Investigation about production possibilities of probiotic yoghurt with apricot kernel milk and optimization studies

In the study, reasons such as vegan-vegetarian type nutrition, special dietary needs, lactose intolerance, cow's milk allergy, as well as the possibilities of producing probiotic yogurt from apricot kernel milk for sustainable food production and transformation of apricot kernels into value-added products were investigated. Apricot kernel milk ratio, transglutaminase enzyme amount and storage time independent variables in yogurt content were optimized by response surface method. Optimization was achieved by examining the responses of these independent variables to acidity, water holding capacity, ACE-inhibition and sensory analysis. It was determined that the optimum point occurred in the probiotic yogurt sample with 20% apricot kernel milk and 0.9% transglutaminase content on the 7th storage day. These conditions, which were determined by the Response Surface Method, were tested with experimental data and the estimated results were confirmed. The presence of volatile components in the apricot kernel milk produced at the optimum point was determined by GC-MS on the 7th day of storage. In addition, physicochemical, microbiological, antioxidant activity, ACE-inhibition and sensory analyzes were performed on the 1st, 7th, 14th, 21st and 28th days of storage in order to see the effect of storage time on apricot kernel milk fortified yoghurt sample. When the aroma profile of the apricot kernel milk fortified probiotic yogurt sample produced at the optimum point was examined, it was found that it differed from cow's milk probiotic yogurt with limonane, benzaldehyde, benzyl alcohol and benzylhydrazine flavorings.The ACE-inhibition value, which was in the range of 66.09-89.48% in the control sample, was found to be higher as 76.63-92.41% in the probiotic yogurt sample with the addition of apricot kernel milk. Similarly, the IC50 value was found in the range of 30,33-46,12 mg/L in the yogurt sample with apricot kernel milk, while it was found in the range of 27,89-42,78mg/L in the control yogurt. In addition, the number of probiotic organisms was determined at a desirable level during the storage period in both of the yoghurt samples. The similarities in the physicochemical, microbiological and bioactivity analyzes of the yogurt samples during the storage period, as well as the positive sensory evaluation results, showed that probiotic yogurt with apricot kernel milk added could be consumed as an alternative dairy product to cow's milk probiotic yogurt.