泠冻保藏对大豆分离蛋白膜机械性能的影响

用大豆分离蛋白(SPI)制备可食性包装膜时，在成膜溶液中分别添加单甘酯、葡萄糖制成大豆分离蛋白膜，将其分别在室温下(RH65％)保存2d以上和在冷冻保藏7d后测定机械性能，发现添加这些物质后制得的膜的机械性能均受到影响：含单甘酯的膜的抗拉强度(TS)增加超过25％，断裂伸长率(E)变化不大；而含葡萄糖的膜TS增加了35％以上，E增加了55％以上。冷冻对各种SPI膜的机械性能有不同影响，对含葡萄糖的SPI膜的抗拉强度影响很大，TS下降达50％，对其他SPI膜的影响不太大，这意味着不含葡萄糖的SPI膜可用于冷冻食品包装。     

模糊综合评判用于大豆分离蛋白膜制备工艺的优化

为分析大豆分离蛋白(SPI)膜机械性能的影响因素及最优参数的选择,以SPI溶液质量分数、甘油添加量(占SPI质量)、成膜温度和膜液pH为实验因素,进行了单因素实验和正交实验。采用方差分析和直观分析初步确定了影响膜机械性能的主要因素及工艺参数;采用模糊综合评判方法对抗拉强度(TS)和断裂伸长率(EAB)进行综合评判,进而优化各影响因素。结果表明:甘油添加量对膜的机械性能影响最大;在TS和EAB这两个评判指标的权重向量为0.5∶0.5时,最优工艺参数为SPI溶液质量分数4%、甘油添加量20%、成膜温度65℃、膜液pH 10,此时大豆分离蛋白膜的TS和EAB可达5.41 MPa和186.36%。模糊综合评判在优化大豆分离蛋白膜制备工艺方面能起到一定的指导作用。     

还原剂影响可食性大豆分离蛋白膜性能的研究

研究了还原剂对可食性大豆分离蛋白 (SPI)膜性能的影响。结果表明 ,还原剂可明显提高SPI膜的抗拉强度 (TS) ,降低水蒸气迁移系数 (WVP) ,但伸长率 (E)有所下降。添加还原剂的SPI膜在 pH 7时机械强度和阻隔性最好 ,其中添加半胱氨酸的SPI膜 TS最大 ,为14.4 8MPa ,WVP最小 ,为 4 .6 1g·mm/m2 ·d·kPa     

热处理和碱处理对可食性大豆分离蛋白膜性能的影响

研究了热处理和碱处理对可食性大豆分离蛋白(SPI)膜性能的影响。对成膜液进行适当的加热和调节pH可以提高SPI膜的抗拉强度(TS)和伸长率(E),降低水蒸气透过系数(WVP)。调节成膜液的pH到9,在70℃加热20min,所得到的膜机械性能和阻湿性能最好。     

pH和AOT添加物对大豆分离蛋白基可降解膜机械性能影响

运用响应面分析法分析pH和AOT(琥珀酸二异辛酯磺酸钠)添加物对大豆分离蛋白(SPI)基生物可降解膜机械性质影响,确定影响该种膜机械性能最优工艺参数;测试膜机械性质,包括抗拉强度、穿刺强度、断裂伸长率;分析结果表明,在pH为8.95,AOT添加量为13.00%(w/w)时,膜综合机械性能达到最优。     

成膜介质和还原剂对大豆分离蛋白膜性能的影响

研究了成膜介质和还原剂对大豆分离蛋白膜(SPI)性能的影响。结果表明,大豆分离蛋白在自制玻璃板上成膜效果最好;亚硫酸钠可明显提高SPI膜的抗拉强度,对透气度和透光率影响不显著;添加0.1%亚硫酸钠的SPI膜抗拉强度最大,超过0.1%,抗拉强度下降明显。     

pH和AOT添加物对大豆分离蛋白基生物可降解膜机械性能的影响

运用响应面分析法分析了pH和AOT(琥珀酸二异辛酯磺酸钠)添加物对大豆分离蛋白(SPI)基生物可降解膜机械性质的影响,确定了影响该种膜机械性能的最优工艺参数。测试的膜的机械性质包括抗拉强度、穿刺强度、断裂伸长率。分析结果表明,在pH为8.795,AOT的添加量为13.00%时,膜的综合机械性能达到最优。     

还原剂对花生分离蛋白膜的保藏性能影响研究

研究了还原剂对花生分离蛋白膜性能的影响。结果表明,还原剂可明显提高花生分离蛋白(PPI)膜的抗拉强度(TS),降低水蒸气迁移率(WVTR),添加还原剂亚硫酸钠比添加葡萄糖效果更好。添加0.1%亚硫酸钠的PPI膜抗拉强度最大,超过0.1%抗拉强度则明显下降。     

可食性SPI/HPC膜的性能

研究了不同浓度的羟丙基纤维素(HPC)对大豆分离蛋白(SPI)膜性能的影响.结果表明,HPC的添加浓度对SPI膜的性能有显著影响.在SPI膜中添加HPC后,膜的抗拉强度明显增加,透光率降低,表面疏水性增大.这表明HPC和SPI分子之间发生了强的相互作用,进一步影响膜的性能.     

不同增塑剂对大豆蛋白包装薄膜机械性能稳定性的影响

大豆蛋白膜是以大豆分离蛋白（soybean protein isolate,SPI）为主料,添加适量增塑剂形成具有一定机 械性能的包装薄膜,但其在贮藏过程中机械性能的不稳定是制约其在实际中应用的主要因素。因此本实验选取甘 油、山梨醇、油酸3 种增塑剂制备SPI膜,以贮藏期间抗拉强度、断裂延伸率、水蒸气透过率、水溶失率的变化为 评价指标,探讨添加不同增塑剂的SPI膜在贮藏期间机械性能变化规律。结果表明,以甘油、山梨醇和油酸组合 （2∶1∶1,m/m）作为增塑剂制备SPI膜时,SPI膜机械性能稳定性最佳,与空白组（单独由甘油增塑的SPI膜）相 比,抗拉强度稳定性提高了64%,断裂延伸率稳定性提高了65%,水蒸气透过率稳定性提高了27%,对水的稳定性 提高了20%。本实验可为SPI包装薄膜在实际中更广泛的应用提供一定的理论依据。     

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)。     

冷藏、冻藏时间对玉米醇溶蛋白膜影响

不同冷藏、冻藏时间对玉米醇溶蛋白膜特性有一定影响,蛋白膜机械特性、平衡水分含量和水蒸汽透过率随冷藏、冻藏时间变化而变化。随着冷藏、冻藏时间不断增加,蛋白膜抗拉强度和延伸率都呈下降趋势；但冷藏条件下蛋白膜机械特性较冻藏条件下为好；蛋白膜平衡水分含量随时间增加而降低；蛋白膜水蒸汽透过率随冷藏、冻藏时间增加而上升。     

Properties of cast films of vicilin-rich protein isolates from Phaseolus legumes: Influence of heat curing

The mechanical, hydrophobic and thermal properties of cast films of vicilin-rich protein isolates from three Phaseolus legumes were investigated and compared to that of soy protein isolate (SPI). The influence of heat curing at 85 °C on the properties of these films was characterized. The films of vicilin-rich protein isolates exhibited much less mechanical strength (TS) and elongation at break (EB) and similar film surface hydrophobicity, as compared with those of the SPI film. The heating remarkably improved the TS of these films, and the extent of the improvement much higher than that of the SPI film, while the EB was only slightly affected. The thermal properties of these protein isolate films were variable, and much distinctly affected by the heating of the films, to a various extent, depending on the type of protein isolates. Protein solubility analyses indicated strengthened hydrogen and hydrophobic bondings of these films by the heating. The results suggest that those vicilin-rich protein isolates have good potential to form cast films with mechanical strength comparable to that of SPI film.     

Mechanical and barrier properties of biodegradable soy protein isolate-based films coated with polylactic acid

Polylactic acid (PLA)-coated soy protein isolate (SPI) films were prepared by dipping SPI film into PLA solution. The effects of coating on improvements in mechanical and water barrier properties of the film were tested by measuring selected film properties such as tensile strength (TS), elongation at break (E), water vapor permeability (WVP), and water solubility (WS). TS of SPI films increased from 2.8±0.3 up to 17.4±2.1 MPa, depending on the PLA concentration of the coating solution, without sacrificing the film's extensibility. In contrast, the extensibility of SPI film coated with solution containing more than 2 g PLA/100 ml solvent, increased. WVP of PLA-coated SPI films decreased from 20 to 60 fold, depending on the concentration of PLA coating solution. Water resistance of SPI films was greatly improved as demonstrated by the dramatic decrease in WS for PLA-coated films. The improvement in water barrier properties was mainly attributed to the hydrophobicity of PLA.     

Effect of glycosylation on the mechanical properties of edible soy protein packaging film

In this paper, we explore the glycosylation conditions (glucomannan content, reaction time, temperature and humidity) to probe the relationship between glycosylation and mechanical properties of soy protein isolate (SPI) film. The mechanical properties were characterized by studying the tensile strength (TS) and elongation at break (EB). Furthermore, degree of glycosylation, free glucomannan content, surface hydrophobicity, sulfhydryl groups content, lysine and arginine content of glycosylation soy protein with different reaction time were investigated to certify the significant effect of glycosylation on mechanical properties of soy protein film. What is more, the comparison of TS and EB, contact angle values and water vapor permeability of glycosylation SPI (GSPI), SPI and mixture of SPI and glucomannan films showed the excellence of GSPI. At the end, the analysis of scanning electron microscope was applied to reveal the effect of glycosylation on the structure of films. These results suggested that glycosylation with glucomannan is an ideal method to enhance the mechanical properties of soy protein isolate film.     

Edible films made from membrane processed soy protein concentrates

Edible films were prepared from membrane processed soy protein concentrate (MSC) at various film forming solution pHs, and their mechanical, barrier, and physical properties were compared with soy protein isolate (SPI) films. As the film solution pH increased from 7 to 10, the resulted MSC films were more transparent, yellowish, and had lower oxygen permeabilities. However, tensile strength (TS), modulus of elasticity (ME) and water vapor permeabilities of MSC films were not affected by film solution pHs. The values of MSC films prepared at pH 7 were not significantly (P>0.05) different from those of SPI films prepared at alkaline solutions (pH 8-10). The uniform TS and ME values of MSC film over the wide film solution pH ranges were attributed to the higher solubility of MSC at pH 7. For the films formed at neutral film solutions (pH 7.0), MSC films showed significantly (P<0.05) higher elongation value, film solubility, and transparency compared to SPI films.     

冻融处理对淀粉膜结构、热稳定性、机械性能及物理性质的影响

本实验分别以天然马铃薯淀粉（potato starch,PS）、改性马铃薯淀粉（包括羟丙基二淀粉磷酸酯（hydroxypropyl distarch phosphate,HDP）、醋酸淀粉（acetate starch,AS）和氧化淀粉（oxidized starch,OS））为基材,通过流延法制备可食用淀粉膜,考察冻融处理对膜物理性质、机械性能、阻隔性能、微观结构和热稳定性的影响。X射线衍射结果表明,马铃薯来源的淀粉颗粒具有典型的B型晶体结构,在成膜过程中淀粉结晶度降低,冻融处理后淀粉膜晶体峰强度明显减弱。扫描电子显微镜观察结果显示,冻融处理破坏了淀粉膜的微观结构,其中PS膜上出现明显裂纹,AS膜上出现蜂窝和层状结构,而HDP和OS淀粉膜具有更完整的形态。热重分析结果表明,随着温度的升高,淀粉膜的热重曲线出现4 个质量损失阶段,分别对应水分散失、甘油挥发、淀粉解聚及淀粉分解,而冻融处理对膜热稳定性影响较小。常温条件下,PS膜具有最佳的机械性能,其拉伸强度为2.29 MPa,断裂伸长率为68.82%。在3 个冻融循环后,淀粉膜的拉伸强度至少增加了2 倍,断裂伸长率普遍降低,而溶解度和水蒸气透过率仅有轻微变化。综合考虑不同淀粉膜微观结构、机械性能、水蒸气透过率及水溶性,HDP膜表现出更好的冻融稳定性,可应用于冷冻低水分食品的保藏。     

Permeability and Mechanical Properties of Cellulose-Based Edible Films

Factors affecting barrier properties [oxygen permeability (OP) and water vapor permeability (WVP)] and mechanical properties [tensile strength (TS) and elongation (E)] were investigated for methyl cellulose (MC) and hydroxypropyl cellulose (HPC) films. OP, WVP and TS of MC and HPC films increased as the molecular weight (MW) of the cellulose increased. E of MC films increased as MW increased, but E of HPC films was highest for the intermediate MW of 370,000. OP, WVP and TS of MC films were not a function of thickness, but E slowly increased as film thickness increased. OP and WVP of HPC films were not relatable to film thickness, but TS and E of HPC films slowly increased as film thickness increased. TS decreased and E increased for both film types as concentration of plasticizers was increased. Plasticizers enhanced or retarded OP and WVP of cellulose-based films, depending on their concentrations.