Abstract
Date palm (Phoenix dactylifera) is widely cultivated in Kutch district of Gujarat and the fruits are harvested at immature stage before the onset of monsoon to prevent spoilage. The immature date fruits with less commercial value were used for processing into date juice concentrate. Immature dates were crushed and treated with 0.1% pectinase enzyme for 120 min to obtain maximum juice. Date juice was found to be rich in reducing sugars (16.1%) and total sugars (18.3%). Juice was pasteurized at 85°C to inactivate the enzyme, cooled and centrifuged at 3000 rpm to get clear juice. The juice was concentrated in a thin film evaporator to a total soluble solids (TSS) of 76°Brix in 2 passes. Chemical composition of date juice during different stages of concentration was determined. Date juice concentrate was packed in low density polyethylene bags of size (22 cm × 14 cm) and frozen in blast freezer at −40°C and stored at −20°C. Storage of date juice concentrate at −20°C for 6 months indicated no significant changes in TSS, acidity, ascorbic acid, total sugars and pH. Hunter colour lightness L, and redness a values of date juice concentrate decreased whereas b values increased during storage. Date juice concentrate was stable during 6 months storage could be reconstituted for preparing ready-to-serve beverages with acceptable sensory quality.
Keywords: Dates, Date juice, Juice concentrate, Enzyme clarification, Date beverage
Full Text
The Full Text of this article is available as a PDF (695.1 KB).
References
- Al-Hooti S., Sidhu J.S., Al-Otaib J., Al-Ameeri H., Qabazard H. Date bars fortified with almonds, Sesame seeds, oat flakes and skim milk. Pl Food Human Nutr. 1997;51:125–135. doi: 10.1023/A:1007959526896. [DOI] [PubMed] [Google Scholar]
- Al-Hooti S., Sidhu J.S., Al-Otaib J., Al-Ameeri H., Qabazard H. Utilization of date fruits at different maturity stages for variety pickles. Advn Food Sci. 1997;19:1–7. [Google Scholar]
- Al-Hooti S., Sidhu J.S., Al-Otaib J., Al-Ameeri H., Qabazard H. Processing of some important date cultivars grown in United Arab Emirates into chutny and relish. J Food Proc Presrv. 1997;21:55–58. doi: 10.1111/j.1745-4549.1997.tb00767.x. [DOI] [Google Scholar]
- Amerine M.A., Pangborn R.M., Roesser E.B. Principals of sensory evaluation of food. London: Academic Press; 1965. p. 5. [Google Scholar]
- Official methods of analysis. 17th edn. Maryland, USA: Association of Official Analytical Chemists; 2000. [Google Scholar]
- Bolin H.R., Salunkhe D.K. Physico-chemical and volatile flavour changes occurring in fruit juices during concentration and foam mat drying. J Food Sci. 1971;36:665–668. doi: 10.1111/j.1365-2621.1971.tb15156.x. [DOI] [Google Scholar]
- Demeczky M., Khell-Micklein M., Godek-Kerch E. Developments in food preservation — 1. London: Stuart Thorne Applied Science Publ; 1981. The preparation of fruit juice semi concentrates by reverse osmosis; pp. 93–119. [Google Scholar]
- Floribeth V., Celsa L., Cooke R.D. A study of the production and clarified banana juice using pectinolytic enzymes. J Food Technol. 1981;16:115–125. [Google Scholar]
- Hunter S. The measurement of appearance. New York: John Wiley and Sons; 1975. pp. 304–305. [Google Scholar]
- Khamrus K., Pal D. Application of reverse osmosis for concentration of Kinnow mandarin juice. J Food Sci Technol. 2002;39:310–312. [Google Scholar]
- Kulkarni S.G., Vijayanand P., Aksha M., reena P., Ramana K.V.R. Effect of dehydration on the quality and storage of immature dates (Pheonix dactylifera) LWT Food Sci Technol. 2008;41:278–283. doi: 10.1016/j.lwt.2007.02.023. [DOI] [Google Scholar]
- Medeni M. Production of pomegranate juice concentrate by vacuum heating methods: colour degradation and kinetics. J Food Eng. 2006;72:218–224. doi: 10.1016/j.jfoodeng.2004.11.012. [DOI] [Google Scholar]
- Ranganna S. Hand book of analysis and quality control for fruit and vegetable products. 2nd edn. New Delhi: McGraw Hill Publ Co. Ltd.; 1986. pp. 12–16. [Google Scholar]
- Sandhu K.S., Bhatia B.S., Shukla F.C. Physico-chemical changes during storage of Kinow mandarine oranges and pineapple juice concentrate. J Food Sci Technol. 1985;22:342–345. [Google Scholar]
- Steel R.G.D., Torrie J.H. Principles and procedures of statistics. New York: Mc Graw — Hill; 1980. [Google Scholar]
- Thakur N.K., Lal Kaushal B.B., Joshi V.K. Effect of different conditions of storage on physico-chemical and microbiological qualities of debittered kinnow juice concentrate. J Food Sci Technol. 2000;37:415–418. [Google Scholar]
- Vayalil P.K. Antioxidant and antimutagenic properties of aqueous extract of date fruit (Phoenix dactylifera L. Arecaceae) J Agric Food Chem. 2002;50:610–617. doi: 10.1021/jf010716t. [DOI] [PubMed] [Google Scholar]