Improving the extractability of arabinoxylans and the molecular weight of wheat endosperm using extrusion processing

Abstract

Cereal derived arabinoxylans (AXs) are non-starch polysaccharides that have immunomodulatory activities. These activities are thought to be related to the low molecular weight fractions of AXs. Wheat and wheat by-products are rich in AXs, however, the water extractable fraction of AXs in wheat products is low. Water extraction of AXs can be improved by extrusion processing, which increases the extractability of the water soluble fraction. The aim of this study was to determine the extractability and molecular weight of the water soluble fraction of AXs from wheat endosperm after extrusion at screw speeds of 80 and 160 rpm. Extrusion processing significantly (P<0.05) increased the water extractability of AXs in a screw-speed dependent manner (13.07±0.12% at 80 rpm and 15.45±0.16% at 160 rpm compared to8.95±0.10% in the non-extruded control) due to a significant increase (P<0.05) in low molecular weight fractions of AXs in extruded samples.

Effects of Co-Modification by Extrusion and Enzymatic Hydrolysis on Physicochemical Properties of Black Wheat Bran and Its Prebiotic Potential

“…Different from other parameters, with the increase in screw speed from 13 Hz to 15 Hz ( Figure 1 d), the content of WEAX increased slightly from 1.84 g/100 g to 1.99 g/100 g ( p < 0.05), while there was a decrease to 0.88 g/100 g when screw speed increased to 17 Hz. This is different from the result of Fadel et al, who reported a tendency for WEAX content in defatted rice bran to increase with extrusion screw speed from 80 rpm to 160 rpm [ 6 ]. A higher extrusion speed will exert high shear force to liberate ferulic acid side chains esterified to AX residues, which might induce higher exposure of AX to water, thus increasing WEAX content [ 51 ].…”

“…Arabinoxylan (AX) is the main DF in WB, accounting for over 50% of total dietary fiber (TDF) [ 6 ]. However, most AXs are embedded in the cell wall matrix and intertwined with other macromolecules, which makes them difficult to extract with water [ 7 ].…”

The effect of extrusion screw speeds on molecular weight and immune responses of water soluble arabinoxylans from rice bran

“…Arabinoxylans (AXs) are major non-starch polysaccharides (NSPs) in cereals. AXs have attracted attention due to their immunomodulatory activities (1) , which may be related to the content of low molecular weight (Mw, < 32 kDa) AXs, (1) . Rice bran (RB) is a rich source of AXs (1) but water extraction of RB AXs is difficult giving a low yield.…”

Advances on the Valorisation and Functionalization of By-Products and Wastes from Cereal-Based Processing Industry

“…It was hypothesized that extrusion cooking increases dietary fibre solubility, probably due to the reduction in particle sizes of extruded samples [87] and/or the breaking down of covalent and non-covalent bonds in larger molecules due to the high temperature applied [88]. It was reported that extrusion of rice bran increases the extractable levels of AXs but decreases the A/X ratio and molecular weight compared with non-extruded samples [80,89]. Such an effect is likely to be owing to the high shear-stress forces and high temperatures applied that can cause the release of ferulic acid, softening of lignin and AXs depolymerization.…”

“…Arabinoxylans Fermentation [102][103][104] Ultrasonic/microwave [105,106] Enzymatic treatment [107][108][109][110] Milling fractions [111][112][113] Alkaline treatment [114][115][116][117] Nixtamalization [118] Starch removal [119] Extrusion [80,86,89,120] Subcritical water treatment [119,121] β-glucans Ultrasound [122] Roller-milling/pearling [123] Milling [124][125][126] Fermentation [127,128] Enzymatic treatment [129,130] Extrusion [131][132][133][134] Subcritical water treatment [119,135,136]…”