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Oat protein concentrate as alternative ingredient for non‐dairy yoghurt‐type product

Brückner-Gühmann, Monika; Vasil'eva, Elena; Culetu, Alina; Duta, Denisa; Sozer, Nesli; Drusch, Stephan

BACKGROUND: During the industrial production of β-glucan, a protein-rich fraction remains as a by-product. Recovery of this protein as oat protein concentrate (OPC) results in a source of cereal protein for food and improves the overall economy of the process. In this study, a yoghurt-type product is developed by lactic acid fermentation of an OPC suspension after subjecting to heat treatment to assure starch gelatinization. RESULTS: In detail, the process of yoghurt production involved an initial heating step to 90 °C, subsequently followed by 24 h fermentation with a starter culture consisting of Lactobacillus delbrueckii subsp. bulgaricus und Streptococcus thermophilus. The resulting yoghurt-type product was mildly sour (pH-value 4.2) with a certain amount of lactic acid (3.3±0.2 g kg-1) and contained 4.9∙106 cfu g-1 of lactobacillus after 24 h of fermentation. SEM revealed a porous network presumably built up from the gelatinized starch fraction containing aggregated structures in-between which were assumed to be aggregated oat proteins. Moreover, to a limited extent, proteolysis occurred during fermentation. Thus, some of the proteolytic enzymes being present in the yoghurt culture cleaved oat protein and released peptides. However, the effect on essential amino acids was small. CONCLUSION: The results of this study provide a deeper knowledge into the role of starch and protein in fermented OPC yoghurts. The structure of fermented OPC verifies the applicability of oat protein as an alternative source for yoghurt-type products.
Published in: Journal of the Science of Food and Agriculture, 10.1002/jsfa.9858, Wiley