单宁的理化性质及其应用研究

单宁是一种多元酚类化合物,具有十分重要的利用和开发价值。本文主要综述了单宁的自然来源、理化性质、提取技术及应用,为单宁的进一步开发和利用提供参考。     

Determination and control of the moisture and salt content of butter

Work is described on on-line meters for the moisture content and salt content of butter from a continuous buttermaker. It is shown that the moisture meter gives a very accurate estimation of the rapid moisture test value, and the salt meter accurately estimates the reference salt value. The incorporation of the meters, together with a moisture and salt controller, has allowed the mean moisture content of butter to be increased by approximately 0.16%, and the mean salt content of butter has increased by 0.12%. This increase represents a considerable financial saving.     

牛仔布丝光染色的理论与实践

丝光牛仔布是传统牛仔布的基础上，采用纱线表面丝光工艺，而获得表层色浓，内层洁白，对比鲜明的高质量环染效果，其色泽鲜艳度，深度较常规牛布要好得多，文章介绍了丝光牛仔用纱，丝光，染色，上浆的理论与生产实践及其注意事项，成本核算等。     

氧氟沙星完全抗原的合成鉴定及其单克隆抗体的制备纯化

本试验通过碳二亚胺(EDC)法把氧氟沙星(OFLX)与载体蛋白BSA和OVA分别进行偶联制备免疫抗原和包被抗原,并采用紫外扫描法和SDS-聚丙烯酰胺凝胶电泳方法对合成抗原进行了鉴定。通过杂交瘤常规技术获得了抗OFLX的单克隆抗体杂交瘤细胞株7株,用辛酸-硫酸铵法对腹水进行了纯化。纯化腹水均属IgG1型。经过ELISA方法鉴定,纯化后的抗体效价>1:128000;交叉实验证明所得抗体与达氟沙星、洛美沙星、环丙沙星、诺氟沙星、卡那霉素、庆大霉素、泰乐菌素均没有交叉反应,表现了良好的敏感性和特异性。     

红树莓的医疗保健作用及红树莓饮料的开发

主要介绍了红树莓含有的花青素、鞣化酸、黄酮、水杨酸等营养成分,并重点阐述了红树莓在抗衰老、抗心血管疾病、抗癌等方面的医疗保健作用。同时为了尽可能保留红树莓的全部营养成分,采用正交实验研制了红树莓果肉果汁饮料,为人们提供一种高价值的健康饮品。     

Predictive modelling of growth and measurement of enzymatic synthesis and activity by a cocktail of selected Enterobacteriaceae and Aeromonas hydrophila

The possibility was examined of developing a predictive model that would predict food spoilage by combining microbial growth (increase in cellular number) with extracellular enzymatic activity of a cocktail of five strains of Enterobacteriaceae: Escherichia coli, Enterobacter agglomerans, Klebsiella oxytoca, Klebsiella pneumoniae and Proteus vulgaris and one Aeromonas hydrophila strain. Estimations of growth and enzyme activity were made within a three-dimensional matrix of conditions: temperature 2-20 degrees C, pH value 4.0-7.5 and water activity (a(w)) 0.95-0.995. A mathematical model was constructed which predicted growth based on increases in cell number. However, although notable effects of extracellular lipases and proteases were detected, it was not possible to model enzymatic activity and prepare a combined model because the data did not follow the characteristic profile that would allow curve-fitting. Nevertheless, the model for microbial growth and information relating to enzyme activity will be made freely available in a database on the internet.     

A comparison of the extent and site of energy and protein digestion of wheat,lupin and meat and bone meal by pigs

The ileal digestibilities of dry matter (DM), nitrogen (N), energy and amino acids were measured using pigs prepared with either re-entrant or simple ileal cannulae and fed a basal wheat diet, a wheat/lupin diet and a wheat/meat and bone meal (MBM) diet. The same pigs were also used to determine the faecal digestibilities of DM, N and energy in these diets. Addition of lupins to the basal diet had no significant effect on the true digestibilities of amino acids but addition of MBM significantly ( <0.01) reduced amino acid digestibility. It was calculated that an average of about 90% of the amino acids in lupin and wheat but only 65% of those in MBM were absorbed from the stomach and small intestine of the pig. Compared to lupin and wheat, a much larger proportion of the protein in MBM disappeared in the large intestine (approximately 4, 6 and 15% respectively). On the other hand, a large proportion of the energy in lupins but little of that in wheat and MBM (32, 8 and 4% respectively) disappeared in the large intestine. There were no significant differences between the re-entrant and simple cannulae for ileal digestibility values of DM, N and amino acids.     

Strength and stiffness of ring and shear-plate connections

The development of Eurocode 5, the future European timber design code which is based on the partial safety coefficient method, means a change of timber design code formats in a number of European countries. Because of the change in the code format from allowable values towards partial safety coefficients, characteristic values of strength and stiffness of materials and connections are needed. In order to establish characteristic values of the strength and stiffness of ring and shear-plate connections, existing test data have been evaluated. The results of the evaluation correspond well to a mechanical model assuming a shear block failure of the wood as the governing failure mode.     

Effect of cold storage and freezing of bovine and porcine liver on activity and subcellular distribution of mitochondrial enzymes

The subcellular distribution of the mitochondrial enzymes lipoamide dehydrogenase (LIPDH), citrate synthase (CS), and beta-hydroxyacyl-CoA-dehydrogenase (HADH) in bovine and porcine liver tissue was studied by measuring the enzyme activities in a phosphate buffer extract of tissue (total activity) and in liver press-juice (cell plasma). In slaughter-fresh liver most of the activity was located in the mitochondria. During storage of liver under refrigeration (+2 degrees C) for several days a large decrease in total LIPDH activity and a lesser decrease in HADH activity, but no change in CS activity were observed. There was no or only little release of the three enzymes into the cell plasma during storage; this indicates that storage of liver at +2 degrees C was not accompanied by a marked damage of mitochondria. Freezing (-20 degrees C) and thawing of bovine and porcine liver caused some losses of the total activity of HADH and particularly of LIPDH but not changes in CS activity. There was a considerable increase in the activities of LIPDH, CS, and HADH in the press juice after freezing and thawing of liver tissue. Apparently freezing of liver results in damage to the mitochondria and, therefore, in a partial release of the three enzymes from the inner membrane of the mitochondrion into the cell plasma. By storage of liver under refrigeration the mitochondria became more sensitive to freezing and thawing. Prolonged frozen-storage of liver resulted in an increased release of LIPDH, CS, and HADH into the cell plasma.     

Theoretical and practical problems of nutrition of healthy and sick individuals

Disorder of lows of a nutrition of healthy and sick person results in diseases, to a disability, reduction of lifetime and premature mors. There are 4 laws work of nutrition by healthy and sick person are submitted. The basic dietology ways of correction of illness are discussed.     

Effects of pH and concentrations of linoleic and linolenic acids on extent and intermediates of ruminal biohydrogenation in vitro

Three experiments were conducted by in vitro incubations in ruminal fluid to investigate the effects of pH and amounts of linoleic and linolenic acids on the extent of their biohydrogenation, the proportions of conjugated linoleic acid (CLA) and trans-C18:1 as intermediates, and the ratio trans-10:trans-11 intermediates. The effects of pH and amount of linoleic acid were investigated in kinetic studies, and effects of the amount of linolenic acid were studied with 6-h incubations. With identical initial amounts of linoleic acid, its disappearance declined when the mean pH during incubation was under 6.0 compared with a mean pH over 6.5, and when the amount of linolenic acid increased from 10 to 180 mg/160-ml flask, suggesting an inhibition of the isomerization step of the biohydrogenation. Low pH decreased the ratio of trans-10:trans-11 intermediates. With initial amounts of linoleic acid increasing from 100 to 300 mg, the percentage of linoleic acid disappearance declined, but the amount that disappeared increased, without modification of the trans-10:trans-11 ratio, suggesting a maximal capacity of isomerization rather than an inhibition. Moreover, increasing initial linoleic acid resulted in high amounts of trans-C18:1 and an increase of C18:0 that was a linear function of time, suggesting a maximal capacity for the second reduction step of biohydrogenation. High amounts of initial linolenic acid did not affect the amounts of CLA, trans-C18:1, or the ratio trans-10:trans-11. Based on these experiments, a ruminal pH near neutrality with high amount of dietary linoleic acid should modulate the reactions of biohydrogenation in a way that supports CLA and trans-11C18:1 in the rumen.     

异淀粉酶产生菌的分离鉴定及异淀粉酶基因的克隆表达

目的:为了进一步提高淀粉的利用率,从微生物中获得高产量异淀粉酶的菌株。方法:本实验从富含淀粉的土壤中筛选出1株高产异淀粉酶的菌株,命名为LZ-5,通过菌落形态观察、生理生化特性实验、16S rDNA序列及gyrB基因分析,构建系统发育进化树并对其进行鉴定;根据NCBI上的迟缓芽孢杆菌(Bacillus lentus)异淀粉酶基因设计引物,扩增出异淀粉酶基因后,以pMD-18T为载体,构建重组质粒,导入到E.coli DH5a感受态细胞,挑选阳性重组质粒进行酶切鉴定及表达产物的检测。结果:LZ-5鉴定为枯草芽孢杆菌,所产异淀粉酶酶活力为10.9 U/mL;测序结果与NCBI上报道的异淀粉酶基因相似度达到96%,表明将枯草芽孢杆菌的异淀粉酶基因成功转化到大肠杆菌中。经IPTG诱导表达,构建的大肠杆菌工程菌,通过细胞破碎仪破碎后,测得异淀粉酶酶活力为28.4 U/mL,是菌株LZ-5的2.6倍。结论:细菌异淀粉酶基因重组表达是解决异淀粉酶活力低的主要策略之一。     

Production and Characterization of an Enzymatic Hydrolysate of Skim Milk Lactose and Proteins

Enzymatic hydrolysis of skim milk lactose and proteins was investigated in a batch reactor; the final aim is to produce a predigested dietary product. The use of yeast β-galactosidase, a vegetable protease, a fungal protease, and a bacterial protease was investigated. Sequential and simultaneous lactose and protein hydrolysis were studied in order to diminish incubation times. In the lactose hydrolysis, 90% conversion was obtained after 4 hr using reconstituted spray-dried skim milk, and after 3 hr using fluid pasteurized skim milk. In the simultaneous hydrolysis, 82% lactose hydrolysis and a substantial peptide hydrolysis with 80% of material smaller than 5,000 molecular weight (and high in small peptides) was obtained after 5 hr. This was adequate for the preparation of a specialized dietary product to be used in enteral hyperfeeding.     

Microstructure and Water Uptake of Phaseolus and Winged Beans

The role of seed microstructure in initial water uptake during the soaking of Phaseolus and winged bean seeds was investigated. Considering their relatively small area, hilum and micropyle seemed to be the most important structural features influencing the initial water uptake. Seed coat played a dominant role only after its initial resistance to water uptake was overcome. Varieties with high initial water uptake also had relatively thin seed coats, a loosely arranged cell structure on the raphe-side of the hilum, a deeply grooved hilar fissure, and a narrow tracheid bar. Water absorption in legumes appeared to be a complex process with the seed coat, hilum and micropyle together constituting an integrated water absorption system.     

Effect of lactic fermentation and extrusion of bean and pea seeds on nutritional and functional properties

Controlled lactic acid fermentation of „Bomba”︁ bean and „Opal”︁ pea was used to improved their nutritional and functional properties. The modified legumes were used as a source for extrusion process to obtain snack-type foods. Milled legume seeds were fermented by different population of Lactobacillus plantarum with different moisture content in plant material to estimate the influence of this two parameters on the dynamics of lactic fermentation. Quantitative and qualitative changes in carbohydrates and nitrogen compounds of modified seeds were analyzed (e.g . mono- and oligosaccharides, "in vitro" starch and protein digestibility). In the new snack-type products, functional properties: water solubility index (WSI), water absorption index (WAI), expansion index, bulk density and texture explained as a shearing stress were recorded. Results showed a distinct decrease in raffinose, verbascose and stachyose contents even up to 80 - 90% after fermentation and extrusion process. Lactic fermentation and extrusion of bean and pea seeds contributes to a significant (a ≤ 0,05) increase of "in vitro" protein and starch digestibility. Observations of changes in functional properties of extruderates (e. g., expansion, shearing stress, WSI, WAI) allowed to choose the most efficient model of fermentation pretreatment to obtain the best improvement of nutritional and functional features of the product.     

Physical and sensory characterization and consumer preference of corn and barley-fed beef

Steaks from corn-fed and barley-fed beef were characterized by a trained panel, which rated corn-fed beef higher (p<0.05) for tenderness attributes and overall flavor intensity. Canadian consumers preferred (p<0.01) cooked and raw steaks from barley-fed beef, while Mexican consumers showed no preference (p>0.05) for either type of finished beef. Japanese consumers showed a preference (p<0.05) for the appearance of raw barley-fed steaks but a preference for cooked corn-fed steaks (p<0.05). No differences (p>0.05) were observed for Warner-Bratzler shear, marbling scores, cooking losses or Hunter colorimeter values. There was a trend for higher concentrations (p<0.08) of the saturated fatty acids in the barley treatment, but no differences (p>0.10) in mono or polyunsaturated fatty acids.     

Textural and physicochemical predictors of sensory texture and sweetness of boiled plantain

Boiled pulp is a major form of consumption for plantain. We assessed instrumental (puncture test and texture profile analysis) and sensory texture attributes of 13 plantain cultivars, two cooking hybrids and one dessert banana at different stages of ripeness after cooking in boiling water. Firmness, chewiness, stickiness, mealiness, sweetness and moistness described sensory variability, which was greater between stages of ripeness than between types of cultivars. Firmness and chewiness were well-predicted by instrumental force and hardness (r² > 0.72), and by soluble solid and dry matter content (r² > 0.85). Complementary sensitivity analysis revealed that a pulp puncture force or a hardness of at least 2.1 N or of 0.3 N/mm² was needed before a difference in firmness or chewiness could be perceived; a Brix of 3.7 was required to ensure a detectable difference in sweetness. Rheological and biochemical predictors can be useful for breeders for high-throughput phenotyping.     

姜黄素的乳化和包埋及其应用研究进展

姜黄素是从姜科、天南星科中的一些植物的根茎中提取的一种化学成分,是植物界很稀少的具有二酮的色素。姜黄素作为我国允许使用的一种天然着色剂,具有一系列生物药理活性,但是其理化稳定性差、生物利用度低,往往需很大用量才能达到作用剂量,将其乳化包埋后不仅可以解决其溶解性的问题,还可以提高其生物利用率,应用前景十分广阔。该文通过总结国内外大量文献,阐述姜黄素的基本性质及其乳状液的基本性质和乳化包埋的方法,同时介绍姜黄素的创新应用,并对其发展前景作出展望。     

Properties and characterization of antioxidant and antiglycative activities for the multiple harvests of aquatic- and field-cultivated peanut leaves and stems

Peanut top parts of leaves and stems are feasible to be consumed as a vegetable. Peanut kernels of Tainan 9 were aquatic- and field-cultivated for 30 days and the top parts were harvested for three times at a 10-day interval. The highest total phenolics, epicatechin and caffeic acid contents in leaves were detected in the second harvest of aquatic-cultivation. In comparison, higher epicatechin and caffeic acid contents were observed in leaves of aquatic-cultivation than the field-cultivated leaves. The reducing powers, total equivalent antioxidant capacity and inhibitory activities against AGEs formation varied with a close dependence on total phenolics contents. Based on SDS–PAGE analysis, all harvested aquatic- and field-cultivated peanut leaves were effective in inhibition of albumin glycation. It is of merit to demonstrate that multiple harvests of the green top parts of peanuts bear potent antioxidant and antiglycative activities.     

论我国农产食品质量安全的政策措施

农产食品安全是当今世界人们所关注的焦点问题之一,国际贸易中也因此正在形成一道坚固的新型＂安全壁垒＂.随着社会经济和贸易的发展,我国农产食品质量安全问题显现的越来越突出,质量安全事件时有发生,到了非得引起足够重视的时候.本文分析了目前我国在农产食品安全的发展上与发达国家存在的差距,分析了在农产品生产、加工、销售等环节存在的安全隐患,以及我国在农产食品安全标准体系、检验检测体系、认证认可体系、管理体制和法律法规体系、安全技术储备等方面的不足,提出了应当加大对农业生产的科技投入力度,科学引导农产食品的生产和加工,同时积极寻求国际技术援助;建立行之有效的农产食品出口体制,对出口农产食品的加工厂实施有效的卫生注册登记制度和市场准入制度;建立培育行业协会等中介组织,完善我国农产食品出口的预警通报机制和快速反应机制,完善我国有关生态环境保护和农产食品安全卫生的标准体系和法律制度,加快进出口农产食品安全标准体系建设;整合国内认证资源、完善农产食品安全检测体系和认证体系等政策措施.