采后UV-C照射对芦柑抗病性和品质的影响

研究不同剂量UV-C照射处理对采后芦柑在15℃贮藏期间腐烂率及主要品质指标的影响。结果表明,1.5kJ/m2或3kJ/m2UV-C照射能有效减轻果实贮藏期间腐烂,推迟腐烂6d或12d,显著降低腐烂率。贮藏后期,1.5kJ/m2或3kJ/m2处理降低了失重率,提高了果实的可溶性固形物含量、糖酸比和VC含量,且促进了果肉中类黄酮和总酚的次生代谢合成,从而较好地保持了果实的感官品质和营养品质。1.5kJ/m2或3kJ/m2处理也有助于提高果皮中类黄酮和总酚含量。UV-C照射处理作为采后芦柑的非化学贮藏保鲜手段,具有潜在的应用前景。     

氧化亚氮(N_2O)熏蒸对木纳格葡萄贮藏品质的影响

木纳格葡萄品质优良,但采后果实易出现失重软化、落粒以及果梗褐变等问题。为了探究小分子气体氧化亚氮(Nitrous oxide,N_2O)熏蒸对鲜食葡萄采后贮藏品质的影响。以新疆特色鲜食葡萄木纳格葡萄(Vitis vinifera L.cv.Munage)为试材,采用20、50和100μL/L的N_2O对木纳格葡萄进行间歇熏蒸处理(每7 d),在(0±0.5)℃的条件下贮藏70 d。测定了贮藏过程中木纳格葡萄的腐烂率、落粒率、失重率、硬度、可滴定酸、可溶性固形物、电导率、抗坏血酸过氧化物酶(Aseorbate peroxidase,APX)以及过氧化物酶(Peroxidase,POD)的变化。结果表明:50μL/L的N_2O熏蒸能保持可溶性固形物、可滴定酸的含量;有效抑制果实腐烂率、落粒率及相对电导率的上升,降低过氧化物酶和抗坏血酸过氧化物酶的活性,保持了较好的果实硬度,说明N_2O熏蒸能够延缓木纳格葡萄果实采后的衰老进程,较好的维持木纳格葡萄的采后品质。     

一氧化氮间歇熏蒸对木纳格葡萄贮藏品质的影响

以木纳格葡萄为试验材料,采用不同浓度的一氧化氮(Nitric oxide,NO)对新疆木纳格葡萄进行间歇熏蒸处理。测定了贮藏期的可溶性固形物、可滴定酸和抗坏血酸等品质指标的变化趋势,分析NO间歇熏蒸方式对木纳格葡萄采后品质的影响。结果表明:与对照和其他浓度NO处理组相比,300μL/L NO显著延缓了木纳格葡萄可溶性固形物含量、可滴定酸含量和抗坏血酸含量的下降;延缓了果肉的软化以及叶绿素的降解;抑制了果实失重率、腐烂率、落粒率和果梗褐变指数的增长。适宜浓度的NO处理可延缓采后木纳格葡萄果实的衰老和维持果实的贮藏品质。     

低温贮藏结合SO_2保鲜剂对无核白葡萄保鲜效果研究

以新疆无核白葡萄为试材,研究了在不同贮藏温度(0、-1℃)下CT-2、CT-5保鲜剂处理的葡萄果实品质变化。结果表明:低温配合保鲜剂处理能有效抑制果穗呼吸,减少葡萄贮藏期间的腐烂率、落粒率、果穗失重率,延缓果实贮藏过程中可溶性固形物、可滴定酸含量的下降,使果梗耐拉力保持较高水平。其中-1℃结合保鲜剂贮藏能够减轻果实漂白伤害,贮藏70 d的漂白率为2.69%,好果率也显著高于其余处理,为88.15%(p0.05),处理效果更好。综上所述,-1℃结合保鲜剂处理能够有效延长无核白葡萄贮藏期,保持果实品质。     

赤霉素处理对两种葡萄品质和贮藏生理的影响

以红地球葡萄和克瑞森无核葡萄为试材,研究采前使用赤霉素（GA₃）处理对果实采收时的品质及采后贮藏特性的影响,测定贮藏期间果实的腐烂率、落果率、呼吸速率、果实硬度、可溶性固形物含量、可滴定酸含量和丙二醛含量等生理指标。结果表明:采前使用30mg/L GA₃处理可使采收时红地球葡萄和克瑞森无核葡萄果实单粒质量分别提高29.33%和32.30%,平均单穗质量分别增加49.71%和33.36%,在果实冷藏期间,能有效控制葡萄的腐烂和落粒,显著抑制红地球葡萄和克瑞森无核葡萄果实在贮藏过程中的呼吸速率,有效地维持果实硬度,减少可滴定酸的下降幅度,保持葡萄的营养成分,延缓果实丙二醛的生成,保持细胞膜的完整性。     

冰温结合CT-2保鲜剂对玫瑰香葡萄贮藏品质及生理的影响

以玫瑰香葡萄为试材,通过对不同处理方式的果实在贮藏期间品质和生理生化指标的变化规律分析,探讨冰温贮藏结合CT-2保鲜剂处理对果实的保鲜效果。结果表明:冰温贮藏结合CT-2保鲜剂处理减轻了葡萄贮藏过程中的失重率、落粒率和腐烂率,降低了葡萄在贮藏过程中可溶性固形物、可滴定酸、Vc含量的损失,较好地保持了葡萄的品质;减缓了丙二醛含量的增长速度,有效延缓了葡萄在贮藏过程中的衰老进程;POD、SOD活性较单纯冰温贮藏有所增加,减少自由基的积累,从而延长了贮藏时间。     

采后短波紫外线处理对苹果耐贮性和品质的影响

以红富士苹果为试材,研究7.5 kJ/m2剂量短波紫外线（ultraviolet-C,UV-C）处理对苹果常温和低温条件下贮藏性和品质的影响。供试苹果经7.5 kJ/m2 UV-C照射后,分别贮藏在20 ℃和0 ℃条件下,定期测定果实质量损失率、呼吸强度、硬度、可溶性固形物含量（soluble solids content,SSC）、可滴定酸含量、超氧化物歧化酶（superoxide dismutase,SOD）活性及丙二醛（malondialdehyde,MDA）含量。结果表明,不论是常温还是低温条件下,整个贮藏过程中,UV-C处理组果实质量损失率、呼吸强度均较对照低;果实硬度、可滴定酸含量呈下降趋势,但处理组高于对照组;SSC整体呈先上升后下降趋势,但处理组较对照组下降缓慢;SOD活性总体呈先上升后下降趋势,但UV-C处理组活性始终高于对照组;果实MDA含量均呈上升趋势,但处理组上升缓慢。可见,采后苹果经适宜剂量UV-C照射能减轻质量损失,降低呼吸强度,减缓果实硬度、SSC及可滴定酸含量下降,保护膜完整性,延缓衰老,对保障品质,延长贮藏保鲜期有良好效果。     

缓释保鲜纸对无核白葡萄采后贮藏品质的影响

为延长葡萄的保鲜时间,以无核白葡萄为试验材料,在果实包装中放入8种缓释保鲜纸进行处理(CT1～CT8),以空白组(CK)和2种市售葡萄保鲜纸组别(市售Ⅰ、市售Ⅱ)为对照,在温度为(0±1)℃、相对湿度为80%的条件下贮藏55 d,测定样品的腐烂率、落粒率、果梗褐变指数、pH值、质量损失率、可滴定酸含量及可溶性固形物含量、硬度及SO₂残留量。结果表明,与空白组及市售Ⅰ、市售Ⅱ组别相比,贮藏55 d时,CT3处理组无核白葡萄果实腐烂率、落粒率与果梗褐变指数最低,分别为11.47%、10.78%、10.43%;该组别无核白葡萄pH值、质量损失率、可滴定酸及可溶性固形物含量、硬度均较优,分别为3.38、0.20%、0.85 g/L、14.0%、3.87 N;该组别SO₂残留量最低(34.5 mg/kg)。     

茶多酚处理对玫瑰香葡萄保鲜效果的研究

采用不同浓度的茶多酚对新鲜的玫瑰香葡萄进行喷涂处理,（20+1）℃放置,每隔2 d测定其硬度、腐烂率、失重率、可滴定酸含量、维生素C（VC）含量、可溶性固形物含量等品质指标,研究其对玫瑰香葡萄货架品质的影响。结果表明：一定浓度的茶多酚溶液处理可以降低果实腐烂率、失重率,延缓可溶性固形物含量、硬度值、可滴定酸以及维生素C含量的降低,浓度为1.5%和2.0%茶多酚溶液处理组可较好地保持葡萄果实的品质。     

短波紫外线照射和60Co-γ辐照处理对大樱桃贮藏品质的影响

为探究不同射线辐照处理对大樱桃果实保鲜效果的影响,采用不同剂量短波紫外线（short-wave ultraviolet light,UV-C）照射（1.37、2.05、2.74 kJ/m2）和60Co-γ辐照（0.75、1.5、2.25 kGy）分别处理大樱桃果实,定期检测其冷藏期间生理品质指标和果皮超微结构变化。结果表明：贮藏15 d内,1.37 kJ/m2照射和0.75 kGy辐照较对照组可显著延缓大樱桃果实好果率下降、抑制果实质量损失,较好保持果实质地特性,促进花青素合成,有效抑制过氧化物酶与超氧化物歧化酶活性下降,但对可溶性固形物含量影响不大,且会引起丙二醛含量增加。由于两种处理对好果率、硬度、质量损失率、花青素等感官品质核心指标具有良好的积极作用,因此对丙二醛的不利变化并不足以影响到果实的商品品质评价。电子显微镜结果显示,大樱桃经1.37 kJ/m2照射和0.75 kGy辐照处理后,与对照组相比,能在一定程度上减轻果皮细胞膜、线粒体、叶绿体等细胞结构的损伤程度,显著延缓果皮细胞衰老。此外,在贮藏前期与末期,1.37 kJ/m2照射和0.75 kGy辐照所发挥的作用并不相同。针对于5 d以内的短期贮藏,可采用1.37 kJ/m2 UV-C照射,而长期贮藏则以0.75 kGy 60Co-γ辐照效果更好。     

1-MCP对木纳格葡萄的保鲜效果

为寻找新型、无硫的鲜食葡萄保鲜方法,以新疆木纳格葡萄为试材,研究0.5、1.0和1.5 μL/L的1-MCP熏蒸处理对其在常温(25±0.5) ℃和冷藏(0~3) ℃贮藏期间果实的主要品质、生理指标及其作用效果的影响。结果表明:1-MCP熏蒸处理能在不同程度上降低常温贮藏条件下以及冷藏条件下葡萄的脱粒率、腐烂率、果穗失重率和果梗褐变,保持葡萄的硬度、可溶性固形物、V_C含量、可溶性糖含量以及可滴定酸含量。室温贮藏结束时,1.0 μL/L浓度1-MCP处理的葡萄可溶性糖含量为10.18%,比对照组高出29.36%,可溶性固形物比对照组高出20.65%,而失重率却比对照组低34.85%。冷藏贮藏结束时,1.0 μL/L浓度1-MCP处理的葡萄腐烂率为26.13%,比对照组低30.49%,而V_C含量比对照组高出34.38%。0.5 μL/L和1.5 μL/L的1-MCP处理对维持果实品质也有一定的作用,但是效果均不如1.0 μL/L处理的果实明显。综上所述,1.0 μL/L浓度的1-MCP处理的葡萄腐烂率最低,果实的外在品质和内在品质下降幅度最小,保鲜效果最好。     

Effects of preharvest application of antagonistic yeast combined with chitosan on decay and quality of harvested table grape fruit

BACKGROUND: Decay caused by fungal pathogens is responsible for significant economic loss of grape fruit in vineyards worldwide. However, postharvest treatment is not advisable for this fruit owing to its thin waxy pericarp and succulent flesh, which are easily damaged. Therefore preharvest treatment even at 1 day before harvest has been considered as a promising method to control postharvest decay of table grape fruit in storage. Integrative effects of preharvest application of Cryptococcus laurentii combined with low‐concentration chitosan on decay and quality of table grape fruit during storage were investigated in this study. RESULTS: Spraying of antagonistic yeast combined with chitosan before harvest significantly reduced natural decay of fruit stored at 0 °C. Preharvest treatment stabilised polyphenol oxidase activity, increased peroxidase and phenylalanine ammonia‐lyase activities and decreased superoxide dismutase activity compared with control fruit. There was a higher ratio of soluble solid content to titratable acidity in treated fruit than in control fruit during storage. In addition, preharvest treatment affected the total phenolic content in fruit during storage. CONCLUSION: The results suggest that integrative application of C. laurentii and low‐concentration chitosan before harvest may be a promising technology to control decay of table grape fruit in storage. Copyright © 2009 Society of Chemical Industry     

Photochemical Treatment to Improve Storability of Fresh Strawberries

We investigated the effect of pre-storage exposure to shortwave ultra-violet (UV-C) light on the decay and quality of fresh strawberries. Fresh strawberries (cv. Kent, 25% to 50% red) were exposed to UV-C at doses of 0.25 and 1.0 kJ/m² and stored at 4 °C or 13 °C. UV treatment controlled the decay caused by Botrytis cinerea at both temperatures and extended the shelf-life of the fruits by 4 to 5 d. UV-treated fruits had a lower respiration rate, higher titratable acidity and anthocyanin content, and were firmer than the untreated fruits. The percentage of free sugars increased faster in UV-treated fruits at the beginning of the storage period. A lower electrical conductivity in fruits treated with 0.25 kJ/m² suggests a slower rate of senescence compared to the control. A higher electrical conductivity observed with 1.0 kJ/m²suggests damage to the fruits. Overall, UV treatment at 0.25 kJ/m² appears to slow down the ripening and senescence of strawberry fruits stored at 4 °C.     

采前涂膜处理对宣化牛奶葡萄贮藏生理及品质的影响

研究采前涂膜处理对宣化牛奶葡萄的采后贮藏生理及保鲜效果。经采前挂蔓涂膜处理的牛奶葡萄在0℃条件贮藏100d,贮藏期间测定了果实的呼吸强度、乙烯释放量、总酚含量、叶绿素含量、可滴定酸含量等生理和品质指标。结果表明：采前涂膜处理可以显著抑制宣化牛奶葡萄果实在贮藏过程中的呼吸强度,处理组果实的呼吸强度比对照低42.5%～53.8%、并在一定程度上减少果实的乙烯释放量;采前涂膜能有效控制葡萄腐烂,贮藏结束时(100d)对照组腐烂率达75.3%,而涂膜处理组的腐烂率只有5.2%。同时可以减少褐变,贮藏75d时处理组的褐变指数比对照低81.6%。保持果实鲜绿色,处理组果实果皮叶绿素含量在50d和75d时为0.04mg/g和0.33mg/g,而对照组则为0.02mg/g和0.015mg/g;也可以保持葡萄果实可溶性固形物、可滴定酸含量,保持感官品质,延长保鲜期约50d。     

UV-C处理对杨梅采后品质及苯丙烷类代谢的影响

以“东魁”杨梅果实为材料,研究不同剂量的短波紫外线（UV-C）照射处理对杨梅果实采后品质、抗氧化活性、苯丙烷类代谢产物含量和相关酶活性的影响。杨梅果实先用0、1.5、3.0、4.5、6.0 kJ/m2剂量的UV-C照射处理,然后转入5 ℃贮藏12 d。结果表明,3.0 kJ/m2 UV-C处理显著地抑制了杨梅果实贮藏期间腐烂的发生,延缓了果实硬度和VC含量的下降,保持了果实品质;UV-C处理还显著提高了果实中苯丙氨酸解氨酶、4-香豆酰辅酶A连接酶、查尔酮异构酶和肉桂醛羟化酶等苯丙烷类代谢相关酶的活性,增加了总酚、花色苷、胡萝卜素和类黄酮的积累,保持了果实较高的抗氧化活性。     

臭氧处理对不同成熟度葡萄保鲜效果

为确定臭氧保鲜葡萄的最佳采摘期,以臭氧处理七、八、九成熟的3种不同成熟度的果实,测定其贮藏过程中相关理化指标的变化,包括可溶性糖含量、维生素C、可溶性固形物含量、可滴定酸、耐压力以及失重率和腐烂率等。结果表明:采用臭氧水处理葡萄时,八成熟果实在21d时的可溶性糖含量为13.84%,维生素C为5.18mg/100g,可溶性固形物含量为11.6%,可滴定酸为0.55%,耐压力为0.11MPa,失重率为0.75%,腐烂率为0.70%,贮藏保鲜效果最好,可为臭氧保鲜处理条件下的葡萄采摘时期提供技术参考。     

3种不同处理方法对冬枣贮藏品质的影响

以冬枣(Zizylphus vulgaris)为试材,研究了45℃热水浸果6 min、45℃2%CaCl2溶液浸果6 min、45℃2%CaCl2溶液浸果6 min后再经过2 kJ/m2短波紫外线照射3种预处理方式对冬枣在0℃贮藏期间,其抗氧化活性和PAL、MDA、细胞膜透性、硬度、转红指数和腐烂指数等与衰老相关生理生化指标的影响。结果表明:在0℃贮藏条件下,热水结合2%CaCl2的处理与CK和其他处理相比能更好地抑制MDA含量和细胞膜透性的增加,并延缓果实硬度的下降,有效抑制腐烂的发生。贮藏至75d,热水结合2%CaCl2处理的MDA含量和细胞膜透性与CK相比分别降低了30.2%和12.4%,且硬度比CK提高了32%。所有处理均可提高PAL的活性,但热水结合2%CaCl2处理后再经过2 kJ/m2紫外照射的冬枣,处理效果最好,在75 d时PAL的活性比CK提高了24.4%。热处理能够有效的减少冬枣的腐烂,以45℃2%CaCl2溶液处理最好,但热处理的冬枣果实转红指数明显高于CK。     

Control of Postharvest Quality in Blueberry Fruit by Combined 1-Methylcyclopropene (1-MCP) and UV-C Irradiation

The objective of this study was to investigate the effects of 1-methylcyclopropene (1-MCP) combined with UV-C irradiation on postharvest quality of blueberry fruit (Vaccinium spp. Berkeley) stored at 4 ± 1 °C for 8 days. Respiration rate, ethylene production, decay incidence, softness, color, total anthocyanin content, malondialdehyde (MDA) content, titratable acid content, soluble solid content, peroxidase (POD), phenylalanine ammonia lyase (PAL), and catalase (CAT) of treated blueberry fruit were examined. The results indicated that treatment with 1-MCP plus UV-C irradiation inhibited respiration rate, ethylene production, decay incidence, and MDA content. The combined treatment also delayed softness, color, titratable acid, and soluble solid content and improved total anthocyanin content of blueberries throughout the storage period at 4 ± 1 °C compared to the untreated samples. The efficiency of the combined treatment (1-MCP + UV-C irradiation) was better than that of 1-MCP or UV-C irradiation alone. Furthermore, combination of 1-MCP and UV-C irradiation effectively enhanced PAL and CAT activities and inhibited the increasing of POD activity in blueberries. Therefore, our results shows that 1-MCP plus UV-C irradiation treatments may be a useful method in maintaining commercial quality and extending shelf life of blueberries.