山苍子精油/壳聚糖涂膜保鲜对黄颡鱼贮藏品质的影响

为研究山苍子精油(Litsea cubeba oil, LCO)与壳聚糖(Chitosan, CS)协同处理对黄颡鱼贮藏品质的影响,以黄颡鱼为实验材料,采用对照组、壳聚糖涂膜、不同浓度山苍子精油/壳聚糖组复合涂膜(0.2%、0.4%、0.6%)处理。4℃下贮藏保鲜13 d,测定其肌肉p H值、挥发性盐基氮(Total volatile basic nitrogen, TVB-N)值、菌落数、硫代巴比妥酸(Thiobarbituric acid, TBA)值、质构与感官评价等指标变化。结果显示：经CS+LCO处理,可有效延缓pH值、TBA值、TVB-N值及菌落总数的上升速度。贮藏至第9天时,pH值、TBA值、TVB-N值及菌落总数分别比对照组低3.3%、37.7%、38.17%、11.74%。同时,CS+LCO处理组肌肉的硬度、弹性、咀嚼度、回复性等质构指标下降减缓,感官评分高于同期其他样品。因此可见,LCO/CS涂膜能较好保持黄颡鱼的贮藏品质,延长其货架期,其中以CS+0.6%LCO处理效果最佳。     

壳聚糖复合涂膜对冷藏虾蛄保鲜效果的影响

以虾蛄为研究对象,选用壳聚糖、维生素C、玉米淀粉为复合涂膜材料,以壳聚糖单一涂膜和空白作为对照,以感官、菌落总数(TVC)、pH值、挥发性盐基氮含量(TVB-N)、硫代巴比妥酸值(TBA)等为指标,研究复合涂膜对冷藏虾蛄品质的影响。结果表明:壳聚糖—维生素C—玉米淀粉复合涂膜有效延缓了虾蛄样品的菌落总数、pH值、TVB-N值、TBA值的上升,且效果优于空白组和壳聚糖单一涂膜组;与空白组相比,壳聚糖—维生素C—玉米淀粉复合涂膜可延长冷藏虾蛄货架期2~3 d。     

山梨酸和涂膜联合作用延长青虾货架期的效果

将经过山梨酸处理后的青虾浸渍于不同的壳聚糖涂膜溶液后冰藏保鲜,其中壳聚糖复合膜液是将山梨酸加入壳聚糖溶液中制得。在保鲜过程中测定青虾细菌总数、TVB-N值、pH等鲜度指标并进行感官评分,探索采用山梨酸和涂膜联合作用延长青虾货架期的效果。实验结果表明:仅经过山梨酸处理的青虾保鲜效果不佳,而在山梨酸处理后再进行涂膜保鲜可以抑制虾体细菌总数的增长,维持较低的TVB-N值,改善青虾的感官质量,延长青虾货架期约3d。壳聚糖空白膜液处理的青虾感官品质优于经过复合膜液处理的青虾。     

涂膜对微冻杂色蛤的保鲜作用

以pH值、细菌总数、挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBA)、Ca2+-ATPase活性等为鲜度指标,研究壳聚糖、海藻胶在-3℃条件下对杂色蛤的保鲜效果。试验结果表明:经壳聚糖、海藻胶处理的杂色蛤肉再进行微冻冷藏,其pH值、细菌总数、TVB-N值、TBA值明显低于对照品,Ca2+-ATPase活性明显高于对照品。可食性涂膜在杂色蛤微冻保鲜过程中能有效抑制细菌繁殖,减缓脂肪氧化,延缓腐败变质,从而延长杂色蛤的保鲜期。     

茶多酚结合壳聚糖对冷却肉的保鲜效果

为了延长冷却肉的货架期,文中采用不同浓度茶多酚结合壳聚糖与可食性膜溶液混合制成涂膜保鲜剂,通过测定贮存过程中冷却肉的细菌总数、挥发性盐基氮(TVB-N值)、pH值、色差值、硫代巴比妥酸值(TBA值)等指标的变化,对冷却肉保鲜效果进行研究。结果表明:0.7%茶多酚、1.0%壳聚糖涂膜保鲜冷却肉效果较好,显著优于对照组和单纯使用壳聚糖涂膜保鲜组,在0～4℃条件下能将冷却肉保鲜期延长至16 d以上。     

添加剂对壳聚糖涂膜保鲜虾的效果研究

在壳聚糖涂膜液中,加入防腐剂Nisin和抗氧化剂Vc对虾进行涂膜处理,以感官评定、细菌总数、TVB-N值、TBA值及DH值作为鲜度指标,并与无添加剂的和未经涂膜的进行对比,以实验壳聚糖涂膜保鲜对延长虾货架期的可行性及其效果,以及添加剂对涂膜的效果.实验结果表明:壳聚糖涂膜保鲜效果明显优于未经涂膜的对照组,且有添加剂的效果更明显.其各项指标均较对照组有明显差异,涂膜后的鲜虾能延长保质期2～3 d.     

壳聚糖涂膜保鲜虾的研究

用不同浓度的壳聚糖作为涂膜剂,并加入适量添加剂对虾及虾仁进行涂膜处理,在室温条件下贮藏保鲜。以感官评定、细菌总数、TVB-N值作为鲜度指标,在贮藏期间进行了鲜度指标的测定,并与未经涂膜的进行对比,以试验壳聚糖涂膜保鲜对延长虾货架期的可行性及其效果。并根据不同浓度的涂膜效果,来确定最佳的壳聚糖涂膜浓度。实验结果表明:壳聚糖涂膜保鲜效果明显优于未经涂膜的对照组,其各项指标均较对照组有明显差异,能延长保质期2～3d。且以浓度为1.5%壳聚糖保鲜效果最佳。     

复合涂膜处理对中国对虾保鲜的影响

利用壳聚糖、ε-聚赖氨酸和卡拉胶进行复合涂膜,以感官评定、菌落总数、pH、TVB-N、TBA、质构特性、SDS-PAGE凝胶电泳为指标,探究(4±1) ℃条件下不同涂膜处理对中国对虾保鲜效果的影响。研究表明:涂膜组的保鲜效果明显优于空白组,且复合涂膜效果优于单独涂膜。涂膜处理能够抑制贮藏期间细菌的生长,延缓蛋白质和脂肪的氧化变质。与空白组相比,复合涂膜可以将中国对虾的货架期延长4 d。     

壳聚糖和茶多酚对罗非鱼冷藏保鲜效果比较

本文以罗非鱼为原料,比较壳聚糖和茶多酚对罗非鱼冷藏保鲜的效果.以感官评分、细菌总数、pH值、挥发性盐基氮(TVB-N值)、硫代巴比妥酸(TBA值)、鲜度指标(K值)等作为质量指标,测定罗非鱼在4℃冷藏过程中品质变化.试验结果表明,经茶多酚和壳聚糖处理的罗非鱼再进行冷藏,罗非鱼的感官评分值下降缓慢,细菌总教、TVB-N值...     

白藜芦醇和壳聚糖复合生物保鲜剂对冷藏鱿鱼品质的影响

为了降低鱿鱼中甲醛含量和改善鱿鱼的贮藏品质,研究了白藜芦醇和壳聚糖对鱿鱼品质和货架期的影响。实验分为对照组、白藜芦醇组(0.2%)、壳聚糖组(1.0%)、白藜芦醇(0.2%+壳聚糖1.0%)组。鱿鱼在(0±0.5) ℃贮藏20 d。以挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBA)、硬度、弹性、甲醛含量的变化、菌落总数(TVC)和感官评分作为评价指标,研究其对鱿鱼的保鲜效果。结果表明:相对对照组,白藜芦醇+壳聚糖显著(p<0.05)降低菌落总数、TVB-N、TBA值和甲醛含量,使硬度和弹性下降程度变缓,显著提高感官评分。白藜芦醇+壳聚糖能够改善鱿鱼的品质,抑制微生物的增殖,并减缓脂肪氧化,延长鱿鱼的货架期,可以用于鱿鱼的保鲜。     

The effect of chitosan coating incorporated with ethanolic extract of propolis on the quality of refrigerated chicken fillet

Chitosan is considered as a functional packaging component for maintaining the quality and increasing the shelf life of perishable foods include meat, poultry, fish, dairy products, and all cooked leftovers. The present study was conducted to evaluate edible coating of chitosan (2%) containing ethanolic extract of propolis (1% and 2%) on microbiological (mesophilic aerobic, psychrotrophic, lactic acid bacteria, coliforms, and Staphylococcus aureus counts), chemical (TBARS, TVN and Peroxide values) and sensory (odor, color, texture, taste, and overall acceptance) properties of chicken fillet. Microbial analysis showed that coating had a significant reducing effect on growth of bacteria during 12 days at 4 °C. Besides, the increase of TBARS, Total volatile nitrogen, and peroxide value of samples coated by chitosan and ethanolic extract of propolis was less than control group. According to our results, chitosan and propolis can be used to enhance the shelf life of fillet and maintain its quality.

Practical applications

Propolis is used for infections caused by bacteria, viruses, fungus, and by single‐celled organisms called protozoans. Propolis is also used as an antioxidant and anti‐inflammatory agent. Ethanol extract of propolis improve the properties of chitosan edible coating in chicken fillet preservation. The chitosan coating incorporated with ethanolic extract of propolis can improve the microbial, chemical, and sensory quality of food and enhance the shelf life of them by synergistic effects.     

茶多酚-壳聚糖复合液对虹鳟鱼肉贮藏品质和菌群结构的影响

针对虹鳟鱼在贮藏过程中易受到微生物的污染而发生腐败变质的问题,将3 g/L茶多酚和10 g/L壳聚糖混合制成复配保鲜剂,浸泡涂膜覆盖于虹鳟鱼表面。以感官评价、挥发性盐基氮含量、菌落总数及菌群结构等为指标,研究保鲜剂对4℃贮藏虹鳟鱼肉贮藏品质变化的影响。结果表明:茶多酚和壳聚糖单独使用或复合使用均能延缓腐败的发生;复配保鲜剂能将4℃贮藏虹鳟鱼的货架期从8 d延长至13 d,效果优于单独使用;未经处理的新鲜虹鳟鱼片菌群由16个菌属组成,腐败末期则以假单胞菌属为优势菌属,而复合保鲜剂涂膜会明显抑制假单胞菌属的生长,进而减缓鱼肉品质劣变。综上,茶多酚和壳聚糖的复配保鲜剂有助于通过抑制优势腐败菌的生长延缓4℃贮藏条件下虹鳟鱼的腐败变质。     

壳聚糖-咖啡酸衍生物涂膜对多宝鱼保鲜效果的研究

以多宝鱼为试材,采用质量分数为0.20%的咖啡酸、2%的壳聚糖、0.20%的咖啡酸、1.8%的壳聚糖,2%壳聚糖-咖啡酸衍生物以及无菌水5种不同溶液浸泡处理,通过测定4℃冷藏5 d期间挥发性盐基氮、菌落总数、pH值、持水力以及感官评价等指标的变化,探讨壳聚糖-咖啡酸衍生物复合涂膜对多宝鱼的保鲜效果。结果表明:4℃下贮藏5 d后,相较于以无菌水处理的样品,4种不同处理均能够在一定程度上延缓多宝鱼的挥发性盐基氮、菌落总数、pH值的升高,降低样品的持水力。4种不同处理相比较,2%壳聚糖-咖啡酸衍生物涂膜对多宝鱼保鲜效果最好。     

高温条件下涂膜保存对禽蛋品质的影响

选用具有抑菌作用的保鲜剂壳聚糖和苯甲酸钠对产后12h内的褐壳鸡蛋进行涂膜处理,研究其在夏季的保鲜效果.将鸡蛋的感官评价、品质变化及部分微生物变化作为衡量鸡蛋新鲜度变化的各种指标.结果表明,保存32d,对照组蛋壳表面的菌落总数超过鲜蛋卫生标准和绿色鸡蛋标准,但对照组和壳聚糖组的蛋内容物中菌落总数、大肠杆菌、沙门氏菌均未检...     

鸡蛋不同保存方法品质变化规律的研究

选用具有抑菌作用的保鲜剂壳聚糖和苯甲酸钠对产后12h内的褐壳鸡蛋进行涂膜处理,研究其在夏季的保鲜效果。将鸡蛋的感官评价、品质变化及部分微生物变化作为衡量鸡蛋新鲜度变化的各种指标,结果表明,保存32d,对照组蛋壳表面的菌落总数超过鲜蛋卫生标准和绿色鸡蛋标准,但对照组和壳聚糖组的蛋内容物中菌落总数、大肠杆菌、沙门氏菌均未检出;保存28d时,对照组的哈氏单位仪器全部检测不出来,壳聚糖处理组在40d全部检测不出来,降为次鲜蛋。此外,蛋的失重率、蛋黄指数和气室高度及其它一些检测指标均好于对照组。     

壳聚糖和茶多酚对鸡肉的保鲜效果及复合保鲜条件的优选

通过测定冷藏过程中鸡肉的细菌总数、挥发性盐基氮(TVB-N)含量、pH值及感官品质,分别研究了壳聚糖及茶多酚对鸡肉冷鲜效果的影响,并结合臭氧浸洗及添加L-抗坏血酸(VC)实现增效,优化出鸡肉复合保鲜处理最优条件:鸡肉经臭氧浓度8 mg/L浸泡清洗20 min,而后浸涂于含有1.5%壳聚糖、0.3%茶多酚及0.5%Vc的复合保鲜液中,可使鸡肉的冷鲜期延长至28 d,保鲜效果明显。     

壳聚糖降解液对鲜切莴笋的防腐保鲜效果

用常温水解壳聚糖得到的粘均相对分子质量Mv在1500～2000的降解液、结合热处理对鲜切莴笋进行保鲜试验。结果表明,采用质量分数50%的壳聚糖降解液、45℃浸泡2min的处理方法,鲜切莴笋的微生物生长以及褐变被明显抑制,在贮藏期9d内,细菌总数在106cfu/g左右,PPO活性峰值比对照降低46%,Vc含量高于对照56%,感官品质保持良好。     

Influence of chitosan/clay functional bionanocomposite activated with rosemary essential oil on the shelf life of fresh silver carp

A combination of chitosan biopolymer, nanoclay and rosemary essential oil was prepared as a functional bionanocomposite (FBN). Its ability to improve the shelf life of refrigerated (4 ± 1 °C) silver carp fillets was studied. The fresh fillets were left untreated as a control or coated with chitosan, chitosan/clay bionanocomposite and chitosan/clay/rosemary essential oil (Ch/clay/REO) FBN. Then, they were evaluated for chemical, microbial and sensory properties over 16‐day storage. The samples coated with the FBN had the lowest pH and total volatile basic nitrogen. Ch/clay/REO coating efficiently retarded lipid oxidation by decreasing peroxide, free fatty acid and thiobarbituric acid production in the samples. The coating also reduced total viable and psychrotrophic count of the fillets more than 1.5 log by the end of storage.     

The effect of edible eggshell coatings on egg quality and consumer perception

Effects of the various coatings (whey protein isolate, chitosan and shellac) on fresh eggs quality were evaluated based on the interior quality and sensory evaluation during 4 weeks of storage. During storage, all egg weights and albumen heights decreased and albumen pH increased. The lowest weight loss (0.75%) was observed in shellac‐coated eggs. Eggs coated with chitosan and whey protein also had significantly lower weight loss than uncoated (UC) eggs (p < 0.05). The albumen pH of the UC eggs was significantly higher than that of coated eggs and increased during storage time. The Haugh unit and yolk‐index values of all coated eggs were significantly higher than those of UC. Among the coated eggs, the shellac eggs had the highest value of Haugh unit and yolk index. Chitosan and shellac effectively maintained grade ‘A’ eggs for at least 2 weeks more than control and 1 week more than whey protein isolate. On the basis of sensory evaluation, shellac has highest glossiness, but lowest general acceptability. Eggs coated with whey protein had significantly higher general acceptability. Yolk lightness (L*)(a*) and (b*) of coated eggs were not different from UC after 4 weeks. The values of color differences were similar to controls. The study demonstrated that various coatings improved the shelf life of eggs. Copyright © 2005 Society of Chemical Industry