迷迭香大豆分离蛋白膜的制备及其性能

以大豆分离蛋白为基质,通过添加迷迭香来制备抗氧化薄膜,研究迷迭香抗氧化剂的添加对膜理化性质和抗氧化性能的影响。结果表明,迷迭香和大豆分离蛋白制备的活性蛋白膜材料具有光滑透明的外观和优秀的机械性能,其拉伸强度超过同厚度的低密度聚乙烯材料。迷迭香含量的不同导致其与蛋白基材料间的相互作用力不同,从而使活性蛋白膜出现不同的结构,其中迷迭香质量浓度为0.25 g/L的活性蛋白膜所具有疏松结构,为迷迭香与自由基的反应提供了便利,其对ABTS+自由基的抑制率大于其他活性蛋白膜,呈现出最佳的抗氧化性能。     

明胶/壳聚糖/迷迭香复合膜的制备与表征

为开发新型具有抗氧化活性的包装材料,以壳聚糖、鱼皮明胶为复合膜基质材料,研究添加迷迭香提取物对复合膜物理性质、微观结构及抗氧化性能的影响。结果表明,添加0.1%迷迭香提取物显著(p<0.05)提高了复合膜的抗氧化性能,将膜的DPPH自由基清除率由15%以下提高到60%以上。迷迭香提取物的添加影响了膜的结构与理化性质。其中,膜的热变性温度由130.97 ℃升至167.52 ℃,同时水溶解性下降了12.62%,但对膜的力学性质没有显著影响。红外光谱显示添加迷迭香提取物影响了O-H键的弯曲和伸缩振动,干扰了复合膜体间的氢键相互作用。研究结果表明,添加0.1%迷迭香提取物既能提高明胶/壳聚糖复合膜的抗氧化能力,又可使复合膜的热稳定性提高,明胶/壳聚糖/迷迭香复合膜活性包装材料具有良好的应用前景。     

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     

含迷迭香的蛋白基薄膜对高氧气调包装生鲜猪肉的护色及抗氧化作用

以不同质量浓度迷迭香与大豆分离蛋白复合制备活性蛋白膜,并将该蛋白膜用于高氧气调下生鲜猪肉的护色保鲜。分析猪肉贮藏期间CIE a*值、正铁肌红蛋白、硫代巴比妥酸反应（thiobarbituric acid reactive substances,TBARS）值、蛋白质羰基及肉品硬度的变化情况。结果表明：肉样表面喷洒0.05 g/100 mL迷迭香提取物有效抑制了高氧气调包装肉品的脂类氧化和贮藏后期的颜色劣变。而蛋白膜加入不同质量浓度迷迭香对高氧气调包装的猪肉表现出不同的抗氧化活性。纯蛋白膜和0.025 g/100 mL迷迭香包装组对猪肉没有表现出护色作用,但对猪肉贮藏期间脂类和蛋白质的氧化起到了一定的抑制作用;0.1、0.2 g/100 mL迷迭香包装组有效延缓了猪肉a*值的下降和正铁肌红蛋白、TBARS值的生成,且其对猪肉的护色效果好于迷迭香直接喷洒处理,但无法抑制蛋白质羰基的形成。而0.05 g/100 mL迷迭香包装组在整个贮藏期间对猪肉颜色、脂类、蛋白质等的抗氧化效果均好于迷迭香直接喷洒处理,且基本维持了肉品贮藏期间的硬度,这表明蛋白膜对迷迭香的包埋显著提高了迷迭香对高氧气调下猪肉的抗氧化活性。     

阳离子对SPI膜性能的影响

本论文采用湿法工艺制备可食性大豆分离蛋白膜(SPI),通过添加Na 、Zn2 、Fe3 ,考察了阳离子价态对SPI膜性能的影响。结果显示,阳离子价态对SPI膜的透光率(TP)没有影响;使SPI膜的水蒸气透过系数(WVP)增加;添加有0.5%(w/w SPI)的Fe3 的SPI膜的整体性能比较好。     

魔芋葡甘聚糖-甲基纤维素可食膜的制备及其性能研究

利用魔芋葡甘聚糖和甲基纤维素制备可食膜,研究甲基纤维素添加量、甘油添加量、均质时间和干燥温度对可食膜性能的影响。首先进行单因素实验,得到了各个变量甲基纤维添加量、甘油添加量、均质时间、干燥温度对可食膜水蒸气透过系数(WVP)、断裂伸长率(E)、抗拉强度(TS)的影响。在单因素的基础上确定了各变量的范围,选择WVP和E作为响应值,进行了响应面优化实验。研究结果:在最优水平下,甘油添加量0.963%(V/V),甲基纤维素添加量0.238%(W/V),干燥温度59.6℃,均质时间8.91min,WVP可达到8.4511×10-10g/m·s·Pa;甘油添加量0.985%(V/V),均质时间7.68min,干燥温度40℃,甲基纤维素添加量0.363%(W/V),E可达到130.25%。     

水分散型迷迭香抗氧化剂的制备及其在猪肉糜中的抗氧化效果的评价

本文建立了同时检测迷迭香提取物中五种成分(鼠尾草酚、鼠尾草酸、迷迭香酸、齐墩果酸和熊果酸)含量的高效液相色谱方法,优化了水分散型迷迭香抗氧化剂的制备条件,并将其添加到猪肉糜中,测定其抗氧化效果。结果表明,水分散型迷迭香抗氧化剂的最优制备条件是:聚甘油脂肪酸酯与吐温80的复配比例为1:5(m/m),油水相比例为4:6(m/m),乳化转数2800 r/min,该条件下制备的抗氧化剂粒径为318.83 nm。猪肉糜中添加0.03%的水分散型迷迭香抗氧化剂,能够显著(P<0.05)减缓L*和a*的下降,抑制菌落总数的增加,延缓氧化和腐败变质,货架期相比未添加组可延长4 d。     

阴离子对SPI膜性能的影响

本论文采用湿法工艺制备可食性大豆分离蛋白膜(SPI),通过添加氟离子.硫代硫酸根离子、碳酸根离子.焦磷酸根离子,磷酸根离子,考察了阴离子价态对SPI膜性能的影响.结果显示,阴离子价态对SPI膜的透光率没有影响;使SPI膜的WVP增加;添加有2.0%(w/wSPI)的CO32-的SPI膜的整体性比较好.     

迷迭香天然抗氧化剂的应用研究

以核桃油为实验基油,研究了迷迭香天然抗氧化剂的应用。通过抗氧化实验、储藏实验和烹调实验,比较了迷迭香抗氧化剂和TBHQ的抗氧化效果。结果表明,迷迭香抗氧化剂具有较佳的抗氧化效果,在核桃油中随着迷迭香抗氧化剂添加量的增大抗氧化效果依次增强,0.02%迷迭香抗氧化剂与0.02% TBHQ有相似的抗氧化能力,可对核桃油酸败和反式脂肪酸形成起到延缓作用。     

鱼肉蛋白肽在模拟胃肠消化吸收过程中的抗氧化活性和生物利用度

以鳕鱼鱼肉蛋白肽为研究对象,构建体外胃肠消化模型和Caco-2细胞吸收模型,模拟连续的胃肠消化、吸收过程,测定抗氧化活性和生物利用度。结果显示:在模拟胃肠消化过程中,鱼肉蛋白肽的水溶性维生素E抗氧化能力(TEAC)变化不显著(p0.05),DPPH自由基清除率在胃消化阶段下降而在肠消化阶段升高(p0.05),但低于消化前的水平(p0.05)。在模拟转运2 h过程中,鱼肉蛋白肽吸收产物的肽氮含量逐渐增加,TEAC和氧自由基抗氧化能力(ORAC)显著升高(p0.05)。鱼肉蛋白肽的生物利用度显著高于鱼肉(9.1%),且分子量最小的蛋白肽的生物利用度最高(46.2%)。鱼肉蛋白肽经胃肠消化吸收后,具有一定的抗氧化活性且生物利用度较高,为鳕鱼蛋白肽的开发利用提供了理论依据。     

Development of Active Films From Pectin and Fruit Extracts: Light Protection,Antioxidant Capacity,and Compounds Stability

Pectin films containing fruit extracts were developed and tested in relation to ultraviolet light transmission, phytochemical contents, and antioxidant capacity during 90 d shelf life storage. Aqueous and alcoholic extracts from 5 different fruits (acerola, cashew apple, papaya, pequi, and strawberry) were obtained. Because the alcoholic extracts from acerola, cashew apple, and strawberry presented the highest phytochemical content and antioxidant capacity, they were incorporated into pectin films individually or as a mixture. Incorporation of these extracts into pectin films provided antioxidant capacity while retaining the physical properties. The pectin films containing fruit extract acted as adequate light barrier and prevented photooxidation. Among the prepared films, the pectin film containing acerola extract afforded the highest antioxidant capacity, with a half‐life of 99 d. Overall, the results revealed that incorporation of fruit extracts into pectin films potentially produces antioxidant films and coatings for different food applications.     

Development and characterisation of polylactic acid–gliadin bilayer/trilayer films as carriers of thymol

Biodegradable food packaging promises a more sustainable future. Poly(lactic acid) (PLA) is a promising alternative for petroleum‐derived polymers. However, PLA films suffer from poor barrier properties compared with petroleum‐derived ones. To address this issue, we designed bilayer and sandwich‐architectured trilayer films based on PLA and gliadin. We reported firstly the direct formation of PLA–gliadin bilayer/trilayer films without surface modification on PLA film. The films were compact and uniform, and double/triple layers were combined firmly, preventing delamination. This strategy enhanced mechanical resistance, ductility and moisture barrier of gliadin films and concomitantly enhanced the oxygen barrier for PLA films. Thymol loadings endowed bilayer/trilayer films with antimicrobial activity and antioxidant activity. The antimicrobial activity of the films depended on film types, and gliadin layer presented larger inhibition zone than PLA layer, hinting that the films possessed directional releasing role. This study opens a promising route to fabricate bilayer/trilayer architecture helping to create synergism of the biopolymers.     

Water Vapor Permeability, Mechanical Properties and Antioxidant Effect of Mexican Oregano–Soy Based Edible Films

ABSTRACT:  Water-soluble extracts from Mexican oregano ( Lippia graveolens ) were incorporated into soy protein isolate (SPI) films. Water vapor permeability, mechanical properties, and antioxidant ability were evaluated. All the extracts were capable of scavenging DPPH radicals in a concentration-dependent fashion; the IC₅₀ values were obtained. Oregano extracts were incorporated into SPI films plasticized with sorbitol, glycerol, and glycerol–sorbitol 1:1. The addition of the extracts resulted in an increase in the water vapor permeability values and provided a dark reddish film appearance. Changes in tensile strength as well as elongation values were observed. The oregano SPI films exhibited antioxidant properties in a concentration-dependent fashion.     

肉制品加工中使用的辅料——抗氧化剂

氧化是导致食品品质劣变的一个重要因素,也是影响肉及肉制品品质的一个重要因素,防止食品氧化可以通过向食品中添加抗氧化剂实现,食品抗氧化剂是防止或延缓食品氧化,提高食品稳定性和延长食品储藏期的食品添加剂。本文综述食品抗氧化剂的作用机理,抗氧化剂使用的注意事项及食品中常用的抗氧化剂,并简要介绍抗氧化剂活性的测定及对其发展前景进行展望。     

Assessing and comparing antioxidant activities of lactobacilli strains by using different chemical and cellular antioxidant methods

Some lactobacilli strains had beneficial effects on human beings due to their antioxidant activities. In this study lactobacilli strains stored in our laboratory were screened for potential antioxidant activities by investigating their 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, oxygen radical absorbance capacity, resistance to H₂O₂, and hydroxyl free radical scavenging activity; then the antioxidant activities of the screened strains were evaluated by cellular antioxidant assay and protection for HT-29 cells against H₂O₂ injury assay. The results showed that Lactobacillus plantarum Y44 could scavenge oxygen free radicals, inhibit the production of intracellular reactive oxygen species without creating obvious cytotoxic effects, and protect HT-29 cells against H₂O₂ injury evidenced by the significant decrease of the Bcl-2-associated X protein (Bax)/B-cell lymphoma 2 (Bcl-2) ratio and heat shock protein 70 expression, increase of superoxide dismutase and glutathione peroxidase activities, and decrease of malondialdehyde level of HT-29 cells damaged by H₂O₂. It was speculated that L. plantarum Y44 protect HT-29 cells against oxygen radical injury through scavenging reactive oxygen species and activating intracellular antioxidant enzymes. A significant correlation was observed among the results of the hydroxyl radical scavenging assay, protection assay for HT-29 cells against H₂O₂ injury, and the cellular antioxidant assay. The findings indicated that L. plantarum Y44 could be a probiotic candidate with antioxidant properties and combining several chemical antioxidant methods and antioxidant cellular models could be an effective procedure to screen lactobacilli strains with antioxidant activity.     

果蔬酚类物质抗氧化活性研究

采用基于不同机理的抗氧化方法对果蔬中常见的酚类物质单体,包括黄烷酮、多甲氧基黄酮、黄酮醇、酚酸等活性成分行了较全面的评价。结果显示酚类物质的抗氧化能力与其结构有密切关系。对天然产物或抗氧化剂的抗氧化能力的评价应该采用至少两种机理不同的抗氧化方法进行测试,才能取得较为客观有效的结论。     

HPLC法同时测定五层共挤膜中4种抗氧剂的含量

目的:建立五层共挤膜中抗氧剂1010、抗氧剂330、抗氧剂1076和抗氧剂168的含量测定方法。方法:采用Agilent Eclipse XDB-C18色谱柱(4.6mm×150mm,5μm);流动相为乙腈-四氢呋喃-水[61∶29∶10];紫外检测器,检测波长为280nm;流速为1.5m L/min;进样量为20μL。结果:抗氧剂1010、抗氧剂330、抗氧剂1076和抗氧剂168在2.4μg/m L~480μg/m L范围内线性关系良好,相关系数均大于0.999。4种抗氧剂的回收率在83%~104%之间,RSD最大为3.5%。结论:该方法具有良好的专属性、检测灵敏度、精密度、线性和准确度,可用于五层共挤膜中抗氧剂的质量控制。