淀粉型甘薯RS3制备工艺及体外抗消化特性

以淀粉型甘薯为原料,利用单因素试验研究不同淀粉乳质量浓度、pH值、压热温度、压热时间及冷却回生时间对甘薯三型抗性淀粉（resistant starch type 3,RS3）得率的影响,并通过响应面设计优化制备工艺。结果显示,响应面试验得出的最优制备条件为淀粉乳浓度13%、pH5.5、压热温度110℃、压热时间35 min,此时RS3得率为37.94%,与预测值仅相差0.92%,响应面模型与实际情况拟合良好。甘薯抗性淀粉RS3的体外抗消化特性研究表明,RS3的酶解率和模拟消化道的消化率低,展示很强的抗酶解、抗消化特性。电镜结果显示,RS3颗粒呈不规则块状,表面凹凸不平;结晶型以B型为主,颗粒有序度降低,双螺旋程度和结晶度提高,与原淀粉相比结构更加紧密,这些结构特性可以解释甘薯RS3的抗消化特性。     

RS4型抗消化淀粉的结晶结构及消化性能研究

利用偏光显微、X射线衍射等现代分析技术，研究了酯化改性后淀粉颗粒形貌和结晶结构的变化。结果表明，与HylonV玉米淀粉相比，酯化改性后得到的RS4型抗消化淀粉的颗粒形貌和结晶结构都受到不同程度的破坏，尤其导致了结晶形态由B型向V型转变。由此引起淀粉的消化性能发生改变，经体外模拟试验表明，RS4型抗消化淀粉在人工胃液和人工小肠液中都有良好的抗消化性能，且随着抗消化淀粉含量的增加，抗消化性能越显著，显示了其良好的结肠靶向性。     

超微粉碎处理对木薯淀粉结构及消化特性的影响

为研究超微粉碎改性木薯淀粉及其对消化性的影响,以粒度分析、扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶红外分析(FT-IR)以及Englyst法为分析手段,研究木薯淀粉经过不同时间(0、15、30、45、60 min)超微粉碎处理后的粒度、微观结构及消化特性的变化。结果表明:木薯淀粉经超微粉碎处理60 min后,颗粒结构被严重破坏,淀粉颗粒之间发生团聚,淀粉粒径由13.50 μm增加至36.17 μm;超微粉碎处理对木薯淀粉的晶型没有影响,仍为A型,但其相对结晶度由21.33%下降至1.14%;木薯淀粉在3000~2800 cm-1与1080 cm-1处的吸收峰强度减弱,表明超微粉碎处理使木薯淀粉的结构遭到破坏,氢键相互作用减弱;天然木薯淀粉的快消化淀粉(RDS)、慢消化淀粉(SDS)、抗性淀粉(RS)的含量分别为3.91%、44.71%、51.38%,经过超微粉碎处理60 min以后,RDS与SDS的含量分别增加至6.87%和45.91%,RS的含量下降至47.21%,说明超微粉碎处理能够在一定程度上改变木薯淀粉的消化性。     

不同修饰程度对蜡质玉米淀粉理化性质和消化特性的影响

利用淀粉蔗糖酶(AS)的转糖基活力修饰蜡质玉米淀粉(WCS),探索不同修饰程度对其理化性质和消化特性的影响。结果表明:在给定的反应条件下,酶反应进程可用对数函数进行模拟;与A型的原淀粉相比,改性WCS的结构更为致密,且呈现出B型结晶特性;改性前后淀粉的支链长度分布变化显著,随着转糖基率(TR)的增加,Fr I(聚合度(DP)30)组分所占比例显著增加,Fr III(DP13)组分所占比例显著减小;与原淀粉(抗性淀粉(RS)含量=0.8%)相比,改性WCS的RS含量明显提高(53.1%≤RS含量≤73.6%),随着TR的增加,改性WCS的RS含量呈现先增加后缓慢降低的趋势,在TR=88%时,RS含量达到最高(73.6%)。     

绿豆抗性淀粉消化前后益生作用与结构变化的比较

制备与纯化得到了绿豆抗性淀粉及消化抗性淀粉,研究了它们的益生作用及结构变化。结果表明：绿豆抗性淀粉及消化抗性淀粉对双歧杆菌和乳酸杆菌的增殖效果达到100倍以上,对大肠杆菌和产气荚膜梭菌的抑制强度更是高达106倍以上,对粪肠球菌的抑制强度也有10倍,而对梭状杆菌无明显影响;它们的发酵液总酸度增大30%以上,说明它们能被肠道益生菌发酵利用;绿豆抗性淀粉经消化处理后比表面积增加,经发酵后比表面积更大。绿豆抗性淀粉的平均聚合度较之原淀粉降低了一半,发酵后绿豆抗性淀粉或消化抗性淀粉的平均聚合度继续降低30%以上;绿豆抗性淀粉经消化前后的晶型均为B型,绿豆抗性淀粉及消化抗性淀粉经发酵后,晶型都转变为A型,微晶度、亚微晶度及总结晶度较之发酵前都明显降低。     

马铃薯抗性淀粉消化前后的益生作用与结构变化

制备与纯化得到马铃薯抗性淀粉及消化抗性淀粉,研究其益生作用与结构变化。结果表明：马铃薯抗性淀粉及消化抗性淀粉对双歧杆菌和乳酸杆菌都有显著的增殖作用,对大肠杆菌和产气荚膜梭菌有强抑制作用,对粪肠球菌、梭状杆菌、兼性细菌没有影响;它们的发酵液总酸度增大,说明它们能被肠道益生菌发酵利用;马铃薯抗性淀粉经消化处理后比表面积增加,经发酵后比表面积更大;马铃薯抗性淀粉的平均聚合度较之原淀粉显著变小,马铃薯抗性淀粉或消化抗性淀粉发酵后的平均聚合度降低;马铃薯抗性淀粉经消化前后的晶型均为B型,其抗性淀粉及消化抗性淀粉发酵后的晶型都转变为A型,微晶度、亚微晶度及总结晶度较之发酵前都明显降低。     

高压处理对淀粉结构与性能的影响研究进展

作为一种新型的物理改性方式,高压处理已广泛应用于淀粉的加工和生产中。本文系统综述了高压处理对淀粉结晶结构、糊化、回生、消化、热学及流变学特性的影响。高压处理可显著降低淀粉的相对结晶度,并使淀粉A型或C型结晶结构转变为B型结晶结构。高压处理对淀粉结晶结构的破坏主要通过破坏双螺旋的规则排列实现,而不是直接破坏双螺旋结构。高压处理可提高淀粉的回生速率,并使抗性淀粉含量显著上升。高压处理提高了淀粉的表观黏度、屈服应力、储能模量和损耗模量。但高压处理对不同品种淀粉的糊化、热学性能、流动性指数和稠度系数有不同的影响趋势。高压处理技术在R3型抗性淀粉的制备及新型淀粉材料领域具有重要的应用前景。     

三相卧螺法生产小麦淀粉的颗粒形态、晶体特征和消化性能的研究

以三相卧螺法生产小麦淀粉的三种淀粉产品：A淀粉、B淀粉及副产物轻相液中的淀粉（简称轻相淀粉）为原料,对其颗粒形貌、结晶特征和消化性能进行了研究。结果表明,A淀粉平均粒径〉B淀粉平均粒径〉轻相淀粉平均粒径。三种淀粉颗粒的X衍射谱是典型的A型结构,其相对结晶度大小顺序为：B淀粉〉A淀粉〉轻相淀粉。A淀粉慢速消化淀粉（SDS）含量最高为50.14%,B淀粉抗性淀粉（RS）含量最高为32.14%,轻相淀粉快速消化淀粉（RDS）和抗性淀粉（RS）含量分别为54.39%、10.81%。结晶度与AAS呈显著正相关性（r=0.96,p〈0.05）,微晶含量与RDS呈显著负相关性（r=-0.97,p〈0.05）。     

反复冻融处理对大米RS3型抗性淀粉产率的影响

以大米淀粉为原料,采用反复冻融法制备了大米RS3型抗性淀粉,研究了反复冻融处理对大米RS3型抗性淀粉产率的影响,并优化了工艺参数。实验结果表明,大米RS3型抗性淀粉冻融法制备过程中,影响因素依次为:冻融温度结晶时间冻融次数淀粉乳浓度,而且冻融温度对大米RS3型抗性淀粉的产率影响最显著,其次为结晶时间和反复冻融次数,淀粉乳浓度影响最小。大米RS3型抗性淀粉最佳制备工艺参数:冻融温度为-18℃(解冻温度25℃)、反复冻融次数为15次、淀粉乳浓度为20%、结晶时间为48 h,在此条件下大米RS3型抗性淀粉产率最大可达14.97%。研究实验结果可为大米RS3型抗性淀粉加工提供依据。     

β-环糊精改性小麦淀粉的消化性及水解动力学

以β-环糊精对小麦淀粉进行改性,考察了β-环糊精用量、加水量、结晶温度、结晶时间对β-环糊精改性小麦淀粉的消化性和水解率的影响。结果表明:β-环糊精改性小麦淀粉的快消化淀粉(RDS)含量随β-环糊精用量的增加而减小,慢消化淀粉(SDS)含量逐渐增大,抗性淀粉(RS)含量先增大后减小。β-环糊精改性小麦淀粉制备SDS的条件为:β-环糊精用量3%、加水量80%、结晶温度25℃、结晶2 h时,生成的SDS的含量最多。水解动力学实验表明:β-环糊精改性小麦淀粉的水解率低于未改性小麦淀粉的水解率。     

Changes in smoking prevalence in Ukraine in 2001-5

Objectives

To analyse trends in smoking prevalence in Ukraine from three surveys conducted in 2001–5, and to explore correlates of observed changes, in order to estimate the stage of tobacco epidemic in Ukraine.

Design

Repeated national interview surveys in Ukraine in 2001, 2002 and 2005.

Main outcome measure

Prevalence of current smoking among the population aged ⩾15 years.

Results

The age‐standardised prevalence of current smoking in Ukrainian men was 54.8% in 2001 and 66.8% in 2005. Among Ukrainian women, prevalence increased from 11.5% in 2001 to 20.0% in 2005. ORs for yearly increase in prevalence were estimated as 1.164 (95% CI 1.111 to 1.220) for men and 1.187 (1.124 to 1.253) for women, which implies that, on average, 3–4% of men and 1.5–2% of women living in Ukraine join the smoking population each year.

Conclusions

In Ukraine, smoking prevalence is increasing in most population groups. Among men, the medium deprivation group with secondary education has the highest smoking prevalence. Among women, while the most educated, young and those living in larger cities are the leading group for tobacco use, other groups are also increasing their tobacco use. Tobacco promotion efforts appear to have been significantly more effective in Ukraine than smoking control efforts. The decrease in real cigarette prices in Ukraine in 2001–5 could be the main factor explaining the recent growth in smoking prevalence.Ukraine is a large eastern European country with high smoking prevalence. Tobacco products are widely available at very low prices, and the transnational tobacco industry is extremely successful in promoting its products and lobbying for its interests in the legislative field. Advocacy of tobacco control has only recently achieved some success in the legislative field, with the first tobacco control law being adopted in late 2005. Ukraine ratified the Framework Convention on Tobacco Control in 2006, but there is still much cause for concern regarding the enforcement and effectiveness of the adopted legislative measures. Unfortunately, the government is not yet involved in nationwide surveillance of the tobacco problem, and the available data have mostly been gathered with funding from foreign donors. Several attempts have been made to measure the extent of the tobacco epidemic in the countries of the former Soviet Union (FSU).^{1,2,3,4,5,6,7} Most of these studies have shown rather high smoking prevalence among men (50–70%) and comparatively low prevalence among women (5–20%). Most countries in the FSU have similar smoking rates, while certain trends are shown to be related to the differences in how the transnational tobacco industry succeeds in every national tobacco market.⁶ Unfortunately, few studies have been published showing trends in smoking prevalence in the FSU.⁷ In Ukraine, two studies^3,4 provided point estimates of smoking prevalence.The aim of this study was to analyse trends in smoking prevalence in Ukraine, on the basis of three surveys conducted in 2001–5, and to explore correlates of observed changes in order to estimate the stage of the tobacco epidemic in Ukraine.     

2010年河南省部分食品中重金属污染状况分析

了解河南省部分食品中重金属污染的现状。方法 在河南省18个省辖市采集8大类3 657份食品样品,按照国家标准检测食品中铅、镉和汞的含量,检测结果按照GB 2762—2012《食品安全国家标准食品中污染物限量》进行评价。结果 河南省部分食品中铅含量的平均值为0.34 mg/kg,总体超标率为8.8%(320/3 656),其中粮食、肉类和蔬菜中超标率较高,分别为17.2%(95/552)、14.5%(85/587)和10.7%(57/534);部分食品中镉含量的平均值为0.054 mg/kg,总体超标率为3.9%(143/3 657),其中食用菌和蛋类中超标率较高,分别为9.6%(49/508)和8.1%(42/518);部分食品中汞含量的平均值为0.077 mg/kg,总体超标率为8.3%(303/3 657),其中蔬菜和粮食中超标率较高,分别为25.3%(135/534)和12.3%(68/551)。结论 河南省部分食品中铅、汞污染情况较为严重,其中粮食、蔬菜和肉类食品中污染情况尤为突出,需要加强监管。     

Moulds and mycotoxins in sorghum stored in traditional containers in India

Various traditional containers have been used in India for storage of sorghum grains. Sorghum is susceptible to fungal infestation and toxin elaboration. The present study relates to the mould and mycotoxin contamination (aflatoxin B₁ and T-2 toxin) in stored sorghum in different storage containers viz. “Kotlu” (Storage rooms), earthenware pots, gunny bags and reed baskets. Aspergillus sp. and Fusarium sp. were the prominent genera and the “Kotlu” form of storage was most susceptible to fungal attack. Storage treatment had little effect on fungal contamination, but despite the fungal infestation, the mycotoxin contamination was found to be very low.     

中国固态发酵白酒中功能细菌研究进展

细菌是白酒酿造3大类微生物之一,其在白酒生产中有着重要的作用,如:芽孢杆菌、乳酸菌、放线菌和梭菌等,它们能产生酯类、有机酸、吡嗪、萜烯等微量成分,从而影响白酒的风味与品质。基于细菌在白酒中的重要功能以及微生物分离培养技术和分析检测技术的进步,近年来相关研究越来越深入。该文综述了近年来白酒功能细菌的研究进展,介绍了酿酒各个环节中主要功能细菌及其在白酒中的作用,旨在为白酒功能细菌的研究提供参考。     

Heavy metals in vegetables sold in the local market in Jordan

Heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in various vegetables (cabbage, green onion, lettuce, parsley, rocket, spinach, carrot, onion, potato and cauliflower) from the market in Jordan were measured using inductively coupled plasma-mass spectrometry. As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn ranged from 0.009–0.275 mg kg^?1 wet weight, 0.004–0.060 mg kg^?1, 0.003–0.401 mg kg^?1, 0.105–3.51 mg kg^?1, 0.15–1.15 mg kg^?1, 0.93–14.39 mg kg^?1, 0.044–0.702 mg kg^?1, 0.072–0.289 mg kg^?1 and 2.23–6.65 mg kg^?1, respectively. Parsley, followed by spinach, contained the highest concentration of heavy metals. Onion contained high levels of toxic heavy metals. The content of Cu in parsley and spinach and Pb in onion exceeded the Codex limits. However, the daily intake of heavy metals from the tested vegetables was lower than the maximum limits for allowable intake.