Composition and microstructure alteration of triticale grain surface after processing by enzymes of cellulase complex

Elena Kuznetsova,Jan Brindza,Maria Mertvischeva,Svetlana Motyleva,Vladislav Zomitev

doi:10.5219/411

Abstract

It is found that the pericarp tissue of grain have considerable strength and stiffness, that has an adverse effect on quality of whole-grain bread. Thereby, there exists the need for preliminary chemical and biochemical processing of durable cell walls before industrial use. Increasingly used in the production of bread finds an artificial hybrid of the traditional grain crops of wheat and rye - triticale, grain which has high nutritional value. The purpose of this research was to evaluate the influence of cellulose complex (Penicillium canescens) enzymes on composition and microstructure alteration of triticale grain surface, for grain used in baking. Triticale grain was processed by cellulolytic enzyme preparations with different composition (producer is Penicillium canescens). During experiment it is found that triticale grain processing by enzymes of cellulase complex leads to an increase in the content of water-soluble pentosans by 36.3 - 39.2%. The total amount of low molecular sugars increased by 3.8 - 10.5 %. Studies show that under the influence of enzymes the microstructure of the triticale grain surface is changing. Microphotographs characterizing grain surface structure alteration in dynamic (every 2 hours) during 10 hours of substrate hydrolysis are shown. It is found that the depth and direction of destruction process for non-starch polysaccharides of grain integument are determined by the composition of the enzyme complex preparation and duration of exposure. It is found, that xylanase involved in the modification of hemicelluloses fiber having both longitudinal and radial orientation. Hydrolysis of non-starch polysaccharides from grain shells led to increase of antioxidant activity. Ferulic acid was identified in alcoholic extract of triticale grain after enzymatic hydrolysis under the influence of complex preparation containing cellulase, xylanase and β-glucanase. Grain processing by independent enzymes containing in complex preparation (xylanase and β-glucanase) shows that more significant role in polysaccharide complex composition and grain surface microstructure alteration belongs to xylanase. Grain processing by independent of cellulolytic enzymes may decrease the strength of pericarp tissue of grain and improved sensory characteristics of the bread.

Highlights

Dietary fiber in cereals is presented by non-starch polysaccharides found in the cell walls and consisting mainly of arabinoxylan and β-glucan (Jacobs et al, 1998; Gebruers et al, 2008)
Processing of grain by individual enzymes like hemicellulase comprised in complex preparation, showed that more significant role in polysaccharide complex composition of grain surface structures alteration belongs to xylanase
During experiment it is found that triticale grain processing by enzymes of cellulase complex leads to an increase in the content of water-soluble pentosans by 36.3 – 39.2% and carbohydrates with a low molecular weight and high solubility

Summary

Introduction

Dietary fiber in cereals is presented by non-starch polysaccharides found in the cell walls and consisting mainly of arabinoxylan and β-glucan (Jacobs et al, 1998; Gebruers et al, 2008). Total dietary fiber content of triticale grain is 13 – 16 % depending on the sort. Studies show that the molecular structure and the structural organization of arabinoxylans and β-glucans of grain (pentosans) are important determinants of their physical properties, such as solubility in water, viscosity, digestibility. This determines the functionality of said polysaccharides and their physiological functions in the gastrointestinal tract of humans (Vaikousi et al, 2004; Lazaridou et al, 2007). Inclusion of cereals products containing dietary fiber in diet helps reduce cholesterol concentration, that decrease the risk of coronary heart disease (McIntosh et al, 1991; Brown et al, 1999), improve the glycemic level control for people with type II diabetes (Lu et al, 2004), increases intestinal peristalsis (Cummings et al, 1992, 2009)

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