Spray-Dried Gliadin Powders Inclusive of Linoleic Acid (Microcapsules): Their Preservability, Digestibility and Application to Bread Making

Abstract

An aqueous-alcohol solution containing gliadin (or zein) and linoleic acid was pulverized by spray-drying and the powders were examined for their stability, digestibility and application. Linoleic acid in the powders was kept stable during three months' storage in each case of low, moderate and high water activity. When the spray-dried powders were treated with such digestive enzymes as pepsin and pancreatin, linoleic acid was effectively changed into the hexane-extractable form concomitantly with the digestion of gliadin. The powders were administered to rats, instead of gluten and essential fatty acid in a semi-purified diet, and there was no abnormal excretion of fatty acid into the faeces. These facts indicate that two components of the powders could be digested and absorbed in the gut as usual. On the other hand, supplementation of bread with gliadin and linoleic acid in the form of spray-dried powders led to a considerable increase in bulk after baking, without affecting the taste and flavor. Linoleic acid in a loaf of bread seemed to be fairly resistant to peroxidation during baking in an oven and during storage under aerobic conditions for a week.