TEXTURAL PROPERTIES OF STARCH GELS FILLED WITH COLLAGEN AND CHITIN

Chitin and collagen powders were added as fillers to various starches (potato, sweet potato, kudzu, corn, wheat, and mung bean), heated at 100C for 10 min with stirring to make a hot paste and allowed to gel quiescently at 5C for 2 h in order to investigate the effects of the filler particle on the texture of the gels. The parameters of hardness, cohesiveness and adhesiveness were determined instrumentally and compared. The filler particles of collagen and chitin were effective in increasing hardness of corn starch gels but had no effects on hardness of the potato, sweet potato, kudzu, wheat and mung bean starch gels except at the lower starch concentrations. Cohesiveness was increased slightly in all starch gels by addition of collagen whereas chitin addition only increased the cohesiveness of sweet potato and mung bean starch gels. Collagen and chitin addition increased adhesiveness all of starch gels, but the intensity of the effect was most remarkable for collagen. The observed differences in effects was apparently due to differences in the interactions between starches and filler particles arising from differences in the surface properties of the filler particles.     

Equilibrium Isotherm Equations to Represent Moisture Sorption on Starch

Langmuir, Freundlich, BET, Harkins and Jura, Halsey, Smith, Henderson, and Chung and Pfost equations were used to fit experimental moisture sorption data at 20°C for kudzu, sweet potato, corn, potato, rice, wheat, and snake gourd starches. Goodness of fit (from calculated average residue), standard deviation, and standard error and range of water activity indicated Henderson and Chung and Pfost equations fitted the data well over a wide a_w range to 0.85. The large value of constants in Henderson and Chung and Pfost equations indicated stability of the microporous structure to moisture sorption. For larger constants, the microporous structures were more stable.     

Determination of Sweet Potato Starch Mixed in Kudzu Starch by Moisture Sorption Method

Moisture sorption isotherms of kudzu starch, sweet potato starch, and their mixtures were measured at 20°C by a gravimetric method with a vacuum apparatus. Correlation was found between the mixture ratio of sweet potato starch to kudzu starch and moisture content of the mixed starches at a water activity of 0.750; the correlation coefficient was 0.9955. The moisture sorption method could be used to determine the amount of sweet potato starch mixed in commercial kudzu starch.     

Moisture Sorption Characteristics of Kudzu Starch and Sweet Potato Starch

Moisture sorption characteristics of kudzu starch and sweet potato starch were investigated based on the results of moisture sorption isotherms at 11°C, 20°C and 30°C, thermal analysis, isosteric heat of sorption and entropy of sorption. The water of crystallization in sweet potato starch was strongly retained compared with that in kudzu starch. Differences in amount of moisture sorbed between kudzu starch and sweet potato starch seemed to be attributable to the stability of the microscopic structure. The interaction of moisture-sweet potato starch was stronger than that of moisture-kudzu starch. Amount of moisture sorbed and strength of moisture-starch binding of the starches, preheated to 110°C, decreased compared with those of the starches vacuum-dried at 20°C because of release of water from the amorphous part of the starch granule.     

Moisture Sorption Hysteresis in Kudzu Starch and Sweet Potato Starch

Moisture sorption hysteresis loops of kudzu starch and sweet potato starch were investigated to help understand the nature of the adsorption-desorption process. The second adsorption isotherms were above the first adsorption isotherms for kudzu starch and sweet potato starch preheated to 110°C. This was explained as an increase in the number of hydrophilic sites due to rupturing of hydrogen bonds. The hysteresis loop for kudzu starch was greater than that for sweet potato starch. This was interpreted as a difference in mesopore volume.     

淀粉种类对鲜湿面色泽及品质影响的研究

将小麦淀粉、马铃薯淀粉、红薯淀粉、豌豆淀粉及玉米淀粉添加到面粉中制作面条,从鲜湿面色泽、质构及感官三方面,研究淀粉种类对面条的影响规律。结果表明：不同淀粉均能改善鲜湿面的色泽,玉米淀粉效果最佳;质构影响方面,除红薯淀粉外,其他淀粉的添加使得面条的硬度下降,黏附性、回复性、粘聚性升高,坚实度和拉断力随添加量的增加呈先升后降的趋势;感官评价方面,玉米淀粉、小麦淀粉、马铃薯淀粉显著增大了面条的色泽得分,豌豆淀粉和红薯淀粉显著影响了韧性和粘性得分。     

常用淀粉对甘薯粉糊化特性的影响

利用Brabender粘度仪考察了几种常用淀粉对甘薯粉糊化特性的影响，认为马铃薯、甘薯淀粉使甘薯粉糊化温度降低，玉米、木薯淀粉则使其升高；甘薯、玉米淀粉使甘薯粉糊化时间延长。添加各种淀粉均可使甘薯粉的峰谷粘度提高；马铃薯、玉米淀粉还可大幅度提高其峰值粘度。但马铃薯淀粉粘度破损值大，玉米淀粉破损值小、峰谷粘度高。     

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。     

葛粉掺假的傅里叶变换红外光谱法鉴别研究

以葛粉及葛粉中分别掺假红薯粉和马铃薯粉作为研究对象,采集400～4000cm-1波数范围内的红外傅里叶变换光谱,结合主成分分析对样品的进行聚类划分。并通过Fisher判别,建立葛粉真伪的判别方程。分别以样本回判及外部验证考察模型可靠性。结果表明：葛粉、红薯粉与马铃薯粉及三者不同比例混合样品的二维主成分分布位于不同区域,且葛粉与掺假葛粉之间无重叠。判别方程经样本回判及外部验证表明,葛粉中掺假红薯粉和葛粉中掺假马铃薯粉的自身验证准确率分别为93.3%和100%;交互验证准确率分别为86.7%和92.0%。此方法具有很好的鉴别作用,可作为葛粉中掺假红薯粉和马铃薯粉的一种鉴别方法。     

On the Relationship between Specific Volume and Crystallinity of Starch

Specific volumes of starch, crystalline portion and amorphous portion are discussed and the crystallinity is calculated from the specific volume. The specific volume of starch is calculated from the density by extrapolation of the moisture content zero. The specific volumes of the amorphous portion seem to be almost the same as that of cellulose. One is 0.673 for potato, waxy corn and waxy rice and the other is 0.684 for sweet potato, tapioca, wheat and corn. The crystallinities of the starches calculated from the specific volumes with a special equation are reported.     

凉粉草胶与不同淀粉混合体系糊化和质构性质的研究

凉粉草胶(MBG)与淀粉作用可以形成凝胶。为比较不同淀粉与MBG混合体系糊化和凝胶性质的差异,选取玉米等八种常见淀粉,利用Brabender糊化仪、质构仪、对MBG与不同淀粉混合体系的糊化和质构性质进行了研究。结果发现,MBG对谷类淀粉(大米、小麦、玉米)和豆类淀粉(绿豆、豌豆)的糊化性质的影响都比较显著,对薯类淀粉(木薯、马铃薯、甘薯)的不显著,但MBG与薯类淀粉混合体系的黏度远高于MBG与豆类和谷类淀粉的;MBG与大米淀粉形成的凝胶硬度最大,与马铃薯淀粉形成的凝胶硬度次之,与豌豆淀粉形成的凝胶硬度最小。淀粉与MBG之间相互作用的强弱可以从Brabender糊化曲线上的特征点值E-D来比较。     

6种不同种类直支链淀粉相互混合对其回生的影响

目的 研究6种不同种类直支链淀粉相互混合对其回生的影响。方法 将玉米淀粉、甘薯淀粉、木薯淀粉、马铃薯淀粉、糯米淀粉、小麦淀粉等6种不同种类直支链淀粉分离出来, 然后两两混合, 研究不同直支链混合对其回生率的影响。 结果 马铃薯支链淀粉与甘薯支链淀粉以2:8(m:m)混合回生率最低, 为60.0%, 玉米支链淀粉与木薯支链淀粉以8:2(m:m)混合回生率最低为52.6%, 小麦支链淀粉与糯米支链淀粉以8:2(m:m)混合回生率最低为51.2%, 甘薯支链淀粉与小麦支链淀粉以1:1(m:m)混合回生率最低为53.7%。木薯支链淀粉与小麦直链淀粉以1:1(m:m)混合时所得淀粉回生率最大, 达到了92.0%, 混合淀粉回生后X射线晶型为B型。结论 不同种类直支链淀粉混合对其回生率影响很大, 食品加工中尽量不要混合使用木薯支链淀粉与小麦直链淀粉。     

Direct conversion of starch to hydroxymethylfurfural in the presence of an ionic liquid with metal chloride

Starch can be exploited as an abundant resource for sustainable production of diverse chemical intermediates such as hydroxymethylfurfural (HMF). We present a simple process of producing HMF from starches using an ionic liquid, 1‐octyl‐3‐methylimidazolium chloride ([OMIM]Cl), and CrCl₂ catalyst. The addition of HCl and CrCl₂ significantly affected the yields of HMF on the whole. CrCl₂ increased the yields of HMF by approximately two‐folds on average. The synthesis of HMF was most effective between 60 and 90 min reaction time at both concentrations of 0.3 and 0.5 M HCl. Starch concentration had influence on the productivity of HMF. At 20% starch concentration with 0.3 and 0.5 M HCl, its productivity was greatest (2.8 folds high). Eight starch sources (corn, wheat, rice, potato tuber, sweet potato, tapioca, acorn, and kudzu starch) were tested for the synthesis of HMF. The highest yields of HMF (73.0 ± 3.8 wt%) were obtained in tapioca starch dissolved in 0.5 M HCl.     

The Use of Potato and Sweet Potato Starches Affects White Salted Noodle Quality

ABSTRACT Potato and sweet potato starches and derivatives thereof were used to substitute part of the wheat flour in white salted noodle (WSN) manufacture. The quality of the WSN obtained was compared with the quality of WSN made from wheat flour only. When up to 20% of wheat flour was replaced by acetylated potato starch and acetylated sweet potato starches, the cooking loss of WSN decreased, while the softness, stretchability, and slipperiness increased significantly. Native and hydroxypropylated starches did not exhibit these effects. It can be concluded that the substitution of part of wheat flour with acetylated starches strongly affects noodle-making and final noodle quality, and starch substitution can be used to change the performance of a given wheat flour for noodle making in a desired way.     

SOME PHYSICOCHEMlCAL PROPERTIES OF STARCHES AS AFFECTED BY CHANGES IN ATMOSPHERIC PRESSURE

The effects of varying atmospheric pressures on the properties of starches were investigated. Four types of starches-corn, rice, potato and wheat-were studied for their water-binding capacity and viscosity behavior. Photomicrographs of starch suspensions were taken at five altitudes and temperatures of 22 °, 60 °, 70 °, 80 ° and 90 °C respectively. Measurements of the photomicrographs showed corn, potato and rice starch granules to increase in size on changing elevation from sea level to 10,000 feet. Wheat starch was not affected. Water-binding capacity increased for corn and potato starches as the altitude increased, but rice and wheat starches were not affected. The viscosity of corn, rice and wheat starch suspensions decreased initially with increasing altitudes but increased at the higher altitudes. The viscosity of potato starch suspensions did not change at increased elevations.     

Change in Digestibility of Raw Starch by Gamma-Irradiation

Irradiation effect on digestion of raw starch by glucoamylase has been investigated as a basic research for application of radiosterilization on uncooked starch fermentation. The digestibility of raw tapioca starch decreased with an increase in dose while that of other starches such as wheat, corn, sweet potato and potato were little changed by irradiation. Tapioca starch granules coagulated by irradiation and were sedimented rapidly in suspension. The coagulation of irradiated tapioca starch granules can be dispersed completely by ultrasonic treatment. These results show that the decrease in digestion of raw tapioca starch depends on the coagulation of starch granules but other factors also contribute because the recovery of digestibility by ultrasonic treatment was not complete.     

Amino Acid Additives Effects on Sweet Potato Starch Thermal Properties

This study assessed the effects of amino acid additives, aspartic acid, leucine, lysine, and methionine, on the thermal characteristics of white‐fleshed and orange‐fleshed Beauregard sweet potato starches. The orange‐fleshed sweet potato (OFSPS) starch began to gelatinize at a lower temperature (56.8°C) than the white‐fleshed sweet potato starch (WFSPS) (70.1°C), but the two starches needed the same amount of energy to gelatinize. Lysine increased the gelatinization temperature of the OFSPS. The addition of leucine, aspartic acid, and methionine had no apparent impact on the OFSPS. The addition of lysine or aspartic acid increased the gelatinization temperatures of the WFSPS. Overall, the two starches used were more affected by charged amino acids than by the neutral ones.     

Rate of Hydroxypropylation of Starches as a Function of Reaction Time

To determine the course of the hydroxypropylation reaction as a function of reaction time, waxy corn, normal corn, potato, and wheat starches were reacted with propylene oxide under normal reaction conditions. Amounts of leached material and MS values of both leached and granular molecules were determined over the course of reaction. For waxy and normal corn starches, the extent of reaction increased linearly from 0 to 12 h, after which the reaction proceeded at an ever decreasing rate, reaching zero at about 30 h of reaction. The initial rate of reaction was determined by reacting waxy corn starch with a greater amount of propylene oxide (10×normal concentration) so that there would be no slowing of the reaction due to loss of reagent. Results confirmed that the initial reaction rate was linear. The hypothesis that, as derivatization proceeds, granules are opened up, resulting in ever increasing rates of reaction was not substantiated. Amounts and MS values of leached molecules from waxy and normal corn starches increased continuously over the course of the reaction. For potato and wheat starches, MS values of the granular starch also increased continuously over the entire reaction period. Amounts of leached molecules from potato starch were greater than those from wheat starch, with the amount leached at 30 h from potato starch being slightly more than that from normal and waxy corn starches and that from wheat starch being considerably less.     

Characteristics of pores in native and hydrolyzed starch granules

Low‐temperature nitrogen adsorption and mercury porosimetry were applied for analyzing effect of α‐amylolysis upon the porosity of granules of native corn, wheat, rice, and potato starches. Specific surface area (S_BET), porosity, pore size distribution, total pore area, and mean pore radius were determined for native and digested granules. It was found that native starch granules are macroporous materials with a small participation of mesopores. In the case of native starches, the highest value of S_BET was obtained for rice starch (1.27 m²/g) and the lowest – for potato starch (0.14 m²/g). Pore size distribution curves obtained by nitrogen adsorption showed peaks in the range of diameters 2–3 nm (for all starches) and 100–200 nm (for corn and rice starches). After 60 min of enzyme action, surface area of all starches doubled in comparison to native ones. Arising of the new pores was also noted. The results of mercury porosimetry measurements showed that rice starch had the highest total area of pores and porosity but the lowest mean pore radius among all native starches. The pore size distribution curves for all starches exhibited solely one peak corresponding to the dominant group of pores of the radii in the range 0.5–8 µm, dependent on the starch source. There were also much smaller peaks situated within the range of 3–30 µm. After α‐amylolysis of corn and rice starches, the average radius of the dominant group of pores diminished. No substantial changes in the pore radii could be noted for potato starch.     

The Reactivity of Native and Autoclaved Starches from Different Origins Towards Acetylation and Cationization

Native potato, waxy corn, corn, wheat, filed pea and lentil starches were autoclaved at 15 psi, 121°C for 1min. Scanning electron micrographs of the native and autoclaved starches showed no changes in granular surfaces and shapes. In all starches, the X-ray intensities at most of the d-spacings between 3-18 Å increased upon autoclaving, being more pronounced in potato. The X-ray patterns of cereals and legumes remained unchanged, while that of tuber (potato) became more cereal-like. Differential scanning calorimetry of the starch samples revealed that autoclaving increased the gelatinization transition temperatures of wheat but decreased that of potato; the changes observed in waxy corn, corn, field pea and lentil starches were very small. The gelatinization enthalpy of all native starches decreased upon autoclaving while the percentage decrease was highly marked in potato. Image analysis of the native and autoclaved starches revealed changes in the granule size distribution patterns. Also, the population mean area of all native starch granules considerably increased upon autoclaving. Acetyl binding capacity, measured at 5% and 10% acetic anhydride addition levels, was higher in autoclaved than in native starches. Furthermore, autoclaving had no influence on starch cationization, studied at 3% and 6% reagent addition levels. The results indicated that the changes in starch molecular organization caused by autoclaving enhanced its reactivity towards acetylation but not cationization.