葛根淀粉特性及产品开发的研究

本文研究可知,葛根淀粉颗粒呈不规则园形或棱形（光学显微镜下）。在温度４５℃－９５℃范围内,淀粉色泽由乳白→白色→灰白→灰色→灰褐色,糊化温度为６５℃－７５℃。用１０％的柠檬酸在５０℃温度下处理５分钟,对葛根淀粉色泽有较好的增白作用。同时利用上述特性,初步对其淀粉进行了饮料制作及喷雾干燥试验,得到了较为理想的效果。     

不同高梁品系的淀粉糊化特征

利用差示扫描量热分析仪（DSC）和淀粉快速黏度分析仪（RVA）测定了14个高粱（Sorghumbicolor）品系的直链淀粉含量和淀粉糊化特性参数,并分析了各特征参数的变化规律及其相互关系。研究结果表明,高粱品系间直链淀粉含量存在较大差异,变幅为0．29％-29．45％;DSC分析所得糊化特性也表现出一定的差异,直链淀粉含量低的高粱品系的起始温度（To）、峰值温度（Tp）、终止温度（Tc）和热焓变化（△H）都较高：而直链淀粉含量高的高粱品系的To、Tp、Tc和△H都相对较低。不同品系的RVA谱差异主要表现在各个黏滞性特征值上,直链淀粉含量低的高粱品系的RVA谱具有较高的峰值黏度和最高的消减值：而直链淀粉含量高的高粱品系具有较低的峰值黏度。相关分析表明,直链淀粉含量和膨胀势与其它特征值间的相关性均达显著水平：峰值黏度（PV）与最终黏度（FV）、回冷恢复值、糊化时间和糊化温度间呈极显著负相关,与崩解值和消减值则呈极显著正相关。将直链淀粉含量的选择与RVA谱测定相结合,有助于提高选择的准确率,进而为高粱品质改良和育种提供理论依据。     

温度对枯草芽胞杆菌α-淀粉酶活性的影响

目的：探讨温度对枯草芽胞杆菌分解淀粉的影响,找出α-淀粉酶活性区问。方法：设淀粉实验组及无淀粉对照组。接种枯草芽胞杆菌、大肠埃希菌4组16管,空白对照、实验管4组8管,15℃、25℃、37℃、40℃温箱连续培养,测量不同时间段内pH值及酶活值,观察颜色的变化。结果：在15℃～40℃下温度越高接种管颜色、pH值、透光度变化越明显。结论：温度对枯草芽胞杆菌。一淀粉酶活性影响较大,尤其在25℃～40℃区间内分解淀粉能力很强,这为选择微生物法解决淀粉导致的水源富营养化提供了依据．也是可行的。     

黑曲霉（Aspergillus niger）和运动发酵单胞菌（Zymomonas mobilis）共固定化细胞酒精发酵的研究

本研究将生产上常用的糖化菌（Ａｓｐ．ｎｉｇｅｒ３．４３０９）与酒精产生菌（Ｚ．ｍｏｂｉｌｉｓ）共同固定在海藻酸钙凝胶中,以淀粉为原料进行固定化细胞酒精发酵实验,并就ｐＨ、温度、通气量。淀粉浓度等对发酵的影响进行了探讨,认为当ＰＨ为５．０～５．５,温度为３０℃～３３℃时乙醇产率最高（Ｙｐ／ｓ可达０．３９）。而淀粉浓度、通气量对共固定化细胞酒精发酵有显著影响,二者存在着较强的交互作用,在发酵过程中根据淀粉粘度情况调节通气量将有助于提高乙醇产率。     

莲子磨皮粉淀粉的提取工艺优化及其性质分析

磨皮粉为莲子加工过程中的副产物,本实验以莲子磨皮粉提取蛋白质后的残渣为原料,通过单因素和正交实验优化了其淀粉提取工艺,并分析了该淀粉的颗粒形貌、晶型和糊化特性等性质。结果表明,提取莲子磨皮粉淀粉的最优条件为:0.125 mol/L Na OH提取液、液固比8∶1(m L/g),在温度50℃下提取5.5 h,在此条件下粗淀粉的提取率为94.80%;所得粗淀粉中淀粉含量达88.64%,直链淀粉含量达34.97%;淀粉为C型结晶结构,颗粒多呈椭圆形,粒径范围在3~26μm;起始糊化温度为78.4℃,崩解值为2172.00 m Pa.s,较易糊化且淀粉糊热稳定性较好;回升值为2025.00 m Pa.s,易老化。     

普鲁兰酶基因在解淀粉芽孢杆菌BF7658菌株中的分泌表达

根据文献报道的核苷酸序列合成Bacillus deramificans普鲁兰酶成熟肽编码基因BdP。将BdP基因插入芽孢杆菌分泌表达载体pUC980信号肽编码区下游,获得重组质粒pUC980-BdP,重组质粒转化中温α-淀粉酶生产菌解淀粉芽孢杆菌BF7658菌株。摇瓶发酵实验表明,重组转化子发酵液有明显普鲁兰酶酶活,约48h酶活达到最高水平,为2．8ASPU／mL。酶学性质分析表明,重组酶最适作用温度约为60℃,最适反应pH为5．0,60℃保温3h仍保存50％的活性。重组酶性质适合淀粉糖化工艺的要求。     

嗜热真菌Thermomyces lanuginosus A_(236)热稳定葡萄糖淀粉酶的纯化及其特性

嗜热真菌ThermomyceslanuginosusA_236在液体培养基中50℃下静止培养14天,粗提酶液经硫酸铵分级沉淀、DEAE-Toyopearl离子交换层析、Butyl－Toyopearl疏水层析、SephacrylS100凝胶过滤和FPLCMonoQ离子交换层析,得到了凝胶电泳均质的葡萄糖淀粉酶。酶促反应产物经TLC分析为葡萄糖,证明纯化的酶为葡萄糖淀粉酶（EC3．2．1．3）。SDS－PAGE测定其分子量为72,000,不具亚基,PI为4．0,富含Val和Leu。酶反应最适温度和pH分别为70℃和5．0。在pH5．0条件下,酶在60℃保温1h,仍具有原酶活性。酶活性在70℃和80℃的半衰期分别为20min和6min。Ca2+对酶有激活作用,Fe3+、Al3+、Hg2+等金属离子对酶活力有一定的抑制作用。纯酶碳水化合物含量为12．4％。纯酶可水解可溶性淀粉、直链淀粉、支链淀粉、糊精、糖原、麦芽三糖和麦芽糖,其中可溶性淀粉为最适底物。     

不同高粱品系的淀粉糊化特征

利用差示扫描量热分析仪(DSC)和淀粉快速黏度分析仪(RVA)测定了14个高粱(Sorghum bicolor)品系的直链淀粉含量和淀粉糊化特性参数, 并分析了各特征参数的变化规律及其相互关系。研究结果表明, 高粱品系间直链淀粉含量存在较大差异, 变幅为0.29%–29.45%; DSC分析所得糊化特性也表现出一定的差异, 直链淀粉含量低的高粱品系的起始温度(T_o)、峰值温度(T_p)、终止温度(T_c)和热焓变化(ΔH)都较高; 而直链淀粉含量高的高粱品系的T_o、T_p、T_c和ΔH都相对较低。不同品系的RVA谱差异主要表现在各个黏滞性特征值上, 直链淀粉含量低的高粱品系的RVA谱具有较高的峰值黏度和最高的消减值; 而直链淀粉含量高的高粱品系具有较低的峰值黏度。相关分析表明, 直链淀粉含量和膨胀势与其它特征值间的相关性均达显著水平; 峰值黏度(PV)与最终黏度(FV)、回冷恢复值、糊化时间和糊化温度间呈极显著负相关, 与崩解值和消减值则呈极显著正相关。将直链淀粉含量的选择与RVA谱测定相结合, 有助于提高选择的准确率,进而为高粱品质改良和育种提供理论依据。     

拔节期追氮对不同季节糯玉米淀粉糊化特性的影响

明确基因型、生长环境和栽培措施对糯玉米淀粉糊化特性的影响可以调控淀粉品质。以垦粘1号、苏玉糯1号和苏玉糯5号为材料,研究了拔节期追氮量(0、150kghm-2和300kghm-2)对春季和秋季淀粉糊化特性的影响。结果表明:生长季节对淀粉糊化特性的影响大于基因型和拔节期追氮处理。秋季生长条件下的糯玉米淀粉具有较高的峰值黏度、谷值黏度、崩解值和终值黏度;拔节期适量追氮处理下糯玉米淀粉糊化特性较不追氮差异较小,但过量追氮峰值黏度和崩解值下降,糊化温度升高。相关分析表明,峰值黏度和谷值黏度、崩解值和终值黏度呈显著或极显著正相关,且峰值黏度、崩解值和峰值时间以及糊化温度呈显著或极显著负相关。以垦粘1号为材料,春季条件下生长并拔节期追施氮300kghm-2,秋季条件下生长并拔节期追施氮150kghm-2,淀粉的糊化特性较优,即具有较高的峰值黏度和崩解值。     

双孢斑褶菇菌丝体与子实体培养研究

双孢斑褶菇是一种著名的神经致幻菌物,菌丝体呈白色,具有明显的锁状联合。分类地位属于担子菌门,伞菌目,粪锈伞科。研究了C源、N源、C／N比、pH值、温度和培养料的料水比对该菌菌丝体生长的影响,及培养料的选择试验和出菇条件试验。菌丝体生长最佳的C源是淀粉、蔗糖、纤维素;酵母膏、硝酸钾、玉米粉和硝酸铵为最佳氮源;菌丝体生长对培养基碳氮比的适应比较广泛;适宜温度是5℃～35℃,最适为25℃～30℃：适宜的pH范围是4～13,最适为6．5～8．0;培养料适宜的含水量为45％～75％,最适为65％～70％。适合菌丝体和子实体生长的培养料为食用菌出菇废料、稻麦草、牛粪。子实体形成的温度是18℃～28℃,最适温度是20℃～25℃,空气相对湿度为70％～85％。子实体产量为0.1％～0.3％。     

Molecular structure of amylopectin from Amaranth starch and its effect on physicochemical properties

The molecular structure of amylopectin and its varphi,beta-limit dextrins from starch of 13 amaranth cultivars was determined by HPAEC-PAD after debranching. Chain length profiles of amylopectins showed bimodal distributions. The molar-based ratios of the average chain lengths of amylopectins (CLap) ranged from 17.41 to 18.22. The molar-based average chain lengths (CLld) and average B-chain lengths (BCLld) of varphi,beta-limit dextrins varied from 7.68 to 8.05, and from 14.10 to 14.73, respectively. Correlation analysis indicated that most structural parameters were positively correlated with thermal properties with few exceptions, whereas the content of fraction fa' ("'" stands for molar-based chain length ratio) was negatively correlated with the thermal properties. Pasting properties of cold paste viscosity (CPV) and setback were also correlated with amylopectin structural parameters.     

荔枝胚败育过程中内源激素与蛋白质含量的变化

连续3年(1999-2001年)对典型的荔枝焦核品种桂味、糯米糍和大核品种黑叶、怀枝花后10-40d的幼胚和胚乳内源激素、多酚含量及蛋白质动态变化进行研究。结果表明,焦核品种幼胚及胚乳中的IAA、GAs和ABA含量低于大核品种;多酚类物质含量在胚中低于大核品种,胚乳中则高于大核品种;胚和胚乳中的蛋白质含量均低于大核品种。蛋白质电泳结果显示,22．5、28．5和45kD这3类蛋白质在怀枝和黑叶的胚蛋白质代谢过程中表现出较高的稳定性,桂味和糯米糍胚蛋白质中的28．5kD蛋白质也有相似的特性。     

Starch modification by iterated syneresis

Potato, tapioca, corn and wheat starches were solubilised in water and isolated from the solution by iterated syneresis and the effect of this physical modification on the physicochemical properties and structure was studied. The experimental starches were examined by chemical analysis, the Brabender rheological method, scanning electron or light microscopy, X-ray diffractometry, infrared spectroscopy, and differential scanning calorimetry. Physical modification was evidenced to the change starch–water interaction and the structure of starches. Pasting temperature shifted to lower values and the gelatinisation mechanism changed. All modified starches had a B-type of X-ray diffraction pattern. The melting temperature of starch crystallites was typical of retrograded starch, but the enthalpy change was higher. The correlation between the resistant starch content of modified starches and their crystal structure was discussed together with the thermal properties.     

Physicochemical characteristics and fine structure of high-amylose wheat starches isolated from Australian wheat cultivars

High-amylose starch is a source of resistant starch (RS) which have great impact on human health like dietary fiber. Nowadays, high-amylose wheat has been produced by genetic backcrossing, which enhances apparent amylose content and generates altered amylopectin. In this study, the high-amylose wheat starches isolated from various high-amylose wheat cultivars grown in Australia were characterized for understanding their physicochemical properties and fine structure of starch. The physicochemical characteristics of the high-amylose wheat starches are significantly different among the cultivars. Amylose contents of these cultivars were in a range of 28.0–36.9%, which is significantly higher than that of the normal wheat starch (25.6%). The high-amylose wheat starches also had higher blue value but lower λ_max than the normal wheat starch. Gelatinization temperature of the high-amylose wheat starches is higher than that of the normal wheat starch but transition enthalpy is lower. X-ray diffraction showed that the high-amylose wheat starch had C-type crystals close to A-type crystal. Pasting properties of the high-amylose wheat starches were varying depending on the cultivars. However, almost high-amylose wheat starches had lower peak and final viscosities and higher setback viscosity than did the normal wheat starch. Fine structure of amylose and amylopectin was different among the high-amylose wheat cultivars and related to the physicochemical properties of starch. These results help to understand well the characteristics of the high-amylose wheat starches before application for food processing.     

Physico-chemical and morphological characteristics of New Zealand Taewa (Maori potato) starches

The physico-chemical, morphological, thermal, pasting, textural, and retrogradation properties of the starches isolated from four traditional Taewa (Maori potato) cultivars (Karuparera, Tutaekuri, Huakaroro, Moemoe) of New Zealand were studied and compared with starch properties of a modern potato cultivar (Nadine). The relationships between the different starch characteristics were quantified using Pearson correlation and principal component analysis. Significant differences were observed among physico-chemical properties such as phosphorus content, amylose content, swelling power, solubility and light transmittance of starches from the different potato cultivars. The starch granule morphology (size and shape) for all the potato cultivars showed considerable variation when studied by scanning electron microscopy and particle size analysis. Starch granules from Nadine and Moemoe cultivars showed the presence of large and irregular or cuboid granules in fairly high number compared with the starches from the other cultivars. The transition temperatures (T_o; T_p; T_c) and the enthalpies (ΔH_gel) associated with gelatinization suggested differences in the stability of the crystalline structures among these potato starches. The Moemoe starch showed the lowest T_o, while it was higher for Tutaekuri and Karuparera starches. Pasting properties such as peak, final and breakdown viscosity and texture profile analysis (TPA) parameters of starch gels such as hardness and fracturability were found to be higher for Nadine and Huakaroro starches. The Nadine and Huakaroro starch gels also had lower tendency towards retrogradation as evidenced by their lower syneresis (%) during storage at 4 °C. Principal component analysis showed that the Tutaekuri and Nadine cultivars differed to the greatest degree in terms of the properties of their starches.     

Oxidized and acid thinned starch derivatives of hybrid maize: functional characteristics, wide-angle X-ray diffractometry and thermal properties

Starch isolated from hybrid maize (8535-23) was subjected to oxidation and acid thinning. Proximate analyses revealed that moisture, ash, protein, fat, fibre, and pH reduced after oxidation and acid thinning. Percentage amylose content reduced from 20.42% in native starch to 18.76 and 17.65% in oxidised and acid thinned starch derivatives, respectively. Wide-angle X-ray diffraction patterns indicated strong peaks at 15.9 degrees, 17.2 degrees, 18.8 degrees, and 25.0 degrees 2theta. No significant difference was observed between the X-ray pattern of the native and modified starches. Both swelling power and solubility increased with increase in temperature. Oxidation and acid thinning reduced swelling power and increased solubility starch. At all pHs, both oxidation and acid thinning reduced the swelling capacity of the native starch. Oxidation increased water and oil absorption capacity of the native starch, while both hydrophilic and hydrophobic properties reduced following acid thinning. Least gelation concentration reduced in acid thinned starch but increased in oxidised derivative. Pasting temperature (Tp), peak viscosity (Pv), hot paste viscosity (Hv), and viscosity after 30 min holding at 95 degrees C (H(v30)) reduced following both modifications. However, values for cold paste viscosity (Cv) and setback (SB) reduced in oxidised derivative and increased in acid thinned starch. Light transmittance of the starch pastes reduced with increase in storage days, however, reduction was more pronounced in native and acid thinned starches. Onset temperature (To), peak temperature (Tp) and conclusion temperature (Tc) of gelatinisation reduced in modified starches compared with native hybrid maize starch. Also, gelatinisation enthalpy reduced after oxidation and acid thinning. Enthalpy of regelatinisation increased as days of storage of starch paste increased.     

Some Physico-Chemical Properties of Non-Waxy Paddy Rice Starch in Niigata Prefecture

Fifteen samples of milled rice had protein contents ranging from 5.53 to 7.83% and amylose contents ranging from 17.6 to 22.1%. Eating and cooking qualities of cooked rice gave gross palatability indicies ranging from 100 to 61, cohesiveness values by balance method from 64 to 9, and starch-iodine color test values of milled rice from 0.297 to 0.574. Pasting characteristics of a 8% suspension of rice starch gave maximum viscosity values ranging from 550 to 380 Brabender Unit (B.U.), temperature at maximum viscosity from 82° to 92.5°C, break down values from 260 to 20B.U., and set back values from ?0.5 to 60B.U. Good correlations were found between cooking and eating qualities of rice and rheological property of starch, and between rheological property and amylose content of starch, respectively.     

Pasting viscosity and in vitro digestibility of retrograded waxy and normal corn starch powders

Pasting viscosity and in vitro digestibility of oven-dried powders of waxy and normal corn starch gels (40% solids) retrograded under an isothermal (4 °C) or temperature cycled (4/30 °C) storage were investigated. Temperature cycling induced higher onset temperature for melting of amylopectin crystals than isothermal storage under a differential scanning calorimeter whereas little difference in crystalline type was observed under X-ray diffraction analysis. Temperature cycling caused higher pasting temperature and viscosity for the retrograded starches than isothermal storage. The retrograded waxy corn starch powders exhibited pasting behaviors similar to that of native waxy corn starch. However, the retrograded normal corn starch powders showed very much different pasting patterns with lower pasting viscosity but higher pasting temperature than native starch counterpart. The retrogradation increased slowly digestible starch content without changing resistant starch content, more effectively by the temperature cycling than the isothermal storage.     

Starch Mobilization in Ultradried Seed of Maize (Zea mays L.) During Germination

The effects of ultradry storage on the starch mobilization in maize (Zea mays L.) seed after aging were investigated. The results indicated that there were no significant differences in the content of ATP,starch, and soluble sugar, as well as the activity of amylase, between ultradried seeds and seeds stored at -20 ℃ during germination. These results were consistent with the higher level of vigor of the ultradried seed. Sieve tube introduction of a fluorescence dye (carboxyl fluoresceindiacetate) and laser confocal microscopy were used to study the development of plasmodesmata in the ultradried seeds. The results indicated that plasmodesmata developed well in ultradried seeds. Fluorescence analysis also showed that the fluorescence intensity in the radicle of ultradried seeds was stronger than that in seeds with a higher moisture content. This suggests that ultradry treatment has no adverse effects on the seeds. After seed imbibition, cell orgaelles could be resumed. It is concluded that ultradry seed storage is beneficial for maintaining seed vigor and that starchy mobilization proceeds regularly during germination.     

Biosynthesis of Starch in Proplastids of Germinating Ricinus communis Endosperm Tissue

Electron photomicrographs of endosperm tissue from germinating seed of Ricinus communis L. cv. Hale show proplastids which contain prominent starch grains. The content of starch in endosperm tissue increased from 500 micrograms per seed, in imbibed seed, to 1,100 micrograms per seed in 5-day-old seedlings. The maximum net rate of starch deposition was 1.1 nanomoles glucose incorporated per minute per seed. About 200 micrograms of starch remained in the endosperm 9 days after imbibition. Starch content followed the same developmental pattern as the content of sucrose, free reducing sugars, and other metabolic processes found in this tissue. Two key enzymes of starch synthesis, adenosine diphosphoglucose (ADPG) pyrophosphorylase and ADPG-starch glucosyl transferase (starch synthetase) exhibited maximum activities at 4 and 5 days after germination, respectively. The maximum activity of ADPG pyrophosphorylase was 8.17 nanomoles ADPG formed per minute per seed, whereas starch synthetase exhibited an activity of 125 nanomoles glucose incorporated per minute per seed. These levels of enzyme activity are sufficient to account for the starch synthesis observed. Other enzymes which may be involved in starch synthesis include 3-phosphoglycerate kinase which showed an activity of 8.76 units per seed, triose-P isomerase (2.56 units per seed), fructose-1,6-bisphosphate aldolase (0.99 units per seed), fructose-1,6-bisphosphatase (0.23 units per seed), phosphoglucose isomerase (12.6 units per seed), and phosphoglucomutase (9.72 units per seed). The activities of these enzymes were similar to previously reported values.

Starch synthetase was found in association with the fraction containing proplastids isolated from endosperm tissue. Of the total starch synthetase activity in the endosperm, 38% was particulate. Forty-four% of the total particulate activity of starch synthetase placed on sucrose gradients was associated with the band containing proplastids. The proplastids contained 98% of the ribulose 1,5-bisphosphate carboxylase carboxylase activity placed on the gradient.