Functionality and stability assessment of fruit based dairy beverage
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Date
2015
Authors
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Publisher
PAU
Abstract
The 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.
Description
Keywords
animal husbandry, beverages, antioxidants, organic compounds, productivity, fruits, vitamins, milk products, acidity, biological phenomena