Optimization of Extrusion Treatments, Quality Assessments, and Kinetics Degradation of Enzyme Activities during Storage of Rice Bran

Abstract

Over the years, extrusion has been a multi-step thermal technique that has proven to be the most effective process to stabilize rice bran (RB). This study aimed to investigate the effects of extrusion treatment and temperature (15, 25, and 40 °C) on the storage stability, lipid oxidation, peroxidase, and peroxide values, free fatty acids, fatty acid composition, and protein variations of RB over 60 days. The study offers novel insights into the changes in RB’s protein and amino acid compositions during extrusion and storage, which has not been extensively explored in prior research. After extrusion processing, peroxidase activity (POD) and lipase activity (LPS) were significantly reduced. However, peroxide value (PV), free fatty acids (FFA), and malondialdehyde content (MDA) observed a significantly increased by 0.64 mEqO2/kg, 8.3 mg/100 g, and 0.0005 μmol/L respectively. The storage stability of RB after extrusion shows that the POD, LPS, FFA, PV, and MDA were positively correlated with storage duration and temperature. The oleic acid/linoleic acid ratio in processed RB by extrusion had no significant changes during storage. The total and essential/non-essential amino acid ratios showed a downward trend of 5.26% and 8.76%, respectively. The first-order kinetics was the best-fitting model to describe the enzymatic inactivation and degradation of extruded RB during storage. The extrusion treatment did not affect the crude protein and the essential subunits of protein. Overall, the optimized extrusion procedure exhibited promising results in stabilizing the RB.

Determining the effect of raw materials moisture and lipid content on the technological properties of the extruded protein-fat system

“…The development differs from the results of the study [11], where a rational ratio of the basic components of extruded animal feed was determined without varying the moisture and lipid content. Also, the development differs from the works [27,28], where the influence of the moisture and fat content of the raw material on the technological parameters of extruded products was investigated, because protein-containing by-products of the oil-producing industry in combination with grain raw materials were chosen as raw components. The extruded protein-fat system of the developed composition has a high crude protein content (Table 2), as well as high porosity due to the rational ratio of moisture and lipids in the raw material (Fig.…”

“…Using the example of rice bran, the authors of the work [28] found that the content of proteins, lipids and moisture of the raw material affects the process of extrusion of the raw material. In particular, an increase in moisture content contributes to an increase in the yield strength of the extrudate, its better formation and, accordingly, a more even distribution of pressure inside the extruder.…”

Oxidative Stability and Pasting Properties of High-Moisture Japonica Brown Rice following Different Storage Temperatures and Its Cooked Brown Rice Flavor

“…Figure 1B,C shows that the carbonyl value and the malondialdehyde content of brown rice with high moisture content samples increased with storage time, indicating that the cell membrane integrity was gradually compromised, and the quality deteriorated. Specifically, the carbonyl values and the malondialdehyde content of brown rice samples at 15 • C storage for 90 days were significantly lower than those stored at 20 • C and 25 • C. Similarly, Liu et al [14] discovered that the carbonyl values of brown rice stored at 15 • C for 270 days were significantly lower than those at 25 • C and 35 • C. Additionally, Muhammad et al [26] found that the elevated temperature led to increased oxidation and malondialdehyde levels in rice bran over the course of storage. Consequently, it could be inferred that japonica brown rice with high moisture content at a temperature of 15 • C storage retarded the growth of its peroxide value, carbonyl value, and malondialdehyde content, which were beneficial to retaining its freshness.…”

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

“…Protein can be denatured in extrusion due to high temperature and shear force, but many studies suggest no significant effect on the protein content of RB. 61…”