葛根淀粉颗粒性质的研究

本文对葛根淀粉颗粒的性质进行了研究，包括淀粉颗粒的大小、形貌、X—射线衍射图谱、α—淀粉酶的酶水解作用方式等，并与玉米淀粉进行了比较。结果表明：葛根淀粉平均粒度为24．08μm，小于玉米淀粉的38．97μm；葛根淀粉和玉米淀粉颗粒的偏光十字接近颗粒中心，但葛根淀粉颗粒的偏光十字不明显；葛根淀粉的X—射线衍射图谱为C型，玉米淀粉为A型，而两者的结晶度分别为18％和37％；葛根淀粉和玉米淀粉对α—淀粉酶的作用极为敏感，但在酶解方式上，葛根淀粉是在淀粉粒表面形成许多微孔并经脐心进入淀粉粒内部，而玉米淀粉则是被层层水解，在淀粉粒表面形成很少的微孔。     

高静压物理变性制备非晶颗粒态木薯淀粉及理化性质研究

以木薯原淀粉为原料,选择压力为300、450、600 MPa的高静压处理,保压时间为30 min,含水量为50%,制备非晶颗粒态木薯淀粉。借助扫描电镜、偏光显微镜、激光粒度分析仪、X-射线衍射仪、快速黏度分析仪、差示扫描量热仪等仪器来研究非晶颗粒态木薯淀粉的理化性质及结构性质。结果显示,600 MPa处理后的偏光显微镜照片显示颗粒的偏光十字消失,X-射线衍射仪结果显示淀粉的相对结晶度为0,木薯淀粉的颗粒结晶结构消失,扫描电镜显示淀粉仍然保持颗粒状态,则非晶颗粒态木薯淀粉的制备条件是:木薯淀粉的体积浓度50 g/100 m L,处理压力为600 MPa,处理时间为30 min;在此制备条件下得到的非晶颗粒态木薯淀粉的膨胀度为16.48%;PV、TV、BD、FV显著下降,PT、SB、Pt显著增加;剪切应力的上升速度显著加快。非晶颗粒态淀粉可以作为原淀粉的替代品制备酶降解产物和变性淀粉,黏度性质显示非晶颗粒态木薯淀粉可以应用于谷类即食粥等制品的增稠剂和抗淀粉老化剂,焙烤食品表面涂膜剂等,具有很大优势。     

非晶颗粒态木薯淀粉的结构及酶降解活性研究

采用扫描电子显微镜、光学显微镜等分析测试方法,以原淀粉为参照,对非晶颗粒态木薯淀粉的颗粒形貌以及酶降解过程进行了观察和研究,结果发现,在非晶颗粒态淀粉的侧面形成了一个大且深浅程度不同的孔洞,即爆裂孔,其位置一般位于颗粒首端脐点处,以此爆裂孔为突破口,在酶作用下,非晶颗粒态淀粉逐渐降解,直至淀粉颗粒完全消失,而原淀粉具有致密的结晶结构,在相同条件下酶降解活性远远低于非晶颗粒态淀粉。      

非晶颗粒态木薯淀粉的结构及酶降解活性研究

采用扫描电子显微镜、光学显微镜等分析测试方法,以原淀粉为参照,对非晶颗粒态木薯淀粉的颗粒形貌以及酶降解过程进行了观察和研究,结果发现,在非晶颗粒态淀粉的侧面形成了一个大且深浅程度不同的孔洞,即爆裂孔,其位置一般位于颗粒首端脐点处,以此爆裂孔为突破口,在酶作用下,非晶颗粒态淀粉逐渐降解,直至淀粉颗粒完全消失,而原淀粉具有致密的结晶结构,在相同条件下酶降解活性远远低于非晶颗粒态淀粉。     

硬脂酸木薯微晶淀粉酯性质研究及结构表征

采用微晶化和干法酯化制备硬脂酸木薯微晶淀粉酯,研究不同低取代度硬脂酸木薯微晶淀粉酯理化性质,并应用红外光谱和X-射线进行结构表征。结果表明,淀粉经复合改性后,糊粘度明显降低,凝沉性变小,透明度增加,淀粉溶解性、乳化性和乳化稳定性得到较大改善;硬脂酸木薯微晶淀粉酯在3,000～3,700cm-1处羟基伸缩振动吸收峰强度减弱,酯化反应主要发生在淀粉分子结构无定型区。     

非晶颗粒态玉米淀粉结构及酶降解活性研究

本文采用扫描电子显微镜、光学显微镜等分析测试方法，以原淀粉为参照，对非晶颗粒态玉米淀粉的颗粒形貌以及酶降解过程进行了观察和研究，结果发现，在非晶化处理过程中发生了从内向外爆裂式膨胀而形成大小、深度、位置不同的爆裂孔，以此爆裂孔为突破口，在酶作用下非晶颗粒态淀粉逐渐降解，直至淀粉颗粒的完全消失，而原淀粉具有致密的结晶结构，在相同条件下酶降解活性远远低于非晶颗粒态淀粉。     

不同链淀粉含量玉米微晶淀粉理化性质研究

分别以蜡质玉米淀粉、玉米淀粉及高直链玉米淀粉为原料,在酸醇介质中制备不同水解率微晶淀粉,测定不同微晶淀粉水解性能并研究其颗粒形貌、结晶结构、溶解度及消化性。结果表明:淀粉颗粒内部结构致密性依次减弱,支链淀粉含量高的淀粉较易被试剂进攻;经酸醇处理后,三种微晶淀粉均保留原来晶型,颗粒形态没明显变化,没破碎和膨胀出现,但颗粒表面变粗糙;随直链淀粉含量增加,相似条件(水解率和温度)淀粉溶解度逐渐降低;in-vitro消化体系中三种淀粉及其微晶淀粉消化速度依次降低。     

木薯淀粉及木薯变性淀粉性质比较研究

测定了木薯淀粉、木薯羟丙基淀粉、羟丙基交联淀粉、醋酸酯淀粉、醋酸酯交联淀粉的冻融稳定性、透光率、凝沉、耐盐性、耐酸性、糊化特性等性质。实验结果表明:经过变性的木薯淀粉和原木薯淀粉有很大的不同,经过羟丙基化、羟丙基交联、醋酸酯化、醋酸酯交联后,分别引入了羟丙基、交联键、乙酰基等,使其具有较强的冻融稳定性,具有较高的透明度、耐盐性、耐酸性。据RVA分析,各种变性淀粉糊液性质较原淀粉有较大的提高。经过交联后糊液稳定性较原淀粉、羟丙基及醋酸酯淀粉有较大程度的提高,因此具有更为广阔的应用性。      

蜡质玉米淀粉微晶的理化性质及其消化性研究

以蜡质玉米淀粉为原料,在酸醇介质中制备淀粉微晶。对制得的不同水解率的蜡质玉米淀粉微晶进行了颗粒形貌、X射线衍射、DSC热稳定性分析,溶解度和消化性能的测定。结果表明:随着酸醇水解程度的增加,淀粉颗粒形貌逐渐呈片晶状,最终为碎片;淀粉颗粒的无定形区先被水解,结晶区后被水解,进而导致颗粒破裂;晶体形态仍为A型。与原淀粉相比,淀粉微晶的Tp和Tc均增大,糊化温度范围也有很大提高;不同水解率的淀粉微晶的热焓(△H)先减小后增大。淀粉微晶的溶解度随水解率的增加不断增大。酸醇水解蜡质玉米淀粉的水解率越高,其在in vitro模型中的消化产物也就越多,消化速度也越快。对于同一水解率的淀粉微晶,其消化速度随时间的延长先上升后下降。     

木薯微孔淀粉的成孔机理研究

为微孔淀粉的工业化生产提供理论依据,利用盐酸对木薯淀粉处理制备微孔淀粉。通过SEM、DSC、XRD分析微孔淀粉的成孔机理。研究表明,酸首先作用在原淀粉颗粒表面的不规则部分以及较容易水解的无定型区,在颗粒的表面形成了浅浅的沟壑状,接着往颗粒内部进行水解,开始形成针孔状的小孔。盐酸继续纵向深入颗粒内部水解的同时,也横向的水解颗粒内部,使得颗粒内部形成中空的结构。     

修饰预糊化木薯淀粉性能研究

介绍了经化学修饰后再进行预糊化制备得到的修饰预糊化木薯淀粉的性能，并与国产预糊化木薯淀粉和泰国泰花牌预糊化木薯淀粉的性能进行了比较。结果表明：修饰预糊化木薯淀粉的性能达到且超过泰国泰花牌预糊化木薯淀粉的性能，远远优于国产预糊化木薯淀粉。     

Cassava Starch Technology: The Thai Experience

Cassava starch is an important export commodity of Thailand, about 2 × 10⁶ t are expected annually. Initially, cassava was mainly processed to meal and flour. Due to the high market demand for cassava products, the Thai cassava starch industry was established and has developed from small to large‐scale with improved processing technology. At present, a production capacity of one factory is, on average, 200 t starch per day. Transition from small to large‐scale production was accompanied by varietal development of root having high starch yield and technological improvement of starch production with shorter processing time and better starch quality. Most process technologies are still imported and adopted from those of other starches. The Thai cassava starch industry still encounters impediments, including high production cost, high resource consumption, starch loss, and adverse environmental impact especially sulfur, cyanide, solid and liquid waste. This industry continues to develop, in order to remain internationally competitive.     

Inner Structure of Potato Starch Granules

A combination treatment (dry-heat and glucoamylase) was applied on potato starch granules. Many inner granules in the granules after the treatments were observed by SEM. The inner granule located near edge of ellipsoid of granule was partially degraded X-ray diffraction pattern of starch granules did not change before and after the treatments in spite of over 50% loss by amylase digestion. GPC and iodine reaction of the sample showed the treatments brought about fairly large degradation of both amylopectin and amylose components, but GPC of debranched sample after the combination treatments showed amylose was thoroughly degraded while peaks pattern of amylopectin did not change. Small size granules were more susceptible than large size granules by the treatments.     

三氯氧磷变性木薯淀粉颗粒的显微分析研究

用扫描电镜（ＳＥＭ）和ｘ射线能谱仪（ＥＤＳ）研究了三氯氧磷变性木薯淀粉颗粒的形貌变化，对颗粒表面和内部的磷元素进行微区分析。结果表明颗粒形貌虽未变化，但不同微区的反应程度有差别，试剂先与颗粒表面发生反应，程度较高，后渗入内部，反应程度逐渐降低，液固相的淀粉化学变性为非均匀的反应。     

Pasting Properties of Potato Starch and Waxy Maize Starch Mixtures

The pasting viscosity, morphological properties, and swelling properties of potato starch and waxy maize starch mixtures at different ratios were investigated. Pasting analysis of the starch mixtures (7% solids in water, w/w) using a Rapid Visco Analyser showed linear changes in peak viscosity and pasting temperature according to the mixing ratios of both starches, but not in breakdown and setback. The pasting profile revealed that the starches rendered mutual effects during pasting, more significantly when the amounts of potato and waxy maize starches were similar. The volume fraction of swollen granules and the presence of amylose appeared to be important parameters in the mutual effects of both starched during pasting. Under a light microscope, the swelling of potato starch granules was delayed by the presence of waxy maize starch. Overall results indicate that new pasting properties can be generated by mixing starches of different botanical sources.     

Effect of Processing on Slowly Digestible Starch and Resistant Starch in Potato

The effect of a number of laboratory‐scale pretreatments on the proportions of rapidly digested (RDS), slowly digested (SDS) and resistant starch (RS) in raw and cooked potato has been examined using an in vitro digestion procedure. Potatoes of the variety Frisia were prepared in three states: raw, cooked, and cooked followed by a cold treatment (4°C, two days). Each preparation was then subjected in triplicate to freeze‐drying, coarsely mincing, pasting, freezing, dry‐milling after freeze‐drying, in 22 different combinations, before digesting. In raw potato, very little RDS and SDS (<5% total starch (TS)) were present, and the mechanical treatments of the potato did not affect the amounts of RDS and SDS. Cooking resulted in an almost complete conversion to RDS (>95% TS) in freshly‐cooked potato, but after post‐cooking cold treatment much of the RDS transformed to SDS, which reached a maximum of about 45% TS. SDS formation was independent of the degree of tissue disruption after cooking, and was generally associated with formation of RS, however, freezing after cooking allowed SDS formation without prolonged cold treatment and with very little associated RS (SDS 35% and RS 4% of TS). Freeze‐drying caused an increase in RS in most treatments of the cooked potatoes. The observed effects provided guidance for sample handling in potato research, but also suggested several approaches to the enrichment of SDS and/or RS, with a concurrent reduction in RDS, that could be used to improve the nutritional profile of potato products by decreasing RDS (lowered glycaemic impact), and increasing SDS (more sustained energy availability) and RS (prebiotic benefits).     

马铃薯淀粉双螺旋结构定量分析方法的研究

采用固体核磁共振技术(solid-state13C CP/MAS NMR)分别对天然马铃薯淀粉和无定型马铃薯淀粉进行测试并对得到的图谱进行分峰和拟合,以无定型马铃薯淀粉13C CP/MAS NMR图谱中C4在化学位移为84处的值为参考点,用Excel差减法从天然马铃薯淀粉图谱中减去无定型部分,再从得到的结晶淀粉图谱中分出由单螺旋和双螺旋结构所引起的峰,从而通过峰面积的比值计算出天然马铃薯淀粉中所含双螺旋结构的比例。     

Transformation and Balance of Cyanogenic Compounds in the Cassava Starch Manufacturing Process

The balance of total cyanogenic compounds and distribution of each compound including bound cyanide, cyanohydrin and free cyanide were evaluated in a cassava starch factory, having a production capacity around 100 t starch per day. The production of starch began with transferring washed roots to the rasper, followed by a series of extractors, separators, dewatering centrifuge and flash dryer, with an average water consumption of 11.4 t per ton dry starch. The total amount of cyanogenic compounds entering the process varied from 28 to 43 kg HCN equivalent per day, depending on the root quality. In roots, 64% of bound cyanide was primarily found and it significantly decreased to 22% after rasping whereas the cyanohydrin content increased from 34% to 62%. Most of cyanogenic compounds, predominantly present as cyanohydrin (55 to 70%), was discharged in liquid and solid wastes, accounting for 92% and 5% of total cyanide in roots, respectively. Only a negligible amount of cyanogenic compounds remained in the starch products, having less than 2 mg HCN equivalent per kilogram dry starch. Typically, water from the separators with 91% total cyanide content was recycled to the root washer before being discharged as wastewater, whereas the liquid from the coarse extractor (43% of total cyanide) was recycled to the rasper. This could cause the accumulation of cyanogen in the process and, therefore, in the finished products. With knowledge of the balance and transformation of cyanogens in starch processing, it is possible to assure the quality of low‐cyanide starch by modifying starch process features such as water circulation and pH adjustment.     

Film Formation Properties of Potato Starch Hydrolysates

Native and freeze‐dried potato starch granules were partially hydrolysed to produce maltodextrins with dextrose equivalents (DE) 10, 15 and 20. Freeze‐drying greatly improved the enzyme accessibility of the native granules. Film formation properties of the hydrolysates were examined. Films were prepared by water casting. Especially the maltodextrins, which were produced from the native starch, were very sticky materials and could not form any films. But after removing most of the soluble saccharides from the maltodextrins, good quality films were produced by dissolving the hydrolysate in water, casting on a Teflon mould and drying the solution.     

Effect of High-Pressure Homogenization on the Structure of Cassava Starch

Cassava starch suspension was homogenized at different pressures (0, 20, 40, 60, 80, and 100 MPa) with a high-pressure homogenizer. To investigate the effect of high-pressure homogenization on the structure of cassava starch, the samples were characterized using microscopy, laser scattering, and X-ray diffraction techniques, with native and heat gelatinized cassava starches as controlled samples. The temperature of starch suspension increased linearly with applied pressure at a rate of 0.187°C/MPa. Microscopy studies showed that cassava starch was partly gelatinized after high-pressure homogenization, and the degree of gelatinization increased with homogenizing pressure. Results of laser scattering measurements suggested a considerable increase in particle size after homogenization at 100 MPa as a result of granule swelling. The X-ray diffraction pattern showed that there was no evident change after homogenization suggesting that the crystalline structure of starch granules was resistant to high-pressure homogenization.