Impact of Enzymatic Hydrolysis and Microfluidization on the Techno-Functionality of Oat Bran in Suspension and Acid Milk Gel Models

Abstract

Oat bran is a nutritionally rich ingredient, but it is underutilized in semi-moist and liquid foods due to technological issues such as high viscosity and sliminess. The aim of this work was to improve the technological properties of oat bran concentrate (OBC) in high-moisture food applications by enzymatic and mechanical treatments. OBC was hydrolyzed with β-glucanase (OBC-Hyd) and the water-soluble fraction (OBC-Sol) was separated. OBC, OBC-Hyd and OBC-Sol were further microfluidized at 5% dry matter content. Enzymatic treatment and microfluidization of OBC reduced the molecular weight (Mw) of β-glucan from 2748 kDa to 893 and 350 kDa, respectively, as well as the average particle size of OBC (3.4 and 35 times, respectively). Both treatments increased the extractability of the soluble compounds from the OBC samples (up to 80%) and affected their water retention capacity. OBC in suspension had very high viscosity (969 mPa·s) when heated, which decreased after both enzyme and microfluidization treatments. The colloidal stability of the OBC in suspension was improved, especially after microfluidization. The addition of OBC samples to acid milk gels decreased syneresis, improved the water holding capacity and softened the texture. The changes in the suspension and gel characteristics were linked with reduced β-glucan Mw and OBC particle size.

Perspectives in the Application of High, Medium, and Low Molecular Weight Oat β-d-Glucans in Dietary Nutrition and Food Technology—A Short Overview

“…After extraction, the physical properties and M w of isolated β - d -glucan undergo modifications by various treatments [ 50 ]. For example, the enzymatic treatment and micro-fluidization of oat β - d -glucan reduces both M w and the average size of particles, increases extractability up to 80%, water retention capacity, decreases the viscosity of the β - d -glucan suspension, and increases colloidal stability [ 95 ]. Roubroeks et al [ 88 ] used cellulase (EC 3.2.1.4) from Trichoderma sp to partially depolymerize oat β - d -glucan.…”

Oat milk analogue versus traditional milk: Comprehensive evaluation of scientific evidence for processing techniques and health effects

“…After α-amylase–alkali treatment of oat milk, Babolanimogadam et al (2023) discovered that compared with the untreated group, oat milk yield, and protein extraction increased significantly, especially the protein extraction rate, which was approximately 80% and 60%, respectively, and the protein concentration was significantly higher than that of other treatments ( Babolanimogadam et al, 2023 ). Similarly, β-glucan, a dietary fiber rich in oats that exhibits an effect on the sensory properties of oat milk to some extent, increases the viscosity of oat milk, and β-glucan with high molecular weight (Mw) tends to form a semisolid ( Lyly et al, 2003 , Rosa-Sibakov et al, 2022 ). Therefore, it is necessary to depolymerize β-glucan by enzymes to generate a suspension of β-glucan with low viscosity and high concentration ( Sibakov et al, 2013 ).…”

“…It was found that more phenolic compounds were detected in urine after β-glucan was ingested with a low Mw (82 kDa) compared to a high Mw (1000 kDa) and a medium Mw (524 kDa) ( Hakkola et al, 2020 ). It has been demonstrated that the Mw of β-glucan could be significantly reduced from 2748 kDa to 893 kDa and 350 kDa with the treatment of oat bran concentrates with β-glucanase, reducing the concentration of concentrate and improving the water holding capacity ( Rosa-Sibakov et al, 2022 ). Therefore, the selection and technology of enzymes affect the taste, flavor, and nutritional properties of oat milk.…”

Assessment of the Quality Attributes of Oat β-glucan Fortified Reduced-Fat Goat Milk Yogurt Supported by Microfluidization

“…According to the American Food and Drug Administration (FDA), the positive effects of β-glucan on health can occur when 0.75 g is consumed per serving [ 21 ] and the daily intake of β-glucan recommended by the FDA is 3 g [ 19 , 22 ]. Technologically, β-glucans are also functional depending on their molecular weight (Mw), source of origin, extraction method, and degree of purification [ 23 , 24 ]. Oats are the most important known sources of natural β-glucan; with a content of 3–7% [ 19 , 25 , 26 ].…”