养乐多饮料中影响干酪乳杆菌代田株活菌数因素的研究

研究了乳饮料的发酵过程中影响乳酸菌高活菌数的因素。以干酪乳杆菌代田株为菌种,设定接种量、营养条件、培养温度为实验因素对乳酸菌发酵过程进行研究,以活乳酸菌数量为检测指标,确定最佳的发酵稳定的高活菌数乳饮料的工艺条件。结果表明,30℃的培养温度,发酵培养基奶粉的加入量为5%,发酵2d~4d后可获得稳定的109个/mL以上的高活菌数的乳饮料。     

The influence of certain factors on thickness loss after the hot gluing of cut lamellas into solid wood layered boards

An experimental laboratory investigation has been carried out into the hot gluing of solid wood layered boards made out of 5.3 mm thick solid-wood lamellas, the latter being produced by the lengthwise veneer cutting technique, the object of the research being to determine some of the reasons (humidity of wood before heating, temperature of wood before cutting into lamellas, and temperature and pressure during the gluing of boards) for the permanent thickness loss which occurs during gluing. Spruce wood (Picea abies (L.) Karst.) was used in the experimental tests. Before cutting into lamellas, this wood was classified into two humidity groups, and heated to three different temperatures. The dried lamellas were used, after suitable preparation, for the two outer layers, which were glued, together with a middle layer of sawn lamellas, by the hot gluing process. A total of 162 laboratory boards, of length 500 mm, width 475 mm and thickness from 24 to 25 mm, were hot glued, using melamin-urea-formaldehyde glue, at three different gluing temperatures and three different gluing pressures. Regression analysis of the measured results of thickness loss showed that the influence of the studied factors on thickness loss was linear, and that thickness loss depends the most on gluing pressure, followed by gluing temperature. It was also found that a higher wood humidity results in a slightly greater thickness loss than the wood’s temperature before cutting into lamellas.     

The influence of mechanical tenderization on the palatability of certain bovine muscles

Twelve different muscles or muscle groups were removed from both sides of 25 Canada AA beef carcasses. Muscles or muscle groups from alternate carcass sides were either mechanically tenderized or served as controls. Mechanical tenderization increased thaw-drip losses from the brisket approximately 1.25% and cooking losses from the blade eye by approximately 2.75%, but did not influence cooking times. Mechanical tenderization also improved initial and overall tenderness of the outside round, top sirloin, striploin, inside round and chuck tender. In addition initial tenderness of the sirloin tip eye and overall tenderness of the eye of the round were improved by mechanical tenderization. Moreover, connective issue in the top sirloin, striploin, and eye of the round was less perceptible after mechanical tenderization, but juiciness was decreased in the blade eye and top sirloin. Flavor intensity of the top sirloin and rib-eye was also reduced by mechanical tenderization. However, the desirability of the flavor of the inside round was improved by mechanical tenderization and the overall palatability of the inside round and eye of the round improved with mechanical tenderization. Mechanical tenderization decreased the proportion of inside round samples rated tough initially and overall from 52 to 20% and from 36 to 12% respectively. Mechanical tenderization also reduced the proportion of outside round samples perceived to contain a slight or greater amount of connective tissue from 36 to 12%. In addition, mechanical tenderization reduced the proportion of inside round samples with undesirable flavor from 16 to 0% and reduced the proportion of unpalatable rib-eye, inside round, and eye of the round samples from 12 to 0, 36 to 8 and 80 to 40%, respectively. Consequently, mechanical tenderization can be effectively utilized to reduce the variability and improve the tenderness and palatability of certain muscles, particularly hip muscles.     

The influence of certain metal ions on the visible spectra of food dyes

Summary. The visible absorption spectra of twenty-two food dyes have been plotted both in the free state and in the presence of added calcium, magnesium, aluminium, iron (II), iron (III), copper (II) and cobalt (II) ions at the pH values 3.0, 6.4, 7.4 and 12.5.
The frequencies of the absorption band maxima of the free dyes are briefly discussed in relation to colour and structure. While added metal ions do not, in general, have an appreciable effect on the spectrum of the dye, the transition metal ions studied frequently bring about a shift in the characteristic frequencies of the free-dye absorption maxima. Examples of where this effect is greatest are carmoisine in the presence of copper (II) at pH 6.4 and 7.4, and black PN in the presence of iron (II) at pH 12.5.
The possibility of dye complexes affecting iron metabolism is also briefly discussed.     

The influence of technical factors on differential cell count in milk

Differential cell count of milk is a traditional parameter for the evaluation of udder health. The literature shows great variation in differential cell counts of the milk of healthy mammary glands: macrophages range from 0% to 80%, lymphocytes from 1.5% to 79.5%, polymorphonuclear neutrophils from 3% to 95%, and epithelial cells from 1% to 19%. We conducted three studies to seek explanations for such variation. In the first, we evaluated the impact of polyethylene and glass sampling bottles. The aim of the second study was to compare the results of differential cell counts performed by three different technicians. The third study evaluated two methods of smear preparation. When polyethylene plastic bottles were used, the macrophage population was minimized but lymphocytes remained unaffected. This was shown by an exemplary flow cytometric analysis using four monoclonal antibodies against three lymphocyte surface structures. There were significant differences in the differential cell counts of 40 smears made by three technicians despite identical operating procedures. For the sediment smear, milk was centrifuged once and the sediment spread by eye on a glass slide. For the "coffee grinder" smear method, the sample was subjected to four centrifugations and then placed on a cover glass in order to spread the sediment using centrifugal force. The coffee grinder procedure led to a reduction of lymphocytes and an enrichment of polymorphonuclear neutrophils without affecting the macrophage population. Both methods made it possible to distinguish different udder health classes. It can be concluded that differential cell counts are a useful tool for comparing and monitoring udder health only if: samples are taken in a glass bottle; smears are prepared with the identical technique; and the differential cell counts are performed by a single person.     

尾叶桉制浆的生产实践

介绍了尾叶桉的纤维特征、化学组成,制浆工艺流程、设备选型、技术参数以及生产过程中遇到的问题与解决办法,并与马尾松浆进行了比较.     

烤烟烟叶DNA甲基化与气象因子的关系分析

为深入研究特色烟叶的形成与气象因子的关系,用灰色关联理论结合生产实际选出与烟叶DNA甲基化相关的平均最高温度、总日照时数、平均相对湿度和总降雨量等4个气象因子,并建立了DNA甲基化(因变量)与4个气象因子(自变量)之间修正的Logistic模型.单因子效应分析表明,平均最高温度、总日照时数和平均相对湿度与DNA甲基化水...     

蒸煮助剂DA2709用于进口桉木的蒸煮实践

通过工艺优化、设备改造、使用蒸煮助剂,漂白浆产量由22万t/a提高到29.5万t/a,蒸煮用碱量降低5.0%,未漂浆得率提高3.3%,漂后浆得率提高2.9%,TDS降低5.40%,在蒸煮卡伯值提高7.7%的情况下,氧脱后卡伯值、白度仍维持在目标范围内,ClO2消耗平均降低10.8%,Cl2消耗平均降低8.3%,总渣子量降低5.3%.     

影响低温火腿肉色泽的因素研究

色泽是衡量低温火腿肉品质的重要感官指标。通过试验研究确定确定影响低温火腿肉色泽的主要因素是肉的比例结构、杀菌温度、亚硝酸钠加入量、乙基麦芽酚是否加入及其加入量，其中一个因素发生变化，肉的色泽没有相应的改变。     

The influence of local factors on the prediction of fumonisin contamination in maize

BACKGROUND: Contamination by mycotoxins is a major concern to the maize industry in north‐east Italy where maize grain is often spoiled by Fusarium spp. In this work, fumonisins, deoxynivalenol and zearalenone were determined and an artificial neural network (ANN) model suitable for predicting mycotoxin contamination of maize at harvest time was developed. RESULTS: The occurrence of deoxynivalenol and zearalenone was very limited, while fumonisins concentration ranged from 163 and to 3663 µg kg^?1 in 2007, and from 333 to 11473 µg kg^?1 in 2008. Statistical data analysis of factors affecting fumonisins concentration revealed that irrigation, chemical treatment against the European corn borer and harvest date significantly affected the level of contamination (P < 0.05), although the relevance of the factors was different in 2007 and 2008. The neural network approach showed a significant correlation between ascertained values and predictions based on agronomic data. CONCLUSION: This is the first time that an artificial neural network has been used to predict fumonisin accumulation in maize: the prediction has been shown to have the potential for the development of a new approach for the rapid cataloging of grain lots. Copyright © 2012 Society of Chemical Industry     

影响低温火腿肉嫩度因素的研究

嫩度是衡量低温火腿肉品质的重要感官指标。通过试验研究确定影响低温火腿肉嫩度的主要因素是肉的选择及其比例结构、杀菌温度、是否加入磷酸盐、氯化钙、淀粉等,其中一个因素发生变化,肉的嫩度有相应的改变。     

温度对聚酯增强基PVC篷盖布蠕变应变性能的影响

分析了不同测试温度条件下,3种聚酯增强基PVC篷盖布试样加载24 h内的蠕变应变特性.结果表明,各试样经纬向的蠕变应变曲线基本相同,试样蠕变应变的大小受测试温度、加载时间和聚酯增强基布中衬经衬纬纱排列密度的影响.测试温度越高,试样的蠕变应变越大.同规格试样纬向的蠕变应变大于其经向.聚酯增强基PVC篷盖布试样经纬向的蠕变应变随增强基布中衬经衬纬纱排列密度的增加而增大.     

The influence of cow factors on the incidence of clinical mastitis in dairy cows

Many cow-specific risk factors for clinical mastitis (CM) are known. Other studies have analyzed these risk factors separately or only analyzed a limited number of risk factors simultaneously. The goal of this study was to determine the influence of cow factors on the incidence rate of CM (IRCM) with all cow factors in one multivariate model. Also, using a similar approach, the probability of whether a CM case is caused by gram-positive or gram-negative pathogens was calculated. Data were used from 274 Dutch dairy herds that recorded CM over an 18-mo period. The final dataset contained information on 28,137 lactations of 22,860 cows of different parities. In total 5,363 CM cases were recorded, but only 2,525 CM cases could be classified as gram-positive or gram-negative. The cow factors parity, lactation stage, season of the year, information on SCC from monthly test-day records, and CM history were included in the logistic regression analysis. Separate analyses were performed for heifers and multiparous cows in both the first month of lactation and from the second month of lactation onward. For investigating whether CM was caused by gram-positive or gram-negative pathogens, quarter position was included in the logistic regression analysis as well. The IRCM differed considerably among cows, ranging between 0.0002 and 0.0074 per cow-day at risk for specific cows depending on cow factors. In particular, previous CM cases, SCC in the previous month, and mean SCC in the previous lactation increased the IRCM in the current month of lactation. Results indicate that it is difficult to distinguish between gram-positive and gram-negative CM cases based on cow factors alone.     

影响酵母菌发酵的因素

在啤酒的生产过程中,酵母的接种纯度、发酵力和酵母的生存环境至关重要,直接影响到啤酒生产中发酵能否顺利进行,生产出的产品质量是否稳定。为此,文中对影响酵母发酵的因素进行了分析,并针对生产中的问题提出了解决的措施,可供同行们参考。     

利用正交实验和模糊评价改进香榧加工工艺

为提高香榧加工品品质,改进香榧加工工艺,以香榧为原料,在单因素试验基础上,通过对香榧加工工艺进行3因素3水平的正交实验设计(第1次炒制时间、浸泡液浓度、第二次炒制时间),并应用模糊评价法对香榧加工品进行感官评定,以模糊评定结果作为正交实验结果值,通过正交设计助手ⅡV3.1进行结果分析。研究结果表明,椒盐香榧加工工艺最佳工艺是:第1次炒制10 min,0.02%V E+2%盐水浸泡液,第2次炒制10 min,在此工艺条件下制得香榧的感官评定结果达到79.9分,验证实验结果证明,该方法用于优化香榧的加工工艺切实可行,为进一步提高香榧品品质提供了理论依据。     

桉木APMP制浆工艺及其优化

研究了按木APMP的木片挤碾、螯合前处理和化学预处理等最佳制浆工艺，并在此基础上探讨了按木APMP与蔗渣化机浆配抄胶印书刊纸的可能性。使用挤碾机处理桉木木片，以利于药液浸透，较大幅度地提高纸页的白度和强度，是本研究的创新之处。     

影响甘蓝泡菜中亚硝酸盐含量因素的研究

摘要：本文以甘蓝为主要原料，研究了在30℃条件下影响甘蓝泡菜中亚硝酸盐含量的几种主要因素．结果表明：采用纯接种技术，在发酵前期可有效降低亚硝酸盐的含量，其中以接种肠膜明串珠菌效果最佳；同时在发酵过程中添加适量蒜汁或姜汁，可明显地抑制甘蓝乳酸发酵中亚硝峰出现；且在发酵过程中，泡菜的pH值对亚硝酸盐含量也有较大的影响。在发酵成熟后，泡菜中的亚硝酸盐含量趋于稳定，且各种发酵方式对成熟泡菜中亚硝酸盐的含量基本无影响。     

The influence of extrinsic factors on the microbiological spoilage pattern of ground beef

Two hundred and thirty four samples of raw minced beef were subjected to storage at 0 and 7 degrees C over a period of 17 days. The samples were subjected to four different treatments where the controls (Treat 1) were aerobically packed. The vacuum-packed samples (Treats 2 and 3) differed only by the addition of 0.5% L-(+)-ascorbic acid to the Treat 3 samples. Treat 4 represented aerobically packed samples to which a commercial 'colour retainer' was added. The microbiological results showed clearly that temperature control around 0 degree C was the central element in achieving shelf life extension of raw minced beef. Vacuum packaging and additive treatments enhanced the effect of low storage temperatures. Identification of 128 psychrotrophic spoilage isolates revealed a predominance of Gram-negative bacteria (63%), most of which were classified as Pseudomonas spp. (72%), the rest being Enterobacteriaceae. Among Gram-positive isolates, lactobacilli and yeasts predominated (45% and 28%, respectively). Commonly observed oxygen relationships were not found in this study. Pseudomonads proliferated even in vacuum packaged samples throughout the entire storage period, whilst lactic acid bacteria were also found in high numbers in aerobically packaged samples. Identification of 71 isolates of lactic acid bacteria revealed a strong predominance of Lactobacillus saké (34%), followed by L. curvatus (23%), L. bavaricus (21%) and L. alimentarius (10%). Significant numbers of lactobacilli were isolated from samples in all treatment groups, including the aerobically packed categories.     

鲤鱼组织蛋白酶L活性的影响因素研究

主要研究了鲤鱼组织蛋白酶L活性的影响因素。结果表明,鲤鱼组织蛋白酶L具有较强的稳定性,在-20℃冻藏、20⁵0℃加热处理、不同酸性环境中均保留了一定程度的活性;鱼肉中组织蛋白酶L在漂洗工艺中并不能完全去除,漂洗后仍残存了45.65%活性。此外,鲤鱼组织蛋白酶L在豆科类蛋白、大米蛋白、鸡蛋清蛋白、马铃薯蛋白、茶多酚和大豆异黄酮等各种食品组分作用下,其活性发生明显的下降,且呈现良好的量效关系。