Sangita GangulyPATEL DHARMIK2023-12-062023-12-062022https://krishikosh.egranth.ac.in/handle/1/5810202257Ricotta is a soft, mild- flavored, unripened variety of whey cheese. Ricotta is a protein coprecipitate having high moisture content. Ricotta has a short shelf life due to its inherent quality like high moisture and low salt content. Attempts had been made previously to develop pHbased freshness indicator for Ricotta cheese which could not be successful. Therefore, present research work was undertaken to develop safe and ready to use chemo-responsive dye-based freshness indicator to monitor quality of buffalo milk Ricotta cheese. Initially, Ricotta cheese was stored in PET and glass jar at 5±1°C and changes in physico-chemical, sensory and microbial attributes were monitored. Moisture, water activity, pH sensory scores were significantly (p<0.05) decreased whereas acidity, TVB-N, standard plate count, yeast and mould count significantly (p<0.05) increased during storage of Ricotta cheese at 5±1°C. After 12 days, buffalo milk Ricotta cheese was unacceptable in terms of sensory and microbiological quality. No significant difference (p<0.05) was observed for physico-chemical, sensorial and microbiological changes of Ricotta cheese during storage packaged in two different packaging materials viz., PET and glass jar. To fabricate chemo-responsive dye-based freshness indicator for Ricotta cheese, preliminary trials were conducted using natural pigment (anthocyanin) based freshness indicator but colorimetric changes observed were statistically non-significant (p<0.05) for stored Ricotta samples. Subsequently, trials were conducted to standardize preparation protocols for ready to use freshness indicators using 3 different synthetic dyes. Based on the results obtained, suitable dye was selected for indicator fabrication. Suitable carrier materials were optimized to immobilize the selected dyes to form gel strips. During storage conditions i.e. 5±1°C, selected indicator labels (M1 and M2) were attached inside the storage containers of buffalo milk Ricotta cheese for their real time performance evaluation and estimation. It was found that the yellowness index of both indicator labels was positively correlated with color change, titratable acidity, standard plate count, yeast and mould and coliform count content while it was negatively correlated with the pH of Ricotta cheese. Regression equation was developed to estimate the relationship of indicator label response in terms of ΔE with suitable parameters. It can be concluded that the freshness indicator labels could be successfully developed for monitoring in-package quality of Ricotta cheese. Total volatile base nitrogen and ammonia may be considered as main responsible component for changing color of developed freshness indicator.EnglishThesis