Effects of Binding between Ca in Hard Water and Phosphorus in Amylopectin on the Qualities of Boiled Rice and Rice Noodle Prepared by Soaking and Boiling in Hard Water.

Recently, global warming has led to an increase in chalky rice grains. This has consequently resulted in the deterioration in quality of rice products. Although we previously reported that hard water, rich in Ca, is useful for the quality improvement of high-temperature-damaged rice grains, the mechanism was not elucidated sufficiently.

Effects of Hard Water Boiling on Chalky Rice in Terms of Texture Improvement and Ca Fortification.

In the present paper, we investigated the characteristics of chalky rice grains generated by ripening under high temperature and compared them with whole grains. We evaluated 14 unpolished rice grains harvested in Japan in 2021, and these samples (original grains) were divided into two groups (a whole grain group and a chalky grain one). We found that not only activities of endogenous amylase and proteinase, but also cell wall-degrading enzymes, such as xylanase and cellulase, changed markedly between chalky grains and whole grains.

Palatability and Bio-Functionality of Chalky Grains Generated by High-Temperature Ripening and Development of Formulae for Estimating the Degree of Damage Using a Rapid Visco Analyzer of Unpolished Rice.

Global warming inhibits grain filling in rice and leads to chalky grains, which are damaged in physical and cooking qualities. In the present paper, we evaluated 54 unpolished rice grains harvested in Japan in 2020, and these samples (original grains) were divided to two groups (whole grains and chalky grains). Using rice grains of 100% whole grains or those blended with 30% of chalky grains, we measured contents of sugars and amino acids, and textural properties of boiled rice grains.

Black rice bran intake reduces phosphorylated tau levels and enhances insulin signaling in the brain of aged normal mice.

This study reports that black rice bran (BRB) intake for 50-52 consecutive weeks (∼12 months) reduces tau phosphorylation with a concomitant activation of insulin signaling and subsequent PI3K/AKT pathway in the brain of aged normal mice. BRB holds promise for preventing the formation of neurofibrillary tangles consisting of hyperphosphorylated tau, a pathological hallmark of Alzheimer's disease.

Effect of heat-moisture treated brown rice crackers on postprandial flow-mediated dilation in adults with mild endothelial dysfunction.

Background: Endothelial dysfunction is an early pathophysiological feature and independent predictor of a poor prognosis in most forms of cardiovascular disease. We evaluated the effect of brown rice crackers (BR-C) on endothelial function.

Methods: Effect of heat-moisture treated (HMT) -BR-C on postprandial flow-mediated dilation (FMD) in adults with mild endothelial dysfunction was compared with that of BR-C and white rice crackers (WR-C) in 12 adults with mild endothelial dysfunction (less than 7.

Editorial for the Special Issue, "Quality Assay, Processing and Bio-Function of Rice Products".

Rice is one of the most important cereals in the world alongside wheat and maize [...

Possibility for Prevention of Type 2 Diabetes Mellitus and Dementia Using Three Kinds of Brown Rice Blends after High-Pressure Treatment.

As it has been reported that type 2 diabetes mellitus increases the risk of Alzheimer’s disease, we investigated how to prevent type 2 diabetes and dementia using biofunctional boiled rice. We adopted unpolished super-hard rice (SHBR) for diabetes and wax-free unpolished black rice (WFBBR) for dementia and blended those with ordinary non-polished rice (KBR) (blending ratio 4:4:2), adding 2.5% waxy black rice bran (WBB) and 0.

Characteristics of Physicochemical Properties of Chalky Grains of Rice Generated by High Temperature during Ripening.

Global warming has caused devastating damage to starch biosynthesis, which has led to the increase in chalky grains of rice. This study was conducted to characterize the qualities of chalky rice grains and to develop the estimation formulae for their quality damage degree. We evaluated the chalkiness of 40 rice samples harvested in 2019, in Japan.

Low-Protein Diet: History and Use of Processed Low-Protein Rice for the Treatment of Chronic Kidney Disease.

The epidemiology of chronic kidney disease (CKD) shows increasing trends in prevalence and mortality and has become the leading health problem worldwide. Reducing the amount of proteins ingested from rice is an easy way to control the total intake of proteins, saving energy sources, particularly in rice-eating countries. In Japan, low-protein white rice had been developed, but the taste and function were not satisfactory for CKD patients.

Evaluation of Hardness and Retrogradation of Cooked Rice Based on Its Pasting Properties Using a Novel RVA Testing.

With rice being one of the most important crops worldwide, rapid and objective quality evaluation methods based on physicochemical measurements of rice are necessary. We compared the pasting properties of various rice samples using three different heating and cooling programs (maximum temperatures were 93, 120, and 140 °C, respectively) in a newly developed high-temperature-type Rapid Visco Analyzer (RVA , RVA 4800). Furthermore, we investigated the relationship between the different pasting properties measured by the three programs, with starch microstructure measured by iodine scanning analysis, the physical properties of the cooked rice measured by a Tensipresser after 2 h at 25 °C or after 24 h at 6 °C, and prolamin ratio measured by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).

Development of a novel formula for estimating the amylose content of starch using japonica milled rice flours based on the iodine absorption curve.

The apparent amylose content (AAC) is usually measured by an iodine colorimetric method using the starch as a sample. Nevertheless, it is time-consuming and labor-intensive to prepare rice starch. Therefore, we compared two methods, starch method and milled rice flour method.

Physicochemical measurements of Japonica rice cultivars in Heilongjiang Province.

We here characterized 27 japonica rice cultivars grown in Heilongjiang province and evaluated the relationship among their iodine absorption curve, physical properties, and ratio of 13 kDa prolamin. We developed the novel estimation formulae for ratio of 13 kDa prolamin and overall hardness (H2) with the use of A and λmax.

Development and characterization of a new rice cultivar, 'Chikushi-kona 85', derived from a starch-branching enzyme IIb-deficient mutant line.

A new super-hard rice cultivar, 'Chikushi-kona 85', which was derived from a cross between 'Fukei 2032' and 'EM129', was developed via bulk method breeding. 'Chikushi-kona 85' showed a higher content of resistant starch than the normal non-glutinous rice cultivar, 'Nishihomare', and a higher grain yield than the first super-hard rice cultivar, 'EM10'. The amylopectin chain length of 'Chikushi-kona 85' and its progenitor line 'EM129' was longer than that of 'Nishihomare', and was similar to that of 'EM10'.

Effects of different heat-moisture treatments on the physicochemical properties of brown rice flour.

We evaluated the effect of heat-moisture treatment (HMT) on the main chemical components, physical properties, and enzyme activities of two types of brown rice flour: high-amylose Koshinokaori and normal-quality Koshiibuki. Five different HMTs using brown rice (moisture content was 12.0%) were assessed: 0.

Effects of super-hard rice bread blended with black rice bran on amyloid β peptide production and abrupt increase in postprandial blood glucose levels in mice.

Alzheimer's disease and type 2 diabetes are very serious diseases with the latter having been suggested to cause the former. We prepared super-hard rice bread blended with black rice bran (SRBBB), which contained a high amount of resistant starch that showed strong inhibitory activities against β-secretase and acetylcholinesterase even after heating. Black rice bran showed greater β-secretase inhibitory activity (3.

Comparison of eating quality and physicochemical properties between Japanese and Chinese rice cultivars.

In this study, we evaluated 16 Japanese and Chinese rice cultivars in terms of their main chemical components, iodine absorption curve, apparent amylose content (AAC), pasting property, resistant starch content, physical properties, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, and enzyme activity. Based on these quality evaluations, we concluded that Chinese rice varieties are characterized by a high protein and the grain texture after cooking has high hardness and low stickiness. In a previous study, we developed a novel formula for estimating AAC based on the iodine absorption curve.

An inverting β-1,2-mannosidase belonging to glycoside hydrolase family 130 from Dyadobacter fermentans.

The glycoside hydrolase family (GH) 130 is composed of inverting phosphorylases that catalyze reversible phosphorolysis of β-D-mannosides. Here we report a glycoside hydrolase as a new member of GH130. Dfer_3176 from Dyadobacter fermentans showed no synthetic activity using α-D-mannose 1-phosphate but it released α-D-mannose from β-1,2-mannooligosaccharides with an inversion of the anomeric configuration, indicating that Dfer_3176 is a β-1,2-mannosidase.

Development of formulae for estimating amylose content and resistant starch content based on the pasting properties measured by RVA of Japonica polished rice and starch.

We searched for the easy and simple method to measure the novel indicators which reflect not only AAC, but also (RS) based on pasting properties using RVA. Novel indexes such as SB/Con and Max/Fin (Maximum viscosity/Minimum viscosity) ratios had a very high correlation with proportion of intermediate and long chains of amylopectin; Fb1+2+3 (DP ≧ 13). In Japonica polished rice, estimation formulae for AAC and RS content were developed using novel indexes based on pasting properties by RVA, and these equations showed determination coefficients of 0.

Measurement of resistant starch content in cooked rice and analysis of gelatinization and retrogradation characteristics.

Digestion-resistant starch (RS) has many physiologic functions. The RS content is measured by enzymatically degrading flour samples according to the method of the Association of Official Analytical Chemists. Experiments have been performed with wheat, corn, and other grains, but there are no data for cooked rice grains in the form ingested by humans.

Discovery of two β-1,2-mannoside phosphorylases showing different chain-length specificities from Thermoanaerobacter sp. X-514.

We characterized Teth514_1788 and Teth514_1789, belonging to glycoside hydrolase family 130, from Thermoanaerobacter sp. X-514. These two enzymes catalyzed the synthesis of 1,2-β-oligomannan using β-1,2-mannobiose and d-mannose as the optimal acceptors, respectively, in the presence of the donor α-d-mannose 1-phosphate.

Development of formulae for estimating amylose content, amylopectin chain length distribution, and resistant starch content based on the iodine absorption curve of rice starch.

Not only amylose but also amylopectin greatly affects the gelatinization properties of rice starch and the quality of cooked rice grains. We here characterized the starches of 32 rice cultivars and evaluated the relationship between their iodine absorption curve, apparent amylose content (AAC), pasting property, resistant starch (RS) content, and chain length distribution of amylopectin. We found that the iodine absorption curve differed among the various sample rice cultivars.

2-O-α-D-glucosylglycerol phosphorylase from Bacillus selenitireducens MLS10 possessing hydrolytic activity on β-D-glucose 1-phosphate.

The glycoside hydrolase family (GH) 65 is a family of inverting phosphorylases that act on α-glucosides. A GH65 protein (Bsel_2816) from Bacillus selenitireducens MLS10 exhibited inorganic phosphate (Pi)-dependent hydrolysis of kojibiose at the rate of 0.43 s(-1).

Improved palatability and bio-functionality of super-hard rice by soaking in a barley-koji miso suspension.

Cooked grains of ae rice cultivars are too hard and non-sticky due to the presence of long-chain amylopectin, and ae rice cultivars are therefore called ``super-hard rice'' and cannot be used as table rice. However, they are promising in terms of their bio-functionality such as preventing diabetes. Miso (soybean paste) is a yeast-fermented food, made from steamed soybeans, salt, and inoculated cereals known as koji, made from rice, barley, or soybeans.

Discovery of cellobionic acid phosphorylase in cellulolytic bacteria and fungi.

A novel phosphorylase was characterized as new member of glycoside hydrolase family 94 from the cellulolytic bacterium Xanthomonas campestris and the fungus Neurospora crassa. The enzyme catalyzed reversible phosphorolysis of cellobionic acid. We propose 4-O-β-D-glucopyranosyl-D-gluconic acid: phosphate α-D-glucosyltransferase as the systematic name and cellobionic acid phosphorylase as the short names for the novel enzyme.