Effect of freeze-drying and storage on β-carotene and ascorbic acid stability of mango milk shake

Freeze-drying is a process which retains the nutritional, sensorial and functional qualities of foods, together with extreme reduction in weight, high solubility, long shelflife at moderate temperature and the possibility to perform rehydration at any desired level. The application of this technique in the development of a Freeze dried mango milk shake powder using Badami mango (Mangifera indica L) pulp, milk (3.0g/100g fat, 8.5g/100g Solids Non Fat), nuts, flavourants and ascorbic acid to deliver RDA level of ascorbic acid and β-carotene was hence attempted. Optimized formulations were subjected to freeze drying for better storage stability. The water activity was found to be 0.22 and BET monolayer value 2.294g/100g solids. β-Carotene, ascorbic acid and oxidative rancidity profile monitored at ambient (28±2°C) and 37°C storage revealed no significant differences (p>0.01) at ambient temperature in ascorbic acid and thiobarbituric acid reactive substances (TBARS) but significant difference (p<0.01) was observed after storage at 37°C. Significant degradation of β-carotene was observed after 12 and 6 months of storage at ambient (28±2°C) and 37°C respectively. Total fatty acid profile by gas chromatography indicated the presence of saturated, monounsaturated and polyunsaturated fatty acids (PUFA) in the ratio of 1:0.51:0.28. PUFA like linoleic, linolenic and arachidonic were significantly (p<0.01) affected by 6 months of storage at 37°C. Organoleptically, the product was rated 7.60±0.10 and 7.49±0.09 under ambient and 37°C after 12 and 6 months storage respectively indicating good overall acceptability on a 9 point hedonic scale. ©2012 New Delhi Publishers. All rights reserved