储藏期与储藏压力对稻谷籽粒压缩特性的影响研究

利用质构仪压缩稻谷籽粒的短轴来测定稻谷籽粒的压缩特性。测定的稻谷储藏在不同的时间与压力下。实验结果表明:当储藏时间为60 d且储藏压力由0 kPa增加到300 kPa,稻谷籽粒的破坏力由81.6 N减小到73.8 N,破坏能由8.10 mJ减小到6.27 mJ,破坏应变由0.139减小到0.117,表观接触弹性模量由171.3 MPa减小到57.7 MPa,最大接触应力由40.8 MPa减小到19.1 MPa。当稻谷储藏压力为77、100、139、200 kPa且储藏时间由0～60 d,稻谷籽粒的破坏力由81.6 N分别减小到79.6、79.1、78.2、77.0 N;破坏能由8.10 mJ分别减小到7.55、7.35、7.08、6.85 mJ;破坏应变由0.139分别减小到0.131、0.128、0.126、0.121;表观接触弹性模量由171.3 MPa分别减小到136.0、121.8、110.6、83.3 MPa;最大接触应力由41.2 MPa分别减小到35.0、32.5、30.3、15.0 MPa。结果表明储藏压力与储藏时间对稻谷籽粒的压缩特性有重要的影响。     

国内外大豆加工业生产现状与发展趋势

结合工作与生产实际，在查阅和调研了国内外大豆加工业相关资料和项目之后，对生产现状进行了简要表述，对发展趋势进行了粗浅分析。明确指出：国外大豆加工业的发展趋势是原料生产与产品研发同步进行，努力抢占国内外市场，开发传统品牌产品，加强宣传工作力度，瞄准“三高”产品，增加社会经济效益，组建发挥社会团体作用，推动大豆产业发展。国内发展趋势是注重快餐型大豆食品生产，适应消费人群生活特点，注重大豆蛋白功能性的研发，满足国内市场需要，注重油脂加工业合理布局，扩大相关产业向前发展，以此发挥优势和强项，打造具有中国特色的与世界同步发展的大豆加工产业。     

Determination of mineral content in polymelt nonwoven fabrics

Minerals have been widely added to polyolefins during film- or fiber-manufacturing process to improve the processibility as well as to enhance the product properties such as thermal conductivity, surface roughness, fabric filtration efficiency, and fabric capacity of oil absorbency. Titanium dioxide has been traditionally added in PET fibers as a delustrant to reduce their transparency for some applications, e.g. clothing materials. Calcium carbonate has recently been added in polymelt – spunbond and meltblown – fibers to increase the fiber processibility and to improve the fiber properties and hence to achieve their final performance. It is crucial that the adding quantity should be controlled so the fabric strength will not be adversely reduced. Calcium carbonate is frequently over-added in polymelt fibers to take the advantage in business trading by weight. A method is essential to determine the mineral content in the polymeric materials. While trying to use the volume of the fabrics displaced by liquid to determine the density of fibers fails, we successfully used buoyant force of the fabrics in a liquid to precisely determine the volume of the fibers and to use it to calculate the mineral content in spunmelt PP fabrics. A gadget was designed to incorporate with a balance to form a density balance for this research. It was observed that only a single layer but not multiple layers of fabric is a key point to accurately determine its buoyancy in the liquid. Multiple layers contributed to a relaxation of the bending forces at the folding lines of the fabric, which attributed to an error in measuring the buoyancy of the fabric.     

A PNA-array platform for the detection of hidden allergens in foodstuffs

A duplex PCR method was developed to simultaneously detect the presence of hazelnut and peanut in raw materials and commercial products. It was found to be able to specifically detect traces of the investigated products down to 50 pg of their target DNA.A PNA array device has been designed and implemented to be used in combination with the duplex PCR in order to investigate the presence of traces of potentially allergenic nuts in foodstuffs. A PNA probe for each target amplified by the duplex PCR was designed, synthesized and characterized. The PNA probes were then deposited on commercial slides in order to build a PNA array to be used for recognizing the PCR products; the concentration of the probes as function of the concentration of the target DNA, together with the specificity of the probes were investigated.The conditions optimized during the setting of the experiment were used to obtain the final version of the PNA array which was then used to test several commercially available foodstuffs claiming to contain or not to contain the targeted nuts.     

Kinetics of the Benzylation of Potato Starch

The formation of benzyl ethers of potato starch by etherification with benzyl chloride is base catalyzed and is therefore carried out at high pH. In a suspension of starch granules the rate of starch ether formation is found not to be linearly related to the concentration of hydroxyl ions in the water phase of the suspension. At the same pH widely different rates of reaction can be observed, to be due to the tendency of the starch granules to “absorb” hydroxyl ions when electrolytes are added to the suspension. The rate of formation of the benzyl ether of starch is found to be linearly related to the amount of hydroxyl ions “absorbed” by the starch. The rate of the side reaction leading to benzyl alcohol turned out to be higher in the presence of starch than in water of the same pH.     

当代博物馆展陈设计表现形式的研究

为了能充分发挥博物馆的功能及满足人们对历史文化的需求,博物馆的展陈设计发挥着重要作用。同时,为了能适应世界经济的快速发展,也为了博物馆趋于可持续和完美化,当前还存在的一些问题必须解决,因此高科技的使用、多样化功能的使用、节能环保的利用等多元化元素逐渐的被引入到博物馆中。这是博物馆的需要,也是时代的需求。     

The influence of attachment to beef surfaces on the survival of cells of Salmonella enterica serovar Typhimurium DT104, at different a(w) values and at low storage temperatures

This study investigated the influence of attachment to beef surfaces on the survival, injury and death of stationary phase cells of Salmonella enterica serovar Typhimurium DT104, compared to cells free in solution. The effects on cells are considered at different a(w) values and low temperatures in relation to osmotic and cold temperature shock effects. Attachment of cells to meat surfaces prevented cell injury and death from hyperosmosis and low temperatures, compared to meat solutions. Storage of cells for 72h resulted in higher levels of cell death on cells attached to meat surfaces. The improved survival of cells in solutions was considered to be related to adaptation to osmotic stress as a result of exposure to a previous hyperosmotic shock and the ability of the cells to produce cold shock proteins. Pathogen cell growth at low temperatures is discussed in relation to the presence of low levels of NaCl. Finally the data is discussed in relation to pathogen survival on beef carcass surfaces during refrigeration.     

New procedure for the study of odour representativeness of aromatic extracts from smoked salmon

The representativeness of an aromatic extract of smoked salmon obtained from simultaneous steam distillation and extraction with diethyl ether is discussed. After extraction, the extract is diluted in ethanol with an evaporation of diethyl ether, which allows the extract to be redeposited on matrices physically similar to those of the original product. When the shift of the matrix effect is taken into account, the sensorial results are closer to reality and more representative of the real interaction conditions between the matrix and the extract. Several sensory methods are used to describe the representativeness of the smoked salmon extracts, such as triangular and notation tests. Preliminary work is carried out on standards known both to contribute to the aroma of many seafood products and to have a high volatility in comparison with those expected in smoked salmon in order to test the method in difficult conditions of recovery. This enables the recovery yield of the extraction (from 62% for limonene to 97% for 2-methylphenol) to be assessed leading to a better characterization of the representativeness taking into account the odour dilutions. The final aromatic extract is found to be about 70% representative of the original product.     

Calculating Quantities of Ice for Cooling and Maintenance of Freshly Harvested Fish at Sea

Abstract: A new generalized model for predicting quantities of ice to cool and maintain freshly harvested fish at sea in insulated boxes is presented. The model addresses the universal need for fisherman to know in advance of going to sea just how much ice will be needed to cool down the expected day's catch to a desired temperature, maintain the catch, and to allow for losses. Illustrative predictions are presented for southern bluefin tuna (SBT) (Thunnus maccoyii) for a range of day's catch from 2000 to 8000 kg in ambient temperature ranging from 15 to 35 °C. The amount of ice needed to cool down SBT from an initial uniform harvest temperature of 28 °C to a maintenance temperature of 5 °C is shown to be the controlling contribution to total ice needed. Predictions highlight that a useful, safe rule‐of‐thumb is 1 kg of ice will be needed for each 3.5 kg of SBT. Importantly, the model is based on fundamental principles and predictive accuracy is demonstrated to be largely insensitive to a range of assumptions including volume of the void in the insulated boxes and overall coefficient of heat influx from ambient. The model can be used to predict the number of insulated boxes of defined dimension that will be needed to cool and hold the fish, ice and water for a wide range of fish species. It will be of interest to fisherman and boat owners and agents who invest in ice to preserve fish at sea. Practical Application: This research addresses the universal need for fisherman to know in advance of going to sea how much ice will be needed on‐board boats to cool down an expected day's catch to a desired temperature, maintain the catch and to allow for losses. The model is generalized and can be applied to a wide range of fish species.     

Predictive microbiology: providing a knowledge-based framework for change management

This contribution considers predictive microbiology in the context of the Food Micro 2002 theme, "Microbial adaptation to changing environments". To provide a reference point, the state of food microbiology knowledge in the mid-1970s is selected and from that time, the impact of social and demographic changes on microbial food safety is traced. A short chronology of the history of predictive microbiology provides context to discuss its relation to and interactions with hazard analysis critical control point (HACCP) and risk assessment. The need to take account of the implications of microbial adaptability and variable population responses is couched in terms of the dichotomy between classical versus quantal microbiology introduced by Bridson and Gould [Lett. Appl. Microbiol. 30 (2000) 95]. The role of population response patterns and models as guides to underlying physiological processes draws attention to the value of predictive models in development of novel methods of food preservation. It also draws attention to the paradox facing today's food industry that is required to balance the "clean, green" aspirations of consumers with the risk, to safety or shelf life, of removing traditional barriers to microbial development. This part of the discussion is dominated by consideration of models and responses that lead to stasis and inactivation of microbial populations. This highlights the consequence of change on predictive modelling where the need is now to develop interface and non-thermal death models to deal with pathogens that have low infective doses for general and/or susceptible populations in the context of minimal preservation treatments. The challenge is to demonstrate the validity of such models and to develop applications of benefit to the food industry and consumers as was achieved with growth models to predict shelf life and the hygienic equivalence of food processing operations.     

The effect of storage pressure on the mechanical properties of paddy grains

To investigate the effect of storage pressure and storage time on the mechanical properties of paddy grains, an experimental study was carried out to determine the mechanical properties of paddy grains compressed at minor axis orientation using the Texture Analyzer. The paddy grains were stored under different pressures and for different time. The results showed that as the storage pressure increased from 0 to 300 kPa, the rupture force of paddy grains stored for 60 days decreased from 81.58 to 73.78 N, the rupture energy from 8.10 to 6.27 mJ, the rupture strain from 0.1392 to 0.1168, the apparent contact modulus of elasticity from 171.32 to 57.68 MPa and the maximum contact stress from 40.84 to 19.11 MPa. All of the mechanical properties of the paddy grains exhibited a linear relationship with storage pressure. As for the paddy grains stored under the pressures of 77, 100, 139, 200 kPa, as the storage time increased from 0 to 60 days, the rupture force of the paddy grains decreased from 81.58 to 79.58 N, 81.58 to 79.12 N, 81.58 to 78.21 N and 81.58 to 76.96 N; the rupture energy decreased from 8.10 to 7.55 mJ, 8.10 to 7.35 mJ, 8.10 to 7.08 mJ and 8.10 to 6.85 mJ; the rupture strain decreased from 0.1392 to 0.1309, 0.1392 to 0.1283, 0.1392 to 0.1257 and 0.1392 to 0.1213. The apparent contact modulus of elasticity decreased from 171.32 to 135.97 MPa, 171.32 to 121.77 MPa, 171.32 to 110.59 MPa and 171.32 to 83.32 MPa; the maximum contact stress decreased from 41.16 to 35.00 MPa, 41.16 to 32.45 MPa, 41.16 to 30.32 MPa and 41.16 to 14.97 MPa, respectively. The results revealed that both storage pressure and storage time have a significant effect on the mechanical properties of paddy grains.     

Reaction mechanism for chlorination of urea

Experiments were conducted to elucidate the mechanism of the reaction between free chlorine and urea. In combination with findings of previous investigations, the results of these experiments indicate a process by which urea undergoes multiple N-chlorination steps. The first of these steps results in the formation of N-chlorourea; this step appears to require Cl? to proceed and is the overall rate-limiting step in the reaction for conditions that correspond to most swimming pools. N-Chlorourea then appears to undergo further chlorine substitution; the fully N-chlorinated urea molecule is hypothesized to undergo hydrolysis and additional chlorination to yield NCl? as an intermediate. NCl? is hydrolyzed to yield NH?Cl and NHCl?, with subsequent decay to stable end products, including N? and NO??. Conversion of urea-N to nitrate is pH-dependent. The pattern of nitrate yield is believed to be attributable to the fact that when urea serves as the source of reduced-N, entry into the reactions that describe chlorination of ammoniacal nitrogen is through NCl?, whereas when NH? is the source of reduced-N, entry to these reactions is through NH?Cl.     

Browning response of fresh-cut apples of different cultivars to cold gas plasma treatment

The present work aims to study the effects of cold gas plasma on some quality parameters of apple slices belonging to four different cultivars (Pink Lady®, Fuji, Red Delicious and Modì®), with particular attention to polyphenoloxidase (PPO) inhibition and related changes in colour and visual quality.Upon plasma exposure a noticeable reduction of superficial browning was observed in all cultivars but not always proportionally to treatment time; the effect on PPO activity was very variable and not correlated to the effect on enzymatic browning. Textural parameters were affected by plasma treatments only in Red Delicious apples. Generally, the response of the tissue to the treatments was variable according to the cultivar considered. The results obtained in this study indicate the necessity of further investigation about consequences of plasma treatment on specific tissue physiology in order to choose the better treatment parameters, optimizing its effect for the specific final product.Industrial relevanceThe application on cold plasma to minimally processed fruit and vegetable has shown a good potential for enzymatic browning inhibition making it an interesting alternative to traditional dipping methods. Nevertheless, the effect on the tissue to the exposure to plasma active particles is not fully known yet. For the industrial application of the treatment, the response for example of different cultivars to the treatment is of high importance, in the first place for the selection of the more appropriate raw material but also to eventually adapt the process parameters to the specificity of the matrix.     

Effect of heat and autoclave on allergenicity of porcine serum albumin

This study was performed to investigate the effects of heat and autoclave treatment on the binding ability of porcine serum albumin (PSA) to IgG and the serum of patients who were allergic to pork. Heat treatment at 100°C for 20 min on PSA was able to decrease the binding ability of PSA to IgG to 52%. The binding ability of PSA to IgG was also reduced to 29% by autoclave treatment of PSA at 121°C for 30 min. The binding ability of PSA autoclaved for 30 min to serum also decreased to 10%. SDS-PAGE and immunoblotting of PSA heated at 100°C for 20 min revealed that the intensity of the PSA band decreased and its presence was barely recognized by IgG. In the case of autoclave treatment (for 5 min), PSA was degraded to low-molecular-weight peptides and IgG and serum did not recognize them. Therefore, autoclave treatment can effectively reduce the allergenicity of PSA.     

食品安全在企业财务绩效中的功能作用及实现路径

食品企业所具有的食品安全保障能力,必然促使其利益相关方作出能够影响企业利益的行为选择,最终通过企业的财务绩效反映出来。通过对食品安全在企业财务绩效中功能的审视,可以发现食品安全通过影响消费者、政府以及社会舆论等利益相关者对其产品的态度,能够对其财务绩效起到相应的提升作用。因此,财务绩效具有促进食品企业履行食品安全保障责任的功能。然而,由于诸多因素的影响,财务绩效促进企业履行食品安全保障责任的功能可能出现失范。这些因素包括短期绩效和长期绩效之间的矛盾、信息披露制度欠缺,以及食品企业社会责任意识缺失等。因此有必要通过相应的路径,采取针对性的措施,以构建财务绩效促进食品企业履行食品安全保障责任功能的机制。     

精梳毛纱细度偏差的控制

细度偏差是精梳毛纱评等考核的重要指标之一,为使最终成品细度非常接近客户的要求,增强产品的市场竞争力,关键要确定好精纺机设计细度,同时要控制好细度偏差。文章主要介绍了运用最小二乘法确定毛纱的设计细度及运用平均值一极差控制图对毛纱细度进行有效管理的方法,使精纺机的生产过程达到统计控制状态,及时发现细度异常变化,降低毛纱细度偏差,提高毛纱质量。     

抗运动性疲劳营养补剂的研制

在体育训练和比赛中,运动员不论是在力量、速度、耐力和灵巧等方面都体现了强度大、难度高的特点,精神紧张,体力大量消耗,机体的各个系统都会发生不同的变化和反应,运动时体内激素分泌增加,物质代谢加强,能源物质被大量消耗,酸性代谢产物积聚加快,导致机体内环境发生一系列的变动。特别是在大运动量训练和激烈的比赛中,疲劳是不可避免的。这时机体对营养素的需求量必然发生某些改变。为了适应大运动量和高强度的专业化训练,仅靠平衡膳食是无法满足专业训练所消耗的大量能源物质,必须使用功能性的运动营养补剂来帮助运动员提高耐久力以及恢复体力和运动能力,以帮助运动员承受更大的训练压力和适应更大的额外训练应激,此外,运动营养补剂还可以帮助运动员提高自身内源性物质的合成水平。     

Household trials with very small samples predict responses to nutrition counseling intervention

Household trials were conducted to test the acceptability and feasibility of the recommendations to be delivered to the mothers in the context of a randomized intervention implemented in Pelotas, Brazil. A first home visit was paid to assess child health and feeding problems. In a second visit, the mother was encouraged to select one or two recommendations to try out over five days. The last visit was used to assess the mothers' experiences in attempting to implement the recommendations. Nonexclusive breastfeeding, use of the bottle, monotonous diet, and low energy density of foods were the most common problems. The most frequently selected recommendations were those aiming to increase the energy density of foods. Mothers generally reported positive responses to the recommendations. The household trials highlighted the acceptability and feasibility of the planned recommendations and correctly predicted the changes that were successfully implemented by the mothers in the large intervention study.     

How do different warning signs compare with the guideline daily amount and traffic-light system?

Nutritional warnings are rapidly gaining relevance, particularly in the region of the Americas, as a front-of-package nutrition labelling scheme that facilitate the identification of products with high content of nutrients associated with non-communicable diseases (NCDs). Several graphic designs are being developed as countries discuss the implementation of nutritional warnings, which makes it necessary to develop research to evaluate their efficacy. In this context, the aim of the present work was to compare the efficacy of a series of nutritional warnings that are being considered by Brazilian national authorities for the country with two of the most studied schemes: the guidelines daily amounts (GDA) and the traffic light system. Two studies were conducted. In the first one, visual search was conducted with 62 participants to evaluate the time needed by them to identify the schemes on food labels and to identify whether a product had high nutrient content. In the second study, an online survey with 1932 participants was used to evaluate their ability to use FOP nutrition labelling schemes to correctly identify the most healthful product in a set, as well as high nutrient content in a product. In addition, the influence of FOP nutrition labelling schemes on perceived healthfulness was evaluated. Finally, consumers’ perception of the schemes was gathered using an open-ended question. Results confirmed the advantages of nutritional warnings compared to the GDA and the traffic-light system to facilitate the identification of products with high content of nutrients associated with NCDs. In addition, the use of familiar signs frequently used to convey a ‘warning message’ outperformed other unfamiliar signs in terms of their ability to facilitate the interpretation of nutrition information. Regarding colour, black signs tended to required significantly less time to be detected when included on colour food labels compared to red signs.     

谈面粉企业的标准化体系

面粉企业的标准化是企业推行ISO9001质量认证的基础，其标准化工作要以满足市场需要的、质量稳定的小麦粉生产为重点；以小麦粉质量标准为工作核心、健全面粉企业的标准化体系。通过完善关键技术标准，加强标准化工作的实施，以规范企业小麦粉生产技术行为，推动小麦粉生产健康发展，迎接“入世”挑战。