Sachdev, Poonam AAnkit Kumar2022-02-042022-02-042021Ankit 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 Impact of different preservation techniques on the quality and shelf-life stability of melon-based smoothies (Unpublished M.Sc.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.https://krishikosh.egranth.ac.in/handle/1/5810181690Melons 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.EnglishThesis