Improvement of nutritional and bioactive properties of barleyb-glucan-based food products usingBacillus subtilis168endo-b-1,3-1,4-glucanase

Abstract

The combination ofb-oligosaccharides from enzymatically hydrolysed barleyb-glucan has attracted inter-est recently due to its positive effects on human health. This study aimed to assess the impact of theendo-b-1,3-1,4-glucanase enzyme fromBacillus subtilis168 on improving the nutritional and bioactiveproperties of barleyb-glucan. A new procedure for the isolation ofb-glucan was developed, at a lowertemperature (45°C), enabling purity from starch contamination, without affecting the yield (6 gb-glucanfrom 100 g of barley flour). The endo-b-1,3-1,4-glucanase is cloned intoE. colipQE_Ek enables the highproduction and purification (82% yield, 1.8 mg mL 1and 440 U mg 1) of an enzyme identical to thenatural one (25.5 kDa). The enzymatic reaction showed high efficiency ofb-glucan degradation by recom-binant enzyme, giving a mixture of products (of which 3-O-b-cellobiosyl-D-glucose and 3-O-b-cellotriosyl-D-glucose are the most abundant), the reduction of viscosity (17%) and increase in antioxidant capacitiesby 15.2%, 30.9% and 44.0% assessed by ABTS, DPPH and ORAC, respectively. These results indicatethe possible application of endo-b-1,3-1,4-glucanase enzyme in improving the properties of barleyb-glucan used as functional foods.