毛细管电泳法对乳及乳制品中真蛋白的测定

利用毛细管电泳法对市售乳清蛋白粉、采自当地奶牛场的牛初乳及原料奶、同一品牌不同阶段或同一阶段内不同厂家、不同国别的婴儿配方奶粉、不同保质期的液态奶、不同国别的超高温灭菌(UHT)奶和酸奶、国产复原乳中α- 乳白蛋白(α-Lac)、β- 乳球蛋白A (β-LgA)及β- 乳球蛋白B (β-LgB)的质量分数进行测定。结果表明：α-Lac、β-LgA 及β-LgB 的质量分数在乳清蛋白粉、牛初乳及原料奶中依次降低。液态奶中上述3 种蛋白的质量分数与保质期有关,一般保质期越久的产品,上述3 种蛋白的质量分数越低。大多数酸奶中α-Lac 的质量分数均高于UHT 奶。婴儿配方奶粉中α-Lac 质量分数随着阶段数的增加而增加,而且同一阶段内不同厂家不同国别配方奶粉中α-Lac 质量分数差异也较大,并非进口奶粉中α-Lac 质量分数均比国产奶粉高。     

牛乳粉和小麦粉混合后营养价值变化的研究及婴儿食品的研制

本文研究了牛乳粉和小麦粉混合后蛋白质的营养价值变化。分别用牛乳蛋白质：小麦蛋白质１∶１和２∶１两种比例、单一小麦粉、单一牛乳粉、酪蛋白（参考蛋白质）配制饲料，喂养断乳大白鼠２８天，蛋白质功效比值分别为２．８１、２．７５、０．９３、２．６４、２．５０，同时测定各饲料的氨基酸组成。实验结果表明：牛乳粉和小麦粉混合后其限制性氨基酸得到了互补，提高了营养价值，ＰＥＲ值明显高于单一小麦粉或单一牛乳粉及酪蛋白。并制成婴儿断乳食品。     

Faster Measurement of Minerals in Milk Powders: Comparison of a High Power Wavelength Dispersive XRF System with ICP-AES and Potentiometry Reference Methods

A simple and quick (less than 5 min/pellet) method for the quantification of a series of macroelements (Na, Mg, P, Cl, K, and Ca) and trace elements (Fe, Cu and Zn) by wavelength dispersive X-ray fluorescence (WDXRF) has been established and validated for fortified milk powders, from a single production site. The calibration set of 23 samples was selected to uniformly cover the concentration ranges of each element. The validation set was composed of 32 samples. By using a high power WDXRF instrument, a counting time as short as 20 s for most of the analytes can be used to considerably decrease analysis time. Reference values obtained by inductively coupled plasma-atomic emission spectroscopy and by potentiometry for chloride were used to calibrate the WDXRF system. Subsequently, the WDXRF results were evaluated against those obtained from the reference methods. The results show good performance of the WDXRF method for routine analysis of milk powders including copper at low levels (<10 mg/kg). All the calibrations gave R ² > 0.98, while all validation work has been done using three replicates of each sample; the results have additionally been reassessed to check that only two replicates per sample would not lead to significant differences in terms of quality of data and could be considered for routine analysis to further decrease analysis time.     

Roles of Water and Solids Composition in the Control of Glass Transition and Stickiness of Milk Powders

Abstract: Plasticization and glass transition of amorphous components in food powders often result in stickiness and caking. The glass transition temperature (T_g) of milk powders was measured by differential scanning calorimetry (DSC) and a viscometer method was used to determine sticky-point temperatures. Water sorption isotherms were established for varying solids compositions. Lactose contents were analyzed by high-performance anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) and proteins were identified using SDS-PAGE gel electrophoresis. Solids composition and water affected both the T_g and stickiness behavior. Stickiness was governed by carbohydrates and water plasticization. At low protein contents, precrystallization of lactose decreased the sticky point temperature, but increasing protein content in all milk powders decreased stickiness at all water activities. The results showed that glass transition can be used to describe time-dependent stickiness and crystallization phenomena, and it can be used as a parameter to control and reduce stickiness of dairy solids with various compositions. Practical Application: Glass transition of component sugars in milk powders with various water contents was responsible for a solid-liquid transformation which resulted in their viscous flow at particle surfaces and stickiness of the powders. Stickiness leads to wall deposition in dehydration and caking of powders in storage when the amorphous carbohydrate-rich components gain liquid characteristics. High protein contents in milk powders decreased stickiness, but precrystallization of lactose prior to spray drying increased stickiness at low protein content. Milk powders in storage gained higher water contents with increasing protein contents, but stickiness was reduced and lactose crystallization was delayed which improved storage stability.     

乳酸菌抗氧化活性及其在发酵肉制品中的应用研究进展

乳酸菌作为发酵肉制品中的发酵剂,已被证实具有抗氧化活性,但在发酵过程中,容易受到各种环境胁迫因子的影响,这些胁迫因子能够诱发菌体胞内活性氧自由基的产生和积累,进一步影响菌株的抗氧化活性,很大程度上限制了其在发酵肉制品中的抗氧化作用。本文综述乳酸菌面临的环境胁迫因子,探究其对氧化胁迫的应答与防御机制和抗氧化机理,并阐述提升乳酸菌氧化胁迫抗性的策略及乳酸菌在发酵肉制品中的抗氧化作用。     

消费者对HACCP认证的支付意愿:基于北京市乳制品市场的调查

调查了北京地区消费者对HACCP认证的认知程度、支付意愿(WTP)以及相关问题,并采用算术平均法和计量方法分别估算了消费者对奶制品的HACCP认证的WTP。调查发现消费者对HACCP认证的认知和信任不足。另外,通过对信息强化前后的比较可知,经过信息强化后,使用算术平均法测算出消费者对HACCP认证的平均WTP为0.13元(占市场价格的8.46%),比信息强化前提高了0.04元。计量结果显示,消费者对该认证的平均WTP为0.11元(占市场价格的7.15%)。可见,加强HACCP认证的宣传能提高消费者对HACCP的认知和接受度。     

Energy Drinks: An Assessment of Their Market Size,Consumer Demographics,Ingredient Profile,Functionality, and Regulations in the United States

ABSTRACT: The consumption of energy drinks is rapidly increasing, as demonstrated by their large market growth. The targeted demographic group is teenagers, young adults, 18 to 34 y old; although expansion into nontraditional markets is also occurring. It is claimed that energy drinks can offer an increased energy boost related to their ingredient profile of caffeine, taurine, herbal extracts, and vitamins. Research suggests that energy drink formulations, in addition to increasing energy utilization, may also improve mood, enhance physical endurance, reduce mental fatigue, and increase reaction time. However, in most cases, the corresponding mechanisms of action are not clear. In addition, concerns have been raised over their safety and with a currently weak regulatory environment, efforts need to be made to ensure consumer safety. The objective of this article is to review the current U.S. energy drink market with emphasis on its market size, target demographic, active ingredients, potential benefits, safety, and regulations.     

发展我国畜产品加工业的意义和建议

本文简述了我国发展畜产品加工业的意义,并对我国畜产品加工业今后重点研究发展方向以及推进我国畜产品加工业发展的战略措施进行了探讨。     

Short Communication: Culture-Independent Detection of Lactic Acid Bacteria Bacteriocin Genes in Two Traditional Slovenian Raw Milk Cheeses and Their Microbial Consortia

Two Slovenian traditional raw milk cheeses, Tolminc (from cows’ milk) and Kraški (from ewes’ milk), were examined for the presence of 19 lactic acid bacteria bacteriocin genes by PCR analysis of total DNA extracts from 9 cheeses and from consortia of strains isolated from these cheeses. Eleven bacteriocin genes were detected in at least one cheese or consortium, or from both. Different cheeses or consortia contained 3 to 9 bacteriocin determinants. Plantaricin A gene determinants were found in all cheese and consortia DNA extracts. Genes for enterocins A, B, P, L50A, and L50B, and the bacteriocin cytolysin were commonly detected, as were genes for nisin. These results indicate that bacteriocinogenic strains of Lactobacillus, Enterococcus, and Lactococcus genera with protective potential are common members of indigenous microbiota of raw milk cheeses, which can be a good source of new protective strains.     

The Use and Effects of Lactic Acid Bacteria in Malting and Brewing with Their Relationships to Antifungal Activity,Mycotoxins and Gushing: A Review

Several metabolic properties of lactic acid bacteria (LAB) serve special functions, which directly or indirectly have impact on processes such as improved quality and safety and flavour development in the malting and brewing industry. LAB are widely distributed in nature and in spontaneous fermentations, often they are found to be the dominating microflora resulting in both the inhibition of spoilage bacteria and organisms. This review describes the applications of LAB in malting and brewing. Mycotoxins are naturally occurring toxic secondary metabolites of fungi that may be present in cereals. Several of these mycotoxins have been associated with human and animal diseases and are known to survive the brewing process. LAB have been shown to restrict the growth of the most important toxigenic fungi thereby reducing the formation of these harmful toxins. The occurrence of mycotoxins in cereals is discussed and their effect in beer is reviewed. The main features of this review are: (I) LAB starter cultures in malting and brewing (II) production of acid malt; (III) biological acidification of mash and wort in brewing; (IV) bacteriocins produced by LAB in brewing; (V) LAB and anti‐fungal activity; (VI) mycotoxins in cereals.     

从知识产权角度分析养殖中华大鲵产业现状及其健康产品发展方向

中华大鲵是我国特有的珍稀物种和传统的名贵食、药用动物,其肉质鲜美,且肉、骨、皮、内脏、油脂和黏液均含有丰富的生物活性成分,食用与药用价值高。随着中华大鲵人工养殖业的快速发展以及国民生活水平的提高和保健意识的增强,在大鲵野生资源保护及其子二代合理利用的政策法规引导下,具有独特的营养成分和保健功效的养殖中华大鲵高附加值功能产品有着广阔的开发与应用前景。然而,目前我国对养殖中华大鲵生物活性成分的科学研究与精深加工技术相对滞后,对面向大健康的人工养殖中华大鲵资源的开发利用尚处于初步发展阶段。本文以养殖中华大鲵资源开发与利用相关的知识产权为分析对象,从知识产权的申请趋势、技术主题分布、专利质量等多个角度,全面剖析我国养殖大鲵产业的相关研究发展现状,为中华大鲵高附加值功能性健康产品的开发与产业的发展提供参考。     

The Potential of the Incorporation of Essential Oils and Their Individual Constituents to Improve Microbial Safety in Juices: A Review

The juice sector is one of the fastest growing sectors in the food industry. Although juices are important because of their nutritional value and convenience, their composition and physicochemical properties affect their microbiological safety and overall quality during their shelf‐life. Furthermore, the thermal process classically applied in juices partially reduces the occurring microflora, and the use of chemical additives is perceived negatively by consumers. For these reasons, researchers have proposed the use of nonthermal technologies as antimicrobial preservatives in juices. This paper covers the recent literature on the use of essential oils (EOs) and the individual constituents (ICs) found therein, used alone or in combination with other emerging technologies, for the preservation of juices. From this perspective, this paper discusses the growing importance of the use of EOs and their ICs, either alone or in association with other emerging technologies, in juices and their effects on the safety and physicochemical and sensory quality attributes of these products. The results of papers currently available in the literature reveal that EOs and their ICs are promising alternatives to achieve microbial safety and stability in juices. However, extensive studies considering the effects of each EO or IC on sensory characteristics, primarily taste and aroma, are still needed to establish each of these substances/compounds as feasible preservatives for use in juices. Finally, further studies could focus on the combination of low amounts of EOs or ICs with other nonthermal technologies to achieve a balance between the microbial safety and sensory acceptability of juices.     

An assessment towards the acceptance of wearable technology to consumers in Turkey: the application to smart bra and t-shirt products

The study attempts to predict the dynamics that play a role in the process through which consumers accept wearable technology. A research model, in the form of a structural diagram, is proposed in search of the acceptance or buying intention of wearable technology via subjective norms, perceived usefulness, attitude towards the behaviour, perceived behavioural control and the related beliefs. In the study applied to smart bra and t-shirt products, the results show that subjective norms and attitudes towards behaviour are found significant in direct influence to buying intention, but perceived usefulness is not directly related to it. Perceived usefulness and behavioural control are found significant to indirect influence in buying intention through their effects on attitude. In addition, perceived behavioural control is directly related to attitude only for smart bras. In both the products, subjective norms, perceived usefulness, attitude and perceived behavioural control appear to be explained by a set of salient beliefs.     

An approach to the detection of synthetic milk in dairy milk: 3. Detection of vegetable oil and sodium bicarbonate

A high-performance thin layer chromatography (HPTLC) method for the detection of groundnut oil and palm oil, the main constituents of synthetic milk, was developed. The minimum detectable level of the oils was 80 mg/100 ml. The rosolic acid qualitative test was found to be sensitive enough to detect levels as low as 20 mg/100 ml sodium bicarbonate in milk.     

Short communication: An evaluation of the effectiveness of Lactobacillus buchneri 40788 to alter fermentation and improve the aerobic stability of corn silage in farm silos

The objective of this study was to determine if the effects of inoculation with Lactobacillus buchneri 40788 were detectable when applied to whole-plant corn stored in farm silos. Corn silage was randomly sampled from farms in Wisconsin, Minnesota, and Pennsylvania, and was untreated (n = 15) or treated with an inoculant (n = 16) containing L. buchneri 40788 alone or this organism combined with Pediococcus pentosaceus during May and June 2007. Corn silage that was removed from the silo face during the morning feeding was sampled, vacuum-packed, and heat sealed in polyethylene bags and shipped immediately to the University of Delaware for analyses. Silage samples were analyzed for dry matter (DM), nutrient composition, fermentation end-products, aerobic stability, and microbial populations. The population of L. buchneri in silages was determined using a real-time quantitative PCR method. Aerobic stability was measured as the time after exposure to air that it took for a 2°C increase above an ambient temperature. The DM and concentrations of lactic and acetic acids were 35.6 and 34.5, 4.17 and 4.85, and 2.24 and 2.41%, respectively, for untreated and inoculated silages and were not different between treatments. The concentration of 1,2-propanediol was greater in inoculated silages (1.26 vs. 0.29%). Numbers of lactic acid bacteria determined on selective agar were not different between treatments. However, the numbers of L. buchneri based on measurements using real-time quantitative PCR analysis were greater and averaged 6.46 log cfu-equivalents/g compared with 4.89 log cfu-equivalent for inoculated silages. There were fewer yeasts and aerobic stability was greater in inoculated silages (4.75 log cfu/g and 74 h of stability) than in untreated silages (5.55 log cfu/g and 46 h of stability). This study supports the effectiveness of L. buchneri 40788 on dairy farms.