茉莉酸甲酯熏蒸提高树莓果实采后贮藏品质

树莓果实为材料,研究了茉莉酸甲酯(methyl jasmonate,MJ)熏蒸对树莓果实采后贮藏期间硬度(firmness)、可溶性固形物(total soluble solid,TSS)、可滴定酸(titratable acid)和抗坏血酸(ascorbic acid)含量和总酚含量的影响。结果表明,茉莉酸甲酯熏蒸可以有效的维持树莓贮藏期间的硬度,减缓树莓果实中可溶性固形物、可滴定酸和抗坏血酸含量的下降,提高树莓果实贮藏期间总酚含量的上升,较好的保持了树莓果实的品质。贮藏结束后,茉莉酸甲酯处理组果实的硬度、可溶性固形物、可滴定酸和抗坏血酸含量和总酚含量分别比对照组高9.6%、22.3%、21.2%、23.1%和3.3%,这说明茉莉酸甲酯熏蒸可以提高树莓果实的采后贮藏品质。     

臭氧处理对采后黄瓜贮藏品质的影响

目的研究不同浓度臭氧处理对采后黄瓜贮藏品质的影响。方法分别用浓度为1、3和5μg/mL臭氧处理用微孔膜包装的黄瓜15 min,每隔1 d处理1次,于7℃冷库中贮藏,并通过测定黄瓜硬度、可溶性固形物、可滴定酸、维生素C、叶绿素、丙二醛、过氧化物酶活性等指标来确定处理黄瓜的合适臭氧浓度。结果与对照组相比,采用5μg/mL浓度的臭氧处理可保持黄瓜较好的硬度,减缓叶绿素、抗坏血酸、可滴定酸和可溶性固形物等营养成分的降低,有效抑制丙二醛的积累,抑制过氧化物酶的活性。结论臭氧处理可以保持黄瓜的生理生化指标,提高黄瓜的贮藏品质,其中5μg/mL的臭氧处理效果最好。     

毛花猕猴桃“华特”果实采后生理和品质变化研究

以毛花猕猴桃“华特”品种为试材,研究常温20℃条件果实采后品质变化规律。结果表明：采后果实硬度和可滴定酸含量在贮藏前期急剧下降,而后稳定;呼吸强度、可溶性固形物、维生素C和还原糖含量在贮藏前期逐渐增加,贮藏后期下降;总酚和类黄酮含量变化不大。     

不同保鲜剂对米枣采后贮藏品质的影响

探索不同保鲜剂对米枣贮藏过程中品质指标的影响。以绵阳“米枣”为试材,采后用复合保鲜剂涂膜、壳聚糖涂膜和1-MCP处理后,置于温度(4±1)℃的冷藏库贮藏,测定贮藏过程中转红率、腐烂率、质量损失率、硬度、VC、可溶性糖、可滴定酸和可溶性固形物等各项品质指标的变化。结果表明：与对照组相比,处理组能不同程度的保持米枣的硬度,延缓成熟进程和品质下降。复合保鲜剂处理组贮藏至30d时,硬度为13.54kg/cm2,转红率、腐烂率和质量损失率分别为69%、16.3%和1.21%,VC含量为270mg/100g,可溶性糖含量、可滴定酸含量和可溶性固形物含量为14.1%、0.2%和20%,各项品质指标均优于其他处理组和对照组。     

不同贮藏温度对杏梅贮藏品质的影响

本实验以杏梅果实为供试材料,采用不同贮藏温度(0、2、4、6℃),以杏梅果实腐烂率、失重率、可溶性固形物含量、可滴定酸含量等为参考指标,研究贮藏温度对杏梅果实采后贮藏期间品质的影响。结果表明:不同贮藏温度对杏梅贮藏品质的影响效果不同。与4℃和6℃贮藏相比,0℃和2℃可以显著降低杏梅果实贮藏期间腐烂率和失重率,同时较好地维持杏梅果实贮藏期间的硬度、可溶性固形物含量(TSS)、可滴定酸含量(TA),也有效抑制了杏梅果肉总酚含量和VC含量的下降,使其抗氧化活性保持在较高水平。     

一氧化氮处理对杏果实贮藏品质的影响

以硝普钠(SNP)为一氧化氮供体,研究了不同浓度NO处理对兰州"大接杏"采后贮藏品质的影响。结果表明,采后适当浓度的SNP浸泡处理可显著降低"大接杏"果实贮藏期间的腐烂率,延缓了果实可溶性固形物(SSC)含量的增加,可滴定酸含量、硬度和Vc含量的下降,可溶性果胶含量的升高以及色泽的转变,较好地维持果实的贮藏品质,其中以1mmol/L的SNP处理作用效果最佳。     

水杨酸处理对杏果实贮藏品质的影响

研究了水杨酸处理赛买提杏后对其采后贮藏品质的影响。在0.05MPa负压下,将杏果实分别浸泡于浓度为0.002、0.01、0.05g/L的水杨酸溶液中。将处理后的杏果实取出晾干,于4℃,RH90%～95%条件下贮藏。定期测定杏果实贮藏期间的失重率、硬度、叶绿素、维生素C、可溶性固形物、可滴定酸、发病率。结果显示,0.01g/L水杨酸处理的杏果实贮藏品质最好,能有效地抑制杏果实贮藏期间的失重率上升,硬度的下降,延缓叶绿素和维生素C含量的下降,减少杏果实中可溶性固形物和可滴定酸的损耗,降低杏果实腐烂率。     

贮藏温度对“宁海白”和“大红袍”枇杷果实品质的影响

研究不同贮藏温度(0℃和25℃)对红肉枇杷“大红袍”和白肉枇杷“宁海白”果实贮藏期间果实可溶性固形物、可滴定酸、出汁率、相对电导率、总酚和木质素含量的影响。结果发现,枇杷果实采后贮藏期间可溶性固形物和可滴定酸含量减少,果肉出汁率快速下降,果实贮藏品质发生劣变。低温(0℃)贮藏可维持较高含量的 可溶性固形物和可滴定酸含量,却促进贮藏后期总酚含量的减少和木质素的积累,导致果实木质素败坏的发生,降低了果实的食用品质。在25℃贮藏期间,枇杷果实木质素含量也呈增加趋势。表明枇杷果实采后木质化败坏是一种衰老现象,不适当的低温贮藏会加剧这种衰老现象的发生。     

不同贮藏温度对采后86-1哈密瓜果实冷害及品质的影响

为了研究不同贮藏温度对采后哈密瓜果实冷害及品质的影响,分别对1、3、5℃贮藏条件下86-1哈密瓜果实的冷害症状、冷害指数、冷害率、细胞膜相对透性、硬度、可溶性固形物含量、可滴定酸及维生素C含量进行了系统观察、统计与测定。结果表明:86-1哈密瓜冷害的发生与贮藏温度及持续时间有关,1℃贮藏条件下,86-1哈密瓜果实冷害出现的时间较早,果实的冷害指数、冷害率及细胞膜相对透性较高;硬度、可溶性固形物及维生素C含量下降较快,可滴定酸出现先上升后下降的趋势。3℃贮藏有利于维持86-1哈密瓜果实的品质,5℃贮藏果实虽未发生冷害,但后期品质劣变较快,腐烂较重。     

电子束辐照对不同品种猕猴桃品质的影响

以4 个品种（‘海沃德’‘徐香’‘华优’‘亚特’）猕猴桃为试材,采用剂量分别为0.4、0.8、1.2 kGy的高能电子束辐照处理,于0～1 ℃、相对湿度90%～95%条件下贮藏,每15 d取样一次,测定电子束辐照处理对果实冷藏期硬度、质量损失率、可溶性固形物质量分数、可滴定酸质量分数、VC含量等品质指标的影响,探究电子束辐照对猕猴桃贮藏品质的影响,为猕猴桃采后保鲜技术提供理论依据。结果表明,电子束辐照处理对维持猕猴桃的贮藏品质有一定积极作用。适宜剂量电子束辐照能抑制猕猴桃贮藏期间果实的质量损失,延缓可滴定酸质量分数的下降,提高类黄酮含量,在贮藏前期提升多酚含量,但硬度、VC含量经辐照后有所降低,且可溶性固形物质量分数升高。相比其他剂量,0.8 kGy电子束辐照能够较好地延缓猕猴桃可溶性固形物质量分数升高和可滴定酸含量降低,提高多酚和类黄酮的含量。整体来看,4 个品种中‘海沃德’‘亚特’更加耐受电子束辐照,且0.4、0.8 kGy剂量的电子束辐照对‘海沃德’‘亚特’的采后贮藏保鲜效果较好,推荐0.4、0.8 kGy为‘海沃德’‘亚特’的采后保鲜辐照剂量。结论：适宜剂量的电子束辐照可以作为提升猕猴桃保鲜效果的有效手段。     

核桃青皮提取液与壳聚糖复合物对甜瓜采后品质的影响

利用核桃青皮提取液与壳聚糖复配制备出一系列不同配比的复合物溶液,应用于新疆甜瓜的保鲜实验。分析3 种不同配比复合物溶液对甜瓜采后贮藏品质及生理指标的影响。结果表明,在温度25 ℃、相对湿度55%～60%条件下,核桃青皮提取液-壳聚糖复合物能够有效地降低甜瓜的发病率、质量损失率和呼吸强度,减少甜瓜中可溶性固形物和可滴定酸含量的降低,促进多酚氧化酶和过氧化物酶的活性,保持甜瓜中苯丙氨酸解氨酶的活性,但其对甜瓜硬度的影响不明显。核桃青皮提取液含量较高的CHE-25复合物溶液在甜瓜采后贮藏多个生理指标和酶活性等因素上表现均优于其他组,其保鲜作用效果最优,说明核桃青皮提取物可作为天然保鲜剂应用于甜瓜采后贮藏保鲜。     

Control of anthracnose rot and quality deterioration in loquat fruit with methyl jasmonate

BACKGROUND: Loquat (Eriobotrya japonica Lindl.) fruit has a short shelf‐life, mainly due to fungal decay. Current control of postharvest disease of the fruit is mainly dependent on fungicides. However, because of the increasing consumer concern over food safety, there is an urgent need to search for effective alternatives to control disease. The objective of this work was to determine the efficacy of methyl jasmonate (MeJA) in controlling anthracnose rot caused by Colletotrichum acutatum and maintaining quality of loquat fruit. RESULTS: Loquat fruit were treated with 10 µmol L^?1 MeJA and wound inoculated with C. acutatum spore suspension of 1.0 × 10⁵ spores mL^?1 24 h after treatment, and then stored at 20 °C for 6 days. The percentage of infected wounds showing decay symptom was reduced from 54.4% to 16.7% and the lesion diameter was reduced from 7.26 mm to 4.00 mm by MeJA treatment on the 4th day after inoculation. MeJA treatment induced higher activities of two defense‐related enzymes—chitinase and β‐1,3‐glucanase—during 6 days storage. Meanwhile, the treatment inhibited increases in fruit firmness and internal browning index, and maintained higher extractable juice rate and total soluble solids and titratable acidity contents, thereby delaying the development of flesh leatheriness. CONCLUSION: MeJA treatment effectively inhibited anthracnose rot and maintained quality in loquat fruit. Inhibition of the disease was mainly because of resistance induced in loquat fruit by MeJA. A postharvest application of MeJA could be an alternative to chemical fungicides for control of postharvest disease in loquat fruit. Copyright © 2008 Society of Chemical Industry     

低氧贮藏对采后果实风味的影响研究进展

低氧是传统气调贮藏技术中采用的主要措施之一,可显著延长果实的贮藏期和缓解其采后生理紊乱症状。在气调贮藏期间,低氧环境可降低果实呼吸作用,减少乙烯的生物合成,延缓果实的成熟和衰老,更好地维持果实硬度、可溶性固形物、可滴定酸度、抗坏血酸含量等品质指标水平。然而,一般认为低氧会对果实的风味品质造成一定程度的负面影响。本文综述果实气调贮藏过程中低氧对其主要糖分、有机酸和挥发性香气组分生物合成的影响,并对其生化和分子机制进行了阐述,以期为改善气调贮藏果实的风味品质提供理论参考。     

Biocontrol of Postharvest Anthracnose of Mango Fruit with Debaryomyces Nepalensis and Effects on Storage Quality and Postharvest Physiology

Anthracnose is presently recognized as one of the most important postharvest disease of mango worldwide. To control the disease, chemical fungicides for a long time was widely used among fruit farmers, but recently found that pathogen had developed increasingly resistance to it. With people's growing desire of healthy and green food, finding new and environmentally friendly biological control approach was very necessary. In this paper, we provided a kind of new antagonistic yeast which enriched the strain resources and the efficacy of Debaryomyces nepalensis against postharvest anthracnose of mango fruit and the influence on quality parameters were investigated. The results showed that the decay incidence and lesion diameter of postharvest anthracnose of mango treated by D. nepalensis were significantly reduced compared with the control fruit stored at 25 °C for 30 d or at 15 °C for 40 d, and the higher concentration of D. nepalensis was, the better the efficacy of the biocontrol was. Study also found that 1 h was the best treatment duration and antagonistic yeast inoculated earlier had good biocontrol effect on anthracnose. Meanwhile, treatment by D. nepalensis could significantly reduce postharvest anthracnose of mango, delay the decrease in firmness, TSS, TA, and ascorbic acid value, and do not impair surface color during postharvest storage. Moreover, the increase in MDA (malondialdehyde) content and increase in cell membrane permeability of fruit treated by D. nepalensis was highly inhibited. The results suggested D. nepalensis treatment could not only maintain storage quality of mango fruit, but also decrease the decay incidence to anthracnose disease. All these results indicated that D. nepalensis has great potential for development of commercial formulations to control postharvest pathogens of mango fruit.     

Effect of 1‐methylcyclopropene on anthracnose rot caused by Colletotrichum acutatum and disease resistance in loquat fruit

BACKGOUND: Loquat (Eriobotrya japonica Lindl.) fruit are susceptible to fungal decay during postharvest storage at ambient temperature. The control of postharvest diseases of loquat is based primarily on the use of synthetic fungicides. To look for an alternative method for disease control, we investigated the effect of 1‐methylcyclopropene (1‐MCP) on controlling anthracnose rot caused by Colletotrichum acutatum of loquat fruit. RESULTS: 1‐MCP treatment significantly reduced decay incidence of loquat fruit. The treatment markedly inhibited accumulation of superoxide radicals and hydrogen peroxide and maintained higher superoxide dismutase, catalase and ascorbate peroxidase. Meanwhile, 1‐MCP treatment induced higher activities of two defense‐related enzymes—chitinase and β‐1,3‐glucanase—during 6 days' storage. Furthermore, the treatment inhibited increases in fruit firmness and internal browning index, and maintained higher extractable juice rate, total soluble solids and titratable acidity contents, thereby delaying the development of senescence. CONCLUSION: 1‐MCP was effective in reducing decay and might have enhanced the disease resistance in loquat fruit by increasing chitinase and β‐1,3‐glucanase, and maintained natural resistance by delaying senescence development. Copyright © 2010 Society of Chemical Industry     

采后热处理对黄瓜颜色变化的影响

为了探索采后热处理对黄瓜颜色的影响,以"津优10"黄瓜为试材,对黄瓜进行了不同温-时组合的热处理实验,测定了黄瓜在Hunter表色系统下亮度L、红绿度a、黄蓝度b、色泽角H°、饱和度C及色差△Eab变化,并对各颜色指标变化进行了统计学及动力学分析。结果表明,热处理黄瓜的最佳颜色评价指标是L或△Eab,热处理时间比热处理温度对两个颜色指标的影响更显著,黄瓜的失水率与L呈显著的负相关关系,但与△Eab呈显著正相关关系,热处理黄瓜的L及△Eab在贮藏期间的变化分别符合一级与零级化学反应动力学模型。相关结论可为黄瓜采后热处理的工艺优化及品质预测提供参考。     

Chitosan-limonene coating in combination with modified atmosphere packaging preserve postharvest quality of cucumber during storage

Since cucumbers suffer from a short postharvest life, applying different technologies is increasingly used as effective ways to increase their shelf life and quality. In this study a combination of chitosan-limonene coating and MAP storage has been used as a postharvest treatment to maintain cucumber quality. Samples were stored in three different packages: A (21% O₂, macro-perforated package to be in equilibrium with air); package B (active MAP, starting concentrations 10% O₂?+?5% CO₂); package C (passive MAP starting concentrations 21% O₂?+?0.1% CO₂); they were stored at three temperatures (20, 10, and 4 °C). Quality parameters of cucumber such as weight loss, firmness, color, pH, fungal growth, T_g, organoleptic properties were determined. Interactive effects of coating, package, temperature, and storage time showed that coating and MAP in general had positive effects on several quality aspects. Coating combined with active MAP had the most positive effect on most postharvest attributes. However, using active MAP at higher temperature led to quality problems and is only useful if storage time is short. The combined usage of active MAP and chitosan-based coating on cucumber represents an innovative and interesting method for commercial application.     

复合菌株对采后芒果品质和抗病性的影响

以实验室分离得到的汉逊德巴利酵母（Debaryomyces hansenii,Y-1）、尼泊尔德巴利酵母（Debaryomyces nepalensis,T18）和萎缩芽孢杆菌（Bacillus atrophaeus,TE-7）为材料,研究单独处理（Y-1、T18、TE-7）和复合处理（Y-1＋TE-7、Y-1＋T18、T18＋TE-7）对芒果贮藏品质和抗病性的影响。结果表明：Y-1和TE-7菌悬液以体积比1∶1复配后浸泡芒果20 min,能显著抑制胶胞炭疽菌（Colletotrichum gloeosporioides）孢子萌发;此外,与Y-1和TE-7单一处理相比,Y-1＋TE-7处理能有效延缓果实a*值、可溶性固形物质量分数、硬度、可滴定酸质量分数的变化;贮藏中后期（6 d后）,Y-1＋TE-7处理较Y-1和TE-7单一处理过氧化物酶、苯丙氨酸解氨酶、β-1,3-葡聚糖活力增强;贮藏中期（9～18 d）,Y-1＋TE-7处理较Y-1和TE-7单一处理多酚氧化酶活力减弱。说明Y-1和TE-7复合使用能显著提高采后芒果的贮藏品质,增强果实的抗病性,在芒果采后处理上具有一定的应用潜力。     

低温贮藏下木纳格葡萄适宜UV-C照射剂量的筛选

以新疆木纳格葡萄为原料,在CK对照组和3个不同剂量(0.4、1.2和2 kJ/m2)UV-C照射,贮藏于-1 ℃环境中,研究四种处理对木纳格葡萄可溶性固形物、可滴定酸含量呼吸强度、腐烂率落粒率、好果率等采后贮藏品质的影响。结果表明:采用1.2 kJ/m2 UV-C间隔性(15 d)照射的木纳格葡萄,贮藏期结束保持7.7%的低腐烂率,落粒率为12.51%,好果率为86.6%,同时保持较高的可溶性固形物和可滴定酸含量,分别为16.54%和0.37%,更好地保持了果实的品质。     

黄瓜细菌性萎蔫病菌分子诊断研究

从田间黄瓜细菌性萎蔫病植株分离获得病原菌,比对其近源种的16S rDNA序列,确定该病原菌为嗜维管束欧文氏菌(Erwinia tracheiphila),并设计出特异引物ET-P1/ET-P2.经过对该引物的PCR扩增条件优化,扩增出一条794 bp的黄瓜细菌性萎蔫病菌特异条带,检测灵敏度达100 fg/μL,可准确扩增出黄瓜发病植株和根围土壤中的DNA片段.