压热法制备白扁豆抗性淀粉的研究

研究压热法制备白扁豆抗性淀粉的工艺参数.以白扁豆淀粉为原料,采用压热法制备RS3型抗性淀粉,并通过单因素试验和正交试验,以抗性淀粉的产率作为评价指标确定抗性淀粉制备的最佳工艺参数.实验结果表明抗性淀粉制备的最佳工艺参数为淀粉糊浓度15%,pH为8,温度为125℃,时间为1.5 h,老化处理时间为36h,在此工艺条件下制...     

Varietal Differences in Surface Ultrastructure of Endosperm Cells and Starch Granules of Rice

A study was made of varietal differences in surface ultrastructure of endosperm cells and native and modified starch granules of rices. Scanning electron microscopy of the fracture face of the endosperm verified that opacity in nonwaxy rice was due to the loose arrangement of cell contents. By contrast, the endosperm of waxy rice only showed a mealy portion although it is opaque. Corrosion with HCl resulted in little change in surface structure, whereas α-amylolysis resulted in varietal differences in corrosion patterns. Waxy granules showed the fastest and most uniform pitting on α-amylolysis.     

Scanning Electron Microscopy Study on Starch Granules in Lentil Cotyledons

Scanning Electron Microscopy was used to analyze the surface changes taking place in the starch granules of lentil cotyledons during germination. In the initial germination phases, the granules exhibited a smooth surface and their interior was compact. As time progressed, the deposition of membrane-like material onto surface of the granules was seen to increase, and at 10 days their interior could be described as compartmentalized. After this it was possible to observe starch fragments with polyaedral shapes; these are thought to have originated in the interior of the granules and to have dispersed throughout the cell during their endogenous degradation.     

Purification and Properties of Lipoxygenase in Germinating Sunflower Seeds

An outline for isolating sunflower lipoxygenase (SLO) from germinating seeds is described. With linoleic acid as substrate, SLO optimum pH was 6.2, the temperature of maximum activity was 35°C and the activation energy was 3.4 Kcal/mole. Nordihydroguaiaretic acid was the most effective inhibitor of SLO, while α-tocopherol and diethyldithiocarbamic acid were less effective. Km values for linoleic acid, linolenic acid and methyl linoleate were 6.7, 5.0, and 40.0 μM, respectively. The activity of SLO was lost rapidly at temperatures higher than 50°C. The enzyme was stable when stored at ?20°C or freeze-dried, but not at 4°C in dilute solution. Experiments in micellar solution showed that SLO catalytic power was also maintained in hydrocarbon media with a Km for linoleic acid of 9 mM and a maximum velocity of 36.6 U/mg.     

烤烟催芽包衣种子试验

为了提高包衣种子的发芽率和出苗整齐度,进行了烤烟催芽包衣种子的试验.结果表明,催芽包衣种子较常规包衣种子的发芽势提高了21.7～35.8个百分点、发芽率提高了3.2～9.2个百分点.在大理州烟区催芽包衣种子可提前出苗5～7d,苗期与大田期烟株的生长势和生长整齐度均优于常规包衣种子.     

萌发荞麦种子蛋白质组分含量变化的研究

研究了荞麦种子萌发后总蛋白质和各蛋白组分如清蛋白、球蛋白、醇溶蛋白和谷蛋白的含量变化，结果表明：本试验条件下，山西甜荞和四川苦荞萌发后总蛋白质含量呈逐渐下降趋势。山西甜荞经过72h的萌发，其蛋白质总量由最初的11．90％下降到5．44％，下降了6．5个百分点。四川苦荞由萌发初的6．53％下降到0．96％，下降了5．6个百分点。荞麦清蛋白和球蛋白在萌发后均呈现下降趋势，与总蛋白质含量变化相一致。谷蛋白在萌发后至36h内含量下降，之后又快速增加。四川苦荞醇溶蛋白含量在萌发后逐渐增加．而山西甜荞则有逐渐下降趋势。     

Mechanical Behavior of Lentil Seeds in Relation to their Physicochemical and Microstructural Characteristics

The mechanical characteristics (rupture force, maximal deformation, and rupture energy) of red and green lentils under compression loading were determined as a function of moisture content ranging from 9.5 to 21.1% (w.b.). Scanning electron microscopy, laser diffraction particle size analysis, and instrumental texture evaluation were successfully applied to relate the microstructure and texture of different lentil seed varieties. Results demonstrated that all of the mechanical parameters of the green lentils, which have smaller starch granules, were significantly (p < 0.05) higher than those of the red lentils. At a loading rate of 4 mm min^?1, the force required for initiating seed rupture decreased with an increase in moisture content, for vertical and horizontal orientations (p < 0.05). The scanning electron microscopy observations also revealed that seeds were more flexible in a horizontal orientation.     

不同加工方式下芸豆子叶细胞内淀粉结构 及体外消化特性的对比分析

本研究分离出完整芸豆子叶细胞作为全食品的模型,并以芸豆淀粉为对照,研究了常压蒸煮、高压蒸煮、高温焙烤和油炸这4种热处理方式对细胞的颗粒形貌,结晶结构及体外消化动力学的影响.结果表明:高压和常压蒸煮后,芸豆细胞偏光十字显著减弱,结晶度降低约12％,无法检测到糊化峰;然而芸豆淀粉经高压和常压蒸煮后,颗粒结构被破坏,偏光十字...     

Action of Cyclodextrins on Germinating Seeds and on Micropropagated Plants

Effects of cyclodextrins on germinating barley seeds and on the growth of micropropagated strawberry plants were investigated. Treatment of barley seeds with α- or β-cyclodextrins resulted in a similar delay of germination as reported earlier [1]. The delay of germination occurred with agarose-immobilized as well as with free cyclodextrins. Since penetration of immobilized cyclodextrins into the seeds is limited, it was concluded that the delay resulted from complexation of growth factors. Soluble cyclodextrins caused a growth retardation with micropropagated strawberry plants and certain morphological changes resembling the ones observed when the action of auxins is enhanced in the respect to cytokinins.     

萌发大麦种子蛋白组分含量变化研究

采用蛋白质组分连续累进提取分析法，检测了垦啤8号、甘啤4号、Harrington、Es．terel四个品种大麦种子萌发前后各蛋白组分的含量变化。结果表明：大麦种子中清蛋白含量较低，占总蛋白含量的3％～5％，种子萌发后，清蛋白含量迅速升高，发芽第四天达到最大值，含量占10％左右，绿麦芽焙焦后，含量略有下降；球蛋白含量变化较为复杂，在种子发芽2天后达到最大值，由3％升至6％左右；醇溶蛋白在种子萌发过程中明显减少，Esterel品种变化最大，减少了总蛋白质的7．14％，其它三个品种减少了4到6个百分点；谷蛋白含量在萌发过程中略呈升高趋势，但变化不大。     

Degradation of Wheat Starch in a Single-Screw Extruder: Mechano-Kinetic Breakdown of Cooked Starch

Wheat starch was processed in a 19 mm diameter split-barrel laboratory extruder under varying conditions of barrel temperature (79–121^oC), screw speed (50, 100 rpm) and moisture content (25, 30%). Final product and samples removed from along the barrel length were examined for changes in molecular size by dilute solution viscometry. Final products were also examined for paste viscosity and estimated degree of cook. A mathematical model was developed which relates the residence time of the starch in the barrel, the nominal shear stress acting on the starch and the degree of cook of the product to the extent of molecular degradation of the starch. Solution viscometry was found to be more rapid than gel permeation methods previously used to determine the extent of molecular changes.     

Microstructure of Cotyledon Cells from Hard-to-Cook Common Beans

Two bean cultivars (FM-240 and FM-297) were seeded in the same location, harvested and cleaned. One portion was stored for 120 days under high temperature and humidity, and another was soaked in an acetate buffer (pH 4.0–4.1. 37°C) for 5 h. Hard-to-cook (HTC) defect developed in both conditions as assessed by the Mattson bean cooker. Slices of bean cotyledons were prepared to study microstructural changes as a result of the HTC condition using light and scanning electron microscopy. There were some remarkable differences in some of these changes generated by both hardening procedures. Uncooked samples hardened by storage showed smooth starch granules without any apparent deformation and somewhat similar to the control, whereas by the chemical procedure these granules were clearly deformed. Cotyledon cell separation was produced when fresh samples were cooked. Cells were smaller and separation was not as evident in HTC samples from the two procedures compared to previous fresh samples. The chemical hardening technique appeared to make more rigid the cotyledon cell structure.     

Characterization of Starch Isolated from Avocado Seeds

Starch granules of avocado seeds were oval shaped with a relatively smooth surface and an average diameter of 5–35μ. The starch was nonionic and not waxy. The gelatinization temperature range of the starch was 62–75°C. Brabender viscosity curves showed that the starch had restricted swelling with no pronounced pasting peak but with good pasting stability and average set back on cooling. Avocado seed starch exhibited type B x-ray diffraction pattern.     

Gelatinization of Starches inside Cotyledon Cells of Kidney Beans

In order to examine the gelatinization of starches inside cotyledon cells of legumes, cells were separated from kidney beans without gelatinizing starches. The solubility and swelling power of starches inside cells during gelatinization were extremely low, compared to those of isolated starches from kidney beans. The loss of birefringence of starches inside cells was also low. Differential scanning calorimetric thermogram of cells showed a biphasic endothermic transition with peaks at about 71 and 83°C, while that of isolated starches showed a single endothermic transition with a peak at about 71°C. The rupture of cells in advance resulted in the disappearance of the higher-temperature endotherm. The gelatinization of starches inside cells of kidney beans was suppressed as well as those of adzuki and faba beans.     

籽粒苋籽实中淀粉的理化性质

方法：以玉米、木薯和红薯淀粉为对照,研究实验室提取的籽粒苋K112籽实淀粉的溶解度和膨胀度、透明度、沉降曲线、冻融稳定性、老化值、淀粉糊凝胶特性和黏度。结果表明：籽粒苋籽实中淀粉含量为62.49%,其中直链淀粉含量为6.12%;其淀粉的溶解度、透明度、沉降速率低于其他3种淀粉,但膨胀度最高;冻融稳定性较差,淀粉凝胶的硬度一般,黏度较低。     

谷物中总淀粉含量的测定方法

淀粉是谷物中最重要的碳水化合物,也是决定着谷物品质和性质的重要因素。基于淀粉在食品加工业、造纸业、纺织业等领域有着广泛的应用,有必要对谷物中总淀粉含量的测定方法进行全面系统的介绍和评述。为此,笔者将总淀粉含量的测定方法分为直接测定法和间接测定法,并对其中的常用方法、标准方法、近几年发展的新方法进行了综述。     

浅谈如何及时处理粮食机械故障

介绍了粮库如何检查粮食机械故障的几点经验。首先要配备合理数量的机械、电器配件,其次是采用＂问、看、听、嗅、摸＂检查故障,以确定解决的办法。     

菠萝蜜种子淀粉提取及其理化性质的研究

以菠萝蜜种子为原料提取并纯化种子淀粉,对种子的化学组成及种子淀粉的性质进行了测定。结果表明:菠萝蜜种子含淀粉62.63%,实验室条件下种子淀粉的提取率为42.3%,菠萝蜜种子淀粉在透明度、冻融稳定性、膨胀度、低温溶解性均低于马铃薯淀粉,易老化,浓度>60 g/L的淀粉糊在90℃以上粘度较大,<70℃粘度下降并趋于稳定。     

Soluble Carbohydrates Oligosaccharides and Starch in Lima Bean Seeds

Seven genotypes of lima bean seeds at three maturity stages were analyzed by HPLC for the monosaccharide, fructose; the disaccharide, sucrose; the oligosaccharides, raffinose, stachyose, and verbascose; and the polysaccharide, starch. As maturity and size of the seeds increased, the concentrations of fructose and sucrose decreased while raffinose, stachyose and verbascose increased. No significant differences were found in the starch concentration. The concentration of the carbohydrates did not correlate with cotyledon color, seed color or growth habit. Sufficient variability existed in the oligosaccharide concentration in the investigated genotypes that reduction of the flatulence promoters (raffinose, stachyose and verbascose) might be possible by breeding.