Microstructure of breads on addition of the different types of fats and oils

摘要

The effects on addition of three kinds of fats and oils to doughs were investigated with baking quality and microstructure. Fats(H) consisted of hydrogenated fish oil and lard, a mixture(S) of fats and rapeseed oil and rapeseed oil(L) were added to doughs of breads, respectively. Specimens of doughs immediately after mixing, second fermentation and baked of breads were prefixed within 2.5% glutaraldehyde in a 0.05M phosphoric acid buffer (pH 7.4). After rinsed, each specimen was postfixed with 1% osmium tetraoxidate in the same buffer. Postfixed specimens were dehydrated by an ethanol series and then embedded within Spurru27s epoxy resin polymerized at 65℃ for 20 hr. After specimens were cut and stained, they were observed by optical and transmission electron microsocope. Breads mixing rapeseed oil had the lower loaf volume than those mixing two solids fats(S and H). The gluten strands in breads mixing rapeseed oil were unextended, and they contained a large number of lipid spheres. Microstructure of other breads were not observed any lipid spheres within the gluten strands.