Risk assessment of dietary exposure to phytosterol oxidation products from baked food in China

Phytosterols are nutritional phytochemicals that may undergo oxidation and be transformed into phytosterol oxidation products (POPs), thus inducing pathological and toxic effects. This work investigated four main phytosterols and 28 POPs in 104 kinds of commercial baked food by using GC-MS. The dietary exposure and hazard index values (HI) associated with POPs from baked food consumption in China were estimated by using Monte Carlo simulation. Concentrations of the total phytosterols were between 3.39 and 209.80 μg/g. The total concentrations of POPs, including 5α,6α/5β,6β-epoxysterols, 7-ketosterol, 7α/7β-hydroxysterols, 6-hydroxysterols, and triols, ranged from 0.37 to 27.81 μg/g. The median dietary exposure of POP contents in baked food for four age groups in China were 10.91 (children), 6.20 (adolescents), 3.63 (adults), and 3.40 (seniors) mg/(kg×day). Risk assessment of median HI with respect to POPs indicated no risk (HI <1) for people in adolescents, adults, and seniors in the country area of China, while a risk (1 < HI < 10) would refer to the baked food consumption of people in urban area and children in country area of China. Sensitivity and uncertainty analysis showed that the most significant variables for each age group in China were POP concentration, body weight, and ingestion rate.     

食品中植物甾醇氧化物研究进展

植物甾醇作为一种降胆固醇的功能性成分已被广泛用于食品及其配料中,但是其化学结构与胆固醇类似,易受光、热、氧、金属离子等作用,转变成对人体具有潜在危害的植物甾醇氧化物(POPs)。虽然对这种潜在危害还存在争议,但POPs已经引起了人们的关注。本文综合现有国内外有关文献,对POPs的来源分布、形成机理、生理作用及抑制有害POPs生成等几个方面的研究进展进行了总结,并对其研究发展趋势进行了展望。     

动物性食品中胆固醇氧化产物的研究进展

动物性食品中的胆固醇氧化产物(Cholesterol Oxidation Products,COPs)的健康效应受到广泛关注。其水平在新鲜动物性食材中均很低,但在储藏加工和家庭烹调中可能有显著增加。文章介绍了水产品、畜产品、蛋制品及乳制品4类食品中影响胆固醇氧化产物形成的因素。研究表明长时间储藏、高温、非适宜的水分活度、与光线和氧气接触等因素均会促进胆固醇氧化产物的形成。烹调中加入油脂的饱和程度和所含抗氧化物质也影响动物性食物烹调后COPs的形成。加入适量的天然抗氧化物质可能有利于减少COPs的生成。     

Determination of phytosterol oxides in some food products by using an optimized transesterification method

An increased intake of phytosterols (PS), as well as new products launched on the market enriched with PS and phytostanols, increases the demands for improved analytical techniques. In the present study, a method for the determination of phytosterol oxidation products (POP) was evaluated and optimized. The method included transesterification, enrichment with amino SPE cartridges and quantification by GC. The methodology was evaluated with authentic samples of sito-, campe- and stigma-sterol oxidation products and the linearity and recovery for some POP were >0.95 and 80–120%, respectively. The lowest spiking level determined was 0.5 μg and lower levels could be quantified. In addition, the formation of POP during thermal oxidation of vegetable oils at 180 °C for 0–2 h was studied and increased levels were observed. A commercially available PS ester-enriched margarine was also included in the investigation and the level of POP was 12 μg/g of spread.     

乳化食品中油脂氧化分析及其货架期评价方法的研究进展

油脂氧化是导致乳化食品变质的主要原因。油脂中的不饱和脂肪酸发生氧化,不仅会降低乳化食品的营养价值,还会产生不良风味、有害成分,进而影响乳化食品货架期和食用安全。相对于纯油体系,以乳化形式存在的油脂在高油-水界面比下极易发生氧化,缩短乳化食品的货架期。为明确乳化食品中油脂氧化分析以及其货架期评价方法,在介绍乳化食品中油脂氧化的基本过程的基础上,综述了乳化食品中油脂氧化分析方法(过氧化值、共轭二烯值、硫代巴比妥酸值、茴香胺值、挥发性物质含量)以及货架期的评价方法,为乳化食品中油脂氧化程度分析及其货架期预测提供参考。     

Lipids and phytosterol oxidation products in commercial potato crisps commonly consumed in Sweden

The stability of frying oils and fried foods is mainly affected by the fatty acids present and by the types and levels of minor components such as phytosterols and tocopherols. This study assessed the current status of lipid composition and the occurrence of oxidised phytosterols as a parameter of lipid oxidation in potato crisps available in the Swedish market. Fatty acid composition and concentrations of tocopherols, sterols and phytosterol oxidation products (POPs) were determined in 16 commercial potato crisp samples of two types, distinguished by a high or low fat content. The fatty acid composition in most samples was dominated by saturated and monounsaturated fatty acids. The sum of α-tocopherol and γ-tocopherol content varied from undetectable levels to 10.2 mg/100 g potato crisps, with α-tocopherol dominating. Among the tocotrienols, α-tocotrienol and γ-tocotrienol were present in almost equal proportions, while δ-tocotrienol was present in all samples but in smaller amounts. Fatty acid composition, tocopherol and tocotrienol content, showed that all potato crisp samples were prepared in palm oil or a blend of palm oil and unspecified fats and oils. Total sterol content ranged from 10.2 to 93.1 mg/100 g sample, with β-sitosterol being the major sterol in all samples. The content of POPs ranged from 0.05 to 0.68 mg/100 g potato crisps. In general, there were no significant differences in content of POPs between high and low fat samples, and generally no correlations could be established between content of POPs and fatty acid, tocopherol, tocotrienol, and sterol content among the potato crisp samples.     

Inhibition of cholesterol oxidation in marinated foods as affected by antioxidants during heating

Chinese marinated foods rich in cholesterol, such as eggs and pork, can be susceptible to formation of carcinogenic cholesterol oxidation products (COPs) during prolonged heating. The objectives of this study were to compare the effects of various antioxidants on the inhibition of COPs in marinated eggs, pork and juice. The various COPs in marinated food samples were analyzed by a GC–MS technique. The incorporation of antioxidants, vitamin C, vitamin E, BHA and trolox were all effective in inhibiting COPs formation, with vitamin C being the most pronounced in marinated eggs, and BHA in marinated pork and juice. The inhibition effect increased with increasing levels of BHA and trolox. However, vitamin E was more effective at a low level (0.02%) than at a high level (0.1%), probably because of prooxidant activity of the latter. The same phenomenon also occurred for 0.1% vitamin C in marinated eggs, but a reversed trend was observed in marinated pork and juice. The residual amounts of each antioxidant in marinated eggs, pork and juice were also determined by HPLC.     

焙烤类谷物食品糖基化产物的定性、定量评价方法

糖基化产物与心血管疾病、糖尿病等多种慢性病的发生有关,因此对食品中糖基化产物含量的评价尤为重要。研究了不同酶解条件对结合态糖基化产物的释放,并且建立了以色度、吸光度、荧光强度等为考察指标综合评价不同反应途径的糖基化产物含量的体系。结果表明:分别采用E320μg/mL和640μg/mL酶解焙烤类谷类食物,40℃酶解36 h,结合态糖基化产物释放较为充分。谷物早餐中美拉德反应产物含量低于饼干和面包;荧光性晚期糖基化终产物含量大小依次为:饼干(1 890 AU/mg)面包(1 886 AU/mg)谷物早餐(1 678 AU/mg)。另外,早餐谷物中初期(A_(208))、中期糖基化产物(A_(360))显著高于饼干和面包(P0.05),而早餐谷物中期和末期糖基化反应产物(戊糖素、5-HMF和HMF)含量显著低于面包和饼干(P0.05)。     

Occurrence and infant exposure assessment of nitrates in baby foods marketed in the region of Lisbon,Portugal

Commercial baby food labelled as from organic or conventional origin, including vegetable-based baby foods, fruit purees and fruit juices (n?=?80), were analysed for nitrate content by an in-house validated HPLC method. Nitrate contents ranged from 5 to 230?mg?kg^?1 with a mean concentration of 102?mg?kg^?1 for vegetable-based baby foods, and a median of 5?mg?kg^?1 for both fruit purees and juices. One sample of vegetable-based baby food was higher than the legislated value (200?mg?kg^?1). There were no significant differences between average nitrate levels in analysed samples regarding both farming systems. The estimated nitrate intake through baby foods for a mean nitrate concentration of 47?mg?kg^?1 ranged between 0.5 (15% of ADI) and 1.3?mg?kg^?1?bw?day^?1 (35% of ADI). The ADI level was exceeded (107–146% of ADI) only for the 95th and 99th percentiles of nitrate concentration.     

植物甾醇氧化物的形成、摄入及健康相关效应

植物甾醇（phytosterol,PS）是一类重要的生物活性物质,具有降低胆固醇、预防心血管疾病、抗癌、抗炎等生理功能,但由于其自身结构不稳定,易被氧化形成植物甾醇氧化物（phytosterol oxidation products,POPs）,POPs包括酮基类、羟基类和环氧氧化物。随着越来越多的PS强化食品进入人们的日常生活,PS的氧化、POPs的机体摄入及可能存在的危害已引起了消费者的广泛关注。本文查阅国内外有关POPs的最新研究成果,从POPs的形成、种类与结构、膳食暴露情况、机体吸收及健康相关效应等方面进行系统分析论述,以期为PS的氧化控制,特别是POPs的膳食摄入和风险评估提供科学参考。     

Physicochemical and structural changes of myofibrillar proteins in muscle foods during thawing: Occurrence,consequences, evidence,and implications

Myofibrillar protein (MP) endows muscle foods with texture and important functional properties, such as water-holding capacity (WHC) and emulsifying and gel-forming abilities. However, thawing deteriorates the physicochemical and structural properties of MPs, significantly affecting the WHC, texture, flavor, and nutritional value of muscle foods. Thawing-induced physicochemical and structural changes in MPs need further investigation and consideration in the scientific development of muscle foods. In this study, we reviewed the literature for the thawing effects on the physicochemical and structural characters of MPs to identify potential associations between MPs and the quality of muscle-based foods. Physicochemical and structural changes of MPs in muscle foods occur because of physical changes during thawing and microenvironmental changes, including heat transfer and phase transformation, moisture activation and migration, microbial activation, and alterations in pH and ionic strength. These changes are not only essential inducements for changes in spatial conformation, surface hydrophobicity, solubility, Ca²⁺-ATPase activity, intermolecular interaction, gel properties, and emulsifying properties of MPs but also factors causing MP oxidation, characterized by thiols, carbonyl compounds, free amino groups, dityrosine content, cross-linking, and MP aggregates. Additionally, the WHC, texture, flavor, and nutritional value of muscle foods are closely related to MPs. This review encourages additional work to explore the potential of tempering techniques, as well as the synergistic effects of traditional and innovative thawing technologies, in reducing the oxidation and denaturation of MPs and maintaining the quality of muscle foods.     

Occurrence and dietary exposure assessment of multiple mycotoxins in corn-based food products from Shandong,China

This study was designed to investigate the occurrence and exposure assessment of multiple mycotoxins in corn-based food products from Shandong Province, China. Results demonstrated that the mean level of total mycotoxins in test samples was 197.2 µg/kg. The most frequently found mycotoxins were deoxynivalenol (96.7%) and fumonisin B₁ (94.4%), with mean contamination levels of 65.24 and 128.2, respectively. Among these corn-based food products, thin corn pancake had the highest mean contamination (886.7 µg/kg), followed by wotou (143.7 µg/kg), corn cake (135.4 µg/kg) and mantou (63.73 µg/kg). The average exposure values to total fumonisins and deoxynivalenol were 0.05 and 0.02 µg/kg bw/day, which were lower than the provisional maximum tolerable daily intake values of 2 and 1 µg/kg bw/day, respectively, as established by the Joint FAO/WHO Expert Committee on Food Additives. In the future strict control and systematic monitoring are needed to secure food safety and human health.     

Prevention of lipid oxidation in muscle foods by milk proteins and peptides: A review

Muscle foods (especially fresh meat, precooked, and restructured meat products) are highly prone to lipid oxidation, which ultimately leads to certain problems, viz. discoloration, off-flavor, drip losses, loss of essential fatty acids and vitamins, and generation of toxic products. These problems can be minimized with the help of various agents and or techniques such as use of natural/synthetic antioxidants, metal chelating agents, physical conditions, vacuum packaging, and encapsulation techniques. Among these, the role of synthetic antioxidants is quite debatable due to certain health risks to humans. Among the natural molecules, milk proteins and their bioactive peptides offer a promising potential for the meat industry. Various forms of milk proteins and peptides including caseinates, whey proteins, skim milk, and milk co-precipitates can be used to prevent lipid oxidation in meat products either in the form of added ingredients or as edible coatings. However, in addition to prevention of lipid oxidation, they also provide nutritional benefits and improve the technological processing and shelflife of meat and meat products. This review focuses on the utilization, mechanism of action, and efficacy of milk proteins and peptides to inhibit lipid oxidation in muscle food products.     

武汉市面制食品中铝污染现状及膳食暴露评估

目的 调查武汉市面制品中铝污染现状, 并评估武汉居民的铝暴露情况。方法 根据随机抽样法采集武汉市面制食品共307件, 根据国家标准方法检测其中铝的含量, 并结合2002年中国居民膳食消费量调查结果, 评估居民面制食品中铝的暴露量。结果 307件面制食品中铝含量均值为235.4 mg/kg, 总检出率为55.7%, 总超标率为44.6%, 5类样品中铝含量存在显著性差异; 武汉市面制食品中铝的平均膳食暴露量为 3.63 mg/(kg?bw), 面制食品铝暴露量的P90值为11.5 mg/(kg?bw), 均高于联合国粮农组织/世界卫生组织食品添加剂联合专家委员会(Joint FAO/WHO Expert Committee on Food Additives, JECFA)制定的铝每周耐受摄入量(provisional tolerated weekly intake, PTWI)。结论 武汉市面制食品中铝暴露量存在安全隐患, 相关部门需要加大对该类食物中含铝添加剂滥用行为的监管力度。     

“三品一标”检测机构档案管理体系的构建研究

随着我国的人民物质生活条件不断提高,农产品质量安全也受到了广泛的关注,目前我国的农产品质量安全有了长足的进步,但仍然存在着一定的风险。"三品一标"农产品是我国政府倡导的优质农产品品牌标志,主要包括了无公害农产品、绿色食品、有机食品和地理标志农产品。我国的"三品一标"检测机构较多,但是相关的档案管理体系较差,人员素质较弱,不利于我国"三品一标"农产品的快速发展。为了进一步的完善我国的"三品一标"检测机构档案管理体系,促进我国"三品一标"农产品质量安全的健康发展,本文分析了"三品一标"检测机构档案管理体系建设的现状、意义与方法,为其他"三品一标"检测机构档案管理体系建设提供了一定的理论依据和实践基础。     

From polyphenol to o-quinone: Occurrence,significance, and intervention strategies in foods and health implications

Polyphenol oxidation is a chemical process impairing food freshness and other desirable qualities, which has become a serious problem in fruit and vegetable processing industry. It is crucial to understand the mechanisms involved in these detrimental alterations. o-Quinones are primarily generated by polyphenols with di/tri-phenolic groups through enzymatic oxidation and/or auto-oxidation. They are highly reactive species, which not only readily suffer the attack by nucleophiles but also powerfully oxidize other molecules presenting lower redox potentials via electron transfer reactions. These reactions and subsequent complicated reactions are capable of initiating quality losses in foods, such as browning, aroma loss, and nutritional decline. To attenuate these adverse influences, a variety of technologies have emerged to restrain polyphenol oxidation via governing different factors, especially polyphenol oxidases and oxygen. Despite tremendous efforts devoted, to date, the loss of food quality caused by quinones has remained a great challenge in the food processing industry. Furthermore, o-quinones are responsible for the chemopreventive effects and/or toxicity of the parent catechols on human health, the mechanisms by which are quite complex. Herein, this review focuses on the generation and reactivity of o-quinones, attempting to clarify mechanisms involved in the quality deterioration of foods and health implications for humans. Potential innovative inhibitors and technologies are also presented to intervene in o-quinone formation and subsequent reactions. In future, the feasibility of these inhibitory strategies should be evaluated, and further exploration on biological targets of o-quinones is of great necessity.     

Invited review: Potential effects of short- and long-term intake of fermented dairy products on prevention and control of type 2 diabetes mellitus

The consumption of fermented dairy products has been linked with lowering the risk of type 2 diabetes mellitus (T2DM), but studies have yet to demonstrate a definite association. We evaluated evidence from a cross-sectional analysis of longitudinal studies and human and animal experimental trials to further understand the current knowledge linking short- and long-term consumption of fermented dairy products to T2DM. Most cohort studies revealed a protective effect of fermented dairy products on T2DM development, with yogurt noted as the most consistent food item protecting against the disease. Human experimental trials and animal studies revealed improvements in biomarkers of glycemic control with short-term monitored intake of fermented dairy products from various sources. Therefore, fermented dairy products may offer protection against the development and may have therapeutic benefits for individuals with T2DM. This could influence on dietary recommendations and the development of functional foods aiming to minimize the risk of T2DM.     

Cholesterol oxidation products in irradiated raw meat with different packaging and storage time

The effect of irradiation and packaging conditions on the formation of cholesterol oxidation products (COPs) as well as lipid oxidation products was determined in raw turkey leg, beef, and pork loin meat during 7 days of storage. Ground turkey leg, beef, and pork loin muscles were prepared as patties. The patties were individually packaged either in oxygen-permeable or impermeable bags, irradiated at 0 or 4.5 kGy using a Linear Accelerator, and stored at 4°C. The COPs such as 7-hydroxycholesterol, 7β-hydroxycholesterol, and 7-ketocholesterol were detected in fresh raw meats at 0 day at the level of 10.9 to 49.2 μg/g lipid. After 7 days of storage, other COPs such as epoxides, 20-hyroxycholesterol, and choletanetriol were formed in mainly aerobically packaged and irradiated raw meats. Packaging effect was more crucial on the cholesterol and lipid oxidation than irradiation. In aerobically packaged and irradiated meats, turkey leg muscles had higher COPs value than beef or pork did. COPs and thiobarbituric acid reactive substances (TBARS) values had a strongly positive correlation in turkey leg and pork. But, cholesterol oxidation in beef proceeded in irradiated and aerobically stored samples despite of its low level of TBARS value.     

Biogenic amines in fish,fish products and shellfish: a review

Fish, cephalopods and shellfish provide a healthy source of high-quality proteins, essential vitamins, minerals and polyunsaturated fatty acids. The beneficial effects of fish consumption on human health such as protection against coronary heart disease and certain cancer may be offset by fish decomposition and the formation of chemical contaminants such as biogenic amines. There are several toxicological effects of biogenic amines on humans, especially histamine. It is the causative agent of histamine or scombroid fish poisoning which is a significant public health problem. In individuals with diminished histamine detoxification, ingestion of even a low or moderate histamine- or tyramine-containing fish may lead to food intolerance. Biogenic amines such as putrescine, tyramine and cadaverine can potentiate histamine toxicity. Furthermore, dietary polyamine intake should be minimised in some cancer patients. Besides their potential toxicity, biogenic amines are used for the evaluation of hygienic quality of different marine and freshwater species. Spoilage pattern and biogenic amine formation are species specific. Histamine has been traditionally used as an indicator of the quality of histidine-rich fish (dark-muscle fish). On the other hand, putrescine and cadaverine are the most objective indicators of quality of histidine-poor fish (white-muscle fish), shellfish and fermented seafood products.     

Occurrence and risk assessment of population exposed to deoxynivalenol in foods derived from wheat flour in Brazil

Deoxynivalenol (DON) is the most important of the trichothecenes in terms of amounts and occurrence in wheat. This compound was shown to be associated with a glomerulonephropathy involving an increase of immunoglobulin A in humans. This study assessed the occurrence of DON in wheat flour and the exposure of Brazilian teenagers, adults and elderly to this mycotoxin due to intake of wheat flour-based products. DON extraction in wheat flour was carried out by solid phase extraction and the quantification was performed by ultra-high proficiency liquid chromatography with diode-array detection. A total of 77.9% of all samples were positive for DON, with concentrations ranging from 73.50 to 2794.63 µg kg^?1. The intake was calculated for the average and 90th percentile of the contamination levels of DON in foods based-wheat for teenagers, adults and elderly in Brazil, and compared with the provisional maximum tolerable daily intakes (PMTDI). Females of all age groups were exposed to DON at higher levels when compared to males in regard of consumption of breads and pastas. Teenagers were the main consumers of foods derived from wheat flour, with maximum probable daily intakes of 1.28 and 1.20 µg kg^?1 b.w. day^?1 for females and males, respectively. This population is at an increased risk of exposure to DON due to consumption of wheat flour-based foods in Brazil.