Quality Evaluation of Avocado (Persea americana) Fruit Yoghurt Made from Buffalo Milk

Abstract

Buffalo milk is well suited for the development of processed dairy products due to the high content of total solids. Yoghurt is a fermented dairy product obtained from milk fermented by lactic acid bacteria. Incorporation of fruits with yoghurt may increase the nutritional value and consumer acceptability. This research was designed to develop avocado incorporated buffalo milk yoghurt with high consumer acceptability. Yoghurt samples were prepared with different percentages of avocado puree as follows: 0% (control), 5% , 10% and 15% . Best level of avocado puree was determined by a sensory evaluation with fifteen semi trained panellists using five point hedonic scale. Titratable acidity (% ), pH, syneresis (% ), water holding capacity (% ) and coliform, yeast and mould counts of the yoghurts were assessed during the storage (5°C, 4 weeks). Results of the sensory evaluation revealed that 10% avocado incorporated yoghurts were significantly {p<0.05) preferred over other groups by the panellists. During storage, pH and titratable acidity of 10% avocado yoghurts were varied from 4.38±0.02 to 3.72±0.03 and 0.93±0.15% to 1.80±0.10% , respectively. No coliform counts were observed in any of the yoghurt samples. Yeast and mould counts were higher in 10% avocado incorporated yoghurts than the control. The appearance of yoghurt from control was not promising after three weeks of storage. Incorporation of 10% avocado puree into yoghurt is possible and the product can be stored for two weeks in refrigerated condition while buffalo milk yoghurt without avocado can be stored for three weeks without major quality deterioration.