Effects of parboiling and infrared radiation drying on the quality of germinated brown rice

This research investigated the physicochemical properties, bioactive compounds, and microstructure of brown rice (BR) and non-parboiled and parboiled germinated brown rice (GBR and PGBR). The GBR and PGBR were treated by sun, hot-air oven, or infrared irradiation (IR) drying. The results showed that IR drying enhanced the bioactive compounds of non-parboiled GBR, including γ-aminobutyric acid, α-tocopherol, and total phenolic compounds, while γ-oryzanol and antioxidant activity were comparable to BR. Meanwhile, IR drying significantly improved the head rice yield (HRY) of PGBR while reducing fissured grains. Parboiling also affected the color values of rice grains, suggesting the diffusion of husk color into endosperm and the formation of brown polymers by the Maillard reaction. In addition, IR drying altered the internal structure of rice grains, resulting in abundant intercellular voids. Specifically, the IR-dried non-parboiled GBR significantly enhanced essential bioactive compounds and improved HRY while maintaining the color of standard BR.     

Effects of parboiling and fluidized bed drying on the physicochemical properties of germinated brown rice

Changes in physicochemical properties of germinated brown rice (GBR) and parboiled germinated brown rice (PGBR) dried in a fluidized bed dryer at 110–150 °C were investigated. Results indicated that parboiling altered the properties of GBR owing to starch gelatinisation. The moisture content, yellowness, peak viscosity and hardness of PGBR increased, but internal fissured kernel, cooking time, water absorption and total solids loss decreased when compared to GBR. γ‐aminobutyric acid (GABA) content in GBR was 23.31 mg per 100 g and was reduced to 17.91 mg per 100 g in PGBR. The drying times required to reduce the moisture content of GBR and PGBR to 16% d.b. were 4.01–7.65 min and 5.11–9.50 min, respectively. Final moisture content, which is optimum to prevent internal fissures of dried GBR and PGBR, was 27–29% and 25–28% d.b., respectively. The same trend was observed in the physicochemical properties of GBR and PGBR when increasing drying temperature and time.     

Effect of pre‐germination time of brown rice on serum cholesterol levels of hypercholesterolaemic rats

BACKGROUND: Brown rice is unpolished rice with immeasurable benefits for human health. Brown rice (BR) and pre‐germinated brown rice (PGBR) are known to contain various functional compounds such as γ‐oryzanol, dietary fibre and γ‐aminobutyric acid (GABA). In the present study, the experimental diets containing BR and PGBR (24, 48 h pre‐germination) were used to investigate the influence of pre‐germination time of brown rice on blood cholesterol in Sprague–Dawley male rats. RESULTS: Hypercholesterolaemia and elevation of LDL‐cholesterol were successfully ameliorated by the experimental diets containing BR and PGBR (24 and 48 h pre‐germination). As compared to the control sample, the pre‐germination time had a significant (P < 0.05) effect on blood cholesterol of Sprague–Dawley male rats. It was also found that the significantly (P < 0.05) better effect on lipid profile of hypercholesterolaemic rats was observed by prolonging the pre‐germination time. As compared to non‐germinated brown rice, the germinated brown rice showed the higher cardio‐protective effect on hypercholesterolaemic Sprague–Dawley male rats. CONCLUSION: The present study suggests that the changes of blood cholesterol can be mainly modulated by using the PGBR rather than BR. The prolonging of pre‐germination time led to an increase in the bioactive components, thereby providing a more efficient functional diet affecting the high blood cholesterol. This study suggests that PGBR can be used instead of BR and polished rice in the human diet. Copyright © 2009 Society of Chemical Industry     

Brown Rice Versus White Rice: Nutritional Quality,Potential Health Benefits,Development of Food Products,and Preservation Technologies

Obesity and chronic diet‐related diseases such as type 2 diabetes, hypertension, cardiovascular disease, cancers, and celiac are increasing worldwide. The increasing prevalence of these diseases has led nutritionists and food scientists to pay more attention to the relationship between diet and different disease risks. Among different foods, rice has received increasing attention because it is a major component of billions of peoples’ diets throughout the world. Rice is commonly consumed after polishing or whitening and the polished grain is known a high glycemic food because of its high starch content. In addition, the removal of the outer bran layer during rice milling results in a loss of nutrients, dietary fiber, and bioactive components. Therefore, many studies were performed to investigate the potential health benefits for the consumption of whole brown rice (BR) grain in comparison to the milled or white rice (WR). The objective of this work was to review the recent advances in research performed for purposes of evaluation of nutritional value and potential health benefits of the whole BR grain. Studies carried out for purposes of developing BR‐based food products are reviewed. BR safety and preservation treatments are also explored. In addition, economic and environmental benefits for the consumption of whole BR instead of the polished or WR are presented. Furthermore, challenges facing the commercialization of BR and future perspectives to promote its utilization as food are discussed.     

Germination Conditions Affect Physicochemical Properties of Germinated Brown Rice Flour

ABSTRACT:  Germinated brown rice has been reported to be nutritious due to increased free gamma-aminobutyric acid (GABA). The physicochemical properties of brown rice (BR) and glutinous brown rice (GNBR) after germination as affected by different steeping times (24, 36, 48, and 72 h depending on the rice variety) and pHs of steeping water (3, 5, 7, and as-is) were determined and compared to those of the nongerminated one (control). As the steeping time increased or pH of steeping water decreased, germinated brown rice flours (GBRF) from both BR and GNBR had greater reducing sugar, free GABA and α-amylase activity; while the total starch and viscosity were lower than their respective controls. GBRFs from both BR and GNBR prepared after 24-h steeping time at pH 3 contained a high content of free GABA at 32.70 and 30.69 mg/100 g flour, respectively. The peak viscosity of GBRF obtained from both BR and GNBR (7.42 to 228.22 and 4.42 to 58.67 RVU, respectively) was significantly lower than that of their controls (255.46 and 190.17 RVU, respectively). The principal component analysis indicated that the important variables for discriminating among GBRFs, explained by the first 2 components at 89.82% of total explained variance, were the pasting profiles, α-amylase activity, and free GABA.     

Quantitative microbiological profiles of brown rice and germinated brown rice

Among health conscious people, brown rice (BR) and germinated brown rice (GBR) are increasingly more popular for consumption in Korea because their nutritional values are greater than those of ordinary white rice (WR). The overall microbial counts for BR were higher than those for WR and those of GBR were higher than those of BR. Interestingly, the lactic acid bacteria (LAB) counts in GBR increased markedly and their selected representatives were Weissella confusa, Pediococcus pentosaceus, and Lactobacillus fermentum. To our knowledge, this is the first attempt to enumerate and compare LAB loads on WR, BR, and GBR.     

Effects of germination time on the structural,physicochemical and functional properties of brown rice

Germinated brown rice (GBR) is a gluten-free food raw material. Its tissue structure, physicochemical properties and functional properties depend on the germination time. In this study, rapid viscosity analyses, differential scanning calorimetry and X-ray diffraction et al were used to analyse the structural, physicochemical and functional changes in brown rice (BR) during germination. Gamma-aminobutyric acid (GABA), total phenolic compound, glutathione (GSH) and amino acid contents increased during germination. GBR exhibited the highest GSH (22.70 mg per 100 g) and amino acid (8.02 mg per 100 g) contents at 24 h and the highest GABA content (253.35 mg per 100 g) at 36 h. Furthermore, BR germinated for 36 h showed greater enthalpy (ΔH) than ungerminated BR. Although GBR showed less crystallinity than ungerminated BR, germination did not change the crystalline structure type of starch (A-type). These results inform choices of the appropriate applications of GBR to promote its utilisation in the food industry.     

干法、半干法和湿法磨粉对糙米粉性质的影响

研究干法、半干法及湿法3种磨粉方式对糙米粉损伤淀粉含量、平均粒径、微观结构、水合特性、热焓特性和流变性质等的影响。结果表明,干法磨粉糙米粉损伤淀粉含量、吸水指数、水溶性和膨胀势显著高于湿法和半干法。但干法磨粉糙米粉平均粒径、凝胶最大弹性模量和最大黏性模量显著小于湿法和半干法。干法和半干法糙米粉糊化焓值低于湿法。干法磨粉糙米粉形成了许多不规则的颗粒碎片,而半干法和湿法的糙米粉淀粉颗粒较完整。磨粉方式和条件显著影响糙米粉的性质,应根据糙米制品品质的要求选择合适的磨粉方式和磨粉条件。     

高RS_4含量大米的制备及初步食味品质评价

抗性淀粉由于其时健康的潜在益处以及独特的功能特性而受到了研究人员的广泛关注.以籼米为生产原料,乙酸乙烯酯为酯化剂进行乙酰化改性,在保持大米颗粒完整性的同时,使其中的淀粉分子发生醋酸酯化反应,产生抗消化性,从而制备出高Rs4含量的大米,以期能够作为开发糖尿病人主食或加工米制品的原料.通过冷冻等物理及化学的前处理方法强化传质,提高渗透速率和反应效率,确定了制备高RS4含量大米的最佳工艺.结果表明,最佳工艺为反应温度30℃,pH 10,液料比2:10(ml:g),反应时间5 h,此时抗性淀粉质量分数为78.740k,乙酰基质量分数为3.07%.抗性淀粉含量与乙酰基含量相关性分析表明二者之间没有相关性,因此实际生产中可在最佳工艺基础上选择更加环保、温和、经济的工艺条件.采用快速黏度分析仪(RVA)测定糊化特性,结合胶稠度和直链淀粉含量的测定,初步评价其食味品质.     

Antioxidant activity of white rice,brown rice and germinated brown rice (in vivo and in vitro) and the effects on lipid peroxidation and liver enzymes in hyperlipidaemic rabbits

Antioxidant activity of different rice extract and the effect on the levels of antioxidant enzyme activity, superoxide dismutase (SOD) and glutathione peroxidase (GPx), vitamin E, lipid peroxidation and liver enzymes in hyperlipidaemia rabbits were investigated. Germinated brown rice (GBR) has the highest antioxidant activity compared to white rice (WR) and brown rice (BR). All rice grains increased the activity of SOD and GPx. However, vitamin E levels increased only in the groups that received the BR and GBR diets. The reduction of lipid peroxidation levels and activity of hepatic enzymes (alanine transferase, ALT and aspartate transaminase, AST) were only significantly observed in the GBR group. In conclusion, GBR supplementation has the greatest impact on increasing antioxidant enzyme activity and vitamin E level and on reducing lipid peroxidation in hypercholesterolaemia rabbit, thereby preventing the formation of atherosclerotic plaques. Furthermore, GBR diet can also reduce the level of hepatic enzymes.     

Pre-Germinated Brown Rice Substituted Bread: Dough Characteristics and Bread Structure

Pre-germinated brown rice (PGBR) having the germ length of 0.5–1.0 mm is produced as a healthy food by immersing the brown rice in water. In this article, various additives were used for making PGBR breads, and suitable combinations of PGBR and additives for breadmaking were evaluated to provide PGBR bread with high functional properties. The 30% of the wheat flour was substituted with PGBR (PGBR 30), and combined additions of phytase (PHY), hemicellulase (HEM) and sucrose fatty acid ester (SE) to PGBR 30 improved the bread qualities with more suitable dough properties, as compared with the sample without their addition. During fermentation, the amounts of gas leaked from the PGBR 30 dough were suppressed by the additions. PHY and HEM hydrolyzed the phytate and hemicellulose in PGBR, and the maturity and extensibility of the PGBR 30 dough were caused by the activated yeast with formed phosphate and decomposed bran, making the large loaf volume and softness of breadcrumbs during storage. In addition, SE accelerated the dough tolerance to mixing or fermentation with the emulsifying ability. Therefore, the combined additions with PHY, HEM, and SE to PGBR 30 improved the dough and bread qualities.     

挤压预糊化淀粉的性能及其添加对糙米发糕品质的影响

通过挤压不同水分含量（45%、25%和18%）的大米淀粉制备预糊化大米淀粉,测定其分子量、结晶度、糊化度、水吸收指数、水溶解指数、冷糊黏度等指标,并考察了预糊化淀粉添加对糙米粉糊化特性及糙米发糕品质的影响。结果表明,与原大米淀粉相比,45%、25%和18%水分含量挤压制备的预糊化大米淀粉结晶度分别降低了51.93%、58.93%和59.04%;水吸收指数分别提高了1.56、4.69和6.11倍;水溶解指数分别提高了7.04、16.30和27.64倍;冷糊黏度分别提高了2.00、21.44和14.67倍。挤压还使大米淀粉分子发生降解,产生了更多的小链分子。预糊化大米淀粉性能变化与挤压过程中淀粉的水分含量有关。添加预糊化大米淀粉显著提高了糙米发糕的品质（P<0.05）,高的冷糊黏度和低的分子量（18%水分挤压）更有利于制备比容大（1.64 cm3/g）、孔洞细腻均匀、硬度低（338.59 g）和有弹性的糙米发糕。     

干法、半干法和湿法磨粉工艺制备的糙米米线品质研究

采用干法、半干法和湿法3种方式将糙米磨粉制备糙米米线,干法粉碎强度10～40 Hz,半干法调节含水量为20%～35%及湿法料液比为1∶1、1∶2、1∶3、1∶4,研究了3种磨粉方式对糙米米线蒸煮品质和质构性质的影响,并分析了糙米磨粉颗粒细度及损伤淀粉含量与糙米米线蒸煮品质的相关性。结果表明,磨粉方式及磨粉工艺条件显著影响糙米米线的蒸煮、质构和感官品质,糙米磨粉颗粒细度与糙米米线最佳蒸煮时间显著正相关,与糙米米线断条率显著负相关。糙米磨粉损伤淀粉含量与糙米米线最佳蒸煮时间、硬度显著负相关,损伤淀粉含量与糙米米线断条率显著正相关。干法粉碎强度10、半干法水分调节含量20%、30%和35%、湿法粉碎料液比1∶3～1∶4时,糙米米线的品质较好。     

Effect of High Pressure Treatment and Degree of Milling on Gelatinization and Structural Properties of Brown Rice

Brown rice (BR), medium-milled rice (MR), and fully milled white rice (WR), with different degrees of milling (DOM), 0, 6.6, and 10.4 %, respectively, were high pressure (HP) treated at 200 to 500 MPa for 5 to 15 min. Water absorption, swelling, and gelatinization properties, and microstructural changes were investigated. HP treatment (≥200 MPa) or partial milling (DOM 6.6 %) resulted in water absorption comparable with that of white rice. Swelling behavior was affected by milling and processing temperature. Both HP treatment and milling promoted gelatinization properties. In addition, partial milling reduced the pressure resistance of rice grain, while differences in water absorption, swelling behavior, and gelatinization properties due to milling were reduced by HP treatment. Further, the degree of gelatinization (DG) increased with HP treatment with 400 MPa and 10 min defined as the threshold values for pressure and holding time, respectively. DG values, observed with 400 MPa-10 min treatments, were 41.2, 50.2, and 39.9 %, respectively for BR, MR, and WR. Results demonstrated that HP treatment, combined with milling, is technically feasible and produces rice and rice flour with enhanced DG and swelling behavior. These basic data can be used to improve the processing efficiency and quality of brown rice-based product.     

Resistant Starch Content and Structural Changes in Maize (Zea mays) Tortillas During Storage

Storage of maize products such as tortillas may cause starch retrogradation and lead to resistant starch (RS) formation. This study was carried out to determine if storage of maize tortillas under refrigerated conditions enhanced RS content and/or modified RS structure. Improved Costeño variety maize grain was nixtamalized and processed into tortillas which were stored for five and ten days at 5°C. Total resistant starch (TRS) and retrograded resistant starch (RRS or RS3) contents were determined on raw and nixtamalized maize grain and tortillas stored for zero, five and ten days. Differential scanning calorimetry (DSC), X‐ray diffraction (XRD) and near‐infrared (NIR) spectroscopy were use to evaluate structural changes in retrograded resistant starch isolated from each sample type. Total starch content was 67 ± 1.5% for all samples, TRS ranged from 3.3% in the raw grain at 7.2% in tortillas stored for ten days, while RRS starch content ranged from 0% in the raw grain to 3.2% in tortillas stored for ten days. DSC showed endothermic transitions corresponding to amylopectin and amylose retrogradation, at 31.9 and 139.7°C in RRS from tortillas stored for five days, and at 47.9 and 146°C in RRS from tortillas stored for ten days. These values agreed with the higher total RS content recorded after prolonged storage. XRD revealed a starch crystallinity of 13.7% in tortillas stored for five days and 15.3% in those stored for ten days. NIR spectroscopy analysis showed evidence of structural changes in polymeric order that were more pronounced in RRS of tortillas stored for ten days, due to increase in crystalline region.     

Functional Properties as Affected by Laboratory‐Scale Parboiling of Rough Rice and Brown Rice

ABSTRACT: Rough rice (RR) is the conventional feedstock for parboiling. The use of brown rice (BR) instead of RR is gaining interest because it results in shorter processing time and lower energy requirement. This study compared the functional properties of milled parboiled rice under different parboiling conditions from RR and BR. Presoaked RR and BR from cultivars Bolivar, Cheniere, Dixiebelle, and Wells were parboiled under mild (20 min, 100 °C, 0 kPa) and severe (20 min, 120 °C, 98 kPa) laboratory‐scale conditions. Head rice yield improved on the RR and BR samples subjected to severe parboiling and was comparable to that of a commercially parboiled sample. Mild parboiling of BR resulted in lower head rice yields. Parboiling generally resulted in decreased head rice whiteness, decreased apparent amylose, increased total lipid, and sparingly changed protein content. Under the same parboiling conditions, the extent of starch gelatinization was higher for BR compared to RR as manifested by some distinct differences in pasting and thermal properties. The cooking characteristics (water uptake ratio, leached materials, and volumetric expansion) and cooked rice texture (hardness and stickiness) of RR and BR subjected to severe parboiling were fairly comparable. Differences in parboiled rice functional properties due to cultivar effect were evident.     

不同品种糙米营养品质和理化特性比较

以7个来源于湖北省的不同品种糙米为原料,以营养组分含量、阳离子交换能力、胆固醇吸附能力、亚硝酸根吸附能力、淀粉消化特性为评价指标,研究比较糙米品种间营养品质和理化特性的差异性,旨在为糙米加工原料选择提供参考。结果表明：不同品种糙米的粗蛋白、直链淀粉、氨基酸和总酚含量差异较大,广两优香66的粗蛋白和必需氨基酸含量均最高,而罗田贡米的直链淀粉和总酚含量最高,分别为15.90%（m/m）和196.54 mg GAE/100 g DW。罗田贡米的胆固醇吸附能力和亚硝酸根吸附能力分别为 55.05 mg/g和0.20 mg/g,均显著高于其它品种糙米（P<0.05）,广两优香66和鄂中5号也展现出较强的阳离子交换能力和亚硝酸根吸附能力;巨两优60和罗田贡米的快速消化淀粉含量最低,慢速消化淀粉含量最高,具有明显延缓淀粉消化的作用。比较筛选出广两优香66（高蛋白、高赖氨酸）和罗田贡米（高总酚、胆固醇和亚硝酸根吸附能力强、延缓淀粉消化作用强）的高营养和高功能性质的品种。该研究为糙米加工及产品开发提供了数据支撑。     

2018—2020年广东省河粉类食品米酵菌酸中毒事件流行病学分析

目的 分析广东省河粉类食品相关米酵菌酸中毒的流行病学特征,为米酵菌酸中毒的预防控制提供科学依据。方法 采用描述流行病学方法,对广东省河粉类食品相关米酵菌酸中毒事件进行分析。结果 2018—2020年广东省共报告5起因食用河粉类食品引起的米酵菌酸中毒事件,中毒21人,死亡9人,病死率为42.9%;临床特征出现较多的症状是呕吐、腹泻、腹痛;主要发生在第三、四季度。广东省5起米酵菌酸中毒事件涉事食品均为食品加工厂批量生产的湿淀粉制品或湿大米制品,且发现涉事河粉存在异于传统的特点：添加了较大量的淀粉;使用了脱氢乙酸钠;在常温下保存超过24 h,但并没有明显的腐败变质。结论 该5起河粉类食品中毒事件是罕见的由加工食品引起的米酵菌酸中毒,需要进一步分析该类食品生产经营过程的薄弱环节、提出针对性的控制措施,同时加强消费提示和食品安全知识宣教,引导生产经营者、消费者合理保存食品,并在保质期内销售和食用。     

Biological activity of rice extract and the inhibition potential of rice extract,rice volatile compounds and their combination against α-glucosidase, α-amylase and tyrosinase

Rice is produced for consumption and traditional medicine. Rice is also used as an ingredient in cosmetic products. In this study, the author investigated the biological activity and inhibition potential against α-glucosidase, α-amylase and tyrosinase activity of rice extract (black rice [BR], red rice [RR] and white rice [WR]), rice volatile compounds, rice extract combined with volatile compounds, rice extract combined with standard inhibitors and volatile compounds combined with standard inhibitors. The results revealed that the free-radical scavenging capacity of rice extract is related to the phenolic content and flavonoids. BR showed the highest potential to inhibit α-glucosidase and α-amylase activity, whereas WR showed the highest potential to inhibit tyrosinase activity. Among rice volatile compounds, vanillin and vanillyl alcohol had the highest inhibition potential against α-glucosidase and α-amylase, respectively, whereas guaiacol had the highest inhibitory activity against tyrosinase. Molecular docking supported by the high binding efficiency was also obtained from vanillin and guaiacol when located at the active site of these enzymes. The combination of RR with acarbose (AB) had the highest inhibition potential and showed a synergic effect on both α-glucosidase and α-amylase. Interestingly, the combination of rice extract (BR, RR and WR) and vanillin and vanillyl alcohol had a synergic effect on α-amylase. Moreover, the combination of WR and vanillyl alcohol had the highest inhibition potential and showed a synergic effect on tyrosinase, whereas rice volatile compounds had a synergic effect on tyrosinase obtained from 2-pentylfuran/kojic acid (KA), vanillin/KA and vanillyl alcohol/KA.     

以短生育期籼稻为原料的鲜湿米粉食用品质与消化特性研究

以早、晚季种植的短生育期籼米品种(CPPC16、CPPC18、CPPC38、CPPC52)为对象,对大米淀粉物化特性进行比较;并对8种短生育期大米加工的鲜湿米粉的食用品质和消化特性进行探究。结果表明：早季稻与晚季稻相比较,早季稻的直链淀粉含量、回生值与糊化温度高于同品种的晚季稻。大米淀粉特性与鲜湿米粉质构特性相关性分析中,直链淀粉含量、回生值与最终黏度、水溶性与质构指标呈显著(P<0.05)或极显著正相关(P<0.01),膨胀力与质构指标呈显著负相关(P<0.05)。对比两种鲜湿米粉加工专用米种,短生育期品种中以早季18号的综合评分最高(0.93),略低于桂朝米的1.07,高于阳春米的0.87。