Improvement of germinated brown rice quality with autoclaving treatment

Autoclaving-treated germinated brown rice relieves hyperlipidemia by modulating gut microbiota in humans

Introduction

Germinated brown rice is a functional food with a promising potential for alleviating metabolic diseases. This study aimed to explore the hypolipidemic effects of autoclaving-treated germinated brown rice (AGBR) and the underlying mechanisms involving gut microbiota.

Methods

Dietary intervention with AGBR or polished rice (PR) was implemented in patients with hyperlipidemia for 3 months, and blood lipids were analyzed. Nutritional characteristics of AGBR and PR were measured and compared. Additionally, 16S rDNA sequencing was performed to reveal the differences in gut microbiota between the AGBR and PR groups.

Results

AGBR relieves hyperlipidemia in patients, as evidenced by reduced levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein-B, and elevated levels of high-density lipoprotein cholesterol and apolipoprotein-A1. In terms of nutrition, AGBR had significantly higher concentrations of free amino acids (10/16 species), γ-aminobutyric acid, resistant starch, soluble dietary fiber, and flavonoids (11/13 species) than PR. In addition, higher microbial abundance, diversity, and uniformity were observed in the AGBR group than in the PR group. At the phylum level, AGBR reduced Firmicutes, Proteobacteria, Desulfobacterota, and Synergistota, and elevated Bacteroidota and Verrucomicrobiota. At the genus level, AGBR elevated Bacteroides, Faecalibacterium, Dialister, Prevotella, and Bifidobacterium, and reduced Escherichia-Shigella, Blautia, Romboutsia, and Turicibacter.

Discussion

AGBR contributes to the remission of hyperlipidemia by modulating the gut microbiota.

Effects of whole grains on glycemic control: a systematic review and dose-response meta-analysis of prospective cohort studies and randomized controlled trials

PURPOSE

Whole grains have recently been promoted as beneficial to diabetes prevention. However, the evidence for the glycemic benefits of whole grains seems to conflict between the cohort studies and randomized control trials (RCTs). To fill the research gap, we conducted a meta-analysis to determine the effects of whole grains on diabetes prevention and to inform recommendations.

METHODS

We searched PubMed, Clarivate Web of Science, and Cochrane Library until March 2024. We used the risk ratio (RR) of type 2 diabetes to represent the clinical outcomes for cohort studies, while the biomarkers, including fasting blood glucose and insulin, HbA1C, and HOMA-IR, were utilized to show outcomes for RCTs. Dose-response relationships between whole grain intakes and outcomes were tested with random effects meta-regression models and restricted cubic splines models. This study is registered with PROSPERO, CRD42021281639.

RESULTS

Ten prospective cohort studies and 37 RCTs were included. Cohort studies suggested a 50 g/day whole grain intake reduced the risk of type 2 diabetes (RR = 0.761, 95% CI: 0.700 to 0.828, I2 = 72.39%, P < 0.001) and indicated a monotonic inverse relationship between whole grains and type 2 diabetes rate. In RCTs, whole grains significantly reduced fasting blood glucose (Mean difference (MD) = -0.103 mmol/L, 95% CI: -0.178 to -0.028; I2 = 72.99%, P < 0.01) and had modest effects on HbA1C (MD = -0.662 mmol/mol (-0.06%), 95% CI: -1.335 to 0.010; I2 = 64.55%, P = 0.05) and HOMA-IR (MD = -0.164, 95% CI: -0.342 to 0.013; I2 = 33.38%, P = 0.07). The intake of whole grains and FBG, HbA1C, and HOMA-IR were significantly dose-dependent. The restricted spline curves remained flat up to 150 g/day and decreased afterward. Subgroup analysis showed that interventions with multiple whole-grain types were more effective than those with a single type.

CONCLUSION

Our study findings suggest that a daily intake of more than 150 g of whole grain ingredients is recommended as a population approach for diabetes prevention.

Whole grain germinated brown rice intake modulates the gut microbiota and alleviates hypertriglyceridemia and hypercholesterolemia in high fat diet-fed mice

Hyperlipidemia is a common clinical disorder of lipid metabolism in modern society and is considered to be one of the major risk factors leading to cardiovascular-related diseases. Germinated brown rice (GBR) is a typical whole grain food. The lipid-lowering effect of GBR has received increasing attention, but its mechanism of action is not fully understood. The gut microbiota has been proposed as a novel target for the treatment of hyperlipidemia. The aim of this study was to investigate the effects of GBR on the gut microbiota and lipid metabolism in high-fat diet (HFD)-fed C57BL/6J mice. The effect of GBR on hyperlipidemia was evaluated by measuring blood lipid levels and by pathological examination. The gut microbiota was detected by 16S rRNA sequencing, and the protein and mRNA expression levels involved in cholesterol metabolism were detected by western blotting and RT-qPCR to find potential correlations. The results showed that GBR supplementation could effectively reduce the levels of TC, TG, LDL-C and HDL-C in the serum and alleviate the excessive accumulation of fat droplets caused by HFD. Moreover, GBR intervention improved HFD-fed gut microbiota disorder via increasing the diversity of the gut microbiota, reducing the Firmicutes/Bacteroidetes ratio, and improving gut barrier damage. In addition, GBR could inhibit endogenous cholesterol synthesis and promote cholesterol transport and excretion. These findings suggest that GBR may be a competitive candidate for the development of functional foods to prevent abnormal lipid metabolism.

Health-promoting germinated rice and value-added foods: a comprehensive and systematic review of germination effects on brown rice

Over the last 30 years, thousands of articles have appeared examining the effects of soaking and germinating brown rice (BR). Variable germination conditions and methods have been employed to measure different health-beneficial parameters in a diverse germplasm of BR. Research results may therefore appear inconsistent with occasional anomalies, and it may be difficult to reach consensus concerning expected trends. Herein, we amassed a comprehensive review on germinated brown rice (GBR), attempting to codify 133 peer-reviewed articles regarding the effects on 164 chemical parameters related to health and nutrition in BR and in value-added food products. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA-2020) approach was used to direct the flow of the literature search. A pair-wise comparison t-test was performed to deliver an overall approach indicating when a given compound has been found to significantly increase or decrease through germination, which was grouped into GABA and polyamines, γ-Oryzanol and phytosterols, phenolic compounds, vitamins, proteins and amino acids, starchy carbohydrates, free sugars, lipids, minerals and phytic acid. This resource will stimulate interest in germinating rice and optimistically help increase both production and consumption of highly nutritious, health-beneficial rice with pigmented bran.

Evaluation of Precision and Sensitivity of Back Extrusion Test for Measuring Textural Qualities of Cooked Germinated Brown Rice in Production Process

The textural qualities of cooked rice may be understood as a dominant property and indicator of eating quality. In this study, we evaluated the precision and sensitivity of a back extrusion (BE) test for the texture of cooked germinated brown rice (GBR) in a production process. BE testing of the textural properties of cooked GBR rice showed a high precision of measurement in hardness, toughness and stickiness tests which indicated by the repeatability and reproductivity test but the sensitivity indicated by coefficient of variation of the texture properties. The findings of our study of the effects on cooked GBR texture of different soaking and incubation durations in the production of Khao Dawk Mali 105 (KDML 105) GBR, as measured by BE testing, confirmed that our original protocol for evaluation of the precision and sensitivity of this texture measurement method. The coefficients of determination (R2) of hardness, toughness and stickiness tests and the incubation time at after 48 hours of soaking were 0.82, 0.81 and 0.64, respectively. The repeatability and reproducibility of reliable measurements, which have a low standard deviation of the greatest difference between replicates, are considered to indicate high precision. A high coefficient of variation where relatively wide variations in the absolute value of the property can be detected indicates high sensitivity when small resolutions can be detected, and vice versa. The sensitivity of the BE tests for stickiness, toughness and hardness all ranked higher, in that order, than the sensitivity of the method for adhesiveness, which ranked lowest. The coefficients of variation of these texture parameters were 31.26, 20.59, 19.41 and 18.72, respectively. However, the correlation coefficients among the texture properties obtained by BE testing were not related to the precision or sensitivity of the test. By obtaining these results, we verified that our original protocol for the determination of the precision and sensitivity of food texture measurements which was successfully used for GBR texture measurement.

Precooking treatments affect the sensory and tensile properties of autoclaved recooked noodles via moisture distribution and protein structure

To improve the quality of autoclaved recooked noodles (ARNs), this study explored the effects of precooking on the sensory and tensile properties of ARNs from the perspectives of changes in protein structure and water distribution. The results showed that the ARNs of two kinds of pretreatments (Boiling 2 min, Boiling 1 min + Steaming 2 min) presented the best sensory quality (average score ≥ 7.50) and high tensile properties (tensile distance ≥ 45.24 mm). After autoclaving and recooking, the proportion of tightly bound water increased by 11.30%-12.52%, resulting in stronger water-solid interaction. The results of laser confocal microscopy (CLSM) proved that a strengthened gluten network (protein percentage area ≥ 40.28%; junction density ≥ 10.96 × 10^-4) appeared. Therefore, appropriate precooking treatment could effectively improve the sensory quality and tensile properties of ARNs by enhancing the tightly bound water ratio and strengthening the gluten network.

White rice, brown rice and the risk of type 2 diabetes: a systematic review and meta-analysis

OBJECTIVE

Intake of white rice has been associated with elevated risk for type 2 diabetes (T2D), while studies on brown rice are conflicting. To inform dietary guidance, we synthesised the evidence on white rice and brown rice with T2D risk.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, EMBASE and Cochrane databases were searched through November 2021.

ELIGIBILITY CRITERIA

Prospective cohort studies of white and brown rice intake on T2D risk (≥1 year), and randomised controlled trials (RCTs) comparing brown rice with white rice on cardiometabolic risk factors (≥2 weeks).

DATA EXTRACTION AND SYNTHESIS

Data were extracted by the primary reviewer and two additional reviewers. Meta-analyses were conducted using random-effects models and reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias was assessed using the Newcastle Ottawa Scale for prospective cohort studies and the Cochrane Risk of Bias Tool for RCTs. Strength of the meta-evidence was assessed using NutriGrade.

RESULTS

Nineteen articles were included: 8 cohort studies providing 18 estimates (white rice: 15 estimates, 25 956 cases, n=5 77 426; brown rice: 3 estimates, 10 507 cases, n=1 97 228) and 11 RCTs (n=1034). In cohort studies, white rice was associated with higher risk of T2D (pooled RR, 1.16; 95% CI: 1.02 to 1.32) comparing extreme categories. At intakes above ~300 g/day, a dose-response was observed (each 158 g/day serving was associated with 13% (11%-15%) higher risk of T2D). Intake of brown rice was associated with lower risk of T2D (pooled RR, 0.89; 95% CI: 0.81 to 0.97) comparing extreme categories. Each 50 g/day serving of brown rice was associated with 13% (6%-20%) lower risk of T2D. Cohort studies were considered to be of good or fair quality. RCTs showed an increase in high-density lipoprotein-cholesterol (0.06 mmol/L; 0.00 to 0.11 mmol/L) in the brown compared with white rice group. No other significant differences in risk factors were observed. The majority of RCTs were found to have some concern for risk of bias. Overall strength of the meta-evidence was moderate for cohort studies and moderate and low for RCTs.

CONCLUSION

Intake of white rice was associated with higher risk of T2D, while intake of brown rice was associated with lower risk. Findings from substitution trials on cardiometabolic risk factors were inconsistent.

PROSPERO REGISTRATION NUMBER

CRD42020158466.

Black mahlab (Monechma ciliatum L.) seeds: processing effects on chemical composition and nutritional value

Introduction. Monechma ciliatum L. seeds are rich in proteins, carbohydrates, oils and mineral contents. Researchers have focused on new production development but there is no available data on the impact of processing techniques on the quality of the seeds. Our study aimed to investigate the impact of boiling, roasting, and germination on the composition and nutritional value of Monechma ciliatum (black mahlab) seeds. Study objects and methods. We analyzed 7 kg of black mahlab seeds purchased from the local market. We applied standard methods used in boiling, roasting, and germination techniques. Proximate analyses were performed using the methods of the Association of Official Analytical Chemists. Minerals were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS), and fatty acids were determined by gas chromatography. Tocopherols and amino acids in processed seeds were determined by high-performance liquid chromatography. Results and discussion. The results showed that the proximate compositions of untreated, boiled, roasted, and germinated mahlab seeds were affected by boiling, roasting, and germination techniques. Most of the nutritional values were enhanced by all the treatments. In particular, all the processing techniques increased the protein content. Boiling and roasting increased the fat content, while boiling and germination increased the fiber content. Tocopherols were higher only in the germinated samples. Amino acids were increased by all the techniques. Minerals were affected by all the techniques, except for Na, which was higher in the germinated sample. Conclusion. Boiling, roasting, and germination enhanced significantly the chemical composition of Monechma ciliatum seeds, which make them a value ingredient to develop new food products.

Optimization of γ-Aminobutyric Acid (GABA) Accumulation in Germinating Adzuki Beans (Vigna angularis) by Vacuum Treatment and Monosodium Glutamate, and the Molecular Mechanisms

This study aimed to investigate the optimal hypoxic and monosodium glutamate (MSG) stress conditions for the enrichment of γ-Aminobutyric acid (GABA) in germinating adzuki beans and to reveal the potential underlying molecular mechanisms of GABA accumulation. Using single-factor experiments and response surface model, we investigated the effects of germination time, germination temperature, vacuum time, and MSG concentration on GABA contents, and further explored the activity and gene expression of glutamate decarboxylase (GAD) and polyamine oxidase (PAO) critical rate restriction enzymes during GABA synthesis. The optimal soaking temperature, soaking time, and pH conditions were 35°C, 16 h, and 5, respectively. Furthermore, the optimal germination conditions for optimal GABA enrichment were 48 h, 1.99 mg/ml MSG concentration, germination temperature of 31.49°C, and vacuum time of 15.83 h. Under such conditions, the predicted GABA concentration was 443.57 ± 7.18 mg/100 g, with no significant difference between the predicted and experimental data. The vacuum + MSG (FZM) treatment has a maximum contribution rate of GABA to 38.29%, which significantly increase GABA content, and the increase was associated with increased GAD and PAO activity. In addition, MSG in combination with vacuum treatment could significantly induce VaGAD4 and VaGAD6 genes in 2 days germination of adzuki beans. According to the results of the present study, vacuum + MSG treatment is an effective approach to enhancing GABA accumulation in germinating adzuki beans, which could be employed in enhancing the functional quality of germinating adzuki beans.

Increased γ-Aminobutyric Acid Content of Germinated Brown Rice Produced in Membrane Reactor

RESEARCH BACKGROUND

Rice germination is a natural approach to enhance the physical and functional properties of brown rice. Thus, the aim of this study is to investigate the influence of different germination methods on functional properties of germinated brown rice and evaluate the process feasibility.

EXPERIMENTAL APPROACH

Brown rice of IPB 3S variety was germinated with three different methods: (i) complete soaking without water replacement, (ii) complete soaking with water replacement every six hours, and (iii) complete soaking with continuous washing in the developed membrane-facilitated soaking reactor.

RESULTS AND CONCLUSIONS

The application of the membrane reactor for producing germinated brown rice maintained the pH of the soaking solution relatively constant (i.e. 6.8-7.0). This indicated the circumvention of natural fermentation during brown rice germination. Moreover, the mass fraction of γ-aminobutyric acid in germinated brown rice produced in the membrane reactor was about 4.5-fold higher (169.2 mg/100 mg) than in ungerminated brown rice (36.82 mg/100 mg), and also higher than that of the other two soaking methods. The γ-oryzanol mass fractions and the antioxidant capacity expressed as ascorbic acid equivalents of germinated brown rice obtained with the three soaking methods varied from 32 to 38 mg/100 mg and 18 to 28 mg/100 g, respectively. Within this study, germination could also slightly reduce the transition temperatures of germinated brown rice starch gelatinization (t o=73-74 °C, t p=76-77 °C and t c=~80 °C, where t o, t p and t c are onset, peak and conclusion (final) temperatures). In conclusion, the production of germinated brown rice in the membrane reactor could enhance its γ-aminobutyric acid mass fraction and reduce wastewater production and is therefore considered more feasible.

NOVELTY AND SCIENTIFIC CONTRIBUTION

This study demonstrates the feasibility of germinated brown rice production using a membrane-facilitated soaking reactor with enhancement of bioactive compound content, especially γ-aminobutyric acid, and minimised wastewater production.

The effect of brown rice compared to white rice on adiposity indices, lipid profile, and glycemic markers: a systematic review and meta-analysis of randomized controlled trials

A few randomized controlled trials (RCTs) have assessed the effect of brown rice consumption on metabolic parameters compared to white rice, with inconsistent findings. Therefore, the present systematic review and meta-analysis was designed to evaluate the effect of brown rice on adiposity indices, lipid profile, and glycemic markers in adult subjects compared to white rice. In this study, PubMed/Medline, Scopus, Web of Sciences, and Embase databases were comprehensively searched until March 2021. Thirteen RCTs were selected and then included in the meta-analysis. As reported, brown rice significantly reduced weight by -1.63 kg (95% CI: -2.15 to -1.11, I²=97%, n = 6), body mass index (BMI) by -0.58 kg/m² (95% CI: -0.78 to -0.37, I²=96%, n = 6), and waist circumference by -2.56 cm (95% CI: -4.86 to -0.26, I²=88%, n = 5) compared with white rice. Moreover, it had no significant effect on lipid profile and glycemic markers. Besides, pre-germinated brown rice significantly declined weight (-1.75 kg, 95% CI: -2.70 to -0.81, I²=99%, n = 4), total cholesterol (-24.22 mg/dl, 95% CI: -33.03 to -15.41, I²=78%, n = 5), triglyceride (TG) (-43.28 mg/dl, 95% CI: -74.05 to -12.50, I²=90%, n = 5), low-density lipoprotein (LDL) (-20.05 mg/dl, 95% CI: -29.57 to -10.52, I²=71%, n = 5), and fasting blood glucose (FBG) (-15.83 mg/dl, 95% CI: -25.20 to -6.46, I²=91%, n = 5). In accordance with Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, the certainly of the included evidence was low and very low. The results of the present study indicate that, brown rice has anti-obesity effects in comparison with white rice; however, it has no beneficial effects on lipid profile and glycemic markers. Contrary to brown rice, it was shown that, pre-germinated brown rice significantly decreases body weight and improves lipid profile and FBG levels compared to white rice. Accordingly, our results indicate that, pre-germinated brown rice has better functional effects on promoting lipid profile and FBG compared to brown rice.

Influence of germinated brown rice-based flour modified by MAse on type 2 diabetic mice and HepG2 cell cytotoxic capacity

This study aimed to discover whether using maltogenic amylase (MAse) to modify starch in germinated brown rice flour may enhance slow digestion starch and release more bioactive compounds (BCs) content. To achieve this aim, the starch was modified with four levels of MAse (0 U, 133 U, 266 U and 399 U MAse/g flour) for 1 hr at pH 5 and then spray-dried to make modified flour. The biochemical impacts of the products were then accessed in normal and type 2 diabetic mice for 4 weeks. The result showed that when the starch was modified by MAse 266 U/g, a significant reduction of rapidly digested starch to 22.35% from 61.56%, an increase in slowly digested starch to 33.09% while resistant starch as 2.92% corresponding to the increase of γ-amino butyric acid to 528.1 ± 44.1 mg/L and 120.6 ± 10.9 mg/L of ferulic acid. The extract from modified flour showed very strong cytotoxic activity against HepG2 cell (>80% inhibition). The result in vivo showed that the type-2 diabetic mice fed with this modified product could better improve the stability of the glycemic index. Also, atherosclerotic plaque assessment further supports these findings. The results indicated that BCs released considerably couple with the changes in starch properties caused by MAse enhanced the effectiveness of this product to diabetes as well as positive effect on cytotoxic activity against HepG2 cell.

Improvement of germinated brown rice quality with autoclaving treatment

Germinated brown rice (GBR) is a popular functional food containing considerable amounts of beneficial nutrients and bioactive compounds. Here, autoclaving at 115°C for 20 min was employed to process GBR (AGBR) to evaluate the effect of autoclaving on the nutritional and health function of GBR in microstructure, taste value, aroma, as well as the physiological ingredients. The results showed that autoclaving treatment influenced the starch gelatinization and aroma to improve the taste of cooked AGBR. Autoclaving treatment significantly increased the gamma‐aminobutyric acid (GABA) and ferulic acid levels of AGBR (p < .05). In addition, consuming AGBR for 1 month significantly decreased the fasting plasma glucose (FPG), 0.5, 1, and 2 hr postprandial plasma glucose (PPG), triglyceride (TG), total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐c), and low‐density lipoprotein cholesterol (LDL‐c) in metabolic syndrome (MS) patients (p < .05). Therefore, autoclaving treatment, as a promising processing strategy, may both improve the sensory attributes and the nutrition of GBR.