Variations in the appearance quality of brown rice during the four stages of milling

Effect of milling on in vitro Digestion-Induced release and bioaccessibility of active compounds in rice

To investigate the impact of milling on the active components in rice, this study examined the stability of phenols, vitamin B1 (VB1), and alpha-aminobutyric acid (α-GABA) during cooking and digestion of rice and their distribution in digestive juices and residue by adjusting the degree of milling (DOM). The findings revealed that milling exacerbated the instability of γ-GABA during cooking and VB1 during digestion. Their total losses peaked at 19.76% and 39.53% as DOM respectively reached 6.07% and 8.06%. In vitro digestion combined with release mathematical models demonstrated the impact of milling on their bioaccessibility. This effect increased the small intestinal bioaccessibility of phenols and γ-GABA, whilst reducing that of VB1. This was attributed to milling-induced pre-gastric full release of VB1, which amplifies its intestinal susceptibility and induces its re-entry into digestive residues. In conclusion, this study recommends keeping DOM below 6.07% to optimize the bioaccessibility of these active compounds.

Phytosterols in rice bran and their health benefits

With the continuous technological innovation in the high-value utilization of rice bran byproducts, rice bran oil retains a higher concentration of beneficial components such as a well-balanced composition of fatty acids and abundant phytosterols. This makes it a highly nutritious and healthy vegetable oil. This review provides an overview of the advancements made in separating, purifying, and processing phytosterols in rice bran oil. The review also introduces techniques for assessing the stability of rice bran oil. Moreover, the review emphasizes the nutritional value of phytosterols found in rice bran oil, highlighting their various health benefits, including their anticancer, anti-inflammatory, anti-allergic, antibacterial, cholesterol-lowering, skin-protective, anti-obesity, anti-diabetic, neuroprotective, gastroprotective, and immune-enhancing effects. Attaining a comprehensive understanding of the research progress made in phytosterols derived from rice bran oil can offer valuable guidance for the efficient utilization of rice bran.

Review of technology advances to assess rice quality traits and consumer perception

The increase in rice consumption and demand for high-quality rice is impacted by the growth of socioeconomic status in developing countries and consumer awareness of the health benefits of rice consumption. The latter aspects drive the need for rapid, low-cost, and reliable quality assessment methods to produce high-quality rice according to consumer preference. This is important to ensure the sustainability of the rice value chain and, therefore, accelerate the rice industry toward digital agriculture. This review article focuses on the measurements of the physicochemical and sensory quality of rice, including new and emerging technology advances, particularly in the development of low-cost, non-destructive, and rapid digital sensing techniques to assess rice quality traits and consumer perceptions. In addition, the prospects for potential applications of emerging technologies (i.e., sensors, computer vision, machine learning, and artificial intelligence) to assess rice quality and consumer preferences are discussed. The integration of these technologies shows promising potential in the forthcoming to be adopted by the rice industry to assess rice quality traits and consumer preferences at a lower cost, shorter time, and more objectively compared to the traditional approaches.

Effect of Layered Debranning Processing on the Proximate Composition, Polyphenol Content, and Antioxidant Activity of Whole Grain Wheat

Layered debranning processing (LDP) of whole grain wheat (WGW) could not only retain more bioactive compounds but also contributes to grain saving policy as compared with the refined wheat flour (WF). In this study, effect of different debranning rates from 0 to 13.37% on the proximate composition, polyphenol content, and the antioxidant activity were analyzed. As debranning rates increased from 0 to 13.37%, the insoluble dietary fiber content decreased from 9.94% to 6.47%, whereas the soluble dietary fiber contents increased from 3.06% to 3.98%. The free phenolic content decreased by 62.72%, while the free flavonoid content increased by 4.68% with debranning rates increasing. For the phenolic acids, protocatechuic acid and ferulic acid dominated the free and bound phenolic acid in WGW, which showed the highest contents at 6.95% and 4.45% debranning rates, respectively. As for flavonoids, naringenin (the free-state phenolic) and rutin (the bound state phenolic) in WGW had the greatest level at 4.45% debranning rate. As compared to WGW and WF, LDP significantly improved the DPPH, ABTS·+ radical scavenging activities and total antioxidant activities. In conclusion, 4.45% and 6.95% were the best debranning rates to retain polyphenol contents and antioxidant activities.

INFLUENCE OF OPERATING PARAMETERS ON THE MILLING QUALITY OF LONG-GRAIN WHITE RICE

The current study aimed to test and evaluate sheets’ different perforation shapes, brake angles, and milling durations to improve the quality of long-grain white rice from an abrasive milling machine. The investigated parameters of head rice yield, broken rice percentage, whitening degree, and rice bulk temperature were influenced by five sheets with five perforated shapes (horizontal, vertical, inclined, 1 mm round holes, and 1.5 mm round holes), three brake angles (0, 45, and 90º), and four milling durations (60, 70, 80, and 90 s). The results showed that the horizontal rectangular perforated sheet resulted in the highest value of head rice yield and the lowest value of broken rice. On the other hand, the vertical rectangular perforated sheet resulted in the highest whitening degree, followed by the inclined rectangular perforated sheet. The round holes (1.0 mm and 1.5 mm diameter) are not recommended for the long-grain whitening process because of the resulting high values of broken kernels, rice bulk temperature after the whitening process, and lower values of whitening degree. The brake angle of 90º resulted in the highest value of broken rice for all studied perforated sheets used in this study. This study recommended that the optimum operating conditions were using the horizontal rectangular perforated sheet, zero degree brake angle and milling duration of 80 s.