Minerals in vitro bioaccessibility and changes in textural and structural characteristics of uncooked pre-germinated brown rice influenced by ultra-high pressure

The impact of milling degree on physicochemical, nutritional, rheological, textural properties, and in vitro digestibility of rice: From brown rice to white rice

The objective of this study was to characterize the rice milling fractions acquired at each stage of a commercial milling system. This characterization included an analysis of color, ash content, dietary fiber, mineral composition, as well as antinutritional compounds like phytic acid, trypsin inhibitor activity, and saponin. Additionally, we investigated in vitro starch and in vitro protein digestibility, along with pasting, cooking, and textural properties. Our findings revealed that milling improved the visual appeal of rice (e.g., volume expansion, weight gain, whiteness) and notably enhanced its starch digestibility. However, milling reduced dietary fiber, mineral content, antinutrients, cooking time, and texture characteristics such as hardness, chewiness, gumminess, springiness, and cohesiveness to varying degrees. Certain parameters, such as dietary fiber, exhibited a gradual change with the duration of milling, while others, such as mineral content and texture, showed significant variation at the initial stage of milling, particularly at the first mill.

Prolonging heat-moisture treatment time at medium moisture content optimizes the quality attributes of cooked brown rice through starch structural alteration

Brown rice (BR), one of the popular whole grains worldwide, is still limited to consumption due to its rough texture after cooking. Through inspecting structural alteration, this work discloses how heat-moisture treatment (HMT) moisture content (15 %-25 %) and time (1.0 h-3.0 h) modify the starch digestibility and cooked BR texture. The medium moisture content (20 %) allowed the highest pasting viscosity and a uniform network structure of cooked BR. Prolonging the HMT time from 1.0 h to 2.0 h at medium moisture content hindered starch swelling and improved stability. Meanwhile, the relative crystallinity, the surface compactness in nanoscale and R995/1022 decreased, while the gel network structure was improved, contributing to the softened cooked BR texture and the enhanced starch digestibility. Although the resistant starch content raised to 13.55 % after 3.0 h of HMT, the springiness, gumminess and chewiness of cooked BR degraded, and this should be considered in certain conditions.

Effect of milling on in vitro Digestion-Induced release and bioaccessibility of active compounds in rice

To investigate the impact of milling on the active components in rice, this study examined the stability of phenols, vitamin B1 (VB1), and alpha-aminobutyric acid (α-GABA) during cooking and digestion of rice and their distribution in digestive juices and residue by adjusting the degree of milling (DOM). The findings revealed that milling exacerbated the instability of γ-GABA during cooking and VB1 during digestion. Their total losses peaked at 19.76% and 39.53% as DOM respectively reached 6.07% and 8.06%. In vitro digestion combined with release mathematical models demonstrated the impact of milling on their bioaccessibility. This effect increased the small intestinal bioaccessibility of phenols and γ-GABA, whilst reducing that of VB1. This was attributed to milling-induced pre-gastric full release of VB1, which amplifies its intestinal susceptibility and induces its re-entry into digestive residues. In conclusion, this study recommends keeping DOM below 6.07% to optimize the bioaccessibility of these active compounds.

Nitrogen fertilizer affects the cooking quality and starch properties of proso millet (Panicum miliaceum L.)

Nitrogen has a critical influence on the yield and quality of proso millet. However, the exact impact of nitrogen on the cooking quality of proso millet is not clear. In this study, the cooking quality and starch properties of two proso millet varieties (waxy-Shaanxi millet [wSM] variety and non-waxy-Shaanxi millet [nSM] variety) were compared and analyzed under nitrogen fertilizer treatment (N150, 150 kg/hm2) and a control group without nitrogen application (N0, 0 kg/hm2). Compared with the N0 group, the N150 treatment significantly increased protein content, amylose levels, and total yield. Employing rapid visco analyser and differential scanning calorimetry analyses, we observed that under the N150 treatment, the peak viscosity and breakdown viscosity of proso millet powder were diminished, while the setback viscosity and enthalpy values (ΔH) increased. In addition, nitrogen treatment increased the solids content in the obtained rice soup and significantly hardened the texture of the rice. At the same time, we noticed that the absorption capacity of starch in water and oil was enhanced. These results showed that nitrogen fertilizer had significant effects on the cooking quality and starch properties of proso millet.

Metabolomics and machine learning technique revealed that germination enhances the multi-nutritional properties of pigmented rice

Enhancing the dietary properties of rice is crucial to contribute to alleviating hidden hunger and non-communicable diseases in rice-consuming countries. Germination is a bioprocessing approach to increase the bioavailability of nutrients in rice. However, there is a scarce information on how germination impacts the overall nutritional profile of pigmented rice sprouts (PRS). Herein, we demonstrated that germination resulted to increase levels of certain dietary compounds, such as free phenolics and micronutrients (Ca, Na, Fe, Zn, riboflavin, and biotin). Metabolomic analysis revealed the preferential accumulation of dipeptides, GABA, and flavonoids in the germination process. Genome-wide association studies of the PRS suggested the activation of specific genes such as CHS1 and UGT genes responsible for increasing certain flavonoid compounds. Haplotype analyses showed a significant difference (P < 0.05) between alleles associated with these genes. Genetic markers associated with these flavonoids were incorporated into the random forest model, improving the accuracy of prediction of multi-nutritional properties from 89.7% to 97.7%. Deploying this knowledge to breed rice with multi-nutritional properties will be timely to address double burden nutritional challenges.

Comparison of high-pressure, freeze-thaw cycles and germination-parboiling treatments on lipids digestibility and rancidity of brown rice

Brown rice (BR) contains more lipids, as compared with white rice, but its indigestibility and rancidity limit the consumer acceptability. Therefore, the objective of this study was to compare the effect of high-pressure (HP), freeze–thaw cycles (FTC) and germination-parboiling (GP) treatments on lipid in vitro digestibility and rancidity of BR. GP treated BR released the most fatty acids (especially palmitic acid and stearic acid) after in vitro digestion, followed by FTC treated BR. FTC treated BR kept the highest value of fat acidity during storage, while opposite results were observed in GP treated BR. Although HP treatment increased fat acidity value immediately, it slowed down the increase of fat acidity with storage. The results of conjugated dienes and malonaldehydes content in BR stored under accelerated conditions indicated better lipid oxidation stability after HP and GP treatment, and that it’s necessary for FTC treated BR products to be stored under anaerobic conditions.

Effect of high hydrostatic pressure on the edible quality, health and safety attributes of plant-based foods represented by cereals and legumes: a review

Consumers today are increasingly willing to reduce their meat consumption and adopt plant-based alternatives in their diet. As a main source of plant-based foods, cereals and legumes (CLs) together could make up for all the essential nutrients that humans consume daily. However, the consumption of CLs and their derivatives is facing many challenges, such as the poor palatability of coarse grains and vegetarian meat, the presence of anti-nutritional factors, and allergenic proteins in CLs, and the vulnerability of plant-based foods to microbial contamination. Recently, high hydrostatic pressure (HHP) technology has been used to tailor the techno-functionality of plant proteins and induce cold gelatinization of starch in CLs to improve the edible quality of plant-based products. The nutritional value (e.g., the bioavailability of vitamins and minerals, reduction of anti-nutritional factors of legume proteins) and bio-functional properties (e.g., production of bioactive peptides, increasing the content of γ-aminobutyric acid) of CLs were significantly improved as affected by HHP. Moreover, the food safety of plant-based products could be significantly improved as well. HHP lowered the risk of microbial contamination through the inactivation of numerous microorganisms, spores, and enzymes in CLs and alleviated the allergy symptoms from consumption of plant-based foods.

Effect of high pressure processing on the microstructure, myofibrillar protein oxidation, and volatile compounds of sauce lamb tripe

In this study, sauce lamb tripe was used as the research object. High pressure processing (HPP) was carried out at 100, 250, and 400 MPa, with holding times of 5, 10, 15, 20, and 25 min at 25 °C, respectively. The effects of HPP on the microstructure and volatile compound content of sauce lamb tripe and the properties of myofibrillar protein were studied. The degree of protein oxidation was most significant at 400 MPa for 25 min. The secondary structure of myofibrillar protein became unstable and the microstructure of the sauce lamb tripe became loose at 400 MPa. The retention of hydrocarbons, aldehydes, alcohols, and ketones was maximum at 250 MPa for 15 min, and the flavor-contributing compound (3-Hydroxy-2-butanone) was also retained by 11.9% on ketones at 250 MPa for 15 min. The results showed that myofibrillar protein was appropriately oxidized; the sauce lamb tripe had better microstructure and several representative volatile compounds after HPP. Therefore, better processing conditions for sauce lamb tripe were 250 MPa for 15 min.

Texture Modification Technologies and Their Opportunities for the Production of Dysphagia Foods: A Review

Dysphagia or swallowing difficulty is a common morbidity experienced by those who have suffered a stroke or those undergone such treatments as head and neck surgeries. Dysphagic patients require special foods that are easier to swallow. Various technologies, including high-pressure processing, high-hydrodynamic pressure processing, pulsed electric field treatment, plasma processing, ultrasound-assisted processing, and irradiation have been applied to modify food texture to make it more suitable for such patients. This review surveys the applications of these technologies for food texture modification of products made of meat, rice, starch, and carbohydrates, as well as fruits and vegetables. The review also attempts to categorize, via the use of such key characteristics as hardness and viscosity, texture-modified foods into various dysphagia diet levels. Current and future trends of dysphagia food production, including the use of three-dimensional food printing to reduce the design and fabrication time, to enhance the sensory characteristics, as well as to create visually attractive foods, are also mentioned.

Innovative processing techniques for altering the physicochemical properties of wholegrain brown rice (Oryza sativa L.) - opportunities for enhancing food quality and health attributes

Rice is a globally important staple consumed by billions of people, and recently there has been considerable interest in promoting the consumption of wholegrain brown rice (WBR) due to its obvious advantages over polished rice in metabolically protective activities. This work highlights the effects of innovative processing technologies on the quality and functional properties of WBR in comparison with traditional approaches; and it is aimed at establishing a quantitative and/or qualitative link between physicochemical changes and high-efficient processing methods. Compared with thermal treatments, applications of innovative nonthermal techniques, such as high hydrostatic pressure (HHP), pulsed electric fields (PEF), ultrasound and cold plasma, are not limited to modifying physicochemical properties of WBR grains, since improvements in nutritional and functional components as well as a reduction in anti-nutritional factors can also be achieved through inducing related biochemical transformation. Much information about processing methods and parameters which influence WBR quality changes has been obtained, but simultaneously achieving the product stabilization and functionality of processed WBR grains requires a comprehensive evaluation of all the quality changes induced by different processing procedures as well as quantitative insights into the relationship between the changes and processing variables.

Mild high hydrostatic pressure pretreatments applied before soaking process to modulate wholegrain brown rice germination: An examination on embryo growth and physicochemical properties

This investigation aimed to examine the effects of a novel processing pattern, combining high hydrostatic pressure (HHP) with germination, on the embryo growth and physicochemical characteristics of wholegrain brown rice (WBR). WBR grains were firstly subjected to mild HHP stress (30-90 MPa/5 min) and then incubated at 37 °C for 52 h for obtaining germinated samples (GBR). The results showed that HHP shock resulted in a delayed embryo growth of WBR grains, maintaining acceptable sprouting rates ranging from 65% to 76% when germination was finished. The contents of gama-aminobutyric acid in GBR were greatly increased responding to HHP stress, showing pressure intensities dependent. Total digestible and resistant starch contents in samples stressed at 60/90 MPa were decreased, mainly associated with high pressure-induced amorphization as revealed by SEM imaging and FTIR, which promoted starch hydrolysis during germination. Besides, the levels of zinc and iron were influenced by HHP pretreatments due to the high pressure-mediated degradation behavior for phytic acids. The storability of HHP-stressed GBR grains was significantly enhanced through reducing free fatty acids formation and maintaining color stability during a storage testing. These results obtained from the current work demonstrated that mild HHP stress pretreatment prior to germination process could be used as a promising strategy to modulate certain physicochemical characteristics of WBR products.

Comparison of physicochemical properties and cooking edibility of waxy and non-waxy proso millet (Panicum miliaceum L.)

The quality characteristics of waxy and non-waxy proso millet (Panicum miliaceum L.) are different because of their varying amylose content. Physical appearance, pasting properties, cooking and edibility were investigated in five waxy and five non-waxy proso millet varieties. The results showed that the amylose content of proso millet flour was positively correlated with peak viscosity, trough viscosity, breakdown viscosity, final viscosity, setback viscosity, peak time, and pasting temperature. The porridge made with non-waxy proso millet was thicker as compared with that of made with waxy proso millet. Cooked non-waxy proso millet was hard whereas waxy proso millet was sticky. The non-waxy proso millet contained higher resistant starch and lower rapidly digestible starch than waxy proso millet. From this study, we can conclude that quality characteristics of waxy and non-waxy proso millet are different, and this may provide an insight in food processing and commercial production of proso millet.

Bioaccessibility of calcium, iron and magnesium in residues of citrus and characterization of macronutrients

The aim of this study was to estimate bioaccessibility of Ca, Fe and Mg in residues of orange, lime, and their mixture, in order to evaluate the effects of cooking in water on mineral bioaccessibility and also to determine the composition of macronutrients and myo-inositol phosphate content. The citrus samples contained on average 9.53g/100 g moisture, 6.09g/100 g protein, 3.23g/100g ash, 3.15g/100g lipids, 34.26g/100g insoluble fiber, 27.88g/100g soluble fiber and 25.64g/100g carbohydrates. The percentage of soluble and dialyzable minerals ranged from 19.36 to 77.33% and from 5.59 to 69.06% for Fe, from 33.34 to 60.84% and 14.71 to -26.13% for Ca, and from 29.95 to 94.20% and 34.42 to 62.51%, for Mg, respectively. It was verified that cooking influenced the minerals bioaccessibility and increased the dialyzable fraction of Fe and Mg, but decreased the fraction of Ca dialysate, except to orange. No myoinositol phosphate esters were detected. The Principal Component Analysis allowed the separation of different types of citrus residues, but did not discriminate the raw and cooked samples. This study pointed the potential of citrus residue to be used for human consumption and contribute to the necessary dietary minerals and macronutrients, with high content of soluble and insoluble fibers.