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ThesisItem Open Access Functionality and stability assessment of fruit based dairy beverage(PAU, 2015) Shukla, Preeti; Bajwa, UshaThe present investigation was carried out to enhance the functional properties of mango based milk beverage through the generation of Maillard reaction products (MRPs) and assess its storage stability. Response Surface Methodology (RSM) was applied to optimize the level of milk fat, sugar and mango pulp in the beverage for responses of desirable viscosity, maximum antioxidant activity and high overall acceptability. The optimized levels were found to be 0.5 per cent milk fat, 6.0 per cent sugar and 30.0 per cent mango pulp. The beverage was packaged in HDPE sachets and glass bottles, sealed, pasteurized at 80°C for 5 sec and stored at 5.0°C. Also, the beverage was packaged in glass bottles, sterilized at 116°C for 15 min and stored at ambient temperature (25°C). The samples of beverages were evaluated for physicochemical, microbial and sensory quality at regular intervals. There was a significant (p<0.05) decrease in total solids, pH, ascorbic acid, reducing sugars, viscosity, antioxidant activity, HMF concentration and sensory scores and increase in total soluble solids and acidity during storage. Standard Plate Count (SPC) and Yeast and mold count of pasteurized beverages increased significantly (p<0.05) after ten days whereas sterilized beverage remained microbiologically stable even after 75 days of storage. The pasteurized beverage was acceptable up to six days whereas the sterilized one upto 60 days. To explore the role of milk proteins and sugar in MRP generation, simulated beverage samples were formulated using whey protein, casein and sugar in the concentration range from 0.0 to 1.0, 0.0 to 1.0 and 0.0 to 6.0 per cent, respectively. These were subjected to heat treatments varying from 63 to 121°C for 15s to 50 min. Antioxidant activity (as % inhibition of DPPH) and HMF as an index of MRPs generation, were determined at regular time interval during heat treatment. There was a significant (p<0.05) increase in the antioxidant activity and HMF concentration of samples at all the thermal treatments. The samples containing higher amounts of milk protein and sugar produced more MRPs and exhibited more antioxidant activity than control. The incorporation of mango further contributed to antioxidative components and enhanced the functional quality of the milk beverage.