乳酸菌产生的拮抗物质:一类延长食品货架期的生物防腐剂

对乳酸菌产生的非蛋白类拮抗物质和蛋白类拮抗物质及其作用机制进行了论述。其中非蛋白类拮抗物质主要包括有机酸、双乙酰(丁二桐)、过氧化氢、罗伊氏素(returein)，蛋白类拮抗物质主要是细菌素，包括羊毛硫细菌素(Lantibiotis)、小分子热稳定肽(SHSP)、以及大分子热不稳定肽(LHLP)。     

Quality,functionality, and shelf life of fermented meat and meat products: A review

Fermentation of meat is a traditional preservation method used widely for improving quality and shelf life of fermented meat products. Fermentation of meat causes a number of physical, biochemical, and microbial changes, which eventually impart functional properties, sensory characteristics, and nutritional aspects to these products and inhibit the growth of various pathogenic and spoilage microorganisms. These changes include acidification (carbohydrate catabolism), solubilization and gelation of myofibrillar and sarcoplasmic proteins of muscle, degradation of proteins and lipids, reduction of nitrate into nitrite, formation of nitrosomyoglobin, and dehydration. Dry-fermented sausages are increasingly being used as carrier of probiotics. The production of biogenic amines during fermentation can be controlled by selecting proper starter cultures and other preventive measures such as quality of raw materials, hygienic measures, temperature, etc.     

Behaviour of volatile compounds during the shelf life of yoghurt

The production of acetaldehyde, diacetyl and ethanol was evaluated in whole plain yoghurts manufactured with commercial starter cultures, yoghurt acquired in a local market, and milk fermented by a single culture of either Streptococcus thermophilus or Lactobacillus delbrueckii ssp. bulgaricus . The headspace technique was used for sample preparation, following identification and quantification by gas chromatography. During an 8-h incubation period, mixed cultures were the most efficient in lowering the pH (from 6.30 to 4.8), followed by S. thermophilus (from 6.30 to 5.18) and L. bulgaricus (from 6.30 to 5.8). During the storage period, however, a single culture of L. bulgaricus decreased the pH more than S. thermophilus , but still less than the mixed commercial cultures. Plain yoghurts acquired in the market, those made with commercial starter cultures, and fermented milks obtained with single cultures showed, after 21 days of storage, concentrations of acetaldehyde from 11 to 35 mg/L, and of diacetyl from 0 to 0.85 mg/L. An increasing concentration of ethanol was observed during the storage period, and its production was observed even in the incubation stage of all products. It was also observed that the acetaldehyde concentration was inversely correlated to ethanol production in some products. The combination of headspace, identification and quantification techniques by gas chromatography in this work was efficient in the identification and quantification of the major aromatic compounds and ethanol content of yoghurt.     

块菌天然复配保鲜剂的配方优化及货架期预测

以橄榄叶提取物和壳聚糖制作复配保鲜剂,探究其对印度块菌(又名松露)的保鲜效果。以块菌的失重率、总糖含量、Vc含量、呼吸强度为测定指标,筛选最佳浓度的壳聚糖和橄榄叶提取物,并利用滤纸片法考察橄榄叶提取物的抑菌能力。在此基础上,开展复配试验以确定最佳保鲜剂配方和预测货架期。复合保鲜剂的最佳配方为:橄榄叶粗提物20 g/L、壳聚糖15 g/L。与未做保鲜剂处理的块菌相比,该配方能较好地降低块菌的失重率,维持总糖和Vc含量,对呼吸强度具有一定抑制作用。对块菌进行货架期预测显示,其中以质量保留率下降3%为终点的货架期预计可达44 d,以Vc含量下降50%为终点的货架期为21 d。     

食品感官货架期确定的一般原则与方法

感官品质是描述和判断食品质量最直观的指标,将此品质作为货架寿命的评价指标而确定的货架期为感官货架期,则对应的感官评价方法是确定感官货架寿命的关键技术之一。由此,结合感官评价方法与货架期预测原理,提出了食品感官货架期确定的一般原则与方法,旨在指导构建我国不同类型食品感官品质的货架期确定指南,完善食品货架期检测标准,为我国食品质量与控制的保障提供标准化支撑。     

Stability of nutritionally important compounds and shelf life prediction of tomato ketchup

Ketchup is an important source of tomato antioxidants in human nutrition, this ambient stable product is processed using several relatively important heat treatments and can be stored for one or more years at ambient temperature. Model storage experiments were carried out with two sets of commercial ketchup produced according to the Czech recipe: (a) hot-filled without subsequent pasteurization and (b) filled and pasteurized in the jar. The samples were stored at 25, 50, 75 and 90 °C, during the storage the content of total lycopene and ascorbic acid was observed as well as the colour parameters (a*, ΔE). The obtained data were processed using the pseudo first order (total lycopene, ascorbic acid and a*) and zero order kinetics (ΔE). The obtained results corresponded with the published data, but were not consistent between the both sets of the samples. The total lycopene and ascorbic acid degradation is more dependent on the conditions in the product, mainly on the previous history of heat treatment. The colour parameters, especially ΔE seemed to be more robust criterion, which could be used for the shelf life prediction estimation. The empirically set up shelf life by the producer was confirmed.     

Internal corrosion and shelf‐life of food cans and methods of evaluation

Internal corrosion in food cans is characterized by metallic dissolution which is an electrochemical reaction. In lacquered cans, corrosion may also cause disruption in the continuity of the lacquer film. These reactions may cause organoleptic changes in the product, loss of vacuum, swelling, and leaking in extreme cases. In some instances the metal dissolution (i.e., lead) may give rise to toxicological problems. Therefore, these phenomena are often the limiting factor in the shelf life of canned products. Changes in color, texture, and sensoric properties of the foods, which take place simultaneously, affect the aesthetic and nutritional value of the product and thus its shelf life. These changes are often related to interactions with the container. For example, tin dissolution prevents browning and loss of ascorbic acid. Shelf life of canned foods is governed by the quality of the raw materials, the processing technology, quality of the container and storage conditions which will be reviewed in this paper. Can manufacturing technologies, mechanisms of electrochemical corrosion, methods of their measurement and prediction of shelf life will be discussed.     

Microgreen nutrition,food safety,and shelf life: A review

Microgreens have gained increasing popularity as food ingredients in recent years because of their high nutritional value and diverse sensorial characteristics. Microgreens are edible seedlings including vegetables and herbs, which have been used, primarily in the restaurant industry, to embellish cuisine since 1996. The rapidly growing microgreen industry faces many challenges. Microgreens share many characteristics with sprouts, and while they have not been associated with any foodborne illness outbreaks, they have recently been the subject of seven recalls. Thus, the potential to carry foodborne pathogens is there, and steps can and should be taken during production to reduce the likelihood of such incidents. One major limitation to the growth of the microgreen industry is the rapid quality deterioration that occurs soon after harvest, which keeps prices high and restricts commerce to local sales. Once harvested, microgreens easily dehydrate, wilt, decay and rapidly lose certain nutrients. Research has explored preharvest and postharvest interventions, such as calcium treatments, modified atmopsphere packaging, temperature control, and light, to maintain quality, augment nutritional value, and extend shelf life. However, more work is needed to optimize both production and storage conditions to improve the safety, quality, and shelf life of microgreens, thereby expanding potential markets.     

滇牡丹籽油的脂肪酸组成及不同天然抗氧化剂对其货架期的影响

采用气相色谱法测定了滇牡丹籽油中的主要脂肪酸组成及含量,通过Rancimat法测定了滇牡丹籽油的氧化稳定性,并分析比较了不同天然抗氧化剂对滇牡丹籽油的抗氧化效果,进而推测出滇牡丹籽油在常温20℃下的货架期。结果表明:滇牡丹籽油的主要脂肪酸组成为油酸0.46%、亚油酸15.48%、亚麻酸74.09%、棕榈酸6.62%、硬脂酸1.37%,其中不饱和脂肪酸含量高达90.03%;天然抗氧化剂的抗氧化效果为原花青素滇牡丹籽黄酮二氢杨梅素V_EV_C茶多酚β-胡萝卜素,添加0.04%原花青素时,常温20℃下滇牡丹籽油的货架期为179.83 d。     

后杀菌与食品添加剂对酸奶保质期的影响研究

通过对发酵型酸奶分别进行后杀菌和添加适量食品添加剂,观察处理后酸奶的组织状态、口感风味和保质期等各种指标的变化,结果为:60℃20min后杀菌和添加适量食品添加剂效果最佳,所制酸奶组织状态好,风味佳,保质期达14d。     

Recent advances in shelf life prediction models for monitoring food quality

Each year, 1.3 billion tons of food is lost due to spoilage or loss in the supply chain, accounting for approximately one third of global food production. This requires a manufacturer to provide accurate information on the shelf life of the food in each stage. Various models for monitoring food quality have been developed and applied to predict food shelf life. This review classified shelf life models and detailed the application background and characteristics of commonly used models to better understand the different uses and aspects of the commonly used models. In particular, the structural framework, application mechanisms, and numerical relationships of commonly used models were elaborated. In addition, the study focused on the application of commonly used models in the food field. Besides predicting the freshness index and remaining shelf life of food, the study addressed aspects such as food classification (maturity and damage) and content prediction. Finally, further promotion of shelf life models in the food field, use of multivariate analysis methods, and development of new models were foreseen. More reliable transportation, processing, and packaging methods could be screened out based on real-time food quality monitoring.     

Use of active compounds for prolonging the shelf life of mozzarella cheese

The effectiveness of lysozyme and ethylenediaminetetraacetic disodium salt (Na₂-EDTA) against the spoilage microorganisms of mozzarella cheese was studied. Mozzarella cheeses were packaged in a conditioning solution (diluted brine), which contained lysozyme (0.25 mg mL⁻¹) and different amounts of Na₂-EDTA (10, 20 and 50 mmol L⁻¹), and stored at 4 °C for 8 days. The population of spoilage microorganisms (total coliforms and Pseudomonadaceae), along with the functional microbiota of mozzarella cheese (lactic acid bacteria) was enumerated. Lysozyme and Na₂-EDTA significantly inhibited the growth of coliforms and Pseudomonadaceae during the first 7 days of storage, whereas the functional microbiota (or lactic acid bacteria) were not affected. The results of this study showed that it is possible to extend the shelf life of mozzarella cheese through the use of lysozyme and Na₂-EDTA in the conditioning brine.     

一起抽检不合格保质期较短现制现售食品案例引发的思考

本文以一起市级食品安全监督抽检不合格的现制现售保质期较短食品牛奶小蛋仔案为例,分析了因餐饮食品（现制现售食品）保质期较短,抽检检验报告签发日期在其食品保质期之后,被抽检单位对收到的检验结果有异议提出复检,当地市场监督管理部门根据《食品安全抽样检验管理办法》规定“复检备份样品超过保质期的不予复检”而引起的争议。并就如何进一步完善食品安全监督抽检的法律法规,强化检验检测机构的风险管控和切实履行企业第一责任人的主体责任等三个方面提出了解决路径,以供借鉴。     

不同温度对货架期樱桃挥发性物质变化的影响

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大豆分离蛋白与大豆磷脂比例对超声乳化亚麻籽油乳液特性的影响

为探究复合乳化剂对不同油脂乳化效果的影响,以大豆分离蛋白（SPI）和蔗糖酯（SE）为复合乳化剂,猪油（LA）、大豆油（SO）、亚麻籽油（LO）、鱼油（FO）为油相制备乳液。通过测定乳液的乳化活性、结构特性、热特性、稳定性等指标,研究了不同油相制备的乳液之间稳定性的差异。结果表明,四种乳液中乳液_LA有最高的乳化活性和乳液稳定性（27.374 m²/g,361.243 min）,且其乳液液滴平均粒径（D）最小（8.411±0.670 μm）。微观结构结果显示,四种乳液颗粒的均匀性为乳液_LA >乳液_SO >乳液_LO >乳液_FO。DSC结果表明,乳液_LA熔融时需要最多的能量（ΔH=−57.67±1.28 J/g）,而乳液_FO的焓值仅为−10.18±0.10 J/g。储藏及氧化稳定性的结果表明,乳液_LA的稳定性最佳。油脂中不饱和脂肪酸的差异会影响SPI-SE对乳液的稳定效果,油相的不饱和脂肪酸比例越大、不饱和程度越高,乳液稳定性越差。该结果可丰富SPI-SE在油脂乳化上的研究,为油脂的乳化应用提供一定的参考依据。

     

食品等产品有效期预测及应用的研究进展

食品、药品及化妆品的有效期不仅仅是相关产品品质质量的保证,还是消费者购买商品时最注重的质量要求,也进一步从侧面反映出对产品质量安全的保证。随着消费者们对产品质量的要求越来越高,食品等产品的有效期研究也越来越引起人们的重视。通过对目前市场上常用的多种有效期预测模型(Arrhenius方程法、初均速法、Q_(10)法、Weibull危害分析模型、基于Global Stability Index(GSI)理论的多因素预测模型)及其在食品、药品和化妆品相应领域的应用的总结回顾,本文主要对产品有效期的定义、预测模型及其应用进行了综述,并对未来产品有效期预测的研究进行了展望。     

Retention of aroma compounds in food matrices of similar rheological behaviour and different compositions

Two matrices with a similar rheological behaviour but with a different composition have been developed: one containing carbohydrates (d-glucose, pectin and starch) and in the second one, called complex matrix, a lipid (triolein) was added. The release of six aroma compounds is quantified by using the measurements of partition coefficients at thermodynamic equilibrium. The role of lipid (triolein) on the retention of all the aroma compounds was pointed out. The effect of carbohydrates was more complex: in comparison with water, ethyl hexanoate and trans-2-hexenal were more retained whereas diacetyl, 2-pentanone and cis-3-hexenol were “repulsed” from the matrix. The kinetic study of the release from these matrices had shown a decrease of the initial rate of release by reference with water. From carbohydrates matrix, the decrease of the release for three compounds (ethyl acetate, ethyl hexanoate, 2-pentanone) seemed to arise from the variation of diffusion and/or retention by carbohydrates. For the three other aroma compounds (diacetyl, cis-3-hexenol and trans-2-hexenal) no variation of the initial rate was registered. The comparison of the release rates from carbohydrate and complex matrices indicated the role of lipids and the comparison of the release rates from water and complex matrix showed the combined effects of texture and lipids. The decrease of initial release rate was more important in presence of lipids than in presence of carbohydrates. The most important decrease was observed with the most hydrophobic compound.     

Estimate of the prevalence and burden of food poisoning by natural toxic compounds in South Korea

Many studies have attempted to accurately estimate the overall number of cases of foodborne illness, but there have not been many attempts to estimate the burden of foodborne disease caused by natural toxic compounds. This study estimated the number of cases due to specific natural toxins (seafood toxins, plant toxins, and mycotoxins) during 2008–2012 in South Korea, using data from the Health Insurance Review and Assessment Service (HIRA), while accounting for uncertainty in the estimate. The estimated annual occurrences of foodborne illness from natural toxic agents were 1088 (90% credible interval [CrI]: 883–1315), which suggests there are 21 times more cases than are reported, with 45.6% (n = 496 [388–614]) and 54.4% (n = 592 [423–790]), accounting for inpatient stays and outpatient visits, respectively. Among toxins, mushroom and plant toxins caused the highest illnesses, followed by toxic agents in seafood and mycotoxins. The 55–59 year olds had the highest proportion of illnesses and those over the age of 40 accounted for 70.6% of all cases. The cases caused by mushroom poison, poisonous plants, and seafood toxins showed clear seasonal and regional differences. These results will be useful to food safety policymakers for the prevention and control of natural food poisons in South Korea.     

Simulating shelf life determination by two simultaneous criteria

The shelf life of food and pharmaceutical products is frequently determined by a marker's concentration or quality index falling below or surpassing an assigned threshold level. Naturally, different chosen markers would indicate different shelf life for the same storage temperature history. We demonstrate that if there are two markers, such as two labile vitamins, the order in which their concentrations cross their respective thresholds may depend not only on their degradation kinetic parameters but also on the particular storage temperature profile, be it isothermal or non-isothermal. Thus, at least theoretically, the order observed in accelerated storage need not be always indicative of the actual order at colder temperatures, except where the two degradation reactions follow the same kinetic order and their temperature-dependence rate parameter is also the same. This is shown with simulated hypothetical degradation reactions that follow first or zero order kinetics and whose rate constant's temperature-dependence obeys the exponential model. It is also demonstrated with simulated hypothetical Maillard reaction's products whose synthesis rather than their degradation follows pseudo zero order kinetics. The software developed to do the simulations and calculate the thresholds crossing points has been posted on the Internet as a freely downloadable interactive Wolfram Demonstration, which can be used as a tool in storage studies and shelf life prediction. In principle, the methodology can be extended from two to any number of markers.