富硒产朊假丝酵母的制备条件研究

研究了环境条件对产朊假丝酵母细胞生长和富硒能力的影响,在单因素实验的基础上进行正交试验,获得了较优的产朊假丝酵母生物转化无机硒为有机硒的环境条件组合:发酵培养基中初始亚硒酸钠浓度10 mg/L,摇床转速200 r/min,装液量40 ml/500 ml,温度27℃,初始pH值6.0.在此条件下,酵母生物量达到11 g/L,最终硒有机转化率为90.2%.     

固态发酵复方中药生产新型鱼类药物的研究

通过单因素试验和正交试验的方法,以纤维素酶活力为指标,黑曲霉、枯草芽孢杆菌和产朊假丝酵母作为发酵菌种,探讨多菌种混合发酵复方中药的最佳工艺条件,以及发酵复方中药对澎泽鲫幼鱼生长及免疫性能的影响。结果表明：复合菌种固态发酵中药的最佳工艺参数为发酵时间84 h,好氧厌氧时间比2︰1,初始含水量65%,发酵温度32℃,纤维素酶活力达到42.37 U/g;饲喂添加量0.3%的复方中药饲料后,澎泽鲫幼鱼体重增长率较未添加复方中药相比提高了16.63%,饵料系数降低了3.31%,复方中药经发酵后体重增加率相比未发酵中药提高了11.66%,饵料系数降低了4%;饲喂60 d后,发酵复方中药组血清超氧化物歧化酶、溶菌酶和丙二醛含量相比对照组差异显著。     

发酵饲料对黄河鲤生长、非特异性免疫功能的影响

研究枯草芽胞杆菌、产朊假丝酵母固态发酵对豆粕、玉米粉、小麦麸混合原料营养成分改善和发酵饲料对黄河鲤生长性能和非特异性免疫功能的影响。结果表明:混合原料固态发酵后显著提高了粗蛋白质含量,显著降低了粗脂肪、粗纤维和粗灰分含量。与普通商品饲料组比,枯草芽胞杆菌和产朊假丝酵母发酵饲料组黄河鲤生长性能提高显著,溶菌酶、超氧歧化酶和过氧化氢酶活性增强,产朊假丝酵母发酵饲料组增效更为显著。说明混合原料经固态发酵后可改善其营养特性,提高其利用率,增强黄河鲤抗氧化能力。     

棉酚降解酵母的筛选及其在棉粕发酵中的应用

棉粕中存在的游离棉酚是限制其作为优质蛋白饲料应用的主要因素。采用含有0.3%游离棉酚的液体培养基来富集并分离获得酵母,通过考察酵母在以棉酚为唯一碳源培养基上的生长情况以及在棉粕固态发酵中棉酚的降解情况,获得了一株高效降解棉酚的产朊假丝酵母TM-2。棉粕经产朊假丝酵母TM-2发酵后,游离棉酚含量从578 mg/kg降低至128 mg/kg,粗蛋白含量从46.5%提高到53.3%,酸溶蛋白含量从4.4%提高至12.4%,抗营养因子棉籽糖含量从8.9%降低至0.8%,表明产朊假丝酵母TM-2显著改善棉粕的饲用品质。     

两阶段pH控制方式提高富硒产朊假丝酵母的性能

为了提高富硒产朊假丝酵母的性能,本文在摇瓶培养和分批培养的基础上,考察了不同pH控制方式对流加培养条件下富硒产朊假丝酵母细胞生长、谷胱甘肽（GSH）合成和有机硒转化的影响,结果发现：在12 h将pH从3.5切换至5.5（pH 3.5→5.5）的两阶段pH控制方式最有利于富硒产朊假丝酵母胞内GSH和有机硒含量的提高。在pH 3.5→5.5条件下,富硒产朊假丝酵母胞内GSH含量、有机硒含量和有机硒转化率分别达到最大值13.09 mg/g、1.88 mg/g和94.69%。通过对酵母胞内GSH合成关键酶活性、氧化还原酶活性和能量代谢物质ATP水平进行测定,发现pH 3.5→5.5两阶段pH控制方式提高了富硒酵母胞内过氧化氢酶活性,降低了丙二醛含量,为酵母进行有机硒富集与转化以及GSH合成与积累提供了合适的氧化还原环境,并最终提高了富硒酵母的性能。     

固态发酵复方中药生产新型鱼类药物的研究

通过单因素试验和正交试验的方法,以纤维素酶活力为指标,黑曲霉、枯草芽孢杆菌和产朊假丝酵母作为发酵菌种,探讨多菌种混合发酵复方中药的最佳工艺条件,以及发酵复方中药对澎泽鲫幼鱼生长及免疫性能的影响.结果表明:复合菌种固态发酵中药的最佳工艺参数为发酵时间84 h,好氧厌氧时间比2∶1,初始含水量65％,发酵温度32℃,纤维素酶活力达到42.37 U/g;饲喂添加量0.3％的复方中药饲料后,澎泽鲫幼鱼体重增长率较未添加复方中药相比提高了16.63％,饵料系数降低了3.31％,复方中药经发酵后体重增加率相比未发酵中药提高了11.66％,饵料系数降低了4％;饲喂60 d后,发酵复方中药组血清超氧化物歧化酶、溶菌酶和丙二醛含量相比对照组差异显著.     

响应面法优化玉米浸液蛋白提取工艺及单细胞蛋白发酵的研究

探索了用等电点法提取玉米浸液中蛋白质的方法,并利用提取粗蛋白后的上清液生产单细胞蛋白。利用单因素实验分析了pH、温度、时间对蛋白提取的影响,通过响应面法确定等电点提取蛋白的最佳工艺,并研究了用酿酒酵母、产朊假丝酵母发酵离心上清液生产单细胞蛋白的条件。结果表明:等电点法提取粗蛋白的优化条件为:pH7.6、提取温度26.4 ℃、提取时间20 min,提取率为77.5%。以提取粗蛋白后的上清液生产单细胞蛋白,产朊假丝酵母优于酿酒酵母,当上清液中干物质浓度为8%、pH为5.5时,产朊假丝酵母发酵得到的菌落数达到1.6×109 CFU/mL。     

微生物降解菜籽粕中抗营养因子的研究

为降低菜籽粕中的植酸和粗纤维素含量,改善菜籽粕的品质,同时提高粗蛋白质含量,探讨了微生物对菜籽粕中抗营养因子的降解作用。结果表明:白地霉、产朊假丝酵母、黑曲霉和热带假丝酵母四菌种组合发酵能较好地提高菜籽粕作为饲料蛋白的品质,此时其粗蛋白质含量和植酸、粗纤维素降解率分别为46.9%、43.9%和9.8%。     

混菌发酵提高甘薯渣饲用价值的研究

对选育的扣囊拟内孢霉K991株、产朊假丝酵母C986株和绿色木霉T995株混合发酵甘薯渣生产的单细胞蛋白产品的饲用价值进行了研究。发酵产品的粗蛋白含量由发酵前8%提高到 2 6 9% ,纤维素降解了 36 16 % ,产品富含酵母活细胞和消化酶。替代 2 0 %饲喂猪试验表明 :产品适口性好 ,能降低料肉比 ,促进生长 ,具有较好的应用前景     

休哈塔假丝酵母发酵木糖生产乙醇的研究

木糖发酵是木质纤维素发酵的关键,休哈塔假丝酵母是自然界木糖发酵性能较好的天然酵母之一.研究了装液量、转速、木糖浓度、有机氮源等条件对休哈塔假丝酵母CICC 1766发酵木糖生产乙醇的影响,探讨休哈塔假丝酵母的乙醇耐受能力.结果表明,休哈塔假丝酵母对酒精的耐受能力达3%vol.在28℃,初始pH值5.0,160 r/min,250 mL三角瓶装液量150 mL,木糖浓度60 g/L,玉米浆0.5%(v/v),含尿素0.024%的条件下,休哈塔假丝酵母发酵木糖能产乙醇20.52 g/L,得率达到理论值的74.5%.     

胍基乙酸对育肥猪肉品质和抗氧化能力的影响

本试验旨在研究日粮添加不同浓度胍基乙酸（GAA）对育肥猪生长性能、肉品质和抗氧化能力的影响。140头健康的体重相近的育肥猪,随机分为4个处理,分别饲喂在基础日粮中添加0（对照组）、300、500和700 mg/kg的GAA,饲养期为35天。饲养过程中记录体重和采食量,屠宰时采集背最长肌和血浆样品用于肉品质和抗氧化指标分析。日粮添加GAA对育肥猪日采食量、日增重均有提高的趋势,对料重比也有降低的趋势（P>0.05）,显著降低平均背膘厚（P<0.05）;添加GAA可以显著提高育肥猪背最长肌宰后45 min的pH值,降低滴水损失、蒸煮损失和剪切力值（P<0.05）,对肉色影响不显著（P>0.05）;添加GAA显著提高血浆中谷胱甘肽过氧化物酶活性和总抗氧化能力,降低丙二醛含量（P<0.05）;添加GAA显著提高背最长肌中超氧化物歧化酶活性和总抗氧化能力,降低丙二醛和羰基含量（P<0.05）。育肥猪日粮中添加GAA可以改善背最长肌肉品质,增强机体的抗氧化能力。     

宰前短期饮水中添加VC对育肥猪肉品质的影响

试验考察宰前48 h饮水中添加VC对育肥猪血液指标、肉品质的影响.结果表明:宰前饮水短期添加VC对育肥猪胴体品质无影响;与对照组相比,添加VC 500和1 000 mg/L组血浆VC含量提高(P＜0.05),肉的亮度L*24h降低(P＜0.05);添加500 mg/L组肉的红度(α*24h)增加(P＜0.05).添加V...     

放养鸡肌肉品质和产肉性能分析

本试验旨在研究放养鸡肌肉品质和产肉性能。随机选取12周龄健康的放养铁脚麻母鸡10只,同时选取健康的笼养铁脚麻母鸡10只作为对照组,屠宰和产肉性能按"家禽生产性能名词术语和度量统计方法"中规定的方法进行,取胸肌和腿肌进行肉品质分析,主要分析蒸煮损失、p H、肉红度(a^*)、黄度(b^*)、亮度(L^*)、电导率(EC)、肌肉中脂肪和蛋白质、腹脂率及产肉性能等指标。结果表明,放养鸡胸肌的蒸煮损失、p H45 min、p H24 h、b^*45 min、蛋白质、脂肪、EC24 h分别为23.36%、5.65、5.65、17.67、83.16%、3.89%、6.80 m S/cm;腿肌的蒸煮损失、p H45 min、p H24 h、b^*45 min、蛋白质、脂肪、EC24 h分别为24.21%、5.88、5.84、16.80、72.81%、13.37%、5.00 m S/cm。放养鸡腹脂率、屠宰率、全净膛率、胸肌率、腿肌率分别为3.31%、91.43%、64.90%、22.76%、23.13%。与笼养鸡相比,放养降低了肉鸡胸肌蛋白质和腿肌p H,提高了屠宰后45 min胸肌和腿肌的a^*和b^*。放养鸡具有较好的肉色、新鲜度、产肉性能,且放养鸡肌肉具有低脂等特点。     

Strategic finishing feeding as a tool in the control of pork quality

A standard diet and two finishing feeding strategies known to reduce muscle glycogen stores were investigated in combination with exercise immediately prior to slaughter in pigs. The objective was to determine the influence of muscle glycogen at slaughter on temperature and pH in post-mortem muscle, the colour, drip loss and Warner–Bratzler shear force of the meat. The muscle glycogen stores were reduced by strategic finishing feeding. In general, pH_{45 min} was higher in muscles from strategically fed pigs compared with control pigs. Exercise also resulted in higher pH_{45 min} in control pigs compared to non-exercised control pigs, while the opposite was seen in muscles from strategically fed pigs. Exercise resulted in higher muscle temperatures in the carcasses irrespective of feeding strategy. pH_{24 h} were higher in M. biceps femoris and M. semimembranosus from exercised, strategically fed pigs compared with the corresponding controls. In contrast, irrespective of feeding strategy no difference in pH_{24 h} was registered in the meat of non-exercised pigs. Drip loss was lower in meat of strategically fed pigs compared with meat of control pigs. Moreover the drip loss was lowest in the meat of non-exercised pigs. The present study shows that strategic finishing feeding has high potential for the control of pork quality.     

多菌种分步固态发酵果渣生产菌体蛋白饲料的工艺优化

实验研究了多菌种分步固态发酵果渣生产菌体蛋白饲料的工艺条件,以果渣为主要原料,麸皮、豆粕、谷糠等为辅料,通过对多菌种(黑曲霉、产朊假丝酵母、热带假丝酵母和酿酒酵母)接种及培养方法、菌液的接种量、发酵的最佳温度、共发酵时间、固液比及物料酸碱度因素的优化研究,获得了优化后的多菌种分步固态发酵果渣生产菌体蛋白饲料生产工艺。通过单因素试验及正交试验,确定最佳发酵条件为固液比60%,初始pH5.5,温度30℃,黑曲霉的接种量为7.50%,复合酵母液的接种量为10%,黑曲霉在发酵初期接入,复合酵母液在发酵24h后接入,共培养时间为72h。在最佳菌种配比和发酵条件下,发酵终产物的粗蛋白质含量从4.97%增加至27.60%,增长了22.63个百分点,达到优质蛋白饲料标准。     

pH值对屠宰肉品质的影响

介绍了pH值的概念、pH值在家畜屠宰过程中的作用、pH值对内制品品质的影响.论述了pH值对内及肉制品产品加工的特性,通过控制加工过程中产品的pH值来保证产品质量.     

The effect of food deprivation prior to slaughter on performance, behaviour and meat quality

The effects of repeated food deprivation, prior to slaughter, on performance, feeding behaviour and meat quality of pigs was examined. Three experimental treatments were compared. In treatment 1 pigs had ad libitum access to feed up to the point of loading on the day of slaughter. Treatment 2 involved a 12-h fast prior to slaughter and treatment 3 involved a 20-h fast prior to slaughter. Pigs were slaughtered on a weight basis therefore each pen was emptied over a period of weeks. This meant some pigs experienced repeated food deprivation. The feeding pattern of pigs which were deprived of food for 12 h was very similar to that observed before feed restriction. Pigs which were deprived of food for 20 h spent significantly more time at the feeder post fasting. This was particularly marked during the first 2–3 h when access to feed was restored. Feed deprivation for 12 h prior to slaughter did not adversely affect performance, carcass weight, meat quality or welfare in the present study. Fasting for 20 h reduced carcass weight by 1 kg, which was not statistically significant but could result in financial losses related to carcass weight. The negative effects on meat quality, of repeated feed deprivation, resulted from slower growth rates rather than feed deprivation per se.     

Influence of Pre-Slaughter Process on Pork Quality: An Overview

Handling practices prior to slaughter have significant influence in the stress level and animal welfare of pigs, and consequently, in the final meat quality. This paper reviews current knowledge about ante mortem factors (fasting period, farm handling, mixing, loading, unloading, transport, lairage conditions, and driving to the stunner) related to the live animal that influence pork quality with special emphasis on technological quality attributes. The development in slaughter technologies and their practical applications in pig slaughterhouses are described. In spite of genetic effects and slaughter techniques, poor pre-slaughter operations lead frequently to an increase of physiological and physical stress in pigs. Ante mortem factors, such as lairage time or moving pigs into the slaughter rooms, and inadequate design of slaughterhouse facilities have an important effect on pig stress, affecting meat quality after slaughter. Some recommendations to guarantee animal welfare and obtain the best meat quality are reviewed.     

Effect of Conjugated Linoleic Acids in Pig Nutrition on Quality of Meat

Relationships among conjugated linoleic acid (CLA) in pig nutrition and carcass quality parameters (hot carcass weight, carcass yield and meatiness) and meat quality parameters (initial and pH value after 24, 48 and 72 h, temperature, drip loss, sensory color and marbling) were determined in pigs (crossbreeds Yorkshire x Landrace). Commercial CLA preparation containing 60% CLA isomers was included in the diet. No significant differences in performance parameters were found between pigs fed with CLA and control group during 60 days period. CLA supplementation in feed significantly increased SFA and decreased MUFA and PUFA fraction in pig muscles.     

猪肉宰后成熟时间对肉松成松品质的影响

以猪后腿肉为对象,研究宰后成熟时间对肉松成松品质的影响。将宰后猪肉置于0～4 ℃条件下成熟,分别于0、3、6、9、12、24、36、48 h取样,测定其pH值、剪切力和肌原纤维小片化指数（myofibrillar framgmentation index,MFI）,并加工成肉松,通过含松率、蓬松度、净蓬松度和绒松度等指标对成松品质进行综合评价。结果表明：猪肉宰后成熟6h pH值为6.01±0.07,剪切力为（51.09±2.60） N,MFI为58.021±1.635,加工成肉松的含松率为（72.27±2.90）%,蓬松度为（6.88±0.11） cm3/g,净蓬松度为（7.68±0.46） cm3/g,绒松度为（2.44±0.27） cm3/g,综合评分为0.084 2;猪肉宰后成熟12 h pH值为5.63±0.04,剪切力为（61.54±3.81） N,MFI为64.41±2.03,进入最大僵直期,此时加工成肉松的含松率为（61.57±2.45）%,蓬松度为（6.25±0.13） cm3/g,净蓬松度为（7.08±0.14） cm3/g,绒松度为（1.60±0.09） cm3/g,综合评分为0.305 0;宰后成熟24、36、48h（处于解僵后期）的猪肉加工成肉松成松品质综合评分相对于6 h内的猪肉较高;综合评分越低,肉松的成松品质越好,因此,宰后成熟6 h之内的猪肉成松品质较好,成熟6 h以后不再适合加工成肉松。