In international trade, the numerous pineapple cultivars are grouped in four main classes; 'Smooth Cayenne', 'Red Spanish', 'Queen', and 'Abacaxi', despite much variation in the types within each class. The main pineapple varieties grown in Kerala are shown in Figure 2. Fig. 2 Varieties of pineapple grown in Kerala Smooth Cayenne or Cayenne ('Maipuri', 'Kew', 'Sarawak', 'Esmeralda', 'Claire', 'Typhoon', 'Saint Michel') Smooth Cayenne is extensively cultivated in Hawaii, Philippines, Australia, South Africa, Puerto Rico, Kenya, Mexico, Cuba and Formosa. The ovoid medium-sized fruit (1.5 to 2.5 kg) of 'Smooth Cayenne' is held on a short and strong peduncle. It ripens progressively, turning yellow from the base to the top, which is reflected in a strong internal maturity gradient too. The flesh is firm, close-textured, juicy and with a pale-yellow to yellow colour at maturity. And average acid range lies between 0.5 and 1.0% and total soluble solids (TSS) between 12 and 16 Brix. The plant is a poor producer of shoots and slips. The production cycle is about 18 months, longer than most other cultivars. 'Smooth Cayenne' is sensitive to many known pests (fruit borers, mites, symphillids, nematodes) and diseases (mealybug wilt, fusariosis, fruitlet core rot, butt rot), and to internal browning. However, it is considered tolerant to Phytophthora sp. and resistant to fruit collapse, caused by Erwinia chrysanthemi Burkbolder. Mauritius Mauritius is recommended for commercial cultivation for table purposes and distant marketing, due to its shorter duration of one year, better fruit quality, keeping quality and transportability.

3 Harvesting and post-harvest handling of pineapple 3 Vazhakulam pineapple The Geographic Indication registered Vazhakulam pineapple locally known as Kannara belongs to Queen Cultivar (Mauritius) suited for table purpose. The average fruit weight is g. The fruit has a pleasant aroma, a slightly conical shape, fruit eyes deeply placed, fruit flesh is crisp and golden yellow in colour, juice is sweet with brix and its acidity is %. It is a good source of carotene, vitamins, minerals and energy. Amritha It is a hybrid between Kew and Ripley queen. It has spiny leaves and months duration. Fruit is cylindrical, tapering slightly from near base, weighing kg. Crown (whorl of leaves attached to the apical end of the fruit) is small weighing g; ratio of fruit weight to plant weight is medium. Fruit is green when unripe and uniformly yellow when ripe; fissure and eye corking absent, spirals are left oriented. Fruit is firm with mild external aroma, skin 6 mm thick, flesh firm, non-fibrous, crisp and pale yellow in colour with rich aroma. Taste is good with high total soluble salts and low acidity. MD-2 MD-2 is a hybrid pineapple originated in the breeding program of the now-defunct Pineapple Research Institute in Hawaii, which conducted research on behalf of Del Monte, Maui Land and Pineapple, and Dole. Two similar seedlings, numbered and 73-50, were found to have bright-gold, very sweet, low-acidity flesh, high resistance to parasites and internal rot, skin that turned amber when ripe and, best of all, the ability to survive cold storage for up to two weeks. The Pineapple Research Institute, Hawaii was dissolved in 1986 and its assets were divided between Del Monte and Maui Land and Pineapple. Del Monte took , which it dubbed MD-2, to its plantations in Costa Rica, found it to be well-suited to growing there, and launched it publicly in In 1997, Del Monte began marketing its Gold Extra Sweet pineapple, known internally as MD-2. Del Monte also began marketing 73-50, dubbed CO-2, as Del Monte Gold. MD-2 or Dinar pineapple is the standard for the international market because of its colour, flavour, shape, lifespan and ripeness. The commercial cultivation of MD-2 variety of pineapple was started in Central and South American countries during But at present it has occupied 50-55% of world market and 70-75% of European market in fresh pineapple. This is due to its excellent fruit qualities like high brix value (17 for ripe fruit), low acidity ( %), medium fruit size (1.5 to 2.0 kg), cylindrical shape with square shoulder, small core size, resistant to internal browning, very long shelf life (about 30 days) etc. The most important fruit qualities of MD-2 are its long shelf life and cylindrical shape. Instead of just 21 days for the normal varieties, it has 30 days of shelf life and is able to survive in cold storage for up to two weeks. By the 12th month, it can be plucked. MD-2 is resistant to internal browning, but susceptible to fruitlet core rot, and more sensitive to Phytophthora than Smooth Cayenne/Kew. MD-2 variety fetches a premium price than other varieties. Hence MD-2 will be the best variety that can be imported for cultivation in Kerala which will increase the export share of the pineapple produced in the state. IPR rules are not applicable to MD-2 variety as it is not a patented variety. MD-2 variety can be imported from Costa Rica, Ghana, Cuba, France etc. Pineapples are graded by degree of skin colouration, size (weight), absence of defects and disease, and uniformity of these characteristics before packing. Other characteristics include maturity, firmness, nice shape, flat eyes and well-cured broken stem. Pineapples are normally

4 Harvesting and post-harvest handling of pineapple 4 packed into cartons of two different sizes and on the basis of colour and size a large telescoping fibre board carton holding 18 kg and containing 8 to 10 fruits in two layers, flat or upright, for surface and air shipment and a smaller container of 9 kg with five to six fruit in a single layer laid flat for air shipping. Tourist packs of two to four fruits are also prepared. Absorbent pads are used at the bottom of the carton and between layers, if fruits are placed horizontally within the carton. In other packs, fruits are placed vertically. FRUIT MATURITY INDICES Pineapple fruit should be harvested when it is firm and mature. Pineapples do not improve in eating quality after harvest. Sugar content does not increase after harvest. Therefore, the fruit must be picked at the optimum maturity and ripeness stage to suit the intended market. Pineapples are judged mature when they have reached full size and a nice yellow colour, depending on variety. There is no single fool proof indicator of pineapple fruit maturity. However, several external and internal fruit characteristics can be used in combination as indices to determine harvest maturity (Figure 3). The external indices include fruit surface colour (in most cultivars), the extent of fruitlet (eye) flatness, and fruit size. The internal indices include percentage soluble solids (i.e. sugar content) and appearance. The amount of fruit surface yellowing may be used as a guide for determining when to harvest in certain cultivars. Generally, the more yellow the surface area (less chlorophyll), the more mature and ripe the fruit. The natural progression of surface colour change during pineapple fruit maturation is from green to yellow to reddishbrown. If the fruit is allowed to remain on the plant until the full yellow stage it will have a flatter, less desirable flavour due to excess sugar content coupled with decreased acidity. The fruit will also be more susceptible to bruise damage at the full yellow stage. At very advanced stages of over-maturity, the surface colour of the fruit changes to reddish-brown. Once the fruit has been harvested, the change in surface colour and amount of yellowing should not be used as an indicator of fruit ripeness, since postharvest colour changes are not correlated with eating quality. Colour stages are categorised as follows. CS1: all eyes green, no traces of yellow; CS2: 5 to 20% of the eyes yellow; CS3: 20 to 40% of the eyes yellow; CS4: 40 to 80% of the eyes yellow; CS5: 90% of eyes yellow, 5 to 20% reddish brown; CS6: 20 to 100% of eyes reddish brown. The pineapple is a compound fruit comprised of numerous individual fruitlets. The fruitlets mature progressively from the bottom part of the fruit to the top. As the fruitlets mature, they become flatter. The extent of fruitlet flatness is usually a good indicator of overall fruit maturity. The bottom fruitlets are much flatter (and riper) than the top ones. Fruit which is ready for harvest should reach the appropriate size indicative of the cultivar. This is largely

5 Harvesting and post-harvest handling of pineapple 5 based on previous growing experience. However, individual fruit size by itself is not a reliable index of harvest maturity. It should be used in addition to surface colour and fruitlet flatness. Fruit maturity is highly correlated with soluble solids content. Pineapple fruit should have a minimum of 12% soluble solids near the base and 10% near the top. This is determined by taking two cross sections of the fruit; one at the point of its largest diameter near the base and Fig. 3a Maturity indices or ripening stages of pineapple followed in different countries Fig. 3b Maturity indices or visual ripening stages of pineapple followed in different countries another in the upper third portion of the fruit, and squeezing a few drops of juice from each cross section onto the prism of a hand-held refractometer. However, this is a destructive test of harvest maturity. It is used mostly in large-scale operations where sacrificing fruit of different sizes is acceptable in order to determine the correlation between fruit size and maturity. The internal appearance of the flesh is also indicative of fruit maturity. Random samples of fruit should be sliced horizontally at the point of the largest diameter. Immature fruit has a white flesh colour, while mature or ripe fruit has a yellowish-white flesh. The flesh also becomes slightly translucent in appearance at maturity. Fruits are over mature when more than half of the cross-sectional area of the fruit is translucent. The conical-shaped biotype of Montserrat develops flesh translucency sooner than the cylindrical biotype.

6 Harvesting and post-harvest handling of pineapple 6 QUALITY INDICES Uniformity of size and shape Firmness Freedom from decay Freedom from sunburn, sunscald, cracks, bruising, internal breakdown, endogenous brown spot, gummosis, and insect damage Tops (crown leaves)- green colour, medium length, and straightness Range of soluble solids %; titratable acidity (mainly Ascorbic acid) %; and ascorbic acid mg/100 g fresh weight, depending on cultivar and ripeness stage HARVESTING Based on a number of research works a specific terminology for development, maturation, definition of the edible stage and senescence for pineapple was proposed. This proposal was based on physical and biochemical changes that take place during propagation and development of the fruit. There is a time span of 110 days between the end of flowering and the point at which the fruit is at its edible stage. Changes in chemical composition occur when half of the peel turns yellow. Chlorophyll, carotenes, xanthophiles and anthocyanines are the main pigments found in pineapple. Their presence changes the external colour of the fruit from green, green-yellow, or yellow, to a mixture of yellow and purple with or without green. External colour of pineapple is an important trait in consumer preference. During maturation chlorophyll fades out and total and pulp carotenes increase, while peel carotenes decrease. Both peel and pulp carotenes rise at senescence. These changes define four stages in fruit development. Changes in maturation stage are evident when peel colour turns from green to yellow at the base of the fruit. Pineapple is a non-climacteric fruit and can be harvested as soon as it is ready for consumption. A minimal content of soluble solids of 12% and a maximal acidity of 1% insure a minimal level of consumer acceptance along with size and texture uniformity, absence of rotting, sunburns cracks, bruises, internal breakdown endogenous brown spot, gummosis or damage by insects. Crown leaves should be green, medium in length and erect. Soluble solids must fall between 11 and 18%, titratable acidity as citric acid from 0.5 to 1.6%, ascorbic acid should fall between 20 and 65 mg/100g of fresh weight, depending on the cultivar and stage of maturity. Pineapple fruit can be classified in three categories, category A, defined by fruits weighing more than 1.5 kg; category B, fruits weighing between 1 and 1.5 kg; and category C, fruits weighing less than 1 kg. Harvest maturity is usually based on skin colour and the shape of the individual fruitlets. Colour is not an infallible means of measurement since Smooth Cayenne can be fully mature with yellow sweet flesh while the skin is still green. This has presented a problem in marketing such fruits in Europe and in some cases they have been labelled to indicate they are ripe while the skin is green. Skin colour can vary due to season, rainfall, micro-climate and field practices. In other cases estimation of the skin colour can be effective. The eyes turn from green to yellow orange from the bottom and maturity can be judged on the number of rows of eyes that have changed colour. A common harvest maturity is when two or three rows have changed colour. In Hawaii, skin colour is supplemented by a minimum reading of 12 Brix for fruit destined for fresh consumption. Harvest maturity can also be estimated by relating it to the time after flowering or mid-flowering, but the number of days may vary from place to place. In Madagascar the

7 Harvesting and post-harvest handling of pineapple 7 period from flower induction to ripening varied from days and in South Africa from days. For Smooth Cayenne in Hawaii, it took 110 days from the completion of flowering to harvest maturity, but it was between days, that is, from mid-flowering to the onset of ripening. These variations were attributed to seasonal temperature variations. In Queensland in winter, pineapples are picked at an immature stage to avoid black heart, and this stage is preferable for handling owing to high resistance to bruising. Half ripe (50% of the shell yellowing) Smooth Cayenne fruit can be held for about 2 weeks at 7.5 C and still have about 1 week of shelf life, and at this stage the fruit was suitable for export. Quarter yellow (25% yellowing) pineapples at harvest gain about one additional week s storage for every 6 C decrease in storage temperature (no temperature range was reported) and at 7 C the maximum storage life is 4 weeks. The sound of a fruit as it is tapped sharply with the knuckle of the finger can change during maturation and ripening. Consumers sometimes use the method of testing fruit. This method may only be used postharvest to determine their maturity since the plants are so spiky that it would be very difficult to get at the fruit. Kew pineapple plants flower months after planting and attain harvesting stage months after planting, depending on the variety, time of planting, the type and size of plant material used and the prevailing temperature during fruit development. Under natural conditions, pineapple comes to harvest during May- August. With a slight colour change at the base of developing fruit, it could be harvested for canning purpose. But for table purpose, the fruit could be retained till it develops satisfactory golden yellow colour. Harvesting is done with a sharp knife, severing the fruit-stalk with a clean cut retaining 5-7 cm of stalk with the fruit in such a way that the fruit is not damaged. The stage of maturity at harvest is dependent on the required storage or shelf-life and the method of transportation to the export markets. The level of yellow colouration of the "eyes" of the fruit judges maturity. The harvest operation is done using special devices to draw the fruit from the field by breaking the fruit that shows proper maturity stage and placing them at the edge of the field where they are manually sorted by size. The fruit is carried in trucks placing the crowns downwards for cushioning. From 50 to 80 dozens may be transported, depending on the size. Fruits are marketed by the dozen; those intended for industrial processing are placed in crates at the edge of the parcel and the crowns are chopped off, after which they are transported in bulk in larger trucks to the processing plant. Fruit for export markets use different systems, depending on the buyer. Some buyers require green fruit which means soft green colour near the peduncle, with 12 Bx, porosity of 1.5 and translucency 0 to 0.5. Other buyers demand ripened or off-green fruit with a minimum of 12 Bx, porosity of 1.5 and translucency of 1 to 1.5. Ethephon is applied at 1.5 ml/l (1 ounce in 20 litres) of water, sprayed on the fruit one week prior to the harvest. When colour turns golden yellow fruits are harvested with care to avoid mechanical damage. Fruits are carried to a truck with 5 cm of polyfoam in the bottom and 2.2 cm on the sides. From 3 to 5 layers of pineapples are placed crowns facing downwards to avoid damage. Another way to harvest is using a mechanical harvester which may cut the process time to one fourth and produces minimal damage to the fruit by handling. Sugar content should be assessed in the field prior to harvesting to ensure adequate sugar development. A minimum of 10% is generally required although. This may vary with the market. Sugar content is not always related to the colour stage as agronomic and production factors will affect sugar development. For the export market where sea-shipment for seven to

8 Harvesting and post-harvest handling of pineapple 8 fourteen days is used, fruits should be harvested at CS 1, where the fruits show no yellow colour development on the eyes. Those harvested at more advanced stages are more susceptible to mechanical damage and over-ripeness. Fruit maturity can also be assessed on random samples by determination of the flesh condition. This is carried out by slicing the fruit horizontally at the point of largest diameter; in fruit for sea-shipment export; the fruit should show limited development of translucent areas. Where more than half of the area is translucent, the fruit is considered beyond optimum maturity. Pineapples harvested by hand are snapped from the stalk using a downward motion. The fruit should be placed in field crates and while in the field, left in shaded conditions. Collection in the field and field to pack house transport using sacks or bags will cause mechanical damage and increase the level of rejection. On arrival at the packing facility, the stems and the crowns should be trimmed to 2 cm (0.5") and 10 cm (4") respectively. Out grading should be made of all fruits which are undersize, oversize, over-ripe, under-ripe (depending on the market requirements), damaged, bruised or show fungal or insect damage. Pineapple is a perennial fruit crop and the returns continue, usually, for a period of 3 years in case of variety Mauritius. Under natural conditions, pineapple comes to harvest during May- August. With the application of Ethephon and fertilizers the first yield is obtained within months. Pineapple plants flower 7-8 months after planting and attain harvesting stage in a year, depending on the variety, time of planting, the type and size of plant material used and the prevailing temperature during fruit development. Observing the colour change is the most common method of determining the maturity of fruits. For long distance transportation, fully mature fruits in green itself just before colour change are harvested. With a slight colour change at the base of developing fruit, it could be harvested for canning purpose. But for table purpose, the fruit could be retained till it develops satisfactory uniform golden yellow colour. Harvesting is done with a sharp knife, severing the fruit-stalk with a clean cut retaining 5-7cm of stalk with the fruit in such a way that the fruit is not damaged (Figures 4 and 5). Fruits are stacked in piles or on to the vehicles with the crown facing down. Fruits for fresh fruit market are often marketed with crowns. The yield of pineapple fruit varies with the variety, agro-climate, agro-techniques and planting density. The fruit yield with a plant density of plants/ha is about t, plants/ha about t and that of 43, plants/ha is t/year, with the yield decreasing progressively from first year to third year which is the normal economic life span of Mauritius pineapple. Domestically marketed fruits should be harvested close to full ripeness, which in the case of the cultivar is at the one-half yellow external surface colour. Fruit is near its maximum mass at this colour stage if still on the plant. Fruit intended for the export market should be picked slightly sooner, at the quarter-yellow colour stage. It will also be necessary to expeditiously move the product from the field to the packing area to the airport as soon as possible and use a strong package coupled with air conditioned temperature storage. Fruits picked mature but prior to full ripeness (less than one quarter yellow) will be firmer and better able to tolerate long distance transport. They will have a less desirable flavour. Without refrigeration or rapid transport to market, it will be necessary to sacrifice some flavour for adequate firmness in order to have the potential to export the fruit. Pineapples harvested when immature will not ripen and will have a low sugar content and poor flavour. On the other hand, fruit harvested over mature will get soft and bruise easily during transport and will have a very short market life (Figure 6). Pineapples are harvested by hand, with the pickers being instructed as to the stage of maturity required. The fruit should be broken off the stalk with a downward motion, or cut with a knife

9 Harvesting and post-harvest handling of pineapple 9 slightly below the base of the fruit. A large canvas picking sack or bamboo basket strapped over the shoulders is commonly used as a harvest-aid in many parts of the world (Figures 7 and 8). Up to 6 fruits can be put in the sack, which is able to be opened from the bottom to allow the fruit to be transferred to a larger field container or padded wagon. The fruit may also be harvested in wooden or plastic field crates. Mechanical harvesting is now popular (Figure 9). Pineapples meant for export are cut with a knife to leave a sizeable stalk. The stalk is used for holding the fruit during movement from the field; while those for the local market are simply broken off. In addition, the products for the local market get no pre-treatment prior to marketing. Those for export purposes are, brushed before parking and are trimmed to leave a stock of 2.5 cm. Grading for local markets takes place at the retailers. Those for export are graded according to colour and size; and normally pineapples of kg weight are exported. The export produce are directly packed into cartons and transported by trucks or pickups. Produce destined for the local market is put on pickups or lorries and the loading and offloading is done manually. Fig. 4 Pineapple harvesting guidelines Fig. 5. Manual pineapple harvesting Fig. 6. Over mature pineapple not fit for export Fig.7 Canvas sacks used for harvesting pineapple Fig.8 Bamboo baskets used for harvesting pineapple

10 Harvesting and post-harvest handling of pineapple 10 Fig. 9 Mechanical harvesting of pineapple practiced in different countries Pineapples should feel heavy for their size; otherwise they could end up dry and tasteless. They should look, feel and smell clean and have no bad or mouldy marks on the outer surface. As pineapple stops ripening when picked, choose carefully and don't select one that looks immature. Pineapples can be stored at room temperature however they spoil easily and should be watched carefully. To keep it longer than a day or two, wrap in a plastic bag and store in the fridge for up to five days. If pineapples are cut, store unused pieces in the fridge in an airtight container and use as soon as possible. They can be frozen, however this will change the flavour. The two components of quality that may change after harvest are external colour and texture of the flesh. Pineapple fruit typically changes from a green to yellow-orange colour during storage. In addition, the texture of the flesh softens with time. The crown should be left intact and protected from damage. Consumers associate crown freshness and condition with fruit quality. The practice of crown removal by some vendors in the domestic market is not recommended. This leads to microbial decay of the wounded area and a rapid rate of deterioration. The fruit appearance is less appealing without the crown. When the fruit is one-third or more yellow, it can be harvested. Refrigerating an unripe pineapple can ruin the fruit. To harvest the pineapple, simply cut it from the plant with a sharp kitchen knife where the pineapple joins the stalk. Then either leave it to further ripen at room temperature if need be, refrigerate the fruit if completely ripe or, ideally, devour immediately. Preliminary grading of the fruit according to size, condition and maturity should be done at this time. The fruit should then be transported as soon as possible to a shaded collection area or packing facility. The commonly available plastic or nylon sacks should not be used for transport, as they will cause significant amounts of mechanical damage to Fig.10 Harvested fruits protected from sun

11 Harvesting and post-harvest handling of pineapple 11 the fruit. Avoid exposing the fruit to the direct sun in order to prevent softening and possible sunburn (Figure 10). Fruit stacked in piles at collection sites should be transported as soon as possible to shaded packing facilities. Fruit bruising is a major problem during harvesting and packing. A fruit drop of 30 cm can result in serious damage, which typically appears as discoloured, slightly straw-coloured flesh. After harvesting, the fruits are graded according to size, shape, maturity, and freedom from diseases and blemishes. The cut surface is treated with a suitable fungicide to control fungal decay. GRADING In pineapple, grading is done mainly based on the fruit weight or size. Generally, there are five classes as detailed below (Figure 11). In some areas, the grading is limited to three classes as A (> 1000 g), B ( g) and C (< 500 g) with minor variation depending on the region. Class Weight (g) A above 1500 B C D Baby Less than 550 Grade criteria Mauritius grades Fig. 11 Grading in pineapple MD-2 grades PREPARATION FOR MARKET Today, pineapple consumers not only consider the physical appearance of the fruit to make a purchasing decision and such process has become more complex. In addition to physical appearance, other qualities are considered including colour, sweetness, aroma, fruit uniformity, size and country of origin or brand name. The proper time for harvest depends on its end use. Fruits for export should be cut when the fruit is completely developed but green. Pineapples for domestic market are cut mature but not fully ripened. Harvest is made manually; the fruit is torn to tear it from the peduncle. For transport, fruits are placed on leaves or a sawdust bed alternated with crowns, to decrease mechanical damage. It is not advised to pile up too many layers of fruit. Harvested fruits are placed in trucks or wagons crown side down and up to 3 layers high. It is important to avoid fruit overheating either in the field as well as during transport and handling. Fruits are taken to the packing plant and then washed and coated with a mixture of a fungicide and a liquid wax. For international markets pineapple is classified as: US Select (10 fruits of 1.4 to 1.8 kg), No. 1 (8 fruits of 1.81 to 2.0 kg) and No. 2 (6 fruits of 2.01 to 2.5 kg). Packing for export markets is a one-piece box made of telescopic fibre capable of holding 9 kg or 18 kg. In order to get better fruit strength during transport and prevent damages, pineapples with 1/4 ripening (yellow colour at the base of the fruit covering 25% of the surface) are selected.

12 Harvesting and post-harvest handling of pineapple 12 Transport temperature and relative humidity should be 7 to 13 C and 85 to 90%, respectively. Chilling injury may occur below 7 C. Pineapples for export must meet the following requirements; uniform size and shape, proper firmness, free of rotting, sunburns, cracks, bruises, internal breakdown, endogenous brown spot, gummosis and damages caused by insects. Crown leaves should be green, medium length and erect. Soluble solids must fall between 11 and 18%, titratable acidity as citric acid from 0.5 to 1.6%, Ascorbic acid should fall between 20 and 65 mg/100 g of fresh weight, depending on the cultivar and stage of maturity. Waxing can be applied to modify internal O 2 and CO 2 contents of the fruit in such a way to reduce the occurrence and severity of endogenous brown spot. Sea transportation is the main form of handling pineapple for international trade of fruits and vegetables. It is the most economical and specialized means for handling large amounts of fresh produce. Depending on the volume, it can be done in refrigerated ships (reefers) or in containers equipped with cooling systems. Reefers are usually large capacity vessels (over 4,000 tons) and are equipped with efficient air circulation systems with control of air velocity and exchange. Loading is made through side scuttles or by continuous conveyors installed from the pier to the cargo warehouses. The Reefers are specialized forms of transport for fruits and vegetables, they have built in good thermal insulation and ducts designed for cold air circulation, as supplied by the refrigeration system or with independent cooling system connected to the electrical network. There are also refrigerated containers with controlled atmospheres, which can adjust levels of O 2, CO 2, relative humidity and temperature. Refrigerated containers are built with standard dimensions; 8 x 8 feet wide, and either 10, 20, 30 or 40 feet long. The most common containers are those with 40 feet long, and then those with pies 20 feet long. Pre-harvest ethylene treatment Ethrel (Ethephon), has been used as a source of ethylene for decades and it is used to initiate flowering in pineapples. It has also been applied just before harvesting to accelerate degreening and therefore the development of the orange colour in the skin. In Queensland, Smooth Cayenne pineapples treated prior to harvest with Ethrel, at a concentration of 2.5 l in 1000 l of water, had superior eating quality, degreened more evenly, but had a shorter shelf-life due to accelerated skin senescence than untreated fruit 10 days after harvest. Treated fruit left on the plant for 23 days had inferior eating quality to the untreated fruit. These effects are due to the effect of the ethylene speeding up the maturation of the fruit. Cleaning Pineapple fruits are quite perishable and should ideally be packed for market within a day of harvest. The initial step in preparation for market involves cleaning of the outside of the fruit (Figure 12). For the domestic market, this generally involves trimming of the stem at the base of the fruit to a length of 1-2 cm, removing any damaged or unsightly leaves in the crown, and a gentle dry brushing of the fruit surface to remove dirt and dust. A similar protocol should be followed for the export market, with more emphasis placed on fruit uniformity and quality. Depending on the Fig.12 Washing pineapples in water

13 Harvesting and post-harvest handling of pineapple 13 export market requirements, all fruits which are undersized, oversized, over ripe, under-ripe, damaged, bruised, or show fungal or insect damage should be discarded. The stem must be trimmed very close to the base and the crown has to be cut back to a length of 10 cm. Then the fruit has to be washed in a soap solution and thoroughly scrubbed on the outside with a brush to remove all live insects. The wash water should be properly chlorinated (150 ppm free chlorine) and maintained at a ph of between 6.5 to 7.0. In addition, an approved postharvest fungicide should be added to the wash solution to reduce decay. Bayleton and benomyl are two postharvest fungicides commonly used. After washing, the fruit must be dried and inspected by a trained and certified inspector. Fruit approved for export by the inspector can then be packed. Waxing For maximum potential shelf life, pineapple fruit should be waxed after cleaning and drying. Several types of food-grade waxes are appropriate for pineapples, and they can be applied by dipping or spraying. The most commonly used waxes for pineapples are mixtures of carnauba and paraffin or polyethylene and paraffin. The type of wax chosen must be approved by the importing country, if the market destination is for export. The wax should be applied only to the fruit surface and not the crown, as many waxes cause injury to the crown. Beneficial effects of waxing include a reduction in fruit internal browning, less moisture loss, and a shinier external appearance. Sorting Regardless of the market destination, the fruit should be sorted according to size, shape, firmness, external colour, insect damage, and decay. Visibly damaged fruit should be rejected. Different markets have different quality requirements and the fruit should be graded to conform to the individual market standards. However, there are certain minimal requirements for pineapple fruit intended for any market. The fruit should: be clean and free of dirt or stains be mature and firm be well shaped and have fully developed eyes (fruitlets) be free of punctures, wounds, and cuts be free of sunburn, insect damage and decay have a well cured butt have a single crown Packing All fruits packed in the same carton or container should be uniform in size, shape, and external colour. Immature or over mature fruit should not be packed for export. It is important that the carton be properly ventilated and be of sufficient strength to withstand the rigors of distribution without collapsing. Weak cartons do not have sufficient physical strength to be stacked and result in major losses of the fruit upon arrival in the destination market. A carton with enough bursting strength should be used to avoid damage to the product during transport Fig. 13 Typical corrugated fibre board carton used for exporting

14 Harvesting and post-harvest handling of pineapple 14 and handling. A commonly used package in the international trade of pineapples is a fulltelescopic two-piece corrugated fibre board carton (Figure 13). Top and bottom ventilation, in addition to side vents are required, particularly where sea shipments are used. Typical carton inside dimensions are 30.5 cm wide x 45 cm long x 31 cm deep. The preferred method of packing is to place the fruit vertically on the base, and then to place dividers between the fruits to prevent rubbing and movement. With some cartons, this is not possible and fruits are laid horizontally in alternating directions; where two layers of fruits are packed, a divider is required between the layers. Another commonly used export carton for pineapples is a single-layer corrugated fibre board carton (Figure 14). It is important the carton be properly ventilated and be of sufficient strength to withstand the rigors of distribution without collapsing. Weak cartons do not have sufficient physical strength to be stacked and result in major losses of the fruit upon arrival in the destination market. STORAGE CONDITIONS Fig.14 Single-layer corrugated fibre board carton used for exporting pineapples Temperature For maximum postharvest life, pineapple fruit should be cooled to 8 C as soon as possible after harvest and maintained at this temperature during transport to market. At this temperature, pineapples harvested at the quarter-yellow stage have a shelf life of approximately 3 weeks. Storage at higher temperatures will result in reduced shelf life, to as short as only a few days at ambient temperature (30-32 C). Fruits that are quarter yellow at harvest, gain about four additional days of shelf life for every 6 C decrease in storage temperature from 32 to 8 C. On the other hand, pineapple fruits are subject to low temperature breakdown, also known as chilling injury, and should not be stored below 8 C. Sensitivity to chilling injury is related to the ripeness stage of the fruit, with mature green fruit being more susceptible. Internal tissue darkening and postharvest decay are typical symptoms of chilling injury. Pineapples harvested at more advanced stages of ripeness will have short market life. For example, fruit harvested at the half-yellow colour stage will have about 10 days of storage life at 8 C followed by an additional week of market life. Relative Humidity Pineapple fruits are susceptible to wilting, shrinking and shrivelling in low relative humidity (RH) storage environments. Most of the weight loss occurs through the leaves of the crown. The rate of transpiration and water loss from the fruit becomes increasingly greater with decreasing RH. Ideally, pineapples should be held at 90 to 95% RH. Transport Fruit should be transported carefully to market in order to minimize bruise damage and subsequent postharvest decay. Use of strong protective packaging will help to minimize bruise damage. Proper loading and stacking of the cartons in the bed of the transport vehicle is essential to protect the product. Sufficient air circulation through the sides of the cartons is necessary to avoid product re-warming during transport. The pineapple cartons should be covered and never exposed to direct sunlight during transport. This will accelerate the rate of

15 Harvesting and post-harvest handling of pineapple 15 ripening and softening of the fruit, in addition to possible sunburn damage. In the absence of refrigeration, the fruit should be transported during the cooler part of the day. POSTHARVEST DISEASES Pineapples are susceptible to a number of postharvest diseases. Decay is significantly higher in mechanically injured fruit, when poor sanitation practices are followed, or if postharvest cooling is not provided. The fused nature of the fruitlets means that the flesh of the fruit is not sterile and contains yeasts and bacteria. The most common diseases are black rot, fruitlet core rot, and yeasty fermentation. Black Rot Black rot, caused by the fungus Thielaviopsis paradoxa, is typically the most common and severe postharvest disease of pineapple. It is also referred to as stem end rot, water blister, or soft rot and is characterized by a soft watery rot of the flesh. The severity of this disease depends on the amount of fruit bruising or wounding incurred during harvest and packing, the level of inoculum on the fruit, and the postharvest temperature. There is also a strong correlation between rainfall duration prior to harvest and postharvest incidence of this disease. Black rot does not occur in the field unless the fruit is overripe or injured. Black rot usually starts at the point of detachment of the fruit (stem end), although it can readily infect bruised or other damaged areas of the fruit. Infection occurs 8 to 12 hours after wounding and symptoms begin as a soft, watery rot which later darkens due to growth of the dark-coloured fungal mycelium and spores (Figure 15). Fungal growth is rapid at temperatures between C. Control of black rot is achieved by minimizing mechanical injury to the fruit coupled with appropriate postharvest sanitation (150 ppm chlorine wash plus fungicide treatment). The most effective postharvest fungicides for controlling black rot are thiabendazole, benomyl, and captan. For effective control, the fruit must be dipped in the fungicide within 6 hours after harvest. Storage of the fruit at 7 C is also necessary to inhibit growth of the fungus. Fruitlet Core Rot Fruitlet core rot is a postharvest fungal disease-yeast-mite complex of pineapples caused by the fungi Penicillium funiculosum, Fusarium moniliforme var. subglutinas, the round yeast Candida Guilliermondi, the fruit mite Steneotarsonemus, and the red mite Dolichotetranychus floridanus. This disease complex is also called black spot or fruitlet brown rot. Symptoms appear as brown to black coloured areas in the centre part of individual fruitlets (Figure 16). The principal means of reducing the incidence of fruitlet core rot is by spraying the crop with an acaricide to control the mites which spread the disease. Yeasty Fermentation Fig.15 Black rot Fig.16 Fruitlet core rot Pineapple fruits are not sterile inside and contain many non-growing, but viable yeasts and bacteria. In damaged, overripe, and inter-fruitlet cracked fruit, existing yeasts may start to grow

16 Harvesting and post-harvest handling of pineapple 16 or new yeasts may invade. The yeast Saccharomyces is most often responsible for fermentation. Symptoms include fermentation, with bubbles of gas and juice escaping through cracks in the skin. The skin eventually turns brown and leathery and the internal flesh becomes spongy with a bright yellow flesh (Figure 17). Control Strategies Careful handling to minimize mechanical injuries Prompt cooling and maintenance of optimum temperature and relative humidity throughout Post-harvest handling and treatments Application of fungicides, such as thiabendazole (TBZ) Fig.17 Yeasty fermentation POSTHARVEST INSECTS Mealy bugs are typically the worst postharvest insect problems of pineapples. They invade the fruit prior to harvest and hide in crevices between fruitlets, underneath the crown leaves, or inside the whorl of the crown (Figure 18). They can be significantly reduced in population by pre-harvest insecticide sprays and ant control. After harvest, they need to be removed by brushing the fruit. POSTHARVEST DISORDERS Sunburn Localized sunburn of the fruit surface can be a problem on fruit left exposed to full sun after harvest. The affected areas of the fruit surface show a bleached yellow-white skin, with damage to the underlying flesh (Figure 19). The damaged tissue is more susceptible to postharvest decay. Sunburn can be avoided by putting the fruit in a shaded area after harvest. Chilling Injury Fig.18 Mealy bug infested fruit Fig.19 Pineapple sunburn Chilling injury (CI) occurs in pineapple fruit stored below 7 C. External symptoms of CI include wilting and discolouration of the crown leaves, failure of green-shelled fruit to yellow, browning and dulling of yellow fruit, surface pitting of the fruitlets which eventually coalesce into larger sunken lesions, and postharvest decay. Internal symptoms of CI include flesh browning or darkening, tissue softening, and off-flavour development (Figure 20). CI becomes more severe with decreasing storage temperatures and increasing lengths of exposure to chilling temperatures. Also, immature fruits are more susceptible to CI than mature fruit. (Full-green colour stage pineapple may suffer CI at 10 C). Although the tissue damage from CI in quarter-yellow colour stage fruit only occurs at temperatures below 7 C, development of the Fig.20 Pineapple chilling injury symptoms occurs within several days at ambient temperature following removal from cold storage. Postharvest waxing of the fruit minimizes CI symptom development.

17 Harvesting and post-harvest handling of pineapple 17 Internal Browning Internal browning is a common postharvest physiological disorder affecting pineapples. It is more pronounced in those cultivars like Smooth Cayenne that have low ascorbic acid content. It is more severe in those fruits exposed to cool night temperatures followed by high day temperatures prior to harvest. Storage of the fruit below 7 C also accentuates internal browning. Symptoms begin as small greyish translucent areas at the base of the fruit near the core. These areas eventually darken and in severe cases the entire internal flesh turns brown to black in colour (Figure 21). Control of internal browning may be Fig.21 Pineapple internal browning obtained by waxing the fruit. Flesh Translucency Flesh translucency is a physiological disorder in which the internal flesh becomes shiny and translucent in appearance. Translucency ratings are followed to indicate the intensity (Figure 22). It is more common in less mature harvested fruit. Translucency begins before harvest and continues during storage. It is generally more common in fruits with small crowns. Waxing can reduce the rate of translucency development after harvest. Translucent fruits are more susceptible to mechanical injury, which leads to intracellular sap leakage and loss of marketable fruit. Fig.22 Pineapple translucency rating 0-6 PRINCIPLES AND METHODS OF PRESERVATION OF PINEAPPLE PRESERVATION Preservation is the protection of foods against spoilage. It may be defined as the set of treatment processes that are performed to prolong the life of foods and at the same time retain the features that determine their quality, like colour, texture, flavour and especially nutritional value (Figure 23). Food preservation processes have different time scales, ranging from short periods needed for home cooking and cold storage methods, to much longer periods of time required Fig. 23. Perishability and shelf life of fruits and vegetables

18 Harvesting and post-harvest handling of pineapple 18 by strictly controlled industrial procedures such as canning, freezing and dehydration. The preservation of fruits and vegetables entails the partial utilization of the raw material. In some cases, during the process it becomes necessary to add a packing medium, e.g., syrup or brine, while in others the raw material is used alone, as in frozen products. The raw material may be processed differently, depending upon the product to be obtained, e.g. vegetables in sauce, jellies, pickles and juices. The same raw material may be processed in different ways, as a result of which different products will be manufactured. In general terms, some preservation methods are mentioned as below. Refrigeration Cold storage with modified atmosphere Superficial chemical treatments Special storage condition Packaging systems involving modifications in atmosphere Canning Freezing Dehydration Preservation methods by chemical action Objectives of preservation To increase shelf life of food for increasing the supply To make the seasonal fruits available throughout the year To add variety to the diet To save time by reducing preparation time and energy by fire To stabilize the prices of the food in the market To improve the health of the population METHODS OF PRESERVATION Acids, salts and sugars are the principal food preservatives of chemical nature. Sodium chloride (salt) is perhaps the oldest compound serving as a preservative. Acetic acid in the form of vinegar is used in the manufacture of several pickled products. Benzoic acid, sodium salts - sodium propionate, di acetate and sulphur dioxide, and sodium chloride are added to foods to prevent spoilage. Sugars are employed in the manufacture of jelly, jams, preserves, sweetened condensed milk, sweet pickles and other products aiding the preservation of the products into which they are incorporated. Preservation by sugar Sugar is generally added in the processing of jams, jellies and sweets. The fruit must be boiled, after which the sugar is added in variable amounts, depending upon the kind of fruit and the product being prepared. The mixture must then continue to boil until it reaches a high level of soluble solids, which allows for its preservation. The addition of sugar combines with certain fruit substances to produce a gel like consistency, which characterizes the texture of jams and jellies. To achieve this, appropriate acidity levels and sugar content, together with pectin must be used, form a proper gel.

19 Harvesting and post-harvest handling of pineapple 19 Preservation by benzoic acid and benzoate Benzoic acid is a stable, white, granular or crystalline powder possessing a sweet, stringent taste. The sodium salt is more soluble in water (62.5 g in 100 ml) at 25 C than benzoic acid. For this reason it is the preferred form for industrial use. Sodium benzoate has an optimum ph range between 2.5 and 4.0. If the ph of the food product is above ph 4.5, acidification may be desirable, the benzoate can be 100 times more active at this optimal ph as compared to ph above 6.0. The microbial level decides the amount of benzoate required. Temperature also plays a part; cold-stored juices need less benzoate. Some fruit juices at 30 C require as much as 0.05% to prevent fermentation. Consequently, juice should be kept cool or have lower numbers of yeast organisms. For preservation of a wide variety of foods, sodium benzoate or benzoic acid is used in amounts of less than 0.1%. Preservation by sulphur dioxide Sulphur dioxide is used to treat fruits and vegetables before and after dehydration to extend the storage life of fresh grapes, and to prevent the growth of undesirable microorganisms during winemaking and the manufacture of juices. Sulphur dioxide is more effective against mould spores and bacteria than against yeast; therefore it is combined with sodium benzoate, which is more effective against yeast, for fruit squashes. Sulphur dioxide is also used as a preservative in manufactured meats, sausage, and soft cheeses. In meat the flesh colour is stabilized. Sulphur dioxide is added to dried fruit in amounts up to 3000 ppm; less in dehydrated vegetables. During their storage, sulphur dioxide slows deteriorative changes, such as severe darkening in colour and development of off-flavours. Its reducing action is valuable in preventing the loss of ascorbic acid in dried fruits and vegetables and the disappearance of beta-carotene (pro-vitamin A) in vegetables. Frequently as much as 90% sulphur dioxide is removed by steam during the cooking of dried fruits and vegetables. Sulphur dioxide is usually applied to vegetables after blanching and before dehydration, in the form of Sodium metabisulphite solution. The use of sulphites or sulphur dioxide, to treat vegetables, prior to dehydration, aids in the prevention of deteriorative changes during dehydration and storage. Sulphur dioxide is a useful agent for the prevention of browning reactions in dried fruits. Treatment with acid Most foods may be preserved by heat treatment when they have a ph lower than 4.0. For this reason several methods have been developed which control the ph through the production of acid, or the addition of some organic acid, like acetic, citric and even lactic acid. The acidification of low-acidity vegetables to less than ph 4.5 for commercial sterilization-based processing, with brief sterilization periods at temperatures of 100 C, is a very practical method to employ on a small-scale and even home processing. Aseptic packaging Here the fruit pulp or juice is passed through computerized equipment with set temperature, duration and flow rate for processing and filling into sterile containers for storage and transport. The principle behind is high temperature short time (HTST) pasteurisation. Microfiltration After suitable dilution the juice extracted is passed through ceramic membrane with micro pores. This technique can also serve to render stability to the product if operated under strictly

20 Harvesting and post-harvest handling of pineapple 20 sterile conditions. The greatest advantage of this process is a high degree of juice clarification and also prevention of discolouration over a course of storage life. PROCESSING It is the transformation of raw ingredients by physical or chemical means into food, or of food into other forms. Food processing combines raw food ingredients to produce marketable food products that can be easily prepared and served by the consumer. Food processing typically involves activities such as mincing and macerating, liquefaction, emulsification, and cooking (such as boiling, broiling, frying, or grilling); pickling, pasteurization, and many other kinds of preservation like canning or other packaging. Objectives of processing Increasing farmer income by the full utilisation of available indigenous raw material and local manufacturing of part or all processing equipment Cutting production costs by better utilisation of local natural resources (solar energy) and reducing transport costs Generating and distributing income by decentralising processing activities and involving different beneficiaries in processing activities (investors, newly employed, farmers and small-scale industry) Maximising national output by reducing capital expenditure and royalty payments, more effectively developing balance-of-payments deficits through minimising imports (equipment, packing material, additives), and maximising export-oriented production Maximising availability of consumer goods by maximisation of high-quality, standard processed produce for internal and export markets, reducing post-harvest losses, giving added value to indigenous crops and increasing the volume and quality of agricultural output PROCESSING OF PINEAPPLE There is a series of physical properties of pineapples that play important roles during processing. It was found that in addition to be considered as a maturity index, translucency is a quality attribute of the fruit. Translucent or semi translucent slices are generally considered as desirable and associated with better flavour. Fully translucent pulp has an overripe flavour, while those not translucent are too sour. As pulp becomes more translucent air cavities decrease in size and therefore porosity. Internal colour affects the appearance and acceptance of the fruit; yellow-gold colour has been regarded as best. It is not merely to satisfy producers and processors by way of higher monitory return but also with better taste and nutrition. According to the Food and Agricultural Organisation's (FAO) definition, processed foods can be of three types: primary, secondary and tertiary. Primary processed foods involve basic cleaning, grading and packaging. Secondary processing means modification of the basic product to a stage just before the final preparation at the consumer's kitchen. Tertiary processing leads to high value-added ready-to-eat products like ice cream, jams, jellies etc. The main objective of processing technique is to convert perishable fruits into stable products with longer life. Main purpose of processing is to minimize the qualitative and quantitative

21 Harvesting and post-harvest handling of pineapple 21 deterioration of the produce after harvest. The popular products prepared using pineapples are juice, squash, halva, jam, candy, pickles, chutney, wine, etc. The Pineapple fruit is processed into a range of refreshing food products. Traditionally pineapple is consumed fresh or canned (Figure 24). Diversification of pineapple products is a good strategy to increase consumption in the main markets of the world. Thus, pineapple is now consumed in the form of single strength or concentrated juice, dehydrated and/or sugared, canned in slices or bits. Among the newer developments are dried chips, cocktail-type drinks, dried powdered, isotonic mixtures and wine; there are also new canned forms as whole fruit, bars, flakes and cubes. Essentially a prime table fruit, pineapple pulp is perfectly suited for conversion to frozen juices, nectars, drinks, jams, fruit cheese, concentrates or to be had by itself or Fig. 24 Canned pineapple with cream as a superb dessert. It can also be used in puddings, bakery fillings, and fruit meals for children, flavours for food industry, and also to make the most delicious ice cream and yoghurt. While the raw fruits are utilized for products like chutney, pickle, sauce. pineapple beverage, etc. ripe ones are used in making pulp, juice, nectar, squash, leather, slices, etc. Major export products include dried and preserved vegetables, jams, fruit jellies, canned fruits and vegetables, dehydrated vegetables, frozen fruits, vegetables and pulps and freeze dried products. Ripe pineapple may be frozen whole or peeled, sliced and packed in sugar (1 part sugar to 10 parts pineapple by weight) and quick-frozen in moisture-proof containers. The diced flesh of ripe pineapple, bathed in sweetened or unsweetened lime juice, to prevent discolouration, can be quick-frozen. Half-ripe or green pineapples are peeled and sliced as filling for pie, used for jelly, or made into sauce. After labelling the cans, they should be packed in strong wooden cases or corrugated cardboard cartons and stored in a cool and dry place. Storage of cans at high temperature should be avoided as it shortens the shelf-life of the product. VALUE ADDITION Value is added to the fruit by changing their form, colour in order to increase the shelf life of perishable fruit. In the current scenario, there is an urgent need to increase the level of value addition and to improve the quality of value added fruit products for domestic and export market. Pineapples are primarily used for food, in the form of value added products like juices, jams, jellies, ice creams and liquors. Any step in the production process that improves the product for the customer and results in a higher net worth, is known as value addition. Typically fruits and vegetables have a low price when they are in the raw state, but can be processed into a range of dried foods, jams, jelly, juice, syrups, pickles, candy, cakes, cookies, ice creams, muffins, etc. (Figure 25) which have a considerably higher value. The high added value means that the amount of food that must be processed to earn a reasonable income is relatively small. Hence, the size and type of equipment required to operate at this scale can be kept to levels that are affordable to most aspiring entrepreneurs. In many countries, vegetables and fruits are among the most accessible raw materials for processing. Pineapples generate

22 Harvesting and post-harvest handling of pineapple 22 substantive income as a fresh fruit and several processed products and by products, which include canned products like juice, slices, jam, beverages and alcoholic drinks. Some value added products made from pineapple are the following. Fruit pulps and juices Pulp or juice of pineapple is extracted by crushing, grinding and straining the fruit content. By using additives it can be stored from six months to more than one year. In off seasons of production, the pulp/juice can be diluted and with supplements can be converted into RTS beverage for consumption. In order to expect least or no changes in the stored fruit pulp, it is advisable to hold the fruit pulp prepared in a hygienic condition, in frozen condition at -30⁰C. The storage life would be minimum of six months. The frozen pulp after thawing can be reconstituted to obtain RTS drinks. Dehydrated products It is a simpler method of processing and extension of storage life by physical removal of water, by hot air drying, which is economical on commercial scale. Here the fresh material is dried to residual moisture of about 5% and depending upon the required retention of pigmentation, flavour and taste. The dried material can be rehydrated using water. The storage life of dried material can be of six months at room temperature. This process offers the scope for reduction in bulk and due to the light weight reduces freight charges. Osmodehydrated and intermediate moisture products of 25% water content merit direct consumption without the need for reconstitution. Pineapple has been known to be excellent for drying. In this product, most of the free water of the fruit is eliminated. To prepare, select fully ripe, fresh pineapple. Remove skin and eyes from Pineapple candy Pineapple jelly Pineapple jam Pineapple syrup Pineapple cake Pineapple ice cream Pineapple muffins Pineapple cookies Fig. 25 Popular value added products of pineapple