湿热处理对不同晶型淀粉理化性质及消化性的影响

采用三种不同晶型淀粉即玉米淀粉(A型)、马铃薯淀粉(B型)、豌豆淀粉(C型)为原料,在水分含量为25%、温度120℃条件下湿热处理13 h,研究湿热处理对不同晶型淀粉的理化性质及消化性的影响。研究表明,与原淀粉相比,经湿热处理的三种淀粉的结晶结构均发生了改变,玉米淀粉由A型变为了A+V型,马铃薯淀粉和豌豆淀粉分别由B型和C型变为了A型;三种淀粉颗粒表面均出现了不同程度的破损;三种淀粉的部分颗粒的偏光十字的中心强度有所减弱;三种淀粉样品的糊化温度均升高,但A型和B型淀粉的焓值降低,而C型淀粉的焓值升高;三种淀粉的抗性组分含量均有所升高,抗消化性显著增强,其中C型淀粉变化最明显。     

Scanning Electron Microscopy Studies of Wheat,Potato and Corn Starch during Gelatinization

The gelatinization of a commercial wheat and potato starch and two types of corn starch (Amaizo Amylomaize VII and Amaizo Amioca Pearl starch) was examined by the scanning electron microscope. Concomitantly, the loss of birefringence in the wheat, potato and corn starch was followed with the light microscope. Swelling and deformation of the starch granules observed in the scanning electron microscope correlated with the loss of birefringence in the light microscope. The gelatinization range of the starches was detected with the scanning scope. Swelling of the wheat starch granules was first observed in the larger A-type granules. Amylomaize VII retained granular structure until approximately 95 °C even though birefringence changes were observed as low as 69°C. Some evidence of structural changes were evident at 83°C. Amioca Pearl underwent structural changes at approximately 68°C and abruptly lost granular structure at approximately 71 °C.     

几种淀粉的相对分子质量分布、微晶结构及形貌的研究

以小麦、马铃薯、甘薯、玉米、芋头为原料提取淀粉。采用碘兰值法、凝胶色谱、X衍射和扫描电镜,研究淀粉组成及淀粉级分的特性、淀粉的晶体特性和微观形态,为淀粉类食品的深加工提供理论基础。研究表明,芋头淀粉的碘兰值最小,其他4种淀粉碘兰值相差不大。玉米淀粉为高直链淀粉,小麦淀粉的3个级分较明显。马铃薯淀粉表现为B型X衍射图谱的特征,甘薯淀粉表现为C型X衍射图谱的特征,而小麦淀粉、玉米淀粉和芋头淀粉表现为A型X衍射图谱的特征,马铃薯淀粉的结晶度最小,玉米淀粉的结晶度最大、微晶尺寸最小,甘薯淀粉的微晶尺寸最大。     

Studies on Starch Granules

In X-ray diffractometric studies on starch granules of many kinds of plant species, we found a variety of intermediate C-type patterns. In particular, specimens of sweet potato starch granules varied from nearly the A-type pattern to nearly the B-type pattern. In these studies, we also found that spheroids of short chain amylodextrin showed very sharp diffraction patterns and that we could form amylodextrin spheroids with various types of X-ray diffraction patterns by varying the conditions of recrystallization. Then we showed that the X-ray patterns and physical properties of many kinds of cereal and root starches varied to some extent depending on the environmental conditions prevailing during the growth period. We examined the formation and the growth of starch granules in corn endosperm and the inner structures of these granules from the beginning to the end of their maturation by electron microscopic observations. We proved also, the appositive growth of starch granules using radio-active carbon dioxide. Then we tried to form starch granules in vitro. But the spheroids obtained from solutions of starch components were entirely different from natural starch granules. From the findings in these experiments, an ultramacromolecular concept of the starch granule is proposed.     

Hydrothermal Modification of Starches: The Difference between Annealing and Heat/Moisture -Treatment

Annealing and heat/moisture-treatment both cause a physical modification of starches without any gelatinization, or any other damage of the starch granules with respect to size, shape or birefringence only via a controlled application of heat/moisture. Since with respect to the application properties (gelatinization. viscosity etc.) almost idential modifications can be obtained with both treatments, there was no exact differentiation between the two treatments types. By application of both treatments as well as a combination of both to potato starch it could be demonstrated that both treatments cause completely different alterations of the internal granule structure. From the interpretation of the Brabender viscosity, the sorption isotherm, the DSC-curves and the X-ray diagrams it could be confirmed that a heat/moisture-treatment always means a structure alteration from a B-type in the direction of an A-type structure, whereas within annealing processes the property alteration have to be explained by a modification of the binding forces between the crystallites and the amorphous matrix.     

淀粉颗粒形貌与结构的研究

利用光学显微镜对玉米、木薯、马铃薯淀粉颗粒形及结构特征进行了详细的研究和讨论，揭示了不同淀粉颗粒形貌及结构特征之间的共同点和差别，提出了木薯和马铃薯淀粉颗粒首端和尾端的概念以及玉米和木薯淀粉颗粒也存在轮纹和脐点的观点。     

玉米、木薯及马铃薯淀粉颗粒微晶结构及性质的研究

运用广角X射线衍射分析方法对玉米、木薯及马铃薯淀粉颗粒结晶结构及常温下水的溶胀作用对淀粉颗粒不同微晶结构的影响进行了系统研究,提出了在淀粉颗粒中存在着大量的介于微晶和非晶之间的亚微晶结构,并提供了在一条X射线衍射曲线图中确定微晶、亚微晶和非晶区域的方法。     

紫薯淀粉结构与理化性质研究

目的 了解紫薯淀粉的结构和理化性质。方法 利用碱提取法从紫薯中提取淀粉, 与普通玉米淀粉进行对比, 分别对淀粉结构(分子链结构、结晶结构等)和理化性质(透明度、凝沉性、冻融稳定性、热稳定性)进行研究。结果 紫薯淀粉直链含量(24.5%)比玉米淀粉(26.7%)低, 两者均为A型结晶结构, 但紫薯淀粉的结晶度和分子有序程度比玉米淀粉高; 紫薯淀粉糊的透明度高于玉米淀粉糊, 且随时间延长其透明度下降程度比玉米淀粉糊低; 紫薯淀粉糊不易发生凝沉现象, 但其析水率(21.4%)比玉米淀粉糊高, 即冻融稳定性弱于玉米淀粉糊; 此外, 紫薯淀粉部分结构的热稳定性大于玉米淀粉。结论 紫薯淀粉在分子链结构和结晶结构上与玉米淀粉有较小差异, 但在理化性质上与玉米淀粉差别较大, 可为其工业应用提供指导基础。     

成熟度对渝甜糯玉米淀粉颗粒形态及理化特性的影响

以不同成熟度渝甜糯玉米为材料,采用扫描电子显微镜、X射线衍射仪、傅里叶红外光谱仪、差示扫描量热仪、布拉班德黏度仪等考察成熟度对渝甜糯玉米淀粉颗粒形态和理化特性的影响。结果表明：渝甜糯玉米淀粉颗粒形状为圆形和多角形,随着成熟度的增加,多角形颗粒的数量逐渐增多;渝甜糯淀粉为A-型结晶淀粉,其2θ在15.15°、17.50°、23.00°附近,随着成熟度增加,淀粉结晶晶粒的X衍射强度增大,淀粉结构由吡喃型α-型葡萄糖构成;成熟度对渝甜糯玉米淀粉相变起始温度(To)、相变高峰温度(Tp)、相变终止温度(Tc)和相变热焓(ΔH)的影响不大,To在70.00～72.00℃范围内,Tp在74.90～76.80℃范围内,Tc在80.90～83.40℃范围内;布拉班德黏度曲线显示,授粉后25d采收的渝甜糯玉米淀粉峰值黏度最大,授粉后23d采收的渝甜糯玉米淀粉糊的热稳定性较好,以授粉后30d采收的渝甜糯玉米淀粉的冷稳定性最好。     

超高压辅助制备醋酸酯淀粉结构性质研究

以玉米淀粉为原料,乙酸酐为反应试剂,NaCl为反应介质,采用超高压辅助制备醋酸酯淀粉,利用光学显微、X-射线衍射、快速黏度分析技术对醋酸酯淀粉结构性质进行分析。研究表明,颗粒态醋酸酯淀粉结晶类型与原淀粉相同,当处理压力为600 MPa时淀粉糊化,颗粒结构被破坏,A型结晶向V型结晶转换,但糊化并不利于醋酸酯淀粉取代度的增加。适量NaCl的添加有利于超高压处理时淀粉颗粒态的维持,因而有效提高了醋酸酯淀粉的取代度。当NaCl溶液浓度为1.0%、乙酸酐添加量为2.0%、压力为400MPa时,所制备的醋酸酯淀粉取代度达到最大值(0.090),且表现出较高的峰值黏度(400.00cP)。     

Granular Structure and Physicochemical Properties of Starches from Amaranth Grain

The granular structure and physicochemical properties of starches isolated from grain amaranth cultivar K112 (Amaranthus cruentus L.) were studied in this study. Detailed physical and chemical analyses were performed by determining the granular morphology, crystallinity, particle size, thermal characteristics, blue value, enzyme susceptibility, and pasting properties. Results showed polygon-shaped A. cruentus L. K112 starch granules. The average diameter was 1.38 μm, in which half of the diameter was <2.91 μm. An A-type X-ray diffraction pattern was revealed with intense peaks of 15.2°, 17.5°, and 23.2°. The peak viscosity was 181 BU and the breakdown value was 2 BU. Amaranth starch obtained the highest pasting temperature (70.7°C) and enzymatic digestibility (absorbance value = 0.41 ± 0.013) compared with corn, cassava, and sweet potato starches.     

Microstructural and physicochemical properties of heat-moisture treated waxy and normal starches

Starches from normal rice (21.72% amylose), waxy rice (1.64% amylose), normal corn (25.19% amylose), waxy corn (2.06% amylose), normal potato (28.97% amylose) and waxy potato (3.92% amylose) were heat-treated at 100 °C for 16 h at a moisture content of 25%. The effect of heat-moisture treatment (HMT) on morphology, structure, and physicochemical properties of those starches was investigated. The HMT did not change the size, shape, and surface characteristics of corn and potato starch granules, while surface change/partial gelatinization was found on the granules of rice starches. The X-ray diffraction pattern of normal and waxy potato starches was shifted from B- to C-type by HMT. The crystallinity of the starch samples, except waxy potato starch decreased on HMT. The viscosity profiles changed significantly with HMT. The treated starches, except the waxy potato starch, had higher pasting temperature and lower viscosity. The differences in viscosity values before and after HMT were more pronounced in normal starches than in waxy starches, whereas changes in the pasting temperature showed the reverse (waxy > normal). Shifts of the gelatinization temperature to higher values and gelatinization enthalpy to lower values as well as biphasic endotherms were found in treated starches. HMT increased enzyme digestibility of treated starches (except waxy corn starch); i.e., rapidly and slowly digestible starches increased, but resistant starch decreased. Although there was no absolute consistency on the data obtained from the three pairs of waxy and normal starches, in most cases the effects of HMT on normal starches were more pronounced than the corresponding waxy starches.     

Effect of cooking time and ingredients on the performance of different starches in white sauces

The effect of white sauce ingredients and increased cooking time at 90 °C on the degree of gelatinization of corn, waxy corn, rice, potato and modified waxy corn starches was studied. The changes in pasting properties, linear viscoelastic properties, and microstructure were determined. In all the native starches in water, a longer cooking time at 90 °C caused greater starch granule swelling and more leaching of solubilized starch polymers into the intergranular space. These effects were more noticeable in the waxy corn and potato starches. The potato starch was the most affected, with complete disruption of the starch granules after 300 s at 90 °C. The microstructural changes which transformed a system characterized by starch granules dispersed in a continuous phase (amylose/amylopectin matrix) into a system with an increase in the continuous phase and a decrease in starch granules were associated with a decrease in system viscoelasticity. The elastic moduli were higher in the sauce than in the starch in water system. However, with the exception of potato starch, the white sauce showed lower viscoelasticity than the starch in water system. The white sauce ingredients decreased the effect of cooking time on the starch gelatinization process, particularly in potato starch.     

超高压处理对玉米淀粉结构及糊化特性的影响

利用光学显微、X-射线衍射、差示扫描量热、快速黏度分析技术研究了超高压处理对玉米淀粉结构及糊化性质的影响。结果显示,超高压处理能使玉米淀粉糊化,处理压力为500 MPa及600 MPa时完全糊化所需保压时间分别为15 min和5 min,但400 MPa超高压处理30 min也不会使淀粉糊化。超高压糊化过程中,淀粉颗粒结构逐渐破坏膨胀,结晶结构由A型向V型转化,RVA黏度曲线峰值黏度逐渐消失。适宜条件的超高压处理对淀粉颗粒同时具有韧化和晶体破坏作用。其中,400 MPa超高压处理5~10 min时,淀粉颗粒内部韧化作用占优,因而表现为相对结晶度、糊化温度(T_o,T_p)及糊化焓增加,而RVA曲线峰值黏度降低。     

复合酶法改性糯麦A-、B-型淀粉及对其结构和消化特性的影响

以从糯麦淀粉中分离所得的A-、B-型淀粉为研究对象,并以此作为受体,高直链玉米淀粉为供体,利用普鲁兰酶和分支酶协同处理对糯麦淀粉进行改性,测定其颗粒形态、结晶结构以及表观直链淀粉含量、溶解度、膨胀力等理化性质,并对其消化特性进行考察。结果表明：采用普鲁兰酶和分支酶两种复合酶法改性的糯麦A-、B-型淀粉,其预测血糖指数显著降低,表观直链淀粉含量显著增加、溶解度随着温度的增加而变大,膨胀力随着温度的增加基本保持不变。采用扫描电子显微镜观察到酶法改性后的淀粉颗粒形态出现孔洞结构,利用X射线衍射和傅里叶红外光谱分析相对结晶度和1 047 cm－1/1 022 cm－1处的比值可得,复合酶改性淀粉的长程有序结构和短程有序结构显著改善。通过普鲁兰酶预处理后再用分支酶改性,对糯麦A-型和B-型淀粉进行结构修饰,能够显著改善其消化特性。     

Morphological,thermal, rheological and noodle‐making properties of potato and corn starch

A comparison between the morphological, thermal, rheological and noodle‐making properties of corn starch and potato starches separated from five different potato cultivars was made. The granule size and shape of all starches differed significantly. Potato starch granules were comparatively larger than corn starch granules, while the transition temperatures were found to be higher for corn starch. Consistency coefficients and flow behaviour indices measured by back extrusion were higher for potato starches than for corn starch. Stickiness of cooked starch pastes was observed to depend upon their consistency coefficient. The gels made from all potato starches showed higher gel strength than those from corn starch. The gel strength of starches from both corn and potato increased during refrigerated storage. The amylose content, swelling power, solubility and light transmittance values of potato starches were significantly higher than those of corn starch. Noodles made from potato starches had higher cooked weight and cooking loss than corn starch noodles. Texture profile analysis revealed that potato starch noodles also had higher hardness and cohesiveness than corn starch noodles. Hardness of cooked noodles from all starches increased and cohesiveness decreased during storage. Noodles made from starches of higher viscosity exhibited higher hardness and cohesiveness. Textural differences among cooked starch noodles appeared to be associated with morphological, thermal and rheological properties of corn starch and potato starches. © 2002 Society of Chemical Industry     

红缨子高粱淀粉分子结构及糊化特性研究

分别采用扫描电镜、X射线衍射及傅立叶变换红外光谱（FTIR）分析茅台酒酿造专用高粱红缨子淀粉的颗粒结构,采用离子色谱分析其支链淀粉链长分布特征,采用差示扫描量热仪、快速黏度仪及流变仪分析其淀粉糊化特征。结果表明,红缨子高粱淀粉颗粒大小介于5～20 μm,部分颗粒表面有凹陷或呈蜂窝状;淀粉颗粒晶体结构为A型,结晶度为31.0%,淀粉颗粒表面结构的有序性比水稻、马铃薯等其他淀粉高;支链淀粉含有较高的fb3长链组分;在低温及高频率条件下,其动态模量相对较高;另外,红缨子高粱淀粉拥有较高的糊化温度和糊化吸收热焓值,具备高崩解值和低回生值等适宜酿酒的重要特征。     

LIPIDS OF WHEAT, CORN AND POTATO STARCH

The lipid constituents from wheat, corn and potato starches were analyzed, as was the composition of nonstarch compounds present in these lipid extracts. The lipids were extracted from starch granules using n- propanol-water (3:1, v/v) via cold and hot extraction into surface and internal lipid fractions, respectively; fatty acid profiles of the fractions so obtained were then carried out. The content of surface lipids was greatest from potato and wheat starches, whereas cornstarch was characterized as having the highest relative percentage of internal lipids. Hot extraction resulted in an increase in the lipid content for all extracts, and of the starches investigated, the lipids from cornstarch contained the highest percentage of polyunsaturated fatty acids. Unlike that of wheat starch, it was noted that the fatty acid, C20: 1 (n-9), could only be extracted from corn and potato starch granules by the hot extraction technique. Lysophosphatidylcholine (LPC) and some phenolics were found to bind to wheat starch granules, but not to those of corn and potato. Using HPLC-UV-DAD analysis, five phenolic compounds were detected in the lipids extracted from wheat starch by hot extraction. Maxima from UV-DAD spectra of the compounds were observed at a wavelength of 337.4 or 332.7 nm, and are characteristic of phenolic acids or their derivatives.     

嗜冷普鲁兰酶制备玉米抗性淀粉工艺优化及其表征

以玉米淀粉为原料,采用嗜冷普鲁兰酶脱支处理和压热处理相结合的方式制备玉米抗性淀粉,考察了玉米淀粉乳质量分数、耐高温α-淀粉酶添加量、嗜冷普鲁兰酶添加量、嗜冷普鲁兰酶作用时间对抗性淀粉得率的影响,采用正交试验对压热-酶解法制备玉米抗性淀粉的工艺参数进行了优化。采用扫描电子显微镜、X-射线衍射和差示扫描量热仪对玉米抗性淀粉形貌、晶体结构、热特性进行了观察与分析。结果表明,制备玉米抗性淀粉的最佳工艺条件为：玉米淀粉乳质量分数18%、耐高温α-淀粉酶添加量7 U/g、嗜冷普鲁兰酶添加量10 U/g、嗜冷普鲁兰酶作用时间9 h。在最佳条件下,玉米抗性淀粉得率为16.84%。玉米淀粉经复合酶法处理后,抗性淀粉形成了致密的层状晶体结构,表面形态结构呈现出不同于玉米原淀粉A型晶体结构的V型晶体结构;玉米抗性淀粉的起始温度、峰值温度、终止温度和相变焓值分别为117.07、140.69、153.03 ℃和1 858.12 J/g,均高于玉米原淀粉。     

超声处理对马铃薯淀粉结构特性及理化性质的影响

为了研究超声对马铃薯淀粉微观结构及理化性质的影响,以马铃薯淀粉为原料,通过扫描电子显微镜、激 光共聚焦显微镜、X射线衍射、傅里叶变换红外光谱、差示扫描量热法、快速黏度分析、偏光显微镜观察等方法, 研究了超声对马铃薯淀粉微观结构及理化性质的影响,揭示超声对马铃薯淀粉的机械力化学效应。结果表明：由于 马铃薯淀粉颗粒内部“狭长的脐点区”结构比较疏松,超声处理对马铃薯淀粉可产生显著机械力化学效应;随着超 声时间延长,马铃薯淀粉颗粒内部依次经过受力阶段、聚集阶段、团聚阶段;同时由于超声处理引起了马铃薯淀粉 颗粒结构变化,故导致了马铃薯淀粉理化性质显著变化。