粳性和糯性糜子淀粉的理化性质

为揭示粳性、糯性糜子淀粉的理化特性及其差异,本文选用2个粳性糜子、2个糯性糜子品种为试验材料,以玉米淀粉、马铃薯淀粉为对照,研究比较了其淀粉的颗粒形态与大小、晶体结构、直链淀粉含量、透明度、冻融稳定性等理化性质。结果表明：粳性、糯性糜子淀粉颗粒形态均呈棱角圆滑的多面体形或球形,平均粒径分别为7.18 μm、6.04 μm,结晶构型均为A型;粳性糜子淀粉直链淀粉含量、冻融析水率高于糯性糜子淀粉,而透光率较低;粳性、糯性糜子淀粉的溶解度与膨胀度均随温度升高而增大,前者的溶解度、膨胀度较低;粳性糜子淀粉破损值低,热糊稳定性好,而糯性糜子淀粉的回生值低,冷糊稳定性好。因此,糜子淀粉可作为一种新型的淀粉资源应用于不同领域。     

粳性和糯性糜子淀粉的理化性质

为揭示粳性、糯性糜子淀粉的理化特性及其差异,选用2个粳性糜子、2个糯性糜子品种为试验材料,以玉米淀粉、马铃薯淀粉为对照,比较了其淀粉的颗粒形态与大小、晶体结构、直链淀粉含量、透明度、冻融稳定性等理化性质。结果表明,粳性、糯性糜子淀粉颗粒形态均呈棱角圆滑的多面体形或球形,平均粒径分别为7.18、6.04μm,结晶构型均为A型;粳性糜子淀粉直链淀粉含量、冻融析水率高于糯性糜子淀粉,而透光率较低;粳性、糯性糜子淀粉的溶解度与膨胀度均随温度升高而增大,前者的溶解度、膨胀度较低;粳性糜子淀粉破损值低,热糊稳定性好,而糯性糜子淀粉的回生值低,冷糊稳定性好。因此,糜子淀粉可作为一种新型的淀粉资源应用于不同领域。     

蕨麻淀粉特性的分析

测定了蕨麻淀粉的水分含量、白度、直链淀粉含量等,分析了溶解度、膨胀度、透光率等溶胀特性,并对峰值粘度、谷粘度、崩溃值等糊化特性和硬度、粘附性、弹性、咀嚼性等凝胶特性进行了研究。结果表明,蕨麻淀粉中的水分含量为10.95%,直链淀粉含量27.93%,白度为77.38%。溶解度和膨胀度分别为22.07%和44.58%,透光率7.51%。蕨麻淀粉有较好的糊化特性,但冷糊的稳定性较差,易老化;蕨麻淀粉糊化后形成的凝胶硬度和弹性较低,粘附性很高。     

糜子直链淀粉、蛋白质含量对其外观品质及食味品质的影响

以4个直链淀粉、蛋白质含量存在显著差异的糜子品种为实验材料,研究直链淀粉、蛋白质含量对糜子外观及食味品质的影响。结果表明：与低直链淀粉品种比较,高直链淀粉糜子品种,全粉糊化黏度、糊化时间、糊化温度较高,糜子饭吸水率、体积膨胀率、硬度较高,而糊化热焓值较低;蛋白质含量较高的糜子品种,全粉呈现低糊化黏度,糜子饭呈现低吸水率、体积膨胀率,高硬度。直链淀粉、蛋白质含量较高的糜子品种,蒸煮性差、能耗高、蒸煮时间长。因此,在糜子品质育种中,适当降低直链淀粉和蛋白质含量可以改善糜子的适口性。     

大米粉特性与大米面包感官及质构特性关系的研究

探讨了7种大米粉(软米、香糯1号、辽河五、千米糯、辽粳294、371、稻花香)的特性与大米面包品质的关系,并分别建立了大米面包品质各指标与直链淀粉含量、淀粉的溶解度和膨胀度之间的回归模型。大米面包是由经预糊化的大米粉和小麦粉混合后,采用一次发酵法制成,其中大米粉的添加量为20%。结果表明:香糯1号和软米在一定程度上提高了面包的比容积,是最适宜制作大米面包的大米品种;大米的直链淀粉含量对大米面包品质影响最大(r=0.546 3);直链淀粉含量、淀粉的溶解度和膨胀度3个因素对大米面包的比容积、硬度、负载、弹性、咀嚼性和感官评价方面有一定的影响。     

不同品种绿豆淀粉的功能特性比较研究

以9个品种绿豆淀粉为研究对象,研究了绿豆淀粉的化学组成及糊化特性、溶解度、膨胀度和冻融稳定性等功能特性,并分析了直链淀粉含量与功能特性的相关性。结果表明,不同品种绿豆淀粉直链淀粉含量不同,其分布范围为33.10%~44.08%;不同品种淀粉糊化特性参数间有明显差异;潍绿4号和中绿1号绿豆淀粉峰值粘度显著高于其他品种(p0.05),安绿8号具有最低破损值(p0.05),毛绿豆和安绿092具有较低的回生值。绿豆淀粉的溶解度和膨胀度与温度有关,均随温度的增加而增大。不同品种绿豆淀粉糊经一次冻融后析水率均较高,随冻融循环次数的增加,析水率均逐渐增大。相关性分析表明,直链淀粉含量与淀粉糊的最终粘度和回生值之间存在显著正相关(r=0.674,r=0.725;p0.05),与膨胀度之间具有极显著负相关关系(r=-0.805,p0.01)。     

紫糯麦淀粉理化特性研究

以紫糯麦168为原料提取紫糯麦淀粉。对其理化特性研究表明:紫糯麦淀粉有较低的直链淀粉含量和较高的相对结晶度,呈现典型的A型结晶特征;紫糯麦淀粉糊的透明度为22.57%,膨胀度和溶解度随温度的升高均增大;在贮藏期间上清液体积增加缓慢;经2次冻融循环后表现出较好的冻融稳定性;紫糯麦淀粉糊有高的峰值黏度和崩解值,较低的回生值和糊化温度。     

我国不同地区特色品种小米淀粉性质

选取10 个不同地区、品种的特色小米作为研究对象,采用0.2 g/100 mL的NaOH溶液与1 g/100 mL的十二烷基硫酸钠溶液复合法提取小米淀粉,并对其基本成分、颗粒形态、黏度、透光率、溶解度和膨胀度等进行研究。结果表明：小米淀粉的直链淀粉含量为12.10%,平均粒径为6.49 μm,糊化温度为68.9～72.3 ℃。不同地区、品种的小米淀粉的直链淀粉、溶解度、峰值黏度、崩解值和老化值存在较大差异。     

黄米品质特性研究

以四种不同的糜子为原料,脱去皮壳后得到黄米,对其理化特性、蒸煮特性和糊化特性进行分析。结果表明,四种黄米的碳水化合物、粗蛋白、粗脂肪、粗纤维和灰分平均含量分别为77.5%,10.1%,1.9%,2.1%和0.9%,蛋白质、粗纤维含量较高,矿物元素以K、Mg和Ca为主;黄米溶解度和膨胀度随着温度升高而增加;黄米在20 min内吸水达到饱和,具有良好的蒸煮品质;抗性淀粉含量低,蒸煮后四种黄米的RS含量均明显增加;四种黄米粉的起糊温度、峰值黏度、破损值、最终黏度和回生值平均为63.9℃,720.3 RVU,192.3 RVU,824.0 RVU和296.0 RVU。不同品种黄米粉间的糊化特性存在差异。     

酶辅助碱法提取龙眼核淀粉的结构与理化性质研究

目的:明确酶辅助碱法提取的龙眼核淀粉的结构及理化性质。方法:以龙眼核为原料,碱性蛋白酶为酶解剂提取龙眼核淀粉,研究了其化学组成、粒径、微观形貌、晶体结构、透明度、溶解度及膨润力、热力学特性及糊化特性等。结果:100 g龙眼核淀粉中含有82.64 g淀粉、0.68 g粗脂肪、0.46 g粗蛋白和1.06 g灰分,其直链淀粉含量为36.37%;其颗粒多呈椭圆形或不规则多边形,平均粒径为11.21 μm,结晶结构为A型,近程有序程度较高;1%（w/v）龙眼核淀粉糊的透光率为4%;溶解度和膨润力均随温度上升而增大,90 ℃时分别为11.26%和15.93%;龙眼核淀粉具有较高的糊化起始温度（70.4 ℃）、峰值温度（75.9 ℃）、结束温度（82.1 ℃）和糊化焓（13.7 J/g）,其热糊稳定性较差,冷糊稳定性较好。结论:酶辅助碱法提取的龙眼核淀粉直链淀粉含量高,蛋白质含量下降明显,颗粒小,不易糊化。     

Structural and Physical Properties of Starches Isolated from Six Varieties of Millet Grown in China

This study investigated the structural and physical properties of starches extracted from six varieties of millet mainly grown in China. The amylose content of millet starches ranged from 17.6 to 28.4 g/100 g (dry weight basis, db), and a variety of waxy proso millet starch (0.38 g/100 g, db) was identified. These starches exhibited a majority of large polygonal granules with several indentations, few small spherical granules, and A-type crystallinity. Proso millet starch showed prominent paste clarity and freeze-thaw stability, whereas finger millet starch exhibited the highest solubility. Moreover, barnyard millet starch had the lowest sediment volume. The gelatinization enthalpy of proso millet starch was the highest (5.16 J/g). For non-waxy millet starch, the ratio of retrogradation (R%) was positively correlated with amylose content. Among all starches, the storage modulus (G′) was higher than the loss modulus (G″) during heating and cooling. The G′ and G″ of proso millet starch and barnyard millet starch pastes were significantly lower than other starches during cooling. The pasting properties of six millet starches significantly differed, had positive correlation with amylose content, and were affected by NaCl, sucrose, and pH values.     

基于主成分分析的21种粳性黄米品质评价

目的:对不同粳性黄米品种的品质进行评价。方法:以21个粳性黄米品种为试验材料,测定其营养成分、糊化特性、蒸煮特性及质构特性,分析品质差异及指标相关性,运用主成分分析进行综合评价。结果:质构特性、粗脂肪含量、回生值、破损值、最终黏度在品种间差异较大,起糊温度和淀粉含量的变异系数较小,是较为稳定的指标。主成分分析结果显示前3个主成分反映了原变量72.04%的信息,筛选出最终黏度、回生值、硬度和黏附性为关键指标,根据综合得分评价出粳性黄米品种的综合品质优劣。结论:陇糜10号、内糜9号、陇糜8号、榆糜3号、宁糜13号的综合品质最优,最终黏度、回生值、硬度和黏附性可作为粳性黄米品质的代表性指标,用于指导黄米品种筛选。     

不同品种小米淀粉品质特性研究

选取山东农科院提供4种小米(济12、济13、保18、复1)及山东省部分地区种植2种小米(市1、市2)作为研究对象,采用1%SDS法提取小米淀粉,对不同品种小米淀粉直链淀粉含量、可溶直链淀粉含量、凝沉性、膨润性、溶解度等进行研究,并对淀粉理化指标进行相关性分析。结果显示,不同品种小米直链淀粉含量为2.27%~31.98%,其中以市1品种含量最高;复1和市2膨润力和溶解度最大;凝沉性排列次序为:高直链小米淀粉(市1)>中直链小米淀粉(济12、济13、保18)>低直链小米淀粉(复1、市2);淀粉理化指标间进行相关性分析结论为:溶解度、膨润力、凝沉体积皆与直链淀粉含量呈显著负相关。     

糯小米和大黄米的餐后血糖反应和饱腹感评价

为了研究糯性杂粮的餐后生理反应,选择糯小米和糯大黄米为研究对象,以非糯性的普通小米作为对照,测定三种样品在鲜热、冷藏、回热之后的人体餐后血糖反应和饱腹感反应,计算血糖生成指数(GI)与饱腹感指数(SI)。参比食物为葡萄糖和粳米饭。结果表明,新鲜烹调的糯小米和大黄米样品GI值分别为108和111,冷藏和回热样品的GI值也与参比葡萄糖相当,远高于各处理小米和参比食物粳米。回热大黄米的SI显著高于其他样品。因此,糯小米和大黄米尽管为全谷食物,但仍属高血糖反应食物,且冷藏处理不能有效降低其餐后血糖反应。     

几种糯性食物的淀粉消化特性

为了研究糯性食物的消化特性,选择大米(Oryza sativa L.)、小米(Setaria italica L.)、大黄米(Panicum miliaceumL.)相对应的糯性和非糯性品种进行体外模拟消化实验,测定鲜热、回热、冷藏样品的体外消化速度,并测定市售糯米制品的淀粉组分。结果表明：糯性品种消化速度显著高于非糯性品种,但粗杂粮的糯性品种消化速度仍然略低于精白大米;圆粒糯米与长粒糯米在冷藏后有明显差异;对于糯性品种来说,再次加热时的消化速度可能比新鲜烹调时更高;糯米加工食品均属于高消化速度食品。结论：无论新鲜烹调或冷藏,糯性淀粉食物消化速度均较快,需要控制血糖者和控制体质量者应谨慎食用。     

湿热处理对糜子粉及淀粉理化性质的影响

采用糜子粉及糜子淀粉作为试验材料,研究湿热处理对不同含水量（20%-35%）样品颗粒形态、晶体结构、成糊特性、热力学特性、膨胀度、透明度等理化性质的影响。结果表明,改性后的样品颗粒发生了局部糊化,表面变得凹凸不平,晶体类型仍为A型结构,但结晶度增加。湿热改性的糜子粉及淀粉的起糊温度显著提高,峰值黏度、低谷黏度、破损值及热焓值降低,膨胀度和透明度随水分含量的升高而降低。这些现象说明湿热处理能够改变糜子粉及其淀粉的理化性质,为其扩大应用范围提供一定的指导。     

糜黍淀粉理化性质及消化特性

以黍子面和糜子面为原料,用碱法制备黍子淀粉和糜子淀粉,对其颗粒形态、红外光谱特性、透光率、溶解度、持水力、凝沉稳定性以及消化性等性质进行研究。结果表明：黍子淀粉中支链淀粉含量为91.78%,直链淀粉含量为8.21%;糜子淀粉中支链淀粉含量为65.28%,直链淀粉含量为34.72%。糜子面粉、黍子面粉及其淀粉中的抗性淀粉含量均超过50%,糜子面和糜子淀粉中的抗性淀粉含量均分别高于黍子面和黍子淀粉。黍子淀粉的透光率高于糜子淀粉。糜子淀粉凝沉稳定性强于黍子淀粉。糜子淀粉和黍子淀粉的溶解度、持水力随温度的升高,呈现上升趋势。     

Physicochemical,Textural, Pasting,and In Vitro Digestion Properties of Some Basmati and Non-Basmati Rice Cultivars

Grain quality attribute tests based on physicochemical, textural, pasting, and in vitro digestion properties of eight different rice cultivars were studied. Basmati varieties showed higher values of amylose content, iodine absorption, blue value, hardness, cohesiveness, pasting temperature, and set back, whereas swelling power, solubility, adhesiveness, peak viscosity, and breakdown values were found to be higher in non-basmati varieties. The release of maltose from basmati rice flour (23.12–25.86 mg/g rice flour) was found to be slower as compared to non-basmati ones (27.43–28.36 mg/g rice flour). Amylose content showed significant correlations with different quality parameters at 5% level of significance.     

Isolation and Characterization of Starch from Pearl Millet (Pennisetum typhoidium) Flours

Pearl millet, an underutilized crop, is a relatively good source of nutrients and has varied uses over cereals. New applications must be explored to popularize the millet. In the present study, flour and isolated starch from pearl millet cultivars—Kalukombu and Maharashtra Rabi Bajra (MRB)—were investigated for physicochemical properties, nutritionally important starch fractions and x-ray diffraction. The yield of starch was significantly low (Kalukombu: 34.5 g/100 g and MRB: 39.4 g/100 g) with traces of non-starch components (protein, fat, and ash) indicating its purity. Starch could be classified as non-waxy type based on low amylose content (2.86–4.96 g/100 g). Low amylose lead to fragility of swollen starch granules which disintegrated easily at 65°C as observed in swelling power and solubility. Isolated starch was characterized with low water- and oil-holding capacity which could be attributed to the low protein content and absence of fiber in the starch. However, MRB starch showed higher oil uptake compared to flour, possibly due to its larger surface area that increased oil uptake. X-ray diffraction patterns showed sharp peaks at 2θ values 15 and 23º and a diffused peak at 2θ of 17 and 18º which is characteristic of A-type pattern. Low resistant starch (RS) and high readily digestible starch (RDS) content observed in the isolated starch could be attributed to the A-type pattern of starch which is more susceptible to enzyme hydrolysis and also due to elimination of structural obstruction to amylase hydrolysis during the process of starch isolation and gelatinization.