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Kerala Veterinary and Animal Sciences University, Wayanad

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20221
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Subject: Dairy Chemistry × Author: AISWARYA V G × Thesis Type: M.Tech. ×
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    ThesisItemOpen Access
    EFFECT OF DIFFERENTIAL HEAT TREATMENTS ON BIOFUNCTIONAL PROPERTIES OF BIOPEPTIDES IN FERMENTED GOAT MILK
    (VERGHESE KURIEN INSTITUTE OF DAIRY AND FOOD TECHNOLOGY MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2022-12-20) AISWARYA V G; Dr. Rachana C.R
    Goat milk, which is claimed to have medicinal value, is one of the naturally occurring functional foods and is generally used as a substitute for human milk. However, goat milk proteins are more sensitive to heat treatment, and no data are available in the literature about the impact of thermal processing on biopeptides. Therefore, in the present study, the effect of differential heat treatments on the biofunctional properties of biopeptides in fermented goat milk was investigated. Three heat treatments were used in the analysis namely, 72°C/15sec, 85°C/10min, and 121°C/15min. The physicochemical analysis of this differentially heat-treated goat milk showed that protein content and lactose content of milk heated to 121°C/15min were significantly lower. The pH of milk decreased significantly with heating to around 6.25 in the case of milk heated to 121°C/15min. Antioxidant activity was highest in milk heated to 121°C/15min with an average of 51.18% RSA. Milk heated to 85°C/10min showed 35.47% inhibition of the ACE enzyme. Antimicrobial activity was observed against E.coli in the case of 85°C/10min. SDS-PAGE was used to compare protein fragments. Seven bands that were clearly visible on the electrophoretogram of raw milk showed disappearance with the intensity of heating. The fermentation and subsequent storage analysis on the 0th, 7th, 14th, and 21st day showed that both biofunctional and physicochemical property was significantly changed. The pH and carbohydrate content gradually decreased while acidity gradually increased with the storage period. Antioxidant activity was highest in fermented milk initially heated to 121°C/15min, which showed 70.20% RSA on the 21st day. Antihypertensive activity and antimicrobial activity were highest in fermented milk initially heated to 85°C/10min. Protein profiling in all three cases of fermentation showed that as storage time rose, the intensity of the β-Lg band in samples decreased. By the sensory evaluation of fermented product from three heat treatments, it was found that fermented product made from milk initially heated to 121°C/15min had better organoleptic properties and a pleasant flavour. It may be inferred that the biofunctional properties can be changed with suitable heat treatment and fermentation, which will help produce milk products with improved sensory qualities that are hypoallergenic