Changes in Physico-Chemical and Sensory Characteristics of Concentrated Yogurt Made from Goat Milk during Storage

Abstract

The objective of the study was to evaluate the changes in physico-chemical and sensory characteristics of concentrated yogurt made from goat milk during storage. Fresh milk of Peranakan Etawah goats was processed into stirred-type fresh yogurt by adding probiotic yogurt cultures. Yogurt was processed into concentrated yogurt using in-bag straining method, cut into blocks, immersed in different vegetable oils (olive, corn, canola and sun ower oils) in capped jars, then stored for up to 30 days under cool temperature. Variables observed consisted of super cial growth of yeast, changes in color, off- avour, consistency, pH and titratable acidity. Results showed that pH and titratable acidity tended to increase during storage, but the differences were not signi cant among different immersing oils. No apparent growth of super cial yeast, changes in color and consistency were detected in concentrated yogurt up to day 30 of storage. However, a slight off- avour was detected at day 30 which could be due to rancidity of oils. It can be concluded that shelf-life of concentrated yogurt can be extended by immersing in vegetable oils, and the decision of which oils to use will depend on the price and local availability.