玉米微孔淀粉制备及其显微结构研究

以玉米淀粉为原料,研究比较酶法及酸法水解处理玉米淀粉制备微孔淀粉工艺,并借助于 扫描电子显微镜(SEM)、差式扫描量热计(DSC)、动态热机械分析(DMA)等分析手段对产品显微 结构及热相变过程进行分析。     

玉米微孔淀粉酸法制备及其特性研究

以玉米淀粉为原料,用酸水解的方法制备微孔淀粉,研究酸浓度、温度、反应时间和底物浓度对玉米淀粉成孔的影响.通过正交试验确定酸法制备玉米微孔淀粉的最优工艺条件为:酸浓度6%、温度40℃、反应时间16 h、底物浓度20%.采用扫描电子显微镜(SEM)和差示扫描量热仪(DSC)对微孔淀粉的颗粒结构和热特性进行分析,并将其与原玉米淀粉进行比较.结果表明,玉米微孔淀粉表面有凹坑或孔洞,内部有空腔,它的糊化温度范围变窄,焓变无明显变化.     

玉米微孔淀粉的制备及显微结构研究

以玉米淀粉为原料，研究比较了酶法及酸法水解处理玉米淀粉制备微孔淀粉工艺，并借助于扫描电子显微镜（scanning electron microscopes，SEM）、差式扫描量热计（diflferential scanning calorimeter，DSC）、动态热机械分析（dynamic mechanical analysis，DMA）等分析手段对产品的显微结构及热相变过程进行了分析。     

酶法制备多孔玉米淀粉及其显微结构的研究

采用α-淀粉酶和糖化酶双酶协同制备多孔玉米淀粉,研究了加酶量、反应温度、pH值、时间等因素对多孔淀粉水解率和吸油率的影响,得出制备多孔玉米淀粉的最佳条件为:加酶量1%以淀粉干基计),酶配比(α-淀粉酶:糖化酶)1:2,反应温度55℃,pH 5.0,反应时间16 h,所得多孔淀粉的水解率为53.45%,吸油率为98.48%,并借助于偏光显微镜、扫描电子显微镜(SEM)对产品的显微结构进行研究.     

酸法制备小麦微孔淀粉的结构研究

利用酸法制备小麦微孔淀粉,通过SEM(扫描电镜)、IR(红外光谱法)、DSC(差示扫描量热法)、XRD(X射线衍射)研究微孔淀粉的结构.结果表明:与原淀粉相比,微孔淀粉表面形成微型孔洞,孔径沿径向增大,且微孔淀粉分子结构未见变化.微孔淀粉DSC吸热峰的峰值温度减小,峰面积增大,结晶度增加.微孔淀粉XRD图的峰强减弱,结晶区部分水解.     

快速崩解羧甲基-交联玉米淀粉性能研究及结构表征

以玉米淀粉为原料,采用交联、醚化复合变性方法,将溶剂法与微波固相法工艺结合成功的制备了药用快速崩解剂羧甲基-交联玉米淀粉(CCMS).红外光谱仪检测显示淀粉分子上引进了羧基基团,产物为目标产物;扫描电子显微镜(SEM)检测结果显示羧甲基-交联玉米淀粉的颗粒较原淀粉粗糙,颗粒表面有小孔洞;偏光显微镜观察显示羧甲基-交联玉米淀粉的偏光十字强度较原淀粉弱,表明其晶体结构已遭到部分破坏;热分析(TGA-DTA)表明CCMS的耐热性较原淀粉、CMS差,但其热稳定性比原淀粉、CMS高.DSC分析显示,CMS和CCMS与玉米原淀粉相比,糊化温度降低;X-衍射分析显示CCMS的晶体结构受到明显破坏,而CMS的X-射线衍射强度也有减弱,表明改性不仅发生在淀粉结构的无定型区,也发生在结晶区.本试验所得的产品在常温下能快速吸水膨胀,促药片崩解性能好.     

大米抗性淀粉双酶制备及其结构表征

以大米淀粉为原料,α-淀粉酶与普鲁兰酶为酶解剂,利用单因素试验研究大米抗性淀粉的制备工艺条件;通过抗酶解试验研究了其抗酶解性;采用扫描电子显微镜(SEM)、差示扫描量热仪(DSC)和X-射线衍射(X-RD)表征了大米抗性淀粉的结构。确定最佳工艺条件为:pH 5.5、温度80℃、反应时间40 min、酶α-淀粉用量4 u/g,抗性淀粉得率为45.2%。利用抗酶解试验,通过与单酶法和湿热法制备得到的抗性淀粉相比较,发现双酶法制备的抗性淀粉具有较强的抗酶解性能,24 h时的酶解率为8.02%。DSC、SEM和X-RD分析表明:双酶解法制备所得抗性淀粉具有糊化热性能稳定、空间结构紧密以及结晶度高等特点。表明双酶法制备的大米抗性淀粉抗消化能力强。     

盐酸制备小麦微孔淀粉的性能及结构研究

利用盐酸制备小麦微孔淀粉,研究盐酸浓度、反应时间、反应温度和搅拌速度对微孔淀粉吸附性能的影响,并通过红外光谱(IR)、差示扫描量热分析(DSC)、X射线衍射分析(XRD)研究微孔淀粉的结构.结果表明:盐酸制备小麦微孔淀粉的最佳工艺条件是:盐酸浓度4.0%,反应时间16h,反应温度45℃,搅拌速度为1500r/min.通过XRD、DSC分析发现:小麦微孔淀粉的结晶部分比例增加.     

大米抗性淀粉糊化特性的研究

采用差示扫描量热分析技术(DSC)对大米原淀粉及抗性淀粉样品的糊化温度和吸热焓进行了测试和研究.差示扫描量热分析结果表明,抗性淀粉的开始吸热温度和完成温度均高于原淀粉,且吸热焓增大,说明沸水浴处理使淀粉形成了致密的结晶结构.     

嗜冷普鲁兰酶制备玉米抗性淀粉工艺优化及其表征

以玉米淀粉为原料,采用嗜冷普鲁兰酶脱支处理和压热处理相结合的方式制备玉米抗性淀粉,考察了玉米淀粉乳质量分数、耐高温α-淀粉酶添加量、嗜冷普鲁兰酶添加量、嗜冷普鲁兰酶作用时间对抗性淀粉得率的影响,采用正交试验对压热-酶解法制备玉米抗性淀粉的工艺参数进行了优化。采用扫描电子显微镜、X-射线衍射和差示扫描量热仪对玉米抗性淀粉形貌、晶体结构、热特性进行了观察与分析。结果表明,制备玉米抗性淀粉的最佳工艺条件为：玉米淀粉乳质量分数18%、耐高温α-淀粉酶添加量7 U/g、嗜冷普鲁兰酶添加量10 U/g、嗜冷普鲁兰酶作用时间9 h。在最佳条件下,玉米抗性淀粉得率为16.84%。玉米淀粉经复合酶法处理后,抗性淀粉形成了致密的层状晶体结构,表面形态结构呈现出不同于玉米原淀粉A型晶体结构的V型晶体结构;玉米抗性淀粉的起始温度、峰值温度、终止温度和相变焓值分别为117.07、140.69、153.03 ℃和1 858.12 J/g,均高于玉米原淀粉。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of     

The Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.