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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., (© 2019 Society of Chemical Industry.)

Foods with increased protein content have rapidly become one of the fastest-growing product categories targeting image- and health-focused consumers. However, it is not clear whether consumers really understand the difference between 'inherently rich in protein' and 'artificially increased protein'. This study used a qualitative focus group approach to investigate the consumer preferences and perceptions of foods with increased protein content among mixed-age and older population in four European countries. In total fifty-two participants were involved in the study. Understanding of the concept of foods with 'increased protein' content was limited. Both older and mixed-age participants could not differentiate between natural sources of protein and foods with increased protein content, no matter whether foods with animal or plant proteins were mentioned. Older participants expressed more scepticism towards foods with increased protein content than mixed-age participants. The combination of protein type and food carrier closer to conventional foods received more acceptance among both older and mixed-age participants. Future use and acceptance of foods with increased protein content will depend on the extent to which consumer concerns about incorporating additional protein into a diet can be responded., (Copyright © 2018 Elsevier Ltd. All rights reserved.)