酶法及压热-酶法制备大米抗性淀粉的理化性质比较

对酶法及压热-酶法制备的大米抗性淀粉和淀粉凝胶的理化性质进行比较。结果表明,酶法及压热-酶法制备的大米抗性淀粉含水量从11.88%分别下降到4.05%和3.98%;大米淀粉凝胶水分含量也明显下降。酶法和压热-酶法制备的大米抗性淀粉的溶解度和膨润力都随温度的升高而增加。但两种大米淀粉凝胶的溶解度随温度呈现缓慢下降趋势。酶法制备的抗性淀粉的糊化黏度和回生值比压热-酶法大,而两种淀粉凝胶峰值黏度、谷值黏度、最终黏度、衰减值、回生值均明显降低。压热-酶法制备的大米抗性淀粉和淀粉凝胶偏光十字较弱。两种淀粉凝胶的硬度和弹性均显著增加,并且压热-酶法的硬度和弹性最大,但胶黏性较小。     

挤压加工对苦荞粉理化性质的影响

为了阐明挤压加工技术对苦荞粉理化性质的影响,分别研究了不同挤压温度、物料水分和螺杆转速对挤压苦荞粉的吸水性指数、水溶性指数、膨胀势、糊化及凝胶特性的影响规律。结果表明:与未挤压苦荞粉相比,经挤压改性后的苦荞粉在30℃水浴时有更好的吸水性和水溶性;在100℃水浴时的水溶性增大,吸水性减小;膨胀势、糊化特征值及凝胶特征值均明显升高。随挤压温度升高,挤压苦荞粉的峰值粘度、衰减值增大,谷值粘度、回生值降低,制成的凝胶品质更好;随物料水分升高,吸水性指数、膨胀势、各糊化特征值显著增大,水溶性指数明显降低,低物料水分形成的凝胶品质较好;随螺杆转速升高,水溶性指数增大,吸水性指数和峰值粘度、谷值粘度、衰减值稍降低,膨胀势先增大后减小,转速越高的苦荞粉的凝胶品质越好。综合而言,物料水分变化对挤压苦荞粉的各理化性质影响最大。吸水性指数和水溶性指数与糊化特性、凝胶特性都有显著相关性(P0.05);膨胀势与糊化特性极显著正相关(P0.01),与凝胶特性没有显著相关性。     

酸解和乙酰化改性对木薯淀粉性质的影响

以木薯淀粉为原料,对酸解淀粉、乙酰化淀粉及酸解乙酰化淀粉的糊性质进行了研究,并用扫描电子显微镜、X射线衍射仪和傅里叶变换红外光谱仪对改性淀粉的形貌和结构进行了分析。结果表明:木薯淀粉经酸解改性改善了糊的透明度,膨胀度有所降低,糊化温度升高,峰值黏度显著降低,凝沉性有所改善;乙酰化改性增加了淀粉糊的透明度,膨胀度提高,降低了糊化温度,峰值黏度增加,糊的抗凝沉性增强但热糊稳定性差;酸解乙酰化复合改性显著提高了淀粉糊的透明度,降低淀粉的膨胀度及糊化温度,峰值黏度显著降低,抗凝沉性明显增强,冷、热糊稳定性提高。扫描电镜、X衍射数据及红外图谱表明,3种变性处理均没有改变木薯淀粉的晶型和基本结构,颗粒形貌也没有发生显著变化。     

发芽对糙米理化特性的影响

采用富集γ-氨基丁酸(GABA)的优化糙米发芽工艺条件,研究糙米发芽前后内部结构和理化特性的变化,主要包括膨胀度、透明度、冻融稳定性、凝沉特性、糊化特性及质构特性等。结果表明:糙米发芽后,膨胀度增大,且随温度的升高而提高;透光率比发芽前升高了20%;冻融稳定性提高,凝沉特性得到改善,这说明发芽使糙米不易老化,有助于食品货架期的延长;峰值黏度降低,糊化温度基本不变;糙米发芽后凝胶黏性有所提高,硬度和胶凝性均降低;电镜分析结果显示,发芽后整个米粒结构变得较疏松。通过对糙米淀粉酶活力的测定,表明发芽后糙米淀粉酶活力上升。综上得出,发芽对糙米的理化特性有一定的改善作用。     

Physicochemical properties of thermal alkaline treated pigeonpea (Cajanus cajan L.) flour

Thermal alkaline treatment, normally used for corn, was applied to pigeonpea grains. Starch granules were isolated using wet milling and alkaline treatments. Effects of the calcium hydroxide [Ca(OH)₂] concentration in the range of 0–1% (w/v) on granule structure, crystalline structure, chemical composition, and physicochemical, thermal, and pasting properties of isolated starch granules were determined. Compared to native samples, thermal alkaline treated samples had higher protein, lipid, calcium, and phosphorus contents, but lower starch and amylose contents. Thermal alkaline treatment increased starch granular size and gelatinization temperatures, but decreased relative crystallinity, gelatinization enthalpy, swelling power, solubility, amylose leaching, and the pasting viscosity. Amylose-lipid complexes were not found in thermal alkaline treated flours. As the Ca(OH)₂ concentration increased, the amylose content, relative crystallinity, gelatinization temperature, and enthalpy also increased, but the swelling power, solubility, amylose leaching, and paste viscosity decreased. A higher Ca(OH)₂ concentration produced more stable starch granules that resisted re-gelatinization.     

低取代度乙酰化绿豆淀粉的性质

以绿豆淀粉为原料,冰醋酸为乙酰化剂,制备低取代度的乙酰化绿豆淀粉。对乙酰化绿豆淀粉的膨润力、溶解度、凝沉性、透明度、黏性、质构特性等进行研究。结果表明：与原淀粉相比,经过乙酰化处理的绿豆淀粉透明度、膨润力、溶解度均比原淀粉有所增加,糊化温度降低,谷值黏度、末值黏度有所升高,而峰值黏度、衰减值则降低,绿豆淀粉乙酰化后凝胶特性也有所改善。     

热处理对不同直链淀粉含量的玉米淀粉理化性质的影响

采用快速黏度分析法、离心法、差示扫描量热分析法、动态流变仪分析法等,研究了干热与湿热处理对3种不同直链淀粉含量的玉米淀粉糊化性质、膨润性质、热力学性质、流变性质的影响,为淀粉的物理改性研究和加工应用提供理论依据。结果表明,干热处理使淀粉更易糊化,表现为3种玉米淀粉糊化温度降低,溶解度、膨胀度增加。湿热处理加大糊化难度,使3种玉米淀粉的糊化温度升高,膨胀度降低。热处理使玉米淀粉糊稠度、糊化焓值降低。蜡质玉米淀粉经热处理后,溶解度和老化率增加。流变性质测定结果表明,湿热处理不利于高直链玉米淀粉黏弹性凝胶的形成。     

微波对玉米淀粉性质影响的研究

采用微波对30%水分含量的玉米淀粉进行处理。结果表明微波处理降低了淀粉的膨胀度和溶解度、冻融稳定性以及焓值,提高了糊化转变温度、转变温度范围。玉米淀粉经处理后糊化起始温度升高、黏度降低。以上数据表明微波处理使淀粉颗粒内淀粉分子发生重排,产生了新的不同稳定性的结晶体,从而导致微波淀粉内部更加有序的结晶排列。     

Some characteristics of acetylated, cross-linked and dual modified Indian rice starches

Starches from broken rice grains derived from three varieties (PUSA-44, PR-106, and PR-114) were modified by hydroxypropylation with propylene oxide and esterification with adipic acid anhydride and/or vinyl acetate. Degree of substitution and acetyl contents (in parentheses) was relatively low; ranges between 0.02 (0.53%) and 0.12 (3.09%) for hydroxy-propylated cross-linked and acetylated starch samples. The acetylation and dual modification of starches increased the paste clarity, solubility, swelling power, sediment volume, and gel strength but decreased the gel elasticity in all the three varieties. However, the adhesiveness increased only upon dual modification in PUSA-44 and decreased in other two varieties. Cross-linking reduced the solubility, swelling power, sediment volume, and gel elasticity while increased the paste clarity, gel strength and adhesiveness. The physico-chemical characteristics of relatively high amylose variety PUSA-44 among three varieties were significantly lower than those from varieties with low amylose content whereas PUSA-44 had shown improved gel properties as compared to other two varieties.     

小米淀粉与玉米淀粉糊性质比较研究

对小米淀粉和玉米淀粉糊性质进行较详细比较研究,包括透明度、冻融稳定性、凝沉性、膨胀力、酸解、酶解,和介质对糊粘度性质影响。结果表明,小米淀粉与玉米淀粉相比,糊的凝胶稳定性好、持水力强、膨胀力高、糊化温度高、热焓变值大、但透明度较差、冻融稳定性不佳、热稳定性差;且氯化钠及糖溶液对小米淀粉糊粘度性质影响较大。     

豆类纤维素和蛋白质对豆淀粉理化性质影响研究

选取豌豆、红豆和绿豆三种样品豆,并分别制备豆全粉、除纤维素豆粉、豆淀粉三种样品,研究它们溶胀度、可溶指数、直链淀粉含量、糊化性、质构性等性质。结果表明,三种样品豆的豆全粉、除纤维素豆粉、豆淀粉的粘度差异较大,其中以豆淀粉粘度最高,除纤维素豆粉次之,豆全粉粘度最低;豆淀粉硬度、胶粘性和咀嚼性高于豆全粉和除纤维素豆粉;随温度升高,三种样品豆的豆全粉、除纤维素豆粉、豆淀粉溶胀度和可溶指数均呈现递增趋势,其中豆全粉可溶指数明显高于除纤维素豆粉和豆淀粉;在较高温度下,豆淀粉溶胀度要高于除纤维素豆粉和豆全粉。     

不同取代度板栗淀粉磷酸酯理化特性研究

通过改变板栗淀粉酯化反应的时间,制得不同取代度的板栗淀粉磷酸酯,对其理化性质进行研究。结果表明:原板栗淀粉颗粒表面光滑,可见椭圆形、三角形、梨形等;改性后,淀粉颗粒出现不同程度凹陷、破损和裂痕。同时,随着取代度的增加,其透明度、溶解度、膨胀度增加,冻融稳定性提高。质构分析显示,改性后,其凝胶的硬度、脆裂性、胶黏性和咀嚼性降低,内聚性和黏附性增大。差示扫描量热分析显示,改性后,其糊化初始温度、吸热高峰温度和糊化最终温度降低,糊化热焓值显著变小。糊化特性显示,改性后的淀粉糊黏度提高,糊化温度降低,黏度稳定性较好。     

脱脂脱蛋白处理对小麦A、B淀粉理化性质的影响

为阐明脂类和颗粒结合蛋白对小麦A、B淀粉理化和结构性质的影响,以豫麦49-198为试验材料,采用面团法制备小麦淀粉,沉降法分离小麦A、B淀粉,并对其进行脱脂脱蛋白处理,研究了处理前后小麦A、B淀粉组成、颗粒结构、溶解度与膨胀度、糊特性、热特性等性质的差异。结果表明:与未处理的小麦A、B淀粉相比,脱脂脱蛋白处理后小麦A、B淀粉颗粒表面较光滑,分散程度较均匀,偏光十字的位置和形状无显著性差异,清晰度显著增加;溶解度和膨胀度随温度的增长趋势显著增加;起始温度、峰值温度、终值温度、透明度、峰值黏度、衰减值、回生值显著增加;冻融稳定性、峰值时间显著降低;热焓值无显著变化。这为小麦A、B淀粉更好的应用提供理论参考。     

短链菊粉对玉米磷酸酯双淀粉热力学特性的影响

通过添加不同比例的短链菊粉（inulin,I）,研究其对玉米磷酸酯双淀粉（maize distarch phosphate,MDP）质构、糊化特性和热力学性质的影响。采用质构仪、Brabender黏度计和差示扫描量热仪（differentialscanning calorimeter,DSC）分别测定了菊粉、MDP及两者复配物的凝胶质构特性、黏度特性、糊化及相变特性等参数。结果表明：菊粉的添加增加了玉米磷酸酯双淀粉的凝胶强度、黏附力、硬度、回复性及糊化起始温度（To）、峰值温度（Tp）和终止温度（Tc）,当I和MDP质量比为3∶7时,复配物凝胶的黏附力、硬度和回复性较MDP依次增加了33%、145%和650%,To和Tp值分别增加了5.06%和5.10%;菊粉的添加降低了MDP的峰值黏度、崩解值、回生值及糊化吸热值,当I和MDP质量比为3∶7时,峰值黏度、崩解值和回生值较MDP依次降低了73.43%、87.35%和79.32%。综合来看,菊粉增强了MDP凝胶的稳定性和强度,提高了MDP的糊化温度、糊液黏度和糊液稳定性,同时有效抑制了MDP的回生。     

Physicochemical,crystallinity, pasting and thermal properties of heat‐moisture‐treated pinhão starch

The effect of heat‐moisture treatment (HMT) on the properties of pinhão starches under different moisture and heat conditions was investigated. The starches were adjusted to 15, 20 and 25% moisture levels and heated to 100, 110 and 120°C for 1 h. The X‐ray diffractograms, swelling power, solubility, gel hardness, pasting properties and thermal properties of the native and HMT pinhão starches were evaluated. Compared to native starch, there was an increase in the X‐ray intensity and gel hardness of HMT starches, with the exception of the 25% moisture‐treated and 120°C heat‐treated starch. HMT reduced the swelling power and solubility of the pinhão starches when compared to native starch. There was an increase in the pasting temperature, final viscosity and setback and a decrease in the peak viscosity and breakdown of HMT pinhão starches compared to native starch. HMT increases the gelatinisation temperature of native pinhão starch and reduces gelatinisation enthalpy.     

Physicochemical,morphological, thermal,pasting, and textural properties of starch acetates

Acetylated starches are a commercially important group of modified starch known for their reduced retrogradation tendency, high clarity, low viscosity, high swelling power, and lower gelatinization temperature and time. Due to these remarkable properties, acetylation is a commonly used chemical modification for preparing stabilized starches. This review summarizes the methods used for preparation of starch acetates and corresponding effects of acetylation on morphological, thermal, pasting, digestibility, textural, and other functional characteristics of starches isolated from various botanical sources. Starch acetates are also useful as packaging material, as wall material for encapsulating active ingredients, and to improve the storage stability of different products.     

Investigations of the Great Northern Bean (Phaseolus vulgaris L.) Starch: Solubility, Swelling, Interaction with Free Fatty Acids, and Alkaline Water Retention Capacity of Blends with Wheat Flours

The solubility and swelling of Great Northern bean (Phaseolus vulgaris L.) starch was both temperature and pH dependent. Acetylation of starch decreased the solubility while oxidation increased the solubility as a function of temperature. Solubility of purified starch was highest at pH 6.0. Over a temperature range 60–90°C, acetylation increased swelling while oxidation reduced it. Both acetylation and oxidation resulted in reduced swelling of starch over a pH range 2–10. Addition of fatty acids (palmitic, stearic, and linoleic) to the purified starch reduced the Brabender Amylograph viscosity and raised the gelatinization temperature of starch. Replacement of wheat flours by starch increased the alkaline water retention capacity to a similar extent for the two flours tested.     

Hydrothermal Modifications of Tropical Tuber Starches. 1. Effect of Heat‐Moisture Treatment on the Physicochemical,Rheological and Gelatinization Characteristics

Cassava, sweet potato and arrowroot starches have been subjected to heat‐moisture treatment (HMT) under different conditions using a response surface design of the variables. A comparative study was performed on the pasting properties, swelling behaviour and the gelatinization properties of the modified starches and also on the rheological and textural properties of their pastes. X‐ray diffraction studies have shown that cassava starch exhibited a slight decrease in crystallinity, whereas sweet potato and arrowroot starches showed an increase in crystallinity after HMT at 120ºC for 14 h with 20% moisture. The swelling volume was reduced and the solubility was enhanced for all three starches after HMT, but both effects were more pronounced in the case of arrowroot starch. The decrease in paste clarity of the starch after HMT was higher in the case of cassava and sweet potato starches. Viscosity studies showed that the peak viscosity of all three starches decreased after HMT, but the paste stability increased as seen from the reduced breakdown ratio and setback viscosity. Studies on rheological properties have shown that storage and loss moduli were higher for the starches heat‐moisture treated at higher moisture and lower temperature levels than the corresponding native starches. Storage of the gel at ‐20ºC resulted in a significant increase in storage modulus for all the three starches. All the textural parameters of the gels were altered after the treatment which depended on the nature of the starch and also the treatment condition.     

糯糙米发芽过程中淀粉理化特性的变化

本论文选取糙糯米为研究对象,分别对其进行不同程度的发芽处理（调控发芽时间）,然后经水磨碱法提取淀粉,探讨不同发芽处理时间对糙糯米淀粉基本理化指标及糊化、流变与质构特性的影响规律。结果表明：发芽处理提高了淀粉的溶解度、膨胀度、起糊温度与热糊稳定性,使其凝沉特性及流动性得以改善,但降低了淀粉糊的储能模量、损耗模量、内聚性和胶黏性,且随着发芽时间的延长,趋势更加明显。这些研究结果表明发芽处理可以显著降低糙糯米淀粉糊的黏度、内聚性与咀嚼性,增强其吸水能力及流动能力,改善其凝沉特性,有利于其在食品加工及速冻食品中的应用,呈现出非常好的工业应用前景。     

Effect of ionic gums and dry heating on physicochemical,morphological, thermal and pasting properties of water chestnut starch

Starch from water chestnuts (Trapa natans) was isolated and modified by dry heating and hydrocolloids [carboxy methyl cellulose (CMC) and sodium alginate]. Native and modified starches were evaluated for their physicochemical, pasting, thermal and morphological properties. Pasting and thermal properties were studied using Rapid Visco Analyzer (RVA) and Differential Scanning Calorimeter (DSC) respectively. Morphological properties were studied by Scanning Electron Microscopy (SEM). Modification of the starch by dry heating with and without gums reduced paste clarity and increased the water and oil binding capacity; solubility and swelling power decreased. Dry heating of native starch increased peak viscosity; however, with addition of CMC, peak viscosity decreased. Starch modified with CMC and 4 h heating exhibited lowest gelatinization temperature (T₀). Pasting characteristics of native water chestnut starch were largely affected by the addition of gums and/or heat treatment. Overall onset gelatinization temperature reduced with heat treatment and addition of gums. Morphological studies revealed no significant variation in starch granule size. Starch granules were seen agglomerated because of leaching of amylose and granule interspacing decreased with addition of gums.