碳量子点/壳聚糖涂膜剂在芒果保鲜中的应用

为了减弱芒果的呼吸作用和提高涂膜剂的抑菌效果,达到降低芒果的失水率和腐烂率的目的,以海带作为碳量子点的合成原料,通过水热法制备了水溶性较好的碳量子点,用于涂膜剂中。以壳聚糖为成膜材料,将碳量子点、柠檬酸、抗坏血酸、Ca Cl2与壳聚糖进行复配,制备纳米涂膜剂用于对芒果进行保鲜研究。结果表明,碳量子点对芒果表面的细菌和真菌具有很好的抑制作用,碳量子点/壳聚糖涂膜剂也表现出很好的保鲜效果,能有效延缓芒果中VC的氧化作用。制备的纳米涂膜剂,能够显著降低芒果的腐烂率和失水率,延缓糖和酸的转化,减弱芒果在储存过程中的呼吸作用。研究表明,碳量子点与壳聚糖等材料复配,能进一步提高涂膜剂的保鲜效果,对研发新的水果保鲜技术和材料具有重要意义。     

复配型壳聚糖涂膜剂对牛肉的保鲜研究

研究了壳聚糖复合剂对牛肉的涂膜保鲜,并进行了壳聚糖浓度的单因素试验。结果表明:保鲜效果较好的壳聚糖浓度为2%。壳聚糖复合涂膜剂的组成为壳聚糖浓度为2%,冰醋酸浓度为2%,甘油浓度为1%,其中冰醋酸为溶解剂,甘油为增稠剂。经此膜涂布后的牛肉在室温下保存72h后,其菌落总数、pH值、H2S这些理化指标仍在新鲜肉的标准范围内,比对照组延长了48h。     

茶多酚对冷藏鲫鱼鱼片品质的影响

以鲫鱼鱼片为材料,试验分别设置了1.5%、2.0%和2.5%三种茶多酚浓度,蒸馏水作空白对照,以细菌总数、L~*值和b~*值、TBA值、pH和硬度为指标,研究不同浓度茶多酚对冷藏鲫鱼鱼片物理指标和化学指标的影响。结果表明,与空白对照组相比,各处理组的鲫鱼鱼片的细菌总数、L~*值和b~*值、TBA值、pH和硬度均优于空白对照组,且在一定范围内,随着茶多酚浓度增加,冷藏鲫鱼鱼片的贮藏效果增加,其中浓度为2.5%的茶多酚对鲫鱼鱼片的保鲜效果最为显著。冷藏18d时,经过2.5%茶多酚处理的鲫鱼鱼片的TBA为2.14mg/100g,细菌总数为6.21lgccfu/g,pH为6.92,硬度为20.62N,L~*值为42.48,b~*值为2.48,贮藏期至少为18d,明显优于其他组处理。综合各项理化可知,茶多酚能够明显延长鲫鱼鱼片的贮藏期,提升鲫鱼鱼片的贮藏品质,达到保鲜的效果。     

壳聚糖保鲜剂涂膜对保鲜葡萄的效果研究

研究了壳聚糖保鲜剂涂膜保鲜葡萄。采用壳聚糖为成膜主剂,表面活性剂为助剂,测定了添加不同表面活性剂的壳聚糖溶液的吸光度和涂布效果。在此基础上,添加不同金属离子的壳聚糖复合保鲜液对葡萄进行了涂膜保鲜处理,并测定了葡萄在贮藏过程中失重率、褐变指数、VC含量和总酸度等生理指标的变化。结果表明：在1%的壳聚糖溶液中添加2%吐温-20、Ca2＋或Cu2＋对葡萄的保鲜效果较好,能有效降低葡萄的失重率,延缓葡萄中总酸度的变化。添加了Ca2＋和Cu2＋的壳聚糖保鲜液对葡萄有较明显的保鲜效果。     

水溶性壳聚糖的制备及其在葡萄保鲜中的应用

进行了在超声波的作用下用H2O2降解壳聚糖的研究,制备出用于水果保鲜的水溶性的壳聚糖涂膜剂,并用该涂膜剂进行了葡萄的常温保鲜效果研究.实验结果表明,超声波能显著促进壳聚糖的降解速率;1%的水溶性壳聚糖涂膜剂能有效抑制过氧化酶的活性,可减缓在贮存期间营养成分的损失.     

羧甲基壳聚糖复合涂膜的银条保鲜效果研究

银条是具有多种活性物质的药食两用特种蔬菜。为解决银条的保鲜问题,以羧甲基壳聚糖为主要成分,添加其他助剂配制了复合涂膜剂,研究了该涂膜剂用于银条的保鲜效果。实验结果表明,该涂膜剂(含2％羧甲基壳聚糖)用于银条的保鲜,能够延长银条的贮藏期。     

壳聚糖涂膜保鲜竹笋研究

选用壳聚糖作为涂膜剂处理带壳小竹笋，在4℃低温，相对湿度94%条件下贮藏保鲜25d。贮藏期间对竹笋的失重率、纤维素和VC含量以及氨基酸总量进行了测定。试验结果表明：1.5%壳聚糖混入1.0%对羟基苯甲酸乙酯制成的涂膜剂有较好的保鲜效果，抑制失重和纤维素含量增加有明显效果。用同法处理的带壳乌笋保鲜效果比雷笋好。     

壳聚糖/纳米蒙脱土复合涂膜对枇杷保鲜的研究

采用壳聚糖和纳米蒙脱土作为复合涂膜剂,研究室温条件下对枇杷的保鲜效果。结果表明,壳聚糖/纳米蒙脱土复合涂膜剂能明显延缓水分流失,抑制硬度、VC含量、总糖含量和总酸含量的下降,有效延长枇杷保质期。     

蜂胶涂膜剂在番茄保鲜中的应用

采用蜂胶涂膜剂对番茄进行保鲜处理,通过正交实验法对蜂胶涂膜剂配方进行优化.通过测定番茄样品的感官变化、失重率变化及维生素(:含量的变化,确定番茄保鲜效果.实验结果表明,最佳的蜂胶涂膜剂配方是蜂胶浓度为0.5%、明胶浓度为1%、蔗糖酯浓度为0.1%,此时番茄样品保鲜效果最好,可以有效延长番茄样品的货架期.     

壳聚糖涂膜保鲜金柑的研究

用不同浓度的壳聚糖作为涂膜剂对金柑进行涂膜处理,在室温条件下贮藏保鲜.测定了果实失重率、Vc、可溶性固形物、可滴定酸、总糖、呼吸强度和过氧化氢酶活性等指标的变化,并与未经涂膜的进行对比,以试验比较壳聚糖涂膜保鲜对延长金柑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,其中以浓度为0.8%壳聚糖保鲜效果最佳.     

含肉桂精油的壳聚糖涂层对冷藏草鱼片的保鲜作用

通过在草鱼片上添加含肉桂精油(CIN)的壳聚糖(chitosan,Ch)涂层,研究含肉桂精油的壳聚糖涂层对草鱼片(4±1)℃ 冷藏16 d期间品质的影响.涂层分别采用质量浓度20 g/L Ch和Ch+CIN[质量浓度20 g/L Ch+1.5％(体积分数)CIN]配方溶液,对未添加涂层和添加不同配方涂层鱼片样品的微生物...     

Effect of silver carp (Hypophthalmichthys molitrix) muscle hydrolysates and fish skin hydrolysates on the quality of common carp (Cyprinus carpio) during 4 °C storage

Silver carp (Hypophthalmichthys molitrix) skin and muscle were hydrolysed, respectively, and then used as part of an edible coating to preserve fish. The effects of muscle and skin hydrolysates as edible coatings for shelf life extension of common carp (Cyprinus carpio) were evaluated over 18 days at 4 °C, by comparing these two treatments, a chitosan coating with muscle hydrolysate, chitosan alone, and an untreated control. All coatings were made up with 5% glycerol. The quality of the carp was assessed by using total volatile basic nitrogen (TVB‐N), total viable counts (TVC), thiobarbituric acid (TBA) and K value. Compared with the control group, the rate of increase in TVB‐N, TVC, TBA and K value of carp coated with fish skin hydrolysates, fish muscle hydrolysates and chitosan added to fish muscle hydrolysates were lower. According to the total viable counts, the storage life of fish with fish skin hydrolysates coatings and chitosan added fish muscle hydrolysates coatings were 16 days, 2 days longer than those with the chitosan coatings and twice as long as the control group.     

鲢鱼皮改性明胶复合多肽锌对草鱼的保鲜作用

研究鲢鱼皮谷氨酰胺转胺酶（transglutaminase,TGase）改性明胶复合多肽锌对冷藏草鱼段的保鲜效果。通过测定草鱼段在4 ℃冷藏过程中感官评分、硫代巴比妥酸（thiobarbituric acid,TBA）、挥发性盐基氮（totalvolatile basic nitrogen,TVB-N）、pH值和菌落总数等指标,评估不同处理条件下草鱼品质的变化情况。结果表明,改性明胶及其复合多肽锌对草鱼均有明显的防腐保鲜作用,有效抑制了草鱼TBA值、TVB-N值、pH值的升高以及菌落总数的增长。与海藻酸钠多肽锌处理的涂膜组草鱼相比,改性明胶单独涂膜组的保鲜效果与之相当,而改性明胶复合多肽锌膜组在贮藏前6 d的保鲜效果明显比海藻酸钠复合多肽锌组更好,一级及二级鲜度贮藏期均比海藻酸钠多肽锌复合组延长了3 d。因此,与海藻胶相比,改性鱼皮明胶是一种良好的涂膜材料,可以有效提高水产品的保质期。     

改良壳聚糖涂膜技术对草鱼肉抑菌保鲜效果的研究

壳聚糖溶液涂膜是一种新兴的保鲜技术,具有较好的保鲜效果和优越性,但尚存在成膜较慢、不易操作、膜层厚度难控制等缺点,因而改善涂膜液的组成和涂膜技术是涂膜保鲜的关键。本文研究了新的涂膜方式和添加易挥发的乙醇来改进壳聚糖涂膜液的成膜和抑菌效果。通过改变不同乙醇浓度、壳聚糖浓度和涂膜方式等条件,分析其对冷藏过程中草鱼肉的微生物菌落总数和TVB-N值的影响。结果表明,涂膜溶液中含有75%的乙醇时,不仅对冷藏草鱼肉的抑菌效果好,而且还具有减菌作用,使样品初始微生物菌落总数降低超过51%;壳聚糖浓度为1.0%时,涂膜液的成膜效果及对草鱼肉的抑菌效果均较好;此外,涂膜方式对其效果影响不明显,但喷雾涂膜处理相对方便、经济。因此,以含有75%乙醇的壳聚糖酸性涂膜保鲜剂喷雾涂膜是一种成膜和抑菌效果均好的改良型鱼肉保鲜技术。     

顶空固相微萃取与GC-MS联用法分析淡水鱼肉气味成分

本文以我国主要食用养殖淡水鱼鲢、鳙、鲫和草鱼为原料,采用涂有聚二甲基硅氧烷-二乙烯苯(PDMS-DVB)涂层的固相微萃取头萃取鱼肉蒸馏后的挥发性成分,在相同的顶空固相微萃取(HS-SPME)条件和气-质联用仪(GC-MS)检测条件下,分析了鲢、鳙、鲫和草鱼肉中的挥发性成分组成,分别检出鲢、鳙、鲫和草鱼肉中有40、42、42、31种挥发性成分,均以挥发性羰基化合物和醇类为主,其相对百分含量分别为63.33%、72.69%、76.16%和55.40%.感官评定结果表明鲫和鳙的气味相近,四种鱼肉按气味的强弱排列次序为鲫、鳙、鲢、草鱼.推测挥发性羰基化合物和醇类含量越高,气味越强烈.     

复配生物涂膜保鲜液对冷藏南美白对虾的保鲜效果研究

目的探究复配生物涂膜保鲜液对冷藏南美白对虾的保鲜效果。方法以新鲜南美白对虾为原料,通过单因素实验考察壳聚糖、海藻酸钠、明胶及乳酸链球菌素(Nisin)对冷藏南美白对虾货架期的作用。在此基础上优化壳聚糖、海藻酸钠及Nisin所组成的复配涂膜保鲜液的最适配比。结果壳聚糖6 g/L、海藻酸钠8 g/L、Nisin 0.4 g/L组成的最佳配比复合保鲜液涂膜南美白对虾后冷藏保存,冷藏期限可以达到12 d,测得pH值为7.52,感官评分为3分,比对照组延长了6 d。结论南美白对虾涂膜复合保鲜液后,更能隔绝外界接触,抑制细菌繁殖,从而延缓虾肉的腐败变质,具有更好的保鲜效果,为进一步研究南美白对虾货架期与特定腐败微生物关系奠定理论基础。     

Effects of chitosan coating combined with essential oils on quality and antioxidant enzyme activities of grass carp (Ctenopharyngodon idellus) fillets stored at 4 °C

Effects of chitosan coating combined with essential oils from clove, cinnamon and lemon grass on quality and antioxidant enzyme activities of grass carp fillets stored at 4 ± 0.5 °C were evaluated. The quality parameters (including pH, total volatile basic nitrogen (TVB‐N), K value, thiobarbituric acid (TBA) value, shear force and total viable count (TVC)) and antioxidant enzyme activities were analysed periodically. The results indicated that composite chitosan coatings presented better preservation effects than chitosan coating alone. In addition, chitosan–clove essential oil coating had the best quality enhancement effects among treatments by inhibiting deterioration of physicochemical quality and microbial growth and maintaining antioxidant enzyme activities of fillets during refrigerated storage. The negative correlation was observed between the changes in TBA values and antioxidant enzyme activities in fillets. Based on these findings, chitosan–essential oil coatings effectively mitigated oxidative stress and extended shelf life of refrigerated grass carp fillets.     

Effects of chitosan coating on quality and shelf life of silver carp during frozen storage

The effects of chitosan coating on quality and shelf life of silver carp during frozen storage were investigated. Fish samples were treated with aqueous solution of 2% chitosan, and then stored at −3 °C for 30 days. The control and the treated fish samples were analyzed periodically for microbiological (total viable count), chemical (pH, TBA, TVB-N, K-value), and sensory characteristics. The results indicated that the effect of chitosan coating on fish samples was to retain their good quality characteristics and extend the shelf life during frozen storage, which was supported by the results of microbiological, chemical, and sensory evaluation analyses.     

Impact of Wall Materials on Physicochemical Properties of Microencapsulated Fish Oil by Spray Drying

The aim of the present study was to investigate the effect of wall materials composition on physicochemical characteristics of fish oil microcapsules produced by spray drying (180 °C). Four different combination of coating materials (fish gelatin, chitosan, combination of gelatin and chitosan, and a mixture of microbial transglutaminase (MTGase) with maltodextrin) were applied to two different fish oils to produce 40 % solid emulsions. Scanning electron microscopy and extraction of surface and encapsulated oils revealed that fish gelatin provided the highest preserving effect on the covering fish oil. Meantime, addition of MTGase to gelatin could also increase this ability and reveled less surface oil than chitosan treatment (2.63 and 2.80 % versus 4.66 and 5.23 %, respectively; P?<?0.05). Mixture of gelatin and maltodextrin with MTGase as wall material led to the highest encapsulation efficiency, being selected as the best microencapsulation condition; meantime, application of chitosan with maltodextrin provided the worse encapsulation efficiency (P?<?0.05). All indices of powders (encapsulation efficiency, surface morphology, and particle size) showed that powders prepared from gelatin and gelatin with MTGase increased the encapsulation efficiency and would increase the stability of microcapsule powders.     

Combined Effect of Polyphenol‐Chitosan Coating and Irradiation on the Microbial and Sensory Quality of Carp Fillets

Irradiation can extend the shelf‐life of fish, but it may cause unacceptable change on quality. Since rose polyphenols have high antioxidant and antibacterial activities, this study evaluated the combined effect of polyphenol‐chitosan coatings and irradiation (3 kGy) on the microbial and sensory qualities of carp fillets during storage at 4 °C. A dose of 3 kGy irradiation reduced the initial total viable counts (TVC) and psychrophiles, and increased the initial b^* and thiobarbituric acid reactive substance (TBARS) values. During storage, TBARS, TVC and psychrophiles of nonirradiated samples increased faster and were higher than those irradiated. Regardless of irradiation treatment, samples coated with chitosan containing rose polyphenols had lower TBARS, pH and bacteria than that in no coating or chitosan coating batches. Carp treated with combined treatment could preserve an acceptable sensory quality at the end of storage. The result indicated that polyphenol‐chitosan coating combined with irradiation can maintain fish quality by preventing bacterial growth, oxidation, and changes in color and sensory acceptability.