PRESERVATIVES TO ENHANCE SHELF LIFE AND QUALITY OF KINNOW JUICE STORED UNDER REFRIGERATED CONDITION

Transcription

1 Original Research Article Allied science International Journal of Pharma and Bio Sciences ISSN PRESERVATIVES TO ENHANCE SHELF LIFE AND QUALITY OF KINNOW JUICE STORED UNDER REFRIGERATED CONDITION ANIL DHAKA 1, MADHU SHARMA 2 AND SHAILESH KUMAR SINGH 1* 1 Department of Horticulture, Lovely Professional University, Phagwara, Punjab , India 2 Department of Vegetable Science, Punjab Agriculture University, Punjab , India ABSTRACT Kinnow (Citrus nobilis Citrus deliciosa L.) is a widely grown Citrus species known for its high quality fruit juice with good storage life. The present investigation is concerned with the enhancement of shelf-life of Kinnow fruit juice through refrigeration storage and addition of preservatives. Fruit juice was prepared from fruits harvested at complete physiological maturity and potassium meta-bisulphite or sodium benzoate alone or in combination were added as preservatives to enhance shelf life of fruit juice. Further, bottled fruit juices were stored under refrigerator and quality was evaluated at 15 days interval for 45 days. The experimental findings showed that TSS, ascorbic acid, reducing sugar and total sugar were increased up to 45 days of storage and maximum value was reported in T 6 (13.27 o Brix, 29.33mg/100ml, 3.61% and 8.01%, respectively) followed by T 8 (12.87 o Brix, 28.67mg/100ml, 3.57% and 7.97%, respectively) at 45 days of storage while titrable acidity ranged from 1.17 to 1.18 % for different treatments in comparison to untreated juice (1.21%). The minimum absorbance at 440 nm wavelength was reported in T 6 ( ) while microbial count was minimum in T 7 (2.58 x x 10 5 ). The investigation clearly revealed that the shelf-life of Kinnow juice can be extended up to 45 days without qualitative loss when 0.05 % of potassium meta-bisulphite or 0.05% of sodium benzoate were added alone or in combination. KEYWORDS: Absorbance, Ascorbic acid, Kinnow, Preservatives, Refrigerator, Shelf-life SHAILESH KUMAR SINGH Department of Horticulture, Lovely Professional University, Phagwara, Punjab , India *Corresponding Author B - 629

2 INTRODUCTION Citrus fruits are intensively cultivated fruit throughout the tropics and subtropics, belong to sub family: Aurantioideae, family: Rutaceae and order: Geraniales. Genus Citrus consists of about 162 species among which the commercially grown species include: Citrus reticulata Blanco, C. sinensis (L.) Osbeck, C. paradise Macf, C. grandis Osbeck, C. aurantifolia Christm and C. limon (L.) Burn F 1. Kinnow (Citrus nobilis Citrus deliciosa L.) is an interspecific hybrid with superb fruit quality, higher yield potential, better adoptability, beautiful appearance and excellent nutritional value in terms of vit-c, A & B and minerals like calcium, phosphorus and iron 2.There is a glut of Kinnow fruits in market during harvesting season, so the farmers are forced to sell their produce at cheap prices and suffer significant economic loss. These fluctuations in prices can be controlled by selling the fruit in phases or by storing them in the juice form. As reported by 3 natural juice is short lived even at low temperature storage. Preservation of fruit juice is an industrial practice in the countries which are enriched with eco-physiological conditions suitable for fruit production and have well established infrastructures for storage and preservation to improve shelf life of fruits and fruit juice and to ensure year around availability 4.The introduction of pasteurization technique and refrigerated storage has given a great stimulus to food preservation industry. Use of chemical preservatives, however, plays a very important role in ensuring safety and quality of stored foods. Preservatives are chemical agents intentionally added to food products to prevent or inhibit spoilage caused by moulds, yeasts and bacteria. Although a number of preservatives are being used to preserve food, sources of sulfur dioxide like KMS (Potassium metabisulfite) and salts of benzoic acid are still key preservatives and are widely used. The present research work put focus on the impact of preservatives on fruit juice chemistry, browning and microbial count of Kinnow juice stored under refrigerator condition. MATERIALS AND METHODS The investigation was carried out in Postharvest Technology Laboratory, Department of Horticulture, Lovely Professional University, Phagwara, Punjab, India. Extraction of juice Fruit juice was prepared from fruits harvested at complete physiological maturity from Kinnow orchard of University and preservatives were added. The procedure is given below: a. Selection of uniform and disease free Kinnow fruits. b. Packing of fruits in plastic crates and transportation to laboratory. c. Sorting and washing of fruits. d. Removal of fruit rind. e. Use of automatic citrus juice extractor for extraction of juice. f. Filtration of juice to obtain a clear juice. g. Adding preservatives as per treatment. h. Pouring of fruit juice in sterilized crown glass bottles (200 ml). i. Pasteurization of air tight corked Kinnow juice containing bottle in boiling water for 30min (at 63 0 C temperature of juice) as per treatment. Preparation of Juice The preservatives were added as per treatments given: Fruit juice without preservatives, pasteurization or heating-t 1 ; Fruit juice pasteurized at 63 0 C in boiling water for 30 minutes-t 2 ; Fruit juice heated to 85 0 C-T 3 ; 0.05% of Sodium benzoate as preservative-t 4 ; 0.1% of Sodium benzoate as preservative-t 5 ; 0.05% of KMS (Potassium metabisulfite) as preservative-t 6 ; 0.1% of KMS as preservative-t 7 ; and combination of 0.05% of each of Sodium benzoate and KMS as preservatives-t 8. The treated juice were stored under refrigerator condition (4 0 C) and observations were recorded at 0, 15, 30 and 45 days of storage. Determination of Total soluble solids ( 0 Brix) Fruit juice taken out from refrigerator and kept out to bring it at normal temperature. A drop of fruit juice was taken and TSS was measured by using hand refractometer and was expressed in 0 Brix 5. Determination of Ascorbic acid (mg/100ml of juice) Ascorbic acid content of the juice was calculated by using metaphosphoric acid (3%) and 2,6- dichlorophenolindophenols solution through titration method 5. The ascorbic acid (vitamin-c) content of juice was determined by diluting the known volume of juice with 3 per cent metaphosphoric acid and titrating it against 2,6-dichlorophenolindophenols dye solution until a faint pink colour was obtained. The results were expressed as mg of vitamin C in 100 ml juice. Standardization of the dye 2,6- Dichlorophenolindophenol was done by titrating it against standard ascorbic acid solution. The standard was prepared by dissolving 100mg of pure L-ascorbic acid in 100 ml of 3 per cent metaphospheric acid, an aliquot (1 ml) was used for titration. The ascorbic acid was calculated by following formula: B - 630

3 Determination of Titratable acidity (%) Total acid was determined by diluting the known volume of juice and titrating the same against standard N/10 sodium hydroxide solution, using phenolphthalein indicator 6. Active acidity (ph) Electronic ph meter was used to determine ph of fruit juice. Sugars Total and reducing sugars in Kinnow fruit juice were estimated by Lane and Eynon s method reported by 7. The reagents used were Fehling A and B solution, Methylene blue indicator, Neutral lead acetate and Potassium oxalate. In a conical flask, 5 ml each of Fehling s solution A and B were taken. Took the sugar extract in burette and titrated against boiling Fehling s solution by using methylene blue as an indicator. The end point was indicated by the appearance of brick red precipitates. A measured amount (50 ml) of the sugar extract was taken in a 100 ml volumetric flask to which 1.0 ml concentrated HCl was added and kept for hydrolyzation over night at room temperature. Next day, the solution was neutralized with saturated NaOH solution followed by a drop of phenolphthalein; finally the volume was made up to the mark with distilled water. This solution was then titrated against Fehling s A and B as was done previously in case of reducing sugars. Titre value was used to calculate the per cent total sugar using the formulae. Determination of Browning Samples of fruit juice were taken for centrifugation at 4000 rpm (revolution per minute) for 15 minutes. Fifteen ml of alcohol was mixed with 10 ml of fruit juice after centrifugation and kept for 30 min. The mixture was filtered and absorbance was measured at 440nm in reference to 60% aqueous alcohol as blank by using spectronic-20 device. Determination of Microbial counts Microbial counts was determined by a series of dilution and spread plate method and were expressed in terms of number of colonies. Statistical analysis The data were analyzed through completely randomized design (C.R.D.). The overall significance of differences among the treatments was tested by using critical difference (C.D.) at 5% level of significance. RESULTS AND DISCUSSION Total Soluble Solid (TSS) The observation recorded on TSS of Kinnow juice during refrigerator storage confirms that TSS content was significantly affected by addition of preservatives (Fig.1). Increase in TSS was observed to be maximum in T 6 [0.05% KMS ( º brix)] followed by T 8 [0.05% KMS+ 0.05% SB ( º brix)] and T 7 [0.1% KMS ( º brix)] in comparison to T 1 [control ( º brix)]. Increase in TSS during storage might be associated with acid hydrolysis of complex-insoluble polysaccharides into simple soluble monosaccharides in prevailing acidic medium created by SO 2 released from KMS as confirmed by 8 in orange juice. The positive correlation between TSS content and storage duration was reported by 9 in blended Kinnow juice under refrigerated storage condition. B - 631

4 Figure 1 Total Soluble Solids of refrigerated fruit juice of Kinnow Ascorbic acid The data pertaining to the impact of preservatives and heating on ascorbic acid content of Kinnow juice were found to be significant at all days of observation (Fig. 2). In the refrigerator storage, the significantly minimum (6.82, and %) loss of ascorbic acid was reported with T 6 (0.05% KMS) followed by T 8 (0.05% KMS % SB 6.93, and 25.88%) and T 7 (0.1% KMS 6.98, and %) while the maximum (21.22, and %) loss was reported with T 3 (heat processed Kinnow juice) respectively at 15, 30 and 45 days of storage, respectively (Fig. 3). KMS is potential source of SO 2 which is released after reaction with moisture of juice and being antimicrobial agent might be responsible to prevent degradation of ascorbic acid of Kinnow fruit juice during storage Pasteurization induced initial break down of ascorbic acid might be reason behind lower value of ascorbic acid in T 2 and T 3 and is in conformity with findings of 14 in aonla juice and that of 15 for citrus juice. Breakdown of ascorbic acid during storage might be light or metallic ion induced as reported by Figure 2 Ascorbic acid of refrigerated fruit juice of Kinnow Figure 3 Percentage loss of Ascorbic acid in refrigerated fruit juice of Kinnow B - 632

5 Titratable acidity The observation on change in titratable acidity of Kinnow juice by using different preservatives under refrigerator storage condition was reported to be significant for the all days of storage (Fig. 4). It has been observed that the least acidity loss and highest acidity (0.96%) was in T 6 (0.05% KMS) and T 8 (0.05% of each KMS and SB) whereas least acidity (0.81%) was in T 1 at 45 days of refrigerator storage. Alteration in metabolism and enzymatic activity might be reason behind loss of acidity as confirmed by findings of 21. The decrease in acidity observed during storage might be light induced break down of organic acid of juice and their interaction with enzymes Figure 4 Titratable acidity of refrigerated fruit juice of Kinnow ph The data pertaining to the effect of preservatives and the heat treatment given to the Kinnow juice showed significant effect on ph (Fig. 5). The least increase in ph was observed in T 6 [0.05%KMS ( )] followed by T 8 [0.05%KMS % SB ( )] at 45 day of refrigerator storage. Highest rise in ph was observed in T 1 ( ), T 2 ( ) and T 3 ( ) at 45 days of refrigerator storage. The significant elevation in ph during refrigerated storage of fruit juice could be associated to decreasing acidity Figure 5 ph of refrigerated fruit juice of Kinnow Reducing Sugar All the preservatives like KMS, Sodium benzoate and their combination had significantly affected the level reducing sugar in Kinnow juice (Fig. 6). The maximum elevation in reducing sugar was identified in T 6 [0.05% KMS ( %)] followed by T 8 [0.05% KMS +0.05% SB ( %)] and T 7 [0.1% KMS ( %)] as compare to T 1 [control ( %)] in low temperature storage. The elevation in level of reducing sugar during refrigerated storage due to addition of KMS as preservative might be accounted for conversion of nonreducing sugar into reducing sugar in the prevalent acidic medium created due to release of SO 2 from KMS. The similar findings were reported by 21, Increase in reducing sugar of fruit juice added with sodium benzoate as preservatives had also been reported by 8,28. Total sugar The observations related to the effect of addition of preservatives on total sugar content revealed that the total sugar significantly increased with the addition of KMS in different concentration (Fig. 7). It was highest in T 6 [0.05% KMS ( %)] which was at par with T 8 [0.05 % KMS+0.05 % SB ( %)] and T 7 [0.1 % KMS ( %)] while lowest in T 1 [control ( %)]. The increase in total sugar with the passage of the days of storage has been reported by Acid induced hydrolysis of poly-saccharides in KMS preserved juice might be reason behind increased sugar content of Kinnow juice 21,26. B - 633

6 Figure 6 Reducing sugar of refrigerated fruit juice of Kinnow Figure 7 Total sugar of refrigerated fruit juice of Kinnow Browning Non enzymatic browning was observed to be lowest in T 6 ( ) followed by T 8 ( ) and T 7 ( ). The untreated fruit juice (T 1 ), pasteurized fruit juice (T 2 ) and heat treated fruit juice (T 3 ) showed greater extend of browning after 30 days of storage (Fig. 8). SO 2 liberated during hydrolysis of KMS might be responsible for inhibiting non-enzymatic browning of fruit juice as reported by 9, Figure 8 Browning of refrigerated fruit juice of Kinnow Microbial counts The data revealed that the chemical preservatives had significantly inhibited the microbial loads in comparison to untreated juice, pasteurized juice and heat treated juice (Table 1). The minimum (2.58 x 10 3, 1.70 x 10 4 and 1.30 x 10 5 ) microbial count was recorded in T 7 followed by T 8 (2.80 x 10 3, 2.83 x 10 4 and 1.52 x 10 5 ), T 6 (3.10 x 10 3, 2.93 x 10 4 and 1.74 x 10 5 ), T 5 (3.40 x 10 3, 3.63 x 10 4 and 2.01 x 10 5 ) and T 4 (3.93 x 10 3, 3.83 x 10 4 and 2.40 x 10 5 ) at 15, 30 and 45 days of storage of fruit juice in refrigerator, respectively under. The microbial count of stored fruit juice was increased slowly which might be due to antimicrobial compounds present in fruit juice 33. Inhibitory response of KMS on multiplication of microbes in fruit juice during storage has been reported by while inhibitory effect of SB was reported by B - 634

7 Table 1 Microbial population of refrigerated fruit juice of Kinnow Treatments Microbial counts Days 0 day 15 days 30 days 45 days T x x x x 10 5 T x x x x 10 5 T x x x x 10 5 T x x x x 10 5 T x x x x 10 5 T x x x x 10 5 T x x x x 10 5 T x x x x 10 5 CONCLUSION KMS (Potassium metabisulfite) and SB (Sodium Benzoate) can be added as preservatives in Kinnow fruit juice to enhance shelf life and retain consumer acceptability under refrigerated storage. The analysis reflects that chemical and microbial quality was retained for 45 days without loss of the nutritive value and acceptability of juice. The TSS and sugar content was higher while there was minimum loss of ascorbic acid when juice was stored under refrigerated condition with 0.05% potassium metabisulphite as preservatives. CONFLICT OF INTEREST Conflict of interest declared none. REFERENCES 1. Ezeabara CA, Okeke CU, Aziagba BO. Flavonoid content of Citrus species grown in Awka, Anambra State, Southeastern Nigeria. International Journal of Agriculture and Biosciences. 2013; 2(3): Nawaz MA, Ahmad W, Ahmad SAEED, Khan MM. Role of growth regulators on preharvest fruit drop, yield and quality in Kinnow mandarin. Pak. J. Bot. 2008; 40(5): Charalambous G. Shelf life studies of foods and beverages. Elsevier. Science; p Franke AA, Cooney RV, Henning SM, Custer LJ. Bioavailability and antioxidant effects of orange juice components in humans. J. Agric. Food Chem. 2005; 53(13): Chemists AOA, Cunniff P. Official methods of analysis Association of Official Analytical Chemists, Washington, D. C.; International Official methods of analysis ofaoac International: AOAC International; Ranganna S. Handbook of analysis and quality control for fruit and vegetable products. Tata McGraw-Hill Education Publishing Co. Ltd. New Delhi; Shahnawaz M, Sheikh SA, Minhas S. Role of sodium benzoate as a chemical preservative in extending the shelf life of orange juice. Global Adv. Res. J. Food Sci. Technol. 2013; 2(1): Bhardwaj RL. Physico-chemical, sensory and microbiological quality of Kinnow juice stored in refrigerated storage condition. Asian J. Dairy. Foods Res. 2013; 32(3): El-Ashwah ET, Tawfik MA, El-Hashimy FS, Raouf MS, Sarhan MAI. Chemical and physical studies on preserved Benzahir lime juice. Sudan J. Food Sci. Technol. 1981; 13: Heldman, D. R. (Ed.). Food process engineering. Springer Science & Business Media; Negi PS, Roy SK. Effect of blanching and drying methods on β-carotene, ascorbic acid and chlorophyll retention of leafy vegetables. LWT- Food Science and Technology. 2000; 33(4): Mathooko FM, KiniiyaEN. Ascorbic acid retention in canned lime juice preserved with sulfur dioxide and benzoic acid. African J. Food Nutritional Sci. 2002; 2(1): Jain SK,Khurdiya DS. Ascorbic acid content and non-enzymatic browning in stored Indian gooseberry juice as affected by sulphitation and storage. J. Food Sci. Technol. 2009; 46(5): Blasco R, Esteve MJ, Frı gola A, Rodrigo M. Ascorbic acid degradation kinetics in mushrooms in a high-temperature short-time process controlled by a thermoresistometer. LWT-Food Sci. Technol. 2004; 37(2): Bhargawa S,Kapoor S, Ranote PS, Sharma S. Studies on Aloe Juice Supplemented Kinnow Nectar. Res. J. Agriculture and Forestry Sci. 2014; 2: Ahmed M, Ahmad A, Chatha ZA, Dilshad SMR. Studies on preparation of ready to serve mandarin (Citrus reticulata) diet drink. Pak. J. Agri. Sci. 2008; 45(4): De Carvalho JOELIA, Maia GA, De Figueiredo RW, De Brito ES, Rodrigues S.Storage stability of a stimulant coconut water-cashew apple juice beverage. J. Food Process. Preserv. 2007; 31(2): Kabasakalis V, Siopidou D, Moshatou E. Ascorbic acid content of commercial fruit juices and its rate of loss upon storage. Food Chemistry. 2000; 70(3): Burdurlu HS, Koca N,Karadeniz F. Degradation of vitamin C in citrus juice concentrates during storage. J. Food Eng. 2006; 74(2): B - 635

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