酸预处理时间对鲢鱼皮明胶理化性质的影响

本文探究了酸预处理时间对鲢鱼皮明胶理化性质的影响。结果发现,当酸预处理时间从10 min增加到80 min,鲢鱼皮的结构变得疏松,在热水浸提中β肽链等胶原高分子组分易发生降解,提取的明胶其羟脯氨酸含量从61个残基下降到43个残基/1000个氨基酸。不管酸预处理时间多长,提取的鲢鱼皮明胶其等电点均在p H 9.2附近,但长时间的酸处理会使明胶的黏度、凝胶性能和成膜性能下降。当酸预处理时间为10 min时,制备的明胶凝胶强度、膜的抗拉伸强度和断裂延伸率分别为242.67 g、28.24 MPa和65.52%。根据圆二色光谱扫描的结果,发现酸预处理时间对明胶二级结构没有明显的影响,但酸预处理时间越长,提取的明胶在干燥过程中越不易复性形成三股螺旋结构,结果导致成膜性能下降。     

蓝圆鲹酸/碱等电点沉淀法分离蛋白凝胶特性与消化特性

采用酸/碱等电点沉淀（isoelectric solubilization/precipitation,ISP）法制备蓝圆鲹肌肉分离蛋白（acid/alkaline aided protein isolate,API/KPI）,并对全蛋白（total protein,TP）、肌原纤维蛋白（myofibrillar protein,MP）与分离蛋白的理化特性、凝胶特性以及消化稳定性进行比较研究。结果表明,蓝圆鲹肌肉蛋白在碱性条件下溶解性显著高于酸性条件,经优化后的API与KPI的回收率分别为65.0%与84.6%,显著高于MP（54.0%）。KPI、API与MP的脂肪与灰分含量明显低于TP,其中KPI的粗蛋白含量最高。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳显示KPI与API的蛋白组成与TP相近,但KPI与API的氨基酸组成中甘氨酸与脯氨酸含量显著低于TP。质构与流变学分析结果显示,KPI与API的凝胶强度与储能模量（G’）均明显低于TP与MP,其中TP、MP与KPI的储能模量在50～55 ℃会出现明显的下降趋势,表明发生凝胶劣化现象,而API组无明显变化。扫描电子显微镜结果表明,与90 ℃相比,经55 ℃加热处理的KPI、TP与MP组凝胶结构更加疏松、多孔,这与流变学分析的结果一致。体外模拟胃肠液消化实验表明,MP具有最佳的消化性,API与KPI的消化性相当,且显著高于TP。综上所述,利用ISP制备分离蛋白可显著提高蛋白回收率,且分离蛋白的消化性明显优于TP。由于分离蛋白失去凝胶化能力,故可考虑将其应用于食品蛋白配料领域。     

明胶溶液浓度对凝胶体质构特性与凝胶特性的影响研究

文章应用质构仪建立了明胶溶液凝胶体质构特性的评价方法,除了凝冻强度之外,还创新性地首次引入了凝胶破裂时的凝胶强度、坚实性、硬度及弹性等评价指标,指导外界刺激条件下凝胶破裂前凝胶特性的评价。另外,配制1%～10%质量分数的明胶溶液,分别应用质构仪、流变仪及差示扫描量热仪研究了不同浓度对明胶溶液凝胶体的质构特性、升温过程中的凝胶-溶胶转化温度与吸热焓,以及明胶溶液降温过程中的溶胶-凝胶转化温度。结果表明：明胶溶液浓度明显影响凝胶体的质构特性与凝胶特性,同时也影响明胶溶液升降温过程中的凝固温度与熔融温度。凝冻强度、凝胶强度、坚实性、硬度及凝胶-溶胶转化温度、溶胶-凝胶转化温度均随浓度增加出现明显增大,而且与浓度之间存在高度相关性。弹性与弹性模量总体趋势上亦随着溶液浓度的增加而增大,而且在升降温过程中明胶溶液的弹性模量变化表现出明显的物理凝胶特性。     

明胶的凝胶特性及多糖对明胶凝胶特性的影响

本文研究了浓度、pH值、蔗糖、氯化钙、氯化钠对明胶凝胶强度的影响,以及多糖对明胶凝胶特性的影响。结果表明,明胶凝胶强度随明胶浓度的增加而增强;pH值影响明胶的凝胶强度,分别在pH值2和10时取得最大值。蔗糖浓度低于1%时,明胶的凝胶强度随蔗糖浓度增加而增加,当蔗糖浓度高于1%时,明胶的凝胶强度随浓度的增高而下降。明胶的凝胶强度随氯化钠浓度增加而减小,随氯化钙浓度增大而增大。添加卡拉胶、CMC或海藻酸钠等多糖能改善明胶的凝胶特性,提高其凝胶强度。     

不同离子多糖对鱼明胶凝胶特性和结构的影响

为了探究不同种类的离子多糖和多糖含量对鱼明胶(fish gelatin,FG)的凝胶特性及其结构的影响,通过在FG溶液中添加不同含量的3种离子多糖得到FG-多糖复合体,运用质构仪、流变仪、傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)和环境扫描电子显微镜(...     

不同提取温度对白鲢鱼皮明胶理化性质的影响

本实验以白鲢鱼皮为原料提取鱼皮明胶,考察不同提取温度（30、50、70、90、100 ℃）对鱼皮明胶得率和理化性质的影响。结果表明：不同温度条件下提取的鱼皮明胶的紫外吸收峰均在波长218 nm左右;明胶提取率在提取温度为90 ℃时最大,为（86.91±0.98）%;50 ℃条件下提取的鱼皮明胶的凝胶强度最大,为（896.75±117.03）g;聚丙烯酰胺凝胶电泳图谱显示,30、50 ℃条件下提取的鱼皮明胶由α1、α2、β 3 条肽链组成,70、90、100 ℃条件下提取的鱼皮明胶由于明胶分子的热降解,电泳条带不明显;30、50、70、90、100 ℃条件下提取的鱼皮明胶的热变性温度分别为（97.88±2.65）、（108.66±0.43）、（106.48±3.33）、（100.27±2.37）、（99.56±0.37）℃;提取温度越高,明胶的G’’和G’值越小、流变性能越差。     

鱼皮明胶：凝胶特性的影响因素及其改善方法

随着食品和制药行业对不同种类胶原蛋白和明胶的需求不断增加,开发替代哺乳动物明胶的新型原料越来越受到人们的关注。哺乳动物明胶(猪和牛)作为最广泛使用的明胶来源,由于人畜共患病与风俗习惯等方面的问题,其应用受到了一定程度的限制。鱼明胶具有与猪明胶相似的特性,可以作为哺乳动物明胶的替代品应用于食品中。鱼明胶的生产和利用不仅能够提高渔业副产物的利用价值,而且可满足消费者需求。但鱼皮明胶在实际生产加工过程中,其凝胶特性与哺乳动物明胶相比还存在差距,需进一步改善。根据明胶本身的性质或加入其他材料,可以提高胶体的性能,达到增强凝胶特性的效果。文章对影响鱼皮明胶凝胶性能的各种因素进行了总结,以便更好地理解和认识相关问题及研究进展,以期为后期的研究工作提供参考。     

山梨糖醇对兔皮明胶理化特性的影响

主要研究了不同质量浓度山梨糖醇的添加对明胶凝胶特性及结构的影响,结果表明,山梨糖醇的添加可以显著增加明胶凝胶强度,但当山梨糖醇质量浓度高于50 g/L时,体系凝胶强度开始呈现下降趋势;流变学和差式扫描量热分析结果均显示,山梨糖醇的添加可提高明胶的热稳定性,凝胶-溶胶转变温度显著升高。红外扫描结果表明,明胶与山梨糖醇之间主要通过氢键产生相互作用,山梨糖醇的添加促进了明胶分子结构的展开。圆二色谱结果说明山梨糖醇的存在使明胶分子链间交联点增加,恢复三螺旋结构的能力增强,且当山梨糖醇质量浓度为50 g/L时效果最明显,解释凝胶强度的变化原因。实际生产中,适量添加山梨糖醇可改善明胶的凝胶特性,扩大其应用范围。     

冬夏季节对猪皮制备的明胶凝胶特性和溯源性的影响

为探究冬夏两季猪皮提取的明胶在凝胶特性和溯源方面的差异,利用HPLC串联线性离子阱高分辨率质谱技术(linear ion trap/orbitrap high-resolution mass spectrometry,LTQ/Orbitrap MS/MS)、剪切应力流变仪和质构分析仪进行分析.结果显示,夏季猪皮明胶在凝...     

κ-卡拉胶/明胶复配胶对牛奶布丁凝胶性质的影响

蛋白质-亲水胶体混合物的凝胶特性对食品的质地和稳定性有着重要影响。论文重点研究了κ-卡拉胶/明胶复配胶浓度对牛奶布丁凝胶强度、质构特性、水分分布和微观结构等特性的影响。结果表明：随K-G复配胶浓度的增加,体系中凝胶强度、硬度、咀嚼性、内聚性和回复性均显著增大,黏性和弹性变化不显著;牛奶布丁体系中以不易流动水为主,单组分弛豫时间(T_2W)及不易流动水弛豫时间(T₂₂)随K-G复配胶浓度增加而略微增加,当K-G复配胶浓度在0.6%以上时,水分比例(S₂₁、S₂₂、S₂₃)结构相对稳定。微观结构结果表明,K-G复配胶浓度的增加有助于牛奶布丁凝胶体系趋于均一、致密。总体而言,添加0.6%的κ-卡拉胶/明胶的复配胶有助于牛奶布丁的制备。     

Effects of Pretreatment on Properties of Gelatin from Perch (Lates Niloticus) Skin

Fish gelatins obtained from perch fish skin pretreated with various solutions containing acetic acid, sodium hydroxide (NaOH) and sodium chloride (NaCl) were successfully characterized for their nanostructure pattern using field emission scanning electron microscopy. Each pretreatment transformed collagen to gelatin with fibril, zigzag cracks, straight rods, and cross-linked rods nanostructure patterns. Pretreatment solutions also affect the gel yield, gel strength, amino acid profile, and functional groups in perch gelatin as analyzed by Fourier transform infrared spectroscopy. Samples pretreated with NaCl, NaOH, and acetic acid solution showed the highest gel yield (22.84%) and gel strength (179.84 g). Fourier transform infrared spectra for perch gelatins also revealed weak C–N amide II and III bond stretches as well as weak C=O bond stretch.     

Effects of Alkali and Acid Solubilization on Gelation Characteristics of Rockfish Muscle Proteins

ABSTRACT: Solubility of rockfish whole muscle and actomyosin was minimum at pH 5 and gradually increased as the pH was shifted to acidic or alkaline pH. Acidic and alkaline solubilization was followed by isoelectric precipitation induced degradation of myosin heavy chain, resulting in a protein band of about 120 kDa. Both myofibrillar and sarcoplasmic proteins underwent denaturation after acidic and alkaline treatment, exhibiting minimal solubility and absence of endothermic peaks. Acid- and alkali-treated muscle proteins readily aggregated upon heating, showing different dynamic rheological patterns compared with whole muscle and washed mince. Disulfide linkages occurred at a greater extent in gel prepared by alkaline solubilization, resulting in higher breaking force and deformation.     

Physicochemical and Rheological Properties of White-Cheek Shark (Carcharhinus dussumieri) Skin Gelatin

Physicochemical and rheological properties of white-cheek shark (Carcharhinus dussumieri) skin gelatin were determined as a function of either an alkaline-acid or an acid pretreatment. With alkaline-acid pretreatment, the purity of white-cheek shark skin gelatin was increased, with a significantly lower extraction yield, a higher retention of high molecular weight components, and greater preservation of the triple helical structure. Moreover, gelatin from alkaline-acid treated skins showed denser spherical structure, significantly (p < 0.05) different textural properties, better thermostability (T_g = 21°C, T_m = 27.5°C), higher values of both G′ and G″, higher gel strength (330 g), more imino acids (20.3%), and lighter colored gels compared with acid treated white-cheek shark skin gelatin.     

Extraction and Physicochemical Characterization of Greater Lizardfish (Saurida tumbil) Skin and Bone Gelatin

ABSTRACT:  Type A gelatins were extracted from skins and bones of lizardfish and analyzed to determine their functional and chemical properties. Lizardfish skin gelatin had ash content of 2.2 ± 0.3% while bone gelatin had ash content of 12.2 ± 0.2%. Gel strength was 159.1 ± 14 and 135 ± 7.9 g, respectively, for skin and bone gelatins compared to 224.3 ± 7.7 g for porcine gelatin. Gelatin from skin exhibited higher viscosity and lower setting time than bone. Skin gelatin had higher imino acid content than bone gelatin. The total imino acid content was 21.71% and 19.83% for skin and bone, respectively. Both skin and bone gelatins contained more α chains than β and γ components. Both bone and skin gelatins also contained low molecular weight (< α) peptides. The differences in functional properties between the skin and bone gelatins appeared to be related to differences in amino acid composition and molecular weight distribution of the gelatins.     

炮制法对三叶木通果皮果胶提取及理化性质的影响

为提高三叶木通果皮果胶提取率和质量,探究不同炮制方法对三叶木通果皮果胶提取及其理化性质的影响.以未处理的三叶木通果皮生粉和炒制、砂制、醋制、酒制方法处理的果皮粉为原料,酸法提取得到果胶并进行结构表征,测定其果胶提取率、半乳糖醛酸质量分数、酯化度、乳化活性、乳化稳定性及抗氧化性.结果表明:醋制果胶提取率、半乳糖醛酸质量分...     

低热量甜味剂对鳕鱼皮明胶理化及功能性质的影响

以鳕鱼皮明胶为原料,研究木糖醇、三氯蔗糖、甜菊糖和蔗糖对鱼皮明胶物理、流变、功能特性及拉曼光谱的影响。结果表明,甜味剂/蔗糖可以提高凝胶样品的凝胶强度、硬度、热变性温度及焓变值。流变和功能特性研究结果表明,甜味剂/蔗糖可使凝胶样品具有更高的储能模量、耗能模量,起泡性和持水性。拉曼光谱结果显示,混合体系的蛋白二级结构中,无规则卷曲转化为α-螺旋,使得体系结构更稳定。低热量甜味剂可作为蔗糖替代物应用于食品工业。     

Structural Characteristics of Tilapia (Oreochromis mossambicus) Bone Gelatin: Effects of Different Liming Methods

Fish bone is a good source of gelatin. In this study, gelatins were prepared from tilapia bone after the bone was pretreated with alkali protease, desalted immediately by 0.6 mol L^?1 HCl, and hydrolyzed by papain or limed by Ca(OH)₂. Gelatins extracted from papain-treated tilapia bone exhibited space structures similar to those of alkali-treated tilapia bone. Despite this similarity, many differences were observed between these gelatin samples. Compared with alkali-treated gelatin, papain-treated gelatins showed higher values for imino residue content, molecular weight proportion, bloom strength, and viscosity. The bloom strengths of the second and third papain-treated gelatins were 163 and 94 bloom, respectively, which were lower than the bloom strength of the first papain-treated gelatin (189 bloom). The viscosities of the three papain-treated gelatin samples were 4.18, 2.81, and 0.51 mPa.s^?1. The first papain-treated gelatin achieved the highest gelling (16 °C) and melting points (23.9 °C). The yields of the first (5.40%) and second (6.71%) papain-treated gelatins were higher than those of the alkali-treated gelatins (3.33 and 5.76%, respectively). However, the yield of the third papain-treated gelatin (2.27%) was lower than that of the third alkali-treated gelatin (5.42%). More importantly, papain hydrolysis can prevent destruction by Ca(OH)₂ in the bone structure and effectively reduce the denaturation temperature of tilapia bone collagen. Moreover, papain hydrolysis can dramatically reduce the time required for liming (0.8% of traditional liming process spent). Papain hydrolysis is a clean production method that can replace traditional liming.     

微波-快速冻融耦合鱼皮明胶理化性质分析

本实验采用微波-快速冻融耦合处理鱼皮获得鱼皮明胶,并通过等电点、透射比、凝冻强度测定以及十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、流变学特性、氨基酸组成和傅里叶变换红外光谱分析对鱼皮明胶的理化性质进行表征.结果表明:与市场上的A型和B型明胶不同,微波-快速冻融耦合鱼皮明胶等电点为7,在450nm波长处透射比为57.13％,在...