THE EFFECT ON SENSORY PREFERENCES AND FUNCTIONAL CHARACTERISTICS OF FERMENTED MILK BEVERAGES ENHANCED WITH DIFFERENT PROTEIN ADDITIVES
Project no. 897 · Status: Kapanmış · 2018
Summary
In the study, both the sensory preferences of the consumers and the functional properties of the product were investigated by enriching the fermented milk beverages with whey proteins, casein and skim milk powder, which are natural components of milk. The pH, titration acidity, dry matter, protein, fat and ash values of the samples were found to be compatible with the relevant articles of the Turkish Food Codex, Communiqué No. 2009/25 on Fermented Milk and similar studies. While no serum separation was observed in the KAZ sample in kefir during storage, the highest serum separation was observed in the KAZ sample in the ayran samples. This situation is associated with the amount of salt used in ayran production. Except for the kefir KAZ sample, a significant (p?0.05) increase was observed in serum separation values during storage. Among both kefir and ayran samples, the highest L* value among the color values was measured in the PAS sample. It was determined that there was a significant (p?0.05) difference between the a* values of the samples. pH values for kefir and ayran samples were determined as 4.48-4.28 and 4.41-4.11, respectively. Titration acidity values for calculating %LA values were reported as 0.8685-0.9900 and 0.5342-0.7931 for kefir and ayran, respectively. In vitro digestion model was applied to kefir and ayran samples developed in the study. Pre-digestion %ACE inhibition values ranged from 78.63 to 90.30%. It was determined that the %ACE inhibition values of the control sample remained at the lowest level at all stages of digestion and the difference between the K sample and the protein-rich samples was significant (p?0.05). Antioxidant activity value, which varied between 0.3615-0.5512 before digestion, was found to be 1.3796-1.9313 after gastrointestinal digestion (p?0.05). In kefir samples, Lactobacillus spp., Lactococcus spp, yeast amounts varied in the range of 5.43-7.77 cfu/ml, 8.79 – 11.05 log cfu/ml, 2.45 – 7.78 log cfu/ml, respectively. Lactobacillus spp. level 5.00-8.26 log cfu/ml, Streptococcus spp. level varied between 8.01-10.58 log cfu/ml. When the R2, ?², RMSE values of the kefir samples were examined, the KAZ sample conformed to the Herschel-Bulkley model, while the K, YST, PAS and MIX samples fit the Exponential model. In the ayran samples, the PAS sample was found to fit the Herschel-Bulkley model, while the K, YST, KAZ and MIX samples were found to be fit to the Exponential model. It was determined that the consistency coefficient and apparent viscosity values of KAZ and MIX samples with high casein content were significantly (p?0.05) higher than those of K, YST and Whey samples. In the descriptive sensory analysis, it was observed that there were fluctuations in flavor and flavor components for kefir samples during 28 days of storage. It was determined that there was an increase in animal flavor in KAZ samples, and an increase in creamy flavor in PAS added samples. The salty taste value of the ayran samples was found to be statistically different (p?0.05) in the PAS sample at the end of storage. In the consumer test, taste, consistency, general taste, saturation and snack preferences were evaluated. For all the questions directed to the consumer, the MIX sample was preferred the most among the kefir samples. Whey sample was preferred the most in terms of taste, consistency and general taste in ayran samples, and KAZ sample was preferred in terms of saturation and snack choice. Protein-rich samples were statistically different from the control sample (p?0.05) in both kefir and ayran samples. As a result, considering the increasing trend of healthy eating and the therapeutic effects in fermented products, it has been seen that a total of 8 nutrition claims can be made on the label, including 4 kefir and 4 ayran with increased protein content for the most preferred fermented beverages in our country. In the developed samples, it was determined that there was an increase in %ACE inhibition activity and Antioxidant activity capacity. In the light of these results, it can be said that protein-rich fermented beverages will contribute to a healthy diet model due to their health-supporting effects. In addition, it is thought that the data obtained from the physicochemical, microbiological, rheological and sensory analyzes carried out in the study will shed light on sectoral research and development studies for the production of protein-rich kefir and ayran.