New determination method of amylose content in potato starch

Thermal stability of potato starch depends on amylose content. Temperature at 50% mass loss from thermogravimetric analysis was used to determine the starch components. The same analysis was carried out to analyse the samples from potato, rice, wheat and high amylose. The results (26.9% of amylose content for potato, 29.1% for rice and 20.9% for wheat) were compared with results obtained from the blue value method and enzymatic method. Satisfactory compatibility for potato and rice was obtained. For such kind of samples thermogravimetric analysis can be used for amylose determination.     

淀粉可食餐具的制备及其性能测定

资源的合理利用和保护生态环境已经成为21世纪重要的课题,研究制备替代发泡塑料餐具的绿色环保可降解餐具具有重要意义。通过利用淀粉为主要原料制备环保型可食用餐具,并考察了制备样品在不同温度、PH条件下的溶解度及霉变检测不同的含水率对餐具使用性能的影响;并分析淀粉可食餐具的最佳含水率。结果表明:含水率为30%时,综合使用性能最好。     

Pore structure control of starch processed silicon nitride porous ceramics with near-zero shrinkage

Zirconium phosphate (ZrP₂O₇) bonded silicon nitride (Si₃N₄) porous ceramics were prepared using starch powder as the pore forming agent and pressureless sintering technique. The obtained results show that the porosity of the sintered starch processed 25 wt.% ZrP₂O₇ bonded Si₃N₄ porous ceramics is 36-62.3%. All the samples exhibit surprisingly low linear shrinkage. The pores are formed by the continuous reaction of ZrP₂O₇ at ~ 250 °C and burnout of starch at ~ 550 °C, during which a large amount of pores with pore sizes of less than 0.5 μm and ~ 10 μm are formed.     

Droplet deformation and break-up under shear: Hydrocolloid solution vs. suspension of starch granules

Shear induced deformation and rupture of two types of droplets, hydroxypropyl methylcellulose (HPMC) aqueous solution and modified waxy maize suspension, were studied and compared using a counter-rotating rheo-optical set-up. The motivation of the work was to explain the difference observed in flavour perception of food products thickened by these two fluids. A droplet of either fluid was placed into silicon oil and deformation and break-up were monitored as a function of applied shear stress and strain. It was found that starch suspension droplets broke up at lower deformation stress and strain than HPMC solution droplets despite viscosity ratio and capillary number suggesting the opposite. It is hypothesised that the ease with which droplets thickened by starch break-up is responsible for their rapid mixing with saliva.     

Compositional changes in whole grain flours as a result of solvent washing and their effect on starch amylolysis

Whole grain flour is used most often as raw material for fuel alcohol production. However, the dry-milling process and the non-starch components of flours may impact the enzymatic hydrolysis of starch to glucose. The particle size distributions of flours prepared from whole grain triticale, barley, wheat and corn were determined and the effects of pre-washing with water, hexane, 100% ethanol or 50% ethanol on flour composition and the amylolysis of starch were studied. Scanning electron microscopy of the flours revealed that grinding grain to pass a sieve with an aperture size of 0.5 mm effectively released starch granules from endosperm cells. Pre-washing with water or 50% ethanol decreased the protein, phytic acid and total free phenolic contents of flours and, except for corn flour, increased starch content. Pre-washing with water reduced the ash contents of all flours, and reduced the ??-glucan content of barley flour by 98%. Pre-washing with hexane or 100% ethanol removed much of the lipid from the flours. Pentosan content was affected only slightly by any of the pre-washing treatments. Each of the pre-washings was associated with a significant change, positive or negative, in the extent of ??-amylolysis for one or more of the flours. The degree of ??-amylolysis in unwashed flours ranged from 22.4 to 26.1%, and from 21.6 to 28.1% in pre-washed flours, varying with flour source and solvent treatment. Pre-washing of flours increased the degree of hydrolysis achieved with sequential ??-amylase/amyloglucosidase treatment, with values ranging from 61.4 to 72.8% in pre-washed flours compared to 56.2-57.8% in unwashed flours. The highest degrees of hydrolysis were achieved with 50% ethanol pre-washing (72.4 and 72.8% for triticale and barley flours, respectively). The degree of ??-amylase/amyloglucosidase hydrolysis obtained for isolated starches ranged from 83.7 to 93.0%. This study demonstrated clearly that the partial removal of non-starch components from whole grain flours by solvent pre-washing enhanced the degree of amylolysis of starch.     

石油工业中淀粉产品的开发和利用

许多淀粉产品用于石油工业，如黄原胶、羧甲基淀粉、预糊化淀粉和接枝淀粉等。本文介绍了这些产品的主要生产工艺和性能，以及在石油钻井、石油采集和油田污水处理等方面的应用。     

淀粉改性剂与浆料助剂分类之浅见

助剂作为浆液三大组成成分（粘着剂、助剂、溶剂）之一，能够补充粘着剂性能的不足，改善浆液的上浆性能，增进上浆效果。传统的助剂种类有九大类，现在已开发出淀粉改性剂这一新型助剂，介绍了淀粉改性剂的性能及主要技术指标，并建立了新的浆纱助剂体系，对新型助剂的性能及技术指标进行了分析、汇总。     

淀粉塑化机理研究进展

可降解淀粉塑料是目前新材料发展一个热点,由于天然淀粉热塑性差,难以直接加工成淀 粉塑料,因此淀粉塑化处理成为淀粉可降解塑料生产关键技术。本文综述淀粉的物理、化 学及热塑性改性的增塑机理,从而为共混型淀粉降解塑料或全淀粉降解塑料的生产提供 理论参考。     

Roberts铜盐法测定蔗汁葡聚糖含量的热效应——淀粉对受热蔗汁葡聚糖测定的影响

作者从研究中发现:用Roberts铜盐法测定蔗汁样本葡聚糖含量时,所得结果与蔗汁的受热有关,受热蔗汁的测定值高于真实值,作者将这种现象暂称为Roberts铜盐法测定蔗汁样本葡聚糖含量的热效应。研究表明:蔗汁中的淀粉是引起热效应的重要因素。本文最后提出了一种由淀粉引起的热效应的可行校正方法。     

Antimicrobial performance of potassium sorbate supported in tapioca starch edible films

The release and antimicrobial activity of potassium sorbate (KS) supported in tapioca starch–glycerol edible films prepared by different gelatinization/drying techniques against Zygosaccharomyces bailii was studied. Antimicrobial release in liquid media of different pHs (3.0–6.0) could be approximated to a pseudo first-order kinetic model and was almost accomplished after 30 min. Filmmaking method involving slow gelatinization and drying rate resulted in the highest fraction of KS released at equilibrium. Rate constant was higher when pH of the receiving media was 4.5 and fast gelatinization/fast drying had been used. The effectiveness of the preservative released for controlling the microbial growth depended on the pH of the receiving media, being higher at pH 3.0. No effect of filmmaking method was observed. In relation to film effectiveness as a barrier to contamination, it was observed that the preservative was available to prevent an external Z. bailii contamination and also to control yeast growth in an acidified (pH 4.5) high water activity (a _w = 0.980) semisolid product.