• Autio, Karin
• Poutanen, Kaisa
• Lille, Martina
• Salmenkallio-Marttila, Marjatta
• Myllymäki, Olavi
• Heiniö, Raija-Liisa

Abstract

This study is a part of a larger project aiming to produce new, healthy,and tasty food ingredients from oat. Germination and different heatingprocesses can be used to improve the texture and flavour of cereals. In thisstudy effects of germination and wet and dry heating on the microstructure,instrumental structure and sensory properties of two oat varieties wereassessed. The microstructure of native, germinated, autoclaved and extrudedgrains of the hulled cv. Veli and hull-less cv. Lisbeth was examined by lightmicroscopy, the texture was measured by determining the milling energy andhardness of the grains and sensory characteristics were evaluated withdescriptive sensory profile analysis. In cv. Veli the cells of the starchyendosperm were smaller than in cv. Lisbeth and beta-glucan was concentrated inthe subaleurone layer. In cv. Lisbeth beta-glucan was evenly distributed inthe starchy endosperm. The grains of cv. Lisbeth were more extensivelymodified in the germination process than the grains of cv. Veli, otherwise theeffects of processing on the grains of the two cultivars were similar.Germination caused cell wall degradation, autoclaving and extrusion cookingcaused starch gelatinization. Autoclaving resulted in the hardest perceivedtexture in oat. Gelatinization of starch appeared to contribute more to thehardness of oat groats than the cell wall structure. Of the instrumentalmethods used in this study the milling energy measurement appeared to be themost useful method for the analysis of the effects of processing on grainstructure.

Topics

• impedance spectroscopy
• grain
• grinding
• extrusion
• laser emission spectroscopy
• milling
• texture
• autoclaving