多菌种混合发酵马铃薯渣产蛋白饲料

马铃薯渣是马铃薯淀粉生产加工过程中产生的副产物。通过微生物发酵可有效改善马铃薯渣的营养价值,从而提高其饲用价值。该文通过研究菌种对发酵马铃薯渣饲料中粗蛋白、粗纤维含量及蛋白酶活、纤维素酶活的影响,为发酵马铃薯渣生产蛋白饲料提供科学依据。采用8株菌种对废马铃薯渣进行固态发酵,以未接菌种的培养基为对照,通过单一菌种、双菌组合、菌种比例的发酵试验,对发酵产物中粗蛋白、粗纤维含量及蛋白酶活、纤维素酶活进行分析。结果表明,黑曲霉Z9和啤酒酵母PJ组合为最佳菌种配伍,且当菌种比例为1∶1时,粗蛋白含量为41.72%,蛋白酶活为1 344.93 U/g,纤维素酶活为120.87 U/g,分别比对照组含量提高了78.69%、296.74%和1 473.77%;粗纤维含量为8.47%,比对照组降低了31.96%。     

马铃薯渣发酵生产活性蛋白饲料的研究

以马铃薯渣为原料,选用啤酒酵母、面包酵母和黑曲霉为出发菌种,探究原料灭菌与不灭菌、菌种配伍及其比例对固态发酵产品中真蛋白含量、酸性蛋白酶活和纤维素酶活的影响。结果表明:发酵原料不灭菌处理条件下,菌种配伍以黑曲霉和啤酒酵母组合最佳,且比例为1∶1时,发酵完成后发酵产品中真蛋白含量最高,可达17.87%,较未发酵前提高171.17%;酸性蛋白酶活和纤维素酶活可达1187.93 U/g和61.77 U/g,可见利用马铃薯渣制备一定生物活性的蛋白饲料是可行的。     

复合发酵棉籽粕营养价值及活性产物分析研究

旨在研究复合固态发酵(两株酵母和一株霉菌)对棉籽粕脱毒效果及营养价值的影响,同时分析测定发酵底物中的活性产物。结果表明:复合发酵可极显著降低棉籽粕底物游离棉酚含量(P0.01),降解率达71.90%;棉籽粕底物粗蛋白、总氨基酸和必需氨基酸含量分别提高28.96%、8.83%、7.58%;发酵54~60 h时底物中蛋白酶活力最高(酸性蛋白酶活力为931.58 U/g,中性蛋白酶活力为1 097.79 U/g,碱性蛋白酶活力为798.62 U/g),纤维素酶活力最高(滤纸酶活力为1 601.66 U/g,Cx酶活力为3 590.02 U/g,C1酶活力为1 685.35 U/g),淀粉酶活力最高为578.05 U/g;同时发酵过程产生了一定量的有机酸。     

稻草粉基混合菌发酵产纤维素酶研究

以稻草粉为主要原料,对白腐菌(White-rot fungi)NS75和黑曲霉(Aspergillus niger)NS83进行固态混合发酵产纤维素酶进行研究。混合菌固态发酵与单菌固态发酵实验结果比较表明,混合菌发酵产生的纤维素酶总体酶活明显高于单菌种发酵,其β-葡萄糖苷酶(β-G)酶活较白腐菌NS75单菌发酵提高了120.9%;葡聚糖内切酶(CMC)酶活比黑曲霉NS83单菌发酵提高了140.8%。单因素实验和正交实验结果表明,当稻草粉麸皮质量比为9∶1,料水比为1∶2,白腐菌NS75与黑曲霉NS83的接种比例为1∶1(v∶v)时,培养第3d开始搅拌,每天搅拌一次,于30℃,培养5d,稻草粉基混合菌发酵产纤维素酶中CMC酶活达到16650U/g,β-G酶活为16108U/g、滤纸酶活(FPA)酶活为3164U/g。     

米渣蛋白酿造酱油的原料配比优化

对米渣蛋白全替代大豆生产酿造酱油的原料配比进行了研究。以蛋白酶活、淀粉酶活为主要制曲指标,确定米渣蛋白最佳加入量为60%,其蛋白酶活达到2224U,淀粉酶活达到290U,发酵30天后,pH为6.18,氨基酸态氮含量为1.022g/dL,还原糖含量为3.518g/dL,色度为0.204。不同淀粉质原料对酿造酱油各项品质指标均有明显影响,炒小麦的蛋白酶活和氨基酸态氮含量最高,分别为2692U和0.936g/dL。面粉淀粉酶活最高,为380U;米粉还原糖含量最高,为4.93g/dL;蒸玉米的色度最高,为0.249。以氨基酸态氮含量和还原糖含量为主要发酵指标,可以确定蒸玉米为最佳淀粉质原料,以米渣代替大豆酿造酱油是可行的。     

响应面法优化全豆腐乳前期发酵条件的研究

采用响应面法优化全豆腐乳前期发酵条件,即在单因素实验的基础上,选取发酵时间、发酵温度、菌种接种量为影响因子,以腐乳毛坯上蛋白酶、脂肪酶、纤维素酶以及α-淀粉酶活力为响应值,应用Box-Behnken中心组合实验设计建立数学模型。研究结果表明,全豆腐乳前期发酵的最优工艺条件为:发酵时间54h、发酵温度30℃、菌种接种量10.3%(以全豆腐乳白坯重量计,孢子悬浮液的浓度约为0.5×107个/mL)。在此最优工艺条件下,全豆腐乳毛坯上蛋白酶活力为208.292U/g,脂肪酶活力为95.835U/g,纤维素酶活力为62.479U/g,α-淀粉酶活力为202.215U/g,各酶的酶活均达到相对较高水平。     

发酵火麻仁乳的工艺优化及抗氧化活性变化

将熟化火麻仁乳作为原料,以乳酸菌复配比例、菌种添加量、发酵温度与发酵时间为自变量,活菌数、酸度、感官评价为评价指标,采用模糊综合评价法通过单因素试验及响应面试验确定火麻仁发酵乳最佳生产工艺配方。实验表明:当保加利亚乳杆菌:嗜热链球菌:干酪乳杆菌:嗜酸链球菌复配比例为2:2:1:1.78、接种量为6.21%、发酵温度为39.42℃、发酵时间为7.12 h条件下时,模糊综合评价值最高,为0.927分,其活菌数、酸度及感官评分分别为1.9×10~8 CFU/m L、78 ~oT和8.74分。发酵后火麻仁乳的总糖、总固形物含量分别为69.29 mg/mL、6.08±0.22 g/100 g,与发酵前相比含量显著降低(p0.05),总酸、总酚和总黄酮含量分别为7.99±0.34mg/m L、28.04±0.82 mg GAE/100 mL、27.11±1.34 mg GAE/100 mL,含量均比发酵前显著提高(p0.05)。抗氧化实验表明,当DPPH自由基清除率、ABTS~+自由基清除率为50%时,发酵后火麻仁乳浓度分别为26.09 mg/mL、7.22±0.13 mg/mL,与0.25 mg/mL和0.13mg/mL生育酚相当,抗氧化活性得到了显著提高(p0.05)。     

黑曲霉固态混菌发酵苹果渣生产多酶生物饲料

苹果渣是一类产量巨大而目前尚未充分利用的农业废弃物资源,其综合利用不仅可产生巨大的经济效益,而且还可以减少环境污染,具有显著的社会效益.本文采用两株黑曲霉对苹果渣进行固态混菌发酵生产多酶生物饲料,同时提高蛋白质与氨基酸含量,改善其营养价值.研究结果表明,采用苹果渣棉粕1:1(w/w)、(NH4)2SO41%(w/w)、KH2PO40.1%(w/w)为最佳培养基,黑曲霉F2与乃最佳配比为2:1(w/w),接种量0.4%(w/w),30℃恒温培养48h,蛋白酶和纤维素酶活力分别为3674U/g和1207U/g,果胶与单宁的降解率分别为99.0%和66.1%,同时,蛋白质与氨基酸的含量提高,可溶性糖含量降低,营养价值得到全面的改善.     

刺梨果渣发酵饲料蛋白的工艺研究

以刺梨果渣为原料发酵生产饲料蛋白。研究以发酵产物中蛋白含量为指标,通过混合菌种进行发酵,筛选出最佳菌种比例,并通过单因素试验和正交试验得到混合菌发酵的最佳工艺条件。结果显示,最佳菌种组合为白地霉/康宁木霉/热带假丝酵母（2∶1∶2）,产物中蛋白质含量为14.87%;混合菌发酵的最佳工艺条件为尿素添加量2%,装料量50 g/250 m L,料液比1∶1（g∶m L）,接种量17%,发酵温度30℃,发酵时间5 d。发酵产物中蛋白质含量较未发酵果渣提高了175.8%,游离氨基酸含量提高了56.3%,可溶性膳食纤维提高了37.34%,适口性得到改善,同时具有刺梨的特殊香味,适合作为饲料添加剂。     

鼠李糖乳杆菌及枯草芽孢杆菌发酵对饲料品质的影响

该研究通过测定发酵饲料pH值、活菌数、乳酸含量及中性蛋白酶活性,筛选出适宜基础饲料发酵的鼠李糖乳杆菌（Lactobacillus rhamnosus）BLCC2-0038和枯草芽孢杆菌（Bacillus subtilis）BLCC1-0281,并对筛选出的鼠李糖乳杆菌和枯草芽孢杆菌进行单菌及混菌发酵方式进行了研究。结果表明,BLCC2-0038单独发酵72 h时pH值降至3.73,活菌数达到7.05×109 CFU/g,乳酸含量为48.67 mg/g;BLCC1-0281单独发酵72 h时,活菌数达到2.28×1010 CFU/g,中性蛋白酶活性达到3 207 U/g;BLCC2-0038和BLCC1-0281混菌发酵时,以鼠李糖乳杆菌/枯草芽孢杆菌配比为3∶1,2%接种量,有氧发酵方式最优,发酵72 h时鼠李糖乳杆菌活菌数为5.35×109 CFU/g,枯草芽孢杆菌活菌数为7.80×109 CFU/g,中性蛋白酶活性为1 407.83 U/g。     

淀粉酶高产菌株的筛选及其酶活的测定

为了筛选对于淀粉降解效果好的淀粉酶产生菌株,从浙江、山东等地富含淀粉的土壤样品中筛选出1株产淀粉酶活力较强的菌株BSJD10,结合茵落形态、生理生化指标和16SrDNA序列分析,对其种群形态和个体形态进行观察和鉴定,确定BSJDl0为枯草芽孢杆菌（Bacillus subtilis）。     

食品水活性的重要性

<正> 水篱罴篙筹兰震圭压,即水溶液压力与在该温度下的最大水蒸气压(纯水)之比:     

Metmyoglobin reducing activity

Meat colour is a major factor that influences the purchase decision by consumers. Many intrinsic and extrinsic factors contribute to the final colour of meat. The role of the MetMb reducing system in maintaining meat colour has been controversial and a considerable amount of work has been published since [Giddings, G. G., 1974. Reduction of ferrimyoglobin in meat. CRC Critical Reviews in Food Technology 5, 143-173] classic review. Historically, the activity of MetMb reductase was classified under different names, for example, diaphorases, aerobic and anaerobic reducing systems, cytochrome b(5) MetMb reductase, and NADH dependent metmyoglobin reducing enzyme system. Several techniques have been proposed to measure the enzyme activity including reflectance spectrophotometry and absorbance spectrophotometry. However, the variations in the reductase systems and techniques used to measure them have yielded inconsistent results from different investigators. This review seeks to characterize the current understanding of metmyoglobin reduction in meat especially with reference to recent developments in this area. Because many systems (different enzymatic systems and non-enzymatic systems) have been reported to reduce MetMb, the term MetMb reductase is not appropriate to be used to reflect "the MetMb reducing activity" in meat. The need for a standardized approach for measuring MetMb reduction is discussed in order for future research to ensure a greater understanding of this important reaction.     

蓖麻碱的生物活性研究进展

从3个方面阐述了蓖麻碱的生物活性及应用前景。在医药方面,具有改善记忆力和肝保护作用;在农药杀虫方面,对天幕毛虫、桃蚜、小菜蛾这3种害虫有不同程度的杀灭作用;在开发新型低毒植物源性杀鼠药品方面,为开发配制新型低毒植物源性杀鼠药品提供科学依据。     

Antibacterial activity of carnobacteria

This is the first report on bacteriocin production of the genusCarnobacterium. A total of 37 strains of carnobacteria were screened for antagonistic activities against other micro-organisms, including enterotoxigenic and pathogenic bacteria such asStaphylococcus aureus andListeria monocytogenes. Eighteen strains have been found to produce bacteriocins or bacteriocin-like substances primarily active against other carnobacteria. The cell-free culture supernatants exhibited inhibitory activity exclusively on bacteria closely related to the producers.L. monocytogenes was inhibited only by a supernatant that was concentrated tenfold. All other Gram-positive and Gram-negative bacteria tested in an agar well diffusion assay were not sensitive to the bacteriocins. The inhibitory activity was eliminated upon treatment with trypsin but was not affected by heating (10 min, 100°C). A bactericidal mode of action was demonstrated by usingCarnobacterium piscicola LV 61.     

Factors affecting lactoperoxidase activity

The extent to which lactoperoxidase (LP) activity was affected while varying the concentration of various compounds normally present in the reaction medium was investigated. LP activity increased with increasing concentrations of 2,2'-azino-bis-3-ethylbenz-thiazoline-6-sulphonic acid (ABTS) but decreased with increasing thiocyanate concentrations. Maximum activity was at 0.1 mm for peroxide. Activity increased in the presence of lactose, whey protein concentrate, sodium, magnesium and calcium chlorides, but decreased in the presence of casein. Activity was similar in either acetate or phosphate buffers but higher in either citrate or succinate buffers. These compounds influence LP activity and should be considered when optimum activity conditions are being established.     

溶菌酶的活性测定

考察比浊法测定溶菌酶的活性,对可能出现的结果差异进行分析,提出实际操作中测定未知样溶菌酶活性的方法。     

低聚木糖抑茵活性的研究

以不同浓度的低聚木糖溶液作为抑菌剂,考察了其对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌和青霉菌的体外抑制作用。采用固体培养牛津杯法和液体培养法进行抑菌试验,分别以抑菌圈大小、菌落数、液体培养基菌体数为指标,确定了低聚木糖的抑菌效果。牛津杯抑菌试验中,出现了直径很小的抑菌圈;布平板菌落计数试验中,同阴性对照菌落数略少;液体培养法中菌体数数量没有明显减少;综上所述低聚木糖不能作为抑菌剂。