流苏花黄酮类化学成分的分离鉴定

为了提高可食性膜的透明度和阻隔性,制备一种速溶的普鲁兰多糖-明胶可食性膜。将普鲁兰多糖添加到明胶膜中,普鲁兰多糖和明胶的添加质量比为2∶5（PG2）。在此配比下,普鲁兰多糖-明胶可食性膜的抗拉强度是明胶可食性膜的120%,氧气透过率是明胶可食性膜的1/13。可食性膜PG2中普鲁兰多糖和明胶分子间具有较强的氢键作用,并且此时可食性膜具有较好的相容性,因此使可食性膜PG2抗拉强度增强和氧气透过率降低。可食性膜PG2具有较低的氧气透过率（0.15 mL/（m2•d））、较高的抗拉强度（97.21 MPa）和溶水时间（29.5 s）,而且具有不透油和低水蒸气透过率（109.08 g/（m2•d））的性质,因此,可食性膜PG2是适合应用于可食性内包装的材料。     

普鲁兰多糖-明胶可食性膜的特性

为了提高可食性膜的透明度和阻隔性,制备一种速溶的普鲁兰多糖-明胶可食性膜。将普鲁兰多糖添加到明胶膜中,普鲁兰多糖和明胶的添加质量比为2∶5（PG2）。在此配比下,普鲁兰多糖-明胶可食性膜的抗拉强度是明胶可食性膜的120%,氧气透过率是明胶可食性膜的1/13。可食性膜PG2中普鲁兰多糖和明胶分子间具有较强的氢键作用,并且此时可食性膜具有较好的相容性,因此使可食性膜PG2抗拉强度增强和氧气透过率降低。可食性膜PG2具有较低的氧气透过率（0.15 mL/（m2•d））、较高的抗拉强度（97.21 MPa）和溶水时间（29.5 s）,而且具有不透油和低水蒸气透过率（109.08 g/（m2•d））的性质,因此,可食性膜PG2是适合应用于可食性内包装的材料。     

转谷氨酰胺酶(mTG)改性明胶可食性薄膜的制备

以转谷氨酰胺酶（mTG）改性明胶为基料、丙三醇为增塑剂制备可食性食品包装薄膜。研究了mTG、丙三醇的添加量以及膜的成型方法对产品的抗张强度、最大伸长率、韧性、水溶性、吸水性等物理机械性能的影响；筛选出了最佳工艺条件。     

荆条油制备、分析及在食用香精配方中的应用

采用同时蒸馏萃取方法制备了荆条油，气质联机分析鉴定出50个挥发性成分，主要为β-丁香烯（质量分数34．4％）、香桧烯（质量分数7．0％）、反-β-金合欢烯（质量分数5．4％）、β-甲基紫罗兰酮（质量分数4．1％）、1，8-桉叶油素（质量分数2．3％）等。使用荆条油调配出薄荷香精、留兰香香精、菜莉香精、柠檬香精、甜橙香精、柚子香精等9个食用香精配方，可用于牙膏、口香糖、冷饮饮料等食品的加香。     

TG对大豆蛋白／PVA复合膜透湿性、透气性影响研究

以大豆蛋白和聚乙烯醇（PVA）为主要原料,以透H2 O率、透O2率、透CO2率为评价指标,通过单因素试验和正交试验,研究了谷氨酰胺转氨酶（简称TG）对大豆蛋白/PVA复合膜透湿性、透气性的影响。试验结果表明：当反应pH值为5．0,TG添加质量分数为0．22‰;反应温度为53℃时得到性能最佳的复合薄膜。     

聚乙烯醇降解菌的选育及降解特性研究

从印染废水及污水处理厂污泥中分离得到7株聚乙烯醇(PVA)降解菌，经紫外线诱变，获得高活性变异菌株UV2．对UV2进行PVA降解试验，确定了其降解特性参数，并与出发菌株B自的降解性能相比较．研究表明，诱变菌株W2对模拟废水中PVA的降解速率及降解活性均明显高于出发菌株B白，且适应环境的能力更强．在最佳降解条件下，对PVA的降解率达93％以上，比出发菌株提高了30％．     

棉短绒薄膜的浸渍施胶工艺研究

采用浸渍法对棉短绒纤网施胶,制备棉短绒农用薄膜.对三种施胶用的黏合剂进行了筛选,用正交试验法研究了浸渍施胶工艺参数(烘燥温度、胶液浓度和纤网面密度)对农用薄膜性能的影响.试验结果表明:棉短绒薄膜浸渍施胶的最佳黏合剂是聚乙烯醇(PVA),最优工艺参数是烘燥温度100℃、胶液中PVA质量分数2％、纤网面密度35 g/m2,...     

降胆固醇乳酸菌WB的微胶囊化研究

研究了降胆固醇乳酸茵wB的微胶囊化工艺,并对微胶囊化后的产品进行了评价.以海藻酸钠、明胶为壁材.含有降胆固醇乳酸茵wB的硅藻土为芯材,采用W/O/W复相乳化法制备微胶囊.通过单因素和正交试验确定最佳制备工艺条件为:乳酸茵WB菌悬液质量分数为20%,内层水相中海藻酸钠和明胶的质量分数分别为2%和3%,外层水相中明胶质量分数为12%.以该工艺制备的乳酸茵WB微胶囊具有较好的耐酸性和肠溶性,产率在86.62%左右,10℃下储存30d,产品中活茵教仍可达到108mL-1,体外胆固醇降解率可达到36.07%.     

完全降解纸基棉质地膜的制备及性能研究

利用废弃棉纤维经湿法造纸工艺制备可完全降解农用地膜.通过正交试验对抄造工艺进行优化设计,抄造制得的纸基棉质地膜小样经石蜡浸溃、聚乙烯醇(PVA)胶液后处理,得到纸基棉质地膜试样,并对试样的主要物理性能进行了测试.结果表明:在面密度35g/m2、胶液PVA质量分数4％、打浆度40°SR工艺条件下制得的纸基棉质地膜具有良好...     

谷氨酰胺转氨酶对大豆蛋白／PVA 复合薄膜性能的影响

以大豆蛋白和聚乙烯醇（ PVA）为主要原料,以抗张强度、断裂伸长率、透光率、吸水率为评价指标,通过单因素试验和正交试验,研究了谷氨酰胺转氨酶（简称TG）对大豆蛋白/PVA复合薄膜性能的影响。试验结果表明：当反应pH为5．0,反应温度为55℃,TG添加质量分数为0．20‰时得到性能最佳的复合薄膜;在最佳条件下,薄膜的抗张强度、断裂伸长率、透光率和吸水率分别为8．06 MPa,89．97％,30．8％和46．43％。     

提高明胶可食膜机械强度和热封强度的研究

研究了明胶可食膜的机械强度和热封强度。结果表明：明胶可食膜的机械强度和热封强度受干燥温度的影响大,随干燥温度的升高,明胶膜机械强度和热封强度均呈先递增后递减的变化趋势,其最适干燥温度为６０℃;掺用少量琼脂（０．０２％）可明显改善明胶膜的机械强度和热封强度,特别是其断裂伸长率;用０．２％甘油增塑的明胶膜,其抗拉强度,直角撕裂强度均有所改善,但其热封强度稍有下降;明胶膜在贮藏过程中（－１８、０、２０、４０℃,相对湿度６５％）,其机械强度先递减后趋于稳定,但其热封强度变化不明显。     

Using Liquid Smoke to Improve Mechanical and Water Resistance Properties of Gelatin Films

Improvement of mechanical and water barrier properties is critical for gelatin films when applied to edible food packaging. A liquid smoke (LS) obtained from hawthorn nucleus was used to improve the performance of gelatin film based on its abundant compounds. Through SPME‐GC‐MS analysis, 86 volatile and semi‐volatile chemical compounds was detected in LS, in which the total carbonyl compounds were 27.60%, with the main aldehyde as 2‐furaldehyde (9.83%). For gelatin films, an observable influence of LS on film transparency was observed in gelatin films, but not for its thickness and microstructure. Desirably, adding LS into gelatin solution increased the tensile strength of the films, with a better value of 16.38 MPa as 3 wt% LS added, compared with the control (10.30 MPa). Accordingly, film elongation decreased with a LS dependent manner. Furthermore, the water resistance properties of gelatin film were improved by the LS addition, which was supported by the results of water contact angle, water vapor permeability. Moreover, the addition of LS also led to a higher insolubility for gelatin films. Also, thermal stability of the LS treated gelatin films was slightly enhanced with the DSC analysis. According to the FTIR spectra and crosslinking degree detection results, all the above enhancing of gelatin film should be attributed to the crosslinking between carbonyl groups in LS and amide functionalities in gelatin based on nucleophilic reaction.     

桔子精油优化鱼鳞明胶膜性能的作用研究

为改善鱼鳞明胶膜的性能,测定添加明胶质量的0%、25%、50%、75%、100%桔子精油的可食膜的厚度、机械性能、水溶性、水蒸汽透过率、色泽、透明度和透光率、热性能、红外光谱和抑菌活性。结果表明:随着精油浓度的增加,鱼鳞明胶膜的厚度、断裂伸长率增加,拉伸强度、透光率、水溶性降低,水蒸汽透过率呈现先增加后降低的趋势;差示扫描量热法(DSC)和傅里叶变换红外光谱(FTIR)分析结果表明,鱼鳞明胶分子与桔子精油的部分成分发生相互作用,在一定程度上改善了明胶膜的热稳定性;桔子精油的添加还赋予了鱼鳞明胶膜抑菌作用。综合评价得出75%质量浓度的桔子精油添加量对鱼鳞明胶膜各项性能优化效果最好,本实验结果可为生产高性能的鱼鳞明胶膜提供理论基础。     

Development of films based on blends of gelatin and poly(vinyl alcohol) cross linked with glutaraldehyde

Both gelatin and poly(vinyl alcohol) (PVA) can be cross linked with glutaraldehyde (GLU). In the case of gelatin, the GLU reacts with each ε-NH2 functional group of adjacent lysine residues, while for PVA, the GLU reacts with two adjacent hydroxyl groups, forming acetal bridges. Thus it can be considered possible to cross link adjacent macromolecules of gelatin and PVA using GLU. In this context, the aims of this work were the development of biodegradable films based on blends of gelatin and poly(vinyl alcohol) cross linked with GLU, and the characterization of some of their main physical and functional properties. All the films were produced from film-forming solutions (FFS) containing 2 g macromolecules (PVA + gelatin)/100 g FFS, 25 g glycerol/100 g macromolecules, and 4 g GLU (25% solution)/100 g FFS. The FFS were prepared with two concentrations of PVA (20 or 50 g PVA/100 g macromolecules) and two reaction temperatures: 90 or 55 °C, applied for 30 min. The films were obtained after drying (30 °C/24 h) and conditioning at 25 °C and 58% of relative humidity for 7 days, and were then characterized. The results for the color parameters, mechanical properties, phase transitions and infrared spectra showed that some chemical modifications occurred, principally for the gelatin. However, in general, all the characteristics of the films were either typical of films based on blends of these macromolecules without cross linking, or slightly higher. A greater improvement in the properties of this material was probably not observed due to the crystallinity of the PVA, which has a melting point above 90 °C. The presence of microcrystals in the polymer chain probably reduced macromolecular mobility, hindering the reaction. Thus more research is necessary to produce biodegradable films with improved properties.     

Development of moisture‐absorbing and antioxidant active packaging film based on poly(vinyl alcohol) incorporated with green tea extract and its effect on the quality of dried eel

Active packaging film with functions of moisture‐absorbing and antioxidant activity was developed based on poly(vinyl alcohol) (PVA) incorporated with green tea extract (GTE). The effects of GTE concentrations of 0, 0.5, 1, 1.5, and 2% on the physical, structural, and antioxidant properties of PVA films were investigated. The PVA film containing 2% GTE had lower moisture absorbing efficiency relatively and better antioxidant activity through DPPH radical‐scavenging ability experiment. A packaging system of GTE‐incorporated PVA films was applied to package dried eel and quality of dried eel was evaluated during storage. The result showed that dried eel packed with GTE‐incorporated PVA films showed lower weight change, peroxide value and TBARS value during storage than that packed without PVA films or with PVA films but no GTE. The PVA film containing 2% GTE showed the best quality protective effectiveness to prevent the dried eel from absorbing moisture and oxidizing of lipid.

Practical applications

Poly(vinyl alcohol) (PVA) is a synthetic polymer that is widely used in packaging applications because of its excellent film forming, biodegradability, good mechanical, and gas barrier properties. The present study evidenced that the PVA films incorporated with GTE showed good quality protective effectiveness to prevent the dried eel packed with these films from absorbing moisture and oxidizing of lipid. This active packaging film could be used as inner layer or intermediate layer in the composite packaging film system to improve the storage quality of moisture‐sensitive and high‐fat food. Based on this concept, the moisture‐absorbing agents and antioxidant can be incorporated into the packaging structures to develop an active multifunctional food packaging material potentially to remove or reduce moisture inside the food packaging system instead of desiccants and preservative added in the food.     

壳聚糖明胶可食用复合膜的制备与抗菌性能研究

以壳聚糖和明胶为复合膜骨架材料,通过加入0.3%(体积比)甘油增塑剂,制备具有显著抗菌性能的可食用复合膜。以较高的抗拉强度、较大的断裂伸长率、较低的水蒸气透过系数为主要性能指标,对成膜骨架材料壳聚糖和明胶的配比进行优化。研究结果表明,当壳聚糖浓度为1.5%、明胶浓度为1.25%时,以6∶4的体积比混合,制备获得机械性能良好(抗拉强度为13.24 MPa,断裂伸长率为112.45%),水蒸气透过系数较低(0.4032 mg·mm·kPa-1·h-1·m-2)的最优化复合膜。通过红外光谱、X射线衍射、扫描电镜等手段对复合膜进行表征。结果表明,与壳聚糖膜和明胶膜相比,复合膜的内部分子之间有较强的氢键和分子间作用力,膜内部致密且水蒸气不易通过,同时复合膜液对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌均具有显著的抑制效果。     

Characterization of edible film fabricated with channel catfish (Ictalurus punctatus) gelatin extract using selected pretreatment methods

ABSTRACT:  Farm-raised catfish are important to the economy of the southeastern states in the United States, and catfish processing produces about 55% of by-products for inexpensive sale. Therefore, the utilization of catfish by-products is of great interest to the catfish industry. The objectives of this research were to determine the optimum pretreatment method to extract catfish gelatin for edible film application, and to characterize physical, mechanical, and barrier properties of edible films fabricated with catfish skin gelatin. Catfish skins obtained from a local plant were treated with 6 selected pretreatment methods. The main extraction was performed with deionized water at 50 °C after pretreatment. The gelatin yield was calculated and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to characterize molecular weight (MW) profile. Color, tensile strength (TS), elongation, and water barrier property were determined to characterize the fabricated catfish gelatin films. From the results of gelatin yield, color, SDS-PAGE, as well as mechanical and barrier properties of the film, the pretreatment method with 0.25 M NaOH and 0.09 M acetic acid, followed by extraction at 50 °C for 3 h, was determined as the optimum extraction method. The catfish gelatin exhibited higher MW fractions than commercial mammalian gelatin. The catfish gelatin extracts possessed film-forming properties determined by TS, elongation, and water vapor permeability (WVP) comparable to those of commercial mammalian gelatin. The selected formula for catfish gelatin film was determined as 1% gelatin and 20% glycerol, resulting in greatest TS and lowest WVP.     

Application of soymilk skin as sausage wrapping for improving lipid oxidation

Yuba, the soymilk skin, was developed as edible films for sausage. Yuba (Y) were prepared with added pine-needle extract (YP) and employed to wrap sausage. Physical and mechanical properties and lipid oxidation of sausages were compared to sausages made with commercial collagen casing (C). Y films showed better transparency, oxygen-barrier properties, and UV-light barrier properties than C films (p < .05). Particularly, the addition of pine-needle extract increased DPPH activities from 31 to 48% and total phenol content from 7.52 to 14.64 mg gallic acid/g. Regarding application for sausage wrapping, Y (2.35%) and YP (2.66%) wrapped sausages with better protection against water loss during cooking compared to sausages made from C (5.84%). Especially, YP (3.57 MDA mg/kg) showed better protection against lipid oxidation for sausages than Y (4 MDA mg/kg) and C (4.62 MDA mg/kg) on day 6 after refrigerated storage. Yuba films could be employed as potential alternatives to gelatin films for manufacturing sausages.     

海藻酸钠对鱼皮明胶膜理化特性的影响

采用罗非鱼皮明胶与海藻酸钠混合制备可食性复合膜,研究海藻酸钠含量对复合膜理化性质的影响。结果显示：单一罗非鱼皮明胶具有良好的成膜能力,但是机械性能差,将海藻酸钠添加到明胶膜中得到的复合膜抗拉强度和断裂伸长率有明显改善,海藻酸钠添加量在40%时,抗拉强度达最大值6.6?MPa,相对于纯明胶膜（5.5?MPa）和纯海藻酸钠膜（4.6?MPa）分别增加20%和43%,断裂伸长率也在此时达到最大值120%,比纯明胶膜（64%）和纯海藻酸钠膜（88%）分别增加87.5%和26.7%。海藻酸钠水溶性和吸湿率分别高达100%和48.7%,经共混后复合膜的水溶性降低至55%以下,吸湿率介于25%～40%之间,有较大的改善。流变学特性和X射线衍射分析结果表明：明胶和海藻酸钠具有良好的相容性,二者共混可制得性质稳定的复合膜,海藻酸钠与明胶的复合膜液为非牛顿流体,黏度和增稠能力较单一明胶膜有所增加。     

高抗菌性聚乙烯醇/Ag@MOF食品包装膜的制备与表征

为分析银基金属有机框架(Ag@MOF)用于食品包装的可行性,采用流延法制备四种不同的聚乙烯醇(PVA)基食品包装膜(PVA/Ag@MOF、PVA/H₂PYDC、PVA/Ag、PVA),并研究它们的力学性能、热力学性能、水阻隔性、抗菌性、细胞毒性等。结果表明,与PVA、PVA/H₂PYDC膜相比,Ag@MOF的加入改善了薄膜的力学性能,使薄膜最大拉伸强度提高到36.21 MPa。与PVA、PVA/H₂PYDC、PVA/AgNPs膜相比,Ag@MOF的加入增强了膜的热稳定性。与PVA、PVA/H₂PYDC膜相比,AgNPs和Ag@MOF的刚性结构防止了水的扩散,提高了阻水性能。PVA/Ag@MOF膜对金黄色葡萄球菌和大肠杆菌的抗菌活性也很好,其抗菌活性远大于AgNPs和H₂PYDC复合膜,且具有较低的细胞毒性。因此,PVA/Ag@MOF薄膜是一种很有前景的食品包装材料,可以减少环境微生物对食品的干扰且细胞毒性较低,能够有效提高食品的安全性和储存周期。