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Oat protein concentrate as alternative ingredient for non‐dairy yoghurt‐type product
Author(s) -
BrücknerGühmann Monika,
Vasil'eva Elena,
Culetu Alina,
Duta Denisa,
Sozer Nesli,
Drusch Stephan
Publication year - 2019
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.9858
Subject(s) - fermentation , food science , starch , ingredient , streptococcus thermophilus , chemistry , lactic acid , starter , proteolysis , lactobacillus , hydrolysis , biochemistry , bacteria , enzyme , biology , genetics
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 subjection to heat treatment to assure starch gelatinization. RESULTS In detail, the process of yoghurt production involved an initial heating step to 90 °C, 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 4.2) with a certain amount of lactic acid (3.3 ± 0.2 g kg −1 ) and contained 4.9 × 10 6 cfu g −1 lactobacillus after 24 h fermentation. Scanning electron microscopy revealed a porous network presumably built up from the gelatinized starch fraction containing aggregated structures, between which were assumed to be aggregated oat proteins. Moreover, to a limited extent, proteolysis occurred during fermentation. Thus some of the proteolytic enzymes 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. © 2019 Society of Chemical Industry