EFFECT OF CARBONATION ON THE CHEMICAL COMPOSITION AND SHELF LIFE OF CARROT JUICE Abstract:
Carrot (Daucas carota) is considered as important agricultural crop for human consumption. Carrot juice has very short shelf life and in this study the carbonation was carried out to study its effect on the shelf life, physic- chemical properties and the organoleptic properties. The carrot juice was prepared and its carbonation was done after carbonation different treatments were stored in colored and transparent bottles. These treatments were observed at regular intervals of time i.e. 0, 15, 30 and 45 days. The carbonation brought decrease in pH and ascorbic acid contents and increase in TSS and reducing sugars. The mineral stability of carbonated carrot juice maintained and the carbonated carrot juice remained acceptable for its color, flavor, taste and overall acceptability during storage. There was no significant difference in the carbonated carrot juice stored in transparent and colored bottles except the ascorbic acid contents which were high in colored bottles at 45th day than transparent bottles due to less penetration of light in colored bottles. Key Words: Daucus Carota.
Carrot is a plant of ancient cultivation especially in the countries bordering the Mediterranean. The wild ancestors of carrot are from Afghanistan, which remain the center of diversity of Daucus Carota (Alimula, 1989). Carrots are cultivated on an area of 13.9 thousand hectares, with 242.3 thousand tons production (FAO, 2007, 2008). It is most prevalent vegetable grown in Pakistan. In Pakistan carrot production during 2005-06 was 187 thousand metric tons (Anonymous, 2006).carrot occupies a prominent position owing to its dietetic and economic values. Carrot root is used as vegetable constituent in soups, stews and curries. The grated carrot used as salad while tender root as pickle (Alimulla, 1988). Fresh fruits and vegetables have been used by man from ancient time. These not only provide energy to the body but also are good sources of vitamins and minerals (Van-Aradal, 1963). Fresh carrot juice contains water 86.4%, carbohydrate 8.0 %, protein 0.8 % and dietary fiber 0.2 % (Salunkle et al., 1973). Moreover the carrot juice is also well known due to its medicinal values as it is effective against urogenital diseases (Salunkle. 1973). Bao and Chang (1994) reported that carrot pulp contained 4-5% protein, 8-9% reducing sugars and 5-6% minerals. Carrot juice has very short shelf life. Normally the juice of carrot is only available in winter. Due to this it is not possible to market it commercially at large scale. Shelf life of juice can be enhanced by various methods like canning, heat treatments, chemical preservatives and carbonation. But among these, carbonation is most effective as it does not destroy the nutrient contents of the product (Elahi, 1979). Carbonation of juice not only improves shelf life but also enhances the organoleptic properties of the product (Alimulla, 1988). Ueda (1987) conducted the studies on carbonation of carrot juice and noticed that shelf life of juice was increased up to 250 % without using any preservative. Vyrodova et al. (1988) conducted study on chemical composition of carrot juice and reported that beta-carotene contents were 5.90 mg/100 mL. Chen et al. (1995) detected the changes of carotene, color and vitamin C contents during processing of carrot juice. The effects of various processing methods on the carrot juice carotene, color and vitamin C contents were studied. The canning resulted in highest destruction of carotene. Carrot juice color changed from red to yellow during processing. The vitamin C contents decreased along with increasing temperature and storage time. The main objective of this study was to evaluate the stability of carrot juice during storage that was subjected to carbonation and to determine the effects of carbonation on the physico- chemical properties of carrot juice but...
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