酶法提取芦根多糖的研究

利用纤维素酶从芦根中提取芦根多糖,通过单因素实验和L9(34)正交实验研究了酶的浓度、酶作用的时间、酶作用的温度以及酶作用的pH对芦根多糖含量的影响.实验结果表明:纤维素酶能够显著提高芦根多糖的提取率,并且提取温度是最重要影响因素,其次是酶作用的pH和酶的浓度,酶作用的时间在此实验范围内对测定结果的影响最小,提取的最佳工艺条件为:温度40%、pH4.5、酶浓度O.5%、提取时间2.0h.     

纤维素酶的CMC酶活测定条件的研究

研究和分析了羧甲基纤维素酶(CMC酶)活性测定法的实验条件.通过单因素实验对酶促反应时间、酶促反应温度、pH、测定波长、底物浓度、粗酶液和底物添加量六个影响因素进行了研究.最后结合正交实验、方差分析和多重比较.确定了纤维素酶活力测定的最佳条件组合.结果表明,在pH6.2、粗酶液和底物添加量各为2mL的情况下,影响纤维素酶活力测定的主次因素依次为酶促反应时间、酶促反应温度、测定波长和底物浓度.纤维素酶活力测定的最佳条件为:在酶促反应温度为40℃,pH6.2,底物浓度为10g/L,粗酶液和底物添加量各为2mL,酶促反应时间30min,测定波长为520nm.     

响应面法优化嗜热菌Bacillus sp.B Ⅱ-5产琼胶酶的发酵培养基条件

对印度尼西亚热泉菌Bacillus sp.B Ⅱ-5琼胶酶发酵菌株进行发酵条件优化.在前期实验的基础上,选取蛋白胨、酵母粉、琼胶、氯化钙、氯化钠、初始pH值和接种量作为主要菌株产酶影响因素.再利用Plackett-Burman设计筛选出对酶活影响最为显著的3个因素,即蛋白胨、琼胶和氯化钙;采用最陡爬坡实验逼近最大相应区域后再利用Box-Behnken中心设计及响应面分析法对实验数据进行回归分析,得出最优的产酶培养条件.实验表明产酶最优培养的条件为:酵母粉0.4％、蛋白胨0.665％、琼胶1.160‰,氯化钙7.080 mmol/L、初始pH 7.5、接种量1％和氯化钠添加量4‰.对Bacillus sp.BⅡ-5琼胶酶发酵菌株进行发酵条件优化,并且建立数学模型,为该菌发酵琼胶酶在工业生产应用方面奠定了一定的理论基础.     

藕淀粉增抗工艺的响应曲面法优化研究

利用响应曲面分析法对藕淀粉增抗工艺进行了优化.通过预实验确定最佳淀粉乳浓度为8%.凭借单因素实验确定了普鲁兰酶用量、普鲁兰酶酶解时间、酸解时间三个实验因素的取值范围.利用响应曲面分析法得知.在三个因素中普鲁兰酶用量对抗性淀粉产率的影响最为显著,酶解时间影响最小,确定的最佳生产工艺:普鲁兰酶用量为45.1 ASPU/g藕原料淀粉、酶解时间为58.2min和酸解时间为3.04h.据此工艺参数制得藕抗性淀粉含量达到12.3%.     

紫苏秸秆纤维素酶水解工艺优化研究

研究了紫苏秸秆酶法水解的最佳工艺条件.采用DNS法测定紫苏秸秆水解液中还原糖的含量,从而确定其酶水解率,对酶解时间、酶用量、pH3个因素进行单因素实验分析,再通过正交实验对酶解工艺进行优化.实验结果表明:最佳酶解工艺条件为酶解时间24h,pH5.0,纤维素酶用量720U,在此条件下,酶水解率可达72.42％.     

果胶酶对雪莲果汁澄清效果的影响研究

本文研究了果胶酶时雪莲果汁的澄清工艺.通过单因素实验和正交实验,确定了果胶酶对雪莲果汁澄清的最佳工艺条件为:酶解温度为50℃、pH4.5、果肢酶用量为0.06%、酶解时间为90min.     

菠萝蜜蛋白酶提取方法的比较研究

分别用乙醇法、硫酸铵沉淀法和氯化钠沉淀法提取菠萝蜜蛋白酶,以酶的比活力为指标,采用正交实验得出各方法的最佳处理组合.三种方法的实验结果表明,硫酸铵沉淀法提取得率和酶活力较高,酶活回收率为57.18％.     

绿色木霉和黑曲霉协同酶解稻草秸秆纤维素的效果研究

采用双酶混合酶解可以缓解单一酶酶解过程中存在的产物累积抑制作用.对经过15%氨水预处理后的稻草残渣进行双酶(绿色木霉和黑曲霉)混合酶解实验.单因子实验发现纤维素酶解的最适条件为:纤维素酶加入量为20FPU/g底物、底物浓度为80g/L、pH值4.8、糖化温度为50℃;正交实验表明,酶的用量对酶解效果最为显著,其次是糖化温度,然后是pH,底物浓度对酶解得率的影响较小.最佳的酶解条件为:纤维素酶加入量30FPU/g底物、底物浓度60 g/L、PH4.8、糖化温度为50℃,在此条件下的酶解得率可达到80%.该研究为纤维素的有效利用提供了依据.     

不同水解方式下蚕丝丝素蛋白材料的止血性能

为提升蚕丝丝素蛋白材料的止血性能,采用盐解和酶解2种方式水解蚕丝丝素蛋白,通过冷冻干燥法制备得到2种蚕丝丝素蛋白材料.通过凝胶过滤色谱、水溶性实验、凝血因子实验、血小板黏附实验、酶联免疫吸附实验等分析了2种蚕丝丝素蛋白材料的分子质量、水溶性和止血效果.结果表明:与盐解法相比,酶解所得材料具有较低的分子质量和较好的水溶性...     

酶法提取棉籽蛋白的工艺研究

以脱油脱酚棉籽粕为原料,研究了先用纤维素酶破坏其细胞壁,然后再用碱性蛋白酶酶解制备棉籽蛋白的生产工艺.通过单因素实验和正交实验对提取工艺参数进行优化.实验结果表明,纤维素酶的最佳酶解工艺条件为:酶解pH5.0,酶解温度50℃,加酶量0.4%,酶解时间2.0h.再选用碱性蛋白酶进行酶解,最佳工艺条件为:酶解pH8.5,酶解温度55℃,加酶量4.0%,酶解时间3.0h,此时蛋白提取率可达86.4%.     

Biogenic amine contents in fish and fish preserves

A method developed on the basis of highly efficient liquid chromatography of dansyl derivatives was used to study the content of biogenic amines (tyramine, histamine, cadaverine, putrescine, spermine and spermidine) in fish and canned fish. It was found that only 7 out of 149 samples contained histamine levels exceeding maximum permissible concentration (salted herring, smoked sardines, and salted Siberian salmon). No correlation was recorded between the increase of spermine content and spermidine.     

以淡水鱼加工副产物制备鱼冻的工艺及配方研究

对淡水鱼加工中产生的头、皮、骨和鳞等副产物中的蛋白质进行提取,得到的提取液被用来制备鱼冻。结果表明,副产物中蛋白质的适宜提取条件为加入其重量1.5倍的1%食盐溶液的原料于90℃下恒温提取2h;甜味鱼冻加工的适宜配方为100g提取液、魔芋精粉与卡拉胶(3∶2)的复合胶0.8～1.0g、KCl0.7～1.0g、白砂糖9～10g和柠檬酸0.10～0.15g。     

Fluoride content of fish protein concentrate and raw fish

The fluoride content of fish protein concentrate prepared by the Halifax isopropanol process and also of several possible raw materials was determined by distillation without fusion. The concentration of fluoride in this dry material ranged from 20 to 760 ppm and was dependent upon the raw materials. The major source of the fluoride was the bones which were incorporated in the product to a variable extent. The levels in fresh fillets ranged between 2·3 and 5·4 ppm while whole eviscerated fish contained 3·6-57 ppm fluoride.     

Studies on fish protein concentrate and fish meal from river Nile bolti fish (Tilapia nilotica)

Fish protein concentrate (FPC) from river Nile bolti fish (Tilapia nilotica) was prepared and compared with commercial FPC and fresh bolti fish flesh. Fish meal (FM) from bolti fish offals was prepared and compared with commercial FM and also fresh bolti fish flesh. FPC from bolti fish showed a higher crude protein content but less fat, ash, calcium and sand than the commercial sample, while FM from bolti fish showed a higher content of ash and phosphorus than commercial FM but was nearly similar in crude protein, fat, calcium and sodium chloride. FPC from bolti fish had a higher content of lysine, arginine, aspartic acid, glycine and glutamic acid and a lower content of the other free amino acids. The bolti fish FM had a lower content of total amino acids and the contents of the free amino acids cysteine, glycine, aspartic acid, serine, alanine, valine, and methionine increased slightly. The yield was 12% for FPC and 19.5% for FM. Coliform bacteria were not present in both FPC and FM from bolti fish. Low moisture contents of FPC and FM were essential for preventing microbiol growth and to attain a good keeping quality. The FPC and FM from bolti fish reached moisture equilibrium and stopped increasing in weight within 144 to 192 h.     

Production and quality of fish fingers from different fish species

Abstract Production of fish fingers was achieved by using fish species such as sardine (Sardina pilchardus, Walbaum, 1792), whiting (Merlangius merlangus, Linnaeus, 1758) and pike perch (Sander lucioperca, Linnaeus, 1758). Quality changes of battered fish patties during a period of 8 months at –18 °C were investigated. According to the results of microbiological and chemical analysis, fish fingers were found to be within acceptable limits during frozen storage for 8 months. However, sensory analysis showed that, at the end of the frozen storage, fish fingers made from sardine could not be consumed because of rancidity.     

Biological value of protein from raw fish and canned fish

The authors evaluated the nutritive value of protein from 4 kinds of raw fish (herring, cod, mackerel, sprat) and its preserves. Experiments were made on rats fed the diets containing fish protein (8-10% of the total diet). Experiments included the determination of apparent and genuine digestibility, net protein utilization, and net dietary protein caloric value. Evidence was obtained that protein from fish and its preserves is characterized by high digestibility coefficient as compared with casein and egg powder. The highest net protein utilization was noted in animal groups fed the diet containing protein from raw fish. Protein assimilability from fish preserves was on the average 15% lower than that from raw fish.     

DNA-based identification of fish species implicated in Puffer fish poisoning

A method for identification of fish species using three different mitochondrial DNA regions, 16S rRNA, cytochrome b and cytochrome c gene fragments, was investigated. The combined use of all three regions enabled reliable species identification in not only raw fish, but also dried, seasoned and boiled fish, products. Furthermore, the method was applicable even to vomitus from a patient involved in a puffer fish poisoning incident. However, further improvement is necessary to discriminate between closely related species such as Takifugu rubripes and T. chinensis, because they showed close similarity in the nucleotide sequences in the three gene fragments analyzed in this study.     

鱼制品脱腥脱苦技术研究进展

概述了鱼制品腥味苦味产生的机理、脱除方法以及国内外的研究进展,简要介绍了物理法(包埋法、吸附法、盐溶法、掩盖法、有机溶剂萃取法和微胶囊法)、化学法(酸碱法、抗氧化剂法、酶法和类蛋白法)和微生物法三大类技术,并对各种技术方法的脱腥脱苦机理及优缺点进行了简要说明。