Temporal changes in the physicochemical, textural and sensory attributes of butter fortified with vegetarian source of omega-3 fatty acid

Fortification of butter with omega-3 fatty acids and alpha linolenic acid results in higher level of unsaturated fatty acids. This may affect the oxidative stability of butter. Therefore, the present study was conducted to evaluate the impact of storage on the physico-chemical, textural and sensory attributes of the fortified butter samples packed in polypropylene cups and stored at 5 and -18 °C. The samples were analysed for 90 days with an interval of 15 days. During the storage, the samples were analysed for physico-chemical properties, oxidative stability, textural characteristics, sensory characteristics and microbial quality. Control sample showed higher (4.35 h) induction period than samples prepared by adding flaxseed oil (2.36 h) and flaxseed oil emulsion (2.56 h) as studied by rancimat. Peroxide value, free fatty acids and TBA value increased significantly (P<0.05) during storage however, the values were within the acceptable range. The optimized butter samples were examined for storage stability under refrigeration and frozen conditions for 90 days. Firmness, work of shear and yield stress increased slightly during the storage and samples stored at -18oC showed higher values than refrigerated storage. Even though, overall sensory acceptability decreased significantly (P<0.05) during the storage and the samples stored at -18oC showed higher score than refrigerated storage; it was still above 7.5 on 9 point hedonic scale. No microbial growth was observed throughout the storage period. Thus, it is concluded that omega-3 fatty acid fortification doesn’t adversely affect the storage stability of fortified butter and the butter has good sensorial acceptability and oxidative stability for 90 days of storage period.