تحقیق آنتی اکسیدان 5 ( Anti oxidant )

تحقیق آنتی اکسیدان 5 ( Anti oxidant )

چکیده:

POLYPHENOL CONTENT AND ANTIOXIDANT ACTIVITY OF RYE BRAN EXTRUDATES PRODUCED AT VARYING PARAMETERS OF EXTRUSION PROCESS

ABSTRACT

Extrusion, a popular method of cereal processing, increases the amounts of phenolic acids in cereal grain. These compounds protect the human body from oxidation stress and prevent the development of chronic diseases. The present study determined the composition of phenolic acids in rye bran after extrusion and defined the antioxidant activity of the extrudates. The bran was obtained through the laboratory milling of the grain of three rye cultivars, namely Amilo, Rostockie and Agrikolo. Extrusion was performed in a single-screw laboratory extruder Brabender 20 DN equipped with a 3:1 screw and a 3 mm die. Screw speed was maintained at 190 rpm while two temperature profiles, 80-100-120°C and 120-160-180°C, were applied. Prior to extrusion, the moisture of the rye bran to be processed was equilibrated to 14 or 20%.

The main phenolic acid found in rye bran was ferulic acid. Irrespective of rye cultivar and the parameters of processing, the ferulic acid and diferulic acid contents increased two times, and the p-coumaric acid content increased by 70% due to extrusion. The levels of other phenolic acids and apigenin decreased or did not change. The exception was caffeic acid whose amount in extrudates was higher than in bran for the Amilo and Rostockie cultivars and was lower for Agrikolo. Using a 14% moisture of the original material and a temperature of 120 or 180°C as parameters of the extrusion process produced the highest antioxidant activity of rye bran extrudates. Key words: antioxidant activity, phenolic acids, rye bran extrudates.