Radical scavenging properties of protein hydrolysates from Jumbo flying squid (Dosidicus eschrichitii Steenstrup) skin gelatin

Gelatin extracted from Jumbo flying squid skin was hydrolyzed with serials of protease. The scavenging effects of gelatin hydrolysates on superoxide and hydroxyl radical were assessed by chemiluminescence analysis. Properase E and pepsin have shown efficient hydrolysis of squid skin gelatin to obtain high radical scavenging activity peptides. The conditions chosen for enzymic hydrolysis of squid skin gelatin with properase E were pH 9.0, 45 °C, 3 h reaction time, and enzyme‐to‐substrate ratio of 1:50. Hydrolysates combining properase E and pepsin showed the best radical scavenging activity. For fragmented hydrolysates by ultrafiltration, fractions UF‐2 (M_w < 2000 Da) had high yield and radical scavenging activity. Copyright © 2006 Society of Chemical Industry     

Physicochemical changes of pepsin-solubilized and insoluble collagen in jumbo squid (Dosidicus gigas) muscle after cooking process

Collagen is the major connective tissue (CT) protein and one of the main constituents of the jumbo squid (Dosidicus gigas). Therefore, physicochemical changes of pepsin-solubilized collagen (PSC) and insoluble collagen (IC) were studied after cooking (100°C/30 min) of muscle (mantle, fins, and arms). Different pyridinoline (Pyr) contents (the major cross-linking molecule in collagen fibers) were found in the fresh muscle of the three anatomical regions. After the cooking process, a decrease from 10 to 30% in the thermal resistance of collagen was observed, depending on the anatomical region and fraction evaluated. Furthermore, the electrophoretic profile, Fourier transform infrared (FTIR) spectroscopy, and the amino-acid profile revealed that structural changes occurred in the two different collagen fractions caused by the thermal process, and the changes were greater in the mantle. Under the conditions applied in this study, collagen fractions from the squid arms showed more stability during the cooking process due to the high cross-linking degree of their fibers.     

Bioactive peptides from collagen hydrolysates from squid (Dosidicus gigas) by-products fractionated by ultrafiltration

The bioactive properties of peptide fractions obtained from the hydrolysis of squid (Dosidicus gigas) by-products collagen, using Protease type XIV and ultrafiltration (UFI), were studied. The basic objective was to improve the bioactivity of squid hydrolysates via the application of UFI. Peptide fractions obtained after UFI had higher antioxidant and antimutagenic activities, but the antiproliferative activity did not improve after UFI. Peptides <5 kDa (Fraction F3) showed higher antioxidant and antimutagenic activities, as well as lower antioxidant and antiproliferative activities than both, peptides >10 kDa (F1) and those within the range of >5 to <10 kDa (F2). Band at lower field observed in FT-IR spectra and proton-peaks observed at higher ¹H-NMR fields, both associated to aromatic amino acids, as well as to other antioxidant amino acids such as hydroxyproline, glycine, arginine and lysine, may explain F3 bioactivity. Ultrafiltration can, therefore, be used to improve some bioactivities of squid collagen hydrolysates.     

明胶添加量对兔皮明胶膜特性与结构的影响

从兔皮中提取明胶制备明胶膜,通过测定不同明胶添加量下膜的机械性能、水蒸气透过率、亚基组成和结构,探究明胶添加量对明胶膜特性与结构的影响。结果表明随着明胶添加量的增加,明胶膜体系内网络空间结构变大,从而膜的厚度增加。力学结果显示,明胶添加量为4 g/100 m L（w/v）时,明胶膜抗拉强度最高（p<0.05）;明胶添加量为6 g/100 m L（w/v）时,明胶膜断裂伸长率最低（p<0.05）。水蒸气透过率结果表明随着明胶添加量的增加,水蒸气透过率呈现上升趋势。凝胶电泳结果显示,明胶添加量为4 g/100 m L（w/v）时,低分子量的蛋白组分产生更多交联,形成蛋白质-蛋白质交联的结构,此浓度下明胶膜的抗拉强度最大。FT-IR分析表明:当明胶添加量增加至4 g/100 m L（w/v）时,酰胺A带向高波数移动,说明肽链上的N-H基团并没有与甘油的-OH基团相互反应,而是明胶分子的官能团之间产生更强的相互作用,形成独特的网络结构。同时,酰胺Ⅰ带曲线拟合结果也表明当明胶添加量为4 g/100 m L时,膜内稳定结构较多,明胶分子之间的相互反应达到最大化,明胶膜的稳定性和成膜性能较优。      

安康鱼皮明胶的制备及性质研究

以安康鱼皮为原料,采用碱法(浸灰法)提取鱼皮明胶,通过正交试验法对安康鱼皮明胶的提取工艺进行优化,并分别对明胶黏度、色价、等电点、氨基酸组成进行了测定。结果表明,优选出鱼皮明胶最佳提取工艺为Ca(OH)2质量分数0.2%、料液比为1∶10、提取温度为10℃、浸灰时间7d,明胶的提取率为11.23%。     

Rheological and physico‐chemical properties of gelatin extracted from the skin of a few species of freshwater carp

The physico‐chemical and rheological properties of gelatin from the skins of three different freshwater carp species, namely Catla catla, (catla) Cirrhinus mrigala (mrigal) and Labeo rohita (rohu), have been assessed and compared with that of gelatin from porcine skin. The average solids yield from the three species of carp varied in the range of 11.8–14.1%. The amino acid profile showed that the porcine gelatin had a higher proportion of imino acids and glycine than carp skins gelatin. The average molecular weight of carp skins gelatin as determined using a gel filtration technique was 233 kDa, while that of porcine skin gelatin was 282 kDa. The gelling temperature of carp skins gelatin was in the range of 6–15.7 °C, and the melting temperature was 17.9–23.7 °C as determined using a controlled stress rheometer. A higher gelling and melting temperature was observed for porcine skin gelatin.     

鮰鱼皮明胶的提取工艺研究

对鮰鱼皮基本成分及其鱼皮明胶的提取工艺进行研究.探讨盐酸浓度、料液比、提取温度和提取时间对鱼皮明胶得率的影响,在单因素试验的基础上,通过正交试验确定最佳提取工艺条件.结果表明:鱼皮明胶提取的最优条件为盐酸浓度 3.5%,料液比 1:4.0,提取温度 70℃,提取时间 4 h时,鱼皮胶的得率约为 12.15%.另外,还测定了鮰鱼皮的基本成分:水分 78.32%,灰分 1.24%,粗蛋白 16.84%,脂肪 3.23%和总糖 0.26%.     

猪皮胶原蛋白的提取与应用浅析

胶原蛋白是动物体内结缔组织的重要结构蛋白,其中富含甘氨酸、脯氨酸和羟脯氨酸.现今,随着胶原提取技术的不断发展及对胶原蛋白功能性质认识的逐步提高,人们对胶原蛋白的应用给予了更多关注.本文在概述猪皮的基本纽分与提取工艺路线的基础上,对胶原蛋白的主要应用及今后的发展趋势进行了系统性阐述.     

Preparation and functional characterisation of fish skin gelatin and comparison with commercial gelatin

Gelatin was extracted from the skin of farmed giant catfish (GC) and tilapia (TP) at a yield of 19.50% and 23.34% (wet wt). It was high in protein (84–88%) but low in fat (0.09–1.24%) and ash content (0.15–0.17%). The GC exhibited lower emulsifying activity (24–35%), but greater foam ability (98–110%), water holding capacity (477–844%) and fat binding capacity (2541–3314%) than commercial beef skin gelatin (BF) (P < 0.05). GC and TP showed comparable functional properties to BF. SDS‐PAGE patterns of TP gelatin showed high band intensity for the α‐ and β‐components, while the lowest band intensity of the major component was found in the BF. From the study, it can be concluded that the farmed freshwater fish skin GC and TP is a prospective source for producing a significant gelatin yield with desirable functionalities. Because of these, fish skin gelatin could be more effectively and widely used in food industries as a good food ingredient.     

罗非鱼皮胶原肽的制备及抗氧化活性研究

采用酶法从罗非鱼皮中制取胶原肽,选用动物蛋白水解酶,当酶的添加量为0.5%,61℃,pH 6.7下水解3 h时,蛋白质的回收率为92.97%,水解度为9.37%.水解产物90%以上相对分子质量低于10 kD的胶原肽.胶原肽对由Fe^2＋引发的卵磷脂脂质体过氧化有一定抑制作用,同时对·OH具备一定的清除作用.     

基于鱼皮明胶的可食膜改性及其应用

鱼皮明胶是一种资源丰富、具有良好成膜性的蛋白源,可食性鱼皮明胶膜的研制已成为食品包装领域的研究热点。本文介绍了鱼皮明胶的基本结构和特性,详细综述了鱼皮明胶可食膜的改性及其应用,旨在为鱼皮明胶可食膜的开发利用提供依据。      

秘鲁鱿鱼不同组织营养成分分析与评价

为实现秘鲁鱿鱼资源的高值化利用,分析秘鲁鱿鱼不同组织(头部、肌肉、内脏、眼部和颈部)的基本营养组成、氨基酸组成、脂肪酸组成和矿物质元素含量,比较其不同组织的营养特性.结果表明,秘鲁鱿鱼不同组织之间营养组成存在显著差异.不同组织水分含量均在75％以上,眼部水分含量最高(84.85％);肌肉的粗蛋白含量最高(18.21％)...     

鱼皮质量分数对热水浸提明胶的性质及其成膜性能的影响

以罗非鱼皮为原料,考察了热水浸提液中鱼皮质量分数对明胶性质及其成膜性能的影响。结果发现,随着鱼皮质量分数的提高,明胶的黏度和凝胶强度都呈现先上升后下降的趋势。当利用明胶制备成蛋白膜时,膜的机械性能也呈现相同的变化趋势。当热水浸提液中的鱼皮质量分数为10.0%时,提取的明胶其凝胶强度为281g,制备的明胶蛋白膜其抗拉伸强度为60MPa。然而,明胶的氨基酸组成和蛋白组分都没有发现明显的差异。根据差示扫描量热分析和圆二色谱分析的结果,表明利用鱼皮质量分数为10.0%浸提时,提取的明胶其无规则卷曲程度相对较小,结果形成的明胶蛋白膜的热稳定性最高。      

Structural characteristics of camel-bone gelatin by demineralization and extraction

Camel bone was demineralized through HCl acidulation process at different concentrations (0.0%, 1.5%, 3.0%, and 6.0%) over 1–5 days. The level of demineralization was acid concentration and soaking time dependent. Highest demineralization (62.0%) was recorded in bone sample treated with 6.0% dilute acid for 5 days. Energy dispersive X-ray spectroscopy (EDX) elemental analysis revealed reduction in Ca and increase in N and H, while O remains unaffected. Particulate characteristics by scanning electron microscope showed an increased surface roughness of bone after demineralization. Fourier transform infrared (FT-IR) analysis of ossein depicted the presence of functional group similar to that of bone protein (collagen). Statistical optimization by central composite design (CCD) revealed a significant quadratic model for optimum values of extraction temperature, pH, and extraction time. The highest gelatin yield from camel bone was 23.66% at optimum extraction condition (71.87°C, pH 5.26, and 2.58 h) and the bloom was 205.74 g. Camel bone is suitable for production of gelatin with good potentials in food and nonfood applications.     

单宁酸和芦丁对马哈鱼鱼皮明胶凝胶性质的影响

为提高鱼皮明胶的凝胶性能,探究了不同质量分数单宁酸、芦丁及二者的氧化态(0％、2％、4％、6％和8％)对马哈鱼鱼皮明胶凝胶强度、色差、微观结构、T2弛豫性质、十二烷基硫酸钠聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate polyacrylamide gel electrophoresis,SDS-PA...     

Original article: Optimisation of extraction conditions and characteristics of skin gelatin from Nile tilapia (Oreochromis niloticus)

Response surface methodology was used to optimise gelatin extraction conditions from the skin of Nile tilapia (Oreochromis niloticus), and characteristics of the gelatin were determined. Concentration of NaOH (%, X₁), alkaline treatment time (h, X₂), concentration of HCl (‰, X₃) and acid treatment time (min, X₄) were chosen for independent variables. Dependent variable was yield of gelatin (%, Y). Optimal conditions were X₁ = 3.2 (%), X₂ = 2.3 (h), X₃ = 0.7 (‰) and X₄ = 84 (min), and predicted value of response optimal conditions was Y = 20.4%. Actual value was 19.3% by verification experiments under optimal conditions. Crude protein content of the tilapia skin gelatin was 88.5%. The content of imino acids including proline and hydroxyproline in the gelatin was 185 residues per 1000 total amino acid residues. Its gel strength was 260 g. The gelling and melting points were 18.0 and 22.4 °C, respectively.     

Lysyl oxidase from jumbo squid (Dosidicus gigas) muscle: detection and partial purification

Lysyl oxidase (LOX) was detected and partially purified from jumbo squid (Dosidicus gigas) muscle, for the first time. A procedure for the purification of LOX from jumbo squid muscle which consisted of urea extraction, Sephadex G‐75 and anion exchange chromatography was developed. Activity of partially purified LOX was 390‐fold higher than the original extract. Two protein fractions with 32 and 24 kDa were detected by SDS‐PAGE. The enzyme was strongly inhibited by β‐aminopropionitrile fumarate, a specific LOX inhibitor. LOX was purified with 3.8% yield, showing a specific activity of 0.078 IU mg^?1 protein. This knowledge will help understand the behaviour of jumbo squid protein during cool storage or manufacture.     

秘鲁鱿鱼皮酸溶性胶原蛋白提取工艺优化及其特性

以秘鲁鱿鱼皮为原料,通过单因素试验及响应面优化法得到秘鲁鱿鱼皮酸溶性胶原蛋白（acid soluble collagen,ASC）最佳提取工艺,并对ASC的理化特性进行研究。结果表明：最佳提取工艺为在4 ℃条件下,冰醋 酸浓度0.47 mol/L、液料比24.5 mL/g,浸泡43 h后,ASC提取率为31.76%;紫外全波长扫描结果表明,所得ASC在 231 nm波长处有最大吸收峰,符合Ⅰ型胶原蛋白特征;凝胶电泳分析表明,提取的ASC含有α1、α2和β链;拉曼光 谱分析表明,所得ASC结构完整,三螺旋结构未受到破坏;ASC的相变温度为50.07 ℃。     

白鲢鱼皮明胶的脱脂方法及其脱脂前后理化特性的研究

为了探究白鲢鱼皮是水产明胶的良好来源,得到低脂肪含量的白鲢鱼皮明胶,本实验研究了白鲢鱼皮的基本成分,白鲢鱼皮明胶的脱脂方法,并对其脱脂前后的理化特性进行对比。通过国标等方法对白鲢鱼皮进行基本成分分析,采用热水提取法制备白鲢鱼皮明胶并添加四种不同型号大孔树脂（D101、X-5、XAD1180、AB-8）以静态吸附的方式对明胶溶液进行脱脂处理。结果表明:白鲢鱼皮富含蛋白质、矿物质元素等,可作为水产明胶的良好来源;经D101型树脂在40℃、树脂添加量为10%的条件下处理的明胶溶液,脱脂效果最佳,脱脂率达到78.94%±2.98%;羟脯氨酸含量由6.77%±0.09%上升到7.17%±0.13%;脱脂前后明胶的紫外光谱均在221 nm处出现最大吸收峰;SDS-PAGE电泳图谱均主要由β,α₁,α₂三条肽链组成;红外光谱图的趋势基本相同,均具有胶原的典型官能团;脱脂后明胶的凝胶强度较脱脂前略有降低;脱脂后的明胶粘度较脱脂前有所增大;脱脂后的明胶中Ca、Mg、Zn含量较脱脂前分别增加了75.96%、284.13%和2.68%,但Cu、Fe、Mn含量较脱脂前分别降低了16.67%、48.11%和15.56%。