微波辐射对木薯淀粉性质影响

研究微波辐射前后木薯淀粉物化性质变化,采用微波对30%水分含量木薯淀粉进行处理,结果表明,微波处理增强对应X–射线衍射峰强度,降低膨胀度、溶解度和冻融稳定性;木薯淀粉经处理后糊化起始温度升高、粘度降低,但其粘度曲线不改变。以上数据表明,在淀粉颗粒内无定形区和结晶区直链淀粉与直链淀粉、直链淀粉与支链淀粉发生交互作用,微波处理使淀粉分子发生一定程度降解。     

微波湿热处理对马铃薯抗性淀粉含量及性质的影响

在湿热条件下,采用不同微波条件对马铃薯淀粉进行处理,运用扫描电子显微镜、布拉本德粘度仪,对微波处理前后的物化性质进行了研究.结果表明,经微波辐射处理后,淀粉颗粒表面会出现小孔和凹坑;马铃薯淀粉中抗性淀粉和直链淀粉的含量、糊化转变温度及其范围、热糊稳定性和凝沉性得到提高;马铃薯淀粉的膨胀度、溶解度和粘度降低.     

马铃薯淀粉介电处理理化性质研究

以马铃薯淀粉为原料,研究射频和微波加热对马铃薯淀粉的颗粒形态、内部结构、直链淀粉含量、溶解度和膨胀度、热特性和黏度特性的影响。结果发现:淀粉经微波处理比经射频处理使淀粉表面更粗糙,压痕凹陷也更多。射频处理后直链淀粉含量高于微波处理后的淀粉。而微波处理后淀粉颗粒的体积平均粒径均大于射频处理后的体积平均粒径。射频处理改变了淀粉的晶型且结晶度降低,微波处理晶型不变,但结晶度增加。射频处理后淀粉溶解度和膨胀度高于微波处理。淀粉糊化温度:微波处理过的淀粉原淀粉射频处理过的淀粉。射频处理过的淀粉峰值黏度始终高于微波处理过的淀粉。射频处理的淀粉崩解值高于微波处理。     

微波处理对莲子淀粉理化性质的影响

为探讨微波处理对莲子淀粉的改性作用,本文利用微波工作站对莲子淀粉进行加热处理,观察预处理后的淀粉颗粒形态变化、后期糊化过程中直链淀粉溶出量和流变特性,结果表明,30%的莲子淀粉乳经不同微波功率处理后,其颗粒形态未发生明显变化,仍呈现光滑的椭球状;随着微波功率的增强,颗粒间出现了明显的聚集粘结行为,颗粒的平均粒径最大值可达26.37μm,为原淀粉2.15倍,同时淀粉颗粒晶区比例增大,995/1024吸收峰比值由0.89上升至0.99;经微波处理后的莲子淀粉,其淀粉糊的直链淀粉溶出量由120mg/g下降至87.89mg/g,淀粉糊触变性、流变粘度及弹性模量也均有降低。这说明微波处理可促使莲子淀粉拥有更紧密的晶区结构,并在后期的糊化过程中,对淀粉颗粒膨胀可能起到了一定的抑制作用,造成直链淀粉溶出量减少,从而导致淀粉糊流变特性发生变化。     

湿热处理对马铃薯淀粉超高压糊化的影响

目的 研究湿热处理对马铃薯淀粉超高压糊化的影响。方法 将经过不同时间湿热处理的样品进行不同压力的超高压处理, 采用偏光显微、X射线衍射、差示扫描量热、快速粘度分析等技术对马铃薯淀粉样品颗粒形貌、结晶结构、糊化特性热特性进行研究。结果 湿热处理增加了马铃薯淀粉的相对结晶度及糊化焓值, 提升了糊化温度。同时通过改变淀粉颗粒内部结构, 引起淀粉分子吸水性降低, 进而导致淀粉膨胀性变差, 粘度降低, 粘度曲线由A型向D型转变。无论湿热与否, 淀粉在400~600 MPa超高压处理过程中, 其相对结晶度、糊化焓值均降低, 但与原淀粉相比, 湿热处理后淀粉在超高压处理过程中相对结晶度和糊化焓值降低程度减小。结论 马铃薯淀粉水分含量为30%(m:m)时, 90 ℃湿热处理5~15 h导致淀粉颗粒内部结构更为致密, 增加其压力抵抗性, 延缓了超高压糊化过程。     

六种处理方式对慈姑淀粉理化性质的影响

为了提高慈姑淀粉的利用率，采用微波、苹果酸、盐酸、三偏磷酸钠、α-淀粉酶、乙酸酐6种不同改性方法对慈姑淀粉进行改性，并对改性后淀粉的理化特性进行了分析。结果表明：与原淀粉相比，6种处理后的慈姑淀粉均属于A型晶体结构；微波处理后的慈姑淀粉颗粒抱团成为较大颗粒，直链淀粉的相对含量增加，透明度、析水率、溶解度和膨胀度均低于原淀粉；苹果酸处理的慈姑淀粉颗粒破碎明显，透明度及膨润度降低，溶解度和直链淀粉相对含量升高；盐酸处理的慈姑淀粉颗粒出现凹坑和空洞，直链淀粉相对含量增加，凝沉性、析水率及糊化峰值温度提高，淀粉中有基团—Cl接入；三偏磷酸钠处理的慈姑淀粉颗粒出现裂纹，透明度、溶解度及膨润度降低，其糊化特性温度和焓值升高，羟基发生缔合明显；α-淀粉酶处理的慈姑淀粉颗粒表面粗糙，出现大量的凹陷，凝沉性和透明度升高，直链淀粉的相对含量降低，1 047/1 022的比值比原淀粉大，其结构更加短程有序；乙酸酐处理的慈姑淀粉颗粒表面部分出现孔洞，晶型结构没有发生改变，直链淀粉相对含量、溶解度和透明度升高，膨润度降低。综上，不同的处理方法对慈姑淀粉的理化性质影响不同，根据应用需求，可选择对应特性的改性慈姑淀...     

微波对板栗淀粉结构和理化性质的影响

为探讨微波辐照对板栗淀粉颗粒结构和理化性质的影响,采用微波辐照板栗淀粉,通过扫描电镜(SEM)、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)、差示扫描量热仪(DSC)等研究微波处理不同时间后板栗淀粉的颗粒结构和理化特性。研究表明:与原淀粉相比,微波处理后板栗淀粉的微观形貌发生明显变化,但淀粉颗粒仍为C型晶体。随着微波处理时间的增加,直链淀粉含量增大,淀粉颗粒表面出现裂纹、孔洞和黏结越显著,淀粉颗粒的相对结晶度降低、红外光谱(1 047/1 022)cm~(-1)峰强度比值降低;淀粉膨胀度和透光率也随微波处理时间的增加而降低。DSC分析表明,微波处理80 s的淀粉相转变温度(T_o和T_p)降低、糊化焓(ΔH)减少。表明微波辐照对板栗淀粉的颗粒结构和理化特征均有显著影响。     

湿热处理对不同淀粉理化特性的影响

以普通玉米淀粉、高直链玉米淀粉、马铃薯淀粉和绿豆淀粉为试验材料,研究湿热处理对不同淀粉颗粒形貌、颗粒大小、糊化特性以及抗消化特性的影响。结果表明,在淀粉乳水分含量为30%,在120℃处理湿热处理10h,不同来源的淀粉,其颗粒形貌变化不同,其中普通玉米淀粉和高直链玉米淀粉的部分颗粒间发生粘结,少许淀粉颗粒中出现了较小的颗粒,淀粉表面有较大的凹坑;马铃薯淀粉和绿豆淀粉部分颗粒形态发生变化,颗粒的脐点处出现凹坑、部分淀粉颗粒有破碎;但湿热处理前后淀粉的偏光十字没有明显变化。与原淀粉相比,不同来源淀粉经过湿热处理后淀粉糊的溶解度、膨胀度和透明度均降低,降低幅度因淀粉种类的不同而有差异。湿热处理能够提高抗性淀粉含量。湿热处理后淀粉的糊化特性发生变化,糊化温度升高,峰值黏度、低谷黏度和破损值降低。普通玉米淀粉和绿豆淀粉的最终黏度和回生值下降,马铃薯淀粉的最终黏度和回生值增大。     

过热蒸汽改性典型晶型淀粉的理化性质研究

以玉米淀粉(A型)、马铃薯淀粉(B型)和豌豆淀粉(C型)等3种典型晶型淀粉为对象,分析比较过热蒸汽短时间处理改性淀粉的颗粒形貌、粒径、热焓特性、糊化特性及结晶特性。结果表明,通过改性处理,3种晶型淀粉相对结晶度均极显著降低(P0.01),玉米淀粉晶型由A型转变为A+V型,马铃薯淀粉、豌豆淀粉的晶型分别由B型、C型转变为A型;改性的玉米、马铃薯、豌豆淀粉颗粒发生膨胀,粒径极显著增大(P0.01),糊化温度升高,糊化焓极显著减小(P0.01),淀粉糊化的稳定性和抗剪切性能明显增强。3种改性淀粉的理化性质存在较大差异。相对结晶度和晶型是导致改性淀粉性质差异的主要原因。     

不同物理方法处理对碎米中淀粉特性的影响

采用挤压、微波、超声波三种物理方法对水分含量18%的碎米淀粉进行处理,研究分析碎米淀粉经物理方法处理前后的理化性质和结构变化。结果表明,碎米淀粉经微波和超声处理后酶解力增加,糊化黏度下降,而溶解度、膨胀力、糊化温度和直链淀粉含量变化不显著;两种淀粉颗粒表面棱角减少,淀粉颗粒晶型基本没有发生变化,淀粉结晶区降低。挤压后的碎米淀粉变化较大,颗粒形状为片状,凝沉性强,1.0 h后体积仅为3 mL,糊化温度明显降低至55.0 ℃,直链淀粉含量增长为30.75%,溶解度强,为0.59%,酶解力达到45%,X-射线主要衍射峰的强度降低。     

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.     

Effects of sodium dodecyl sulphate and sonication treatment on physicochemical properties of starch

Effects of sodium dodecyl sulphate (SDS) and sonication treatment on physicochemical properties of starch were studied on four types of starch, namely, corn, potato, mung bean, and sago. The SDS and sonication treatments caused a significant reduction of protein content for all the starches. The SDS treatment did not cause apparent damage on granular structure but sonication appeared to induce changes such as rough surface and fine fissures on starch granules. The combination of SDS and sonication increased amylose content for all starches. This could be attributed to the removal of surface protein by SDS and structural weakening by sonication which facilitated amylose leaching from swollen starch granule. The X-ray pattern for all starches remained unchanged after SDS treatment, suggesting no complexation of amylose–SDS had occurred. Combined SDS-sonication treatment increased swelling and solubility of corn, mung bean, and potato starch. The treated starches showed significant increase in peak viscosity with reduction in pasting temperature, except for potato starch. Results of the present study indicate the possibilities of exploring SDS and sonication treatments for starch modifications.     

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.     

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。     

Effects of microwave heat-moisture treatment on properties of waxy and non-waxy rice starches

Waxy and non-waxy rice starches adjusted to 20% moisture (wet basis, w.b.) were heat-moisture treated in a microwave oven to determine the effects of the microwave heating characteristics on digestibility, pasting, and morphological properties of the heated starches. Microwave heating produced only minimal changes in digestibility as well as the physical characteristics of heated starches. Significant changes in viscosity properties after microwave heat treatment were observed for both waxy and non-waxy starches heat-treated in a microwave oven, relative to non-treated samples. Non-waxy starch heated in microwave oven showed an increase in breakdown viscosity from 29.8 RVU (non-treated starch) to 35.8 RVU after heating for 60 min. However, for waxy starch, breakdown viscosity decreased from 112.7 to 35.9 RVU after 60 min of microwave heat treatment, reflecting an increased stability of microwave heat-treated starch under cooking. The data obtained in this study indicate that there was much higher re-aggregation of starch granules in waxy starch after microwave heat treatment than occurred in non-waxy starch, suggesting a re-association of amylopectin branch chains in the heat-treated waxy starch.     

微波对玉米淀粉结构及理化性质的影响

本实验采用微波（累积能量值为1 680 J/g）处理不同的淀粉-水体系,观察淀粉颗粒形态的变化,并测定透明度、沉降物体积、吸水率、持水性、相对结晶度和流变特性等指标。结果表明,随着淀粉-水体系中水分质量分数的增加,淀粉颗粒的完整性和偏光十字逐渐减弱;与玉米淀粉相比,微波处理淀粉乳透明度、沉降物体积、吸水率和持水性明显增加;X射线衍射图谱表明微波处理后淀粉颗粒仍为A型而相对结晶度下降,说明微波处理破坏了淀粉的结晶结构;微波处理没有改变淀粉乳流体的类型,弹性模量均大于黏性模量,表明均以弹性性质为主。结论：微波处理淀粉-水体系对淀粉的颗粒结构和理化特征均有显著影响,本研究结果可为开发具有独特理化性质的改性淀粉或改进淀粉改性工艺提供实验与理论依据。     

微波场对玉米淀粉颗粒性质影响的研究

微波是一种能以高频的方式使物质在电磁场中加热的非电离能量.研究了淀粉经微波作用后颗粒性质的变化,结果表明,微波作用后淀粉的颗粒形貌没有发生变化,偏光十字存在,部分颗粒脐点表面出现小孔,X射线主要衍射峰的强度增大.以上数据表明微波使淀粉内部分子发生迁移形成更加有序的排列.     

Study on physicochemical characteristics of waxy potato starch in comparison with other waxy starches

The physicochemical properties of wx potato, wx corn, and wx rice starches were examined and compared. wx potato starch displayed the B‐type XRD pattern, whereas wx rice and wx corn displayed the A‐type. Shapes of wx potato starch were oval or slightly round, wx corn and wx rice starch granules were polygonal. AM contents of the three starches were between 1.0 and 1.5%. Rapid viscosity analyzer data showed initial pasting temperatures of wx potato, wx corn, and wx rice starches as 69.6, 75.4, and 76.8°C, respectively, peak viscosity, breakdown, and setback of wx potato starch were 2114, 1084, and 4 mPa s. Using DSC, onset temperature of gelatinization of wx potato starch was 5.5–7.2°C higher than those of wx rice and wx corn starches. The thermal enthalpies of the starches studied in our laboratory were in the range of 0.2268–1.9900 J/g with decreasing order of wx potato > wx corn > wx rice starch.