Factor analysis of the functional properties of rice flours from mutant genotypes

A set of 27 waxy rice genotypes and 52 rice genotypes with medium and high amylose contents were screened for various functional properties of flour. In this study, 68 genotypes containing various amylose contents (1.2–30.4%) were mutants of the rice variety TNG67 widely grown in Taiwan. The proximate composition, pasting, thermal and textural properties of rice flours were determined and analysed with factor analysis to assess the genetic differences. A wide variation in various functional properties was observed. Factor analysis indicated that four factors relating to amylose content, gel textural, gelatinization and protein content could explain 80% of the variability among 79 rice flours. Correlation studies and scatter diagrams also indicated the larger role of amylose with respect to protein and lipid in determining the rice flour quality. The present study can be used for readily identifying differences between rice genotypes for eating/cooking quality.     

Physicochemical Properties of Starch and Flour from Different Rice Cultivars

The starches and flours from four different rice cultivars were evaluated for composition, crystallinity characteristics, blue value, turbidity, swelling power, solubility, pasting properties, and textural and retrogradation properties. The amylose content of starches and flours from different rice cultivars differed significantly. The results showed that the physicochemical properties of rice starch and rice flour were correlated to amylose content. The crystallinity degree of rice starch and flour depended on amylose content. The blue value, turbidity value, and gel hardness were positively correlated to amylose content; however, the swelling power, solubility, and gel adhesiveness were negatively correlated to amylose content. Furthermore, the pasting properties and gel textural and retrogradation properties of rice flours were related to the structure properties of rice starch. And the characteristics of starch, protein, and lipid significantly influenced the turbidity, pasting properties, and gel textural and retrogradation properties of rice flours.     

复配粉理化性质与米线质构性质关系的研究

将粳米粉与绿豆淀粉按照一定比例进行混合,得到粳米粉和绿豆淀粉的复配粉体系,并测定了复配粉体系的溶胀性质、糊化性质、凝胶质构性质和拉伸性质,研究了复配米粉体系的拉伸性质与米线质构性质的关系。结果表明:随着绿豆淀粉添加量比例的增加,复配米粉体系的总直链淀粉含量、可溶性直链淀粉含量和不溶性直链淀粉含量明显增加,峰值黏度、谷值黏度、末值黏度、硬度也显著性增加,咀嚼性、拉伸强度和表观弹性模量显著增加,85℃下的溶解度和膨润力显著上升;糊化温度显著降低;衰减值和回生值分别比粳米粉高了33.73 RVU和50.60 RVU;与单一体系相比,由复配粉体系制成的米线呈现较好的硬度、弹性、韧性、蒸煮性和物理性质。当绿豆淀粉∶粳米粉为1∶1时,其制得的米粉的质构性质最好。     

Quality and antioxidant properties of functional rice muffins enriched with shiitake mushroom and carrot pomace

This study developed functional muffin by incorporating bioactive-rich food materials into rice muffin formulation. Rice flour was progressively replaced with shiitake mushroom powder (MP) and carrot pomace powder (CP) and effects on pasting, physical and textural properties, as well as the antioxidant activity and consumer acceptability, were evaluated. The pasting properties of rice flour were significantly influenced (P < 0.05) by MP and CP incorporation. The additional increase in the levels of MP and CP decreased the volume of enriched muffins with a subsequent increase in weight and hardness. Higher polyphenol and carotenoid contents were observed in enriched muffins, exhibiting higher 2,2-Diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity compared to rice muffins. Sensory result revealed enriched muffins to have comparable and better consumer acceptability than rice muffin. Improvement in antioxidant properties of the developed functional rice muffins by MP and CP incorporation makes it a potential snack, suitable for consumption for its health benefits.     

Effect of fertiliser on functional properties of flour from four rice varieties grown in Sri Lanka

BACKGROUND: Fertiliser is an essential agro‐chemical input in modern rice farming. Fertiliser affects the grain quality and yield of rice. Although much research has been carried out to investigate the influence of fertiliser (recommended NPK addition) on yield and quality of rice grain, little is known about the effect of fertiliser on thermal, pasting, gelling and retrogradation properties of rice flour. The aim of this study was to investigate the influence of recommended fertilisation on functional properties of rice flour from four popular high yielding rice varieties grown in Sri Lanka. RESULTS: Fertiliser (recommended NPK addition) increased the protein content but reduced the apparent amylose content in rice flour except in BG 357. Swelling power and amylose leaching of rice flour were also increased. Pasting onset temperature, cold paste viscosity and setback were increased but peak viscosity and granular breakdown decreased. In response to the fertiliser application, gelatinisation peak temperature was reduced in all varieties except BG 300. However, compared to pasting properties, gelatinisation parameters were not much affected by fertilisation. The extent of amylopectin retrogradation was decreased by fertiliser in BG 305 and BG 352 but unchanged in the other two varieties. Except in BG 305, fertiliser reduced the gel hardness of rice flour but increased the gel cohesiveness. CONCLUSION: It is apparent that the increased protein and reduced amylose content caused by fertiliser affect the functional properties of rice flour. Copyright © 2011 Society of Chemical Industry     

Effects of protein and transglutaminase on the preparation of gluten-free rice bread

Effects of transglutaminase (TGase) and proteins such as whey protein, caseinate, and soy protein on the preparation of gluten-free rice breads using non-waxy rice flour were investigated. Rice flour (about 12% moisture content) was prepared from dry milling of dried grain after rice got soaked. Unlike general dry milled flour, newly developed rice flour increased water binding capacity (WBC), swelling power, and peak viscosity. Soy protein increased WBC but other proteins slightly decreased with the increase of levels. Lightness decreased and yellowness increased with the addition of whey and soy protein. All pasting viscosities decreased with the addition of protein. The TGase improved the network structure of rice batter. The 2^nd proof time of rice batter with protein was shortened by 4–9 min with the addition of TGase. The specific volumes of rice breads with whey and soy protein also increased. TGase and protein additions decreased the hardness of rice bread. Sensory test showed that roasted flavor, volume, air cell homogeneity, and overall quality were significantly different (p<0.05) with protein and TGase additions.     

碱提残余蛋白对籼米糊化特性的影响

通过碱处理籼米粉(蛋白含量为7.85%)分离得到蛋白含量分别为2.36%,4.23%,0.38%的籼米淀粉、黄淀粉和白淀粉,并对3种淀粉的糊化与结构特性进行研究。RVA分析结果表明,籼米粉的糊化峰值粘度、热糊粘度和最终粘度均极显著低于籼米淀粉、黄淀粉与白淀粉(P0.01),与DSC对样品糊化温度的分析结果一致;RVA分析发现籼米淀粉和黄淀粉的粘度值没有显著差异(P0.05),而DSC结果表明黄淀粉和白淀粉的糊化温度最为接近。对样品的结构进行分析发现:碱处理籼米粉后3种淀粉的透光率均降低;平均链长白淀粉最长、籼米粉最短,聚合度白淀粉最大、籼米粉最小,黄淀粉和籼米淀粉的聚合度和直、支链淀粉的链长接近;蛋白亚基籼米粉和籼米淀粉主要含60,33,22,13ku亚基,黄淀粉主要含60,22,13ku亚基,白淀粉中主要含60,33ku亚基。显微结构分析发现不同的淀粉中,存在少量的蛋白质和纤维素。说明淀粉以外,蛋白质的含量与组成及其与纤维素的相互作用对籼米粉的糊化特性也有一定的影响。     

大米谷蛋白对大米淀粉理化特性的影响

本文研究了低变性大米谷蛋白的添加对大米淀粉的持水、糊化、流变与质构特性的影响。结果表明,大米谷蛋白的添加(0~20%)会逐渐降低大米淀粉的持水能力,延迟其水化过程。淀粉的黏度特性曲线、糊化晗值、峰值黏度、崩解值和回生值随谷蛋白添加量的增加而逐渐降低,但起始糊化温度和峰值温度无明显变化。流变数据证实,蛋白添加量为0~10%时,淀粉-蛋白复合物的剪切应力和表观粘度随添加量增加而增加,当谷蛋白添加量为20%时,复合物的剪切应力和表观粘度迅速减小,大米淀粉的糊化特性和凝胶特性发生明显弱化。     

Comparison of physical and chemical properties of medium-grain rice cultivars grown in California and Arkansas

ABSTRACT:  The physical attributes, chemical composition, and physicochemical properties of 2 medium-grain rice cultivars from Arkansas (Bengal, Medark) and from California (M202, M204) were compared when grown in their respective locations and grown together in Arkansas to better understand the impacts of heredity and environment on medium-grain rice quality. Variations existed in grain dimensions, particularly length distribution, among cultivars and between crop years. When grown separately, the Arkansas cultivars tended to have higher protein and lipid contents but lower amylose contents than the California cultivars. M204 contained a significantly higher apparent amylose content (21.0%) compared with the other 3 cultivars (14.3% to 16.4%). The Arkansas rice cultivars exhibited higher pasting and gelatinization temperatures and produced harder gels and less sticky cooked rice. However, when the 4 cultivars were grown together in Arkansas, differences in protein and amylose contents, gelatinization and pasting properties, and cooked rice texture decreased. This study demonstrated that genetics, location, and crop year all contributed to variations in rice chemical and physical characteristics.     

Influence of free‐air CO2 enrichment (FACE) on the eating quality of rice

Rice plants (Oryza sativa L cv Akitakomachi) were grown under free‐air CO₂ enrichment (FACE) in farmers' fields in Shizukuishi, Iwate, Japan during 1999 and 2000. The grains were harvested and subsequently analyzed for protein and amylose contents as well as the traits related to cooked‐rice viscosity. The cooked rice was also subjected to sensory evaluation. The protein content of rice grains grown under elevated CO₂ was significantly lower than that of rice grown under ambient conditions. In addition, CO₂ enrichment increased the whiteness of the grains in both brown and milled rice and reduced their surface hardness. Although the amylose content of rice grains was unaffected, starch pasting properties demonstrated that rice grains in elevated CO₂ had higher maximum viscosity and breakdown than those grown in ambient conditions. Sensory evaluation of cooked rice with respect to umami (deliciousness), appearance, aroma, hardness, stickiness and overall palatability index indicated that the sensory properties were not significantly altered by the CO₂ enrichment treatment. Therefore, we conclude that the growth of the rice cultivar Akitakomachi under elevated CO₂ concentration decreased the protein content, but did not change the palatability to a level that may be detected by sensory taste panel evaluation. Copyright © 2005 Society of Chemical Industry     

芭蕉芋淀粉对米粉理化性质及粉丝品质的影响

将芭蕉芋淀粉和籼米粉按照一定比例复配并制作粉丝,以复配粉的溶胀性质、热特性、糊化特性、流变学特性为理化性质测定指标,以粉丝的质构特性、蒸煮性质、感官品质为其质量评价指标,考察了芭蕉芋淀粉对米粉理化性质和粉丝品质的影响。结果表明：随着芭蕉芋淀粉添加量的增加,复配粉的直链淀粉含量、膨润力、峰值黏度、最低黏度、降落值、糊化焓、回生焓、回生度、弹性模量、黏性模量增加,而溶解度、最终黏度、回升值、糊化温度逐渐降低;米粉丝的硬度、弹性、黏附性、咀嚼性随芭蕉芋淀粉添加量的增加而增大。与纯籼米粉粉丝相比,复配粉米粉丝的筋道感和柔韧度增强,其光滑度却下降。综合考虑,添加2%～5%芭蕉芋淀粉的米粉丝品质最佳,具有很好的可接受性。     

Salt stress induces physiochemical alterations in rice grain composition and quality

Salinity has drastic effects on plant growth and productivity and is one of the major factors responsible for crop yield losses throughout the agricultural soils of the world. The mechanisms of salinity tolerance in plants are regulated by a set of inherent multigenes and prevalent environmental factors, which bring about a myriad of metabolic changes in each plant part. The stress-induced metabolic changes in the rice plant have been intensively studied, but extensively in plant parts such as stem, leaf, and root. However, little information exists in the literature about such stress-induced architectural and physiological changes in rice grain, a premier staple food of a large proportion of human population. Thus, the current review comprehensively describes the effects of salinity stress on rice grain composition including changes in carbohydrate, protein, fat, and mineral contents. Elucidation of salinity induced changes in rice grain composition would help to understand whether or not a nutritious and healthy staple food is available to human population from rice grown under saline environments.     

Impact of brown foxtail millet (Setaria italica) flour on thermo-mechanical properties of flours from different rice varieties

The physical, functional and thermo-mechanical properties of rice flours prepared from long, round and medium rice grain and of foxtail millet (Setaria italica) flour were investigated. The impact of foxtail millet flour addition on the thermo-mechanical properties to the rice flours was also explored. Rice flour from long grain had higher amylose content (26.37%), while the rice flour from round grain had better hydration properties compared to the other rice flours. The dough from long grain rice flour exhibited higher starch gelatinisation temperature and cooking stability and lower starch retrogradation compared to the other investigated rice flours. Foxtail millet flour addition to the rice flours exerted a lower impact on the thermo-mechanical properties of the dough based on rice flour from long grain compared to the other investigated rice flours. These differences might be due to the differences in terms of starch properties and proximate composition of the flour samples.     

蛋白组分对籼米粉糊化特性的影响机理探讨

通过逐一去除蛋白组分的方法研究了蛋白组分对籼米粉糊化特性的影响,并分析了影响这些变化的蛋白结构基础。RVA和DSC分析结果表明,不同组分的蛋白在去除之后,峰值粘度、热糊粘度和最终粘度均有不同程度的升高,崩解值、回生值及糊化温度均有不同程度的降低。SDS-PAGE和显微结构分析表明,各组分对糊化特性的影响机理应有差异:谷蛋白通过与纤维素类物质的紧密结合,在糊化过程中阻碍淀粉粒的溶胀;醇溶蛋白可能是通过蛋白体自身的溶胀与淀粉相互作用而影响;清、球蛋白通过活性蛋白对籼米成分的水解或合成等改变而影响;淀粉粒结合蛋白则可能对籼米的基础糊化特性影响较大。与分离重组法比较,逐一去除蛋白组分的方法因为蛋白组分之间的相互作用影响较大,对糊化特性的影响与分离重组法略有差异。     

籼稻后熟对米粉品质的影响研究进展

文章综述了籼稻后熟作用对米粉品质的宏观影响,分析了影响米粉品质变化的后熟原料籼米粉的理化性质(糊化特性、质构特性、水合特性)变化,及相应淀粉、蛋白质和脂肪等主要大分子的结构变化及其相互作用与米粉品质变化的相关性.     

Effects of potato starch on the characteristics,microstructures and quality attributes of indica rice flour and instant rice noodles

The effects of partial replacement (0%–20%, w/w) of rice flour by potato starch (PS) on the physicochemical properties, microstructures, texture and in vitro digestibility of indica rice flour (IRF) and instant rice noodles (IRN) were systematically investigated. Accordingly, the addition of PS significantly increased the peak viscosity (2876.00–3221.00 mPa·s) and tan δ values (0.14–0.22) but lowered the setback values (2169.00–1036.50 mPa) of the pastes. Rice noodles with 5%–15% PS (PS and IRF at the mixing ratios of 5:95, 10:90, 15:85 and 20:80, respectively) addition exhibited modulated appearance and textural properties. The mutually exclusive phosphate groups of PS facilitated the expansion of starch granules, contributing to the formation of more compact microstructure and higher-ordered crystalline structures (confirmed by scanning electron microscope and X-ray diffraction), endowing rice noodles with better cooking and digestive attributes, and visibly increased slowly digestible starches content (26.09%–31.34%). The quality attributes of rice noodles could be accurately predicted by the physicochemical properties of rice flour referring to Pearson’s correlation analysis. The study demonstrates that the blending of PS is both an effective and economical pathway in improving the nutritional and textural properties of IRN.     

Transglutaminase treatment of brown rice flour: A chromatographic, electrophoretic and spectroscopic study of protein modifications

Recently, it was shown that transglutaminase (TGase) treatment of brown rice (BR) flour results in textural improvements of gluten-free bread. In this study, changes in the protein profiles of BR flour and protein fractions induced by TGase treatment were investigated to better understand the activity and specificity of the enzyme. Size-exclusion HPLC (SE-HPLC) profiles of flour extracts, under reducing conditions, revealed the presence of macromolecular protein complexes, as well as low molecular weight proteins. After TGase treatments (10 U/g of proteins) a general reduction in peak intensities indicated the polymerisation of BR proteins into larger, insoluble complexes. Microchip capillary electrophoresis and two-dimensional (2D) gel electrophoresis revealed that the α and β glutelin subunits were primary substrates for the polymerisation reaction, whereas albumins and globulins were only slightly affected. SE-HPLC of the protein fractions revealed glutelins’ polymerisation into high molecular weight structures after TGase treatment. Dynamic light scattering measurements showed that new supramolecular aggregates of glutelins co-existed with the macromolecular complexes already present in the untreated fraction. Front-face fluorescence approaches indicated that TGase treatment caused a decrease in protein surface hydrophobicity of BR flour, but not of the glutelin suspensions. It is concluded that the large protein complexes resulting from glutelin polymerisation and the stronger hydrophobic interactions among proteins result in the improved textural properties of TGase-treated BR bread.     

冰湖野米粉及其淀粉的精细结构、理化和消化特性研究

目的 探究冰湖野米粉及其淀粉的理化性质、结构特性和消化性的差异, 同时揭示不同级的冰湖野米淀粉的精细结构。方法 以3种不同级的冰湖野米和1种早籼米(对照组)为原料, 将其研磨过筛制备米粉样品, 再用焦亚硫酸钠法和甲苯法进行纯化得到对应的淀粉样品。采用体积排阻色谱分析法(Size exclusion chromatography, SEC)与荧光辅助毛细管电泳法(Fluorescence assisted capillary electrophoresis, FACE)测定冰湖野米淀粉的精细结构(直链淀粉和支链淀粉的链长分布); 利用扫描电镜、光学显微镜、X-射线衍射仪、傅里叶变换红外光谱仪和布拉班徳粘度仪等现代分析仪器对冰湖野米粉及其淀粉的理化性质和结构特性进行测定; 采用Englyst体外消化法测定冰湖野米粉及其淀粉的体外消化性。结果 研究表明, 不同级的冰湖野米粉及其淀粉的颗粒形貌特征、粘度特性、结晶结构以及直链淀粉含量无显著差异。与早籼米相比, 冰湖野米粉及其淀粉的起糊温度高, 峰值粘度低, 相对结晶度低, 热稳定性好, 慢消化淀粉和抗性淀粉含量高, 主要归因于冰湖野米的支链淀粉结构及其较高的直链淀粉含量。与冰湖野米淀粉相比, 冰湖野米粉颗粒更大, 结晶度降低, 膨胀度降低, 慢消化性增加, 主要归因于冰湖野米粉中较高的内源蛋白和纤维含量。结论 冰湖野米中的内源纤维、蛋白质、直链及支链淀粉含量对冰湖野米的粘度特性、膨胀度、结构特性以及消化性有显著的影响。     

Physicochemical Characterization and Consumer Acceptance by Asian Consumers of Aromatic Jasmine Rice

ABSTRACT: Physicochemical properties and acceptance by Asian consumers in the United States of 3 commercially U. S.-grown and 12 imported jasmine rice samples were evaluated. Rice kernels, flour, and starch were characterized for physical, chemical, pasting, and thermal properties. Amylose content, gel type, hardness-to-stickiness ratio, surface fat, protein, and pasting properties significantly affected the eating and cooking qualities and physical appearances of the rice samples; these variables were key to distinguishing the major quality differences and to differentiating U. S.-grown from imported jasmine rice. Data collected from this study could be useful to rice producers, importers, or rice breeders for understanding the physicochemical characteristics of aromatic jasmine rice and its acceptance by Asian consumers.     

模拟传统柴火烹饪方式对米饭食味及蛋白质营养特性的影响

研究不同烹制方式对米饭食味品质、蛋白质营养特性的影响。结果表明,烹制方式对米饭食味品质和蛋白质营养特性具有较大影响,快速米饭和柴火米饭比传统柴火米饭滋味好,硬度大、黏弹性好,挥发性风味物质种类多。传统柴火米饭醛、醇挥发性物质总量、必需氨基酸指数较高。电饭煲烹制方式对米饭香气、滋味、挥发性风味物质、还原糖、质地、氨基酸组成均具有较大影响,柴火米饭香气、滋味较好,醛、酮、醇、酚挥发性物质总量较高,且质地柔软黏弹、必需氨基酸指数最高。主成分分析提取了前4个主成分,累计方差贡献率达到88.22%,表明不同烹制方式米饭食味与营养品质可以分为非必需氨基酸组成、挥发性风味物质与必需氨基酸组成、外观特性和黏弹性、感官品质4类,主成分综合评分得分顺序由高到低分别是传统柴火米饭、柴火米饭、快速米饭。