稻米中蛋白质对淀粉RVA特征谱的影响

通过分析蛋白酶或还原剂二巯基苏糖醇（DTT）分别去除稻米蛋白质或打破蛋白质二硫键后,稻米RVA（Rapid Visco Analyzer）特征谱形成和特征值的变化,研究蛋白质对淀粉RVA特征谱的影响,以及对米饭食味品质的作用。在淀粉糊化过程中,蛋白质使RVA特征谱的峰值黏度、冷胶黏度等值升高,改变RVA线性上升段的斜率。蛋白质可能通过二硫键结合形成的蛋白质网络本身和通过吸水减少淀粉水合的有效水量,协同提高糊化多相体系的浓度,增强分散相与黏稠相的互作。蛋白质影响米饭食味品质,可能通过改变米粒的吸水性而起作用。     

Impact of proteins on pasting and cooking properties of waxy and non-waxy rice

Changes of RVA viscosity and texture properties of waxy rice (n=9) and non-waxy rice (n=10) were analyzed through protein removal or disulfide bond disruption. Protease or DTT had similar effects on the pasting behavior of the waxy rice, but affected differently that of non-waxy rice. For all waxy rice flour treated with DTT or protease, the peak, breakdown and consistency viscosity values all significantly decreased, and the viscosity curves barely rose from the baseline. Pre-incubation of flours with a protease increased RVA pasting temperatures, decreased viscosities along all the points of the curves and the slopes of the linear parts of the curves for all non-waxy cultivars. DTT decreased RVA pasting temperatures and peak viscosities of all non-waxy flour, but increased breakdown viscosities in six non-waxy rice cultivars. With DTT-added cooking water, the hardness of cooked waxy and non-waxy rice, as determined by Instron, generally decreased. With DTT-added cooking water, the adhesiveness of all cooked waxy rice significantly decreased, while it increased significantly or remained the same in all cooked non-waxy rice. The above results indicated that the protein agent of a network linked by disulfide bonds increased the RVA gelatinized paste rigidity, the hardness and adhesiveness of cooked rice of all waxy cultivars, while in non-waxy cultivars, both the network and the increase of the gelatinized paste concentrations resulting from protein hydration contributed to the enhancements of the RVA paste rigidity and the cooked rice hardness.     

煮饭水质结合加水量和浸泡时间对粳稻食味的影响

以津川1号和津原E28为材料,采用自来水和纯净水煮饭,通过米饭感官评价和质地测定,明确水质对其食味的影响,同时研究这种影响是否与煮饭时的加水量和浸泡时间有关。结果表明,随加水量的增加,米饭外观、饭香、味道和综合评价感官得分先增大后减小,米水质量比为1:1.50时上述指标得分最高,食味最好;米水质量比在1:1.25~1.50范围内,用纯净水蒸煮的米饭的味道和粘度感官得分要高于用自来水蒸煮的米饭。随煮饭加水量的增加,米饭的硬度下降、粘度增加,与感官评价结果一致。随大米浸泡时间延长,米饭外观、味道、粘度和综合评价感官得分先增加后减小,浸泡1.0 h,上述指标得分最高,食味最好。浸泡时间延长会降低米饭的饭香。在浸泡时间15.0 h内,与用自来水浸泡后蒸煮相比,用纯净水浸泡后蒸煮的米饭食味感官综合评价更高。综上,对津川1号和津原E28而言,米水质量比为1:1.50,浸泡1.0 h,使用纯净水煮饭可以获得更好的食味。     

施氮量对机插稻主要米质性状的影响

以粳型超级稻宁粳3号和常规粳稻镇稻11号为材料,在机械插秧条件下,研究施氮量(0、90、180、270、360 kg/hm2)对粳型超级稻主要米质性状及淀粉粘滞谱(RVA谱)特征的影响。结果表明:施氮量对两个品种的稻米加工品质、营养品质、蒸煮食味品质及淀粉RVA谱3个曲线峰值的影响达到显著或极显著水平,对淀粉RVA谱其他特征参数的影响因不同品种而异;增加施氮量使两品种外观品质变差。随施氮量的增加,两个品种的糙米率、精米率、整精米、精米蛋白质含量呈增加趋势,而稻米的直链淀粉含量、食味值和淀粉RVA谱曲线峰值(峰值黏度、热浆黏度和冷胶黏度)呈现下降趋势。表明增施氮肥在提高粳型超级稻和常规粳稻加工和营养品质的同时,降低了稻米食味品质,并使稻米淀粉粘性变劣。     

小麦淀粉与面条质量关系的研究进展

小麦淀粉品质对白盐面条的质量（尤其是煮后的感官特性）有重要影响。直链与支链淀粉的含量及比例是影响面条质量的重要因素,是造成不同小麦品种淀粉糊化和膨胀特性及面条质量差异的物质基础。较低直链淀粉含量的小麦粉具有较好的糊化和膨胀特性,制作的面条煮制时吸水率高,烹调损失低,具有较高的感官评分。优质白盐面条的直链淀粉含量应在22%左右。峰值黏度、稀懈值、峰值时间是影响面条质量的重要糊化参数,这3项参数高的小麦粉适合制作优质面条。高膨胀势或膨胀体积的小麦粉制作的面条中等偏软,光滑且富有弹性,可以作为面条用小麦的重要选择标准。一般认为,直链淀粉含量较低、峰值黏度和稀懈值高、峰值时间长、膨胀势或膨胀体积高的小麦粉适合制作优质白盐面条。其中,直链淀粉含量、峰值黏度和膨胀势是优质面条小麦评价的关键品质性状。     

Effects of added water and retrogradation on starch digestibility of cooked rice flours with different amylose content

Flours derived from rice varieties with different amylose content possess distinct physicochemical and molecular properties. The aim of this study was to determine optimal processing conditions for preparing rice flour-based foods with reduced starch digestibility. To do so, we evaluated the in vitro starch digestibility of rice flours with five varieties. Reducing the amount of water (from 10-fold to 4-fold of rice flour) used for cooking rice flour lowered its starch digestibility, and the magnitude of the decrease was positively correlated with amylose content. When retrogradation of cooked rice flour proceeded for 7 days, the digestibility of high-amylose rice flours declined rapidly in the first 3 days, whereas the digestibility of low-amylose rice flours declined continuously. Our analysis also demonstrated that the chain length distribution of starch molecules and the final and setback viscosity pasting properties were the most important parameters affecting the digestibility of rice flours. Based on our results, it appears possible to reduce rice starch digestibility by establishing optimum processing conditions for different varieties. We suggest a 7-fold addition of water and retrogradation for 1 day for high-amylose rice varieties and a 4-fold addition of water with 3 days of retrogradation for low-amylose rice.     

蛋白质影响水稻米饭食味品质的机理

 以杂交中籼丰两优1号组合为材料,设置不同的播期和收获期,分析稻米主要品质指标(直链淀粉、总蛋白含量、RVA特征值等)和米饭食味品质,并用二硫苏糖醇 (DTT)或蛋白酶(Trypsin)分别打破样品蛋白质二硫键或酶解蛋白质后,观察RVA特征谱和膨胀势的变化,旨在明确蛋白质对不同食味品质样品RVA的影响,进而探索蛋白质影响米饭食味品质的机理。结果表明,第3播期(6月13日)稻米品质主要指标（直链淀粉、总蛋白、膨胀势、RVA特征值）与第4播期（6月23日）样品差异不显著,但食味品质明显好于后者;分别经蛋白酶处理后,第3和第4播期样品RVA上升段斜率差异不显著,但前者后段冷却后回升斜率明显小于第4播期。由于影响RVA特征谱后段凝胶刚性的主要因素是淀粉与水之比,刚性随淀粉凝胶中含水量减少而提高,食味品质较好的第3播期米粉经蛋白酶处理后,凝胶刚性小且减弱程度大,这可能是蛋白质酶解后形成蛋白质碎片的持水能力弱,即淀粉与水之比低,由此推测蛋白质影响米饭食味品质可能在米饭蒸煮后阶段,即可能与蛋白质水合后持水能力差异有关。     

Effects of prolamin on the textural and pasting properties of rice flour and starch

Prolamin is a major class of rice proteins but its influence on the physicochemical properties of rice is not clear. Rapid Visco Analyser (RVA) and TA-XT2 TPA textural analyses were performed on rice starch with the addition of prolamin extracted from three rice cultivars (Hitomebore, M103 and Amaroo), and on rice flour with the prolamin removed by propan-2-ol extraction. Addition of prolamin to rice starch was found to cause a significant (P<0.05) increase in RVA breakdown viscosity but significant (P<0.05) decreases in hardness, adhesiveness and gumminess of the starch gel. Similarly, when prolamin was removed from rice flour, exactly the opposite effect was observed. Addition of prolamin to rice starch also caused it to absorb water faster during cooking but the gelatinised starch absorbed less water compared with control samples without prolamin.     

Allelic Effects on Eating and Cooking Quality of SSⅡa and PUL Genes Under Wxmp Background in Rice

【Objective】Our aim is to analyze the genetic effects of soluble starch synthase gene SSⅡa and debranching enzyme gene PUL on eating and cooking quality under the same main gene background of Wxmp, so as to lay a theoretical basis for rice quality improvement. 【Method】In this study, a semi-glutinous rice line Ning 0145 and japonica rice variety Wuyunjing 21 were crossed to obtain F2 population and F3 lines. There was polymorphism in soluble starch synthase gene SSⅡa and debranching enzyme gene PUL but no polymorphism in other starch synthase related genes between the two parents. With molecular markers, some F2 plants and F3 lines containing Wxmp gene were selected and divided into four genotypes, SSⅡanPULn, SSⅡanPULw, SSⅡawPULnand SSⅡawPULw(n and w indicated that the genes were contributed by Ning 0145 and Wuyunjing 21, respectively). The allelic effects of SSⅡa and PUL genes on eating and cooking quality under the same Wxmp gene background was investigated by analyzing the eating and cooking quality and its differences among different genotypes. 【Result】There were significant differences for eating and cooking quality among genotypes of different parental origins. The allelic gene SSⅡaw and PULw from Wuyunjing 21 increased amylose content by 0.29%–1.00% and 0.62%–1.18% respectively, and the effect of PUL was greater than that of SSⅡa. There was interaction between SSⅡa and PUL genes. The SSⅡaw and PULw genes also decreased gel consistency and breakdown viscosity, increased hot paste viscosity, cool paste viscosity, setback viscosity and consistency viscosity, but had little effect on gelatinization temperature, peak viscosity and peak time. 【Conclusion】The genetic effects of SSⅡa and PUL genes on cooking and eating quality of rice under the background of Wxmp gene were clarified. The results lay a theoretical basis for improving rice quality by molecular marker-assisted selection of SSⅡa and PUL genes.     

Effects of Variations in Starch Synthase on Starch Properties and Eating Quality of Rice

Abstract

We evaluated the effects of functional variation in three starch synthases in rice (Oryza sativa L.)?granule-bound starch synthase I (GBSSI, wx), starch synthase I (SSI, SSI), and starch synthase IIa (SSIIa, alk)?between indica cultivar Kasalath and japonica cultivar Nipponbare on starch properties and eating quality. We used three near-isogenic lines?NIL(Wx^a), NIL(SSI ^k), and NIL(Alk)?containing chromosomal segments of Kasalath on a Nipponbare genetic background. The Wx^a allele explained most of the difference in amylose content between the two cultivars, and decreased the peak viscosity and breakdown to less than half of those of Nipponbare. These changes reduced the quality of cooked rice both just after cooking and after storage at 5ºC. The variation in SSIIa also affected the eating quality after storage of cooked rice at 5ºC : NIL(Alk) became harder and less sticky than Nipponbare, although the rices were comparable just after cooking. Differential scanning calorimetry revealed faster retrogradation of the once-gelatinized starch in NIL(Alk). The variation in SSI alleles hardly affected these properties.     

The Null-4A Allele at the Waxy Locus in Durum Wheat affects Pasta Cooking Quality

Granule-bound starch synthase, also known as the waxy protein catalyses the synthesis of amylose in wheat endosperm starch. In durum wheats, the genes encoding GBSS are present at the two Wx loci on chromosome 7A and 4A (a segment of 7B that has been translocated). Several null Wx-B1 (missing GBSS protein from chromosome 4A) durum lines were produced from crosses with null-4A bread wheats backcrossed to durum wheats. Semolina milled from 4 normal and 7 null-4A durum wheat lines grown over two seasons (1999 and 2000) in South Australia were analysed for amylose content, starch pasting properties as measured by the Rapid Viscoanalyzer (RVA), swelling power and starch damage, protein content and electrophoretic protein analysis. Spaghetti was prepared with a micro-scale extruder and the cooked pasta evaluated for cooking loss, firmness, stickiness and water absorption. The null-4A lines had significantly lower (ca. 5%) amylose content, higher starch peak viscosities and semolina swelling power. The pasta derived from the null-4A lines had lower cooking loss and in 1999 was more adhesive than the non-waxy lines. Cooking loss was correlated with amylose content, peak starch viscosity, swelling power of semolina and cooked pasta adhesiveness. Semolina swelling power was highly correlated with RVA peak viscosity. Waxy durum wheats appear to have an advantage over the normal types in terms of lower cooking loss, widely used as an indicator of pasta cooking quality.     

Effect of Stewing in Cooking Step on Textural and Morphological Properties of Cooked Rice

Stewing of rice grains by steam after boiling in excess water can be used for cooking rice perfectly. The effects of this procedure in cooking of three varieties of Iranian rice (Sang Tarom, Domsiyah and Fajr) on textural and morphological properties of cooked rice grains were investigated. The results showed that this step in rice cooking reduced the hardness and increased the adhesiveness of rice grains significantly. By the use of the scanning electron microscopy, it was shown that the outer surface of cooked rice stewed by steam had less porosity and closer pores due to the modification during cooking, and better gelatinization and more expansion of starch granules compared to non-stewed samples. The use of this procedure in rice cooking to provide a fully cooked and gelatinized, softer and stickier final product is recommended.     

In vitro starch digestibility,degree of gelatinization and functional properties of twin screw prepared cereal-legume pasta

The investigation explores the possibility of utilizing legume flour (pigeon pea:10–30%) and brown rice flour (35–45%) for production of pasta using twin screw extruder. RSM was used to analyse the effect of feed moisture (28–36%), barrel temperature (70–110 °C) and legume:brown rice ratio on quality responses (in vitro starch and protein digestibility, degree of starch gelatinization, cooking quality, pasting properties, color and textural properties) of pasta. Extrusion processing significantly enhanced in vitro starch and protein digestibility of prepared pasta. The in vitro starch and protein digestibility of pasta ranged between 15.00 and 26.77 g/100 g and 50.34–84.82 g/100 g respectively. Addition of brown rice flour and pigeon pea flour exhibited dominating positive effect on cooking quality of the pasta. Degree of gelatinization of prepared pasta was found in range of 52.13–90.10 per cent. Color characteristics viz. luminosity, redness and yellowness of pasta enhanced with feed moisture. Pasting properties revealed lower peak and final viscosity at higher processing conditions. Firmness of cooked pasta elevated with an increase in the barrel temperature. Acceptability score of health based pasta on the basis of sensory attributes was 8 as inferred from 9 point hedonic scale.     

Starch gelatinization distribution and peripheral cell disruption in cooking rice grains monitored by microscopy

Starch gelatinization kinetics governs rice cooking behaviour (cooking time and texture). Starch gelatinization however occurs unevenly in the cooking grain. The aim of this study was to investigate the dynamics of starch gelatinization topography in rice kernels cooked in excess water at two temperatures: 75 °C and 95 °C, for times ranging from 5 to 30 min. Gelatinization front position was assessed over time on 40 μm cross sections using four different tracking methods: directly or after iodine staining using a microscope or a stereomicroscope under normal or polarized light. The four methods gave similar results and the obtained kinetics can be used to model starch gelatinization during grain cooking.In parallel, changes in the structure of the peripheral area of cooked grains were investigated on 3 μm cross sections under the same cooking conditions. Microscopic observations by auto fluorescence and after iodine staining revealed dynamic peripheral cell disruption at the same time as starch gelatinization, which may have a major impact on starch leaching and hence on the textural properties of the cooked grain.     

Variability in Grain Quality Characters of Upland Rice of Assam,India

The grain quality of 100 upland/ahu rice genotypes from Assam,India was assessed.The characteristics measured were grain length,grain width,cooked grain length,cooked grain width,grain elongation ratio after cooking,grain widening ratio after cooking,alkali spreading value,gel consistency,as well as starch,amylose,amylopectin and total soluble sugar contents.Considerable genetic variability among the 100 rice genotypes was observed for the characteristics under study.Analysis of variance revealed highly sig...     

Wx^mp基因背景下可溶性淀粉合成酶基因SSⅡa和去分支酶基因PUL对水稻蒸煮食味品质的影响

【目的】分析在同一主效基因(Wx^mp)背景下可溶性淀粉合成酶基因SSⅡa和去分支酶基因PUL对稻米蒸煮食味品质的影响,以期为水稻品质遗传改良提供依据。【方法】选择在SSⅡa和PUL存在多态性而其他淀粉合成酶相关基因没有多态性的半糯品系宁0145和粳稻品种武运粳21进行杂交,获得F2群体与F3株系。利用分子标记,选择含有Wx^mp基因的F2单株与F3株系,将这些F2单株与F3株系分成SSⅡa^nPUL^n、SSⅡa^nPUL^w、SSⅡa^wPUL^n和SSⅡa^wPUL^w4种基因型(n和w分别表示该基因来源于宁0145和武运粳21),分析不同基因型蒸煮食味品质性状的差异,探讨同一Wxmp基因背景下不同SSⅡa和PUL等位基因对蒸煮食味品质性状的影响。【结果】不同基因型间蒸煮食味品质性状均存在显著差异,来源于武运粳21的SSⅡa^w基因和PUL^w基因分别使直链淀粉含量增加0.29%~1.00%和0.62%~1.18%,且PUL的效应大于SSⅡa,两者间存在互作效应。SSⅡa^w基因和PUL^w基因降低胶稠度和崩解值,提高了热浆黏度、冷胶黏度、消减值和回复值,对糊化温度、峰值黏度和峰值时间的作用较小。【结论】明确了Wx^mp背景下SSⅡa和PUL基因对稻米蒸煮食味品质的遗传效应,该研究结果为SSⅡa和PUL基因的分子标记辅助选择改良稻米品质提供了理论依据。     

Effects of altitude above sea level on the cooking time and nutritional value of common beans

The present study was conducted with the objective to determine the effects of altitude above sea level, on the cooking time and nutritional value of common black beans (Phaseolus vulgaris). Three 100 g samples of theOstua variety were cooked at 8 individual locations, ranging in altitude from 0 to 2256 meters, in Guatemala, to establish water uptake and cooking time. The cooked samples were separated into cooked beans and cooking broth for chemical analysis. This included moisture, protein, lysine, tannins, total and enzyme susceptible starch, and fiber fractionation. The cooking liquor was analyzed for total solids, moisture, protein, ash and K. A 1200 g sample was cooked for the cooking time established previously, for biological testing of nutritional value,which included Net Protein Ratio (NPR), Protein Effciency Ratio (PER), and protein digestibility. Altitude influenced cooking time which increased from 78 min at 0 m, to 264 min at 2256 m. Final moisture content in the cooked bean was similar at all altitudes and there was a tendency to yield smaller amounts of solids in the cooking broth at higher altitudes. The increase in cooking time was significant. Bean water uptake at all times was significantly slower and smaller at ambient T, as compared to water uptake at boiling T, at all altitudes. Protein and lysine content were not affected by altitude, however, tannin and catechin were lower in cooked samples, as compared to the raw material. Altitude did not affect the content of these substances. Total starch and total sugars were higher in the raw sample, as compared to the cooked samples, but there was no effect of altitude. Enzyme susceptible starch (ESS) was lower in the raw sample as compared to the cooked samples, which contained similar amounts with respect to altitude. No change was observed in fiber fractions of the cooked beans. Likewise, the composition of the cooking broth was very similar between cooking locations. There was a small tendency to a lower protein quality, with respect to altitude, the effect of which was more obvious in the apparent protein digestibility values. Undercooking or overcooking at one location influenced protein quality values. The extended cooking time of beans at high altitudes, has important economic and environmental implications, since significant amounts of wood have to be used.     

Starch gelatinization distribution and peripheral cell disruption in cooking rice grains monitored by microscopy

Starch gelatinization kinetics governs rice cooking behaviour (cooking time and texture). Starch gelatinization however occurs unevenly in the cooking grain. The aim of this study was to investigate the dynamics of starch gelatinization topography in rice kernels cooked in excess water at two temperatures: 75 °C and 95 °C, for times ranging from 5 to 30 min. Gelatinization front position was assessed over time on 40 μm cross sections using four different tracking methods: directly or after iodine staining using a microscope or a stereomicroscope under normal or polarized light. The four methods gave similar results and the obtained kinetics can be used to model starch gelatinization during grain cooking.     

Rice-based pasta: A comparison between conventional pasta-making and extrusion-cooking

Good quality gluten-free products continue to be in demand among the celiac community and the production of pasta from non-conventional raw materials is a major technological challenge. In this work, the effects of two different pasta-making processes (conventional and extrusion-cooking) were investigated on parboiled brown and milled rice flours. The two processes differentiated for extrusion temperature (conventional extrusion: 50 °C, max; extrusion-cooking: 115 °C), whereas the drying diagram was the same. Starch modifications induced by each pasta-making process were analyzed by using a Micro-ViscoAmylo-graph (MVAG), Differential Scanning Calorimetry (DSC), and X-ray Diffraction. The cooking quality was evaluated by weight increase, solid loss into the cooking water, and texture analysis. Pasta obtained from milled rice using the extrusion-cooking process was characterized by the best cooking behavior. In this sample, starch presented the highest peak and final viscosities, the highest gelatinization temperature and lower enthalpy value, and the lowest crystallinity. The cooking quality of pasta obtained from brown rice appeared less affected by the processing conditions. Therefore, the nature and intensity of starch modifications can be modulated by the processing conditions and might explain the different cooking behaviour of rice pasta.     

稻米淀粉黏滞性(RVA谱)特征值的遗传及QTL定位分析

利用武育粳3号/Aichi 106构建的F2 群体,研究了精米粉RVA谱8个特征值: 最高黏度(peak viscosity,PKV)、热浆黏度(hot paste viscosity,HPV)、冷胶黏度(cool paste viscosity,CPV)、崩解值(breakdown viscosity,BDV)、消减值(setback viscosity,SBV)和回复值(consistence viscosity,CSV)、峰值时间（peak time, PeT）、糊化温度（pasting temperature, PaT）的遗传规律。结果表明, PKV为由微效基因控制的数量性状;HPV、CPV、SBV、BDV、CSV可能是由一对主基因和微效多基因共同控制的数量性状;PeT可能由两对主基因控制,并且还受微效多基因的影响。用热研2号/密阳23构建重组自交系群体,于2005-2006年对稻米淀粉RVA谱8个特征值进行了数量性状基因座QTL定位和分析,两年试验共检测到34个QTL,分布在第1、2、3、4、6、7、8共7条染色体上;两年同时检测到的QTL共8个,其中qHPV6、 qCPV6、 qCSV6、 qSBV6、qBDV6位于第6染色体的Wx基因附近;qHPV2、qCSV2位于第2染色体RM341与RM475标记之间,qCPV2位于RM573与RM250标记之间。第2染色体上与支链淀粉合成有关的两个基因与RVA谱特征值有密切关系。