Impact of different preservation techniques on the quality and shelf-life stability of melon-based smoothies
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Date
2021
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Punjab Agricultural University, Ludhiana
Abstract
Melons are rich source of phytonutrients and contain a huge amount of water but due to
limited seasonal availability of melons in India, there is a need to process melons into
valuable shelf stable products and to also ease up the cumbersome method of cutting and
consuming melons by making value added products with wholesomeness of fruit. Present
investigation was carried out with an aim to formulate smoothies with melons, study the
effect of different processing treatments and storage period on the smoothie. Different
combinations of smoothies were formulized using watermelon, cantaloupes, cucumber,
lemon, gum tragacanth and extract of ginger, mint and basils. On the basis of sensory
evaluation and visual separation, smoothie combinations with watermelon 80% and
cantaloupe 20% with lemon concentration of 3.5% and gum concentration of 0.50% were
selected. Addition of lemon dropped the pH of samples from 6.22 to 4.40 which imparts
preservation effect to the smoothies. Further, three bioactive extracts were added to smoothies
to enhance the sensory properties, phytochemical composition and to control the microbial
count in the product. Thereafter, three processing treatments were given to the smoothies i.e.
refrigeration at 4 oC, pasteurization at 80 oC and then subsequent storage at 4 oC; and
sterilization at 100 oC with storage at ambient temperature. Effect of thermal treatments on
physico-chemical, phytochemical, optical and sensory properties of different smoothies was
studied during the investigation. A significant reduction in phytochemical composition and
sensory evaluation scores of heat-treated smoothies was observed. However, pasteurization
treatments enhanced total carotenoids and polyphenolic content; and stabilized the viscosity
of smoothies. Storage studies of the samples were also carried out and samples were analysed
for different parameters like TSS, ash, total sugars, pH, colour, titrable acidity, reducing
sugars, viscosity, total phenolic content, total carotenoids, percent transmittance ascorbic acid
and antioxidant activity during the storage period. Smoothie with mint along with ginger
extract (T6) was efficient in controlling microbial count as compared other extracts during the
storage period. Maximum storage stability was observed for pasteurized smoothies (30 days)
followed by sterilized (15 days) and Refrigerated smoothies (7 days). Hence, the present
study gives a scope regarding innovative valorisation of melons into shelf stable products.
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Citation
Ankit Kumar (2021). Impact of different preservation techniques on the quality and shelf-life stability of melon-based smoothies (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.