Black Rice Research Articles

Total Deoxynivalenol Contamination of Wheat Products and Coarse Grains in Shanghai, China: Occurrence and Health Risk Assessment

Deoxynivalenol (DON) is an important mycotoxin produced by Fusarium spp., typically found in cereals, which has garnered considerable research attention. However, the risk assessment of DON exposure to muti-cereal is partial and biased, especially lacking the evaluation of different coarse grains. In this study, we synthesized and compared the presence of the total deoxynivalenol (free, acetylated, and masked) of a total of 372 grain samples (17 different types) based on high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS), as well as assessed the chronic and acute risks of total DON exposure in the Chinese population. DON was found at the highest frequency with an occurrence of 85.8% (319/372), followed by D3G at 17.2% (64/372). In total, 88.7% (330/372) of the grains were co-contaminated with mycotoxins. The DON and D3G contamination correlation coefficient was 0.68 in wheat flour. Moreover, different DON contamination levels were found in black beans (133.5 µg/kg), soybeans (128.7 µg/kg), and black rice (122.1 µg/kg). The DON/D3G/15A/tDON contamination level was significant differently among different coarse grains. Notably, the Monte Carlo model showed that 3.2–5.9% of adolescents consuming wheat flour and noodles suffered a chronic tDON risk.

Trichoderma thailandense sp. nov. (Hypocreales, Hypocreaceae), a new species from Thailand

A new species of microfungus, described herein as Trichoderma thailandense was isolated from the pileus surface of oyster mushroom and upland black rice samples in Thailand. This species is described using morphological characteristics and molecular multi-gene analyses. Based on multi-gene phylogenetic analyses of the internal transcribed spacer (ITS) region of the rDNA, RNA polymerase subunit II gene sequences (rpb2), and translation elongation factor 1-α (tef1-α) gene revealed that the position of T. thailandense is well-supported within Harzianum clade of the genus Trichoderma, but distinct from other all other known species. A full description, illustrations and a phylogenetic tree showing the position of T. thailandense are provided.

Rapid Method for Simultaneous Determination of γ-Oryzanol Compounds in Rice (Oryza sativa) Grains using UV-Vis Spectroscopy and Chemometrics

Rice (Oryza sativa) contains γ-oryzanol, which consists of 4 main compounds: Cycloartenol ferulate, 2,4-methylenecycloartanyl ferulate, campesterol ferulate, and β-sitosterol ferulate, that contribute to the health benefits of rice. This research aimed to develop a rapid method to determine the 4 major γ-oryzanol compounds in 45 varieties covering pigmented (black and red) and non-pigmented (white) rice grain. The method was developed by integrating UV-Vis spectroscopy with chemometrics, specifically principal component analysis (PCA) and partial least square (PLS) regression. Sampling was performed across the Indonesian archipelago collecting 180 samples, which comprises 60 samples for each type of rice in form of rice husk, bran, whole grain, and polished rice. The results of PCA on the spectroscopic data successfully identified distinction for the 3 types of rice attributable by different type and levels of chemical compound in the grain. White rice exhibited a characteristic absorption at 325 nm while in pigmented (red and black) rice showed a maximum absorbance at 280 nm, indicating the presence of different composition of chemical compounds. A reliable model to predict the 4 major γ-oryzanol compounds was established with R2 calibration, R2 cross-validation, and R2 prediction higher than 0.9 was obtained using the spectroscopic data in the range from 200 to 400 nm. However, the PLS modeling was unsuccessful for red and black rice samples most likely due to the interfering high absorption of red colored compounds. Compared to the existing techniques for analyzing individual compounds of the γ-oryzanol by high-performance liquid chromatography, the newly developed approach using UV-Vis spectroscopy combined with chemometrics is more practical, faster, and cost-efficient and mainly, solvent and residues free. HIGHLIGHTS A rapid method was developed to determine 4 major γ-oryzanol compounds in rice. This method integrates UV-Vis spectroscopy with PCA and PLS regression chemometrics. PCA successfully identified the distinction among white, red, and black rice types. Reliable PLS models were established for white rice with R2 values above 0.9. The developed approach is more practical, faster, and residue-free than HPLC. GRAPHICAL ABSTRACT

Effect on Rheological Behavior and Composition of Wheat Cookies Fortified with Black Rice (Chakhao) Flour

ABSTRACT Black rice, known for its high anthocyanin and antioxidant content, is native to Asian countries like Japan, China, Thailand, India, and Indonesia. In India, it is primarily grown in Manipur, Assam, and Meghalaya, where it is called Chakhao. Despite its health benefits, black rice remains underutilized in food processing. This study examined the rheological behavior of Chakhao black rice flour blended with wheat flour (BR1, BR2, BR3) using alveograph and mixograph tests. BR3 showed the best baking properties, with a G value of 17.5 and p value of 90 mm H₂O, indicating its suitability for baking, especially cookies. Nutritionally, BR3 cookies were rich in protein (10.4%), fiber (2.91%), and minerals (2.95%). High starch retrogradation limits use in bread and biscuits. BR3 cookies are sensory-acceptable and can be marketed as healthy, functional products. Future research could focus on improving taste while maintaining health benefits.

Comparative Effects of Extracts from Black Rice or Pathum Rice Combined with Cereals on Blood Glucose Levels, Serum Insulin Levels and Blood Chemistry in Diabetic Rats

Rice is one of the major cereal crops in several Asian countries. It contains a variety of nutrients and provides valuable health benefits. The antidiabetic activity of rice combined with cereals has not been studied. Therefore, the present study was carried out to determine and compare the effects of extracts from Black rice (BRE), Pathum rice (PTRE), Black rice combined with cereals (BRCE), and Pathum rice combined with cereals (PTRCE) on body weight, blood glucose levels, serum insulin levels and blood chemistry of Streptozotocin (STZ)-induced diabetic rats. The results revealed that BRCE exhibited the highest activity in reducing fasting blood glucose (FBG) levels and increasing serum insulin levels, and also recovered the lipid profiles, renal function and hepatic function resulting from STZ in the diabetic rats, followed by BRE, PTRCE and PTRE, respectively. Also, BRCE exhibited an activity with similar potential to Glibenclamide. The findings indicate that the rice extracts possess antidiabetic activity which exerts the activity by increasing serum insulin resulting in reduction of blood glucose. Rice combined with cereals provides better antidiabetic activity and could be a source of valuable antidiabetic materials. HIGHLIGHTS Extracts from Black rice and Pathum Thani fragrant rice exhibit antidiabetic activity in Streptozotocin-induced diabetic rats. Antidiabetic activity of the extracts from Black rice and Pathum Thani fragrant rice is due to an increase in insulin secretion. Black rice exhibits antidiabetic activity higher than Pathum Thani fragrant rice. Combination with cereals could enhance the antidiabetic activity of rice. The extracts from Black rice and Pathum Thani fragrant rice may be useful for the management of diabetes mellitus. GRAPHICAL ABSTRACT

Workability and Environmental Evaluation of Using Sunflower Stalk Ash as an Alkali Activator with Blast Furnace Slag and Black Rice Hull Ash to Prepare Geopolymer Grouts

Workability and Environmental Evaluation of Using Sunflower Stalk Ash as an Alkali Activator with Blast Furnace Slag and Black Rice Hull Ash to Prepare Geopolymer Grouts

The Effect of In Vitro Digestion on the Anti-allergic, Anti-Inflammatory and Antioxidant Properties of Purple Rice and Purple Barley Phenolic Extracts in Caco-2 and RBL-2H3 Cells

Gastrointestinal diseases are associated with increased oxidative stress and inflammation. Pigmented cereal polyphenols are believed to have therapeutic potential. However, the impact of digestion on their bioactivity has not been fully elucidated. This study investigated the impact of digestion on the ability of purple rice extract (PRx) and purple barley (PBx) to alleviate oxidative stress-induced intestinal epithelial cell death and allergic inflammation. The study used a human colon adenocarcinoma (Caco-2) cell line to simulate intestinal oxidative stress for 4 h using 1 mM hydrogen peroxide. To evaluate the protective effects of digested and undigested cereal extracts, cells were first pre-treated with varying concentrations (50, 100, 200, and 500 μg/ml) of both purple rice (PRx) and purple barley (PBx) extracts. A rat basophilic leukemia (RBL-2H3) cell line was used to investigate the ability of the extracts to prevent calcium ionophore-induced histamine and cytokine release. The results demonstrated that both digested and undigested phenolic extracts prevented oxidative stress-induced cell death in Caco-2 cells and reduced Interleukin (IL)-8 secretion. PRx showed greater cytoprotective effects than PBx. Both digested and undigested extracts showed a time-dependent antihistamine effect, with the greatest inhibitory effects observed after 2 h and 4 h of treatment with PRx. Additionally, the extracts significantly attenuated the release of several cytokines including IL-2, IL-4, IL-13, monocyte chemoattractant protein-1, interferon-gamma, and tumour necrosis factor-alpha. Overall, the study demonstrates that both digested and undigested pigmented rice and barley extracts are potential sources of polyphenols which may promote intestinal health and alleviate allergic inflammation.

Evaluating the Antioxidant Activity and Stability of Pigmented Rice Extract

This study aims to evaluate the antioxidant activity and stability of the extract of pigmented rice. Pigmented rice powder from 6 different varieties including Subang, Jowo Melik, Andel Abang, Bukittinggi, Cempo Merah, and Cempo Ireng) was macerated using ethanol with concentrations of 96% and 70%. Next, the rice extract was tested for stability to pH (1, 3, 5, 7, 9) and temperature (20°, 40°, 60°, 80°C). Results revealed that extract of Subang black glutinous rice using 96% ethanol resulted the highest antioxidant activity of 11.11±2.04 mg FeSO4/g, with an overall anthocyanin, flavonoids, phenolic contents of respectively 28.22±1.14 mg CE/g, 2.91±1.13 mg QE/g, and 3.46±1.59 mg GAE/g. The physiochemical properties of the rice extract were affected by the difference of pH. The increase in pH resulted in a decrease in antioxidant activity, total anthocyanin, and the values of color attributes (L*, a*, b*, C*, and ºHue) of the rice extracts. Temperature did not affect the physiochemical properties of the extract. The antioxidant activity, total anthocyanin, and color attributes of the rice extract were typically stable when the temperature rose from 20°C to 80°C. The extract at pH 1 and 80ºC treatment exhibited slightly higher yield based on antioxidant activity, total anthocyanin content, a* value, and ºHue with the values of 16.92±1.73 mg FeSO4/g, 33.90±2.33 mg CE/g, 21.55±0.54, and 30.04±0.57, respectively. Keywords: Anthocyanin, antioxidant activity, pH, pigmented rice, temperature.

Intelligent color changing packaging film based on esterified starch and black rice anthocyanins

Intelligent packaging film has received more and more attention because it can help consumers obtain more intuitive information about the packaging, provide better preservation and advanced convenience. In this study, black rice anthocyanin (BRA) was added into composite film formed by starch (S) and esterified starch (ES). As the BRA content increased, the thickness and the total color difference of the S/ES-BRA film increased. The opacity of S/ES-BRA film decreased relative to that of the film without BRA, but increased with the increase of anthocyanin. Compared with S/ES film, the elongation at break of S/ES-BRA0.5 film increased from 33.1 % to 45.4 %, and the tensile strength decreased from 7.3 to 5.8 MPa. S/ES-BRA film had response to different pH values and underwent color changes in different buffer solutions. Intelligent color changing packaging film will used to monitor food quality, water quality and soil properties.

Transcriptome analysis of the coexpression network of genes related to antioxidant characteristics after grain filling in purple rice

Antioxidant capacity is an important indicator for evaluating the growth and developmental quality of rice. This study has guiding significance for the cultivation of high-nutrient-value varieties. To investigate the molecular mechanisms underlying the antioxidant characteristics of rice grains after the filling stage, Yangzinuo 1 (YZN1) was used as the experimental material, and grains collected at five different time points (7 days apart) after the filling stage were used for transcriptome sequencing. Through weighted gene coexpression network analysis (WGCNA), a coexpression network of gene weights related to antioxidant characteristics was constructed. LOC_Os10g39140, LOC_Os10g38276, and LOC_Os05g45740 were identified from the 2 modules showing the highest correlations with the target traits. GO functional annotation showed that target modules were enriched in pathways related to phenylalanine, flavonoids, and other related pathways, such as GO:0006558, GO:0006559, GO:0009812, and GO:0009813. Correlation analysis with metabolites revealed that differentially expressed genes were significantly enriched in pathways related to antioxidant characteristics and energy metabolism processes, such as glycolysis/gluconeogenesis and flavonoid biosynthesis. The core genes identified in this study were found to be highly correlated with antioxidant characteristics and enriched in pathways related to metabolic and energy pathways and molecular activities. These results provide an effective dataset supporting breeding targeting functional rice characteristics.

Cytotoxic Effect of Bajong LN Rice Methanol Extract on Human Squamous Cell Carcinoma, ORL-48

Oral squamous cell carcinoma (OSCC), a major oral cancer, significantly challenges treatments and impacts patient quality of life; current therapies often cause severe side effects, highlighting the urgent need for gentler alternatives. Rice stands as one of the primary cereal grains providing the daily caloric intake for more than half of the global population. Extensive research has demonstrated the significant health benefits derived from rice, attributed to its abundance of bioactive compounds. This study endeavours to explore the potential cytotoxic effects of Bajong LN rice, a pigmented purple rice indigenous to Sarawak, on human squamous cell carcinoma, ORL-48 cells. Cells were cultured in complete DMEM/F-12 media and incubated under standard culture conditions. Upon reaching 80% confluency, the cells were treated to varied concentrations (ranging from 0 μg/ml to 2000 μg/ml) of Bajong LN rice methanol extract (BLN-ME) and cisplatin. Subsequently, the cells were incubated for 48 and 72 hours, and their cytotoxicity was assessed using the MTS assay. Results demonstrated that cisplatin inhibited ORL-48 cells with an IC50 of 7.483 μg/ml and 3.877 μg/ml; and an IC80 of 40.649 μg/ml; and 17.543 μg/ml for 48 and 72 hours, respectively. Correspondingly, BLN-ME exhibited a notable cytotoxic effect against ORL-48 cells at 48- and 72-hour intervals, with an IC50 of 354.4 μg/ml and 342.0 μg/ml; and an IC80 of 450.3 μg/ml and 423.63 μg/ml, respectively. The cytotoxic activity of BLN-ME against ORL-48 cells was observed in both a time and dose-dependent manner. Morphological analysis and the Trypan blue exclusion assay corroborated the MTS assay's findings. Our preliminary findings provide the first scientific evidence of the cytotoxic effect of BLN-ME specifically against human squamous cell carcinoma, ORL-48 cells. This study suggests the potential of BLN-ME as a promising anti-cancer agent, presenting opportunities for further investigation into its underlying cytotoxic mechanisms.

Effect of Integrated nutrient management practices on nutrient uptake, yield and quality of improved black kavuni rice variety (CO57)

The rising demand for high-quality rice and rice products motivates farmers to produce traditional rice varieties. Rice production needs to be substantially increased with suitable nutrient management practices to meet the demand. Hence, the present study was carried out to evaluate the influence of integrated nutrient management practices on nutrient yield and quality of improved black kavuni rice. The research was conducted during the Early kar (April-August 2023) and Late samba (September - January 2023-24) seasons in a randomized block design (RBD) with three replications and twelve treatments consisting of N in equivalent basis with organic manure and inorganic fertilizers and one control. Based on an N equivalent basis, the required quantity of inorganic fertilizer, farmyard manure (FYM), vermicompost (VC) and poultry manure (PM) were applied to rice. Observations on nutrient uptake, yield and quality were recorded, and the data were analyzed using LSD at a 5% probability level for significance differences. The results revealed that higher nutrient uptake, yield and quality parameters of rice were recorded with 50% recommended dose of nitrogen through inorganic fertilizer + 50% recommended dose of nitrogen through VC + foliar spray of 0.5% ZnSO4 & 1% FeSO4 at tillering, panicle initiation (PI) and flowering stage (T11).

Effect of Colchicine and Bio-catharantin on the DNA Relative Content and Stomatal Structure of Black Rice (Oryza sativa L. var. Jeliteng)

<p>Black rice (<em>Oryza sativa</em> L. var. Jeliteng), known for its health benefits compared to white rice, faces challenges in productivity. Among varieties, this black rice is popular in Indonesia but shows low yield. Research on improving black rice through genetic manipulation with antimitotic substances is limited. Therefore, this study aims to compare the effects of colchicine and Bio-catharantin on the germination rate, DNA relative content, and stomatal structure of <em>O. sativa </em>L. var. Jeliteng. Seeds were treated with colchicine (0.1%, 0.2%, and 0.3%) and Bio-catharantin (0.1%, 0.2%, 0.3%, 0.4%, and 0.5%) at soaking durations of 12, 24, and 48 hours. Germination was assayed, ploidy was determined using flow cytometry, and stomatal traits, including size and density, were examined microscopically. The results showed that Bio-catharantin did not exhibit any toxic effects on germination rates, whereas colchicine reduced germination starting at 0.2% concentration. Both chemical agents modified the DNA relative content of Jeliteng black rice. Colchicine generally increased stomatal length and width while decreasing stomatal density, with significant changes at 0.3% concentration for 24 hours. Bio-catharantin also altered stomatal traits, enhancing length and width in most cases but significantly reducing density under certain conditions. Bio-catharantin emerged as a promising alternative to colchicine for inducing chromosomal mutations in plants, offering benefits in altered stomatal structures without the toxic effects on germination, compared to colchicine.</p>

Black rice bran extract exerts hepatoprotection via attenuating inflammation and apoptosis in obese-insulin-resistant rats

Global pandemic of obesity contributes to increasing the risk of diabetes and non-alcoholic fatty liver disease (NAFLD). To find an alternative approach to lower the risk caused by obesity. AimsWe investigated the antidiabetic and hepatoprotective activity of black rice bran extract (BRE) in obese, insulin-resistant rats induced by a high-fat diet (HFD). Main methodsAfter HFD feeding, the parameters related to glucose, lipid profiles, and liver injury were determined. Key findingsRats on a HFD exhibited significantly elevated plasma glucose and lipid levels, as well as increased liver enzyme activities (aspartate transaminase and alanine transaminase), relative to the control group. Interestingly, those parameters in the BRE-treated group were significantly decreased. We investigated the liver histological study, and the BRE-treated group showed to ameliorate the liver injury accompanied by lower inflammatory and apoptotic markers. SignificanceOur findings suggest that BRE has the potential to be used as a dietary supplement to lessen metabolic dysregulation and prevent liver impairment.

Determination of fertilizer requirement of Indonesian black rice in winter season under different plant spacing at Agro-ecological Zone-9 of Bangladesh

Indonesian black rice is quite popular for its highly nutritive value and profitable production. The distinct knowledge about optimum fertilizer doses and plant spacing contributes to its promising yield. The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, from December 2022 to May 2023 to find out the effect of fertilizer management and plant spacing on the growth and yield of Indonesian black rice in the winter season. The experiment was conducted with 5 treatments of fertilizer management viz., F1(70% of recommended doses); F2(80% of recommended doses); F3(90% of recommended doses); F4(100% of recommended doses) and F5(110% of recommended doses) with 4 plants spacing viz., S1(20 cm × 15 cm); S2(20 cm × 20 cm); S3(25 cm × 15 cm) and S4(25 cm × 20 cm). The experiment was laid out in a split-plot design where the fertilizer management was allocated in main plots and the plant spacing was distributed in sub-plots with three replications. The result revealed that the fertilizer doses and plant spacings along with the interaction effects significantly influenced the growth and yield parameters of Indonesian black rice. Regarding vegetative growth, plant height (79.3cm), total tiller plant-1(21.27cm), and total leaf number plant-1 (58.47) were maximal at 100% recommended dose of fertilizer(F4) at DAT 65. Similarly, S2(20 cm × 20 cm) had better result in crop growth and yield attributes. The interaction effects of the treatments showed significant impact on plant height, total tiller and leaf number where F4S2 gave satisfied results. The highest values for the yield parameters including the maximum number of grains panicle-1 (100.70), 1000-grain weight (28.33g), and grain yield (5.69g) were found from the combination treatment of F4S2. On the other hand, the lowest grain (3.68g) yield was found from F1S4. Therefore, observing the results of the experiment, the best consideration was F4S2 at Agro-ecological Zone-9 in the winter season for the desirable growth and yield of Indonesian black rice.

Computational insights into the inhibitory mechanism of type 2 diabetes mellitus by bioactive components of Oryza sativa L. indica (black rice).

Type 2 diabetes mellitus is a metabolic disease categorized by hyperglycemia, resistance to insulin, and ß-cell dysfunction. Around the globe, approximately 422 million people have diabetes, out of which 1.5million die annually. In spite of innovative advancements in the treatment of diabetes, no biological drug has been known to successfully cure and avert its progression. Thereupon, natural drugs derived from plants are emerging as a novel therapeutic strategy to combat diseases like diabetes. The current study aims to investigate the antidiabetic potential of natural compounds of Oryza sativa L. indica (black rice) in disease treatment. Antioxidant activity and alpha amylase assays were performed to evaluate the therapeutic potential of the extract of Oryza sativa L. indica. Gas chromatography-mass spectrometry (GC-MS) was used for identification of constituents from the ethanol extract. ADMET profiling (absorption, distribution, metabolism, excretion, and toxicity), network pharmacology, and molecular dynamics simulation were employed in order to uncover the active ingredients and their therapeutic targets in O. sativa L. indica against type 2 diabetes mellitus. GC-MS of the plant extract provided a list of 184 compounds. Lipinski filter and toxicity parameters screened out 18 compounds. The topological parameters of the protein-protein interaction (PPI) were used to shortlist the nine key proteins (STAT3, HSP90AA1, AKT1, SRC, ESR1, MAPK1, NFKB1, EP300, and CREBBP) in the type 2 diabetes mellitus pathways. Later, molecular docking analysis and simulations showed that C14 (1H-purine-8-propanoic acid, .alpha.-amino-2, 3, 6, 7-tetrahydro-1,3,7-trimethyl-2,6-dioxo-) and C18 (cyclohexane-carboxamide, N-furfuryl) bind with AKT1 and ESR1 with a binding energy of 8.1, 6.9, 7.3, and 7.2kcal/mol, respectively. RMSD (root-mean-square deviation) and RMSF (root-mean-square fluctuation) values for AKT1 and ESR1 have shown very little fluctuation, indicating that proteins were stabilized after ligand docking. This study suggests therapeutic drug candidates against AKT1 and ESR1 to treat type 2 diabetes mellitus. However, further wet-lab analysis is required to discover the best remedy for type 2 diabetes mellitus.

Effects of Media and Processes on the Aromas of White Truffle Solid-State Fermented Products

This study aimed to formulate a black bean soy sauce using black beans and black rice as media for the solid-state fermentation of white truffle. Various proportions of these media (4:0, 3:1, 2:2, 1:3, and 0:4) were prepared, with methionine concentrations (0, 0.3, 0.6, 0.9, 1.2, and 1.5%) serving as precursors for a 4-week solid-state fermentation to analyze the aroma profiles. GC-MS analysis showed that samples with 1.5% methionine exhibited significantly higher levels of sulfur-containing volatile compounds compared to those without methionine. GC-IMS analysis revealed that a 2:2 ratio of black beans to black rice produced the most enriched aroma. Lower methionine levels improved mycelial growth, with 0.3% methionine yielding the richest aroma components. After fermentation, the white truffle products were sterilized using autoclaving, hot air assisted radio frequency (HARF), and high pressure processing (HPP), followed by freeze drying. GC-IMS analysis showed that HPP samples had an aroma closest to fresh samples, whereas HARF and autoclave resulted in similar aromas. However, 24 h freeze drying significantly diminished the aroma, resulting in no significant difference in aroma among the freeze-dried products treated with different sterilization methods.

FLAVONOID AND ANTIOXIDANT ACTIVITY ANALYSIS OF ANTHOCYANIN BLACK RICE BRAN EXTRACT (ABRIBE) CV CEMPO IRENG ORIGIN FROM INDONESIA

Black rice is an indigenous food in Indonesia that is rich in anthocyanins, a group of plant pigments that are also found in berries. Despite the similarity in anthocyanin content, the high cost and limited availability of berries have restricted their use for extraction. Therefore, this study aimed to determine the total anthocyanin, flavonoid content, and antioxidant activity of black rice bran. To achieve this, the extraction was conducted with maceration using ethanol-citric acid and freeze-drying techniques. The process involved several stages, such as making black rice bran powder, maceration, homogenization, filtration, evaporation, and freeze-drying. The UV-Vis spectrophotometer was used to determine the total anthocyanin and flavonoid content, as well as antioxidant activity. The result showed a total anthocyanin content and the total flavonoid content of 2.48 ± 0.17 mg/gram and 3.76 ± 0.000 mg QE/g freeze-dried extract, respectively. Furthermore, the antioxidant activity of black rice bran CV Cempo Ireng extract and ascorbic acid as a standard was measured in terms of half maximal inhibitory concentration (IC50) in the form of percentage inhibition (%I), with values of 112.42 ± 2.368 and 7.18 ± 0.042 μg/mL, respectively.

The preservative effect of the black rice's cold, hot and ultrasonic ethanol extracts on the storage quality of beef patties

SummaryThis work aimed to determine the total anthocyanin and phenolic contents and antioxidant capacity of extracts of the black rice's cold, hot and ultrasonic‐assisted extracts and their preservative effect on the storage quality of beef patties. The three extracts exhibited high anthocyanin, phenolic content and antioxidant capacity, and they were used in beef patties at five treatments (negative control without extract, positive control with 0.01% butylated hydroxytoluene (BHT), 7.5% cold extract, 7.5% hot extract and 7.5% ultrasound‐assisted extract). Raw and cooked beef patties were tested at 0, 3, 6, 9 and 12 days of cold storage in aerobically packaged polyethylene containers regarding pH, oxidative stability, antioxidant capacity and microbial quality. While adding black rice extracts did not influence the proximate composition of raw samples (P > 0.05), it slowed down the pH and lipid oxidation during storage and provided pH and thiobarbituric acid reactive substances (TBARS) stability in all final products. The BHT and treatments with extract indicated a higher 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) value than the negative control. Also, the incorporation of black rice extracts slightly retarded bacterial growth. These results suggest that the black rice extracts at 7.5% can be used effectively to protect beef patties from microbial spoilage and oxidation during cold storage for 12 days.

Changes of polyphenols and their antioxidant activities in non-pigmented, red and black rice during in vitro digestion

Polyphenols, a major bioactive constituent in rice grain, require processing and digestion before being absorbed by human body. Free and bound phenolics, flavonoids and their antioxidant activities in non-pigmented, red and black rice after cooking and INFOGEST digestions of oral, gastric and intestinal phases were investigated. It showed that cooking caused great losses of polyphenols and antioxidant activity. Free ferulic, isoferulic and p-coumaric acid in most rice were highest at intestinal phase (p < 0.05). Bound ferulic acid in three colored rice, bound p-coumaric acid in black rice and catechin in red rice were higher at oral and/or gastric phase. After cooking, total flavonoids of non-pigmented and pigmented rice were highest at intestinal and gastric phase, respectively. Cyanidin-3-O-glucoside, peonidin-3-O-glucoside and quercetin peaked at intestinal phase in black rice. It suggested that black rice has a greater potential to be used in meal balance and functional product development.