Characterization of functional properties of oat protein and enrichment of kefir with oat protein

In this study, it was aimed to investigate the functional properties of oat protein, and to improve nutritional value of kefir by adding oat protein. For this purpose, water holding capacity, oil holding capacity, foaming properties, protein solubility and emulsion properties of oat protein were determined. Then, 0.5%, 1% and 2% (w/v) oat protein and 30% (w/v) kefir grains were added to cow's milk to produce four different types of kefir and physicochemical, sensory and microbiological properties of kefir were examined. Oat protein added to kefir had a significant effect on pH, titration acidity, serum separation, viscosity and total phenolic substance values and amount of Lactococcus depending on protein concentration (p<0.05). During the storage period, an increase was observed in the titration acidity, viscosity and total phenolic substance values of the kefir samples. Addition of oat protein reduced serum separation. Minimum serum separation was observed at 2% oat protein concentration. Addition of oat protein to kefir has been shown to promote the replication of Lactococcus. At the end of storage, the amount of lactic acid bacteria increased in kefir with 1% oat protein concentration. According to the results, it was observed that the addition of oat protein increased the amount of Lactococcus of kefir, improved its physicochemical properties and did not adversely change its sensory properties. Based on the data obtained, it has been concluded that adding oat protein can give kefir a functional property, and considering the sensory properties, it can be recommended to use 2% oat protein in kefir production.