大豆蛋白/壳聚糖复合膜的控释特性的研究

采用共混法形成壳聚糖(CS)-大豆蛋白(SPI)复合膜,并将茶碱包埋于其中制备茶碱的定位控释载体。结合红外分析和扫描电镜技术研究复合膜的释放特性和表面形态,其结果表明复合膜中大豆蛋白和壳聚糖之间存在交联作用;这种复合膜在胃肠液均呈溶胀状态,在模拟胃液中溶胀度较低,且在模拟肠液中降解速率较快。复合膜在模拟胃液中的释药速率相对模拟肠液要快,而且随着蛋白含量的增加,复合膜的溶胀度和释放率都随之降低,所有的复合膜对于茶碱的保护能保持至少7 h,因此壳聚糖-大豆蛋白复合膜可以用作控缓载体。     

低温红肠在天然可食性膜包装条件下的货架寿命研究

以壳聚糖、海藻酸钠、大豆分离蛋白为原料制备天然可食性膜,通过测定可食性膜的水溶性、透明度、膜的厚度筛选出贮藏低温肉制品最优的可食性膜,并通过测定不同贮藏期低温红肠的感官评价、细菌总数、脂肪氧化值(TBARS)、H2S等指标研究可食性对低温肉制品货架期的影响,结果表明:低温红肠制品用1组(2%壳聚糖+1%冰乙酸)、2组(...     

采前低聚壳聚糖处理对冬枣果实抗病性的诱导

为提高冬枣抗病性,延长保鲜期,采用采前低聚壳聚糖喷施处理冬枣树,低温贮藏,分析研究了枣果实发病情况及抗病性。结果表明,壳聚糖处理明显降低了发病率和发病指数,集中发病期推迟6d,提高了枣果实中总酚的含量,且显著增加了贮藏前期冬枣的类黄酮含量;显著增加了PPO、POD和PAL的活性,其中POD活性最高可达对照组的4.46倍,PAL活性最高可达对照组的3.19倍。     

单凝聚法制备壳聚糖-艾蒿油微胶囊抗菌剂的研究

探讨了以壳聚糖作壁材、艾蒿油作芯材，采用单凝聚法制备绿色环保型微胶囊织物抗菌剂的工艺条件，研究了w（艾蒿油和壳聚糖）、pH、凝聚温度等因素对微胶囊化的影响，用多媒体显微镜观测了微胶囊颗粒的外观形貌、粒径大小及分布，将所制微胶囊用于棉织物整理并检测了效果确定了用单凝聚法制备壳聚糖-艾蒿油微胶囊的最佳工艺：pH为7．0-7，5，w（艾蒿油和壳聚糖）为1．0％～15％（对反应液质量），50℃，30（交联剂）为2％（对壁材质量）；制备的微胶囊基本呈球体，平均粒径为2～4μm，分布较集中；当w（微胶囊）为1．00％（对整理液质量）时，整理试样对金黄色葡萄球菌和大肠杆菌的抑菌率分别为93．07％和84．33％，但白度稍有降低．     

不同澄清剂对食醋澄清的效果比较

针对食醋的非生物性返浑问题,对不同澄清剂在食醋中的应用进行了比较.研究表明:活性炭负载壳聚糖、蛋白酶、交联聚乙烯吡咯烷酮(PVPP)、皂土负载壳聚糖、7％皂土、1％单宁酸、壳聚糖每升醋液的最佳使用量分剐为5 g,5 g,0.2g,10 g,20 mL,20 mL,0.04g.其中,活性炭负载壳聚糖澄清效果最佳,在25℃的条件下,经过活性炭负载壳聚糖作用的醋液可较长时间保持澄清,澄清时间达到半年左右.     

壳聚糖接枝丙烯酰胺反相胶乳的合成及应用

采用反相乳液聚合技术对壳聚糖和丙烯酰胺进行接枝聚合反应,结果表明,在油相体积与水相体积比为1:1、壳聚糖与丙烯酰胺质量比为1:8、引发剂(CAN)浓度为0．67 mmol/L、反应时间为4h、乳化及反应温度为50℃、乳化剂用量为7%、m_(Span-80):m_(OP-10)=6:4、搅拌速度为1100 r/min的条件下,可以得到稳定的胶乳,将其用作纸张增强剂取得了较好的应用效果。     

Edible coatings for enhancing microbial safety and extending shelf life of hard-boiled eggs

ABSTRACT:  Hard-boiled eggs were coated with chitosan–lysozyme (CL), whey protein isolate (WPI), or Bake sheen (BS), inoculated with Listeria monocytogenes or Salmonella enterica Ser. Enteritidis at 10⁴ CFU/g, and stored for 4 wk at 10 °C. Microbial populations were enumerated weekly. Two nonchallenge studies were also conducted with hard-boiled eggs: coated shell-on eggs packaged in plastic containers or peeled eggs coated and vacuum-packaged. Total plate counts (TPC), coliforms, yeasts, molds, weight loss, pH, and color of eggs were determined during the 10-wk storage at 10 °C. Uncoated eggs served as controls. All the coatings were not effective in inhibiting the growth of L. monocytogenes, but CL coating controlled the growth of S. Enteritidis. At the end of 4-wk storage, the numbers of S. enteritidis on CL-coated eggs were about 4-log₁₀ CFU/g less than that of the controls. Coatings reduced ( P < 0.05) the populations of coliforms and TPC, and completely inhibited mold growth during the 10-wk storage. Coatings also reduced ( P < 0.05) the weight loss of eggs, 4.1% to 4.8% on coated eggs compared with 7.5% in uncoated ones at the end of 10-wk storage. The pH of CL-coated eggs remained stable throughout the storage period, while the control eggs increased from 7.6 to 8.6. Color changes in CL- and WPI-coated eggshells were less ( P < 0.05) than those of BS-coated and the control. The CL coating effectively suppressed the numbers of TPC, coliforms, yeasts, and molds on peeled eggs during the 6-wk storage ( P < 0.05). The results suggest that CL coating on hard-boiled eggs can control the growth of S. Enteritidis and reduce undesirable changes in the interior quality of eggs.     

壳聚糖抗环血酸盐的制备及其抗氧化性的研究

制备了壳聚糖抗坏血酸复合盐,并研究了抗氧化性。以壳聚糖和抗坏血酸为原料制备了复合盐．对其结构进行了表征,并测定了其溶解性、稳定性、抗氧化性等性质。对原料配比、反应温度和反应时间进行探讨,发现最优工艺条件为原料配比为1：6、温度为25℃、时间为120min,在此条件下制得的复合盐有较好水溶性,在溶液中的稳定性优于抗坏血酸,清除羟基自由基的能力优于壳聚糖,从红外光谱图上可看出抗坏血酸结合于壳聚糖的氨基上。该复合盐的制备改善了其原料的性质,有利于进一步的应用。     

改性大豆分离蛋白在黑胡椒油树脂复凝聚微胶囊制备中的应用

将大豆分离蛋白(soybean protein isolate,SPI)与木糖按不同质量比混合,于90℃下反应6 h,得到美拉德反应改性的SPI,再以改性SPI和壳聚糖为复合壁材,通过复凝聚法制备黑胡椒油树脂微胶囊,研究改性SPI对黑胡椒树脂微胶囊包埋效果、热稳定性等性质的影响。结果表明,当SPI/木糖质量比为2∶1时,黑胡椒油树脂微胶囊的包埋效率、产率及80℃下加热8 h后的保留率最高,分别为67.8%、72.07%和75.06%。热重分析表明,与天然SPI相比,改性SPI进一步提高了黑胡椒油树脂微胶囊的热稳定性,扫描电镜分析则表明改性SPI使微胶囊的微观结构更加致密;气相色谱-质谱分析表明利用改性SPI-壳聚糖制备的黑胡椒油树脂微胶囊对烯类挥发性成分的保持能力增加。本研究为拓展SPI的应用领域、提高黑胡椒油树脂微胶囊的稳定性提供参考。     

Gallic Acid Grafted Chitosan Has Enhanced Oxidative Stability in Bulk Oils

Gallic acid (GA) was grafted in chitosan and the effects of GA grafted chitosan (GA‐g‐CS) on the oxidative stability in bulk oil was tested at 60 and 140 °C. To text oxidative stability in oils, headspace oxygen content, conjugated dienoic acid (CDA) value, p‐anisidine value (p‐AV), and acid value were determined. Chitosan itself did not show antioxidative or prooxidative effects in oils at 60 °C. However, GA‐g‐CS and GA acted as antioxidants at 60 °C. At 140 °C heating with moisture supplied condition, different results were observed. GA‐g‐CS acted as antioxidants based on the results of CDA and p‐AV. However, chitosan showed the highest oxidative stability based on results of acid value and brown color formation at 140 °C. This could be due to reduction of moisture content by chitosan. GA was continuously released from GA‐g‐CS in bulk oil. This might have provided extra antioxidant activities to oils.