Differential expressions among five Waxy alleles and their effects on the eating and cooking qualities in specialty rice cultivars

Eating and cooking qualities（ECQs） of rice are important attributes due to its major influence on consumer acceptability. To better understand the molecular mechanism of the variation in ECQs, we investigated and compared the expressions among different alleles of the Waxy（Wx） gene and its effect on ECQs in specialty rice cultivars. The results showed that the accumulation of amylose was positively and significantly correlated to the level of mature Wx m RNA and granule-bound starch synthase I（GBSS I） in developing rice grain at 12 days after flowering. The amount of GBSS I and its activity together are the main factors controlling amylose synthesis. Differences in ECQs among five Wx allele types were investigated in samples from 15 rice varieties. The apparent amylose content（AAC） and gel consistency（GC） were similar in each type of Wx allele. The AAC followed the order, Wx^a type〉Wx^in type〉Wx^b type〉Wx^mq type〉wx. Contrary to this, the GC showed an opposite trend compared to AAC. There was a wide variation in rapid visco analyzer（RVA） profile among five Wx allele types, while varieties sharing a specified Wx allele had basically the similar RVA profile, although there was a slight difference in some RVA parameters, peak, hot paste and cool paste viscosities.

富硒与普通稻米理化性质和蒸煮食味品质分析

富硒大米是人体日常重要的补硒来源,为了探究富硒处理对大米理化性质和蒸煮食味品质的影响,该研究以四个品种的籼稻(巨两优60、野香优航1573、虾稻一号、华夏香丝)和两个品种的粳稻(南粳5055、南粳9108)为实验原料,分析比较富硒组和对照组大米的基本理化特性和蒸煮食味品质。结果显示:硒促进了大米蛋白质的积累,与普通大米相比,富硒大米蛋白质含量增加了3 wt%~16 wt%;硒对大米糊化特性、质构特性、热学性质和蒸煮品质没有显著影响;硒显著降低了米饭的食味品质(P<0.05)。相关性分析结果显示硒与蛋白质和灰分的相关系数为0.54和0.46,与大米米饭硬度的相关系数为0.48,与米汤pH之间的相关系数为-0.55,与其他理化指标间几乎不存在相关关系;硒与米饭外观、口感和食味值之间呈负相关关系,相关系数分别为-0.62、-0.73、-0.79。与普通大米相比,富硒大米提升了总硒、蛋白质和无机物质的含量,提升了大米的营养品质,但却降低了其食味品质。本研究为富硒大米品质研究和深加工提供了理论参考。

脱乙酰魔芋葡甘露聚糖对挤压熟化米粉品质的影响

为探究脱乙酰魔芋葡甘露聚糖(deacetylated konjac glucomannan,DKGM)改善挤压熟化米粉品质的机制,该研究考察不同脱乙酰度DKGM(0%、27.62%、47.62%、59.81%、76.19%)对米粉糊化及流变性质、蒸煮品质、质构特性的影响,并通过X射线衍射、傅里叶变换红外光谱、扫描电镜探究其作用机理。结果表明,DKGM能显著缩短米粉的最佳蒸煮时间,降低断条率,增加透光率。其中适度脱乙酰的DKGM(47.62%)使米粉的蒸煮损失率由9.59%降至5.00%,硬度由1544.79 g降至1158.00 g。而高脱乙酰度DKGM(76.19%)组米粉蒸煮损失率仅比纯大米粉组降低了1.07%。X射线衍射分析表明DKGM能够抑制淀粉的重结晶,延缓老化。扫描电镜观察发现,添加DKGM使米粉具有更均匀的网络结构,但当DKGM脱乙酰度超过59.81%时,米粉结构变得松散。因此,添加适度脱乙酰的DKGM(47.62%)能够显著改善米粉蒸煮品质及质构特性。该研究可为DKGM在米制品中的应用提供理论依据,拓宽了魔芋葡甘露聚糖在食品加工中的应用。

谷朊粉对挂面血糖生成指数的影响及机理研究

为了改善普通挂面血糖指数偏高的现象,研究添加谷朊粉对小麦粉挂面体外血糖生成指数(eGI)的影响,并从挂面蒸煮特性、流变学特性、糊化特性和谷蛋白大聚体(GMP)等方面进行机理探讨。结果表明:当谷朊粉添加量分别为1%、5%、10%和15%时,挂面eGI逐渐降低且较普通挂面降低率分别为6.07%、8.97%、12.21%和14.76%;面条的硬度、咀嚼性、弹性和内聚力整体呈增大趋势,黏性降低,耐煮性增强;面团的韧性整体呈增大趋势,延展性和能量增大,糊化温度升高且热稳定性得到改善,GMP含量增加;面条eGI与面条黏性呈极显著正相关,与混粉峰值黏度、回生值和吸水率呈显著正相关,与熟面拉断力、延伸距离和延展性呈极显著负相关,与谷朊粉添加量、能量和GMP含量呈显著负相关;添加谷朊粉后蛋白网络结构更加致密宽厚,蛋白包裹淀粉颗粒的程度增加,淀粉糊化受到抑制。添加谷朊粉使包裹淀粉颗粒的面筋网络得到强化,抑制了淀粉的糊化,同时通过空间位阻抑制了淀粉的消化水解,使面条煮后eGI降低。

甘露糖赤藓糖醇脂对冷冻熟面品质的影响

为改善冷冻熟面在冻藏过程中易产生冰晶、品质劣变的现象,本研究以蔗糖酯(sucrose ester,SE)为对照添加剂,探究甘露糖赤藓糖醇脂(mannosylerythritol lipids,MELs)对冷冻熟面中可冻结水含量、水分分布、成品品质特性以及小麦粉糊化特性、蛋白二级结构的影响。结果表明,添加0.30%~1.10%MELs能够促进冷冻熟面中的自由水向结合水转化,降低可冻结水的含量,使水与蛋白、淀粉等大分子结合更牢固。与空白组和添加SE组样品相比,添加0.70%MELs制作的冷冻熟面品质较好,此时的硬度为(4335.317±48.047)g,比空白组增加25.36%;拉断力和拉断距离分别达到(11.22±0.15)g和(69.09±1.34)mm;吸水率显著增大,蒸煮损失率最小,优于SE的改善效果。同时,MELs可以有效延缓小麦粉淀粉老化速度,提升蛋白质二级结构中的β-折叠和α-螺旋含量,强化面筋网状结构。

Comparative analysis on grain quality and yield of different panicle weight indica-japonica hybrid rice(Oryza sativa L.) cultivars

Indica-japonica hybrid rice(Oryza sativa L.) cultivars showed high yield potential and poor tasting quality when compared with common japonica rice cultivars. Large panicle is a prominent factor of high yield for indica-japonica hybrid rice cultivars, and the panicle weight varies greatly among different indica-japonica hybrid rice cultivars. It is important to research on yield and grain quality of different panicle weight indica-japonica hybrid rice cultivars. In this study, two different panicle types indica-japonica hybrid cultivars were used to research on the relation of yield and grain quality. The yields of two heavy panicle weights indica-japonica hybrid cultivars were significantly higher than that of two medium panicle weight rice cultivars. The cooking and eating quality and starch properties of different panicle type cultivars were evaluated. Yongyou 6715(medium panicle) and Yongyou 1852(heavy panicle) got the relatively higher cooking and eating quality. Rice cultivars with medium panicle weight had more large starch granules and higher relative crystallinity than cultivars with heavy panicle weight. Transition temperature and retrogradation enthalpy(ΔHret) of medium panicle type cultivars were significantly higher than that of heavy panicle type cultivars. There was no significant difference in amylose content among different panicle type cultivars. Protein content of heavy panicle type cultivar was higher than that of medium panicle type cultivar, and protein content is the main factor affect cooking and eating quality in this study. The cultivar Yongyou 6715 got the highest taste value with the lowest protein content. Thus, it is suggested that the emphasis on improving rice cooking and eating quality of indica-japonica hybrid rice cultivars is how to reduce the protein content in rice grain. According to the results of this study, medium panicle type with high grain weight is the desired panicle type for high quality indica-japonica hybrid rice breeding.

Comparison of grain yield and quality of different types of japonica rice cultivars in the northern Jiangsu plain,China

In recent years,an increasing number of different types of japonica rice cultivars have been released in the southern rice region of China.The grain yield and quality of these new cultivars showed significant differences in large scale planting.However,the causes of the differences remain little known.Therefore,three typical types of japonica rice cultivars were used in this study to investigate their grain yield and quality.A scanning calorimeter(DSC),X-ray powder diffractometer(XRD),rapid viscosity analyzer(RVA)and taste analyzer were used to evaluate the cooking and eating properties.The results showed that the yield of non-soft hybrid japonica rice cultivars was significantly higher than that of non-soft inbred japonica rice cultivars and soft inbred japonica rice cultivars.Soft inbred japonica rice cultivars had a low amylose content and moderate protein content,which are the main reasons for the superior cooking and eating quality.In addition,the relative crystallinity of soft inbred japonica rice cultivars was significantly higher than that of non-soft inbred and non-soft hybrid japonica rice cultivars,which is considered the major factor resulting in higher transition temperature and gelatinization enthalpy(ΔH_(gel)).Non-soft hybrid japonica rice cultivars had a higher number of large starch granules than soft inbred and non-soft inbred japonica rice cultivars.The setback value(SB)and breakdown value(BD),indirectly reflecting the cooking and eating quality of the three types of japonica rice cultivars,also confirmed that soft inbred japonica rice cultivars with a low SB value and a high BD value had better palatability than the other two types.This study provides guidance for future plantation of different types of japonica rice cultivars in large rice-producing areas.

Thermal and textural properties of extruded rice affect its cooking performances and the texture of the steamed extruded rice

Extruded rice has increasingly gained popularity in the market due to its convenience and acceptable texture.The objective of this study was to understand how the physicochemical,thermal,and textural properties of the extruded rice affected its cooking properties and texture of the cooked one.It was found that air trapped in the grains during extrusion reduced the transparency of extruded rice.More air trapped in the grains reduced the true density of the extruded rice,which in turn decreased the hardness of extruded rice.A looser internal structure of extruded rice grain,as indicated by the lower true density,resulted in a faster hydration and shorter optimum cooking time.Extruded rices showed two thermal-transition peaks,with peak 1 from 93.3℃ to 112.8℃ and peak 2 from 107.5℃ to 132.5℃.The increased hardness of extruded rice led to increases in its thermaltransition temperatures,longer optimum steaming time,and decreases in its water absorption and cooking loss,which resulted in an increase in the hardness and a reduction in the adhesiveness of the steamed one.This study provides insights into the key factors determining the eating quality of extruded rice,which is beneficial for food scientists in developing premium extruded rice.

灌浆期田间自然低温对稻米蒸煮食味品质的影响

为研究灌浆期田间自然低温对不同水稻品种淀粉理化指标和稻米蒸煮食味品质的影响,选取7个高产优质水稻品种,分别加工成精米和米粉,测定在常温和低温下淀粉相关理化指标和米饭黏度、硬度及食味值。结果表明,水稻灌浆期遭遇低温会使稻米直链淀粉含量、消减值、峰值时间、糊化温度和米饭硬度显著升高,直链淀粉含量最大变幅达到47.4%;胶稠度、峰值黏度、崩解值和米饭黏度显著降低,其中胶稠度均降至30~50mm,最终导致稻米的蒸煮食味品质变差。利用食味值和淀粉理化指标对7个水稻品种进行低温耐受程度的综合评价,发现‘Y两优911’的稻米品质耐低温能力最强,‘Y两优1928’的稻米品质耐低温能力最弱。研究结果显示,在水稻灌浆期需采取适当的栽培措施应对低温对稻米品质造成的影响,为筛选培育耐低温优质稻提供了新思路。

电子束辐照对大米营养和蒸煮品质的影响

为进一步发展、完善辐照杀虫灭菌技术应用于储粮方面的理论研究,该研究采用0、0.83、1.56、2.30、4.93kGy不同剂量的电子束辐照大米样品,考察其对大米品质的影响。结果表明:不同剂量的电子束辐照对大米的蛋白质含量、氨基酸的含量与组成无明显影响(p>0.05);随着辐照剂量的增加,大米的脂肪酸值、胶稠度升高(p<0.05),吸水率、膨胀率下降(p<0.05);电子束辐照对大米糊化温度的影响不明显(p>0.05),但显著降低大米的峰值黏度、衰减值、回生值(p<0.05),明显影响米饭的蒸煮品质(p<0.05),剂量为4.93kGy时蒸煮米饭出现明显的褐变。电子束辐照大米的剂量不宜超过2.30kGy,以0.83kGy的辐照剂量较佳,该研究结果将为储藏和进出口检疫中对大米进行辐照杀虫、灭菌时的剂量选择提供参考。

不同类型水稻支链淀粉理化特性及其与米粉糊化特征的关系

目的探索稻米中支链淀粉理化特性及其与米粉的糊化特征的关系。方法以不同类型水稻代表性品种为材料,测定支链淀粉的蓝值和最大吸收波长,用SephadexG75层析柱分析支链淀粉分枝链的链长分配,并分析其与稻米RVA谱和米饭质地间的关系。结果不同类型代表品种的支链淀粉的蓝值和最大吸收波长存在显著差异,籼型品种稻米支链淀粉的蓝值和最大吸收波长要高于粳型(巴西陆稻除外),非糯性品种支链淀粉的蓝值和最大吸收波长呈极显著的线性关系(r=0.995)。经SephadexG75分离的FrⅠ部分的链长的平均聚合度>100glucoseunite,FrⅡ部分的链长的平均聚合度为44～47glucoseunite,FrⅢ部分的链长的平均聚合度为10～17glucoseunite。不同类型代表品种支链淀粉中长分枝链与短分枝链的比率存在明显的差异,在供试的糯性品种中,籼糯含长分枝链比粳糯多;非糯性品种中,籼稻比除粳型偏籼的巴西陆稻以外的粳稻含有更多的长分枝链。在同一类型品种中,供试的籼型杂交稻的支链淀粉中含有的长分枝链要比常规稻多,陆稻品种含的长的分枝链要高于水稻品种。支链淀粉的短链部分(FrⅢ)的比率与最高粘度和崩解值呈极显著的正相关关系(r=0.969,r=0.949),而长链部分(Fr(Ⅰ+Ⅱ))与最高粘度和崩解值呈极显著负相关关系(r=-0.969,r=-0.949)。结论水稻支链淀粉的分枝链长分配与稻米品质关系密切。在非糯性品种中,硬性和凝聚性大、松弛性和粘附性小的品种,米饭的口感表现硬,咀嚼有渣感,其Fr(Ⅰ+Ⅱ)比率大,即支链淀粉所含长分枝链比率高。

小米粉含量对小米小麦混合粉及其挂面品质特性的影响研究

将小米粉按照10％～80％的比例添加到小麦粉中,对小米小麦混合粉的粉质特性和糊化特性进行了分析,同时对由混合粉制作成的挂面的品质特性进行了分析研究.结果表明：1）随着小米粉添加量的增加,小米小麦混合粉的峰值黏度、最低黏度、最终黏度、回生值、衰减值和峰值时间都在降低,形成时间、稳定时间、粉质指数都是先降低再升高.2）挂面蒸煮损失率不断升高,干物质吸水率不断下降.小米添加量≤30％时,挂面品质比较好,添加量≤60％时,品质尚可,添加量＞60％时,挂面品质下降比较大.3）小米粉的添加量、小米小麦混合粉的RVA特性、粉质特性与混合粉挂面的蒸煮品质特性有非常高的相关性.

不同包装方式对大米储藏品质及挥发性成分的影响

【目的】通过测定不同包装方式大米储藏过程中食用品质(质构品质、糊化特性)以及挥发性成分,判断大米品质的变化,为小包装(规格为10 cm×18 cm)大米保鲜技术提供数据支持和理论依据。【方法】以‘粳稻99号’为材料,将大米采用编织袋包装、自然密闭缺氧包装及抽真空包装3种方式,分别置于15℃、25℃和30℃(60%湿度)的环境下储藏180 d。每月对其食用品质和挥发性成分进行分析。【结果】随着储藏时间的延长,蒸煮米饭弹性、回复性逐渐下降,硬度、黏着性呈现先上升后下降的趋势,且各项指标变化幅度较大。3种包装方式下大米消减值随储藏时间延长逐渐增大,崩解值呈现先增大后减小的趋势,大米热糊稳定性变差,容易老化。新鲜大米中挥发性成分共鉴定出41种,主要包括烃类、醇类、醛类、酮类、酯类、有机酸类以及杂环类化合物等。醛类含量可以用来评价大米的食味和鲜度,储藏180 d后,编织袋包装的大米含量最高,占挥发性成分20%以上,自然密闭缺氧包装次之,抽真空包装醛类物质最少。2-戊基呋喃是亚油酸氧化产物,新鲜大米中2-戊基呋喃含量仅为0.30%,随着储藏时间延长,编织袋包装的大米2-戊基呋喃含量急剧上升。醛类及2-戊基呋喃含量受包装方式影响较大,3种包装方式对大米储藏保鲜效果的排序为:抽真空>自然密闭缺氧>编织袋,然而当储藏温度过高时,即使采用抽真空包装,大米储藏品质也发生了劣变。3种包装方式下2-戊基-呋喃每个时期均被检测出,编织袋、自然密闭缺氧、抽真空3种包装方式己醛含量分别为1.82%、1.55%、1.16%,壬醛含量分别为4.7%、3.94%、2.77%,2-戊基-呋喃含量分别为2.27%、1.85%、1.43%,由此可以推断编织袋包装的大米产生较明显的油脂氧化的异味,陈化最为严重,自然密闭缺氧次之,抽真空能有效延缓大米品质陈化的速率。【结论】大米储藏过程中的硬度、弹性、黏着性、回复性以及糊化特性均不及新鲜大米。抽真空包装有益于大米储藏,可有效延缓大米劣变。醛类含量可以用来评价大米的食味和鲜度,储藏180 d后,3种包装方式中醛类含量皆有增长,以编织袋包装的醛类含量增长最为明显。大米挥发性成分中的醛类物质中,己醛、壬醛和2-戊基-呋喃可以较好地反映大米的储藏品质。

蒸制对冷冻荞麦熟面品质的影响研究

为了改善冷冻荞麦熟面的品质特性,采用汽蒸的方式对其进行预处理,研究蒸面预处理对冷冻荞麦熟面品质(面条吸水率、蒸煮损失及质构特性)的影响。同时采用快速黏度分析仪(RVA)和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)分析蒸面预处理对面条的糊化特性及蛋白质亚基结构的影响。结果表明,汽蒸处理能显著降低面条的蒸煮损失,提高其复热后的硬度、弹性和咀嚼性,并且蒸制3 min时,其总蒸煮损失达到最小值。RVA分析表明,随着汽蒸时间的增加,淀粉的崩解值和峰值黏度降低,而糊化温度增加。SDS-PAGE图谱显示,随着蒸面时间的延长,低分子质量亚基条带的颜色变浅,说明汽蒸可能诱导其发生了交联聚合行为。因此,蒸面预处理可以提高面条的蒸煮特性和质构特性,改善冷冻荞麦熟面的品质特性。

播期和收获期对丰两优1号米饭食味品质的影响

通过杂交中籼丰两优1号组合的分期播种和收获试验,分析了播期和收获期对其稻米直链淀粉、蛋白质含量、米饭质地和食味感官评价值的影响以及上述诸性状在不同播期和收获期的变异系数,并对水稻灌浆结实期若干气候因子与稻米主要品质性状进行偏相关分析。结果表明:5个性状即蛋白质含量、米饭质地的硬度和弹性以及米饭食味感官评价中滋味和弹性在不同播期和收获期均存在显著或极显著差异。根据稻米品质性状在不同播期和收获期变异系数的大小大致分为3类,其中咀嚼性的变异最大;弹性、胶性和凝聚性居中;其它性状较小。在影响稻米品质的气候因子中,水稻灌浆结实期日均气温的作用较大。丰两优1号组合在温州地区可选择6月15日左右播种,灌浆结实期的平均气温约22.0℃,并适当推延收获期将会取得最佳品质效应。丰两优1号的直链淀粉含量约16%、蛋白质含量约9.0%、质地弹性约1.3、咀嚼性大于400 g,米饭食味品质较优。

不同储藏年限稻谷的品质及鲜湿米粉加工适应性分析

目的:了解不同储藏年限的稻谷加工鲜湿米粉后的品质变化,为鲜湿米粉加工原料的选择提供依据。方法:选用不同储藏年限的籼稻、粳稻各40份,将其加工成鲜湿米粉,通过测定鲜湿米粉的蒸煮损失率、断条率、感官评分与质构等指标,并用描述统计分析、方差分析和主成分分析、聚类分析等方法探究两种稻谷的加工品质。结果:随着原料储藏年限的延长,籼型米粉的蒸煮损失率呈逐渐降低的趋势,粳型米粉呈先下降后上升的趋势;两种类型米粉的断条率均是呈先降低后升高的趋势;两种米粉的色泽、气味得分均呈降低趋势,外观结构、筋道感、爽滑感得分和感官总分均呈先升高后降低的趋势,且籼型米粉的感官品质好于粳型米粉;两种米粉的硬度、咀嚼性呈上升趋势,且均在储藏年限为4年时达到显著性水平(P<0.05),黏着性也呈上升趋势,其他质构指标无明显变化;通过聚类分析得出品质分类情况,并统计各储藏年限的样品数,发现籼稻加工鲜湿米粉适应性好于粳稻,且储藏3年时的籼稻加工鲜湿米粉的品质较好。

中国食用优质米品质的分析研究

研究了中国24个省、市、自治区选送的98个优质米代表品种的品质。并根据农业部优质米标准,对不同稻类、不同栽培季节的优质米品种的品质性状进行了比较。分析了稻米品种性状间的相关性。讨论了中国稻米品质改良的重点、途径及优质米标准多样化的问题。

汤圆粉团制作方法比较及其对蒸煮品质的影响

为了探索汤圆粉团制作方法对其蒸煮品质的影响,以水磨糯米粉为原料,采用3种典型汤圆粉团制作方法制作汤圆粉团,并对其外观品质、蒸煮后的透光度、感官评价以及其粉团TPA物性进行测定与分析。结果表明,汤圆粉团蒸煮品质受制作方法的影响明显。冷水调粉法制作的速冻汤圆粉团的蒸煮品质明显优于热烫法和煮芡法,而对于鲜汤圆粉团的制作,热烫法制作的汤圆粉团优于煮芡法和冷水法。

大豆蒸煮时间对黄豆酱发酵过程中理化特性的影响

研究了不同蒸煮时间（5、8、10、15min）对黄豆酱发酵过程理化指标和感官特性的影响，分析不同黄豆酱的总氮（酱醪除外）、氨基酸态氮、可瘩性氮含量的动态变化，豆粒硬度变化以及产品感官品质。结果表明，黄豆酱发酵前期（1～30d），总氮、氨基酸态氮、水溶性氮含量均随培养时间的延长呈上升趋势，之后基夺保持动态平衡或稍有变化。蒸煮时间对黄豆酱各指标的影响有显著性差异（P〈0．05），其中对酱醪的影响尤为显著。蒸煮时间对豆粒的硬度影响比较大，莲煮时间越长，豆粒硬度越小。发酵至30d时，蒸煮15min黄豆酱中豆粒破坏严重。对四种不同产品进行感官评价，发现蒸煮8min黄豆酱产品无论在色泽、香气、滋味和体态各方面较好，总体得分最高。

添加甘薯淀粉对面条品质的影响

利用重组的方法,通过向小麦面粉中添加甘薯淀粉,配成淀粉含量范围超出原小麦粉的系列混合粉,制作典型的中国机制的鲜湿面条,测试了重组粉的糊化特性和面条的蒸煮品质,探讨了甘薯淀粉添加量和面粉糊化特性及面条蒸煮品质的关系.结果表明:随着甘薯淀粉添加量的逐渐增大,混合粉的粘度增加,糊化温度降低;面条的干物质吸水率增加,干物质损失率和蛋白质损失率先减小后增加.