Borpuzari, TrishnaSaikia, Rashmi Rekha2023-12-212023-12-212022https://krishikosh.egranth.ac.in/handle/1/5810204105A study was conducted to develop flavour and colour enhanced cow’s milk ghee using starter cultures as a source of microbial enzymes and phytochemicals of bael (Aegle marmelos) fruit pulp extract. The experiment was conducted in the laboratories of the Department of Livestock Products Technology, the All India Coordinated Research Project on Post-Harvest Engineering and Technology, the Department of Livestock Production and Management, the Department of Veterinary Biochemistry, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati–781 022; and the Central Analytical Instrumentation Facility, Guwahati Biotech Park Incubation Centre of the Indian Institute of Technology, Amingaon, Kamrup, Guwahati-781 031 during the period from August 2020 to April 2022. Lactococcus lactis ssp. lactis var. diacetylactis and yoghurt cultures of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were used @ 3% (v/v) in the study. Bael pulp extract was added @ 1% (v/v) to the treatment groups. Cow’s milk ghee was prepared by the heat clarification method. The flavour and colour qualities, FFA contents, antioxidant compounds, sensory attributes, proximate composition and shelf-life of the cow’s milk ghee thus prepared were studied. The ghee was stored at ambient temperature to study the shelf-life. A total of 34 flavour compounds were detected in the samples of the treatment groups as well as the reference sample by GC-MS studies. Identical numbers of FFA were also detected in the ghee samples. The flavour of the ghee was attributed by the FFA along with the other flavouring compounds like the alcohol, hydrocarbons, ketones, terpenoids, organic acids and 9 other compounds identified in the ghee samples. Ascorbic acid, thymol, phytol and β-sitosterol were the four antioxidant compounds detected by GC-MS. The maximum radical scavenging activity (60.160±0.541%) was observed in the sample of T4. Bael pulp extract added ghee samples had higher DPPH inhibition activity as compared to the other groups and the reference sample. Colour component b* was found in higher values in bael pulp extract added ghee samples. Highly significant positive correlation was found between the sensory evaluation scores for colour and the colorimetric assessment of the colour components (b* value). Higher panel ratings for flavour and colour of the samples of T4 group indicated that bael pulp extract indeed had a positive effect on the flavour and the colour characteristics of cow’s milk ghee. The moisture and ash contents of the ghee were highly significantly influenced by the starter cultures and addition of bael pulp extract while only significant difference could be found in their protein content. Shelf-life study was done based on the FFA and peroxide values. Correlation studies revealed a highly significant difference between FFA and PV while a negative correlation existed between the FFA x antioxidant activity and PV. A gradual increase in FFA and PV along with the increase during the storage period was found in all the treatment groups. Even after 6mon of storage, FFA and PV were found to be much lower than those recommended by the FSSAI (2016). From the study it was found that the starter culture Lc. lactis ssp. lactis biovar diacetylactis used in the study in combination with the bael pulp extract produced cow’s milk ghee with improved flavour and colour attributes and had an extended shelf-life at room temperature.EnglishThesis