蓝纹干酪成熟期间氨基酸的变化研究

采用HITACHIL—8800型氨基酸自动分析仪测定分析了自制蓝纹干酪成熟过程中的氨基酸组分与含量变化。成熟30～60d期间,所有氨基酸含量都呈现上升趋势,成熟90d时,门冬氨酸、谷氨酸、缬氨酸、蛋氨酸、亮氨酸、苯丙氨酸、精氨酸、脯氨酸几种氨基酸由于转化成其他物质含量有所降低。门冬氨酸降低0.07%,谷氨酸降低0.32%,缬氨酸降低0.09%,蛋氨酸降低0.14%,亮氨酸降低0.22%,苯丙氨酸降低0.02%,精氨酸降低0.07%,脯氨酸降低0.32%。成熟90d时,含量较高的是谷氨酸,亮氨酸,脯氨酸,赖氨酸、酪氨酸。     

电气石复合材料滤嘴棒成形纸降低卷烟烟气有害成分研究

研究了一种含电气石复合材料的卷烟滤嘴棒成形纸的制备及其对降低卷烟烟气有害成分的影响.利用电气石的热电性、压电性和自极化效应产生的电场效应,可对烟气有害成分中的带电物质进行有效吸附.研究结果表明:采用含电气石复合材料的滤棒成形纸可使烟气焦油降低9.93%,CO降低10.27%,酚类物质降低18.28%,NH3降低16.36%,稠环芳烃苯并[a]芘降低25.55%,NOx降低10.61%,HCN降低17.37%.     

适当降低纸张白度实现人与自然和谐发展

为了人类与自然和谐发展,适当降低纸张白度势在必行.通过降低纸张白度,可以降低造纸用浆料白度和增白剂的用量,实现节能降耗;降低浆料白度可以大幅度地降低制浆过程中化学品的消耗、提高制浆原料的利用率、减轻环境污染、提高化机浆的配比,降低纸产品成本,保护人类视力.     

两株嗜酸乳杆菌体外降低胆固醇的研究

考察两株嗜酸乳杆菌体外降低胆固醇的降低曲线和降低方式,以及不同条件下嗜酸乳杆菌对培养基中胆固醇的降低情况.结果表明,这两株茵对胆固醇有明显的去除作用,其对胆固醇的降低作用是同化吸收和共沉淀的结果,以同化方式为主;随着接种量的增加,降低率也随之增加;不同胆盐对其降低胆固醇效果不同,当胆盐添加量为0.2％(m/V)时,胆固醇降低量最大;当吐温80添加量为0.1％时,胆固醇降低效果最佳.     

发芽对黑小麦、黑苦荞淀粉物理化学特性的影响

研究了发芽前后黑小麦、黑苦荞淀粉物化性质的变化.结果表明:发芽后淀粉的粒径大小、形貌未发生变化,黑小麦直链淀粉含量、透明率提高,抗凝沉性变强,65～90℃溶解度、膨胀度变大,析水率降低,糊化温度降低34.7％,峰值黏度降低88.9％,降落值降低60.0％,回生值降低93.6％;黑苦荞直链淀粉、透明率降低,抗凝沉性变差,...     

燃煤锅炉烟气再循技术降低NOx排放研究

文章针对燃煤锅炉烟气再循技术降低NO_x排放进行论述。对我国各地区燃煤锅炉NO_x排放标准进行了总结指出了降低NO_x排放迫在眉睫,并根据NO_x生成机理出发提出烟气再循环降低NO_x原理,最后提出了不同类型锅炉采用烟气再循环技术降低NO_x排放的实例。采用烟气再循环技术可有效降低NO_x含量,为降低NO_x排放提供思路。     

卷烟纸、接装纸和滤嘴丝束对卷烟烟气水分和焦油的影响

研究了不同透气度、不同定量的卷烟纸及不同透气度的预打孔接装纸对卷烟主流烟气水分和焦油的影响.结果发现:①卷烟纸透气度每增加10 CU,水分降低0.122 mg/支,降低率为2.94%;焦油降低0.3 mg左右,降低率约1.93%;②随着卷烟纸定量的增大,烟气水分呈增加趋势,而焦油则呈下降趋势,当卷烟纸的定量大于28 g/m2后,烟气水分的增加和焦油降低的幅度均很小;③预打孔接装纸透气度每增加100 CU,烟气水分降低约0.3 mg/支,降低率12.14%,而焦油则降低1.32 mg,降低率9.7%.因此,从保持烟气水分和降低焦油考虑,卷烟纸的透气度宜小于70 CU,定量应大于28 g/m2;宜采用低透气度接装纸.     

屋面聚氨酯发泡与仓内吊顶综合隔热控温储粮的应用效果

高大平房仓进行屋面聚氨酯发泡、仓内吊顶等隔热处理后,5月中旬至9月底间最高仓温降低3.5℃,仓温平均降低2.8℃;最高上层平均粮温降低3.9℃,平均降低2.7℃;最高全仓平均粮温降低2.1℃,平均降低1.1℃.经过秋冬季机械通风降温,粮堆度夏整仓平均粮温低于16.7℃,上层平均粮温低于27.8℃.     

多孔淀粉在卷烟滤嘴中的应用研究

为探索卷烟减害降焦的新途径,进行了含多孔淀粉的滤嘴、活性炭复合滤嘴和普通醋纤滤嘴的过滤效果对比试验.结果表明,接装多孔淀粉滤嘴的卷烟较普通醋纤滤嘴卷烟的总粒相物降低了3.9%,焦油降低5.4%,CO降低2.7%,烟碱降低3.5%;与活性炭复合滤嘴卷烟相比,总粒相物降低了0.7%.焦油降低3.1%,CO降低2.0%,烟碱未变化.     

微波和高温灭菌对神仙豆活性成分及其抗氧化性的影响

为研究微波和高温灭菌对神仙豆品质的潜在影响,分析了处理前后神仙豆主要活性成分和抗氧化性的变化。结果表明,除总糖和粗纤维含量变化均不显著外(P＞0.05),两种灭菌方式均导致神仙豆活性成分含量的不同程度降低;高温灭菌后,神仙豆氨基酸态氮降低9.52%(P＜0.05),蛋白质降低14.96%(P＜0.05),还原糖降低33.75%(P＜0.05),类黑精降低61.29%(P＜0.05),异黄酮降低5.00%(P＞0.05);微波灭菌后,神仙豆氨基酸态氮降低19.05%(P＜0.05),蛋白质降低1.11%(P＞0.05),还原糖降低28.75%(P＜0.05),类黑精降低70.97%(P＜0.05),异黄酮降低20.00%(P＜0.05);在抗氧化性方面,除对·OH的清除活性外,微波灭菌处理的神仙豆抗氧化性均相对高于高温灭菌组。综合来说,微波灭菌处理的神仙豆抗氧化性相对较高。     

Acceptance of insect-based food in Chile: Evidence from a survey using the entomophagy attitude questionnaire (EAQ)

Research interest in the acceptability of insects as food has dramatically grown in recent years. Investigators have studied the antecedents of people willingness to eat whole insects, processed (non-visible) insects, and insect-fed animals as well. Another important topic is the difference between intention to try insect-based foods once, and readiness to adopt these foods in everyday diet. In 2020, the Entomophagy Attitude Questionnaire has been developed as a tool for researchers in this area. It is the only one self-report questionnaire specific to entomophagy, multi-dimensional, and cross-validated in diverse contexts and languages. The current study contributes to further validate this instrument in Spanish, in a novel context such as Chile, and to expand its nomological validity to intention to eat processed insects. In addition, results show that the three components of the EAQ significantly predict participants’ intention to try insect-based foods and, to a lesser extent, intention to add insect-based food in one own’s diet. Limitations of the study, as well as direction for further research are discussed in the paper.     

Breakdown of intramuscular connective tissue in cod (Gadus morhua L.) and spotted wolffish (Anarhichas minor O.) related to gaping

The purpose of this work was to compare the microstructure of muscle connective tissue in cod and wolffish and to study its degradation during ice-storage to determine which structural alterations are related to the gaping phenomenon. Gaping is very often found in fillets of codfish, but not in wolffish. The results showed that detachments between myofibres occurred prior to the myotomes to myocommata detachments, which occurred more rapidly and to a larger extent in cod than in wolffish. Changes at the ultrastructural level in myocommata proper were mainly related to gaps between collagen fibres and between collagen fibres and cells in the extracellular matrix (ECM). The mean collagen fibre diameter was smaller and the collagen network in myocommata proper was denser in wolffish than in cod. After 7 days of ice-storage the collagen fibres, particular in cod, appeared sparsely packed. The results implied that the increased gaping during ice-storage might be due to degradation of proteoglycans and glycoproteins, important for the spatial organization of the collagen fibres and in anchoring cells in the ECM to the collagen network.     

Grape vine varieties Shiraz and Grenache differ in their stomatal response to VPD: apparent links with ABA physiology and gene expression in leaf tissue

Two cultivars of Vitis vinifera L., namely Grenache and Shiraz, have been described as having near-isohydric and near-anisohydric responses respectively to soil water stress (Schultz, Plant Cell and Environment , 26, 1393–1405, 2003). Given that contrast in sensitivity to soil water, a question arises as to whether atmospheric moisture stress will elicit similar differences. The present study was undertaken to investigate this issue by comparing stomatal responses in these same two cultivars to contrasting vapour pressure deficit (VPD). Test material included field grape vines in the Barossa Valley and pot-grown vines under partial shade in Adelaide. Our experiments showed that the same isohydric/anisohydric distinction as described by Schultz (2003) is apparent in leaf responses to atmospheric moisture stress. In the more isohydric cultivar, Grenache, stomatal conductance is more responsive to changes in VPD. This heightened sensitivity (compared with Shiraz) appears to be associated with higher levels of abscisic acid (ABA) in Grenache xylem sap. Expression studies on the key genes in the ABA biosynthetic pathway indicate that regulation of the V.v . nced1 gene expression in leaf tissue, but not in the root tissues, is associated with the changes in the xylem sap ABA. Moreover, the two cultivars (Grenache and Shiraz) differed with respect to both scale and time course of those responses. We conclude that these two Vitis vinifera cultivars do indeed differ significantly in the way that they respond to potentially stressful atmospheric conditions, and that ABA physiology is a key process in these contrasting responses. An understanding of such mechanisms, including the relative importance of roots and shoots in determining vine response to abiotic stress, is highly relevant to irrigation scheduling, and to management of associated variation in vineyard productivity across diverse environments.     

The mutagenicity and carcinogenicity of hair dyes

A number of the constituents of semi-permanent and permanent hair dyes have been shown to be mutagenic in bacteria, to induce mutation, chromosome breakage, sister chromatid exchanges and malignant transformation in mammalian cells, to cause mutation in Drosophila , to induce mitotic recombination in yeast and to induce tumours in rodents. Some hair dye ingredients and commercial dyes have been shown to give rise, in the urine of treated rats, to metabolites which are also mutagenic in bacteria.
The test systems used are briefly described and the data generated are reviewed. In addition, attempts to identify whether the hazards predicted from the laboratory studies present a risk to man either by epidemiological studies or monitoring of exposed populations are also discussed.
La mutagenese et la carcinogenese des colorants capillaires     

Antioxidant activity determines on‐tree maturation in ‘Golden Smoothee’ apples

BACKGROUND: Harvest date clearly determines the postharvest storage behaviour and sensitivity of fruit to physiological disorders. Generally fruit are picked following their maturity indexes but often these indexes poorly represent the physiological state of the fruit. With this in mind, this work aimed to determine a biochemical marker capable of predicting on‐tree maturation in ‘Golden Smoothee’ apples. Changes in the non‐enzymatic and in enzymatic antioxidant potential of fruit were assessed for different harvest dates. RESULTS: Significant differences in antioxidant levels, especially ascorbate and catalase, were found. These changes were related to climatic variations, especially relating to temperature, that appeared to determine the capability of the fruit to produce ethylene. Fruit exposed to higher temperature produced less ethylene and exhibited a significant delay in the induction of their climacteric. In both seasons, changes in quality parameters during on‐tree ripening were not related to the capability of the fruit to produce ethylene, but rather to endogenous levels of antioxidants, especially catalase and ascorbate, at the earliest picking date. CONCLUSION: We hypothesize that ascorbate and antioxidant activity play a role in changes in maturity patterns exhibited by apples in orchards. Both parameters appear to be interesting markers to follow these changes. Copyright © 2009 Society of Chemical Industry     

Distribution of hydrophilic and lipophilic antibacterial drugs in skim milk,cream, and casein

This study determined the distribution of drugs to different milk fractions according to their physicochemical properties. Hydrophilic drugs tend to concentrate in skim milk, whereas lipophilic drugs tend to concentrate in cream. The concentration of a drug in casein is related to its degree of binding to milk proteins. Thus, we aimed to determine whether withdrawal time in whole milk differs from that in cream, casein, and skim milk. Amoxicillin and tylosin were selected as prototype hydrophilic and lipophilic drugs, respectively. The study was conducted in vitro and in vivo to determine whether in vitro conditions reflect the distribution of drugs in the different milk fractions in vivo. The in vivo study was conducted using a crossover design on 6 healthy Holstein dairy cattle. First, amoxicillin (i.m., single dose, 14 mg/kg) was administered to cows. Following a 1-wk washout period, tylosin (i.m., single dose, 15 mg/kg) was administered. Concentrations of amoxicillin and tylosin in milk and milk fractions were measured using HPLC-UV. In the in vitro study, 0.04 to 400 μg/g of amoxicillin and 0.05 to 50 μg/g of tylosin were spiked to drug-free milk and the concentrations in milk and milk fractions were measured. In addition, the percentage of total protein in milk and milk fractions was determined. Amoxicillin accumulated more in skim milk than in cream and casein, both in vitro (92%) and in vivo (73%, skim milk-to-whole milk ratio). The distribution of tylosin in whole and skim milk was similar to that of amoxicillin in the in vitro study, in contrast to the accumulation of tylosin in cream seen in vivo. However, the accumulation ratio of tylosin in cream was lower than expected. By either method, tylosin was less concentrated in casein than in skim milk and cream. The percentage of total protein was similar in skim milk and whole milk and higher than in cream. Thus, amoxicillin accumulates less in cream and casein, suggesting that these fractions would pose a lower risk to the consumer. Tylosin was still present at the maximum residue limit (50 μg/kg) 24 h after injection in the casein fraction and 48 h after injection in the cream fraction.     

Fluorescence spectroscopy in monitoring of extra virgin olive oil during storage

The present study demonstrates the use of fluorescence spectroscopy for monitoring changes in virgin olive oil during storage. Total luminescence and synchronous scanning fluorescence spectroscopy techniques were tested with the purpose to check their ability to monitor changes occurring in olive oil during storage in different conditions: in clear and green glass bottles exposed to light, and in darkness. Total luminescence spectra of the initial oil samples in n‐hexane solutions exhibited intense peaks, one with a maximum appearing at 320 nm in emission and 290 nm in excitation, attributed to tocopherols, and another appearing at 670 nm in emission and 405 nm in excitation, belonging to the pigments of the chlorophyll group. The intensity of these emissions decreased during storage depending on the storage conditions. Additional bands appeared in oils exposed to light in the intermediate range of excitation and emission wavelengths, arising from unidentified compounds. Bands attributed to tocopherols, chlorophylls and those tentatively ascribed to phenolic compounds were observed in the synchronous scanning fluorescence spectra, allowing monitoring of the storage effects on these constituents and their quantitative assessment after appropriate calibration. The results presented confirm the capability of the fluorescence techniques to monitor the quality of oil products.     

Symposium review: Adipose tissue endocrinology in the periparturient period of dairy cows

The involvement of adipose tissue (AT) in metabolism is not limited to energy storage but turned out to be much more complex. We now know that in addition to lipid metabolism, AT is important in glucose homeostasis and AA metabolism and also has a role in inflammatory processes. With the discovery of leptin in 1994, the concept of AT being able to secrete messenger molecules collectively termed as adipokines, and acting in an endo-, para-, and autocrine manner emerged. Moreover, based on its asset of receptors, many stimuli from other tissues reaching AT via the bloodstream can also elicit distinct responses and thus integrate AT as a control element in the regulatory circuits of the whole body's functions. The protein secretome of human differentiated adipocytes was described to comprise more than 400 different proteins. However, in dairy cows, the characterization of the physiological time course of adipokines in AT during the transition from pregnancy to lactation is largely limited to the mRNA level; for the protein level, the analytical methods are limited and available assays often lack sound validation. In addition to proteinaceous adipokines, small compounds such as steroids can also be secreted from AT. Due to the lipophilic nature of steroids, they are stored in AT, but during the past years, AT became also known as being able to metabolize and even to generate steroid hormones de novo. In high-yielding dairy cows, AT is substantially mobilized due to increased energy requirements related to lactation. As to whether the steroidogenic system in AT is affected and may change during the common loss of body fat is largely unknown. Moreover, most research about AT in transition dairy cows is based on subcutaneous AT, whereas other depots have scarcely been investigated. This contribution aims to review the changes in adipokine mRNA and—where available—protein expression with time relative to calving in high-yielding dairy cows at different conditions, including parity, body condition, diet, specific feed supplements, and health disorders. In addition, the review provides insights into steroidogenic pathways in dairy cows AT, and addresses differences between fat depots where possible.     

Adaptation to Climate Change by Smallholder Farmers in Rural Communities: Evidence from Sri Lanka

The agricultural sector plays a key role in Sri Lankan economy, whose major source of livelihoods is smallholder farming in paddy and vegetable cultivation which is highly vulnerable to climate changes having negative impact on food security. To overcome the welfare losses, the smallholder farmers need to identify the changes in climatic variables and adjust to their farming practices to cope up with the climate change. Thus, this study examines how rural smallholder farmers in different agro-ecological zones in Sri Lanka perceive climate change and accordingly adapt to it in their agricultural practices. A questionnaire survey was conducted with a random sample of 125 farmer households distributed in most vulnerable four agro-ecological zones namely, Belihuloya, Ihala Galagama, Mulgama and Kosgama in up country inter mediate zone. The study shows that all the respondents have observed rising trends in temperature and winds and lack of adequate rainfall during last twenty years and in response they have grown short season crops as the main farming practice to adapt to minimize the potential losses on their yields. The results of the logistic regression revealed that social economic factors, environmental factors, institutional factors and the economic structure influence farmers’ choice of adaptation methods to climate change. The size of the household, income, education, accessibility to climate information through television and radio, being a member in farmers’ group, location of the land, crop variety, access to formal loans and distance to input markets had significantly affected adaptation. For instance the farmers who grow beans as the major crop to adapt to climate change has 94% probability with compared to those farmers who do not grow other crops whereas the farmers who come to know the changing patterns of the climate through television and radio have a higher probability (94%) of adaptation to the climate change than those who use other media. Sri Lankan government requires facilitating the smallholder farmers to overcome the constraints in which they face in using adaptation methods to climate change so that the welfare of the farmers and growth of the agricultural sector can be ensured.     

2016—2020年国际食品法典委员会大会有关水产品标准议题的跟踪分析及启示

水产品作为我国最重要的出口产品种类, 为防范和应对国外技术性贸易壁垒, 有必要及时跟踪和掌握国际食品法典委员会水产品相关标准议题的制修订情况。本文梳理了2016—2020年CAC第39~43届大会上审议的水产品标准议题, 并着重分析了我国重点关注议题的讨论和解决情况。2016—2020共有23项涉及水产品法典标准的制修订成果经CAC大会审议通过。我国主要关注和参与鲟鱼子酱、组胺、紫菜和沙丁鱼罐头等标准议题。目前, 我国在CAC水产品标准制修订话语权、CAC水产标准化工作参与度、科学技术支撑国际标准化等方面还有不足。为推进我国水产国际标准化建设, 在CAC水产品标准起草中争取更高地位。提出抓紧研究主持制定CAC标准的机制, 努力提升参与CAC水产品标准工作的深度和范围, 并持续重视和深化科学技术研究与标准化的统一等建议。