少孢根霉固态发酵β-葡萄糖酶关键单元优化研究

研究了黄豆芽液体培养基制备少孢根霉生产菌种的工艺条件，即100mL黄豆芽汁，3g麦芽糖，1％硫酸铵和0．4％尿素，用乳酸调节pH值为4．5，接种1．5g少孢根霉制剂，37℃振荡培养24h后再用大豆粉和马铃薯固态培养基，即大豆粉和马铃薯的比例为5：1，9％乳酸酸化（含乳糖0．2g／10g（干基）、硫酸铵0．2g／10g（干基），以少孢根霉作为发酵菌种，于30℃培养48h，发酵生产β-葡萄糖苷酶，其酶活达到716U／g。     

固定化乳酸菌发酵大豆酸乳研究

用1．2％的海藻酸钠与1．5％聚乙烯醇，分别加10mL乳酸菌（约10^10/mL）制备保加利亚杆菌固定化球（C）和嗜热链球菌固定化球（D），C：D最佳比为2：1，置待发酵大豆乳原料中前发酵培养20min，然后将含乳酸菌的大豆乳于40℃进行主发酵培养3h-4h，再置于8℃－10℃后发酵约12h即成酸豆乳。固定化乳酸菌球连续发酵40h，固定化球破损率低于30％。按4．0g/kg大豆加混合碱，在25℃浸泡7h-9h，热水磨浆后煮沸2min，可获满意脱腥豆浆。     

Fenton预处理提高聚乙烯醇可生化性

在退浆废水中，聚乙烯醇（PVA）是一种污染严重又难以生物降解的物质，采用Fenton法对其进行预处理，可明显地改善其生化性，研究表明，当溶液初始pH值为4．0，H2O2／Fe^2＋（摩尔浓度比）=10，H2O2／COD（质量浓度比）=1．5，反应温度为40℃，反应30min时Fenton预处理的效果最佳，COD去除率达到80％以上，BOD／COD值也由0．1左右增加到0．7．经过活性污泥法的处理，COD去除率由未经预处理时的2％提高到88％左右。     

稀碱浸渍对高粱麦芽微生物污染、毒性及糖化力的影响

浸渍过程中添加稀碱性物质可到达降低高粱麦芽中霉菌，大肠菌的数量，抑制毒素产生的预期目标单宁含量多的红色高粱品种NK283和PAN8546分别浸渍在0．1％，0．2％和0．3％的NaOH及0．1％，0．3％和0．5％的Ca（OH）2中。对浸渍溶液中的乳酸菌，酵母，霉菌进行好氧微生物平板菌落记数，从而对高粱麦芽的某些真菌毒素（黄曲霉毒素，腐马素毒素，脱氧瓜萎镰茼醇，玉米烯酮），细胞毒素以及糖化力（DP）进行评估。高粱NK283浸渍在0．1％Ca（OH）2中，使得DP从10．5增加到16SDU／g。然而，对麦芽微生物数量却没有有效的降低。浸渍在稀浓度的NaOH中可减少麦芽中的微生物菌落数量，所有浸溃在0．2％NaOH溶液中的麦芽品种，其霉菌和大肠菌的含量大约会降低3．5和2．0cfu／g，同时，某些种类的霉菌数量也会大大下降，甚至检测不到。在0．2％NaOH中浸溃的麦芽，NK283的糖化力从16．2增加到26．9SDU／g，同样的结果出现在PAN8546中。而真菌毒素和细胞毒素在其样品中检测不到。在高粱制麦过程中添加0．2％食品级的NaOH可作为一种有效地控制细菌和真菌污染的方法。     

高产纤维素酶青霉菌的筛选和及产酶条件的研究

本文从稻田土壤中分离到—株产纤维酶活力高的X-5菌株，经形态特征及生理生化特征初步鉴定为半知菌亚门，丝孢纲，丝孢目，丛梗孢科，青霉属（Penicillium）。对青霉菌X-5菌株进行发酵培养条件的研究结果表明，以5．0％稻草粉为碳源，3．0％豆饼粉为氮源，装液量为60ml，接种量为5．0％，培养温度为26～28℃，初始pH4．5-6．0，培养120h，产酶活力最高，CMC酶活为75．72IU／ml，FP酶活为6．68IU／ml.     

RP—HPLC法测定黄芩苷和黄芩素的含量

目的用反向高效液相（RP—HPLC）法测定滇黄芩和黄芩中黄芩苷和黄芩素的含量。方法乙腈（含1．0％甲酸）-1．0％甲酸溶液为流动相，梯度洗脱，流速为1．0mL／min，检测波长274nm，柱温30℃。结果在精密度，重现性，稳定性实验中，保留时间和峰面积的RSD均小于2％；加标回收率分别为100．7％和100．5％，RSD为1．78％和1．85％；黄芩苷在0．102-2．04μg之间，黄芩素在0．72-14．40μg之间呈良好的线性关系，r=0．9999。结论此实验方法简便、准确、重复性好。     

微生物催化制备功能性油脂——共轭亚油酸的研究

从酸菜中分离出的一株植物乳杆菌Lactobacillus plantarum诱导培养，在氮气保护下利用休止细胞催化制备共轭亚油酸。0．1M磷酸钠缓冲液、pH值7．0、亚油酸浓度2％（w／v）、细胞浓度20％（w／v）、30℃。反应64h，共轭亚油酸产量最高。c9，t11／t9，c11—CLA异构体在产物脂肪酸中的比例为30％。     

高效液相色谱法测定蜜饯中食用合成色素

建立了蜜饯中食用合成色素（柠檬黄、苋菜红、胭脂红、日落黄、亮蓝）的高效液相色谱测定方法，采用C18（4.6mm×200mm，5μm）色谱柱，甲醇和乙酸铵为流动相，流速为1．0mL/min，柱温30℃，梯度洗脱程序为：甲醇＋0．02mol／L乙酸铵，6％～40％甲醇，2．8％／min；40％～60％醇，2．5％／min；60％甲醇，3min；6％甲醇，7min；检测波长：0min～5．5min，430nm；5．51min～8．0min，520nm；8．01min-10．0min，510nm；10．01min-13min，480nm；13．01min-20min，600nm。确定了蜜饯中合成色素的前处理方法。本方法具有灵敏度高，干扰少，色素回收率高的优点。     

乙醇和山梨酸钾对鲜食葡萄采后灰霉菌的抑制作用

灰葡萄孢接触10％和20％的乙醇30s后接种在PDA培养基上的萌发率分别是87％和56％，而对照是99％。用山梨酸钾进行同样处理，灰葡萄孢萌发率分别是84％和68％。用10％和20％乙醇加0．5％和1．0％山梨酸钾协同处理能显著提高对灰葡萄孢的抑制效果。20％乙醇和0．5％山梨酸钾处理后孢子萌发率是9．7％。接种灰葡萄孢的散粒“火焰无核”葡萄用水、10％和20％乙醇、0．5％和1．0％山梨酸钾单独处理后灰霉发生率分别为55．2％、42．1％、31．0％、37．7％和24、4％，而10％和20％乙醇加0．5％和1、0％山梨酸钾协同处理腐烂率都降到10％以下。接种灰葡萄孢的“汤姆森无核”葡萄串用10％和20％乙醇、0．5％和1．0％山梨酸钾单独及协同处理30s，在1℃下贮藏30d后发现20％乙醇加0．5％和1．0％山梨酸钾协同处理对灰葡萄孢的抑制效果与使用S0：药垫的效果相当，并且对葡萄无任何伤害。     

酵母菌产甘油激酶的发酵条件优化

筛选得到产甘油激酶（GK，EC2、7．1．30）德巴利酵母菌，对其发酵条件进行了优化，确定其最适培养基配方为葡萄糖0．1％，KCl 0．18％，酵母膏0．3％，柠檬酸0．6％，甘油0．5％。最适培养条件为接种量6％，装液量为120mL／250mL，160r／min、31℃培养25h。在最适培养基及最适条件下，甘油激酶的酶活力可达1.19U／mg。     

A practical trial of pyrethrins-in-oil surface sprays for the protection of bagged grain against infestation by Cadra cautella (Wlk.) (Lepidoptera, Phycitidae) in Kenya

Two formulations of synergized pyrethrins in technical white oil were tested as monthly protective sprays on stacks of fumigated bagged wheat, primarily against Cadra cautella (Wlk.) but also against Sitophilus oryzae (L) and Tribolium castaneum (Hbst.), under warm-temperate storage conditions in up-country Kenya. The formulations were: 0·4% pyrethrins with 2·0% piperonyl butoxide, applied at 50 ml/m², and 0·4% pyrethrins with 0·4% piperonyl butoxide at 20 ml/m².

Results were assessed by recording infestation in samples taken from each stack after 18 weeks storage and five spray applications.

Both treatments gave reasonably good protection against C. cautella but were not satisfactory against S. oryzae or T. castaneum. There was no evidence of any taint in bread made from the treated grain, but the higher application rate caused excessive staining of the bags.

It is concluded that satisfactory control of reinfestation by C. cautella can be expected in practice using 0·4% pyrethrins in oil with only a minimal quantity of added piperonyl butoxide, and that 20 ml/m² is a suitable rate for application to bagged produce.     

The microbiological profile of chilled and frozen chicken

To determine the effect of different refrigeration and freezer temperatures on the microbiological profile of chicken, 50 commercially processed broiler chickens were each split in half on the day of processing. Equal groups were held at 4, 0, -4, -12, and -18 degrees C (40, 32, 26, 10, and 0 degrees F), respectively for 7 days. One half of each group was then transferred to a 0 degrees F holding chamber for an additional 7 days. Carcass halves were rinse sampled with 100 ml of phosphate-buffered saline and the diluent sampled for mesophilic, psychrotropic, coliform, and salmonellae counts after the initial 7 days at different temperatures and after 7 additional days at -18 degrees C. Ten carcass halves were sampled on the day of processing to give baseline counts. Mesophilic bacteria counts/ml were about log 4.6 on day 0, increased by 2 log after 7 days on carcasses held at 4 degrees C, and were unchanged at all other storage temperatures. Psychrotropic counts/ml were about log 3.6 on day 0 and increased during the initial 7 days by about 3.9, 1.9, and 1.4 logs, respectively on carcasses held at 4, 0, and -4 degrees C and had less than 1 log increase at -12 and -18 degrees C. Coliform counts were about log 2.2/ml on day 0 and had declined to about log 1.5/ml or less by day 7 for all storage temperatures. Escherichia coli counts/ml were about log 2 on day 0 and were reduced about 1 log or more at other storage days. Salmonellae counts were about log 1.5 on salmonellae-positive carcasses and did not change appreciably at any storage temperature. No counts for any organism significantly changed after placement at -18 degrees C.     

金针菇FV_(8812)菌株深层发酵工艺的研究

金针菇FV_8812(Flammnlina Velutipes)菌株是我们从国内外收集到的25株菌株中,经筛选获得的一株适合深层发酵的高产优质菌株。本文报道了该菌株的适宜发酵培养基、摇瓶发酵条件及50升发酵罐的扩大试验结果。结果表明,其适宜发酵培养基的组成为5.0％玉米粉、3.0麸皮、0.1％KH_2PO_4、0.05％MgSO_4·7H_2O、10μg/100ml VB_1、50μg/100ml VB_2;适宜的摇瓶发酵条件为:培养温度20～25℃培养基起始pH6.0～7.0,摇瓶装量500ml,装100～160ml,种子培养时间3～4天,接种量10～15％,摇瓶转速120～200rpm添加消泡油不少于0.1％为宜;经50升发酵罐扩大试验,菌体干收率3.94％(W/V),达到了工厂化发酵生产食用菌菌丝体的要求,因而具有工业投产意义。     

Fertility of lactating dairy cows treated with Ovsynch after presynchronization injections of PGF2 alpha and GnRH

Synchronization of ovulation (Ovsynch) using GnRH and PGF2 alpha allows control of follicle growth, corpus luteum regression, and ovulation, but resulting pregnancy rates vary. This study examined whether presynchronization to allow initiation of Ovsynch during diestrus would improve pregnancy rates at timed artificial insemination (AI). Lactating dairy cows (n = 427), 69 to 75 d postpartum, were randomly assigned to two groups by parity. Control cows received Ovsynch (GnRH, d 0; PGF2 alpha, d 7; GnRH, d 9; timed AI 16 h after second GnRH). Treated cows received presynchronization injections of PGF2 alpha and GnRH, 10 and 7 d, respectively, before starting Ovsynch. Pregnancy diagnoses were performed 36 d after AI. Progesterone (P4) concentrations from a subset of cows (n = 84) were determined in serum samples collected on d 0, 3, and 7 of Ovsynch. Presynchronization increased the percentages of cows with > or = 1 ng/ml serum P4 compared with control cows at first injection of GnRH (d 0; 93 vs. 56%) and on d 3 (90.7 vs. 51.2%) during Ovsynch. On day of PGF2 alpha, d 7 during Ovsynch, percentages of cows with > or = 1 ng/ml serum P4 were similar (95.3%, treated vs. 82.9%, control) but more treated cows had > or = 2 ng/ml serum P4 (95.3 vs. 63.4%). However, pregnancy to timed AI was similar between treated (41.5%) and control cows (38.3%). Cows with above-average milk production had greater pregnancy rate (45.8 vs. 33.8%) compared with lower producing cows. Although presynchrony increased the proportion of cows with luteal function at onset of Ovsynch, pregnancy rate to timed AI was not improved. Cows with above-average milk production had greater fertility at timed AI than herdmates with lower milk production.     

胆红素氧化酶产生菌的选育及发酵工艺条件的研究

对胆红素氧化酶产生菌的菌和选育进行了研究。以科研室保藏菌种Mv9201为出发菌株，通过紫外线、硫酸二乙酯单独处理和复合诱变，从353株突变株中筛选出一株高产菌株MyrotheciumverrucariaMv9352，并对其产酶条件进行了研究。以20％的土豆汁（含0．25％的葡萄糖和蛋白胨）为发酵培养基，初始pH6～7，摇床转速为140～160r／min，24～26℃培养96h，酶活力可达4．0～4．5u／ml，比出发株的产酶能力提高近4．5倍。     

高效液相色谱测定浓缩沙棘汁中的维生素C

提出了一种高效液相色谱法测定浓缩沙棘汁中的维生素C的方法,方便简便、快速、准确。对样品进行测定,变异系数为0.41％,加标回收试验,回收率为99.7％～101.2％。     

Inactivation of Escherichia coli O157: H7 and Listeria monocytogenes by PR-26, a synthetic antibacterial peptide.

This study reports the antibacterial effect of PR-26, a synthetic peptide derived from the first 26 amino acid sequence of PR-39, an antimicrobial peptide isolated from porcine neutrophils. A three-strain mixture of Escherichia coli O157:H7 or Listeria monocytogenes of approximately 10(8) CFU was inoculated to a final concentration of 10(7) CFU/ml in 1% peptone water (pH 7.0), containing 50 or 75 microg/ml of PR-26, and incubated at 37 degrees C for 0, 6, 12, and 24 h; at 24 degrees C for 0, 12, 24, and 36 h; or at 10 or 4 degrees C for 0, 24, 72, and 120 h. Control samples included 1% peptone water inoculated with each pathogen mixture but containing no PR-26. The surviving population of each pathogen at each sampling time was determined by plating on tryptic soy agar with incubation at 37 degrees C for 24 h. At 37 degrees C, PR-26 decreased E. coli O157:H7 and L. monocytogenes populations by >5.0 log CFU/ml at 12 h, with complete inactivation at 24 h. At 24 degrees C, PR-26 reduced E. coli O157:H7 and L. monocytogenes by approximately 3.5, 4.0, and 4.5 log CFU/ml at the end of 12-, 24-, and 36-h incubations, respectively. At 4 and 10 degrees C, the inhibitory effect of PR-26 on E. coli O157:H7 and L. monocytogenes was significantly lower (P < 0.05) than that at 37 and 24 degrees C: a 2- to 3-log CFU/ml reduction was observed at 120-h incubation. Results indicate that PR-26 could potentially be used as an antimicrobial agent, but applications in appropriate foods need to be validated.     

Steroidogenic responses of pig corpora lutea to insulin-like growth factor I (IGF-I) throughout the oestrous cycle

This study was designed to investigate the roles of insulin-like growth factor I (IGF-I), IGF-type I receptor (IGF-IR) and IGF-binding proteins (IGFBPs) in regulating progesterone secretion by pig corpora lutea during the oestrous cycle, and the signal transduction pathways involved in mediating the steroidogenic actions of IGF-I. Corpora lutea were collected on days 4, 7, 10, 13 and 15 or 16 of the oestrous cycle, enzyme dissociated and the luteal cells were cultured for 24 h in Medium 199 with IGF-I (0-100 ng ml(-1)), long R(3)-IGF-I (0-100 ng ml(-1)), anti-IGF-I (Sm 1.2B; 0-10 microg ml(-1)), anti-IGF-IR (alphaIR3; 0-2 microg ml(-1)), or IGF-I signal transduction pathway inhibitors (phosphatidylinositol (PI)-3-kinase: 100 nmol Wortmannin l(-1) and 10 micromol LY 294002 l(-1); MAP kinase: 50 micromol PD 98059 l(-1)) to investigate their effects on IGF-I (100 ng ml(-1)) stimulated progesterone secretion. Pig luteal cells displayed dose-dependent responses to IGF-I and long R(3)-IGF-I on days 4 and 7 of the oestrous cycle, but not on days 10-16. There was no difference in the ED(50) or V(max) (maximal response) values between IGF-I and long R(3)-IGF-I. Neither anti-IGF-I nor anti-IGF-IR had significant effects on progesterone secretion, at any dose or day. Wortmannin and LY 294002 blocked IGF-I stimulated progesterone secretion, but PD 98059 was without effect. Finally, IGF-I (6 microg) infused into the ovary on day 7 in vivo significantly increased progesterone secretion within 45 min of infusion. The conclusions of this study are: (1) IGF-I has steroidogenic actions only on 'young' (days 4-7) pig corpora lutea; (2) endogenous IGF-I and IGFBP are insufficient to modulate progesterone secretion in vitro; and (3) the steroidogenic actions of IGF-I are mediated via PI-3-kinase.     

Survival and growth characteristics of Escherichia coli O157:H7 in pasteurized and unpasteurized Cheddar cheese whey

The objective of this study was to determine the survival and growth characteristics of Escherichia coli O157:H7 in whey. A five-strain mixture of E. coli O157:H7 was inoculated into 100 ml of fresh, pasteurized or unpasteurized Cheddar cheese whey (pH 5.5) at 10(5) or 10(2) CFU/ml, and stored at 4, 10 or 15 degrees C. The population of E. coli O157:H7 (on Sorbitol MacConkey agar supplemented with 0.1% 4-methylumbelliferyl-beta-D-glucuronide) and lactic acid bacteria (on All Purpose Tween agar) were determined on days 0, 1, 4, 7, 14, 21 and 28. At all storage temperatures, survival of E. coli O157:H7 was significantly higher (P<0.01) in the pasteurized whey compared to that in the unpasteurized samples. At 10 and 15 degrees C, E. coli O157:H7 in pasteurized whey significantly (P<0.05) increased during the first week of storage, followed by a decrease thereafter. However at the same temperatures, E. coli O157:H7 exhibited a steady decline in the unpasteurized samples from day 0. At 4 degrees C, E. coli O157:H7 did not grow in pasteurized and unpasteurized whey; however, the pathogen persisted longer in pasteurized samples. At all the three storage temperatures, E. coli O157:H7 survived up to day 21 in the pasteurized and unpasteurized whey. The initial load of lactic acid bacteria in the unpasteurized whey samples was approximately 7.0 log10 CFU/ml and, by day 28, greater than 3.0 log10 CFU/ml of lactic acid bacteria survived in unpasteurized whey at all temperatures, with the highest counts recovered at 4 degrees C. Results indicate the potential risk of persistence of E. coli O157:H7 in whey in the event of contamination with this pathogen.     

比光谱导数法同时测定食品中苯甲酸和糖精钠的含量

苯甲酸和糖精钠的吸收光谱重叠严重 ,本文建立了用比光谱导数法同时测定食品中两者含量的方法。结果表明 ,在不需要进行分离和掩蔽的条件下 ,可直接测定苯甲酸和糖精钠的含量 ,采用 2 4 5nm和 2 55nm分别作为两者的测量波长 ,其浓度分别在 0～ 90 μg/mL和0～ 10 0 μg/mL之内符合线性关系 ,回归的相关系数r均达 0 999以上。 5种食品中的苯甲酸和糖精钠含量测定的回收率分别为 97 7%～ 10 0 2 %和 10 1 2 %～ 10 4 4 % ,精密度 (测定 5次 )分别为 0 8%～ 4 9%和 0 9%～ 3 7%。此外 ,本文还讨论了波长、共存物、求导间隔等影响测定的因素 ,优化了测量条件。