抗坏血酸与壳聚糖处理对鲜切杨桃贮藏效果的影响

利用抗坏血酸和壳聚糖复合处理鲜切杨桃,研究其在贮藏期间的生理生化变化。研究结果表明:在贮藏温度为12℃条件下,6g/L抗坏血酸+15.0g/L壳聚糖复合处理鲜切杨桃可降低腐烂率、失重率与相对电导率,减少可溶性固形物含量损失,抑制POD、PPO活性,对鲜切杨桃起到较好的保鲜作用。     

纳米壳聚糖涂膜对鲜切茭白品质的影响

研究了纳米壳聚糖涂膜对鲜切茭白品质的影响。鲜切茭白分别在去离子水（对照）、10 g/L壳聚糖或10 g/L壳聚糖+1.5 g/L纳米壳聚糖溶液中浸泡3 min,自然晾干包装后于1±0.5 ℃下贮藏12 d。贮藏过程中每3 d测定鲜切茭白的白色指数(WI)、硬度、失重率及木质素、还原糖、抗坏血酸含量,PAL、SOD、CAT和POD活力。结果显示,纳米壳聚糖涂膜显著抑制了鲜切茭白WI值的下降和木质素含量的增加,维持了相对高的硬度及还原糖和抗坏血酸含量;贮藏12 d后失重率为1.12%;PAL和POD活性显著低于对照（P<0.05）,SOD和CAT活性显著高于对照（P<0.05）。以上结果表明,纳米壳聚糖涂膜能有效延缓鲜切茭白褐变和木质化,提高抗氧化酶类活性,提示纳米壳聚糖涂膜具有商业上控制鲜切茭白品质劣变的潜在价值。     

1-甲基环丙烯和壳聚糖对鲜切西兰花活性氧代谢及保鲜效果的影响

研究1-甲基环丙烯(1-MCP)、壳聚糖对鲜切西兰花贮藏期间活性氧代谢及保鲜效果的影响。实验设置1-MCP(2μL/L)、壳聚糖(2%)及1-MCP联合壳聚糖3个处理,以未加处理的鲜切西兰花为对照,对鲜切西兰花10℃贮藏期间的相关指标进行测定。结果表明:1-MCP处理能显著降低呼吸作用,维持较高的超氧化物歧化酶(SOD)、过氧化物酶(POD)活性,减少了O-2.和H2O2及MDA在体内的积累,延缓VC和叶绿素含量的下降,表现出很好的贮藏效果;壳聚糖处理与1-MCP处理效果相反,缩短了鲜切西兰花的贮藏时期;与对照相比,1-MCP联合壳聚糖虽有一定保鲜效果,但两者差异不明显。     

鲜切奉化芋艿褐变控制的研究

鲜切奉化芋艿容易发生褐变而丢失原有营养成分.因此对鲜切奉化芋艿采用抗坏血酸、柠檬酸、壳聚糖、氯化钙褐变抑制剂护色处理,并贮藏于4 ℃下.贮藏期间定期测定鲜切芋艿褐变度(BD)、多酚氧化酶活性(PPO).试验结果表明,鲜切芋艿在冷藏期间BD值随时间延长有增加趋势.抑制剂处理与空白组相比较,能有效抑制褐变和降低PPO活力.且4种保鲜剂单一因素抑制褐变情况和降低PPO活力效果一致,效果顺序为壳聚糖>抗坏血酸>柠檬酸>氯化钙.且单一抑制剂处理最佳浓度为:壳聚糖为0.5%、抗坏血酸为2.0%、柠檬酸为2.5%、氯化钙为0.2%.     

复合保鲜剂结合MAP对鲜切茄子贮藏品质的影响

为延长鲜切茄子的保鲜时间,研究单一气调包装(2%CO2+5%O2+93%N2)和保鲜液(1.5%壳聚糖+1%抗坏血酸+1%氯化钙+2%柠檬酸)结合气调包装对鲜切茄子品质的影响。以感官评分、褐变度、硬度、多酚氧化酶(PPO)活性和细菌总数为指标,分析鲜切茄子于(10±1)℃下贮藏8d内的品质变化。结果表明:贮藏8d后,对照组样品的L*值、硬度、PPO酶活性和细菌总数分别为75.66、7.41kg/cm2、68.77U/(min·g)和5.52lg CFU/g,而经保鲜液结合气调包装的鲜切茄子各指标分别为82.51、10.05kg/cm2、23.70U/(min·g)和2.87lg CFU/g。气调包装能够抑制鲜切茄子的褐变、萎蔫等感官品质的下降,并抑制PPO活性的增加和细菌的生长繁殖,尤其在结合保鲜液处理后效果更加明显,贮藏8d仍保持较好的品质。     

UV-C照射与壳聚糖涂膜对鲜切淮山的保鲜效果

对不同贮藏时间的鲜切淮山,采用3.0 kJ/m2剂量的短波紫外线（short-wave ultraviolet,UV-C）照射和质量浓度10 g/L壳聚糖涂膜处理,研究两种处理方法及二者协同作用对鲜切淮山生理指标的影响,探讨其保鲜效果及保鲜机理。结果表明,与对照组相比,UV-C处理鲜切淮山能够促进酚类物质和类黄酮类物质积累,增强抗氧化能力,抑制氧化损伤。壳聚糖涂膜鲜切淮山,主要通过抑制呼吸作用、降低细胞膜透性、降低细胞膜脂质过氧化而延长保鲜时间。当鲜切淮山贮藏达到12 d时,与对照组相比较,UV-C照射处理、壳聚糖涂膜、二者共同处理使呼吸强度分别降低15.7%、21.3%和23.6%,使菌落总数分别降低24.6%、18.5%和30.8%,使总酚含量分别增加13.3%、16.7%和22.2%,使1,1-二苯基-2-三硝基苯肼自由基清除率分别提高17.5%、9.6%和20.2%。由此可知,3.0 kJ/m2剂量的UV-C照射与质量浓度10 g/L壳聚糖涂膜对鲜切淮山均具有较好的保鲜效果,二者协同处理的保鲜效果更好,本研究可为鲜切果蔬的保鲜与贮藏提供借鉴。     

壳聚糖涂膜对鲜切苹果品质的影响

以山东红富士苹果为原材料,研究了不同浓度复合的壳聚糖、抗坏血酸及柠檬酸对鲜切苹果的外观和内部品质的影响。采用L9(34)正交实验设计,测定了贮藏过程中各组鲜切苹果的腐烂率、色泽、pH、可滴定酸、还原性糖等指标的变化情况。根据模糊权重法对贮藏4d的鲜切苹果外观和内部品质进行了综合评定。结果表明:选用2.0%柠檬酸、1.0%壳聚糖配制涂膜液和0.5%抗坏血酸溶液作为护色液,对鲜切苹果具有良好的保鲜效果。     

3种天然保鲜剂对凤尾菇的保鲜效果

目的:研究肉桂精油、壳聚糖和抗坏血酸3种天然保鲜剂对凤尾菇储藏过程中的保鲜效果。方法:以新鲜凤尾菇为研究对象,分别采用不同浓度肉桂精油、壳聚糖和抗坏血酸对凤尾菇进行处理,结合感官评价找出3种保鲜液的最佳浓度,并研究不同浓度保鲜剂的凤尾菇在5 ℃贮藏过程中感官评价、呼吸强度、褐变度和腐烂指数的变化规律。接着通过正交试验,以3种不同浓度的保鲜剂为考察因素,感官评价与失重率为指标,选出保鲜效果最佳的复合保鲜剂配方。结果:单一涂膜处理时,肉桂精油1.5 g/L、壳聚糖15 g/L和抗坏血酸1.0 g/L具有最好的保鲜效果。最佳的复合保鲜剂配方为,肉桂精油浓度为1.0 g/L、壳聚糖浓度为15 g/L和抗坏血酸浓度为1.0 g/L,该复合保鲜液处理凤尾菇贮藏9 d,感官评分为(78±3)分,失重率为6.98%±0.43%。结论:此复合保鲜液对凤尾菇的保鲜能起到更明显的效果,贮藏期间凤尾菇的品质和色泽均较好。     

壳聚糖及其复配对大久保桃常温贮藏特性的影响

在常温贮藏条件下利用抗坏血酸、柠檬酸、迷迭香提取物与壳聚糖复配不同保鲜剂对大久保桃失重率、腐烂率、L*值、维生素C含量、可滴定酸含量、还原糖含量、可溶性固形物含量、果肉硬度等贮藏特性指标的影响,比较不同保鲜剂复配的贮藏保鲜效果。试验结果表明,4 g/L抗坏血酸+15 g/L壳聚糖溶液浸渍涂膜、4 g/L迷迭香+15 g/L壳聚糖溶液浸渍涂膜这两组处理的保鲜效果最为明显,协同增效保鲜作用突出。     

不同抗褐变剂处理对鲜切慈姑褐变的影响

以慈姑为研究材料,研究1%抗坏血酸和0.2 g/L阿魏酸2个抗褐变剂处理对鲜切慈姑冷藏(4±1℃)过程中褐变的影响。通过测定贮藏过程中鲜切慈姑褐变度、可溶性固形物含量(TSS)、总酚、类黄酮含量、多酚氧化酶(PPO)、过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)活性等各项指标的变化,确定抗褐变剂对鲜切慈姑褐变的影响。结果发现, 2种抗褐变剂均能有效抑制鲜切慈姑的褐变,较好维持鲜切慈姑TSS含量,降低鲜切慈姑贮藏过程中总酚、类黄酮含量的上升,有效抑制褐变关键酶PPO、POD和PAL活性,不同抗褐变剂抑制效果不同,但是从褐变度和营养品质上看0.2 g/L阿魏酸处理效果较好。     

抗坏血酸、半胱氨酸与氯化钙复合处理对鲜切芋艿褐变的影响

研究抗坏血酸、半胱氨酸与氯化钙复合处理对于鲜切芋艿贮藏期间酶促褐变的控制效果及其机理。结果表明：切分后的芋艿片褐变度迅速上升,亮度（L*）值下降,苯丙氨酸解氨酶、脂氧合酶、多酚氧化酶和过氧化物酶活性升高,总酚积累。与对照相比,2.5%抗坏血酸＋0.05%半胱氨酸＋0.4%氯化钙浸泡处理能够有效降低鲜切芋艿贮藏期间的褐变度,保持较高的L*值和总酚含量,并抑制了苯丙氨酸解氨酶、多酚氧化酶、过氧化物酶和脂氧合酶活性和相对电导率的升高,达到提高鲜切芋艿贮藏品质和延长贮藏周期的目的。     

异抗坏血酸与氯化钙联合处理对鲜切芒果的保鲜效果

为研究异抗坏血酸与氯化钙联合处理对鲜切芒果保鲜效果的影响,鲜切芒果在1 g/100 mL异抗坏血酸和0.5 g/100 mL氯化钙的混合溶液中浸渍处理5 min后,4℃相对湿度80%条件下贮藏15 d,每天取样测定呼吸速率,每3 d测定细胞膜相对渗透率、硬度、可滴定酸、类胡萝卜素、抗坏血酸(AsA)、总酚、褐变指数、超氧阴离子(O₂-·)产生速率、抗氧化酶及多酚氧化酶(PPO)活性等指标。结果表明:与对照相比,异抗坏血酸+氯化钙联合处理使鲜切芒果的呼吸峰值降低了41.20%,并延缓相对渗透率升高和硬度下降;保持较高的类胡萝卜素、AsA含量,维持总酚含量相对稳定,在贮藏前期保持了较高的可滴定酸含量,减少褐变发生;降低了O₂-·产生速率,明显抑制PPO的活性,提高超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性,并且在0~9 d时延缓过氧化物酶(POD)的下降,但在贮藏后期降低了POD的活性。以上结果表明异抗坏血酸+氯化钙联合处理可以保持鲜切芒果较好的贮藏品质,延缓膜透性增加并提高活性氧(ROS)的清除能力,从而延缓衰老,抑制褐变。     

Effect of Tapioca Starch/Decolorized Hsian-tsao Leaf Gum-Based Active Coatings on the Qualities of Fresh-Cut Apples

The effect of tapioca starch/decolorized hsian-tsao leaf gum (dHG)-based edible coatings with various food additives (including ascorbic acid, calcium chloride, and cinnamon oil) on the qualities and shelf life of fresh-cut “Fuji” apple pieces was investigated during the refrigerated storage. The initial respiration rate, headspace gas composition, color, texture, microbial quality, peroxidase activity, and sensory qualities were analyzed. The results were also compared to those for samples submerged in distilled water and the samples treated with 120-ppm chlorine solution widely used in the industry. It was found that ascorbic acid and cinnamon oil delayed the browning of fresh-cut apples effectively when being applied in the starch/dHG-based edible coating solutions. In combination with calcium chloride, starch/dHG coated fresh-cut apples retained satisfactory firmness. Incorporation of cinnamon oil in starch/dHG coatings significantly reduced the growth of microorganisms, respiration rate, CO₂, and ethylene production of fresh-cut apples, but these apple pieces received lower scores in overall preference during sensory evaluation. Among the starch/dHG-based active coatings studied, starch/dHG coatings with ascorbic acid and calcium chloride are suggested for fresh-cut apples, as they could enhance qualities in terms of color and firmness, and prolong the shelf life up to 5–7 days by providing reasonable microbial quality.     

Effect of an Edible Nanomultilayer Coating by Electrostatic Self-Assembly on the Shelf Life of Fresh-Cut Mangoes

This work aims at evaluating the effect of an alginate-chitosan nanomultilayer coating, obtained by electrostatic layer-by-layer self-assembling, in the quality and shelf life of fresh-cut mangoes. Coated and uncoated fresh-cut mangoes were stored under refrigeration (8 °C) for 14 days. The changes in mass loss, titratable acidity, pH, ascorbic acid content, total soluble solids, malondialdehyde content, browning rate, and microbial count were evaluated during storage. At the end of the storage period, lower values of mass loss, pH, malondialdehyde content, browning rate, soluble solids, microorganisms’ proliferation, and higher titratable acidity were observed in the coated mangoes. The nanomultilayer coating did not improve the retention of vitamin C during storage of fresh-cut mangoes. Results suggest that chitosan-alginate nanomultilayer edible coating extends the shelf life of fresh-cut mangoes up to 8 days.     

短波紫外线处理对鲜切莲藕酶促褐变的影响

以'粉红藕'为试材,研究了短波紫外线处理对鲜切莲藕4℃冷藏过程中褐变效果的影响。主要分析了不同照射剂量(1.0、3.0和5.0 kJ/m2)下鲜切莲藕色泽、失水率、硬度、没食子酸含量、儿茶酚含量、多酚氧化酶(PPO)和超氧化物歧化酶(SOD)活性等对生理生化指标的影响。结果表明,5.0 kJ/m2剂量UV-C处理的鲜切莲藕褐变指数在贮藏第12 d时低于30,显著低于对照和其他处理组(P<0.05),5.0 kJ/m2剂量UV-C处理可通过抑制褐变底物儿茶酚、没食子酸与PPO反应来延缓鲜切莲藕的酶促褐变,并通过延缓硬度的下降,提高鲜切莲藕的贮藏品质。综合保鲜效果得出,12 d的贮藏期内,5.0 kJ/m2剂量UV-C处理抑制鲜切莲藕的褐变效果最佳。     

Cassava Starch Coating and Citric Acid to Preserve Quality Parameters of Fresh-Cut “Tommy Atkins” Mango

Abstract: Combination of citric acid dipping (5 g/L) and cassava starch coating (10 g/L), with and without glycerol (10 g/L), was studied to verify the effectiveness of these treatments to inhibit enzymatic browning, to reduce respiration rate, and to preserve quality parameters of “Tommy Atkins” fresh-cut mangoes during storage at 5 °C. Color characteristics (L* and C*), mechanical properties (stress at failure), weight loss, β-carotene content, sensory acceptance, and microbial growth of fruits were evaluated during 15 d. The respiration rate of fruit subjected to the treatments was also analyzed. Nontreated fresh-cut mango was used as a control sample. Cassava starch edible coatings and citric acid dipping promoted a decrease in respiration rate of mango slices, with values up to 41% lower than the control fruit. This treatment also promoted better preservation of texture and color characteristics of mangoes and delayed carotenoid formation and browning reactions during storage. Moreover, the treated fruit showed great sensory acceptance by consumers throughout the whole storage period. However, the use of glycerol in the coating formulation was not efficient in the maintenance of quality parameters of fresh-cut mangoes, promoting a higher weight loss of samples, impairing fruit texture characteristics, increasing carotenogenesis, and favoring microbial growth during storage. Practical Application: Consumer demand for tropical fresh-cut products is increasing rapidly in the world market. Fresh-cut mangoes are appreciated world-wide for its exotic flavor. However, its shelf life is limited by changes in color, texture, appearance, off-flavors and microbial growth. The edible coatings act as gas and water vapor barrier, extending the storage time of fresh-cut fruit and vegetables. Thus, cassava starch is an alternative to preserve minimally processed mangoes and the quality parameters of fresh fruit. The information of this work is useful for the fresh-cut produce industry to increase shelf life of fresh-cut mangoes, which can be considered an alternative to fast food and other ready-to-eat products, attending the demand for healthy and convenient foodstuffs.     

壳聚糖涂膜包装对鲜切莴苣保鲜效果的研究

以壳聚糖为成膜剂,4%的柠檬酸为溶剂配制成壳聚糖成膜液,再加入硬脂酸为增塑剂,同时加入抗坏血酸等添加剂,用浸渍的方法在鲜切莴苣表面形成壳聚糖膜,然后使其在0～4℃环境下保存5天,通过测定莴苣的硬度、多酚氧化酶(PPO)活性、过氧化物酶(POD)的活性、褐变强度(BD)、叶绿素的含量等指标进行保鲜效果分析。研究表明:用2%壳聚糖涂膜对鲜切莴苣具有良好的保鲜效果。     

臭氧联合植酸处理对鲜切水果甘蓝品质的影响

为了提高鲜切水果甘蓝的品质、延长其货架期,本实验采用臭氧处理（30?mg/L,10?min）、植酸浸泡处理（0.5?mmol/L,15?min）、臭氧联合植酸处理（先0.5?mmol/L植酸浸泡15?min,然后30?mg/L臭氧处理10?min）对鲜切水果甘蓝进行保鲜研究,以未经任何处理的样品为对照组。将水果甘蓝切分成2?cm×5?cm的小块,分别经上述处理后装入聚乙烯保鲜袋中,置于4?℃冷库中贮藏,分别测定第0、2、4、6、8天的生理生化指标和菌落总数。结果表明：贮藏第8天时,臭氧联合植酸处理组的可溶性糖、可溶性蛋白含量最高,分别是对照组的1.21、1.28?倍;同时保持了较高的抗坏血酸、硫代葡萄糖苷和异硫氰酸盐的含量;并提高了总酚含量、苯丙氨酸解氨酶、超氧化物歧化酶活力,抑制了过氧化物酶、过氧化氢酶的活力;菌落总数相比对照组低2.10（lg（CFU/g））。综上所述,臭氧联合植酸处理能较好地保持鲜切水果甘蓝的品质,延长其货架期。     

The Effects of Ultrasound Treatment and Nano-zinc Oxide Coating on the Physiological Activities of Fresh-Cut Kiwifruit

This study evaluated the efficacy of ultrasound treatment and nano-zinc oxide (ZnO) coating individually and in combination in preserving the quality of fresh-cut kiwifruit. The nano-ZnO coating solution was prepared by mixing the ZnO nanoparticles in premixed chitosan–acetic acid solution. The fresh-cut kiwifruit were dipped in NaClO solution (50 μL?L^?1 sodium, control), subjected to ultrasound treatment (40 KHz, 350 W, 10 min), or coated with nano-ZnO solution. The fresh-cut kiwifruit samples were also subjected to combined ultrasound treatment and nano-ZnO coating. All of these test samples were stored at 4 °C for 10 days. The effects of these treatments on the quality parameters such as the production of carbon dioxide and ethylene, mass loss, and flesh firmness were investigated. At the end of storage, the combination treatments with ultrasound treatment at 40 KHz with 1.2 g?L^?1 nano-ZnO coating showed lower production of ethylene (1.86 μL?kg^?1?h^?1) and carbon dioxide (10.01 mg?kg^?1?h^?1), water loss (0.46 %), and texture (7.87 N). Hence, it was concluded that the combination of ultrasound treatment with nano-ZnO coating is a promising approach to extend the shelf-life of fresh-cut kiwifruit.