Improving the Yield of Feruloyl Oligosaccharides from Rice Bran through Enzymatic Extrusion and Its Mechanism

Abstract

Rice bran, rich in feruloyl arabinoxylan, is a good source of feruloyl oligosaccharides (FOs). To prepare FOs, bran was often hydrolyzed by amylase and protease to remove starch and protein and then hydrolyzed by xylanase, which was time-consuming and had a low yield. To solve the above problems, enzymatic extrusion was used to treat rice bran, and the effects of traditional hydrolysis, a combination of traditional extrusion and hydrolysis (extrusion-hydrolysis) and enzymatic extrusion on the yield of FOs were investigated and compared in this study. It was found that traditional extrusion and enzymatic extrusion significantly increased the yield of FOs. Particularly, the yield of FOs resulting from enzymatic extrusion was increased to 5.78%, while the yield from traditional hydrolysis was 4.23%. Microscopy analysis showed that extrusion damaged the cell wall of bran, which might increase the accessibility of xylanase to arabinoxylan and the yield of FOs. Spectroscopy analysis suggested that FOs obtained by different pretreatments had similar structures. It was obvious that enzymatic extrusion saved the time for removal of starch and protein and increased the yield of FOs. In addition, the highest yield of FOs was found at the moisture content of 30% and the screw speed of 50 rpm. This study provided an efficient method for the preparation of FOs that is suitable for industrial production.

Unlocking the potential of rice bran through extrusion: a systematic review

“…38 Additionally, extrusion damaged cell walls, making xylanase more available for arabinoxylan and increasing fermentable oligosaccharides (FOs) yield, thereby saving time in starch and protein removal. 59 Arabinoxylan may function by decreasing the quantity of sugar and cholesterol absorbed in the intestines and stomach. It may also alter the composition of the gut bacteria.…”

“…It can be used as a functional food ingredient, converted into soluble dietary fibre, 41 and yield increased fermentable sugars. 59 Extrusion-induced phytate hydrolysis in RB enhances mineral availability, including copper and zinc, potentially improving the nutritional content of food products. 62 Extrusion also boosts the soluble pentosan, soluble dietary fibre, and soluble starch content in RB.…”

“…Its richness in feruloyl arabinoxylan can yield feruloyl oligosaccharides (FOs) through enzymatic extrusion. 59 This enhances its functional properties and reduces antinutritional factors like phytates, 62 making it valuable for various food applications. Extrusion technology allows for the incorporation of RB into a wide range of foods, including meat analogues, biscuits, cookies, cakes, noodles, bread, pasta, and extrudates.…”

Effect of Extruder Configuration and Extrusion Cooking Processing Parameters on Selected Characteristics of Non-Starch Polysaccharide-Rich Wheat Flour as Hybrid Treatment with Xylanase Addition

“…High mechanical energy input might be conducive to forming a loose and porous structure that facilitates the penetration of the xylanasecontaining solution. The lower screw speed is a result of longer residence time and lower mechanical force produced from the extruder [51]. Furthermore, an increase in the screw speed leads to higher specific mechanical energy SME input, which results in depolymerization of lignocellulose and conversion of arabinoxylan chains into soluble small molecules.…”

“…This effect may create complexes with proteins and thus changes in the rheological characteristics of the wheat dough's protein-dependent functions. Therefore, it was inferred that extrusion at a higher screw speed produces more soluble pentose, even if no enzymes are added [51].…”