EFFECTS OF FATTY-ACID SPECIES OF MONOGLYC ERIDE ON BREADMAKING PROPERTIES

Effects of monoglyceride on breadmaking properties were investigated b y employing three types of monoglycerides: glyceryl monostearate (GMS) as saturated monoglyceride, glyceryl monooleate (GMO) as cis-unsatura ted monoglyceride and glyceryl monoelaidate (GME) as trans-unsaturated monoglyceride. Polymorphism of monoglycerides, which was considered a s a factor of their dispersibility in an aqueous solution, was first e xamined by using X-ray diffraction and DSC analysis. In GMS and GMO, s table crystal state remained during storage at 20 degrees C, and in GM E unstable crystal state was easily transformed to stable one. The uns table crystal of GME was considered to improve its dispersibility in d ough as well as in the aqueous solution. The characteristics of dough with or without addition of these monoglycerides were investigated by Farinograph and Extensigraph. Breadmaking were tested according to 70% sponge-dough procedure method. Each monoglyceride was added in dough less than 1% on flour weight basis. The dough consistency decreased de finitely during mixing, and the dough strength to extension increased by the addition of GMO or GME. The loaf volume increased by the additi on of GMO or GME. These effects were not shown by the addition of GMS. The change in crumb firmness during storage was depressed by the addi tion of GMS or GME, providing a softer bread. In order to elucidate a mechanism of dough improvement, the added monoglycerides were extracte d from dough much more. GMO and GME were located in the gluten fractio n than GMS. It suggested that the double bonds of unsaturated monoglyc erides were bound easily to the gluten fraction, so that the amount of monoglycerides in the gluten fraction influenced the dough characteri stics.