抗性淀粉对香肠品质的影响

采用压热法制备小麦抗性淀粉,测定其持水性、乳化性和黏度特性,并与原淀粉比较;RS代替原淀粉添加到香肠中,通过测定肉糜的保水性以及运用物性仪对香肠进行质构分析,研究抗性淀粉对香肠品质的影响。结果表明,小麦抗性淀粉与原淀粉相比,持水性和乳化性较高,而黏度则较低;随着抗性淀粉替代量的增加,肉糜的保水性逐渐提高;与此同时,香肠的咀嚼性和粗糙感逐渐增大,而黏聚性则逐渐减小。通过对质构的分析发现,抗性淀粉可以提高香肠的弹性;抗性淀粉的替代量为80%时,香肠的硬度和弹性都达到最佳,综合品质最好。     

抗性淀粉对面条品质影响的研究

采用压热一酶法制备小麦抗性淀粉,并测定其持水性、乳化性和黏度特性.研究了小麦抗性淀粉对面团流变学特性、面条的物性参数(如硬度、黏聚性、弹性等)和食用品质的影响,并添加谷朊粉以改善面条品质.实验结果表明:小麦抗性淀粉的持水性、乳化性和黏度特性均显著低于小麦淀粉.随着抗性淀粉添加量的增加,面粉的粉质特性显示面团的吸水率增高,稳定时间减少,弱化度增加;面条的物性参数显示黏聚性和弹性在8%RS时分别达到最小值和最大值,但变化不明显,而面条的硬度和黏着性则变化较大.最终确定添加8%抗性淀粉、2%谷朊粉时,所制作的面的品质达到最佳.     

淮山药淀粉及其抗性淀粉理化性质的比较

分析比较了淮山药淀粉及压热法制备的淮山药抗性淀粉的理化性质。结果表明:淮山药淀粉颗粒呈圆形或卵圆形,属C型淀粉;抗性淀粉颗粒为不规则形、多角形,尺寸较原淀粉有所减小。2种淀粉的化学结构相似,与原淀粉相比,抗性淀粉没有生成新的基团。抗性淀粉的溶解度、膨润度、透明度均低于原淀粉,而持水性、乳化性优于原淀粉;糊化温度较原淀粉高,热稳定性和冷稳定性更好。原淀粉糊和抗性淀粉糊均为屈服-假塑性流体,原淀粉糊易剪切稀化,抗性淀粉糊耐机械力的性能好。     

马铃薯抗性淀粉的微波预处理条件及性质研究

采用微波-酶解复合法制备马铃薯抗性淀粉,在酶作用条件固定的条件下,研究微波预处理对马铃薯抗性淀粉含量的影响。结果表明,在淀粉乳浓度15%、微波作用时间90 s、微波功率800 W的条件下,得到的抗性淀粉含量最高为17.2%。在此基础上对优化制得的马铃薯抗性淀粉理化性质进行研究。结果表明,与原淀粉相比,马铃薯抗性淀粉表面变得粗糙不平,产生了凹陷的不规则形态;马铃薯抗性淀粉的持水性、吸水性明显高于原淀粉,而乳化能力及乳化稳定性都要低于原淀粉;马铃薯抗性淀粉比原淀粉更难糊化,糊粘度也远低于原淀粉,但粘度稳定性及凝胶能力明显强于原淀粉;马铃薯抗性淀粉具有较强的抗酸解性,可以广泛应用于酸性食品中。     

红薯抗性淀粉的结构表征及性质测定

目的:研究超声酸解法制备的红薯抗性淀粉的结构和性质。方法:通过红外光谱(IR)、扫描电镜(SEM)、差示扫描量热法(DSC)及X-射线衍射(XRD)分析技术分析比较了红薯原淀粉和红薯抗性淀粉的结构,并测定了淀粉的的含水率、乳化性、透明度和比容积等性质。结果:淀粉形貌由原来表面光滑的多面体小颗粒状变为表面有褶皱的蓬松的大块片状结构,晶型由A型转变为B型,结晶度增大,热稳定性提高。抗性淀粉的含水率、乳化性、透明度和比容积降低,而持水性增加。结论:红薯抗性淀粉可以作为添加剂用于功能食品的研究开发。     

怀山药抗性淀粉理化性质及体外消化性研究

分析比较怀山药淀粉和压热法制备的怀山药抗性淀粉的理化性质及消化特性。结果表明:怀山药淀粉颗粒表面光滑,呈不规则且大小不一的椭球形、三角形等形态,属于C型淀粉;抗性淀粉颗粒特征消失,呈现表面疏松的片层状结构。2种淀粉化学结构相似,抗性淀粉没有形成新的基团。与原淀粉相比,抗性淀粉分子量分布更加集中。抗性淀粉的糊化峰值温度高于原淀粉的,因此其热稳定性更高。抗性淀粉的透明度低于原淀粉的。水浴温度低于75℃时,抗性淀粉的持水性大于原淀粉的,而当水浴温度高于原淀粉糊化温度时,原淀粉的持水性明显高于抗性淀粉的;体外模拟人体消化试验表明,抗性淀粉比原淀粉更耐消化。     

两种小颗粒淀粉比较

对大米淀粉和小麦B淀粉化学组分、性质进行研究,结果表明:小麦B淀粉含有蛋白质、脂肪、戊聚糖等成分明显高于大米淀粉;大米淀粉和小麦B淀粉的结晶结构相似,都为A型。大米淀粉和小麦B淀粉重量平均分子量(或重量平均聚合度)、数量平均分子量(或数量平均聚合度)、分散度都相当接近,大米淀粉膨润力小于小麦B淀粉,而蓝值、溶解度、粘度均大于小麦B淀粉。     

微波韧化辅助制备马铃薯抗性淀粉性质的研究

优化马铃薯淀粉制备工艺,采用微波、韧化辅助处理以增加抗性淀粉含量。并对淀粉增抗机制与增抗后淀粉的理化特性进行研究。结果表明,与原淀粉相比,增抗处理后的马铃薯淀粉颗粒表面受到严重侵蚀,相互粘连,呈簇状存在;结晶度比原淀粉显著提高,淀粉分子趋于有序化重新形成的晶体结构;To、Tp、Tc、△H增加,用热处理破坏结晶结构需要更多的能量;淀粉糊的黏度降低,糊化温度提高;抗消化性与抗性淀粉热稳定性增强;吸水性、乳化性与乳化稳定性低于原淀粉,持水能力略微增加。     

马铃薯抗性淀粉理化性质的研究

以马铃薯原淀粉为对照,研究了纤维素酶-压热法制备的马铃薯抗性淀粉的理化性质。结果表明,马铃薯原淀粉颗粒呈椭球形,表面光滑;而抗性淀粉的颗粒状结构消失,形成了连续的致密结构,表面不再光滑。红外光谱分析表明,抗性淀粉分子中未出现新的基团,只较原淀粉形成了更多的氢键。马铃薯原淀粉的分子晶型为A型,整体结晶度为22.82%;抗性淀粉的分子晶型为B型,整体结晶度为29.64%。马铃薯抗性淀粉的溶解度、透明度远远低于原淀粉;膨润度、持水性优于原淀粉。抗性淀粉的沉降速度较快,沉降性比原淀粉强。原淀粉糊化温度为65.8 ℃,峰值黏度可达到10 770 mPa·s;而抗性淀粉其糊化温度高于95 ℃。     

小麦抗性淀粉的理化性质研究

利用压热法制备小麦抗性淀粉RS3,并考察其部分理化性质及结构性质。结果表明,该产品含抗性淀粉13.89%,透光率较好,持水力、溶解度和膨胀度都随水浴加热温度的升高而上升。其淀粉-碘复合物最大吸收波长为594 nm,碘吸收曲线在580~610 nm之间呈较宽的吸收峰。该产品颗粒形状大部分为圆形,偏光十字明显,多呈十字型,且交叉点均位于颗粒中心;起糊温度为68.7℃,糊化不易发生,但较易老化。淀粉颗粒结晶结构为C型,仍保留了小麦淀粉红外光谱的特征吸收峰。     

湿热处理对小麦淀粉结构和性质影响

对小麦淀粉进行湿热处理,研究不同初始含水量对小麦淀粉结构和性能影响。实验结果表明,经湿热处理后小麦淀粉颗粒表面出现凹坑,随初始水分含量增加,淀粉颗粒表面凹坑数量增加,同时粘结现象变得严重;湿热处理小麦淀粉糊化温度随初始含水量增加而升高;经湿热处理后小麦淀粉对酸和酶敏感性增加,更易被酸和酶水解。     

PHYSICAL PROPERTIES OF SUGAR-SNAP COOKIES USING GRANULE SURFACE DEPROTEINATED WHEAT STARCH

The physical properties of soft wheat starch granule surface proteins and soy flours or isolates, which contribute to the texture of sugar‐snap cookies was studied. Soft wheat flour was deproteinated and cookies were produced containing 0, 10, 20 or 30% soy flour, or one of two types of ground, textured soy flour. Color, fracture force and spread ratio of cookies were determined. Cookies formulated with wheat starch stripped of the starch granule surface proteins exhibited significant alterations in diameter, fracture force, thickness and surface cracking. Cookies containing ground, textured soy flour and protein‐stripped starch granule wheat flour were larger, thinner and had more surface cracking than those produced with nontextured soy flour. Wheat starch granule surface proteins appear to partially mediate the interaction of proteins and starch in a sugar‐snap cookie system.     

干热处理对藜麦淀粉结构和理化性质的影响

以高筋小麦粉为原料添加酵母制作面团,在温度28℃、湿度80%条件下发酵1～6 h,提取小麦淀粉。研究发酵时间对小麦直链淀粉含量、损伤淀粉含量、粒径、颗粒表面结构、糊化及消化特性的影响。结果表明：面团发酵1 h后直链淀粉含量和损伤淀粉含量均显著低于原淀粉(P<0.05)。快速黏度分析结果表明,发酵1 h的小麦淀粉峰值黏度、热浆黏度和冷浆黏度最低。发酵处理后淀粉的粒径均小于原淀粉,其中发酵5 h的平均粒径最小。扫描电镜结果表明,发酵6 h的小麦淀粉颗粒表面出现破裂现象。体外消化实验表明,发酵5 h和6 h小麦淀粉的消化速率最高,发酵后抗性淀粉含量低于原淀粉,而慢消化淀粉含量高于原淀粉(P<0.05)。     

两种抗性淀粉的结构特征及体外消化性研究

本实验对小麦抗性淀粉和马铃薯抗性淀粉结构特征及体外消化性进行研究。结果表明,与小麦抗性淀粉相比,马铃薯抗性淀粉直链淀粉含量更高,分子质量分布更集中,热稳定性更高。两种抗性淀粉粒径相差不大,均为C型结构,化学结构相似,没有基团差异。小麦抗性淀粉分子颗粒完整,表面光滑,呈不规则的椭圆形,马铃薯抗性淀粉分子为不规则多面体,分子表面粗糙,有凹陷,且有少量的层状起伏。体外消化试验表明:马铃薯抗性淀粉具有更强的抗消化能力,血糖指数分别为40.62、40.50（GI<55）,属于低GI食品。相关性分析结果为抗性淀粉体外消化率与其直链淀粉含量、碘吸收峰负相关,与其结晶度、热焓值显著负相关,与比表面积正相关。     

Starch characteristics of transgenic wheat (Triticum aestivum L.) overexpressing the Dx5 high molecular weight glutenin subunit are substantially equivalent to those in nonmodified wheat

The effects of engineering higher levels of the High Molecular Weight Glutenin Dx5 subunit on starch characteristics in transgenic wheat (Triticum aestivum L.) grain were evaluated. This is important because of the interrelationship between starch and protein accumulation in grain, the strong biotechnological interest in modulating Dx5 levels and the increasing likelihood that transgenic wheat will be commercialized in the U.S. Unintended effects of Dx5 overexpression on starch could affect wheat marketability and therefore should be examined. Two controls with native levels of Dx5 were used: (i) the nontransformed Bobwhite cultivar, and (ii) a transgenic line (Bar-D) expressing a herbicide resistant (bar) gene, and they were compared with 2 transgenic lines (Dx5G and Dx5J) containing bar and additional copies of Dx5. There were few changes between Bar-D and Dx5G compared to Bobwhite. However, Dx5J, the line with the highest Dx5 protein (×3.5) accumulated 140% more hexose, 25% less starch and the starch had a higher frequency of longer amylopectin chains. These differences were not of sufficient magnitude to influence starch functionality, because granule morphology, crystallinity, amylose-to-amylopectin ratio, and the enthalpy of starch gelatinization and the amylose-lipid complex melting were similar to the control (P > 0.05). This overall similarity was borne out by Partial Least Squares-Discriminant Function Analysis, which could not distinguish among genotypes. Collectively our data imply that higher Dx5 can affect starch accumulation and some aspects of starch molecular structure but that the starches of the Dx5 transgenic wheat lines are substantially equivalent to the controls. PRACTICAL APPLICATION: Transgenic manipulation of biochemical pathways is an effective way to enhance food sensory quality, but it can also lead to unintended effects. These spurious changes are a concern to Government Regulatory Agencies and to those Industries that market the product. In this study we examined if making "specific" changes to the composition of gluten proteins in wheat seeds would simultaneously alter starch, as their synthesis is interrelated and the molecular structure of both determine flour functionality. This information may be used to address issues of "substantial equivalence" and to inform Industrial End-Users of possible changes in product performance.     

Effect of gamma‐ray irradiation on the physicochemical properties of flour and starch granule structure for wheat

Effect of gamma irradiation on the physicochemical properties of flour and starch granule structure of wheat was compared to non‐irradiated wheat. The moisture content of wet gluten and titratable acidity of wheat flour were significantly affected by gamma irradiation. This treatment also destroyed the starch granules of wheat grain and their breakage augmented as the dose of gamma irradiation increased, apparently resulting in the increase of small starch granules. Probably, these results were due to the disruption of large molecule, such as proteins, lipids and starch. The irradiated wheat flour for RVA pasting properties (flour viscosity) was also evaluated. Besides the difference in RVA profile, starch pasting curves showed a considerable decrease for six main parameters as gamma irradiation dose at different velocity increased.     

压热法结合反复冻融制备小麦抗性淀粉及其理化性质研究

以小麦淀粉为原料,利用压热法制备抗性淀粉,再经过反复冻融,以期提高产品的抗性淀粉含量。对产品的颗粒形貌、碘吸收曲线、持水力、膨胀度、溶解度等理化性质进行了测定。结果表明,反复冻融次数为6次时得到的小麦抗性淀粉含量最高,为18.31%,经过反复冻融处理的小麦抗性淀粉,颗粒呈不规则形,且在碘吸收曲线中稍微偏向直链淀粉吸收峰,表明其可能含有较多的直链淀粉。与小麦原淀粉相比,经反复冻融处理的小麦抗性淀粉的持水力与膨胀度显著增加,而溶解度显著降低。     

槲皮素和芦丁对小麦淀粉的消化特性及其之间相互作用的研究

本文通过模拟小麦淀粉的体外消化实验研究了槲皮素和芦丁与小麦淀粉复合后的消化特性差异,并通过淀粉与碘的显色反应、红外光谱和X-射线衍射等试验研究槲皮素和芦丁与小麦淀粉的相互作用。结果表明:在槲皮素和芦丁与小麦淀粉的混合体系中,随着老化时间的延长,快消化淀粉显著减少（P<0.05）,慢消化淀粉和抗性淀粉显著增加（P<0.05）。槲皮素和芦丁的添加,对淀粉葡萄糖苷酶和α-淀粉酶的活性均有抑制作用。槲皮素或芦丁与小麦淀粉之间存在相互作用,并通过氢键或疏水键相互结合。槲皮素和芦丁对酶的抑制和与小麦淀粉之间的相互作用,降低了小麦淀粉的消化性,增加淀粉的抗消化性,为开发降血糖等相关功能食品的开发奠定了理论基础。