番茄汁饮料维生素C稳定性的研究

以新鲜番茄果实为原料,研究了影响番茄汁加工和储藏过程中的维生素C稳定性的因素。结果表明:从加工过程来看,与正常清洗和慢速清洗相比,快速清洗方式更有利于保存番茄果中的维生素C;30%火力微波热烫60 s较热水热烫的维生素C保存率高;热榨较冷榨更有利于保持番茄汁中的维生素C的含量;添加剂的添加量对维生素C含量的影响采用L9(34)正交试验设计,其中,蔗糖对维生素C的变化影响不大,柠檬酸对其有显著影响,抗氧化剂对其有极显著影响。添加剂的最佳添加量为:0.03%植酸+0.03%EDTA,1.4‰柠檬酸,8%蔗糖;90℃灭菌15 min、灭菌后快速冷却有利于保存番茄汁中的维生素C;从保藏条件来看,利乐包较其它包装材料维生素C的保存率更高,储藏温度以冷室(15℃~18℃)条件为宜,储藏时间越短,番茄汁中维生素C的损失越少。     

鱼类饲料添加维生素应注意的四个问题

一、维生素添加量的确定　由于维生素的种类多,分析困难,饲料加工厂不可能将所有饲料原料一一加以分析,此外,在生产加工过程中维生素在环境条件、加工、贮存、运输等因素而造成损失。因此,通常将基础饲料中维生素的含量计为０,即不加计算,而以饲养标准或营养标准规定的需要量作为添加量,并考虑到其他因素造成的损失,增加１０％的安全系数进行计算。在计算添加量时还要考虑到维生素价格和经济承受能力。二、维生素的配伍禁忌　添加维生素时要注意它们之间的相互作用,对一些易被破坏的维生素应选用包膜制剂。胆碱有很强的碱性,因此…     

椪柑酒的树脂脱苦工艺优化研究

目的研究树脂对椪柑酒的脱苦效果。方法以椪柑酒为研究对象,采用单因素试验和正交优化试验研究X16树脂添加量、作用温度、作用时间以及转速对椪柑酒中柠檬苦素、诺米林及维生素C含量的影响。结果 X16树脂对苦味物质的脱除有显著影响。椪柑酒脱苦优化后的最佳工艺条件为:添加4%树脂,作用温度25℃,作用时间25 min,转速100 r/min,柠檬苦素和诺米林脱除率分别为49.54%、33.69%,维生素C的损失率为25.12%。结论树脂对椪柑酒的脱苦效果明显,营养成分存在一定损失,在实际生产应用中,可加入适量糖来降低其损失或添加维生素C补充剂增强营养功能。     

强化乳制品中维生素A稳定性的研究

通过研究不同储藏温度、光照条件以及货架期对强化乳制品维生素A的稳定性变化规律,为强化乳制品的保藏及合理饮用时间提供参考。采用紫外分光光度法直接测量强化乳制品中维生素A的含量,试验结果表明,储藏温度、光照条件和时间对强化乳制品中维生素A的稳定性影响显著。在低温条件下避光保存,保质期内饮用,强化乳制中的维生素A利用效率高。     

基于PI荧光图像计数的乳制品荧光性质分析

为分析添加PI染料时乳制品中不同的荧光成分如酪蛋白、黄油、维生素B1、维生素B2、维生素C等对荧光图像观察的影响,探究了不同乳制品及其成分在PI染色观察条件下的荧光性质,并以酿酒酵母为目标菌,研究了10种乳制品中酿酒酵母PI荧光图像计数结果。结果表明,酪蛋白、黄油、维生素B1、维生素B2、维生素C等成分及10种乳制品在发射光615 nm均可产生荧光,但不影响PI染色的酿酒酵母荧光计数的观察结果。使用荧光显微镜对添加105~107 CFU/mL酿酒酵母菌液的10种乳制品进行PI染色计数,并将荧光图像计数结果与平板计数结果进行比较。其中经荧光图像计数后得到的菌液浓度对数值分别在5.69~5.93、6.18~6.28、7.13~7.21之间,对应平板计数结果的对数值分别5.49~5.63、6.02~6.06、7.02~7.06之间,二者结果一致。使用 PI 进行荧光图像计数时,乳制品荧光虽然存在但不会对酿酒酵母荧光图像观察与计数造成影响。     

蓝靛果微波泡沫干燥过程中维生素C降解过程模拟

受干燥条件影响,食品原料中营养成分常发生降解,为阐明微波泡沫干燥条件对蓝靛果中维生素C稳定性的作用规律,本研究在对各影响因素进行通径分析的基础上,分阶段建立维生素C降解动力学模型,并据此建立多物理场仿真模型.结果表明:干燥过程中物料温度和含水率对维生素C降解同时存在直接影响和间接影响,温度升高和含水率下降均会导致维生素...     

乳制品中维生素A稳定性的研究进展

对加工工艺、储藏条件、光、氧气和脂肪质量分数等因素对液态奶或奶粉中维生素A稳定性影响的研究进展及其降解动力学进行了综述,并对如何提高其在产品中的稳定性进行了讨论.     

橙汁饮料中维生素C的无氧分解动力学

以橙汁饮料为实验材料,采用调节温度、光照强度促使维生素C无氧降解的方法,探讨橙汁饮料中维生素C的无氧降解动力学,为预测包装中维生素C的损失提供理论依据.研究结果表明,温度对饮料中维生素C的无氧降解反应速率符合一级反应模型,而光照强度对其的反应速率符合零级反应模型,从而得到了一定温度下,光照对饮料中维生素C影响的动力学模型.     

扁实柠檬汁中维生素C对抑制梨汁褐变的初步研究

研究扁实柠檬汁中维生素C受温度影响降解的过程和对库尔勒香梨梨汁褐变的抑制作用。通过研究扁实柠檬汁贮藏过程中还原型维生素C和氧化型维生素C的降解与贮藏温度、贮藏时间的关系,建立降解动力学模型,通过正交试验了解扁实柠檬汁抑制梨汁褐变的最佳作用组合。研究证实扁实柠檬汁中维生素C对热不稳定,符合一级反应动力学,2%扁实柠檬汁添加量,在榨汁前添加,保持4℃的处理温度,0.2%Na Cl添加量是抑制梨汁褐变的最佳组合。研究结果可用于扁实柠檬汁贮藏温度的选择和贮藏期预测,也证实扁实柠檬汁是一种天然健康优良的果蔬褐变抑制剂。     

降低腌制金花菜亚硝酸盐含量的研究

研究了金花菜腌制过程中食盐、维生素C、柠檬酸、茶粉的添加量及腌制温度对腌制金花菜中亚硝酸盐含量的影响。研究结果表明,食盐添加量和腌制温度对亚硝酸盐含量的影响较大,选择相对较低的食盐添加量可以有效控制亚硝酸盐的生成,温度拟控制在25℃左右,维生素C、柠檬酸及茶粉的添加对腌制过程中亚硝酸盐的降低也有明显的效果,维生素C和茶粉添加量分别为0.15%～0.2%、2%～3%,柠檬酸作为辅助剂,在腌制过程中与维生素C共同作用有助于将亚硝酸盐控制在相对较低的水平。     

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.