Investigations on aroma profile of artisanal yoghurt starter cultyres

Abstract

Yoghurt is an important fermented milk product that is consumed widely around the world as a part of the diet. Yoghurt is produced by lactic acid fermentation using Streptococcus thermophilus, and Lactobacillus delbrueckii ssp. bulgaricus. The most important criteria in yoghurt production are the selection of artisanal yoghurt starter cultures to achieve the typical aroma and quality of the final product. The typical aroma of yoghurt is identified chiefly by acetaldehyde that is the most important for yoghurt aroma. The aim of this study is to determine artisanal yoghurt starter cultures that provide the most desirable aroma to yoghurt, in order to promote industrial production with such flavor. In the first part of this study, the influence of different aroma cultures addition on the aroma production properties in yoghurt products was investigated. Nine different aroma cultures were added into the starter culture combinations at two different inoculation ratios. Among all of the combinations, just one yoghurt combination was selected according to the highest acetaldehyde and also the highest sensory scores. According to the results, two batches of yoghurt were produced: Sample 1 containing only yoghurt starter cultures (Lactobacillus bulgaricus Y30 + Streptococcus thermophilus Y24), was used as control yoghurt; Sample 2 containing yoghurt starter cultures plus with selected aroma culture (P10), was used as yoghurt with aroma culture. Yoghurt samples were stored at 4 °C for 21 days. The pH, titratable acidity, total solids, fat, protein, syneresis, viscosity, aroma profile, lactic acid and lactose profile, proteolytic activity, microbiological characteristics and sensory characteristics