茶树精油电辅助加热熏蒸处理对草莓品质和相关酶类的影响

为了减少精油用量、节约成本,对茶树精油采用电辅助加热的熏蒸处理方法,分析该方法对草莓果实贮藏期间品质和代谢相关酶类的影响。结果表明,0.001%的茶树精油熏蒸处理可以减缓可溶性固形物(total soluble solid,TSS)含量和硬度的下降,维持果实表面的亮度和红度,减缓果实贮藏期间过氧化氢(H_2O_2)含量的上升,提高过氧化氢酶(catalase,CAT)和多酚氧化酶(polyphenol oxidase,PPO)活性,降低抗坏血酸过氧化物酶(ascorbate peroxidase,APX)和苯丙氨酸解氨酶(phenylalanine ammonia lyase,PAL)的活性,对超氧化物歧化酶(superoxide dismutase,SOD)和β-1,3-葡聚糖酶几乎无影响。可见,电辅助加热茶树精油熏蒸处理可以在节约精油用量的同时,较好地保持草莓的品质,延缓果实衰老。     

葫芦巴精油对采后樱桃番茄果实贮藏品质的影响

以樱桃番茄为试材,用不同浓度的葫芦巴精油在40 ℃条件下熏蒸30 min,将处理后的樱桃番茄恒温贮藏于20 ℃下,分别测定其在贮藏期间过氧化物酶(POD)活性、可滴定酸、可溶性还原糖含量等品质指标的变化,探究在20 ℃储藏条件下葫芦巴精油处理对樱桃番茄果实采后品质的影响。结果表明,葫芦巴精油能够提高樱桃番茄的贮藏效果,其中7.5 μL葫芦巴精油对保持果实的可溶性固形物含量、可滴定酸和可溶性还原糖含量相对较好,10 μL葫芦巴精油能较好保持樱桃番茄的POD活性,延缓Vc含量的下降,减缓果实硬度的变化,使果实的腐烂指数下降。综上可知,7.5～10 μL葫芦巴精油能较好地保持樱桃番茄在20 ℃下的贮藏品质,能够延长樱桃番茄的贮藏时间。     

柠檬醛对草莓贮藏期间品质和抗氧化能力的影响

目的 探讨不同植物精油对草莓贮藏期间品质和抗氧化能力的影响，为草莓保鲜提供新的方法。方法 以“红颜”草莓为试材，分别用不同质量浓度（40、80、160和320 μg/mL）的百里香精油、丁香花精油、肉桂精油、枯茗醛和柠檬醛进行处理，测定其在20℃贮藏期间的失重率、腐烂指数、理化性质、抗氧化物质含量和抗氧化酶活性等指标。结果 柠檬醛在40 μg/mL质量浓度时具有最佳保鲜效果，能够有效地降低草莓果实的失重率和腐烂指数，延缓可溶性固形物、可滴定酸和抗坏血酸含量的下降，维持较高的总酚和总黄酮含量，并提高果实对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl, DPPH）自由基和羟基自由基的清除能力。此外，该处理还能显著提高过氧化氢酶、超氧化物歧化酶、抗坏血酸过氧化物酶等抗氧化酶的活性，且有效抑制丙二醛含量的升高。结论 柠檬醛在草莓贮藏中具有良好的保鲜效果，能够保持其品质和营养价值，这为柠檬醛在水果贮藏保鲜中的应用提供了依据。     

不同浓度1-PentCP处理对芒果常温贮藏生理品质的影响

研究了不同浓度（1、5、50μL/L）的环丙烯类乙烯效应抑制剂1-PentCP（1-pentylcyclopropene,1-戊基环丙烯）常温（20±2）℃熏蒸处理20h对芒果果实（Mangifera indica L.）贮藏生理和品质的影响。结果表明,1-PentCP熏蒸处理能明显抑制果实的呼吸强度并延迟呼吸高峰的出现时间,延缓果实硬度、可滴定酸含量的下降和MDA（丙二醛）、SSC（可溶性固形物）含量的上升,并降低POD（过氧化物酶）、PPO（多酚氧化酶）酶的活性。说明1-PentCP处理能有效延缓芒果的后熟和衰老,抑制芒果贮藏期间品质的下降,其中以50μL/L1-PentCP的效果较佳。      

壳聚糖-姜精油涂膜对草莓贮藏品质的影响

采用浓度为1%的壳聚糖与不同浓度(0.05%、0.10%、0.20%)的姜精油配制成保鲜液,对草莓进行涂膜处理,研究壳聚糖-姜精油对草莓贮藏品质的影响。结果表明,不同浓度的姜精油与壳聚糖保鲜液对草莓的保鲜效果表现不一,较低浓度的壳聚糖-姜精油保鲜液能够降低草莓的腐烂率、失重率、细胞膜的透性和丙二醛含量,减少可滴定酸、VC和可溶性糖含量的损失,有效地保持草莓的感观品质,能够更好地延缓草莓贮藏品质的下降。其中,壳聚糖-0.10%姜精油保鲜液处理草莓的贮藏品质最佳,而壳聚糖-0.20%姜精油保鲜液处理的草莓贮藏品质较差。     

热空气处理对草莓果实品质和抗氧化活性的影响

研究热空气处理（45 ℃,3.5 h）对草莓在20 ℃、4 d贮藏期间果实品质、抗氧化活性及相关基因表达的影响。结果表明,热空气处理可以显著抑制果实腐烂的发生,延缓果实硬度、总黄酮、总酚和VC含量的下降,抑制花青素的积累,保持较高的DPPH自由基清除能力和还原力。另外,热处理可显著促进果实中黄酮醇合酶、查耳酮合酶和苯丙氨酸解氨酶基因的表达,而抑制β-木糖苷酶和花青素合酶基因的表达。这些结果表明,热空气处理可以通过调控相关基因的表达,较好地保持果实的品质和抗氧化活性。     

柠檬烯处理对鲜切哈密瓜贮藏生理及品质的影响

为保持鲜切哈密瓜贮藏品质和效果,将具有防腐、抑菌作用的柠檬烯用于鲜切哈密瓜的保鲜。用无菌蒸馏水、0.05%、0.10%、0.20%浓度的柠檬烯溶液对鲜切哈密瓜进行处理,放在5 ℃下贮藏,研究不同浓度的柠檬烯处理对鲜切哈密瓜生理及品质的影响。结果表明,0.10%柠檬烯处理可以较好地保持鲜切哈密瓜的水分、色泽,保持维生素C含量,减少可溶性固形物的消耗,抑制呼吸强度,减缓硬度下降的速率,提高超氧化物歧化酶（superoxide dismutase,SOD）活性,贮藏后期较好保持过氧化氢酶（catalase,CAT）活性,抑制多酚氧化酶（polyphenol oxidase,PPO）和过氧化物酶（peroxidase,POD）活性,减缓鲜切哈密瓜的代谢,较好地保持鲜切哈密瓜的品质。该试验得出柠檬烯处理鲜切哈密瓜有利于保持鲜切哈密瓜的贮藏品质且0.1%的柠檬烯处理液对鲜切哈密瓜的保鲜效果最佳。     

褪黑素处理对草莓品质与活性氧代谢的影响

本实验通过研究不同浓度（100、300、500 μmol/L）褪黑素（melatonin，MT）对草莓采后常温贮藏过程中腐烂程度、营养品质的影响，探讨了外源MT处理对‘ 红颜’草莓贮藏期间的保鲜效果。结果表明：3 个不同浓度的MT均能抑制草莓的腐烂，延缓果实硬度和可溶性固形物质量分数的下降，并维持抗坏血酸含量，其中300 μmol/L MT处理的效果最好。此外，还发现300 μmol/L MT在低温（4 ℃）下对草莓贮藏12 d内的抗氧化能力有明显提升：减缓丙二醛和过氧化氢的积累，抑制超氧阴离子自由基生成速率的上升，维持谷胱甘肽与抗坏血酸含量，维持超氧化物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶的活性并提高1,1-二苯基-2-三硝基苯肼自由基、2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸阳离子自由基和羟自由基清除率。因此，MT处理可成为延长草莓贮存寿命并维持其品质的有效保鲜方法。     

枫香叶精油对枇杷低温贮藏的防腐保鲜效果

为延长枇杷采后贮藏时间和维持果实品质,开发安全环保的生物源保鲜剂,用不同体积分数（1、 6 μL/100 mL和10 μL/100 mL）枫香叶精油对枇杷果实进行浸泡处理后,在5 ℃条件下贮藏30 d,每5 d测定腐烂指 数、质量损失率、硬度、可溶性固形物、木质素、丙二醛、过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）等果实 的品质和生理指标。结果表明,枫香叶精油可以显著延缓果实硬度上升和木质素的积累,减少果实腐烂、质量损失 和丙二醛含量,减缓可溶性固形物的降低,抑制POD和PAL的活性,在果品保鲜的应用领域有较好的前景,其中以 6 μL/100 mL精油处理的效果更好。     

2,4-表油菜素内酯对草莓果实贮藏品质及抗氧化活性的影响

以‘红颜’草莓为实验原料,研究2,4-表油菜素内酯（2,4-epibrassionolide,EBR）对草莓果实的贮藏品质 和抗氧化活性的影响。结果表明：5.0 μmol/L的EBR显著抑制草莓果实贮藏期间腐烂指数的上升（P＜0.05）。同时 EBR处理减少了果实硬度、可溶性固形物和VC含量的下降,增加了总酚、花色苷和类黄酮的积累量。EBR处理还 诱导草莓果实3 种抗氧化酶（超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化物酶）活力的增加,并抑制H2O2的积 累（P＜0.05）。研究表明EBR处理可提高草莓的耐贮性和贮藏品质,这可能与其维持草莓果实较高的抗氧化活性 有关。     

植物精油对草莓果实腐烂和品质的影响

以“丰香”草莓为试材,研究不同添加量(0.5、1、5、10μL/L)的香芹酚、肉桂醛、紫苏醛、沉香萜醇和异硫氰酸稀丙酯(AITC)处理对草莓果实常温和低温保鲜的效果。结果表明,五种植物精油都能显著抑制草莓果实在20℃和5℃贮藏期间腐烂的发生,其中以AITC处理的效果最好。但处理水平过高,即AITC和紫苏醛处理水平达到5μL/L、其他3种精油处理水平为10μL/L时,会对果实产生药害。采用适宜处理水平的各种植物精油处理还可显著抑制果实在5℃贮藏时质量损失率的上升和硬度的下降、保持较高的可滴定酸、可溶性固形物、VC、总糖和还原糖含量,从而保持果实品质。因此,植物精油处理在草莓果实防腐保鲜中具较好的应用前景。     

乙醛熏蒸处理对草莓贮藏品质的影响

研究了不同水平的乙醛熏蒸处理对草莓贮藏品质的影响,结果表明,草莓果实采收后立即用0.5％乙醛蒸汽处理1h,可以降低果实的腐烂率、减少失重、提高糖酸比、改善风味、增进着色、诱导香味和延缓采后软化;0.15％乙醛处理4h效果不明显;0.5％乙醛处理4h反而促进果实腐烂。     

柑橘精油对致草莓腐烂的菌种的抑菌效果研究

从自然腐烂的草莓中分离纯化得到两株革兰氏阳性细菌（标记为B1和B2）及一株青霉菌,研究了柑橘精油对这三种菌株的抑制效果,并分析了三种菌株的最低抑菌浓度,以及不同贮存时间和pH对柑橘精油的抑菌效果影响。结果表明,柑橘精油对细菌B1、B2和青霉菌均有抑制作用;柑橘精油对三种菌株的最低抑菌浓度为1.25%;贮存时间对柑橘精油的抑菌效果有一定影响,在贮存6 d后柑橘精油的抑菌作用趋于稳定;pH对柑橘精油的抑菌效果影响较大,最佳的作用pH值为5。     

硅藻土附载丁香酚缓释处理对不同品种草莓品质影响的比较

以4个品种草莓(晶瑶、晶玉、甜查理和宁丰)为试验材料,将丁香酚附载于硅藻土缓释,研究了不同品种、丁香酚缓释处理下草莓的保鲜效果。研究表明,晶瑶草莓贮藏保鲜效果优于晶玉、甜查理和宁丰三个品种草莓,货架期更长,保鲜品质由优至劣依次为:晶瑶、甜查理、宁丰、晶玉。在冷藏(4±1℃)过程中,丁香酚缓释可抑制草莓果实腐败,延缓果实质量损失和果肉可溶性固形物、可滴定酸、还原糖、Vc含量的降低,还能抑制MDA含量的上升以及SOD、POD、CAT等抗氧化酶类活性下降,对保持草莓果实的感官品质也具有积极作用;贮藏9 d时,经丁香酚缓释处理的晶瑶草莓腐烂率和失重率分别为31.50%和1.33%,可溶性固形物、可滴定酸、还原糖、Vc含量分别为8.83%、0.577%、5.72%和31.46 mg/100 g,MDA含量为23.11 nmol/g、SOD、POD、CAT活性分别、261.68 U/mL、1.65 U/mg、52.49 U/g。总而言之,硅藻土附载丁香酚缓释处理对草莓具有一定的保鲜作用,且不同品种草莓之间具有一定差异。     

Minimizing texture loss of frozen strawberries: effect of infusion with pectinmethylesterase and calcium combined with different freezing conditions and effect of subsequent storage/thawing conditions

Vacuum infusion (VI), freezing, frozen storage and thawing conditions were optimized in order to minimize the texture loss of frozen strawberries. Slow freezing caused severe loss in textural quality of the strawberries. This quality loss could not be prevented by the application of VI prior to slow freezing, or by the application of rapid, cryogenic or high-pressure shift freezing conditions on non-infused fruits. A remarkable texture improvement was noticed when infusion of pectinmethylesterase (PME) and calcium was combined with rapid or cryogenic freezing. The highly beneficial effect of PME/Ca-infusion followed by HPSF on the hardness retention of frozen strawberries was ascribed to the combined effect of the infused PME (53% reduction in degree of esterification (DE) of the strawberry pectin) and the high degree of supercooling during HPSF. During frozen storage, textural quality of PME/Ca-infused high-pressure frozen strawberries was maintained at temperatures below −8 °C, whereas the texture of PME/Ca-infused strawberries frozen under cryogenic freezing conditions was only preserved at temperatures below −18 °C. Thawing at room temperature seemed to be an appropriate method to thaw strawberries. Fast thawing by high-pressure induced thawing (HPIT) did not prevent textural quality loss of frozenstrawberries.     

柠檬烯复合液对草莓采后保鲜效果的影响

用柠檬烯复合溶液浸泡草莓3min,研究柠檬烯复合液对草莓贮藏期间各项营养指标的影响。结果表明,与对照相比,各处理均能明显减缓草莓果实中维生素C、可滴定酸和可溶性固形物含量的下降,抑制草莓的失水和腐烂,对草莓有较好的保鲜效果。     

Using survival analysis to investigate the effect of UV-C and heat treatment on storage rot of strawberry and sweet cherry

Ultraviolet light and heat treatment are proposed as alternative techniques for the use of chemicals to reduce the development of the spoilage fungi Botrytis cinerea and Monilinia fructigena on strawberry and sweet cherry, respectively, during storage. In order to investigate the effect of both physical techniques on microbial inactivation and on fruit quality, inoculated berries were subjected to different temperatures (40-48 degrees C) and UV-C doses (0.05-1.50 J/cm2). For each condition, 20 berries were used. After the treatment, fungal growth, visual damage (holes, stains) and fruit firmness were evaluated during a period of 10 days. The experimental data were analysed statistically using survival analysis techniques. Fungal growth on strawberries was significantly retarded using UV-C doses of 0.05 J/cm2 and higher. The same treatment had no significant effect when applied to cherries. The highest doses (1.00 and 1.50 J/cm2) had a negative effect on the calyx of the strawberry, causing browning and drying of the leaves. No beneficial effect of a low temperature treatment (40-48 degrees C) on the shelf life of strawberries was observed, but fungal development on cherries was retarded at temperatures of 45 and 48 degrees C. These temperatures caused severe damage on strawberries (soft stains, holes, decreased firmness), but had no influence on the quality of sweet cherries.     

草莓保鲜剂的开发研究

目的 探讨不同类型保鲜剂对草莓采摘后的保鲜效果。方法 将草莓置于蒸馏水、生姜提取液、甘草-壳聚糖溶液中浸泡1 min, 探讨保鲜剂对草莓感官、营养、生化指标等的影响。结果 与对照组相比, 2种保鲜剂都能显著抑制草莓失重、腐烂, 也能延缓维生素C和可滴定酸含量下降, 抑制超氧化物歧化酶和过氧化物酶活性损失, 但甘草-壳聚糖保鲜效果更好。贮藏6 d后, 甘草-壳聚糖组比空白对照组可滴定酸含量高72.90%, 维生素C含量高93.79%, 过氧化物酶活性高233.01%, 超氧化物歧化酶活性高187.47%。结论 甘草-壳聚糖作为保鲜剂, 能有效地延长草莓贮藏期。     

Natural volatile treatments increase free‐radical scavenging capacity of strawberries and blackberries

Free‐radical scavenging capacities of strawberries and blackberries treated with methyl jasmonate (MJ), allyl isothiocyanate (AITC), essential oil of Melaleuca alternifolia (tea‐tree oil or TTO), and ethanol (EtOH) were investigated. All of these natural volatiles tested reduced the severity of decay in both strawberries and blackberries during storage at 10 °C as compared to the control. Most of these compounds enhanced antioxidant capacity and free‐radical scavenging capacity, except the AITC treatment. The MJ treatment for strawberries and blackberries had the highest antioxidant capacity, expressed as oxygen radical absorbance capacity (ORAC) values, after 7 days of storage. Moreover, the MJ treatment promoted the antioxidant capacity in strawberries and blackberries as measured by the radical 2,2‐di (4‐tert‐octylphenyl) ‐1‐picrylhydrazyl (DPPH) and the radical cation 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS^?+) scavenging activity in both 7 and 14 days after storage. The MJ treatment also increased scavenging capacities on the superoxide radical (O₂^??), hydrogen peroxide (H₂O₂), hydroxyl radical (^?OH), and singlet oxygen (¹O₂) in strawberries and blackberries. Treatment with TTO or EtOH enhanced most of these free‐radical scavenging capacities, except for H₂O₂ in strawberries, and for O₂^?? and ¹O₂ in blackberries. These results indicated that all of the natural volatile compounds tested in this study, except AITC, promoted the antioxidant capacity and scavenging capacity of most major free radicals and, thus, helped to improve the physiology of berry fruits and enhanced their resistance to decay. While AITC was also very effective in reducing decay, its effect on free‐radical scavenging capacity was inconsistent, suggesting that additional mechanisms may be involved in its inhibition of fungal growth. Copyright © 2007 Society of Chemical Industry