Total Antioxidative Capacity and Total Phenolic Levels in Pomegranate Husks Correlate to Several Postharvest Fruit Quality Parameters

The demand to extend the marketing period of pomegranates requires a better understanding of the processes occurring during postharvest storage. Among the important factors that limit the long-term storage of pomegranates are disorders occurring on the fruit husk: fungal decay, chilling injury, shrinkage due to weight loss, and husk scald, all leading to loss of visual quality. The aim of this study was to examine processes that taking place during storage, and to analyze the relationship between the total antioxidant capacity and total phenolics content of the husks and the development of husk disorders in seven accessions. While the level of total phenolics increased during storage, concomitantly with the color index, the level of punicalagin, the main polyphenol in the husks with the highest antioxidant activity, declined during storage. The content of titratable acidity was also reduced. Regression analysis indicates that fruit having a high antioxidant capacity, high total phenolics content, and high levels of punicalin in their husks have a better ability to resist fungal decay and weight loss, in addition to being less sensitive to husk scald. On the other hand, the results suggest that the development of most husk disorders is not correlated to the content of total soluble solids, titratable acidity, punicalagin, anthocyanin, or husk color. Nonetheless, poorly colored accessions were relatively more sensitive to chilling injury expressed as surface pitting, compared with the more colored accessions. The appearance of these chilling injury symptoms was not correlated to total phenolics or the antioxidant capacity.     

Vapour treatments with methyl salicylate or methyl jasmonate alleviated chilling injury and enhanced antioxidant potential during postharvest storage of pomegranates

Pomegranates were treated after harvest with methyl jasmonate (MeJa) or methyl salicylate (MeSa) at two concentrations (0.01 and 0.1 mM), and then stored under chilling temperature for 84 days. Control fruits exhibited chilling injury (CI) symptoms manifested by pitting and browning, the severity being enhanced as storage time advanced, and accompanied by softening and electrolyte leakage (EL). The CI symptoms were significantly reduced by MeJa or MeSa treatments, without significant differences among treatments or applied dose. In addition, both treatments significantly increased total phenolics and anthocyanins with respect to controls. Hydrophilic (H-TAA) and lipophilic (L-TAA) total antioxidant activity decreased in control arils, but in both MeJa and MeSa treated fruits H-TAA increased while no significant changes occurred for L-TAA. Results would suggest that both MeJa and MeSa have potential postharvest applications in reducing CI, maintaining quality and improving the health benefits of pomegranate fruit consumption by increasing the antioxidant capacity.     

水杨酸用于水果采后贮藏保鲜的研究进展

综述近年来使用水杨酸减少水果腐烂、延缓采后果实成熟衰老、保持果实品质、增强果实抗冷害性能和诱导采后果实对病原菌的抗性等方面的研究进展,并展望水杨酸用于水果采后贮藏保鲜的趋势和研究方向.     

冷害对茄子果实贮藏品质的影响

研究冷害对茄子果实贮藏品质的影响,旨在阐明冷害温度下茄子果实品质劣变的规律。茄子采后分别于冷害温度[(40 ± 1)℃,简称4℃]和非冷害温度[(13 ± 1)℃,简称13℃]贮藏10d,定期测定贮藏期间两组的品质变化。结果显示,4℃条件下茄子果实在第4 天表面出现轻微褐变,随后日趋严重,而在13℃条件下的果实10d 内未发生冷害症状。冷害会加速茄子采后失重率和膜透性的上升,促进叶绿素、可滴定酸(TA)和VC 含量下降,促进贮藏中、后期(4～10d)可溶性糖、还原糖、可溶性蛋白和游离氨基酸含量下降。可见,冷害会促进茄子采后贮藏品质的劣变,降低茄子的食用价值和商品价值。     

Postharvest physiology and technology of loquat (Eriobotrya japonica Lindl.) fruit

Loquat (Eriobotrya japonica Lindl.) is a subtropical evergreen tree whose fruit is consumed both fresh and processed. Loquat fruit is a good source of minerals and carotenoids, while the kernel is rich in protein and carbohydrates. It has been considered a non‐climacteric fruit, but there is evidence that some cultivars have a ripening pattern similar to that of climacteric fruits. The fruit has a short postharvest life at ambient temperatures and is susceptible to physical and mechanical damage, loss of moisture and nutrients, and decay. Low‐temperature storage extends the shelf life of loquat fruit, but some cultivars are severely affected by chilling injury and flesh browning during cold storage. Purple spot, browning and leatheriness are major postharvest disorders. The shelf life of loquat can be extended by modified or controlled atmosphere storage as well as by postharvest treatment with 1‐methyl cyclopropene or methyl jasmonate. © 2014 Society of Chemical Industry     

Maintaining mango (Mangifera indica L.) fruit quality during the export chain

Mangoes are tropical/sub tropical fruit with a highly significant economic importance. Preferable quality attributes include freedom from external damages such as bruises, latex or sap injury and decay, uniform weight, colour, aroma, firmness (with little give away, not soft), shape and size. The fruit is rich in antioxidants and recommended to be included in the daily diet due to its health benefits such as reduced risk of cardiac disease, anti cancer, and anti viral activities. Maintenance of mango fruit quality during the supply chain depends on many aspects including adequate orchard management practices, harvesting practices, packing operation, postharvest treatments, temperature management, transportation and storage conditions, and ripening at destination. Postharvest losses are high during the supply chain due to harvesting fruit at improper maturity, mechanical damage during the whole chain, sap burn, spongy tissue, lenticels discolouration, fruit softening, decay, chilling injury, and disease and pest damage. The aim of postharvest treatments and management practices in the supply chain is to create suitable conditions or environments to extend the storage life and retain the quality attributes, nutritional and functional compositions. This review summarises the available research findings to retain the overall mango fruit quality and to reduce postharvest losses during supply chain by adopting suitable postharvest novel technologies.     

1-MCP对净皮甜石榴的冷藏保鲜效果

对陕西临潼净皮甜石榴采后用不同浓度(0.25、0.5、1.0、1.5μL/L)1-MCP处理后于4℃冷藏,定期测定了部分采后生理指标并统计果实的腐烂情况。结果表明,1-MCP处理能维持果实相对较高水平的有机酸含量、出汁率和花青苷含量,抑制了石榴果皮相对电导率的上升速率,降低了石榴的乙烯释放速率,从而延缓果实的衰老,有效降低了冷藏期和货架期石榴的腐烂率与腐烂指数。在0.25～1.5μL/L的1-MCP浓度范围内,处理浓度越低,果实品质和保鲜效果越好。     

桃果实冷害发生机理及御冷措施研究进展

桃果实因其呼吸跃变的特点,采后在室温下会出现呼吸高峰与乙烯释放高峰,极易腐烂,不耐贮藏。冷藏是延长桃果实贮藏期的最有效方法之一,但由于桃果实的冷敏性,长期的不适低温易使桃产生冷害,引起果肉革质化、组织絮败、褐变、固有风味损失等品质劣变问题,成为桃产业健康发展的重要影响因素。本文综述了目前桃果实采后冷害发生的机理的研究进展,总结了冷害对桃果实细胞膜、细胞壁代谢、抗氧化系统及精氨酸代谢的影响,并针对相关机制归纳了桃果实采后冷害控制技术,旨在为桃果实采后保鲜研究和应用提供理论与技术依据。     

Postharvest physiology and technology of Annona fruits

Annona comprises many species but 5 of them are of significant commercial importance, namely the custard apple, cherimoya, soursop, bullock's heart and atemoya. The postharvest system for these fruits is not yet adequately developed, and therefore several handling problems are still common. Rapid softening of fruits after harvest, especially during transportation and marketing is a major ongoing problem. Annonas are climacteric fruit, generally characterized by high respiration and ethylene production, and are chilling sensitive. Extended fruit storage periods are still not possible, mainly because of the high susceptibility to chilling injury. Although still limited, there has been some postharvest research on these fruits in the last 2-3 decades, but scattered in diverse sources, especially local and regional sources and in several languages, and therefore this review attempts to outline some of the important findings, especially on maturity and harvesting indices, respiration, ethylene production, ripening changes, different treatments to extend the storage and shelf life of the fruit.     

间歇升温对采后香蕉李贮藏中酶促褐变的影响

以香蕉李为试材,研究不同的间歇升温对低温贮藏的李果实酶促褐变的影响。结果表明,李果实在冷藏20d 时启动冷害,多酚含量和PPO 活性逐渐下降,冷害指数显著增大,果实正常后熟过程受阻。同时,低温胁迫诱导了SOD 活性的增加,而冷害又激发CAT 或POD 活性的上升,说明受冷害果实的保护酶系统在抵抗逆境胁迫方面具有一定的协同作用。随着贮藏时间的延长,MDA 含量逐渐上升,冷害和褐变程度加剧。而间歇升温提高了SOD、POD 和CAT 的活性,抑制了活性氧的积累,减弱了膜脂过氧化的程度,延缓了冷害的发生,特别是间歇升温到18℃抑制冷害的效果更好,促进果实逐渐后熟,延迟了果实的衰老进程。而间歇升温到10℃贮藏前期虽然对冷害症状有所缓解,但果实成熟老化速度较快,贮藏后期老化的果实不耐低温贮藏,导致冷害加剧,果实褐变现象严重。     

外源钙和钙调素拮抗剂对冷藏桃果实耐冷性的影响

以‘白凤’水蜜桃为试材,分别用外源钙（CaCl2）和钙调素拮抗剂三氟拉嗪（trifluoperazin,TFP）浸泡桃果实,以蒸馏水为对照,研究其对冷藏桃果实抗冷性的影响。结果表明：与对照组相比,CaCl2处理能有效减轻桃果实果心褐变程度,缓解冷害症状,降低相对电导率,降低丙二醛（malondialdehyde,MDA）、H2O2含量,降低超氧阴离子自由基（O2 － ·）产生速率以及脯氨酸脱氢酶（proline dehydrogenase,PDH）活力,提高活性氧代谢相关酶（超氧化物歧化酶（superoxide dismutase,SOD)、过氧化氢酶（catalase,CAT）、抗坏血酸过氧化物酶（ascorbate peroxidase,APX）、Δ1-吡咯啉-5-羧酸合成酶（Δ1-pyrroline-5-carboxylate synthetase,P5CS）、鸟氨酸氨基转移酶（ornithine δ-aminotransferase peroxidase,OAT）、谷胱甘肽还原酶（glutathione reductase,GR））活力;另外,CaCl2处理后的桃果实表现为较高的脯氨酸、VC和谷胱甘肽（glutathione,GSH）含量;而TFP处理后的桃果实冷藏特性与CaCl2处理组相反。这说明钙-钙调素（Ca2＋-CaM）复合体参与了采后桃果实抗冷性调控,Ca2＋浓度的增加能维持桃果实活性氧代谢平衡,减少低温胁迫下膜脂过氧化与损伤,增加渗透调节物质脯氨酸的积累,从而减少桃果实冷藏期间冷害的发生,保持果实营养品质,延长果实贮藏时间。     

石榴贮藏期间间歇升温处理对果实品质的影响

以陕西临潼净皮甜石榴为试材,研究了间歇升温处理对石榴果实贮藏期间品质变化的影响。结果表明:石榴在(5.0±0.5)℃条件下贮藏,每隔6 d在(15±0.5)℃下间歇升温处理24 h,能有效保持果粒可溶性固形物含量、总糖含量和可滴定酸含量,减缓果皮褐变指数升高速率,降低果实腐烂率,贮藏120 d果实外观色泽鲜艳.籽粒感官品质良好,保鲜效果理想。     

CPPU处理对‘华优’猕猴桃品质及耐贮性的影响

以‘华优’猕猴桃为试材,于盛花后15 d分别用10、20 mg/L氯吡苯脲(1-(2-chloropyridin-4-yl)-3-phenylurea,CPPU)浸蘸猕猴桃幼果,清水作为对照,研究不同质量浓度CPPU处理对采后‘华优’果实的品质和耐贮性影响。结果表明:CPPU处理能有效增大果实单果质量,且增幅与CPPU使用质量浓度呈正比,但CPPU处理不同程度降低了果实外观品质(果形指数)和风味营养品质含量(干物质含量、可溶性总糖含量、糖酸比、VC含量),20 mg/L处理时负面影响最为严重。CPPU处理降低了果实耐贮性,贮藏过程中,20 mg/L处理其呼吸速率、乙烯释放速率、膜损伤程度高于其他处理,果实冷敏性提高,冷害率、冷害指数显著高于对照,贮藏90 d后果实质量损失率高,好果率低。10 mg/L处理对果实品质、耐贮性损害显著小于20 mg/L但大于对照。     

臭氧处理对新疆厚皮甜瓜贮藏品质和生理特性的影响

研究4 种不同贮藏条件（－1～0 ℃条件下5×10－6 m3/m3（以空气计）臭氧处理和5～6 ℃条件下2×10－6、4×10－6 m3/m3臭氧及2%～5% O2结合2%～4% CO2处理）对新疆厚皮甜瓜贮藏品质和生理特性的影响,贮藏过程中每15 d测定呼吸强度、乙烯释放速率、可溶性固形物含量、可滴定酸含量、pH值、果肉硬度、还原糖含量和过氧化物酶（POD）活性;贮藏68 d统计所有处理组甜瓜的腐烂和冷害情况。结果表明：低温冷藏（－1～0 ℃）条件下的甜瓜呼吸强度最低,但是出现了冷害现象,68 d时冷害指数为39%;贮藏于5～6 ℃条件下每日通入30 min2×10－6 m3/m3臭氧气体的甜瓜贮藏效果好于对照组,贮藏于5～6 ℃条件下每日通入30 min 4×10－6 m3/m3臭氧气体的甜瓜贮藏效果最好,其中呼吸高峰延迟出现,且呼吸强度降低,同时乙烯释放速率最小,还原糖含量、果肉硬度和POD活性较高,68 d时的腐烂指数仅为0.318;5～6 ℃环境下的气调（2%～5% O2）甜瓜可滴定酸含量最高,与其他处理组的差异性极显著（P＜0.01）;对照果实贮藏效果最差。     

Alleviation of chilling injury in postharvest tomato fruit by preconditioning with ultraviolet irradiation

BACKGROUND: Tomato fruit is usually stored at low temperatures for delayed ripening and extended shelf life. However, tomato fruit is susceptible to chilling injury when exposed to low temperatures. In this study, the potential effects of preconditioning with UV‐C or UV‐B irradiation on chilling injury of postharvest tomato fruit were investigated. RESULTS: Mature–green tomato fruit were exposed to 4 kJ m^?2 UV‐C or 20 kJ m^?2 UV‐B irradiation and stored for 20 days at 2 °C and subsequently 10 days at 20 °C. UV irradiation was effective in reducing chilling injury index and delaying ethylene peak. Furthermore, UV irradiation preserved storage quality as manifested by reduced weight loss, better retention of firmness, and higher contents of total soluble solids, soluble protein and soluble sugar during subsequent storage at 20 °C. UV‐C irradiation significantly delayed the development of the red colour after 10 days of storage at 20 °C. On the other hand, UV irradiation decreased total phenolics content and antioxidant capacity, suggesting possibly reduced stress response to low temperature resulted from enhanced physiological adaptation by UV preconditioning. CONCLUSION: Our results suggest that preconditioning with UV‐C or UV‐B irradiation in appropriate doses had a positive effect on alleviating chilling injury in postharvest tomato fruit. Copyright © 2012 Society of Chemical Industry     

Modified atmosphere packaging confers additional chilling tolerance on ethylene-inhibited cantaloupe Charentais melon fruit

Cantaloupe Charentais melon fruits are subject to chilling injury when stored at low temperatures, around 2 °C. Ethylene-suppressed cantaloupe Charentais melon, expressing a 1-aminocyclopropane-1-carboxylic acid (ACC)-oxidase gene in antisense orientation, showed strong, but not total, resistance to chilling injury, allowing an extended storage at low temperatures. Modified atmosphere packaging (MAP) is known to alleviate chilling injury symptoms in a variety of chilling-sensitive horticultural commodities. In the present work, we have compared the effects of MAP in non-retractile plastic film and storage in air on ethylene production, respiratory activity, development of chilling injury symptoms, water loss, ion leakage and accumulation of ethanol and acetaldehyde in wild-type and ethylene-suppressed melons, during storage at 2 °C and after re-warming at 22 °C. MAP reduced chilling injury and extended the postharvest life of wild-type fruit and conferred additional chilling resistance on ethylene-suppressed melons. Reduction of ethylene production and water loss are necessary to prevent chilling injury symptoms in melon.     

低温结合1-MCP处理对突尼斯软籽石榴采后品质的影响

突尼斯软籽石榴在贮藏过程中容易出现果皮褐变、籽粒变质、软化腐烂等问题,严重影响果实的商品价值。以陕西潼关突尼斯软籽石榴为试材,研究低温结合1-甲基环丙烯(1-methyl-cyclopropene,1-MCP)处理对采后突尼斯软籽石榴品质的影响,即在贮藏温度(3±0.5)℃、相对湿度90%~95%条件下,选用0.2、0.5、1.0、1.5 mg/L四种不同质量浓度的1-MCP处理软籽石榴,贮藏期间每20 d测定石榴果实的可滴定酸、可溶性固形物、还原糖含量,呼吸强度、相对电导率、褐变指数及多酚氧化酶、过氧化物酶活性,并计算果实失重率和腐烂率,贮藏120 d时对软籽石榴的感官性状进行综合评价。结果表明,采用1.0 mg/L的1-MCP处理软籽石榴能有效减缓果实腐烂变质,减缓果实呼吸强度,降低褐变指数,较好地保持籽粒可溶性固形物、可滴定酸及还原糖含量,并使多酚氧化酶、过氧化物酶活性处于较低水平,降低果实失重率和腐烂率,保持良好的感官品质。突尼斯软籽石榴适宜的贮藏条件为:贮藏温度(3±0.5)℃、相对湿度90%~95%、1-MCP处理质量浓度1.0 mg/L,并用聚乙烯塑料袋密封包装,保鲜效果理想。     

不同方式贮藏对拉萨刺梨品质的影响

本研究以拉萨地区刺梨果实为试材,分别采用室温、室温＋气调袋、低温（（1.0±0.5）℃）和低温 （（1.0±0.5）℃）＋气调袋4 种方式贮藏,测定贮藏过程中硬度、可溶性固形物质量分数、可滴定酸质量分数、 VC含量、超氧化物歧化酶（superoxide dismutase,SOD）活力、质量损失率、腐烂率的变化,研究不同方式贮藏对 刺梨品质的影响。结果表明：在贮藏6 d时,室温、室温＋气调袋、低温和低温＋气调袋贮藏的刺梨VC含量分别下 降了69.55%、25.91%、41.93%和14.47%,SOD活力分别下降了47.99%、24.96%、33.98%和14.32%,在贮藏6 d时仅 室温＋气调袋处理的刺梨有腐烂现象出现,腐烂率为1.78%;与其他贮藏方式相比,低温＋气调袋贮藏组果实的硬 度、可溶性固形物质量分数、可滴定酸质量分数、质量损失率等下降明显变缓,贮藏综合品质最好。     

石榴适温气调保鲜技术研究

以陕西临潼净皮甜石榴为试验材料,研究了不同温度和气体成分条件下石榴贮期生理变化特性,通过对其外观色泽和内部籽粒品质比较,获得了理想的适温气调保鲜技术参数:贮藏温度4～5℃,相对湿度90%～95%,气体成分O2=3%、CO2=3%,在此条件下贮藏石榴100d,可溶性固形物含量14.2%,总酸含量0.384%,果皮褐变指数0.12,果实腐烂率3.5%,贮后果实色泽鲜艳,籽粒晶莹剔透,风味酸甜适口。     

河阴石榴的采后保鲜技术

研究贮藏温度、化学杀菌剂处理和涂膜对河阴石榴果皮褐变、质量损失率、腐烂及籽粒品质等指标的影响。结果表明,在120 d的贮藏期内,4.5 ℃会引起河阴石榴果实冷害,果皮褐变严重、腐烂率增大。1%壳聚糖涂膜处理降低果实的腐烂率、褐变指数和质量损失率的效果优于1%海藻酸钠和1%羧甲基纤维素钠涂膜。噻菌灵、甲基托布津和多菌灵1 000 倍稀释液浸果60 s可以显著降低果实腐烂率,3 种化学杀菌剂处理之间无显著差异。以42%噻菌灵悬浮剂1 000 倍液浸果,而后以1%壳聚糖溶液涂膜,用0.015 mm聚乙烯保鲜袋单果包装后放入6 ℃条件下贮藏120 d,河阴石榴的腐烂率为3.46%,质量损失率为2.13%,褐变指数为0.11,可溶性固形物含量为14.5%,籽粒品质评分为92,具有较高的商品价值。