Available online at www.sciencedirect.com ScienceDirect Procedia Food Science 3 (2015 ) 413 425 The First International Symposium on Food and Agro-biodiversity (ISFA2014) Development of New Product : Rambutan Pulpy Juice Ermi Sukasih * and Setyadjit Indonesian Centre for Agriculture Postharvest Research and Development Cimanggu Agriculture Campus, Jl. Tentara Pelajar no. 12, Bogor 16114, Indonesia ABSTRACT This study aimed to know the effect of adding pulp in rambutan fruit juice on the characteristics of rambutan juice during storage. Research using the CRD, the treatment were kind of pulp (mandarin and rambutan) and pulp concentration (5%, 7.5%, and 10%). The results showed that the addition of pulp significantly affect the characteristics of rambutan juice (ph, vitamin C, total acid) during storage. Pulpy juice with the most prefered was addition of rambutan pulp as much as 7.5% (w/v) and the addition of citrus pulp as much as 7.5% (w/v) with the score of 3-4 (moderate like - like). 2014 The Authors. Published by Elsevier Ltd. 2015 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license Peer-review under responsibility of the organizing committee of Indonesian Food Technologist (http://creativecommons.org/licenses/by-nc-nd/4.0/). Community Peer-review under responsibility of the organizing committee of Indonesian Food Technologist Community Keywords : pulpy juice, rambutan, citrus, storage INTRODUCTION Native to Southeast Asia s fruit, rambutan (Nephelium lappaceum L.) belongs to the same family (Sapindaceae) as the sub-tropical fruits lychee and longan [1]. This fruit is an important commercial crop in Asia, where it is consumed fresh, canned, or processed, and appreciated for its refreshing flavour and exotic appearance [2]. *Corresponding author. 2211-601X 2015 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of Indonesian Food Technologist Community doi: 10.1016/j.profoo.2015.01.046
414 Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 When the season arrives, the price of rambutan fruit can be decreased dramatically. Therefore, there should be an effort that is able to overcome this price drop by put efforts on realise an added value. Processing of fresh rambutan into new products is one of ways that can be used, one of which is the processing of rambutan fruit into fruit juice. This process can make rambutan stored longer, more practical and make the contents of vitamins and minerals in the fruit more quickly absorbed by the body. The addition of the citrus pulp and rambutan pulp are expected to be the alternative of processed rambutan preferred by consumer. Juice obtained from the fruit pulp is diluted, so it has the similar taste with the original fruit. Commercial production of rambutan juice has certain operation and standards so that the product be accepted widely by society. One of the condition is the contents of vitamins, stabilizers, sugar, total acid, colors, and preservatives in fruit juices. The contents of the fruit juice can be change during storage. Pulpy juice is a relatively new product and not commonly found produced by small scale producer need to be investigated. In Indonesia, the beverage industry with a fruit juice content is one of the processed food by industries categories which growing fast with an average growth rate of 12 percent in the last five years [3]. Product innovation i.e. ready to drink beverage which contain fruit juice in packages, can fulfill the needs of the consumption of fruits in Indonesia which is still relatively low. These innovations can be further developed with the addition of the fruit pulp to increase consumer interest. The addition of citrus and rambutan pulp with different concentrations on rambutan fruit juice can also affect the composition of these fruit juices and their preferences response. Therefore, the study of the effect of the addition of fruit pulp in the rambutan juice during a certain period of storage is necessary to be done. This study aimed to determine the effect of pulp on the characteristics of rambutan fruit juice during storage. MATERIAL AND METHOD Material The equipment used included: scales, blender, juicer, oven, refractometer, ph meter, chromameter, and glassware. The materials used included rambutan cv. Lebak Bulus, distilled water, citric acid 1%, NaOH, carragenan, CMC (Carboxy Methyl Cellulose), sodium benzoate, potassium sorbate, vitamin C, sugar, citrus cv. Medan, NaCl, starch 1%, iodine solution, ph 7 standard buffer, and the indicator phenolphtalein. The study was conducted at the Laboratory Indonesian Center for Agricultural Postharvest Research and Development. Methods
Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 415 Prodution of Pulpy Rambutan Juice Rambutan cv. Lebak Bulus were peeled and put in 1% citric acid solution. Then the rambutan fruit seeds were separated and flesh were soaked in a solution of 1% citric acid for 30 minutes. Rambutan flesh were rinsed with boiled water, then extracted with juicer to get the juice. The juices then were diluted and added food additives. Juices were dilutted at 1: 2 ratio, then heated and the mixing process was the addition of carrageenan 1:25 g/l, CMC 1:25 g/l, 250 ppm sodium benzoate, potassium sorbate 250 ppm, sucrose 15% (w/v), and vitamin C 1000 ppm. After that rambutan juice was pasteurised at 70 C for 15 minutes. Rambutan fruit juice then were put into a 250 ml bottle that has been pasteurised by steaming and already contained the pulp. Preparation of Pulp Pulp added were rambutan and citrus pulp. Rambutan fruit were peeled and separated from the seeds. The rambutan then were washed with boiled water and blended, so that the rambutan pulp ready. Citrus pulp were obtained by separating the epidermis of peeled citrus, chopping with blender. Peeled citrus was soaked in 12% NaOH solution for 30 seconds and then rinsed them with 4% citric acid. Citrus epidermis and seeds were removed, and the fleshed were crushed using blender to obtain pulp. Packaging process was done by firstly put pulp into plastic bottles of 250 ml, followed by pouring pasteurised rambutan juice into the bottle. Treatment and analyses Treatment in this study was the addition of pulp consisting of two types, rambutan and citrus, i.e 5%, 7.5%, and 10%. Each treatment was repeated three times, so the number of samples was 108 bottles. Samples were stored for two weeks at room temperature (27-30 o C) and analysed every week. Analysis were conducted on the ph with a ph meter, total soluble solid (TSS) with a refractometer, color lightness with chromameter, total acid and vitamin C by titration, and organoleptic hedonic. In the organoleptic test panelists were asked to give an assessment by filling out with a questionere score of: (1) very dislike, (2) dislike, (3) slightly like, (4) like, and (5) very like. The data obtained were then to be analysed using Minitab program. RESULTS AND DISCUSSION ph Value The range of ph of pulpy juice rambutan between 4.4-4.7. Analysis of variance anova showed p value 0.01, were significantly different (Figure1). The ph value was in the range of non-acidic
416 Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 ph optimum for the growth of most microbes, which is 4.6 so hopefully microbial growth can be inhibited. Figure 1. The relationship between ph and storage time Pulpy rambutan added with citrus pulp has a higher ph value compared than the addition of rambutan pulp. This is because the rambutan fruit contains organic acid which lower than citrus. The ph value of pulpy rambutan decreased from initial to first week storage. Decreasing of ph during storage is due to the formation of acid by the activity of the product during storage, however, at second week, pulpy rambutan increased. It caused by the use of acids in the fruit as a source of energy and the conversion of sugars to form organic acids [4]. This happens on all treatments and almost all replications, especially with the addition of citrus pulp. Storage time can affect the ph changes, because of the time of observations done in this study is quite short. Therefore the sharp trend for ph value of pulpy rambutan during storage is not available yet. Total Soluble Solid Total soluble solid values can be interpreted as the concentration and amount of soluble solids in fruit juice [5]. The solids can be either glucose, vitamins, minerals, and fiber found naturally in fruits. Total soluble solids is measured in degree brix unit [6]. Degree brix scale of the refractometer is equal to gram weight of 100 g of sucrose of a sucrose solution. If that is observed as the flesh of the fruit, this scale shows the gram weight of sucrose in 100 g fruit flesh. Analysis of variance anova showed p value p 0.05, were not significant. Figure 2 gives the relationship between the value of TSS in pulpy juice rambutan with storage time.
Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 417 Figure 2. The relationship between total soluble solid and storage time Total soluble solid range of pulpy rambutan between 15.9-18.1 o Brix, has increased during storage. Pulpy rambutan with added rambutan pulp has a higher total soluble solid value than the pulp of citrus. It is because the rambutan fruit has a higher starch content than citrus fruit. During the fruit ripening process, starch content decreased, while total soluble solid content would increase, due to increased concentrations of dissolved compounds, especially sugars in the fruit [7]. Respiration and other biochemical reactions in the rambutan fruit will elaborate complex carbohydrates into simple sugars and organic acids. Therefore, the longer the storage time, the higher the value of the total soluble solid generated. Total soluble solids in the treatment of the addition of citrus pulp did not experience a noticeable increase during storage. Some studies indicate that total soluble solid levels reached a maximum at the time of ripe citrus fruit and then decreased after overipe [8,9,10]. The treatment of added pulp rambutan at different concentrations showed no significant differences. Vitamin C In rambutan, vitamin C was the highest content when compared to other vitamins. Pasteurisation processing for juice causing loss of vitamin C up to 50% by oxidation [11]. In this experiment as much as 1000 ppm of vitamin C has been added in this process, other than those naturally occurring in rambutan juice. Figure 3 shows the relationship between vitamin C with storage time. Analysis of variance anova showed p value 0.01, which is significantly different.
418 Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 Figure 3. The relationship between vitamin C and storage time The range of vitamin C in pulpy rambutan were 70-90 mg/100 g. Pulpy juice rambutan with added rambutan pulp treatment has higher vitamin C value than added of citrus pulp treatment. This is due to vitamin C of the rambutan fruit initially is higher at around 56.68 mg/100 g compared with citrus fruit which is only about 46.92 mg/100 g of the fruit flesh [12]. The level of vitamin C in pulpy juice rambutan will be decreased from initial to first week storage. However, at second week, it will increased again. This was happens on all treatments and almost all replications. The trend results of the analysis of the vitamin C is almost the same that happened to the results of the analysis of the ph value pulpy juice rambutan. Total acid Total acid by titration indicates the levels of acid contained in the rambutan fruit and juice. The main organic acids content in the rambutan fruit is not only citric acid and malic acid but also ascorbic acid [13]. Total acid in fruit juices are usually influenced by citric acid component found naturally in fruits. In the commercial juice production, the addition of acid aims to give a sour taste and also can as a preservative and antimicrobial substance. Acid levels and ph will be related to one another. The addition of an acid into a beverage product will increase the concentration of H + ions [14]. With the presence of these ions, the ph value will decrease and will increase the value of total acid. The ph value is inversely proportional to the value of total acid. Analysis of variance anova showed p value 0.01, which is significant.
Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 419 Figure 4. The relationship between acid total and storage time Figure 4 shows the relationship between total acid with storage time. The total value of the acid on rambutan pulpy juice ranged from 0:15 to 0:19%. Pulpy juice rambutan with added mandarin pulp treatment has higher total acid value than added of rambutan pulp treatment. It is because the citrus fruit contains a higher total acid is about 0.7-1.35 g/100 g than rambutan fruit acids, only 0:31 g/100 g [12]. Total acid content of the pulpy juice rambutan decreased from initial to first week storage. However, in the 2nd week of storage, the total acid rambutan pulpy juice increased. This trend result occurs similarly with the results of the other analysis such as the analysis of ph and vitamin C. Lightness (Color) Rambutan fruit has white to milky white color. Addition the pulp with different concentrations and storage time can affect the lightness of the color of the fruit juice. Addition citrus pulp orange juice change into a slightly yellowish color. It can be seen from the color brightness values obtained. The higher of the concentration pulp added, the higher lightness value of pulpy juice rambutan. Figure 5 shows the relationship between lightness value and the storage time.
420 Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 Figure 5. The relationship between lightness and storage time Pulpy juice rambutan with addition of 7.5% rambutan pulp, 5% and 10% mandarin, showed that the longer of the storage, the lower the level of pulpy jus rambutan in lightness, while the other treatment was increased (Figure 5). Analysis of variance anova showed p value p 0.05, is not significant. Changes in the lightness of this color may occur due to differences in the composition of the sample. Acidity, ph value has an influence on changes in lightness of fruit, low ph (acid condition) in fruit juice will reduce the lightness of the color of rambutan juice. The higher acidity can cause browning reactions during storage [15]. Almost all of samples, their lightness colors decreased from initial to first week of storage, except of addition 5% mandarin pulp. However, at second week of storage, lightness of pulpy juice rambutan increased again only in few samples. Hedonic Test Color Color is one of the most important parameters in the organoleptic test because for the first time consumers will see the color of the food before eating it. The results of the color analysis with Minitab program can be seen in Figure 6.
Ermi Sukasih and Setyadjit / Procedia Food Science 3 (2015) 413 425 Figure 6. Color hedonic of various treatment during storage Figure 6 shows the relationship between the color of the sample with panelists respons, the effect of storage on color preferences rambutan pulpy juice, and also the interaction between the sample. The results of the analysis using the Minitab program showed that sample color most preferred by consumers is addition of 5% rambutan pulp and 10% citrus pulp with an average value of 3.7 (slightly like to like) of the maximum value of 5 (very like). Figure 8 also shows that the longer the storage time, consumers increasingly prefer the color of the rambutan pulpy juice. Its because the longer the storage, increasing the lightness of rambutan juice thus increasing of the preference. Flavor In addition to color, quality properties rambutan pulpy juice tested was flavor. The results of the analysis of aroma pulpy juice rambutan with Minitab presented in Figure 7. Panelists provide an assessment of the numbers 1 to 5 (1 to strongly dislike and 5 for very like). The most preferred color 421
422 Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 respons panelists was pulpy juice rambutan with addition rambutan pulp 5% and 10% citrus with an average value of 3.769 (slightly like to like) of the maximum value of 5 (very like). Figure 7. Flavor hedonic of various treatment during storage In the figure, it also can be seen the interaction between the sample, the storage time and the aroma liking of pulpy juice rambutan by panelists. Judging from the results of the analysis using the Minitab program, samples of the most prefered by consumers is rambutan 7.5% to the value of 3.5 (slightly like to like) and to pulp of citrus 7.5% with an average value of 3.2 (slightly like to like) from the value a maximum of 5 (very like). Figure 7 also shows that the longer the storage time, consumers increasingly prefer the aroma of the rambutan pulpy juice, which reached 3.7 (slightly like to like) of the maximum value of 5 (very like). Similarly, [16] reported that during the processing and canning of fruit products there were loss of aroma. These have been accelerated by acidic medium.
Ermi Sukasih and Setyadjit / Procedia Food Science 3 ( 2015 ) 413 425 423 Taste In addition to color and aroma, other quality properties tested is taste. The results of the analysis of flavor of pulpy juice rambutan with Minitab is presented in Figure 8. This figure shows the graph of storage time interaction and taste of pulpy juice rambutan according to panelists. Figure 8. Taste hedonic of various treatment during storage Based on the graph it can be seen the relationship between the samples with a sense of pulpy juice rambutan by the panelists, the effect of storage on flavor preferences. Pulpy juice rambutan, and the interaction between the samples, and storage time and the most favorite samples in flavor by panelists. Judging from the results of the analysis using the Minitab program, taste samples of the most preferred by consumers is rambutan 7.5% to the value of 3.7(slightly like to like) from the value a maximum of 5 (very like). Figure 8 above also shows that the most consumers prefer the taste of pulpy juice rambutan on the 2nd week of storage, which reached 3.6 (slightly like to like) of the maximum value of 5 (very like). However, at first week storage, consumers was less like the taste of the rambutan pulpy juice when compared with initial storage. Panelists prefered the taste of pulpy juice rambutan at second week storage which can be caused levels of sugar content (TSS values) and acidity (ph) of the sample which is higher. A preference of taste is caused by the better balance of sucrose and acidity to form prominent flavor [17].
424 Ermi Sukasih and Setyadjit / Procedia Food Science 3 (2015) 413 425 General Preferences Properties of the quality of rambutan pulpy juice tested was general preferences by the panelists. The results of the analysis of the general preference with Minitab program presented in Figure 9. Two-Way For by nweek Two -W aanom y AN O M General f or Ke s Preference uk a a n b g gu k e -, Sample S of-, a mpe l y Mi A l ph a = 0. 05 Interaction Int e r a ct io n Ef feffects e ct s 0.5 0.0-0 0.5.5 Sam mpel p el Weeks Min gg uof-k e- % % % % % % % % % % % % % % % % % % 10 5.5 10 5.5 10 5.5 10 5.5 10 k 5 7.5 10 n 5 7.5 k ruk k 7 an ta n n 7 uk ruk k 7 an ta n n 7 uk ru k an ta n u r je eru bu t bu ut a jer je eru but bu uta jer je eru but bu uta je j m am b j m am b j m am mb m m r r a a r r ra r ra ra ra 00 11 Ef f e ct s for M a in Effects Main fo r Weeks M in g g u of- ke - Mean n a e M 3. 68 5 7 3. 6 3. 48 8 9 3. 4 3. 2 3. 29 2 1 0 1 Mi ng g u ofkeweeks 2 0. 56 3 0-0. 56 3-0 22 n a e M Mean Effect tc e ff E M a in EEffects f f e ct s f osample r Sa m p e l Main 3. 8 3 6 5 3. 4 8 8 9 3. 1 4 1 3 % % % 10 % n 5% 7.5 % 10 k 5 7. 5 n k a n ru ru k ta bu t ru ta je je bu je m mbu m a r a ra r SampleSa S a mpel mpe l 3.75 3.50 3.25 3..00 3 00 Figure 9. General preferences hedonic of various treatment during storage Based on the above graph it can be seen the relationship between the sample in general preference of pulpy juice rambutan by the panelists, the effect of storage and the interaction between samples, storage time. Judging from the results on the analysis using the Minitab program, in general preference, the sample which has the most preference by consumers is rambutan pulp 7.5% to the value of 3.7 (slightly like to like) and to pulp citrus which is 7.5% with an average value of 3.4 (slightly like to like) of the maximum value of 5. Figure 9 above also shows that most consumers preference to pulpy juice rambutan on the second week of storage, which reached 3.6 (slightly like to like) of the maximum value of 5 (very like). However, at first week storage panelist are less like the taste of rambutan pulpy juice compared with initial storage. CONCLUSION Pulpy juice rambutan with addition of both rambutan and citrus pulp were pulp were the most prefered juice by panelist. The longer the storage time, the pulpy juice with rambutan pulp addition hashigher preference by panelist. Produced pulpy juice s characteristics were similar to the pulpy
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