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。     

脱除不同溶解性内源蛋白质对早籼米粉理化性质的影响

为通过利用内源蛋白质调控早籼米粉理化性质提高其制品品质，本文研究脱除不同溶解性内源蛋白质（清蛋白、球蛋白、醇溶蛋白和谷蛋白）对早籼米粉溶解度、膨胀度、成糊特性及其糊化后水分结合状态、流变学特性和冻融稳定性的影响。结果表明，脱除球蛋白和谷蛋白可提高早籼米粉的溶解度，而脱除醇溶蛋白和谷蛋白均可在高温下提高其膨胀度。脱除清蛋白使早籼米粉成糊的峰值粘度、终值粘度、崩解值和回生值分别降低16%、21%、50%和43%；脱除球蛋白可提高其糊化温度并降低其峰值粘度，脱除醇溶蛋白则相反；脱除谷蛋白使其峰值粘度和终值粘度分别降低22%和12%，并使其崩解值和回生值分别提高49%和53%。脱除谷蛋白使早籼米粉糊化后的弱结合水含量降低14%；脱除球蛋白和谷蛋白均可提高其糊化后与水结合的强度，脱除醇溶蛋白则相反。脱除醇溶蛋白使早籼米粉糊化后的似固状态增强20%；脱除球蛋白和谷蛋白均可降低其糊化后的弹性，脱除醇溶蛋白则相反。脱除球蛋白和谷蛋白使早籼米粉糊化后的冻融稳定性分别降低121%和56%。该研究工作为利用不同溶解性内源蛋白质提高早籼米粉制品品质提供了重要的参考依据。     

大米蛋白对大米粉糊化性质的影响

以DOM为20％的晚籼米为材料,通过利用差示扫描量热分析仪(DSC)、快速粘度测定仪(RVA)和环境扫描电镜(SEM)和测定润胀性和溶解性等方法,对添加不同梯度大米蛋白后的米粉样品的润胀性和溶解性、DSC热谱、RVA图谱和形态进行比较分析 结果表明,添加一定梯度的大米蛋白后,米粉样品的润胀性和溶解性、峰值粘度、低谷粘度、崩解值和终值粘度逐渐降低,糊化温度、回生值、峰值时间和热焓值(△Hr)增加,大米蛋白与淀粉呈现出网状结构,表明大米蛋白能与淀粉发生相互作用,形成网状结构,实验结果说明,大米蛋白对大米淀粉的糊化和膨胀过程起着抑制作用.     

籼米黄淀粉中蛋白质的功能性质

以分别经中性蛋白酶和二硫苏糖醇(DTT)处理的籼米黄淀粉或灿米黄淀粉蛋白样品为对照,对籼米黄淀粉中蛋白质的形态结构、功能性质及其对黄淀粉糊化性质的影响进行了研究。结果表明,籼米黄淀粉中的蛋白质是以小蛋白体的形式结合在纤维素上面,并与淀粉相互作用,共同影响黄淀粉蛋白的功能性质;蛋白酶与二硫苏糖醇对这种结构能造成一定的破坏;籼米黄淀粉蛋白分子结构中存在相当数量的二硫键,且二硫键遭受破坏的程度、蛋白分子中肽片段的多少以及分子间相互作用的强度同样影响到籼米黄淀粉蛋白的各种功能性质。     

快速粘度仪在燕麦粉理化性质研究上的应用

燕麦粉作为一种谷物,加工后可广泛应用于饮料体系。本文应用快速粘度仪(RVA)主要研究了燕麦粉的淀粉糊化特性,同时,通过面筋蛋白醇溶指数法及稀乳酸法,分别研究了燕麦粉的面筋蛋白质质量特性。探讨了不同工艺条件对淀粉糊化特性及面筋蛋白质粘度特性的影响,同时,测定了燕麦粉中β-葡聚糖的含量,实验表明其在燕麦粉的RVA稀乳酸法面筋蛋白质粘度特性的测定中无明显影响。另外,稀乳酸法中峰值粘度及最终粘度,与醇溶指数法中最终粘度间分别存在相关性,而与醇溶指数法中醇溶指数间无相关性。     

糯小麦粉与普通小麦粉配粉糊化特性的研究

选用糯小麦品种中糯一号与普通小麦(非全糯小麦)品种豫麦47、温6和澳大利亚优质面条小麦品种Gamenya,进行籽粒蛋白质含量、淀粉含量及直链淀粉含量的测定。并将中糯一号面粉分别与豫麦47、温6面粉配粉,进行了RVA试验(快速粘度分析),研究了三种单一品种面粉及其配粉的糊化特性。结果表明:中糯一号籽粒蛋白质含量、淀粉含量与供试普通小麦品种相近。但其直链淀粉含量很低,仅为1. 45%,远低于供试普通小麦品种。在RVA试验中,中糯一号面粉糊化快,峰值时间比普通小麦缩短了一半,其粘度下降到低谷后,粘度曲线变化平缓,回冷值很小,明显与供试普通小麦不同。糯小麦与普通小麦配粉的粘度曲线呈双峰状,其粘度参数因糯、普小麦配粉比例不同而不同。总之,在普通小麦粉中加入糯小麦粉后,面粉直链淀粉含量和糊化特性发生了变化,对面制食品品质将产生一定的影响。     

豆渣膳食纤维对不同面粉糊特性、热力学性质及面团质构的影响

本论文通过RVA、DSC和TPA分析了添加豆渣膳食纤维后不同面粉的性质,RVA结果分析表明,添加少量豆渣膳食纤维可使高筋粉和中筋粉糊化参数略有增加,而添加量增加到一定程度时,由于体系中淀粉分子数量减少,使面粉的粘度参数降低。DSC结果分析表明,豆渣膳食纤维的添加可以增大高筋粉和低筋粉的糊化温度,降低中筋粉的糊化温度,并且由于淀粉含量的减少,使三种面粉的糊化焓值均降低。TPA结果分析表明,添加一定量膳食纤维对高筋粉和低筋粉面团品质在一定程度上有损害,而对中筋粉面团胶着性、弹性、粘性和回复性方面有一定改善作用。     

籼米为基质的脂肪替代品--糊化工艺研究

本文利用差示扫描量热仪（DSC）法研究了籼米的蛋白质对淀粉糊化的影响，着重研究了籼米为了基质的脂肪替代品加工过程中的糊化工艺。研究结果表明：在籼米淀粉中添加米蛋白其糊化温度基本不变，但糊化所需热量下降。籼米的最佳糊化条件为米粉粒度100目，糊化温度88℃，糊化时间1h。     

大米淀粉制备工艺对其糊化特性和粒度分布的影响

以籼米和粳米为原料,大米淀粉糊化特性和粒度分布作为评价手段,比较了碱法、中性蛋白酶法、碱性蛋白酶法(pH=8、pH=10)4种制备大米淀粉的工艺。结果表明,碱法制备的大米淀粉蛋白质残存率显著低于酶法,而3种酶法蛋白质去除率一致,但碱法部分破坏了淀粉颗粒的天然结构;经RVA糊化曲线分析,采用碱性蛋白酶法(反应条件pH=10)、中性蛋白酶法得到的籼米淀粉以及采用中性蛋白酶法得到的粳米淀粉能较好地保持天然淀粉的糊化特性;通过粒径分布检测,确定采用中性蛋白酶法处理粳米能制备得到粒径分布均匀的大米淀粉。综合各个评价指标,以粳米为原料,采用中性蛋白酶法可得到淀粉破坏小、粒径分布均匀、蛋白质残留率低的大米淀粉。     

糯小麦“山农糯麦1号”籽粒及淀粉品质分析

为更好地了解糯小麦的品种特性,以山东省第一个审定的高产糯小麦“山农糯麦1号”为材料,研究其籽粒和淀粉特性。结果发现：该品种几乎不含直链淀粉（仅0.1%）,较普通小麦具有较高的蛋白质含量（16.4%）和面粉白度（81.2%）。扫描电镜观察淀粉粒度分布不均匀,A型淀粉颗粒较多。快速粘度分析（RVA）测定表明淀粉具有较低的糊化温度,较短的糊化时间,较低的峰值黏度、最终粘度和回生值。加工时面团吸水率明显较高,形成时间大于稳定时间。这些结果将为山农糯麦1号适于用作配粉和加工食品提供参考依据。     

大米粉、大米淀粉及其磷酸酯淀粉的物性特征研究

利用快速黏度分析仪和质构仪测定了大米粉、大米淀粉及其磷酸酯淀粉的黏滞特性和质构特性,并用动态流变仪测定了大米粉、大米淀粉和磷酸酯淀粉糊的凝胶和回生。结果显示:磷酸酯淀粉的糊化温度显著低于大米粉和大米淀粉的糊化温度;磷酸酯淀粉抗老化性最强,不易回生,大米粉抗老化性最弱,易回生。大米淀粉经过磷酸酯化变性后,峰值黏度、崩解值和最终黏度增加,硬度、黏附性、弹性、胶黏性显著降低,凝聚性增强。在降温冷却过程中,大米粉的储存模量比大米淀粉和磷酸酯淀粉的储存模量增长速度快,大米粉和大米淀粉的损失因数降低,磷酸酯淀粉的损失因数升高。     

两种大米淀粉及其磷酸酯淀粉理化特性的比较研究

对比分析2种大米(籼米和粳米)的全粉、淀粉和取代度均为0.068的磷酸酯淀粉的理化特性.粳米的全粉、淀粉和磷酸酯淀粉的膨胀力分别为7.5,10.7,21.6 g/g,分别高于籼米的全粉、淀粉和磷酸酯淀粉的膨胀力(5.8,8.9,17.4 g/g).2种大米淀粉经磷酸酯化后透光率增高,相应淀粉的透光率次之,全粉的透光率最低,籼米的全粉、淀粉和磷酸酯淀粉的透光率分别低于粳米的全粉、淀粉和磷酸酯淀粉的透光率.经快速黏度分析仪测定的糊化特性结果表明,淀粉或变性淀粉膨胀力高,其峰值黏度和崩解值也高,此外,蛋白质含量和直链淀粉含量也极大的影响了淀粉的糊化特性.使用动态流变仪测定的流变特性表明,在相同的温度下,籼米的全粉、淀粉和变性淀粉的储能模量(G')分别比粳米的全粉、淀粉和变性淀粉的储能模量(G')高,对于相同的大米品种,全粉的储能模量(G')最高,变性淀粉的储能模量(G')最低.     

Genetic diversity in the physicochemical properties of waxy rice (Oryza sativa L) starch

The genetic diversity in the physicochemical properties of starches from 56 waxy rice (Oryza sativa L) genotypes (34 of indica and 22 of japonica) was studied. The parameters included thermal and retrogradation properties tested by differential scanning calorimetry (DSC), pasting viscosity tested by rapid viscoanalyser (RVA), and flour swelling volume (FSV). Wide diversity was found in all the parameters. According to their gelatinisation temperature (GT), the waxy rice genotypes could be divided into two groups, a high‐GT group and a low‐GT group. A total of 15 genotypes were identified as high‐GT, all belonging to the indica subspecies. There was about a 5 °C difference within each group and a 10 °C difference between groups. Many parameters were correlated with each other in all 56 waxy rices, but some correlations were also consistent and significant when comparing the high‐GT group and the low‐GT group separately. For example, hot paste viscosity (HPV) was positively correlated with onset temperature (T_o) and enthalpy of gelatinisation (ΔH_g). The results suggested that initial screening in waxy rice breeding programmes for varieties with desirable starch properties for specific food uses could be efficiently accomplished using pasting profiles from the RVA. Copyright © 2004 Society of Chemical Industry     

Pasting Properties of Ohmically Heated Rice Starch and Rice Flours

ABSTRACT:  Pasting characteristics were examined for conventionally or ohmically heated rice starch and rice flours. Brown rice flour showed the greatest cooking stability and least retrogradation potential. Brown rice flour also showed the greatest pasting temperature and lowest peak viscosity, whereas commercial starch had the lowest pasting temperature. Nonstarch components of the brown rice flour, such as fat and protein, may have acted as stabilizers delaying water access into the granules and reducing swelling of the starch. Ohmic heating reduced pasting temperature for commercial rice starch, resulting in a starch that swelled faster. Furthermore, ohmic heating produced better cooking stability in white rice flour 1 and 2 than in the native sample, and caused white rice flour 2 to have less potential for retrogradation than the conventionally heated sample. At lower electric field strength (20 V/cm), ohmic heating resulted in the greatest cooking stable starches compared to higher voltages (40 and 70 V/cm) because more starch granules were disrupted from a longer cooking time, so there were fewer intact granules for pasting. Ohmic heating has been shown to alter rice starch and flour pasting characteristics with an added influence of lipids, proteins, and amylose contents.     

大米蛋白对小麦淀粉理化特性的影响

以小麦淀粉为原料,利用差示扫描量热仪(DSC)、快速粘度仪(RVA)、X-射线衍射等研究添加不同比例大米蛋白对小麦淀粉理化特性的热力学特性、糊化特性、流变学特性、X-射线衍射以及冻融稳定性的影响。结果表明,添加大米蛋白的小麦淀粉糊化温度增加,糊化焓值降低。随着大米蛋白添加量的增加,小麦淀粉峰值黏度、低谷黏度、崩解值、终值黏度降和回生值分别从5266、3098、2168、4755、1657 cP降低到4003、2969、1034、4439、1470 cP,糊化温度从72.50 ℃增加到76.00 ℃。大米蛋白会抑制淀粉中结晶的溶解。同时,添加大米蛋白会使小麦淀粉凝胶的储能模量和损耗模量均降低,凝胶强度变弱,冻融稳定性降低。     

白糯小麦粉与糯米粉物化特性的比较

本试验研究了白糯小麦粉与普通小麦粉、糯米粉物化性质的差异,测定了白糯小麦粉、普通小麦粉和糯米粉的膨胀性、黏度特性、持水能力、糊透明度、冻融稳定性、消化性和糊化回生特性。结果表明,随温度的升高,白糯小麦粉、普通小麦粉和糯米粉的膨胀度随温度的升高呈递增趋势,但在较高温度下,白糯小麦粉的膨胀度高于糯米粉;与普通小麦粉比,白糯小麦粉有较高的峰值黏度、崩解值和较低的谷黏度、终黏度、回生值,糊化时间短,糊化温度低,不易消化;与糯米粉相比,白糯小麦粉的水合能力低,糊透明度差,峰值黏度、谷黏度、崩解值、终黏度和回生值低,糊化时间短,糊化温度高,易消化。白糯小麦粉的冻融稳定性好、抗回生能力强。     

Effect of Amylose Content on Gelatinization,Retrogradation and Pasting Properties of Flours from Different Cultivars of Thai Rice

Presently, rice cultivars are categorized according to amylose content into three groups: low, medium and high amylose content cultivars. The correlation of amylose content with gelatinization properties, retrogradation, and pasting properties of eleven cultivars of Thai rice were investigated. Rice flour was prepared from milled rice by the wet grinding process. Onset (T_o), peak (T_p) and conclusion (T_c) temperatures of gelatinization, (determined by DSC) were found to be highly positively correlated with amylose levels. This correlation could be used for prediction of amylose content of rice flour. Low amylose starch could also be characterized by low degree of retrogradation (%R). The data obtained from RVA‐viscograms (peak viscosity, breakdown, setback, and pasting temperature) can be used only for characterization of the group of low amylose starches (waxy rice). It was demonstrated that low amylose rice starch provided the highest peak viscosity and breakdown and the lowest setback and pasting temperature among the groups investigated.     

压榨型鲜湿米粉条凝胶质构特性及食用品质影响因素

以压榨型鲜湿米粉条凝胶品质影响因素为研究对象,主要探讨了大米粉基本理化指标、快速黏度分析(rapid visco analyze,RVA)糊化特性、大米淀粉结晶特性对压榨型鲜湿米粉条的食用品质及其凝胶质构特性的影响。研究表明大米粉直链淀粉的质量分数与米粉条的感官得分、质构特性指标(除黏附性、弹性外)呈显著或极显著正相关(P0.05,P0.01),大米粉支链淀粉质量分数与米粉条感官得分、质构特性指标(除黏附性、弹性外)呈显著或极显著负相关(P0.05,P0.01);大米粉粗蛋白(除与恢复性呈显著正相关外)、粗脂肪质量分数与米粉条凝胶特性和食用品质相关性不显著(P0.05);X射线衍射、傅里叶变换红外光谱2种方法分析得到的结晶度RX和RI均与米粉条的凝胶特性指标和食用品质感官得分均无显著相关性(P0.05)。RVA糊化特性参数中的峰值黏度、最低黏度和最终黏度与米粉条的感官得分、质构特性指标(除黏附性、弹性外)呈显著或极显著正相关性(P0.05,P0.01);衰减值虽与感官得分、凝胶质构特性指标(除与黏附性显著负相关外)均呈一定的负相关性,但均不显著(P0.05);而回生值则与米粉条感官得分、凝胶质构特性指标的硬度、胶着性、咀嚼性、恢复性均呈极显著正相关(P0.01)。由此可见,直链淀粉、支链淀粉质量分数及RVA糊化特性参数可用来预测压榨型鲜湿米粉条的食用品质关键性指标。     

Factor analysis of physicochemical properties of 63 rice varieties

A set of 63 Chinese‐adapted non‐waxy rice varieties of the indica and japonica subspecies was measured to extract simple indicators for rice quality evaluation. Approximate methods including amylose content (AC), gel consistency (GC), gelatinisation temperature (as measured by alkali spreading value, ASV), protein content, etc and instrumental methods including differential scanning calorimetry (DSC), viscoamylography (with a Rapid Visco‐Analyser, RVA) and texture profile analysis were adopted. Four sets of data, ie ordinary testing, flour pasting property, texture of the cooled flour gel, and visual appearance of whole milled grain and flour, were obtained and analysed for mutual relationships. Wide variations were observed in most of the measurements, eg AC (ranging from 6.3 to 28.2%), gelatinisation temperature (T_p, 65.8–83.0 °C), protein content (7.2–13.5%), pasting (peak viscosity, 92–319 RVU) and texture (hardness, 2.5–24.4 g) properties and grain appearance (grain length, 4.8–8.4 mm), to mention a few. Significant correlations were also detected among the four sets of data of the rice varieties, such as AC versus SB (setback viscosity) with a correlation coefficient of ?0.73, AC versus HRD (gel hardness) of 0.73, HRD versus FRC (gel fracturability) of 0.99, etc. Generally, the instrumental measurements including DSC, pasting and texture properties were highly correlated with the three ordinarily used indicators of rice quality, ie AC, GC and ASV. However, there was a lack of correlation between pasting properties and textural parameters, implying effects on gel texture of retrogradation of starch after cooling of the paste. Six factors were computed by principal component factor analysis that explained 80% of the variation in the traits, among which amylose content‐related (30.8%), gelatinisation temperature‐related (14.9%) and grain appearance‐related (11.1%) factors were most important. Gel pasting properties evaluated by RVA, and flour colour played less important roles in explaining total variation (accounting for a combined 23% of the eigenvalue loading). This report can be used to identify predictive parameters for rapid screening of rice genotypes for eating quality. © 2002 Society of Chemical Industry