Black rice (Oryza sativa L.) processing: Evaluation of physicochemical properties, in vitro starch digestibility, and phenolic functions linked to type 2 diabetes

Amelioration of aging-induced muscular decline by black soybean (Rhynchosia nulubilis) and black rice (Oryza sativa L.) extracts

Aging leads to a decline in the mass and function of skeletal muscles, a condition known as sarcopenia. It was previously reported that aging-related alterations in protein degradation, chronic inflammation, and deterioration of mitochondrial metabolism affect the acceleration of muscle atrophy in the elderly. However, the detailed mechanism or substantial causes for age-related muscle loss are still lacking, yet exercise or an increment in dietary protein intake are suggested as effective approaches to mitigate muscle atrophy. This study aims to investigate the regulatory effect of black soybean (Rhynchosia nulubilis) and black rice (Oryza sativa L.) mixture extract (BBME), which are rich in protein and bioactive compounds, in 12-month-old aged mice and L6 myotubes. BBME was orally administered at 300 and 600 mg/kg/day (low and high doses) for 12 weeks, and its effects on systemic glucose homeostasis and skeletal muscle metabolism were evaluated. Consequently, BBME at a high dose marginally ameliorated muscle loss and significantly improved glucose metabolism. BBME also reduced cellular senescence markers and enhanced mitochondrial biogenesis in aged skeletal muscles. Additionally, BBME exerted insulin-like activity by promoting glucose metabolism in L6 myotubes. These findings suggest the potential of BBME as a functional food ingredient in alleviating aging-induced muscle loss by modulating mitochondrial activity and glucose metabolism.

Impact of flour particle size on digestibility and gut microbiota modulation in brown rice noodles: Balancing cell wall disruption and starch damage

Brown rice noodles are recognized for their health benefits. While previous research has focused on improving noodle properties through various processing conditions, the effects on digestibility and fermentability remain unclear. This study comprehensively investigated how brown rice flour particle size influences noodle digestibility and gut microbiota fermentation in vitro. Particle size first affects flour properties. The average particle size of BR15 flour (62 μm) falls between the length and width of the endosperm cells, effectively disrupting the cell walls while minimizing excessive starch damage, thus achieving an optimal balance and resulting in the highest peak viscosity. As a result, brown rice noodles made from BR15 flour exhibited the lowest starch digestibility in vitro. X-ray diffraction analysis revealed that starch crystals in digestive residues were predominantly V-type, with BR15 showing the highest relative crystallinity. In vitro fecal fermentation indicated elevated Bifidobacterium abundance and butyrate production for BR15 noodles compared to others. The moderate particle size of BR15 brown rice flour imparts unique digestibility and gut microbiota modulation to the noodles produced. This study provides insights into particle size optimization for improving nutritional quality of brown rice noodles.

Black Gram (Vigna mungo L.) Husk as a Source of Bioactive Compounds: An Evaluation of Starch Digestive Enzyme Inhibition Effects

This research recovered bioactive compounds from black gram husk (BGH, a by-product of sprout processing) using different ethanol concentrations and maceration times. Based on the results, the highest phenolic and saponin contents were recovered using an 80% ethanolic solution for 3 h, with the extract having both antioxidant and starch digestive enzyme inhibition effects. The major bioactive compounds present in the extract were gallic acid, gentisic acid, ferulic acid, and vitexin. The extract from BGH had an effective binding affinity to α-glucosidase, resulting in a potent ability of the extract to delay enzyme activity. Based on in vitro starch digestion using cooked rice as a model, adding the extract (10 mg/mL) increased the resistant starch content (from 53.9% to 55.9%) and lowered the estimated glucose index (from 83.1% to 81.0%) as compared to the control without the extract. Based on the overall results, the BGH extract could be promising as a functional ingredient with antioxidant activity and the ability to control postprandial blood glucose levels in the development of healthy food products.

Comprehensive characterization of nutritional components in sweetpotato (Ipomoea batatas [L]. Lam.) during long-term post-harvest storage

To uncover the variation patterns of the nutritional components in sweetpotato storage roots during long-term storage comprehensively, the general nutrients, phytochemicals, and starch properties of nine sweetpotato varieties with different flesh colors were quantified and analyzed by chemical and physical techniques. During the storage, the starch content decreased firstly and then increased, with sugar content the opposite. The crude protein content and the total dietary fiber content both increased continuously. The β-carotene content decreased or kept constant, while the anthocyanin content showed different variation patterns in the three purple-fleshed varieties. The four types of polyphenols and two types of flavonoids showed no obvious content changes during the storage. The amylose contents of all varieties showed various patterns, while the crystallinity was C-type. The proportion of small-sized starch granules reduced, and the combined proportion of medium-sized and large-sized granules increased. New correlations among the nutritional parameters for each variety were revealed for the first time. Principal component analysis indicated that the orange-fleshed varieties were distinguished from other varieties. Finally, the most storage-resistant variety ZZ3 and the suitable variety for each quality trait was selected. This study provides not only theoretical basis for comprehensive understanding of the nutrient's variations in sweetpotato storage roots during long-term storage, but also guidelines for evaluation of nutritional quality of sweetpotato roots during storage and improvement of storage methods.

Ice cream cone fortified with spent coffee ground: Chemical composition, quality and sensory characteristics, and in vitro starch digestibility

The objective of the study was to evaluate the effect of the incorporation of spent coffee grounds in ice cream cones on the quality, sensory characteristics, and in vitro starch digestibility. The incorporation of spent coffee grounds in ice cream cones increased the content of dietary fiber and phenolic compounds. However, the quality and texture characteristics decreased with the addition of spent coffee grounds. The in vitro starch digestibility decreased significantly, resulting in a significant increase in resistant starch content. Fitting starch digestibility using the LOS-plot model revealed the presence of two sequential first-order digestion rates. Sensory analysis revealed that the panelists well accepted ice cream cones fortified with spent coffee grounds. The results suggest that spent coffee grounds are a potential ingredient for the formulation of food matrices with reduced starch digestibility, which contributes to the prevention of chronic degenerative diseases such as type II diabetes.

Boosting resistant starch in rice: Bacterial inulin as a metabolic and glucose uptake modulator

Bacillus stercoris PSSR12 (B. stercoris PE), an isolate from rice field soils, was identified via 16s rRNA sequencing. The synthesis of the inulin and inulin producing enzyme (IPE) in B. stercoris PE was verified using SDS-PAGE and FTIR. This study aimed to assess the impact of B. stercoris PE treatment on in vitro inhibition of α-amylase and α-glucosidase from traditional and commercial rice varieties of South India. Additionally, the study investigated enzymatic inhibition and mRNA expression of starch synthesis genes (RAmy1a, GBSSIa, SBEIIa, and SBEIIb). Glucose transporter gene expression (GLUT1 and GLUT4) patterns were analyzed in 3T3-L1 adipocytes to evaluate glucose uptake in B. stercoris PE treated rice varieties. The application of B. stercoris PE enhanced grain quality by imparting starch ultra-structural rigidity, inhibiting starch metabolizing enzymes, and inducing molecular changes in starch synthesis genes. This approach holds promise for managing type II diabetes mellitus and potentially reducing insulin dependence.

Study on the gelatinization and digestive characteristics of wheat starch and potato starch under low moisture conditions

This study explored the gelatinization and digestive characteristics of wheat and potato starches under low moisture conditions using identical processing parameters. The results revealed that potato starch exhibited greater resistance to digestion than wheat starch, with an enzyme hydrolysis rate 18 % to 30 % lower than wheat starch under the same conditions. The analysis of particle size, swelling power, and low-field NMR demonstrated that potato starch required almost 40 % more moisture for full gelatinization than wheat starch, indicating that low-moisture conditions could not meet the significant water demand of potato starch. Additionally, the DSC analysis showed that potato starch had superior thermal stability, with To of 62.13 °C and ΔH of 16.30 (J/g). Subsequently, the microscopy results showed that the partially gelatinized wheat starch had a rough, porous surface, allowing enzymes for direct access to hydrolysis. In contrast, the potato starch had smoother and less damaged particles without visible pores, enzymes had to degrade it progressively, layer by layer. Furthermore, potato starch still exhibited a lower enzyme hydrolysis rate than wheat starch under the same gelatinization levels. Overall, potato starch is more resistant to hydrolysis and gelatinization in low-moisture environments, making potato starch suitable for low-digestibility products like potato biscuits or chips.

Functional Foods from Black Rice (Oryza sativa L.): An Overview of the Influence of Drying, Storage, and Processing on Bioactive Molecules and Health-Promoting Effects

Black rice (Oryza sativa) stands out for its high content of bioactive compounds with functional properties that play an important role in health benefits. The phytochemical level is affected by industrial processing due to its instability to the hydrothermal process. Studies about the influence of industrial processing on the phytochemical profile of black-rice-based foods are still scarce. This study carried out a comprehensive review of the influence of industrial applications on the bioactive compounds in food products based on black rice and their health-promoting effects. Most industrial processes such as drying, storage, cooking, and extrusion affect phytochemical content and antioxidant capacity. Alternatively, technologies such as fermentation, UV-C irradiation, and sprouting can maintain or improve the phytochemical content in black rice products.

The Potential of Crude and Partially Purified Black Rice Bran Extracts Obtained by Ultrasound-Assisted Extraction: Anti-Glycemic, Cytotoxicity, Cytoprotective, and Antitumoral Effects

Recovering anthocyanins from black rice bran is a way of valuing this byproduct, by obtaining an extract with biological potential. The objective of this study was to recover anthocyanins using ultrasound-assisted extraction. Some of the extract was partially purified, and both (crude and partially purified) extracts were evaluated for their anthocyanin content, antioxidant activity, antidiabetic and antitumoral activities, cytotoxicity, and oxidative stress. An increase in the laboratory scale was also achieved, making possible to increase the extraction volume up to 20 times without significantly changing the content of anthocyanins (1.85 mg C3G/g DW). It was found that the purified sample presented a 4.2 times higher value of total anthocyanins compared to the crude sample. The best IC50 values for the purified sample were verified by DPPH and ABTS (0.76 and 0.33 mg/mL). The best results for antidiabetic activity were obtained for the partially purified sample: 0.82 µM C3G for α-glucosidase and 12.5 µM C3G for α-amylase. The extracts demonstrated protection (~70%) when subjected to the oxidative stress of L929 cells. An antitumoral effect of 25-30% for both extracts was found in A459 cells. The crude and partially purified extracts of black rice have antidiabetic and anticancer effects and more studies are needed to explore their potential.

Metabolomics Reveals Antioxidant Metabolites in Colored Rice Grains

Colored rice is richer in nutrients and contains more nutrients and bioactive substances than ordinary white rice. Moderate consumption of black (purple) rice has a variety of physiological effects, such as antioxidant effects, blood lipid regulation, and blood sugar control. Therefore, we utilized nontargeted metabolomics, quantitative assays for flavonoid and phenolic compounds, and physiological and biochemical data to explore the correlations between metabolites and the development of antioxidant characteristics in pigmented rice seeds. The findings indicated that, among Yangjinnuo 818 (YJN818), Hongnuo (HN), Yangchannuo 1 hao (YCN1H), and Yangzi 6 hao (YZ6H), YZ6H exhibited the highest PAL activity, which was 2.13, 3.08, and 3.25 times greater than those of YJN818, HN, and YCN1H, respectively. YZ6H likewise exhibited the highest flavonoid content, which was 3.8, 7.06, and 35.54 times greater than those of YJN818, HN, and YCN1H, respectively. YZ6H also had the highest total antioxidant capacity, which was 2.42, 3.76, and 3.77 times greater than those of YJN818, HN, and YCN1H, respectively. Thus, purple rice grains have stronger antioxidant properties than other colored rice grains. Receiver operating characteristic (ROC) curve analysis revealed that trans-3,3',4',5,5',7-hexahydroxyflavanone, phorizin, and trilobatin in the YZ6H, HN, and YCN1H comparison groups all had area under the curve (AUC) values of 1. Phlorizin, trans-3,3',4',5,5',7-hexahydroxyflavanone, and trilobatin were recognized as indices of antioxidant capability in colored rice in this research. This research adds to the understanding of antioxidant compounds in pigmented rice, which can increase the nutritional value of rice and promote the overall well-being of individuals. This type of information is of immense importance in maintaining a balanced and healthy diet.

Whole Flour of Purple Maize as a Functional Ingredient of Gluten-Free Bread: Effect of In Vitro Digestion on Starch and Bioaccessibility of Bioactive Compounds

The growing demand for gluten-free products requires the study of alternatives to produce nutritionally and technologically favorable foods. The aim was to evaluate the content and antioxidant capacity of gluten-free bread enriched with whole flour of purple maize (PM) and how starch and bioaccessibility of antioxidant compounds were modified during in vitro digestion. Gluten-free bread was prepared with the addition of 34%, 50%, and 70% PM, and white maize bread served as control. The content of total polyphenols, anthocyanins, and antioxidant capacity through FRAP and TEAC was measured. Specific volume, crumb texture, and starch digestibility were determined in the breads. Simultaneously, in vitro digestion and dialysis by membrane were performed to evaluate the bioaccessible and potentially bioavailable fraction. Bread with 34% PM had a similar specific volume and crumb texture to the control, but higher content of polyphenols (52.91 mg AG/100 g), anthocyanins (23.13 mg c3-GE/100 g), and antioxidant capacity (3.55 and 5.12 µmol tr/g for FRAP and TEAC, respectively). The PM breads had a higher antioxidant content and capacity and higher slowly digestible and resistant starch than the control. These parameters increased as the PM proportion rose. After digestion, anthocyanins were degraded, polyphenols and antioxidant capacity decreased, but they remained potentially bioavailable, although to a lesser extent. Bread with 34% shows acceptable technological parameters, lower starch digestibility, and contribution of bioactive compounds with antioxidant capacity. This indicates that purple maize flour represents a potential ingredient to produce gluten-free bread with an improved nutritional profile.

Potential roles of cereal bioactive compounds in the prevention and treatment of type 2 diabetes: A review of the current knowledge

Diabetes is one of the most common non-communicable diseases in both developed and underdeveloped countries with a 9.3% prevalence. Unhealthy diets and sedentary lifestyles are among the most common reasons for type 2 diabetes mellitus (T2DM). Diet plays a crucial role in both the etiology and treatment of T2DM. There are several recommendations regarding the carbohydrate intake of patients with T2DM. One of them is about reducing the total carbohydrate intake and/or changing the type of carbohydrate to reduce the glycaemic index. Cereals are good sources of carbohydrates in the diet with a significant amount of soluble and non-soluble fiber content. Apart from fiber, it has been shown that the bioactive compounds present in cereals such as proteins, phenolic compounds, carotenoids, and tocols have beneficial impacts in the prevention and treatment of T2DM. Moreover, cereal by-products especially the by-products of milling processes, which are bran and germ, have been reported to have anti-diabetic activities mainly because of their fiber and polyphenols content. Considering the potential functions of cereals in patients with T2DM, this review focuses on the roles of cereal bioactive compounds in the prevention and treatment of type 2 diabetes.

Genome-Wide Identification, Evolution, and Expression Analysis of the WD40 Subfamily in Oryza Genus

The WD40 superfamily is widely found in eukaryotes and has essential subunits that serve as scaffolds for protein complexes. WD40 proteins play important regulatory roles in plant development and physiological processes, such as transcription regulation and signal transduction; it is also involved in anthocyanin biosynthesis. In rice, only OsTTG1 was found to be associated with anthocyanin biosynthesis, and evolutionary analysis of the WD40 gene family in multiple species is less studied. Here, a genome-wide analysis of the subfamily belonging to WD40-TTG1 was performed in nine AA genome species: Oryza sativa ssp. japonica, Oryza sativa ssp. indica, Oryza rufipogon, Oryza glaberrima, Oryza meridionalis, Oryza barthii, Oryza glumaepatula, Oryza nivara, and Oryza longistaminata. In this study, 383 WD40 genes in the Oryza genus were identified, and they were classified into four groups by phylogenetic analysis, with most members in group C and group D. They were found to be unevenly distributed across 12 chromosomes. A total of 39 collinear gene pairs were identified in the Oryza genus, and all were segmental duplications. WD40s had similar expansion patterns in the Oryza genus. Ka/Ks analyses indicated that they had undergone mainly purifying selection during evolution. Furthermore, WD40s in the Oryza genus have similar evolutionary patterns, so Oryza sativa ssp. indica was used as a model species for further analysis. The cis-acting elements analysis showed that many genes were related to jasmonic acid and light response. Among them, OsiWD40-26/37/42 contained elements of flavonoid synthesis, and OsiWD40-15 had MYB binding sites, indicating that they might be related to anthocyanin synthesis. The expression profile analysis at different stages revealed that most OsiWD40s were expressed in leaves, roots, and panicles. The expression of OsiWD40s was further analyzed by qRT-PCR in 9311 (indica) under various hormone treatments and abiotic stresses. OsiWD40-24 was found to be responsive to both phytohormones and abiotic stresses, suggesting that it might play an important role in plant stress resistance. And many OsiWD40s might be more involved in cold stress tolerance. These findings contribute to a better understanding of the evolution of the WD40 subfamily. The analyzed candidate genes can be used for the exploration of practical applications in rice, such as cultivar culture for colored rice, stress tolerance varieties, and morphological marker development.

Effect of processing methods and storage on the bioactive compounds of black rice (Oryza sativa L.): a review

Compared to brown and white rice, black rice contains more nutrients and numerous unique bioactive substances, such as essential amino acids, dietary fiber, γ-oryzanols, γ-aminobutyric acid, phenolic compounds, and anthocyanins, which makes it highly valuable for development and use. Whole-grain black rice typically requires a certain amount of processing prior to consumption, with the primary goal of enhancing the taste and texture of whole grains and their products. However, various new processing technologies have been effectively applied to the processing of black rice and the enhancement of its qualitative characteristics, but they also have both positive and negative effects on its nutritional quality. Therefore, evaluation of changes in concentrations of the bioactive substances as natural antioxidants due to processing and storage conditions is critical for establishing dietary guidelines for rice. This review highlights the primary bioactive components of black rice and provides a discussion of the impact of processing methods and storage on the bioactive components of black rice. Furthermore, we summarized the issues that currently exist in the processing and storage of black rice.

Insights into Recent Updates on Factors and Technologies That Modulate the Glycemic Index of Rice and Its Products

Rice is a staple food and energy source for half the world's population. Due to its quick digestion and absorption in the gastrointestinal tract, rice is typically regarded as having a high or medium-high glycemic index (GI); however, this can vary depending on the variety, nutrient compositions, processing, and accompanying factors. This report included a table of the glycemic index for rice and rice products in different countries, which could give an overview and fundamental information on the recent GI of different rice varieties. In addition, latest updates about the mechanism effects of rice nutritional profiles and processing techniques on GI were also provided and discussed. The influence of state-of-the-art GI regulation methods was also evaluated. Furthermore, the effectiveness and efficiency of applied technologies were also given. Furthermore, this review offered some aspects about the potential nutraceutical application of rice that food scientists, producers, or consumers might consider. Diverse types of rice are grown under various conditions that could affect the GI of the product. The instinct nutrients in rice could show different effects on the digestion rate of its product. It also revealed that the rice product's digestibility is process-dependent. The postprandial glucose response of the rice products could be changed by modifying processing techniques, which might produce the new less-digestive compound or the inhibition factor in the starch hydrolysis process. Because of the significant importance of rice, this paper also concluded the challenges, as well as some important aspects for future research.

The effects of Moringa peregrina seed meal, autoclaving, and/or exogenous enzyme cocktail on performance, carcass traits, meat quality, and blood lipids of broilers

The effects of Moringa peregrina seed meal (MPSM), autoclaving, and/or enzyme cocktail addition on performance, profitability, carcass traits, meat quality, and blood lipids of broilers between 1 and 35 d of age were investigated. Seven experimental diets were employed: the control 0% MPSM, 10% raw MPSM, 10% autoclaved MPSM (at a temperature of 120°C and 1 kg/cm² pressure for 30 min), 10% raw MPSM supplemented with enzymes at 0.1 or 0.2 g/kg feed, and 10% autoclaved MPSM supplemented with the same previous enzymes and doses. Each diet was fed to 8 replicates with 5 broilers in each. At the end of the experiment, 3 broilers from each replicate were randomLy chosen to determine carcass traits, meat quality, and blood lipids. Findings at 35 d of age indicated that all 10% raw MPSM treatments with or without enzymes addition impaired growth, feed conversion (FCR), and profitability (p < 0.05), but increased feed intake (p < 0.05) and did not affect mortality when compared with the control group. The 10% autoclaved MPSM treatments with or without enzymes addition increased feed intake (p < 0.05) when compared with the control group, inducing growth equal to the control group (p > 0.05), and improving FCR and profitability. Enzymes addition to raw MPSM did not produce positive effects (p < 0.05), and no additive effect was observed when autoclaving and enzymes addition were combined (p > 0.05) as compared to the autoclaving group. Carcass traits, meat quality, and blood lipids were not significantly affected by MPSM, autoclaving, and enzymes addition. However, intestine, cecum, and gizzard percentages increased (p < 0.05) with all 10% raw MPSM treatments, while all 10% autoclaved MPSM treatments could return these values (p > 0.05) to the control group, except with gizzard, which exhibited less improvement. Additionally, all autoclaved groups had lower meat pH measured 24 h postmortem (p <0.05) compared to the control group. In conclusion, autoclaved MPSM can be included in broilers' diets at a 10% level without negative effects on performance, carcass traits, meat quality, and blood lipids. This indicates that autoclaving alone is adequate.

The Glycemic Index of Indica and Japonica Subspecies Parboiled Rice Grown in Italy and the Effect on Glycemic Index of Different Parboiling Processes

Rice is generally considered a high-glycemic index (GI) food, but numerous studies show that parboiling reduces the GI. There are no studies on GI of Indica and Japonica subspecies parboiled rice grown in Italy. The aim of this study was (1) to evaluate GI in different varieties of parboiled rice (ribe, white and brown long B, basmati, black, red, roma, and arborio); (2) to evaluate GI of same variety of rice subjected to different rice parboiling processes (parboiled ribe and parboiled long B with two different methods: flora and conventional method); (3) to evaluate GI of two by-products of parboiled rice: white and brown rice cake. Participants were 10 healthy individuals (20-30 years old, body mass index 18.5-25 kg/m²). Proximate composition and GI were determined by using standard methods. All parboiled rice assessed is low-GI (brown long B 48.1 ± 6.4 by flora method, ribe 52.0 ± 1.8 GI by flora method, black rice 52.3 ± 7.6 by flora method, long B 52.4 ± 3.9 by flora method, long B 53.4 ± 5.1 by conventional method, ribe 54.4 ± 4.3 GI by conventional method, Roma 54.4 ± 7.9 GI by flora method, and arborio 54.4 ± 7.9 GI by flora method), except red rice that is of medium-GI (56.1 ± 7.0 GI), and both classic and brown cakes that are high-GI (respectively, 83.3 ± 8.9 GI and 102.2 ± 5.5 GI). Parboiled rice is low-GI and so is favorable for the dietary management of metabolic disorders and celiac disease. Clinicaltrials.gov (NCT05333081).

Complexing curcumin and resveratrol in the starch crystalline network alters in vitro starch digestion: Towards developing healthy food materials

Starch is an abundant and common food ingredient capable of complexing with various bioactive compounds (BCs), including polyphenols. However, little information is available about using native starch network arrangement for the starch-BCs inclusion. Herein, two BCs, curcumin, and resveratrol, were undertaken to delineate the role of different starch crystalline types on their encapsulation efficiency. Four starches with different crystalline types, botanical sources, and amylose content were examined. The results suggest that B-type hexagonal packing is necessary to encapsulate curcumin and resveratrol successfully. The increase in XRD crystallinity while maintaining the FTIR band at 1048/1016 cm^-1 suggests that BCs are likely entrapped inside the starch granule than attaching to the granule surface. A significant change in starch digestion is seen only for the B-starch complexes. Embedding BCs in the starch network and controlling starch digestion could be a cost-effective and valuable approach to designing and developing novel starch-based functional food ingredients.

Ultrasonic-assisted immersion of parboiled treatment improves head rice yield and nutrition of black rice and provides a softer texture of cooked black rice

Parboiling is gaining increasing attention as it can enhance the head rice yield (HRY) and nutritional quality of non-pigmented rice. The traditional parboiling process with high-temperature immersion requires a long immersion period and results in hard texture of cooked parboiled black rice (PBR), which may be addressed by ultrasound-assisted immersion. In this study, we evaluated the effect of power, time and temperature of ultrasonic immersion on the HRY, texture profile and nutritional quality of PBR. Proper ultrasound-assisted immersion could increase the HRY by about 20% and the GABA content by up to 133%, as well as reduce the arsenic and cadmium content by up to 61% and 79% relative to untreated black rice (UBR), respectively. Moreover, it could increase the content of essential minerals such as calcium, iron and zinc to some extent, and free and bound polyphenols, despite of a certain loss of anthocyanins. It could also improve the palatability of cooked rice. Furthermore, response surface experiments based on the Box-Behnken design were performed to obtain and validate the optimal conditions of ultrasound-assisted immersion (540 W, 45 min, 57 °C). On this basis, morphological changes might be one reason for the improved HRY, nutrition and texture of PBR compared with those of UBR, namely the disappearance of cracks near the aleurone layer and formation of new cracks in the interior of rice.

Factors influencing the starch digestibility of starchy foods: A review

Starchy foods are a major energy source of the human diet, their digestion is closely related to human health. Most foods require lots of processing before eating, therefore, many factors can influence starch digestibility. The factors that affect the digestibility of starches have been widely discussed previously, but the extracted starches in those studies were different from those present within the actual food matrix. This review summarizes the factors influencing the starch digestibility in starchy foods. Endogenous non-starch components hinder the starch digestive process. Food ingredients and additives decrease starch digestibility by inhibiting the activity of digestive enzymes or hindering the contact between starch and enzymes. Storage induce the retrogradation of starch, decreasing the digestibility of foods. Therefore, preparing starchy foods with whole grains, processing them as little as possible, using food additives reasonably, and storage conditions may all be beneficial measures for the production of low GI foods.

Food safety assessments of acrylamide formation and characterizations of flaky rolls enriched with black rice (Oryza sativa)

This study aims to investigate the physicochemical composition, textural parameters, and chemical constituent of flaky rolls incorporated with different proportions of black rice flour. According to farinographic characteristics, the addition of black rice flour could reduce the stability and increase the dough development time and water absorption (%). While for the extensographic properties, addition of black rice flour resulted in significantly different maximum resistance to extension (BU) and extensibility (cm) vs. the control. With the addition of black rice flour in flaky rolls, the crude protein, total dietary fiber (TDF), soluble dietary fiber (SDF), and insoluble dietary fiber (IDF) were significantly improved. Glucose released was much lower with 10 and 20% black rice than the control and 5% black rice because of the higher black rice inclusion. With increasing black rice incorporation, total anthocyanin content, and antioxidant capacity was also improved. The content of asparagine, acrylamide, hydroxymethylfurfural (HMF), furfural, methylglyoxal, and glyoxal in flaky rolls was also increased. The proper content of black rice flour (5%) could significantly enhance the stability of the dough properties; control the final volume, texture, and appearance; and retain good protein and fiber composition, antioxidant capacity, and overall acceptance of the flaky roll.

The Effect of Soybean Peptides on Improving Quality and the ACE Inhibitory Bioactivity of Extruded Rice

It is crucial to address the dietary problems of hypertensive patients. The effect and mechanism of different contents of soybean protein on cooking quality and angiotensin-converting enzyme (ACE) inhibitory action in the extruded rice were firstly investigated. The results showed that the extruded rice with soybean protein possessed the higher taste value (90.32 ± 2.31), hardness (2.65 ± 0.01 g), and good pasting quality (p ≤ 0.05). Meanwhile, the soybean protein notably retarded the starch digestibility; the sample with 6% soybean protein showed the fewest rapidly digestible starch (RDS) content (78.82 ± 0.01 mg g−1) and the most slowly digestible starch (SDS) content (8.97 ± 0.45 mg g−1). Importantly, the ACE inhibition rate improved from 17.09 ± 0.01% to 74.02 ± 0.65% in the 6% soybean protein sample because of the production of peptides. The peptide composition of samples were compared, which showed that the effective ACE-inhibitory peptides usually contain 2~20 amino acids, and Pro, Leu, Ile, Val, Phe, and Ala were the main components. Overall, moderate soybean protein would give a good quality and lower ACE activity in extruded food.

Dietary proanthocyanidins on gastrointestinal health and the interactions with gut microbiota

Many epidemiological and experimental studies have consistently reported the beneficial effects of dietary proanthocyanidins (PAC) on improving gastrointestinal physiological functions. This review aims to present a comprehensive perspective by focusing on structural properties, interactions and gastrointestinal protection of PAC. In brief, the main findings of this review are summarized as follows: (1) Structural features are critical factors in determining the bioavailability and subsequent pharmacology of PAC; (2) PAC and/or their bacterial metabolites can play a direct role in the gastrointestinal tract through their antioxidant, antibacterial, anti-inflammatory, and anti-proliferative properties; (3) PAC can reduce the digestion, absorption, and bioavailability of carbohydrates, proteins, and lipids by interacting with them or their according enzymes and transporters in the gastrointestinal tract; (4). PAC showed a prebiotic-like effect by interacting with the microflora in the intestinal tract, and the enhancement of PAC on a variety of probiotics, such as Bifidobacterium spp. and Lactobacillus spp. could be associated with potential benefits to human health. In conclusion, the potential effects of PAC in prevention and alleviation of gastrointestinal diseases are remarkable but clinical evidence is urgently needed.

The nutritional profile and human health benefit of pigmented rice and the impact of post-harvest processes and product development on the nutritional components: A review

Pigmented rice has attracted considerable attention due to its nutritional value, which is in large conferred by its abundant content of phenolic compounds, considerable micronutrient concentrations, as well as its higher resistant starch and thereby slower digestibility properties. A wide range of phenolic compounds identified in pigmented rice exhibit biological activities such as antioxidant activity, anti-inflammatory, anticancer, and antidiabetic properties. Post-harvest processes significantly reduce the levels of these phytochemicals, but recent developments in processing methods have allowed greater retention of their contents. Pigmented rice has also been converted to different products for food preservation and to derive functional foods. Profiling a large set of pigmented rice cultivars will thus not only provide new insights into the phytochemical diversity of rice and the genes underlying the vast array of secondary metabolites present in this species but also provide information concerning their nutritional benefits, which will be instrumental in breeding healthier rice. The present review mainly focuses on the nutritional composition of pigmented rice and how it can impact human health alongside the effects of post-harvest processes and product development methods to retain the ambient level of phytochemicals in the final processed form in which it is consumed.

Nutritional Properties of Rice Varieties Commonly Consumed in Italy and Applicability in Gluten Free Diet

Gluten-free diets are often characterized by an inadequate intake of nutrients and are generally monotonous for the limited number of products celiac patients can use. As rice is the most used cereal by celiac consumers, studying rice varieties nutritional characteristics is of interest to manage diet quality and variety. Proteins, total carbohydrates and amylose content of six rice varieties (Ribe, Vialone Nano, Carnaroli, Arborio, Basmati, and Fragrance) were analyzed. Analyses were performed in raw products and after boiling, stewing, and microwaving. A decrease of proteins and total carbohydrates amount was observed in cooked rice. The same was reported for amylose content with boiling showing the highest loss (average retained amylose 53%). Considering amylose percentage with respect to total carbohydrates, each variety showed either an increase or a decrease depending on cooking method. The highest values were obtained with stewing above all for Basmati rice and Arborio rice. However, exceptions can be underlined as Carnaroli rice, showing the highest percentage when boiled. In this context, nutritional characteristics of cooked rice varieties appear to be of great importance to increase specific nutritional knowledge to better manage gluten-free diets.