盐酸法提取鳗鱼骨钙的工艺研究

研究了盐酸浓度(A)、盐酸用量(B)、提取温度(C)、提取时间(D)对鳗鱼骨钙的溶出率的影响.在此基础上进行了正交试验,确定了鳗鱼骨钙提取的最优组合是A2B3C2D3,即盐酸浓度为3mol/L、盐酸用量4mL、提取温度50℃、提取时间150 min.在最优组合条件下,鳗鱼骨钙的溶出率为81.31％.影响鳗鱼骨钙的溶出率的因素主次顺序为:盐酸浓度＞盐酸用量＞提取温度＞提取时间.     

胃蛋白酶法提取鱿鱼皮胶原蛋白工艺研究

以鱿鱼皮为原料,采用酶法提取胶原蛋白,用正交实验对鱿鱼皮胶原蛋白提取工艺进行优化。结果表明,胃蛋白酶添加量为2000U／g,料液比为1：15,酶解时间14h,酶解pH为1时胶原蛋白提取率最高,最佳工艺下平均提取率为39％。     

胃蛋白酶提取猪皮胶原蛋白的工艺优化与过程模拟

实时检测胃蛋白酶提取猪皮胶原过程中的羟脯氨酸含量,通过计算机软件的处理和模拟,进一步优化胃蛋白酶提取猪皮胶原的工艺条件,同时推测胃蛋白酶的一些重要特性。分别在水解0、2、6、10、14、18、22、26h时,对4组不同胃蛋白酶用量(分别为1%,2%,2·5%,3%)的试样取样检测。采用一阶Hill方程可以较好地模拟胃蛋白酶提取猪皮胶原蛋白的进程,并且符合米氏方程的特征;用一阶指数衰减方程则可以表征胃蛋白酶水解速率的衰减过程。最后得出2%的胃蛋白酶用量和6~7h的水解时间较为合理。     

大鲵骨酸溶性和胃蛋白酶溶性胶原蛋白的提取与表征

大鲵为一种珍贵的两栖动物,营养丰富。为了充分且有效利用其加工副产物,分离并表征了来自大鲵骨的酸溶性胶原蛋白 (ASC) 和胃蛋白酶溶解性胶原蛋白 (PSC)。大鲵骨ASC和PSC的产率分别为10.71%和13.11%。通过傅里叶红外光谱揭示胶原蛋白稳定的三螺旋结构。SDS-PAGE电泳图显示两个样品均为I型胶原蛋白,同时具有高水平的亚氨基酸(179~187/1 000个残基)。样品在pH 6时溶解度最高。热变性温度(45.78~46.51 ℃)显著高于海洋和淡水鱼物种。在SEM下,胶原蛋白显示出致密的片状和不规则的孔洞状。这些结果表明大鲵骨胶原蛋白特性与哺乳动物胶原蛋白相似,具有成为其替代品的潜力,为其后续的研究和开发利用提供了基础数据。     

鮟鱇鱼骨胶原蛋白提取工艺

为了解鮟鱇鱼骨的基本组成和氨基酸成分,提高其胶原蛋白提取率,研究采用酶解法制备低分子量的胶原蛋白。在单因素的基础上,应用正交实验对鮟鱇鱼骨胶原蛋白的提取工艺进行优化。结果表明,鮟鱇鱼骨水分、蛋白质、脂肪、灰分及钙含量依次为76.26%、13.28%、0.0025%、12.32%、6.22%;鮟鱇鱼骨总氨基酸含量76.57%,其中,必需氨基酸31.28%,鲜味氨基酸16.94%,羟脯氨酸含量3.68%;优化胶原蛋白的提取条件如下:提取时间4 h,加酶量6%,温度40 ℃,pH1。在此条件下提取胶原蛋白的含量为43.06%,水解度为27.08%,分子量低于30 kDa的胶原蛋白占总含量的20.65%。实验为深入研究和开发鮟鱇鱼骨胶原蛋白及其相关产品提供了理论和技术基础。     

斑点叉尾鮰鱼骨胶原蛋白的提取与特性研究

选择不同提取剂对斑点叉尾鮰鱼骨胶原蛋白进行提取,并对胶原蛋白进行了部分定性研究。实验结果表明,在4℃条件下,鮰鱼鱼骨先用0.1mol/L的NaOH浸泡6h,再用2.5%NaCl浸泡6h,比单独或同时使用NaOH、NaCl能更好地去除杂蛋白,用10%的异丙醇溶液去除脂肪,0.1mol/L的柠檬酸浸提3d能较好地提取胶原蛋白,无色无味,提取率可达11.87%。粗提液再经盐析、透析,可得到纯度较高的胶原蛋白制品。鱼骨胶原蛋白溶液的粘度随着蛋白浓度的增大而增大,其变性温度为33.9℃。SDS-PAGE实验结果表明,提取的鮰鱼骨胶原具有较高的纯度,含有两条α链,β链含量较高。      

斑点叉尾鮰鱼骨胶原蛋白的提取与特性研究

选择不同提取剂对斑点叉尾鮰鱼骨胶原蛋白进行提取,并对胶原蛋白进行了部分定性研究.实验结果表明,在4℃条件下,鮰鱼鱼骨先用0.1moL/L的NaOH浸泡6h,再用2.5%NaCl浸泡6h,比单独或同时使用NaOH、NaCl能更好地去除杂蛋白,用10%的异丙醇溶液去除脂肪,0.1moL/L的柠檬酸浸提3d能较好地提取胶原蛋白,无色无味,提取率可这11.87%.粗提液再经盐析、透析,可得到纯度较高的胶原蛋白制品.鱼骨胶原蛋白溶液的粘度随着蛋白浓度的增大而增大,其变性温度为33.9℃.SDS-PAGE实验结果表明,提取的鮰鱼骨胶原具有较高的纯度,含有两条α链,β链含量较高.     

胶原蛋白的提取工艺研究

探讨了胃蛋白酶法从猪肌腱中提取胶原蛋白的工艺.从酶浓度和酸浓度两个重要影响因素对工艺进行优化.并利用傅立叶变换红外光谱对胶原结构进行鉴定,同时采用高效液相色谱对所提胶原蛋白进行氨基酸组成分析.     

鳗鱼多肽水解物酶法制备工艺研究

通过单因素实验和正交设计实验进行鳗鱼骨酶解多肽水解物制备工艺研究,结果表明,新鲜鳗骨经清洗减菌预处理后,按1:1比例加入无菌水;然后加入以1:1:1比例混合的中性蛋白酶、复合蛋白酶远天23及风味蛋白酶0.3%,在p H值7.0、温度50℃条件下,水解6h,制备鳗鱼多肽水解物。在此条件下,新鲜鳗骨总氮提取率达71.4%,蛋白质水解率达达50%。鳗鱼多肽水解物风味良好,几乎无苦味。     

齐口裂腹鱼骨胶原蛋白超声波辅助提取工艺及其特性研究

为提高鱼骨胶原蛋白提取效率,在超声波辅助酸法的工艺条件下,采用单因素及正交试验研究齐口裂腹鱼骨胶原蛋白提取方法;采用SDS-PAGE电泳、紫外扫描、氨基酸分析、热变性温度测定分析分离纯化后的胶原蛋白。结果表明,超声波预处理显著提高了齐口裂腹鱼骨胶原蛋白提取得率,最优条件为:提取温度30~℃,液料比751(mL/g),超声波预处理时间20min,提取时间48h,该条件下胶原蛋白得率为6.91%,纯度为89.74%;SDS-PAGE结果显示,齐口裂腹鱼骨胶原蛋白由α1、α2和β链组成,属Ι型胶原蛋白的特征;紫外扫描结果显示,最大吸收峰的波长在220~232nm;齐口裂腹鱼骨胶原蛋白主要由甘氨酸组成,占总氨基酸含量的31.21%,热变性温度为31.4~℃。     

Characteristics of acid soluble collagen and pepsin soluble collagen from scale of spotted golden goatfish (Parupeneus heptacanthus)

Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) were extracted from scale of spotted golden goatfish (Parupeneus heptacanthus) with the yields of 0.46% and 1.20% (based on dry weight basis), respectively. Both ASC and PSC were characterised as type I collagen, containing α₁ and α₂ chains. β and γ components were also found in both collagens. Based on FTIR spectra, the limited digestion by pepsin did not disrupt the triple helical structure of collagen. ASC and PSC contained glycine (336–340 residues/1000 residues) as the major amino acid and had imino acids of 186–189 residues/1000 residues. Maximal transition temperatures (T_max) were 41.58 and 41.01 °C for ASC and PSC, respectively. From zeta potential analysis, net charge of zero was found at pH 4.96 and 5.39 for ASC and PSC, respectively. Both collagens exhibited high solubility in acidic pH (2–4) and were soluble in the presence of NaCl at concentration up to 20 and 30 g/l for ASC and PSC, respectively.     

亚临界醋酸法水解皂脚提取脂肪酸的研究

亚临界的条件下在高压磁力搅拌釜内,采用油脂厂精炼过程中的副产物皂脚,利用弱酸醋酸溶液的中和作用,使反应向正反应方向进行,从而制得有用物质脂肪酸 考察了料液比、反应温度、反应时间、反应压强对皂脚水解率的影响,采用单因素和响应面优化的方法,最终确定反应最优条件为:料液比为1∶2.2,反应温度为290℃,反应时间为45min,反应压强为14MPa,在最优条件下脂肪酸提取率为96.5％.亚临界醋酸水解法与传统提取方法相比,可明显缩短水解时间,无需添加强化学催化剂.     

亚临界醋酸法水解皂脚提取脂肪酸的研究

亚临界的条件下在高压磁力搅拌釜内,采用油脂厂精炼过程中的副产物皂脚,利用弱酸醋酸溶液的中和作用,使反应向正反应方向进行,从而制得有用物质脂肪酸。考察了料液比、反应温度、反应时间、反应压强对皂脚水解率的影响,采用单因素和响应面优化的方法,最终确定反应最优条件为:料液比为1:2.2,反应温度为290℃,反应时间为45min,反应压强为14MPa,在最优条件下脂肪酸提取率为96.5%。亚临界醋酸水解法与传统提取方法相比,可明显缩短水解时间,无需添加强化学催化剂。      

草鱼鱼鳞胶原蛋白酸酶分步提取工艺研究

为实现鱼鳞胶原蛋白的高效提取,在优化脱钙、混酸法和酶法提取工艺基础上,对鱼鳞胶原蛋白的酸酶进行分步提取。研究发现,鱼鳞最佳脱钙工艺为料液比8:100(g/mL),盐酸浓度1.0 mol/L,反应时间1.0 h,反应温度20℃;混合酸法提取鱼鳞胶原蛋白的最佳条件为醋酸料液比1:12(g/mL),柠檬酸料液比1:10(g/mL),乳酸料液比1:12(g/mL),即混合酸料液比为1:34(g/mL),其中,0.8 mol/L柠檬酸、1 mol/L乳酸、0.8 mol/L醋酸的体积比为6:5:6,提取时间2 d,胶原蛋白的提取率为48.14%;最佳酶法提取条件为胃蛋白酶用量450 U/g,提取温度30℃,提取时间72 h,该条件下提取率为45.26%。酸酶耦合法优于单一方法或同种方法两次提取的效果,可实现酸溶性和酶溶性胶原蛋白的连续提取,先酸后酶法胶原蛋白的提取率达84.61%,SDS-PAGE凝胶电泳发现其为Ⅰ型胶原蛋。     

Use of pepsin for collagen extraction from the skin of bigeye snapper (Priacanthus tayenus)

Extraction and some properties of pepsin-solubilised collagens from the skin of bigeye snapper (Priacanthus tayenus) were investigated. Addition of bigeye snapper pepsin (BSP) at a level of 20 kUnits/g of defatted skin resulted in an increased content of collagen extracted from bigeye snapper skin. The yields of collagen from bigeye snapper skin extracted for 48 h with acid and with BSP were 5.31% and 18.74% (dry basis), respectively. With pre-swelling in acid for 24 h, collagen extracted with BSP at a level of 20 kUnits/g of defatted skin for 48 h had a yield of 19.79%, which was greater than that of collagen extracted using porcine pepsin at the same level (13.03%). The skin collagen was characterised to be type I with no disulfide bond. Electrophoretic study revealed slight differences in molecular weight between acid-solubilised collagen and all pepsin-solubilised collagens. The molecular weights of α1 and α2 chains in acid-solubilised collagen were estimated to be 120 and 112 kDa, respectively, whereas α1 and α2 chains of pepsin-solubilised collagens had molecular weights of 118 and 111 kDa, respectively. The result suggested that these pepsin-solubilised collagens might undergo partial cleavage in the telopeptide region by pepsin treatment. The maximum transition temperature (T_max) of acid-solubilised collagen was observed at 32.5 °C, which was slightly higher than that of pepsin-solubilised collagens (by about 1 °C). Generally, all collagens were highly solubilised in the pH range of 2–5 and sharply decreased at the neutral pH. No changes in solubility were observed in the presence of NaCl up to 3% (w/v) and the decrease was more pronounced with increasing NaCl concentration.     

Tuna pepsin: characteristics and its use for collagen extraction from the skin of threadfin bream (Nemipterus spp.)

ABSTRACT:  Pepsin from the stomach of albacore tuna, skipjack tuna, and tongol tuna was characterized. Pepsin from all tuna species showed maximal activity at pH 2.0 and 50 °C when hemoglobin was used as a substrate. Among the stomach extract of all species tested, that of albacore tuna showed the highest activity (40.55 units/g tissue) ( P < 0.05). Substrate-Native-PAGE revealed that pepsin from albacore tuna and tongol tuna consisted of 2 isoforms, whereas pepsin from skipjack tuna had only 1 form. The activity was completely inhibited by pepstatin A, while EDTA (ethylenediaminetetraacetic acid), SBTI (soybean trypsin inhibitor), and E-64 (1-( L -trans-epoxysuccinyl-leucylamino)-4-guanidinobutane) exhibited negligible effect. The activity was strongly inhibited by SDS (sodium dodecyl sulfate) (0.05% to 0.1%, w/v). Cysteine (5 to 50 mM) also showed an inhibitory effect in a concentration dependent manner. ATP, molybdate, NaCl, MgCl₂, and CaCl₂ had no impact on the activity. When tuna pepsin (10 units/g defatted skin) was used for collagen extraction from the skin of threadfin bream for 12 h, the yield of collagen increased by 1.84- to 2.32-fold and albacore pepsin showed the comparable extraction efficacy to porcine pepsin. The yield generally increased with increasing extraction time ( P < 0.05). All collagen obtained with the aid of tuna pepsin showed similar protein patterns compared with those found in acid-solubilized collagen. Nevertheless, pepsin from skipjack tuna caused the degradation of α and β components. All collagens were classified as type I with large portion of β-chain. However, proteins with molecular weight (MW) greater than 200 kDa were abundant in acid-solubilized collagen.     

Hydrogen production by fermentation using acetic acid and lactic acid

Microbial hydrogen production from sho-chu post-distillation slurry solution (slurry solution) containing large amounts of organic acids was investigated. The highest hydrogen producer, Clostridium diolis JPCC H-3, was isolated from natural environment and produced hydrogen at 6.03+/-0.15 ml from 5 ml slurry solution in 30 h. Interestingly, the concentration of acetic acid and lactic acid in the slurry solution decreased during hydrogen production. The substrates for hydrogen production by C. diolis JPCC H-3, in particular organic acids, were investigated in an artificial medium. No hydrogen was produced from acetic acid, propionic acid, succinic acid, or citric acid on their own. Hydrogen and butyric acid were produced from a mixture of acetic acid and lactic acid, showing that C. diolis. JPCC H-3 could produce hydrogen from acetic acid and lactic acid. Furthermore, calculation of the Gibbs free energy strongly suggests that this reaction would proceed. In this paper, we describe for the first time microbial hydrogen production from acetic acid and lactic acid by fermentation.