乳清蛋白可食用膜抑菌性、溶解性的研究

主要研究了Nisin、纳塔霉素和溶菌酶不同组合添加下乳清蛋白可食用膜的抑菌性和溶解性,结果表明:随着抑菌剂浓度的增加,膜的抑菌效果增强,不同抑菌剂组合下膜的抑菌效果不同,0.35%Nisin和0.08%溶菌酶组合下抑菌效果更好。在酸性环境中,当添加0.03%溶菌酶和0.25%纳塔霉素时,可有效降低膜的溶解性;在中性环境中,各组膜的溶解性几乎相当,在碱性环境中,大部分膜的溶解性要低于其在酸性环境中。     

乳清蛋白可食膜的研究进展

论述了乳清蛋白组成及其功能特性,乳清蛋白可食膜的成膜机理、主要性能及其影响因素和应用。综述了国内外乳清蛋白可食膜的研究进展,提出了乳清蛋白可食膜研究中存在的问题和未来发展趋势。     

TG酶和羟丙基甲基纤维素改善乳清蛋白可食膜性能

以乳清浓缩蛋白(WPC)为基料,通过添加羟丙基甲基纤维素(HPMC,添加量为蛋白质量的5%~25%)和转谷氨酰胺酶(TG酶)对膜的性能进行改良,研究HPMC的添加量和转谷氨酰胺酶的交联作用对复合膜性能的影响。结果表明:HPMC能显著提高蛋白膜的抗拉强度,降低复合膜的断裂伸长率(p<0.05),TG酶能有效改善乳清蛋白-羟丙基甲基纤维素复合膜的柔韧性。当HPMC的添加量为乳清蛋白的20%时,复合膜的抗拉强度较好,表观光滑平整。制备WPC-HPMC复合膜进行奶茶粉、方便面调料包、油包,苏打饼干的初步包装实验,研究了包装产品在储藏12 d期间质量变化情况。结论:乳清蛋白-羟丙基甲基纤维素复合膜具有一定包装应用潜能。     

不同方法处理花生分离蛋白成膜液对膜性能的影响

采用加热处理、超声波处理和微波处理对可食性花生分离蛋白成膜液进行处理,观察不同处理对所制得的蛋白膜的机械性能、阻湿性能和透光性能的影响。结果表明:采用75℃热处理30 min、功率1 000 W超声波处理3 min和功率500 W微波处理2 min,都能够显著增加膜的抗拉强度和透光性;通过热变性处理和超声波处理能够提高膜的阻湿性能,而微波处理对膜的阻湿性能影响较小。     

Effect of temperature,pH and film thickness on nisin release from antimicrobial whey protein isolate edible films

BACKGROUND: An active packaging film based on whey protein isolate (WPI) was developed by incorporating nisin to promote microbial food safety. The effect of temperature and pH on the release of nisin from edible films of different thickness was investigated. The film mechanical properties and inhibitory effect were also evaluated. RESULTS: Nisin release was significantly favoured by low pH, with the highest release after 24 h (1325 IU), which was not significantly affected by temperature (5 or 10 °C). Thickness significantly affected film elongation, with thicker films showing the highest elongation (54.3 ± 2.7%). Water vapour permeability (0.15 ± 0.4 g mm m^?2 kPa^?1 h^?1) and elastic modulus were not significantly affected by thickness. The highest nisin effective diffusivity (5.88 × 10^?14 m² s^?1) was obtained using a solution at pH 4, 112 µm film thickness and a temperature of 5 °C. More than four log cycles of Brochotrix thermosphacta were reduced from the surface of a ham sample after 8 days of incubation at 4 °C by the active WPI film containing 473 IU cm^?2 nisin. CONCLUSION: Nisin diffusivity from WPI edible films was favoured at lower pH and film thickness. This active packaging film may be used to preserve the quality and safety of meat products. Copyright © 2009 Society of Chemical Industry     

几种多糖和交联剂对可食性大豆分离蛋白膜性能的影响

为了提高可食性大豆分离蛋白膜的性能,研究了多糖和交联剂对可食性膜性能的影响。结果表明,在大豆分离蛋白成膜液中添加0.5%(W/V)的果胶能有效增加膜的机械强度,添加0.1%(W/V)的葡萄糖能有效降低膜对水蒸气、氧气的透性。因此,果胶和葡萄糖对其性能的改善效果较佳,果胶和葡萄糖能改善大豆分离蛋白成膜特性的可能机理是因为它们增加了蛋白分子之间的交联。     

多糖和交联剂在制备可食性大豆分离蛋白膜中的互作效应研究

为了提高可食性大豆分离蛋白膜的性能 ,研究了多糖与交联剂混合使用对可食性膜性能的影响。结果表明 ,在大豆分离蛋白成膜液中添加 0 .5 % (W/V)的果胶和 0 .1% (W/V)的葡萄糖能有效增加膜的机械强度 ,降低膜对水蒸汽、氧气的透性。因此 ,果胶 -葡萄糖的组合对膜各性能的改善效果较佳。果胶 -葡萄糖能改善大豆分离蛋白成膜特性的可能机理是因为它们增加了蛋白分子之间的交联。     

Starch–methylcellulose–whey protein film properties

Four % (wt/wt) aqueous solutions were prepared at corn starch:methylcellulose:whey protein isolate (CS:MC:WPI) ratios of 2:2:2, 1:2:3, 2:1:3, 2:2:0, 1:2:0 and 2:1:0. Glycerol (gly) was used as a plasticiser at CS–MC–WPI:gly ratios of 2:1, 2.5:1 and 3:1. CS–MC–WPI blend films were stronger than CS–WPI films and had lower oxygen permeability (OP) than MC–WPI films. The highest tensile strength (TS) of blend films was 8.01 ± 3.41 MPa, at CS:MC:WPI ratio of 2:2:0 and CS–MC–WPI:gly ratio of 3:1. Lowest OP value was 45.05 ± 7.24 cm³ μm m^?2 per day kPa^?1, at CS:MC:WPI ratio of 2:2:2 and CS–MC–WPI:gly ratio of 3:1. OP values were predictable based on relative amounts of components. However, TS and elastic modulus properties of the CS–MC–WPI blend films did not reflect the relative amounts of the components. All of CS–MC–WPI films were translucent indicating some degree of immiscibility among the CS, MC and WPI. These results indicate the influence of complex molecular interactions among the components.     

超声辐射对大豆分离蛋白膜性能的影响

研究了超声辐射在频率为20kHz,功率为800W条件下,不同处理时间对大豆分离蛋白膜性能的影响。结果表明,超声辐射对膜性能有明显的改善作用。经超声辐射处理2min可以显著提高膜的抗拉强度,相对于对照样提高了64.08%(P≤0.05);同时也明显降低了膜的水蒸汽透过系数,相对于对照样降低了25.70%(P≤0.05)。经超声处理后的膜机械强度和阻湿性能均得到了提高,同时具有均匀透明的外观。     

Physical properties of whey protein coating solutions and films containing antioxidants

ABSTRACT:  Antioxidants (ascorbyl palmitate and α-tocopherol) were incorporated into 10% (w/w) whey protein isolate (WPI) coating solution containing 6.67% (w/w) glycerol (WPI:glycerol = 6:4). Before incorporation, the antioxidants were mixed using either powder blending (Process 1) or ethanol solvent-mixing (Process 2). After the antioxidant mixtures were incorporated into heat-denatured WPI solution, viscosity and turbidity of the WPI solutions were determined. The WPI solutions were dried on a flat surface to produce WPI films. The WPI films were examined to determine transparency and oxygen-barrier properties (permeability, diffusivity, and solubility). WPI solution containing antioxidants produced by Process 1 and Process 2 did not show any difference in viscosity and turbidity, but viscosity was greater for the WPI solution with rather than without antioxidants. WPI films produced by Process 2 were more transparent than the films produced by Process 1. Oxygen permeability of Process 1 film was lower than Process 2 film. However, both the diffusivity and solubility of oxygen were statistically the same in Process 1 and Process 2 films. Both control WPI films and antioxidant-containing WPI films had very low oxygen solubility, comparable to polyethylene terephthalate films. Permeability of antioxidant-incorporated films was not enhanced compared to control WPI films.     

均匀试验法优化褐藻胶-乳清分离蛋白可食性膜的工艺

目的制备褐藻胶-乳清分离蛋白可食性膜幵对其工艺条件迚行优化。方法以褐藻胶(sodium alginate,SA)和乳清分离蛋白(whey protein isolate,WPI)为主要原料,甘油为增塑剂制得可食性膜。以溶胶温度、溶胶时间、SA和WPI浓度、钙化时间、钙离子浓度、甘油浓度、超声时间为因素迚行均匀试验,考察指标为溶胶黏度、膜的厚度、透光率、拉伸强度。结果可食性膜性能受WPI浓度、溶胶温度、溶胶时间、钙化时间、超声时间的影响较大,基本不受SA浓度、钙离子浓度和甘油浓度影响,所确定的最佳配比及工艺条件为:SA浓度1.1%、WPI浓度5.5%、溶胶温度65℃、溶胶时间105 min、钙化时间12 min,钙离子浓度1.1%、甘油浓度3.4%和超声时间30min。结论该工艺条件下制备的褐藻胶-乳清分离蛋白可食性膜性能较好,需迚一步验证SA浓度、钙离子浓度和甘油浓度的影响。     

提高多糖类可食性膜机械性能的研究进展

多糖类可食性膜的机械强度强于蛋白类可食性膜,但是还不足以应用到食品包装中。影响多糖类可食性膜机械性能的主要因素有成膜原料中各组分性质、制膜工艺以及贮藏条件等。可通过添加增塑剂、交联剂和改进成膜工艺,来提高多糖类可食性膜的机械性能。     

Ultrasound‐induced changes in physical and functional properties of whey proteins

Use of high‐intensity ultrasound to modify certain functional properties of whey proteins is an alternative to traditional method in food industry. Whey protein isolate (WPI) solutions were treated with an ultrasound probe (20 kHz) at different intensities (20% or 30% amplitude) and durations (10 or 20 min). Results showed that ultrasound treatment changed physical and several functional properties of whey proteins including decreased particle size (from 190.4 nm to 138.0 nm), increased surface hydrophobicity (from 5.13 × 10⁵ to 5.77 × 10⁵), free sulphydryl groups (from 52.64 μmol SH g^?1 to 53.64–58.77 μmol SH g^?1), solubility (from 74.95% to 89.70%), emulsion activity index (from 3.18 m² g^?1 to 3.59–5.32 m² g^?1) and emulsion stability index (from 62.26 min to 71.44–104.83 min), and changed viscosity (from 5.51 mPa.s to 4.81–5.64 mPa.s). Therefore, we conclude that high‐intensity ultrasound can be potentially applied to whey proteins to improve its specific functions during food processing.     

低温储藏条件对大豆分离蛋白膜理化特性的影响

以大豆分离蛋白为原料制得可食性膜,研究在不同低温储藏条件下其功能特性,包括机械性能和阻隔性能的变化。结果显示:随冷藏温度的升高,其功能特性变化较为缓慢。而随冻藏温度的降低,断裂延伸率下降尤为明显,抗拉强度和脂质阻隔能力变化趋势次之,水蒸气透过率升高缓慢。冷藏时间与断裂延伸率呈显著正相关(p<0.05)。冷藏时间与水蒸气透过率和油脂渗透系数均呈极显著正相关(p<0.01)。冻藏时间与水蒸气透过率和油脂渗透系数呈显著正相关(p<0.05)和极显著正相关(p<0.01)。     

Impact of whey protein isolates and concentrates on the formation of protein nanoparticles‐stabilised Pickering emulsions

Whey protein nanoparticles (NPs) were prepared by heat‐induced method. The influences of whey protein isolates (WPIs) and concentrates (WPCs) on the formation of NPs were first investigated. Then Pickering emulsions were produced by protein NPs and their properties were evaluated. After heat treatment, WPC NPs showed larger particle size, higher stability against NaCl, lower negative charge and contact angle between air and water. Dispersions of WPC NPs appeared as higher turbidity and viscosity than those of WPI NPs. The interfacial tension of WPC NPs (~7.9 mN/m at 3 wt% NPs) was greatly lower than that of WPI NPs (~12.1 mN/m at 3 wt% NPs). WPC NPs‐stabilised emulsions had smaller particle size and were more homogeneous than WPI NPs‐stabilised emulsions. WPC NPs‐stabilised emulsions had higher stability against NaCl, pH and coalescence during storage.     

可食性大豆分离蛋白膜制备与性质

为探索新型生物膜材料的制备,以大豆分离蛋白为基本材料,探究大豆分离蛋白(SPI)、增塑剂(甘油)、还原剂(Na_2SO_3)、乙醇等添加量和处理温度、成膜液pH、成膜介质等条件对膜的完整率、厚度、透光率、水溶率、水蒸气透过系数、透油性等性质的影响。当SPI浓度在2%~6%时,随着添加量的增加,成膜变得容易,但是膜的厚度增加、水蒸气透过系数和透油系数变大、色泽变深。甘油添加量在2%以下可以改善膜的柔韧性,同时降低膜的透气性能和透油性。添加5%的乙醇也可以降低膜的透气性和透油性。添加0.1%的Na_2SO_3可以改善膜的色泽,同时降低膜的透油性。适当提高处理温度和溶液pH可以降低膜的透气性和透油性。     

可食性花生蛋白膜研究进展

花生蛋白膜是一种以花生分离蛋白为原料的天然高分子材料,具有可食用、可降解、可再生、原料价格低廉等优点。对可食性花生蛋白膜的制备(湿法、干法)、蛋白膜性能(机械性能、热性质和耐水性)、花生蛋白改性(物理、化学、酶法)对蛋白膜性能的影响、蛋白膜结构(化学键、微观表面结构)以及应用进行综述,同时指出目前该研究领域中存在的问题,并对未来的研究重点进行展望,为可食性花生蛋白膜的进一步开发利用提供参考。     

甘油含量对大豆蛋白膜功能性质的影响

大豆蛋白膜是一种可降解、可食用和可再生的新型包装材料,但是其机械性能尚不能满足日常使用的需求。研究甘油含量对可食性大豆蛋白膜功能性质的影响,结果显示随着甘油含量的增加,大豆蛋白膜抗张强度下降,而断裂延伸率、水蒸气透过率和氧气透过率升高。当甘油添加量为大豆蛋白的30%时,大豆蛋白膜具有较好的机械性能。因此,甘油含量是影响大豆蛋白膜机械性能的主要因素之一。