Changes in rice bran bioactives, their bioactivity, bioaccessibility and bioavailability with solid-state fermentation by Rhizopus oryzae

The growing demand for aquaculture has driven the search for sustainable practices and utilization of agro-industrial residues. Brown rice bran, an abundant and low-cost by-product, has emerged as a promising raw material. This dissertation aimed to evaluate solid-state fermentation (SSF) of rice bran using the fungus Rhizopus oryzae and the yeast Saccharomyces cerevisiae with the goal of improving its nutritional value for use in diets formulated for zebrafish (Danio rerio). Proximate composition analyses revealed the strong biotransformation potential of Rhizopus oryzae. Fermentation with this fungus resulted in a significant 36.45% increase in protein content, a 51.62% increase in total polyphenols, and a 13.7% reduction in lipid content. In an in vivo experiment, zebrafish fed a diet containing rice bran fermented by R. oryzae showed the best zootechnical performance, with higher weight gain, specific growth rate, and improved feed conversion. Gene expression analysis showed a significant difference only for glut6, which is related to glucose transport. In summary, the fermentation of brown rice bran with Rhizopus oryzae represents an effective strategy to enhance its nutritional profile, establishing it as a viable alternative for the formulation of more sustainable and efficient diets in aquaculture.

Effect of boiling on the total phenolic, anthocyanin and carotenoid concentrations of potato tubers from selected cultivars and introgressed breeding lines from native potato species

BACKGROUND: Andean berry contains several classes of phenolic compounds which have showed antioxidant and cytotoxic activity. OBJECTIVE: To characterize the Andean berry aqueous extract and to study their anti-proliferative mechanisms on SW480 and SW620 cell lines (human colon adenocarcinoma). METHODS: Total phenolic and total anthocyanins contents were determined by Folin-Ciocalteau and differential pH methods, respectively. Antioxidant activity was measured by FRAP, ORAC and DPPH methods. Antiproliferative effect was determined by sulforhodamine colorimetric method and apoptosis was analyzed by flow cytometry using propidium iodide/Annexin-V. Mitochondrial potential was evaluated using DIOC6 and ROS levels were measured by 2,7-Dicholorodihydrofluorescein diacetate (DCFH-DA). RESULTS: The total phenol and anthocyanin content were 4409.78± 63,05 mg equivalents of gallic acid/100 mL and 106,57± 1.43 mg equivalents of cyanidin-3-glycoside/100 mL, respectively. Andean berry extract showed antioxidant activity by FRAP, ORAC and DPPH methods and antiproliferative effect on SW480 and SW620 cells. It was observed a cell cycle arrest at S and G2/M phases on SW480 and at G0/G1 phase on SW620 cells. Aqueous extract did not induce mitochondrial depolarization or affect intracellular ROS levels. CONCLUSIONS: Andean berry aqueous extract has antioxidant capacity and induces apoptosis involving cell cycle arrest in SW480 and SW620 cells without mitochondrial damage.

Leafy sweet potato (Ipomoea batatas L.) is an excellent source of nutritious greens and natural antioxidants, but reports on antioxidants content and activity at buds, leaves, petioles, and stems are scarce. Therefore, the total phenolics content (TPC), total anthocyanins content (TAC), and antioxidant activity (assessed by DPPH and ABTS radical scavenging activities and ferric reducing antioxidant power (FRAP)) were investigated in four aerial parts of 11 leafy sweet potato varieties. The results showed that varieties with pure green aerial parts, independently of the part analyzed, had higher TPC, FRAP, and ABTS radical scavenging activities. The green-purple varieties had a significantly higher TAC, while variety GS-17-22 had the highest TAC in apical buds and leaves, and variety Ziyang in petioles and stems. Among all parts, apical buds presented the highest TPC and antioxidant capacity, followed by leaves, petioles, and stems, while the highest TAC level was detected in leaves. The TPC was positively correlated with ABTS radical scavenging activity and FRAP in all parts studied, whereas the TAC was negatively correlated with DPPH radical scavenging activity. Collectively, the apical buds and leaves of sweet potato had the higher levels of nutritional values. These results would provide reference values for further breeding of leafy sweet potatoes.

A comparison study between whole grain and rice bran to evaluate the antioxidant activity and starch digestion property of black rice was conducted. Total phenolics content (TPC) and total anthocyanins content (TAC) analysis found that TPC and TAC contribution of rice bran to the whole grain were over 73 and 91%, respectively. Cyanidin-3-glucoside with minor peonidin-3-glucoside were identified in all whole grain and rice bran samples by HPLC-ESI-MS. The rice bran exhibited much stronger antioxidant activities than the whole grain, acting as the major antioxidant contributor to the black rice due to the high levels of TPC and TAC. In vitro digestion analysis found that rice bran could significantly decrease the digestibility and predicted glycemic index (pGI) of rice flour by lowering the rapid digestion starch and increasing the resistant starch (RS). This study revealed that rice bran could be a potential edible resource of phenolic-enriched antioxidant and glycemic regulator in food industry.

Phytic acid is an antinutritional factor that forms 1–2% of most of the seeds and their co-products representing more than 60% of their total phosphorus. Monogastric and agastric animals are unable to utilize phytate phosphorus either due to lack of or insufficient amount of phytate degrading enzymes. Phytases (myo-inositol hexakisphosphate-phosphohydrolase) are a special class of phosphatases that catalyze the hydrolysis of phytic acid in a stepwise manner to lower inositol phosphates, myo-inositol and inorganic phosphate. Phytases are found naturally in plants and microorganisms and a sizeable number of phytases have been purified and characterized from various fungi, yeasts and bacteria. The present investigation involves studies on the effect of moisture content, pH value and different media ingredients such as carbon, nitrogen, and surfactants on the production of phytase by the fungus Aspergillus ficuum DSM 932 in solid-state fermentation (SSF) using rice bran as substrate. The production of phytase by SSF was favored, when the fungus was grown at a moisture content of 60% and pH 7.0, resulted in a phytase activity of 5.2 units/g dry substrate. There was a 20% increase in phytase yield in the presence of sucrose in SSF medium, while glucose and fructose were not effective in enhancing the phytase activity when used individually. Yeast extract was found to be a favorable nitrogen source for phytase production by SSF, which resulted in a 20% increase in phytase activity. There was no significant effect in increasing phytase production with the use of either soy peptone or tryptic soy as nitrogen source. Approximately 30% inhibition in phytase activity was shown in the presence of the surfactant Tween-80 or Triton X-100 in the SSF. By supplementing rice bran with sucrose and yeast extract, and performing the SSF in tray bioreactors, a phytase activity of 6.76 units/g dry substrate could be obtained. Keywords: phytase, solid-state fermentation, Aspergillus ficuum , nutritional factors, rice bran

This study was conducted to determine the effect of biodegradation on the nutrient contents of rice bran (RB), cassava residual pulp (CRP), saw dust (SD) and palm oil fibre (POF) by Penicilium sp. RB, CRP, SD and POF were subjected to solid state fermentation by Penicilium sp. for 7 days and the process was terminated by oven drying at 700C for 24hours. The fermented samples were thoroughly mixed, dried and stored in sterile bottles for analyses. Results of proximate composition before and after biodegradation revealed that percentage improvement in crude protein, ether extract, ash, and gross energy were significantly (P<0.05) higher in CRP compared to RB, SD and POF. Similarly, percentage reduction in crude fibre after biodegradation was highest (P><0.05) in CRP compared to other agro industrial wastes products. It was evident that solid state fermentation using Penicillium sp enhanced the crude protein value and reduced the crude fibre contents of rice bran, cassava residual pulp, saw dust and palm oil fibre thereby increasing nutrient availability and their utilization as feed alternative ingredients for farm animal nutrition. ><0.05) higher in CRP compared to RB, SD and POF. Similarly, percentage reduction in crude fibre after biodegradation was highest (P<0.05) in CRP compared to other agro industrial wastes products. It was evident that solid state fermentation using Penicillium sp enhanced the crude protein value and reduced the crude fibre contents of rice bran, cassava residual pulp, saw dust and palm oil fibre thereby increasing nutrient availability and their utilization as feed alternative ingredients for farm animal nutrition.><0.05) n CRP compared to other agro industrial wastes products. It was evident that solid state fermentation using Penicillium sp enhanced the crude protein value and reduced the crude fibre contents of rice bran, cassava residual pulp, saw dust and palm oil fibre thereby increasing nutrient availability and their utilization as feed alternative ingredients for farm animal nutrition.

Rice (Oryza sativa L.) is one of the leading food crops of the world, the staple food of over half the world's population. The bran, which is an important byproduct obtained during rice milling, constitutes about 1/10 of the weight of the rice grain. Rice bran is the outer brown layer including the rice germ that is removed during the milling process of brown grain. This milling byproduct is reported to be high in natural vitamins and minerals, particularly vitamin E. The present study was conducted to determine the chemical composition of bran and bran oil of 13 different rice varieties commonly produced in Egypt, to study the utilization of rice bran in bread production, and to assess the quality and acceptance of the rice bran edible oil produced. Rice bran was produced from 13 Egyptian varieties of recently harvested rice as well as from paddy rice stored for 1 year. The extracted bran was immediately stabilized then subjected to chemical analysis (such as moisture content, protein, fat, carbohydrates, fiber, and ash) as well as trace and heavy metals determination (P, K, Na, Ca, Fe, Zn, Cu, and Mg). Bread was produced by adding Giza172 rice bran at three different concentrations to wheat flour then subjected to chemical analysis, caloric content, and organoleptic examination. Bran oil was extracted from the different varieties of rice bran (recently harvested and stored) then subjected to chemical and organoleptic examinations as well as vitamin E and oryzanol determination. The percentage of rice bran of newly harvested Egyptian rice was 11.68% and was 10.97% in stored rice. The analysis showed mean values of 5.91 and 5.53% for moisture, 14.60 and 14.40% for crude protein, 14.83 and 15.20% for fat, 44.77 and 45.40% for carbohydrates, 6.55 and 7.06% for crude fiber, and 8.87 and 8.50% for ash for newly harvested and stored rice bran, respectively. Bread containing 15% rice bran showed the highest score percentages for organoleptic quality compared with the control (100% wheat flour). Rice bran oil showed higher scores of taste, smell, appearance, and texture than corn oil and sunflower oil. Rice bran contains high nutritional components as well as phytochemicals such as vitamin E (i.e. tocopherols and tocotrienols) and the γ-oryzanol fraction that have positive effects on human health. Storage of paddy rice before milling resulted in significant effect on all studied rice bran characters and rice bran oil characters under the present investigation except crude protein and carbohydrates characters. Substitution of wheat flour with rice bran by 15% in bread production to fortify the bread with vitamin E and to reduce the amount of imported flour is recommended.

Indonesia produced 56.54 million tons of paddy (Oryza sativa) dried grain in 2018, with rising demand leading to increased production of by-products such as rice bran. Rice bran, a nutrient-rich by-product, contains high levels of dietary fiber and bioactive compounds with notable anti-cholesterol and anti-diabetic properties. Numerous in vitro and in vivo studies highlight the antioxidant capabilities of rice bran, mainly due to tocopherol, γ-oryzanol, and β-carotene, which function as primary and secondary antioxidants. Effective extraction and fractionation techniques can isolate these antioxidants from rice bran. Cultivation practices significantly impact the nutritional composition of rice bran. The nitrate reductase enzyme (NRA) test can assess growth conditions, which may reflect metabolic activity in paddy plants. Enhanced dietary fiber components (hemicellulose, cellulose, and lignin) and niacin levels make rice bran a promising alternative nutrient source in Indonesia, where unhealthy lifestyles are prevalent. With Indonesia’s significant rice production and bran demand, processed rice bran products hold substantial potential as functional foods for routine consumption, promoting a healthier diet and aiding in prevention of degenerative diseases.

Arrowroot as a novel substrate for ethanol production by solid state simultaneous saccharification and fermentation

Rice bran is a by-product of the milling process that contains compounds with possible therapeutic properties. However, it is underutilized. This study assessed the phytochemical content, namely free, bound, and total phenolic (TPC), flavonoid (TFC), and anthocyanin (TAC) contents; antioxidant capacity using the 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging assay; and in vitro antibacterial activity of crude extracts from the bran of six (one white, two red, three black) selected Philippine rice varieties. Cyanidin-3-glucoside (C3G) and trans-ferulic acid (TFA) were quantified through High-Performance Liquid Chromatography. The in vitro antibacterial activities of extracts (0.1, 0.5, and 0.7 g/mL) against the gram-positive food pathogens Staphylococcus aureus and Clostridium perfringens were evaluated by agar well diffusion assay. Of the five samples, the red rice Kamanga recorded the highest free phenolics (121.01 mg gallic acid equivalents (GAE)/g), TFC (90.14 mg rutin hydrate equivalents/g), and DPPH antioxidant capacity (368.23 µmol Trolox equivalents/g). Generally, black brans had higher TAC, especially Ominio (17.81 mg C3G equivalents/g), which also had the highest bound phenolic content (125.6 mg GAE/g). C3G was only detected on black brans, with at least six-fold more in Ominio than in the other tested varieties. Only the extracts from pigmented varieties, except Ominio, displayed inhibitory potential against the food pathogens, implying that C3G is not the major component imparting the inhibitory activity in the black rice varieties. Therefore, pigmented rice brans can be explored as cheap sources of phytochemicals with antioxidant capacities and natural antibacterial agents for the food and pharmaceutical industries.

Rice varietal differences in bioactive bran components for inhibition of colorectal cancer cell growth

SUMMARYResearch backgroundHeat-stabilised defatted rice bran (HSDRB) is a primary by-product of rice bran oil extraction industry and a nutritious source of protein. However, despite the unique nutritional profile of rice bran protein, the protein-rich by-product, HSDRB is underutilised as a low-value animal feed. Research on protein extraction from HSDRB by enzymatic hydrolysis has attracted the attention of numerous scientists. However, a cost-effective extraction method is required to mitigate the high costs associated with the use of enzymes. Therefore, we have presented an alternative economical and natural approach for protein extraction from HSDRB by solid-state fermentation (SSF) with heterofermentative microbes.Experimental approachSSF of HSDRB with two types of traditional Asian fermentation starters, namely loog-pang and koji, were evaluated for enzyme production and their efficacy in extracting proteins from HSDRB. For this purpose, HSDRB fermentation was carried out for 0, 12, 24, 48, 72 and 96 h followed by 24-hour hydrolysis to evaluate the extracted rice bran protein. In addition, microbiome diversity in the fermentation starters was also determined by metagenomic sequencing of 16S rRNA and internal transcribed spacer to identify bacteria and fungi, respectively.Results and conclusionsThe microbial community in the fermentation starters showed the dominance of lactic acid bacteria (LAB) such as Bacillus subtilis in loog-pang and Streptococcus lutetiensis, Bacillus pumilus, Lactococcus cremoris, Lactococcus garvieae and Pediococcus pentosaceus in koji, while yeast species Saccharomycopsis fibuligera and Saccharomyces cerevisiae dominated the fungal diversity in loog-pang and koji starters, respectively. The results suggest that loog-pang and koji can produce cellulase, neutral and acid proteases during fermentation. Despite the discrepancy in their microbial diversity and the enzyme activity during SSF, both starters could effectively increase protein extraction from HSDRB. A positive relationship between the SSF duration and extracted protein was observed. During SSF with loog-pang and koji after 72 h followed by 24-hour hydrolysis, 65.66 and 66.67 % protein was extracted from HSDRB, respectively. The amino acid analysis of the protein hydrolysate produced by the non-fermented and fermented methods showed no difference and had an abundance of glutamic and aspartic acids, leucine, arginine, alanine and glycine amino acids, which accounted for approx. 58 % of the total amino acids.Novelty and scientific contributionLoog-pang and koji (traditional Thai and Japanese fermentation starters, respectively) were found to be effective in extracting proteins from HSDRB by SSF although they are inexpensive microbial enzyme sources. Future research aimed at scaling up HSDRB protein extraction for usage in industrial applications can draw on our results.

Sustainable production of high-quality chitosan from agro-industrial by-products remains a challenge in biotechnology. This study aimed to improve chitosan production from fermented rice bran and rice husk using Rhizopus oryzae in solid-state fermentation (SSF), and evaluated the physicochemical and biological properties of the resulting biopolymer. A full factorial design (23) was applied to assess key fermentation parameters, including moisture content, substrate composition, and nitrogen supplementation. Among the tested conditions, the highest chitosan yield was at 55% moisture, 50% rice husk, and 1.8 g/L urea. The obtained chitosan was characterized for degree of deacetylation (DD) using FTIR and NMR, and molecular weight (MW) by viscometry. Antimicrobial activity was tested against Gram-positive and Gram-negative bacteria, and antioxidant capacity was measured via DPPH and ABTS assays. The chitosan exhibited a high DD (86.4 ± 0.6%) and a MW of 59.65 kDa, values comparable to commercial standards. It showed strong antimicrobial activity, particularly against Gram-negative strains. Antioxidant assays confirmed concentration-dependent activity, reaching 94% DPPH inhibition at 5.00 mg mL−1. Overall, the results demonstrate that agro-industrial residues can be effectively transformed into high-quality, bioactive chitosan, offering a sustainable and circular alternative to conventional production routes.

The effect of temperature, moisture content and pH during solid-state fermentation (SSF) of MD2 pineapple peel with Rhizopus oryzae (MUCL 28168) was evaluated on the release of bioactive compounds with antioxidant capacity. Applying a central composite design, it was found that temperature had a significant effect (p < 0.05) on the total phenolic content and DPPH antioxidant activity while for the ABTS radical elimination activity, the factor that presented a significant effect was the pH (p < 0.05); as this factor increases, the antioxidant activity enhances. The optimal conditions for fermentation process were 80% of moisture content, pH 5.5, temperature 37.3 °C and 24 h of process to maximize phenolic content and antioxidant activity. Gallic acid, chlorogenic acid, caffeic acid and cinnamic acid were identified in the extracts by HPLC analysis. These results permit to conclude that SSF of pineapple peel is an effective bioprocess for the release of phenolic compounds with antioxidant activity.Graphical abstract