Effect of particle size of rice bran on gamma-oryzanol content and compounds

Efficacy of rice bran extract for alleviating depressive symptoms in adults: A randomized, double-blind, placebo-controlled trial

BACKGROUND

Preclinical research indicates the potential benefit of rice bran extract supplements (RBS) in improving depressive-like behaviors and symptoms.

OBJECTIVE

We aimed to evaluate the efficacy and safety of an 8-week administration of RBS in alleviating depressive symptoms among adults with mild-to-moderate symptom severity.

METHODS

This randomized, double-blind, placebo-controlled trial included 100 adults (aged 19-75 years) with scores of 7-24 on the Korean version of the Hamilton Depression Rating Scale (K-HDRS). Participants were randomly assigned to receive 1 g/day of RBS or a placebo for 8 weeks. Evaluations at baseline and after 8 weeks included mood assessments using K-HDRS, the Korean version of the Beck Depression Inventory-II (K-BDI-II), the Patient Health Questionnaire-9 (K-PHQ-9), the Beck Anxiety Inventory (K-BAI), and other psychological scales. Biomarker measurements included serum brain-derived neurotrophic factor, serotonin, dopamine, and salivary cortisol.

RESULTS

In the RBS and placebo groups, 47 and 50 participants, respectively, completed the intervention. At 8 weeks, the RBS group exhibited greater reductions in K-HDRS scores compared to the placebo group (P<0.001), with adjusted differences of -5.73 (95% confidence interval [CI]: -7.07, -4.39; intention-to treat analysis [ITT]) and -5.95 (95% CI: -7.33, -4.57, per-protocol analysis [PP]), corresponding to percent changes of -45.1% (ITT) and -46.0% (PP), respectively. A trend toward greater reductions in the percent changes of K-BDI-II and K-BAI scores was observed in the RBS group compared to the placebo group (ITT and PP). Notably, K-PHQ-9 scores were lower in the RBS group than in the placebo group (P=0.026, PP) after 8 weeks of treatment. However, no significant intergroup differences were identified in other questionnaire scores or biomarker measurements. No adverse events were reported.

CONCLUSION

RBS may provide a beneficial effect on depressive symptoms of mild-to-moderate severity in adults. This trial was registered at clinicaltrials.gov as NCT05180136. https://clinicaltrials.gov/study/NCT05180136.

Cell-free and cell-based antidiabetic effects and chemical characterization of rice bran from Thai cultivars

Rice bran is a valuable by-product of rice milling, prized for its nutritional value and health benefits. This study investigates the antidiabetic properties of rice bran from fifteen commercially available Thai rice cultivars (six brown, four red and five purple). Bran samples were initially screened on their antioxidant potential and ability to inhibit α-glucosidase, as well as on γ-oryzanol levels, total phenolic and total flavonoid contents. Top-ranked cultivars were thoroughly investigated for their antidiabetic potential, samples from red and purple cultivars exhibiting greater activity. Samples from the red cultivar Hom Mali Dang (HMD) demonstrated higher potential to inhibit the activity of α-amylase and aldose reductase (IC50 values of 413.19 ± 57.04 and 205.42 ± 26.47 µg/mL, respectively), along with potent α-glucosidase inhibition in Caco-2 cells (IC50 = 158 µg/mL). Our study highlights the potential of underexplored Thai rice bran cultivars, particularly HMD, as a promising ingredient for diabetic-friendly food supplements.

Rice Bran Stabilisation and Oil Extraction Using the Microwave-Assisted Method and Its Effects on GABA and Gamma-Oryzanol Compounds

Rice bran oil (RBO) is a valuable ingredient extracted from rice bran (RB), a side stream of polishing rice grain in the milling process. RBO is rich in bioactive ingredients with potential health benefits, such as gamma-oryzanol (GO) and gamma-aminobutyric acid (GABA). Despite its benefits, the quality of RBO depends on the degree of stabilisation of the RB, which is easily affected by lipase enzymes, and thus needs an effective treatment prior to RBO production. To assess the potential of the microwave-assisted method for RB stabilisation and RBO extraction, three Carolino rice varieties (Ariete, Teti, Luna) were tested. The effect of RB stabilisation was evaluated via acid value, water absorption, and GO and GABA levels. The RBO yield was optimised by solvent, temperature, and solvent-to-sample ratio, and the GO and fatty acid levels were determined. The RB stabilisation for the Luna variety did not affect the GO and GABA; for the Ariete and Teti varieties, the GO decreased by 34.4% and 24.2%, and the GABA increased by 26.5% and 47.0%, respectively. The GO levels in RBO samples were not affected by RB stabilisation. The RBO nutritional value was confirmed by the suitable ratio (>2) between polyunsaturated (PUFA) and saturated fatty acids (SFA), with the Teti variety presenting the highest ratio.

Production of a rich-carotenoid colorant from pumpkin peels using oil-in-water emulsion followed by spray drying

Peels and seeds are byproducts generated during the processing of fruits and vegetables that have been cut off or rejected in the food industry. Pumpkin peels are an example of products that provide valuable nutritional aspects but that have low commercial value. This work aimed at recovering carotenoids from pumpkin peels to produce valuable powders. The pumpkin peel flour was obtained from convective drying and milling processes. Liquid-solid extraction produced the ethanol raw extract with a high carotenoid content. Carotenoid extract and Arabic gum suspensions were mixed in proportions of 1:2, 1:3, or 1:4 w/w. Emulsions produced via Ultra-Turrax (UT) and Ultra-Turrax plus high pressure (UTHP) were evaluated and spray dried. The particles carotenoid concentrations varied from 159.1 to 304.6 µg/g and from 104.3 to 346.2 µg/g for samples primarily produced via UT and UTHP, respectively. UTHP 1:3 particles showed the lowest degradation of carotenoids during 90 days of storage, with a retention index of 79%. The homogenization and spray drying techniques were proven to be suitable steps to preserve the carotenoids recovered from the byproduct studied. Microparticles can be used as a natural dye with potential use in food, pharmaceuticals, and cosmetics.

Rice Compounds with Impact on Diabetes Control

Rice is one of the most cultivated and consumed cereals worldwide. It is composed of starch, which is an important source of diet energy, hypoallergenic proteins, and other bioactive compounds with known nutritional functionalities. Noteworthy is that the rice bran (outer layer of rice grains), a side-stream product of the rice milling process, has a higher content of bioactive compounds than white rice (polished rice grains). Bran functional ingredients such as γ-oryzanol, phytic acid, ferulic acid, γ-aminobutyric acid, tocopherols, and tocotrienols (vitamin E) have been linked to several health benefits. In this study, we reviewed the effects of rice glycemic index, macronutrients, and bioactive compounds on the pathological mechanisms associated with diabetes, identifying the rice compounds potentially exerting protective activities towards disease control. The effects of starch, proteins, and bran bioactive compounds for diabetic control were reviewed and provide important insights about the nutritional quality of rice-based foods.

Supercritical Carbon Dioxide Extraction, Antioxidant Activity, and Fatty Acid Composition of Bran Oil from Rice Varieties Cultivated in Portugal

Bran of different rice cultivars produced in Portugal were used to study supercritical carbon dioxide extraction conditions of rice bran oil (RBO) and evaluate and compare antioxidant activity and fatty acid composition of the different rice bran varieties. The effect of plant loading (10–20 g), CO2 flow rate (0.5–1.5 L/min), pressure (20–60 MPa), and temperature (40–80 °C) was studied. The amount of oil extracted ranged from 11.72%, for Ariete cultivar, to 15.60%, for Sirio cultivar. The main fatty acids components obtained were palmitic (13.37%–16.32%), oleic (44.60%–52.56%), and linoleic (29.90%–38.51%). Excellent parameters of the susceptibility to oxidation of the oils were obtained and compare. RBO of Ariete and Gladio varieties presented superior DPPH and ABTS radical scavenging activities, whereas, Minima, Ellebi, and Sirio varieties had the lowest scavenging activities. Moreover, the oil obtained towards the final stages of extraction presented increased antioxidant activity.

Exploiting the bioactive properties of γ-oryzanol from bran of different exotic rice varieties

The rice industry is one of the most significant food industries since rice is a widely consumed cereal in the world. As a result of this substantial production, the rice industry has a significant amount of side streams, including bran, representing millions of tons of raw materials mainly designated to animal feed. Rice bran is a rich source of γ-oryzanol, a bioactive compound with substantial health benefits. In this perspective, different bran rice samples from distinct germplasm origins (Philippines, Italy and Portugal) were studied for their γ-oryzanol content by HPLC-PDA, cytotoxicity in four human tumour cell lines, hepatotoxicity in a normal cell line and for their antimicrobial effects on different bacterial and fungal strains. The Ballatinao sample presented the strongest activity against all the tumour cell lines, and was also the sample showing the highest amount of γ-oryzanol, suggesting its contribution to the exhibited cytotoxic properties. Regarding the antimicrobial activity, the tested samples were able to inhibit the majority of bacterial and fungal strains, with the Portuguese Ceres sample being the one presenting the highest bacterial inhibition and the Maluit and Dinorado samples, the highest fungal inhibition. Overall, the results show that rice bran extracts may be considered as potential candidates for antimicrobial agents when incorporated into food matrices.

Nutritional Value and Modelling of Carotenoids Extraction from Pumpkin (Cucurbita Moschata) Peel Flour By-Product

By-products from fruits and vegetables are slices and peels that have been removed or rejected by the food industry and are considered to have low commercial value. Pumpkin peel is a source of carotenoids, minerals, antioxidants and phenolic compounds. This work studied the nutritional value of pumpkin peel flours produced by convective drying (40 °C) and milling. Pumpkin peel flours contained high contents of insoluble fibres (24.46 g/100 g), potassium (19.1 g/kg) and iron (152.5 mg/kg). Carotenoids were extracted using hexane at 40 °C, and flour particles were classified by 35-, 80- and 100-mesh sieves. The total carotenoids content ranged from 216.9 to 306.8 μg/g. Fick’s second law model computed that 215 min was required to extract 99 % of the total carotenoids. This work evidenced the effects of particle size on carotenoids extraction efficiency and demonstrated that pumpkin by-product flour could be used as a food ingredient or natural dye.