The effect of polyphenol oxidase on the physicochemical properties of flour types produced from some varieties of Syrian soft wheat

Abstract

In this research, the production of flour types with specific extraction rates (70%, 80%, 90% and 100%) from some varieties of Syrian soft wheat (Doma2, Douma4, Douma6, Cham4 and Cham 10) was carried out, and then the polyphenol oxidase activity was inhibited by adding ascorbic acid to flour, in order to study the effect of this enzyme activity on some physicochemical properties of the resulting flour, and to determine the optimal variety for bread making and the optimal extraction rate.

The analysis results showed a high content of moisture, ash, protein, acidity and colour with high extraction rates, but the inhibition of polyphenol oxidase led to an improvement in the colour of flour, especially at the low extraction rates of 70% and 80%.On the other hand, the acidity of the flour decreased after adding ascorbic acid, because in addition to inhibiting the PPO enzyme, it inhibited lipase, protease and phosphatase. The wet gluten content decreased at high extraction rates due to the high fiber content, which worked to break the gluten network, but the gluten content improved after inhibiting the PPO enzyme due to the absence of amino acid degradation and the preservation of the functional and structural properties of the proteins.The elasticity improved by increasing the extraction rate up to 80%, and then declined due to the regression of the gluten network. After inhibiting the PPO enzyme, the elasticity improved in most of the samples, but it remained relatively poor at the high extraction rates 90% and 100%.In general, the flour resulting from Cham10 outperformed the rest of the studied soft wheat cultivars, in terms of colour, gluten and elasticity, poor at the extraction rate 80%.