酱油中氯丙醇测定的注意事项

探讨了气质联用测定氯丙醇时应该注意的前处理问题,即盐析、吸附、预洗脱、洗脱、脱水、浓缩、衍生的样品前处理方法,避免人为误差,确保灵敏度和回收率,为从事食品检验工作者提供一定的参考.     

婴幼儿配方乳粉中氯丙醇酯含量测定方法的研究

建立气相色谱-质谱法（GC-MS）同时测定婴幼儿配方乳粉中3-氯-1,2-丙二醇酯（3-MCPDE）和2-氯-1,3-丙二醇酯（2-MCPDE）的分析方法。样品中加入氘代同位素内标,经乙酸乙酯提取、甲醇钠-甲醇溶液水解、七氟丁酰基咪唑衍生,气相色谱-质谱法选择离子监测（SIM）模式分析,内标法定量。结果表明,两种化合物在10～400 μg/L范围内线性关系良好,相关系数R2＞0.999,方法检出限均为0.003 mg/kg,定量限均为0.01 mg/kg;在3个加标浓度水平下的平均回收率为95.8%～115.7%,精密度试验结果的相对标准偏差（RSD）为1.9%～2.2%。该方法简便、快速、准确、灵敏度高,能够满足婴幼儿配方乳粉中氯丙醇酯快速检测的要求。     

GC-MS测定富含油脂类食品中氯丙醇的方法研究

建立了油脂类食品中氯丙醇含量的气相色谱-质谱法（GC-MS）联用技术检测方法,对油辣椒、腐乳、火锅底料以及鸡辣椒等食品中氯丙醇含量进行检测。结果表明：在10～500 μg/L范围内,3-氯-1,2-丙二醇（3-MCPD）的质量浓度与峰面积呈良好的线性关系,相关系数R2为0.999 5,方法检出限（LOD）为4.7 μg/kg,定量限（LOQ）为10.2 μg/kg,平均加标回收率在86.2%～108.5%,精密度试验测定得相对标准偏差（RSD,n=6）为4.26%。表明该方法准确、可靠、稳定,能够满足油脂类食品中氯丙醇含量的检测要求。     

食品中氯丙醇脂肪酸酯风险及应对措施概述

氯丙醇酯作为食品中的一类新型污染物,得到世界各国和地区的广泛关注和研究。氯丙醇酯类物质种类繁多,其反应机制、毒理学和代谢转化研究尚不成系统,目前研究表明氯丙醇酯类物质具有一定的肾脏、生殖毒性及潜在的致癌性。国内外对氯丙醇酯的检测方法、污染水平和暴露评估等研究主要集中在3-氯-1,2-丙二醇酯和2-氯-1,3-丙二醇酯,且主要集中在婴儿配方奶粉、油炸和烘焙食品等脂肪含量较高的食品上。通过研究发现,普通消费者从日常饮食中摄入氯丙醇酯类物质一般是无风险的,但对于一些年轻群体和仅食用配方奶粉的婴幼儿来说风险较高。国内外已相继开展了对氯丙醇酯的研究和监控,以减少食品中氯丙醇酯类物质污染水平。目前只有欧盟制定了3-氯-1,2-丙二醇酯在部分食用油和婴幼儿配方食品中的限量要求,仅国际食品法典委员会制定了植物油中3-氯-1,2-丙二醇酯的控制规范,来降低氯丙醇酯的风险。鉴于此,本文主要对氯丙醇酯形成机制、代谢、毒性、国内外食品中氯丙醇酯的污染水平、风险评估研究进展及其管理控制措施等方面进行了简要概述,以期为食品安全监管提供参考。     

油脂中氯丙醇形成机制及控制研究进展

食品中的氯丙醇污染是目前国际上广为关注的食品安全问题之一, 最初在酸水解植物蛋白加工中被检出, 近年来发现氯丙醇及其酯类化合物广泛存在于油脂及其加工品中, 成为危害消费者身体健康的又一隐性因素, 从而引起人们的再次高度关注。本文较为全面地介绍了氯丙醇的定义、分类, 分析了氯丙醇的潜在毒性及在食品中的污染现状, 总结了氯丙醇特别是3-氯-l,2-丙二醇(3-monochloropropanol-l,2-diol, 3-MCPD)的可能形成途径, 并归纳了油脂加工过程中可行的控制方法。     

婴配食品中氯丙醇酯的污染状况及检测方法研究进展

氯丙醇酯类污染物对人体具有潜在的危害,目前已被发现普遍存在于精炼植物油、含油脂性食品及动物乳汁及母乳中,其中精炼植物油尤其是精炼棕榈油中的污染水平较高。婴配食品中脂肪的主要来源是精炼植物油及动物脂肪,对于以婴配食品为主要食物来源的婴儿来说,此类污染物的暴露水平较高可能造成潜在的健康危害。目前婴配食品中氯丙醇酯类污染物的研究数据有限,且国内外相关法律法规不足,造成监管及生产环节关注有限。本文以婴配食品为关注点,综合介绍了国内外婴配食品中的氯丙醇酯污染状况及暴露危害、相关法律法规,并简要介绍了婴配食品中常用的氯丙醇酯检测方法,以帮助监管机构、生产企业及检测机构全面了解行业氯丙醇酯污染现状并及时做出改善。     

几种市售婴幼儿配方奶粉中氯丙醇酯的定量检测及风险评估

目的对几种市售婴幼儿配方奶粉中2种氯丙醇酯进行定量检测并开展人体健康风险暴露评估。方法奶粉样品提取脂肪后,经碱水解,以硅藻土固相萃取法净化,样液经衍生后采用气相色谱/质谱联用法(gas chromatography/mass spectrometry, GC/MS)检测,以稳定性同位素内标法对3-氯-1,2-丙二醇酯和2-氯-1,3-丙二醇酯进行定量。结果奶粉中3-氯-1,2-丙二醇酯和2-氯-1,3-丙二醇酯的检出率分别为87.5%和62.5%,平均值分别为0.058 mg/kg和0.022 mg/kg。低月龄婴幼儿氯丙醇酯暴露风险较高,超出每日耐受摄入量(tolerable daily intake, TDI)[0.8μg/(kg·d)]。结论婴幼儿配方奶粉中氯丙醇酯污染问题应高度关注,尽快制定限量标准,以降低氯丙醇酯对婴幼儿造成的健康风险。     

Lipoxygenases: From Isolation to Application

The positive effect of lipoxygenase, added as an enzyme‐active soy flour, during the production of white bread is well established. In addition to increasing the mixing tolerance and overall dough rheology, lipoxygenase is also an effective bleaching agent. It is known that these effects are mediated by enzyme‐coupled cooxidation of gluten proteins and carotenoids. However, the mechanism whereby these effects are achieved is not yet fully understood. In order to gain a better understanding into the reactions governing the beneficial effects of lipoxygenases in bread dough, an in‐depth knowledge of the lipoxygenase catalytic mechanism is required. Until now no single review combining the molecular enzymology of lipoxygenase enzymes and their application in the baking industry has been presented. This review, therefore, focuses on the extraction and molecular characterization of lipoxygenases in addition to the work done on the application of lipoxygenases in the baking industry.     

冰淇淋:从“清凉”走向“健康”

<正> 我国冰淇淋市场容量的逐步扩大,吸引了巨大资本的追捧和关注,这一切都为中国冰淇淋工业的发展带来了广阔的市场前景,也为中国冰淇淋制造商注入了新的动力和希望。为迎合不同的消费者,冰淇淋制造商均在"新"上下苦功,整个行业也有了新的发展方向。消费趋向营养与功能随着冰淇淋行业的发展壮大,其产量也在以空前的速度增长,市场在急剧地     

镀钴及其合金添加剂

本介绍了钴及其合金镀液的具有代表性的添加剂和典型配方,提出了与工艺,添加剂有关的几个问题,后附16篇参考献。     

Milk-derived bioactive peptides: From science to applications

Milk proteins have received increasing attention as potential ingredients of health-promoting functional foods targeted at diet-related chronic diseases, such as cardiovascular disease, diabetes type two and obesity. To this end, growing interest has been focused on physiologically active peptides derived from milk proteins. These peptides are inactive within the sequence of the parent protein molecule and can be liberated by gastrointestinal digestion of milk, fermentation of milk with proteolytic starter cultures or hydrolysis by proteolytic enzymes. Milk protein-derived peptides have been shown under in vitro and in vivo conditions to exert a number of activities affecting the digestive, endocrine, cardiovascular, immune and nervous systems. A great variety of naturally formed bioactive peptides have been found in fermented dairy products, such as yoghurt, sour milk and cheese. Recently, industrial-scale technologies suitable for the industrial production of bioactive milk peptides have been developed. In addition, a few commercial food products supplemented with milk protein-derived bioactive peptides have been launched on limited markets. Some of these products carry clinically documented benefits, in particular for reduction of mild hypertension. The multifunctional properties of milk peptides appear to offer considerable potential for the development of many similar products in the near future.     

Nanotechnology in agro-food: From field to plate

Application of nanotechnology in the agro-food sector is one of the fastest growing fields in nano-research. The increase in number of the publications, patents and intellectual property rights in the field of nano-agri-food and recent research trends in food processing, packaging, nutraceutical delivery, quality control and functional food is by itself an evidence of the above statement. Government organizations, scientists, inventors as well as industries are coming up with new techniques, protocols and products that have a direct application of nanotechnology in agriculture and food products.This review provides a detailed overview of the application of nanotechnology in the field of agriculture, and food science & technology. Additionally, a brief idea about the classification of nanomaterials, synthesis and characterization techniques is discussed. Some exciting thoughts are also discussed on nanotechnological applications in agricultural practices including nano-agri for enhanced productivity, agricultural water quality management (WQM), product processing, storage and quality control with nano-sensors. The risk assessment and safety concerns with respect to nano agro-food research have also been highlighted.     

Lactoperoxidase: From catalytic mechanism to practical applications

The catalytic activity and mechanism of lactoperoxidase is still being explored. New insights include a possible role of the reaction intermediate compound-III in (pseudo)catalase activity, the formation of a radical at an amino acid residue and interaction with NO. Although sometimes questioned, the finding that lactoperoxidase is present in human airway epithelia where it is the major hydrogen peroxide consumer shows the physiological relevance of some of these new insights. New developments on the applications of lactoperoxidase include new targets, e.g. Helicobacter pylori and powdery mildew, as well as synergistic combinations of lactoperoxidase with other antimicrobial compounds. A very promising development is the identification of the defense response of microorganisms when exposed to lactoperoxidase and its reaction products.     

From egg to embryo: a peripatetic journey

The recent surge of interest in oocyte development has been spurred in large part by the increasing implementation of assisted reproductive technologies (ART) to treat human infertility. What is becoming apparent is that 'egg quality' is a primary factor in the success of ART (Sauer 1998), and yet we know virtually nothing about the molecular signature of a 'high quality' oocyte, i.e., an oocyte that is capable of maturing, being fertilized and supporting development to term. We are gaining marked insights, however, into how sperm activate eggs and the changes in gene expression that accompany preimplantation development. Nevertheless, embryo culture is known to effect gene expression (Rinaudo & Schultz 2004), the long-term consequences of which are only recently being unmasked. This review will briefly highlight these topics that were presented during the Biennial Joint Meeting of the UK Fertility Societies at Warwick University in April 2005.     

Supplementing additional cobalt as cobalt lactate in a high-forage total mixed ration fed to late-lactation dairy cows

Cobalt lactate is a highly soluble ruminal Co source. Prior research evaluating higher Co feeding rates demonstrated increased ruminal fiber digestion. Feeding high-forage (>70%) rations to late-lactation dairy cows to enhance income over feed cost could potentially benefit from higher ruminal-soluble Co inclusion rates to enhance ruminal fiber and nutrient digestibility. Twenty-four late-lactation [238 ± 68.8 d in milk (DIM) and 36.4 ± 5.4 kg/d milk] Holstein dairy cows (10 primiparous and 14 multiparous) were blocked by milk yield, DIM, and parity, and randomly assigned to 1 of 2 treatments. Treatments were (1) control, CoCO₃ total mixed ration (TMR) containing 12.5 mg/cow per day of cobalt (cobalt carbonate), and (2) cobalt lactate (Co-LAC), same CoCO₃ TMR but containing an additional 50 mg/cow per day of Co, via a 1% cobalt lactate product (CoMax, Ralco Inc.). The basal TMR was 70% forage [60% alfalfa baleage and 40% corn silage on a dry matter (DM) basis] and 30% of the respective experimental grain mix on a DM basis. Cows were fed the CoCO₃ TMR during the 7-d covariate period, followed by 4 wk of data collection when CoCO₃ and Co-LAC TMR were fed. Milk production (26.2 and 25.8 kg/d for CoCO₃ and Co-LAC, respectively) and dry matter intake (DMI; 22.9 and 23.1 kg/d) were similar for cows fed both Co treatments. Production of milk fat (1.02 and 1.09 kg/d), milk protein (0.87 and 0.91 kg/d), and lactose (1.17 and 1.26 kg/d) were similar for cows fed both treatments. Body weights (684 and 674 kg) were similar for cows fed both treatments. Rumen ammonia concentrations (15.8 and 12.3 mg/dL) were lower for cows fed Co-LAC compared with cows fed CoCO₃ (15.8 mg/dL). Ruminal molar acetate concentrations (59.5 and 61.1%) were greater for cows fed Co-LAC compared with cows fed CoCO₃. Feeding additional Co as cobalt lactate in the TMR did not enhance lactational performance (milk production, composition, DMI, or body weight changes) when fed a high-forage TMR but altered ruminal fermentation with decreased ruminal ammonia and increased ruminal acetate concentrations.     

The availability to pasture plants of native and applied soil cobalt in relation to extractable soil cobalt and other soil properties

In pot trials using a range of soils from South-East Scotland, plant cobalt concentrations were significantly correlated with the amounts of cobalt extracted from soil with 0.05 M calcium chloride. Plant cobalt concentrations were also correlated with soil pH, showing a decrease with increasing soil pH. There were no significant correlations between plant cobalt concentrations and 0.5 M acetic acid-extractable cobalt, 0.04 M EDTA-exttactable cobalt, isotopically exchangeable cobalt or total soil cobalt. Uptake of cobalt by ryegrass from cobalt added to the soil was inversely related to both the ability of the soil to sorb cobalt and to soil pH.     

承德市食用植物油中氯丙醇酯和缩水甘油酯污染水平与暴露风险评估

目的对承德市售食用植物油中氯丙醇酯和缩水甘油酯进行污染水平分析。方法样品加入适量内标液后,经碱水解脂肪,固相萃取柱脱水净化后,用七氟丁酰基咪唑进行衍生化处理,供气相色谱-质谱仪进样分析。结果在检测的市售的30份植物油样品中,3-氯丙醇酯、2-氯丙醇酯和缩水甘油酯的检出率为100%、93%(28/30)及83%(25/30)。3-氯丙醇酯及2-氯丙醇酯含量范围分别在0.15～1.06 mg/kg和0.03-0.66 mg/kg,缩水甘油酯含量范围在0.03～1.85 mg/kg。结论氯丙醇酯和缩水甘油酯污染在承德市食用植物油中广泛存在,检出率在80%以上,这意味着虽然通过食用植物油摄入氯丙醇酯和缩水甘油酯的健康风险不高,但仍然不能忽视这种风险。检测部门应加大对这两种物质的检测力度,以保障人民的健康安全。     

Frying Process: From Conventional to Air Frying Technology

ABSTRACT

Studies have shown that products resulting from oils heated for long periods under high temperatures contain polar compounds such as polymers, dimers, free fatty acids, and acrylamide, which lead to metabolic changes, malabsorption of essential fat, and development of cancer. The air frying process is capable of reaching the characteristic color and similar flavor obtained by deep fat frying, and reduces the amount of oil content and polar compounds. However, it has not been extensively studied and should receive a greater focus on the detailed evaluation of components and properties of foods and the effects on the human health.