鱼明胶改性技术及其产品在食品包装中应用研究进展

鱼明胶是从鱼皮、鱼骨、鱼鳞等鱼类组织中提取出的一种生物高聚物,具有良好的生物相容性和独特的溶胶-凝胶可逆转变特性,是新型食品包装材料的重要原料来源之一,并已逐步在生物医药、食品工业等领域发挥重要作用。与传统的石油基包装材料相比,鱼明胶具有来源丰富、易交联改性、无宗教限制、安全性高等特性,但不同的提取方法、鱼种来源和处理方式对鱼明胶特性影响较大,且天然明胶存在凝胶强度、流变性差等局限性,通常需要通过酸、天然物质、酶等物质的联合改性对其成膜特性进行改善。该文综述了不同来源的鱼明胶特点、改性方法及其在食品包装领域的研究现状,以期为新型食品包装材料的发展提供理论依据。     

高强度明胶基水凝胶的研究

综述了高强度明胶基水凝胶的研究进展,总结了交联改性、与其他高分子材料共混、与纳米填料复合等方法对提高明胶基水凝胶力学强度的影响,为拓展明胶基水凝胶在生物结构材料方面的应用提供了必要的支持。     

不同凝胶体系对大蒜油挥发性风味成分的缓释作用

为研究不同凝胶体系对蒜油挥发性风味成分的控释作用,采用固相微萃取-气质联用技术分析不同凝胶体系中蒜油风味在贮藏过程中的变化情况,并通过稳态流变学方法分析不同凝胶体系对蒜油风味物质的缓释作用。结果表明,蒜油凝胶中主要挥发性物质为含硫化合物、烯烃、醇、醚、醛类化合物等,其中硫醚类化合物中的二烯丙基二硫醚相对百分含量最高。与对照相比,明胶/果胶、明胶/黄原胶、明胶/阿拉伯胶和明胶4种凝胶体系对蒜油中主要挥发性物质具有明显的束缚作用与缓释效果,其中明胶/阿拉伯胶凝胶体系的效果最好,其次是明胶/黄原胶、明胶/果胶体系,单一明胶体系的效果相对较差。不同凝胶体系的黏度变化差异在一定程度上解释了其对挥发性物质控释效果的差异。     

明胶与合成高分子复合膜的研究进展

明胶是一种绿色的天然高分子,来源广泛,价格低廉,具有良好的成膜性、生物相容性、生物降解性等。明胶用作膜材料时,具有广泛的用途。但纯明胶膜存在着质脆、力学性能差、对水敏感、潮湿环境下易霉变等缺陷,通常需要对其进行改性处理。将明胶与合成高分子复合制备明胶基复合膜,往往赋予其良好的性能和特性,从而使明胶复合膜具有广阔的应用前景。简单综述了明胶与一些合成高分子(聚乙烯醇、聚乳酸等)共混复合制备明胶基复合膜的研究进展。     

高G型海藻酸钠-明胶pH敏感型复合水凝胶的制备与性质

以碳酸钙和葡萄糖酸内酯为缓释钙源,采用共混法制备高G型海藻酸钠-明胶(HGAGNa-GT)复合水凝胶,研究不同复配比例对高G型海藻酸钠-明胶复合水凝胶性质的影响。研究结果表明,在复合水凝胶中,高G型海藻酸钠与明胶之间存在强烈的相互作用和良好的相容性。随着复合水凝胶中明胶所占比例的增加,其凝胶弹性逐渐增大,凝胶硬度呈先增大后减小的趋势。水凝胶的储能模量和损耗模量均随明胶所占比例的增加呈先升高后降低的趋势。水凝胶的凝胶时间随温度的降低逐渐缩短,随明胶所占比例的增加逐渐延长。高G型海藻酸钠-明胶复合水凝胶微球具有良好的pH敏感性,在模拟小肠液和结肠液中的溶胀度较高,并最终于模拟结肠液环境下降解。当海藻酸钠与明胶的复配比例为5∶3时,水凝胶的凝胶网络结构最为牢固,此时的水凝胶在模拟小肠液和结肠液中的溶胀率最高,分别为26.31%和34.25%。     

阿魏酸改性明胶的性质变化研究

本文将不同浓度的阿魏酸用于明胶改性,用以研究其对明胶凝胶强度、流变性等主要性质的影响。利用凝胶强度检测、流变学分析、红外分析、X-射线衍射和扫描电镜分析法对明胶改性前后的性质做了分析比较。结果表明,阿魏酸可以提高明胶的凝胶强度和熔点。当阿魏酸总浓度为2.00 g/L时,明胶的凝胶强度得到明显提高。通过红外光谱的分析和X-射线衍射分析可以证实阿魏酸分子与不同的肽链交联,拉近了肽链之间的距离,使肽链间连接更紧密,而交联作用的主要作用力是氢键。本文研究表明,阿魏酸在特定浓度下可作为明胶良好的改性剂。      

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。     

基于凝胶特性改善的多糖-明胶互作及调控研究进展

明胶、多糖凝胶是食品工业中常见的两类大分子亲水胶体,应用广泛,但明胶胶体存在凝胶网络稳定性不足、热稳定性差且受宗教因素限制等缺陷,多糖凝胶则普遍存在机械强度低、水蒸气阻隔性弱等不足。明胶与多糖可通过非共价或共价作用进行互作,产生表面选择性贴片结合、排空效应、共凝胶等现象进而改变体系的凝胶性质。通过调控pH值、混合比、温度等条件影响混合体系结构形成,改善复合凝胶的凝胶特性,可以得到具有独特性能的不同类型的复合胶体系统,进一步制备纳米/微米颗粒、水凝胶、薄膜、乳液和泡沫等。本文针对多糖和明胶凝胶存在的问题、二者的互作机制及其对凝胶特性的改变,通过外界条件变化调控复合凝胶特性等方面进行综述,以期为多糖-明胶复合凝胶在食品工业中更广泛的应用提供理论依据。     

一种香醋凝胶软糖的研制

以蔗糖、麦芽糖浆、香醋、明胶和变性淀粉的复配凝胶为主要原料,通过正交试验法优化香醋凝胶软糖的工艺配方。结果表明,香醋凝胶软糖的最佳配方为:明胶和变性淀粉(2∶1)添加量10%,蔗糖添加量20%,麦芽糖浆添加量27%,香醋添加量10%,以该配方制备出的软糖富有光泽,酸甜可口,并具有良好的咀嚼性。     

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。     

鱼明胶特性及改性对其品质影响的研究进展

明胶是由胶原蛋白部分热水解得到的一种天然多肽聚合物,其由于独特的功能特性而在医药、食品等领域广泛应用。与哺乳动物明胶相比,鱼明胶来源广泛且满足一些特殊人群需要,是一种最具有开发潜力的新型明胶原料。然而,鱼明胶的凝胶性、乳化、起泡和成膜等功能特性较差,在一定程度上限制了其应用。本文对鱼明胶的物理、化学和功能特性展开综述,并总结了近年来有关改善鱼明胶品质的方法,以期为后期相关科研工作者进一步提高鱼明胶的性能和扩大其应用提供一定的理论依据。     

Use of beef,pork and fish gelatin sources in the manufacture of films and assessment of their composition and mechanical properties

This study investigated the properties of different types of gelatin films from solutions of varying gelatin concentrations (4–8 wt %). Gelatin derived from beef, pork and fish skin sources was used to manufacture films using a casting approach. Mechanical properties of gelatin films, water vapour permeability (WVP), oxygen permeability, oil permeability and aqueous solubility of films were evaluated. FTIR spectroscopy was utilized to assess the composition of various gelatin sources so as to determine differences in composition of these sources and ultimately, in overall functionality. High concentration gelatin films had good mechanical properties with tensile and puncture strengths being particularly improved. Gelatin films manufactured from fish skin had the lowest WVP values for each concentration used. All gelatin films possessed excellent barriers to oxygen and oil. Films derived from pork gelatin exhibited lowest water solubility compared to those formed using beef and fish gelatin sources, regardless of the concentrations used. FTIR spectra showed that plasticizer and gelatin were well mixed and interacted well together. The use of higher concentrations of gelatin had the effect of increasing the wavenumber of amide-A in films due to greater interaction occurring between gelatin functional groups.     

明胶及其改性物作为造纸增强剂的应用

明胶具有优良的性质,作为造纸增强剂很有发展前景。简要介绍了明胶的性质及制备,着重讲述了明胶及其改性物作为造纸增强剂的应用情况,并对其发展作出展望。     

明胶基生物可降解薄膜的研究进展

生物可降解薄膜用作聚乙烯保鲜膜的代替品是降低能源消耗,减少环境污染的策略之一。明胶本身易成膜,但明胶膜韧性差、易断裂和易吸水,这些缺点可以通过与其他生物大分子共混或交联改性的方法来解决。本文对作为食品包装材料的明胶基生物可降解薄膜研究成果及各类复合膜相应的物理化学性能进行综述,复合天然高分子化合物在改善明胶膜缺陷的同时,也赋予复合膜良好的拉伸强度和断裂伸长率,并且运用在肉类和果蔬类保鲜上可有效地阻隔氧气和二氧化碳,具有可观的发展前景。通过综述也对不足之处进行了展望,旨在阐明此领域研究的现状及发展趋势,为生物基可降解薄膜的改进提供思路与方向。     

鸡骨明胶与茁霉多糖共混成膜性研究

鸡骨明胶具有良好成膜性,明胶浓度为8%,明胶与甘油质量比为6∶1时,明胶膜具有透明光泽、机械强度高。鸡骨明胶与茁霉多糖混合体属热力学不相容体系,共混膜的性质强烈依赖于二者的比例,当m(明胶)∶m(茁霉多糖)=4∶1时,共混膜的阻氧能力提高。制得的胶囊壳的贮藏稳定性好,贮藏过程胶囊的崩解延时现象得到改善。     

Functional properties of gelatin from cuttlefish (Sepia pharaonis) skin as affected by bleaching using hydrogen peroxide

Functional properties of gelatin from dorsal and ventral skin of cuttlefish with and without bleaching by H₂O₂ at different concentrations (2% and 5% (w/v)) for 24 and 48 h were studied. Gelatin from skin bleached with 5% H₂O₂ for 48 h showed the highest yield (49.65% and 72.88% for dorsal and ventral skin, respectively). Bleaching not only improved the colour of gelatin gel by increasing the L^∗-value and decreasing a^∗-value but also enhanced the bloom strength, and the emulsifying and foaming properties of the resulting gelatin. Gelatin from bleached skin contained protein with a molecular weight of 97 kDa and had an increased carbonyl content. Fourier transform infrared spectroscopic study showed higher intermolecular interactions and denaturation of gelatin from bleached skin than that of the control. These results indicated that hydrogen peroxide most likely induced the oxidation of gelatin, resulting in the formation of gelatin cross-links, giving improved functional properties.     

Bovidae-based gelatin: Extractions method,physicochemical and functional properties,applications, and future trends

Gelatin is one of the most important multifunctional biopolymers and is widely used as an essential ingredient in food, pharmaceutical, and cosmetics. Porcine gelatin is regarded as the leading source of gelatin globally then followed by bovine gelatin. Porcine sources are favored over other sources since they are less expensive. However, porcine gelatin is religiously prohibited to be consumed by Muslims and the Jewish community. It is predicted that the global demand for gelatin will increase significantly in the future. Therefore, a sustainable source of gelatin with efficient production and free of disease transmission must be developed. The highest quality of Bovidae-based gelatin (BG) was acquired through alkaline pretreatment, which displayed excellent physicochemical and rheological properties. The utilization of mammalian- and plant-based enzyme significantly increased the gelatin yield. The emulsifying and foaming properties of BG also showed good stability when incorporated into food and pharmaceutical products. Manipulation of extraction conditions has enabled the development of custom-made gelatin with desired properties. This review highlighted the various modifications of extraction and processing methods to improve the physicochemical and functional properties of Bovidae-based gelatin. An in-depth analysis of the crucial stage of collagen breakdown is also discussed, which involved acid, alkaline, and enzyme pretreatment, respectively. In addition, the unique characteristics and primary qualities of BG including protein content, amphoteric property, gel strength, emulsifying and viscosity properties, and foaming ability were presented. Finally, the applications and prospects of BG as the preferred gelatin source globally were outlined.     

Soft and Ca-retaining Gelatin Prepared by Conjugating with Acidic Saccharides

ABSTRACT: Gelatin samples conjugated with acidic saccharides such as glucuronic acid, alginic acid oligosac-charide, and low-molecular-weight alginic acid were prepared to improve the functional properties of ossein gelatin by the Maillard reaction. The conjugation resulted in a decreased isoelectric point, retardate gelation time, low storage modulus, and low melting temperature and enthalpy of gelatin gel; in particular, low-molecular-weight alginic acid resulted in a large improvement. The alginic acid oligosaccharide-conjugated gelatins and low-molecular-weight alginic acid-conjugated gelatins had calcium-retaining ability, and the latter exhibited calcium-aggregating ability. It is thus considered that conjugation with low-molecular-weight alginic acid could be effective for providing a new type of gelatin with a soft texture and calcium-retaining and calcium-aggregating ability.     

Adding enzymatically modified gelatin to enhance the rehydration abilities and mechanical properties of bacterial cellulose

Bacterial cellulose (BC) possesses excellent water holding capacity. However, increased crystallization causes a decrease in the rehydration ability of dried BC. Due to its excellent hydrophilic properties, we used gelatin and its enzymatically modified form (EMG) to prepare BC nano-composites in an attempt to enhance the rehydration abilities properties of BC. The polar peptide fraction was increased by extended hydrolysis of fish gelatin in Alcalase. Peptides smaller than 10 kDa were obtained by hydrolysis at 50 °C for 20 min. Protein contents of composites prepared by immersing BC in 5% gelatin (Gelatin/BC) or EMG (EMG/BC) solution were 81% and 92%, respectively, both of which then formed high gelatin/BC composites (HGBC). The protein content of EMG/BC was higher than that of Gelatin/BC, as compared with low gelatin/BC composites (LGBC) that were formed by immersion in a corresponding 0.5% solution. Among both HGBC and LGBC composites, EMG/BC exhibited the best rehydration abilities. Freeze-dried EMG/BC also exhibited the fastest rehydration rate and the best ability to restore wet-type composites. Composite microstructures revealed that BC was enveloped by gelatin when non-polar EMG (NPEMG) and polar EMG (PEMG) entered the BC network and adsorbed onto cellulose ribbons. The microstructure of EMG/BC contained both PEMG/BC and NPEMG/BC structures. Gelatin hydrolysates, penetrating BC networks and forming stable composites, improved the rehydration ability of dried BC. The polar functional groups of gelatin and its hydrolysates represent the key factors contributing to the hydrophilic nature of composites.     

添加物对明胶改性作用研究进展

明胶是胶原蛋白水解后的多肽化合物,广泛应用于医药、食品等行业,但其自身的理化特性无法满足各行各业的生产需要(特别是鱼皮明胶),因此对明胶的改性研究越来越多。文章主要综述无机物(MgSO_4、CaCl_2和NaCl)、有机物(果胶、壳聚糖和醛等)及谷氨酰胺转氨酶等添加物对明胶改性,以及改性对明胶应用的影响。