Average Temperature during the Ripening Period to Obtain First Grade Rice and High Enzymatic Digestibility of Steamed Rice of Brewer’s Rice Cultivar ‘Ginnoyume’ in Kochi Prefecture

Effect of weak alkaline electrolyzed water on rice cooking: Promoting rapid water absorption and enhancing the quality and digestibility

Protein Quality of Conventional and High Protein Rice and Digestibility of Glutinous and Non-Glutinous Rice by Preschool Children

Effects of cooking, retrogradation and drying on starch digestibility in instant rice making

Rice is one of the most consumed staple foods around the world and its trade is highly globalized. Increased environmental pollution generates a large amount of waste that, in many cases, is discarded close to culture fields. Some species are able to bioaccumulate toxic substances, such as metals, that could be transferred to the food chain. The main goal of this study was to evaluate the content of metallic (Al, Cd, Pb, and Cr) and metalloid elements (As) in 14 of the most consumed varieties of rice in Spain and their effects on human health. The samples were cooked, and human digestion was simulated by using a standard in vitro digestion method. Metallic and metalloid element levels were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), previous called microwave digestion. Both the human health risk index, Hazard Quotient, and Lifetime Cancer Risk did not show toxic values in any case. Rice with a higher non-digestible fraction showed a higher liberation of proteins and a lower glycemic index. There were no significant differences in the concentrations of metallic and metalloid elements in cooked rice or in the digestible fraction in all varieties analysed. However, Al concentrations were higher than other metals in all varieties studied due to its global distribution. No relationship has been observed between the digestibility of rice and the bioaccessibility of each metallic and metalloid element. All of the studied rice varieties are healthy food products and its daily consumption is safe. The regular monitoring of metals and As in rice consumed in Spain may contribute to improvements in the human health risk evaluation.

Improving benefits and reducing risk of staple food consumption are of interest among researchers nowadays. Rice is the major staple foods consumed in Asia. It has been reported that rice consumption has a positive association with the risk of chronic diseases. The effects of rice variety and preparation process on chemical characteristics of rice were investigated in the current study. Three Thai rice varieties, Khao Dok Mali 105 (KDML 105), Sao Hai (SH) and Riceberry (RB), underwent parboiling or non-parboiling as well as polishing or non-polishing prior to chemical property analysis. It was found that parboiling process possessed greater content of mineral as indicated by ash content as well as fiber and total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity when compared to non-parboiling treatments, whereas the reduction in amylose and TAC content, GI value and starch digestibility were observed in this sample. On the other hand, polishing process led to reduction in ash, amylose, fiber, TPC and TAC content and DPPH values. GI value and starch digestibility of non-parboiled rice were lowest in SH, RB and KDML 105, respectively. However, with parboiling treatment, GI values among rice varieties were not significantly different. It can be concluded that natural composition of each rice variety is different and it affects human health. However, preparation process can alter the chemical property of rice as well as influence health benefit of rice.

2016～2020年の5年間に高知県の11地域で生産された酒米品種「吟の夢」の玄米とその栽培履歴を用いて，「吟の夢」玄米品質の地域間，年次間差の実態やその発生要因を検討した．地域間では，千粒重，整粒割合，心白発現率，検査等級，アルカリ崩壊性において有意な差が認められ，整粒割合，心白発現率，検査等級，アルカリ崩壊性では変動係数が10以上と比較的大きかった．年次間では，千粒重，整粒割合，蛋白質含有率，アルカリ崩壊性において有意な差が認められ，整粒割合，アルカリ崩壊性では変動係数が10以上であった．地域間，年次間ともに有意差が認められた玄米品質形質の最大値と最小値の差は，地域間，年次間それぞれにおいて，千粒重では1.5 g，1.2 g，整粒割合では32.5％，15.4％，アルカリ崩壊性では0.49，0.24であった．同様に，変動係数は，千粒重では1.9，2.2，整粒割合では14.5，10.1，アルカリ崩壊性では19.7，11.7であった．よって，千粒重は地域間差，年次間差が同程度，整粒割合，アルカリ崩壊性は年次間差より地域間差が大きいと判断された．また，地域間では，整粒割合は標高と正，登熟期間の平均気温および日射量と負，心白発現率は登熟期間の日射量と正，成熟期と負，検査等級は登熟期間の平均気温および日射量と正，標高と負，アルカリ崩壊性は標高，成熟期と正，登熟期間の平均気温および日射量と負の有意な相関関係を示した．以上より，「吟の夢」玄米品質の高位平準化に向けて，整粒割合，心白発現率，検査等級，アルカリ崩壊性の地域間差を小さくすることが第一に重要であると考えられた．また，整粒割合，心白発現率，検査等級，アルカリ崩壊性の地域間差には，標高や成熟期を介して登熟期間の平均気温や日射量が影響していることが推察されたため，各生産地域における適正な登熟期間の気象条件となる栽培法を提示する必要がある．

Comparison among the Rice Cultivars with New Demand in Relation to Dry Matter Production and Adaptability to Early-Season Culture in Kochi Prefecture

Regional and Yearly Variation of Brown Rice Quality, and Their Factors in Brewer’s Rice Cultivar ‘Ginnoyume’ in Kochi Prefecture.

Introgression of Green Revolution sd1 gene into isogenic genome of rice super cultivar Koshihikari to create novel semidwarf cultivar ‘Hikarishinseiki’ (Koshihikari-sd1)

High yield and high grain quality cultivation method for multipurpose use rice varieties in Kochi Prefecture

Multi-scale structural insights on starch digestibility of instant rice

This study employed four rice varieties differing in amylose content: japonica rice A (JRA), japonica rice B (JRB), indica rice (IR), and glutinous rice (GR). Using tap water as the control, the impact of weak alkaline electrolyzed water (WAEW) on the gel formation and digestibility of rice was investigated. Results indicated that WAEW significantly enhanced the texture properties and gel strength of cooked rice. WAEW promoted starch hydrolysis during cooking, leading to increases in amylose content and soluble sugars. WAEW further broke down the ordered structure of starch granules during cooking, resulting in a denser network structure in the cooked rice. Except for in vitro digestibility, WAEW showed consistent effects on all four rice varieties. For JRA, JRB, and IR, WAEW treatment increased rapidly digestible starch and slowly digestible starch levels but reduced resistant starch levels. However, GR showed lower rapidly digestible starch and higher slowly digestible starch after WAEW treatment. This study clarified the effect of WAEW on cooked rice gel formation, offering potential industrial insights for enhancing the quality and nutritional value of cooked rice.

Microstructure of indica and japonica rice influences their starch digestibility: A study using a human digestion simulator

Temperature is a primary factor that affects the rate of plant development and has great impacts on plant growth, metabolism, and yield. A study was conducted to analyze the effects of elevated temperature on rice morphological and the physiological growth. The research was arranged in a nested randomized block design consisting of two factors, temperatures and rice varieties. Elevated temperatures were provided through the uses of different materials of plastic roof and walls to have an average and maximum temperature of 27.6 °C and 41.6 °C (T1); 28.1°C and 43.8 °C (T2), and 29.5°C and 47.1 C (T3), respectively. The study used three varieties of rice, “Ciasem”, “Ciherang”, and “IR64”. All rice varieties showed signifi cant increases in tiller number per hill and shoot dry weight, but had a decrease in the stomatal conductance, transpiration rate, and SPAD values at grain fi lling stage with the increasing temperatures. The number of tiller per hill increased when temperature was elevated from 27.6 to 28.1 and 29.5°C by about 29.9 and 21.3%, respectively.

16 rice varieties (Oryza sativa L.) were evaluated for their tolerance to heat stress up to 8 weeks after planting. The rice varieties consisted of drought tolerance rice varieties, black rice varieties, low-land varieties, and commercial varieties. The experiment was arranged using a split plot design with temperature as a main plot and a rice variety/accession as a sub plot with three replications. The treatment for high temperature consisted of actual temperature in the screenhouse (N1), the temperature above 38oC (N2), and above 40oC (N3) at mid-day. The average temperature and humidity for N1, N2, and N3 at noon was 36.4oC and 67%, 38.9oC and 60%, and 41.6oC and 45%, respectively. The result showed that heat stress affected plant height, tiller number per plant, leaf number per plant, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, and root number per plant. There was also significant difference between the tested varieties on plant height, tiller number, leaf number, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, and root number per plant. The interaction between high temperature and variety was significant on plant height, tiller number, leaf number, root fresh weight, and root dry weight. Jaliteng and Situbagendit had the highest tiller number and leaf number under N3 condition (above 40oC at the mid-day).