A combination of hot air treatment and nano‐packing reduces fruit decay and maintains quality in postharvest Chinese bayberries

BACKGOUND: Chinese bayberry is susceptible to microbial decay during postharvest handling and storage. To search for effective alternatives to currently used fungicides for disease control, the efficacy of hot air (HA) treatment at 48 °C for 3 h alone or in combination with nano‐packing (NP) containing nano‐TiO₂ and nano‐Ag in controlling green mould decay caused by Penicillium citrinum and natural decay, and their effects on fruit quality in harvested Chinese bayberries were investigated in this study. RESULTS: The combined treatment of HA and NP resulted in a remarkably improved control of green mould and natural decay in Chinese bayberries compared with treatment of HA or NP alone. The in vitro growth of P. citrinum was significantly inhibited by individual HA or NP. In addition, HA in combination with NP showed interactive effect on inhibiting fruit respiration, ethylene production and membrane lipid peroxidation, and maintained higher fruit firmness and DPPH radical scavenging activity. CONCLUSION: These results suggest that a combination of HA treatment and NP may be a useful technique to reduce fruit decay and maintain quality in Chinese bayberries during postharvest storage and retail conditions. Copyright © 2010 Society of Chemical Industry     

Effect of hot air treatment on quality and ripening of Chinese bayberry fruit

BACKGROUND: Postharvest decay and softening are the major factors limiting the extension of storage life of Chinese bayberry fruit. To evaluate the effects of hot air treatment (HAT) on Chinese bayberry fruit, fruits were stored at 2 °C after exposure to 20 °C (control), 40 °C (HAT₄₀), 45 °C (HAT₄₅) or 50 °C (HAT₅₀) hot air for 3 h. The effects of HAT on firmness, disease incidence, soluble solid content (SSC), titratable acidity (TA), respiration, ethylene production, pectic substances and activities of pectinmethylesterase (PME) and polygalacturonase (PG) were examined. RESULTS: HAT inhibited decrease in firmness, SSC and TA and retarded increase in disease incidence, while it promoted decrease in respiration rate and ethylene production. HAT suppressed the activities of PME and PG, which resulted in delaying the depolymerisation of chelator‐soluble and alkali‐soluble pectic substances and reducing the increase in water‐soluble pectic substances compared with control fruits. CONCLUSION: The present findings show that HAT can maintain postharvest quality and delay ripening of Chinese bayberry fruit and suggest that HAT could be considered for commercial use to extend the postharvest life of Chinese bayberry fruit. Copyright © 2008 Society of Chemical Industry     

超高压处理对杨梅鲜果感官品质的影响

为了探讨超高压处理对杨梅鲜果感官品质的影响,将杨梅("东魁"品种)鲜果在400～600MPa压力、室温条件下处理2min后,测定鲜果在25℃和4℃条件下储藏期间的感官品质变化,包括颜色、汁水流失、硬度、糖度、pH等指标的变化。结果表明:不同条件超高压处理后,样品的颜色、糖度、pH在储藏期间没有显著变化,汁水流失随着储藏时间的延长不断增大,鲜果硬度随着储藏时间增大而减小。不同超高压条件对杨梅鲜果的感官品质影响不显著。与未处理的鲜果品质变化速率对比,超高压处理后的鲜果品质变化速率显著减小,说明超高压处理可以有效延缓杨梅储藏期间的品质变化。     

糖代谢调控杨梅果实采后抗氧化活性机制研究进展

杨梅果实中天然抗氧化物质对人类健康的作用日益受到人们的重视, 抗氧化活性的大小已成为衡量果实采后品质的一个重要指标, 维持和提高果实采后抗氧化能力已成为果实采后贮运保鲜研究中的热点。糖代谢是果实采后主要的生理活动之一, 与果实采后花色苷和酚类物质的代谢存在密切的联系。本文简要介绍了杨梅果实的抗氧化特性, 重点综述了糖代谢调控果实采后抗氧化活性机制的研究进展, 提出了糖代谢调控杨梅果实采后花色苷和酚类物质合成代谢机制的研究展望。     

硼处理对杨梅果实采后贮藏期间蔗糖代谢及花色苷合成的影响

以"乌种"杨梅果实为试材,研究了硼(四硼酸钾)处理对采后杨梅果实在1℃贮藏期间品质、蔗糖代谢及花色苷合成的影响。结果显示:10 g/L为杨梅果实最大有效硼处理浓度,采用10 g/L硼处理可有效降低杨梅果实贮藏期间腐烂率并维持果实品质;10 g/L硼处理可显著抑制果实贮藏期间AI、SPS以及SS2(蔗糖合酶合成方向)活性的上升并提高SS1(蔗糖合酶分解方向)活性;同时,经硼处理的杨梅果实中葡萄糖和蔗糖含量明显低于对照果实,而果糖、总花色苷和矢车菊-3-葡萄糖苷含量却高于对照水平。由此推测,硼元素可通过直接调控杨梅果实采后贮藏期间蔗糖代谢酶活性来积累杨梅花色苷前体UDPG,从而为杨梅果实花色苷的合成提供底物,最终起到促进果实花色苷合成和改善贮藏品质的作用。     

Effects of Vacuum Impregnation with Calcium Ascorbate and Disodium Stannous Citrate on Chinese Red Bayberry

This study aimed to improve the shelf life of Chinese red bayberries using vacuum impregnation. Vacuum pressure of 5 kPa for 15 min, atmospheric pressure for 10 min, an impregnation temperature of 20 °C, alone or in combination with isotonic sucrose solution, 1% food-grade disodium stannous citrate (DSC) and 2% food-grade calcium ascorbate were used for vacuum impregnation. Quality parameters, including firmness, weight loss, decay rate, microbial counts and polyphenol oxidase (PPO) and peroxidase (POD) activities, of red bayberries were studied at 2 °C for 10 days. The monosaccharide components, chemical structures and nanostructure properties of chelate-soluble pectin (CSP) were further studied using high-performance liquid chromatography, Fourier transform infrared spectroscopy and atomic force microscopy (AFM). The results indicated that vacuum impregnation with calcium ascorbate alone or calcium ascorbate combined with DSC showed significant effects on inhibiting the decrease of firmness (4–10 days), the increase of weight loss (2–10 days), decay rate (4–10 days) and microbial growth (2–10 days). In addition, vacuum impregnation with single calcium ascorbate or DSC or their combination significantly inhibited the increase of colour difference from day 6 to day 10 during storage, which was better than atmospheric impregnation. Furthermore, vacuum impregnation with DSC and calcium ascorbate had the best effect on sensory attributes. The nanostructure analysis by AFM showed CSP of large width and length when calcium ascorbate was impregnated, suggesting that vacuum impregnated with 2% calcium ascorbate inhibited the degradation and dissociation of CSP, although these fruits showed more branching of rhamnogalacturonan and a small change in chemical structure.     

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     

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。     

姜油树脂对采后橄榄果实抑菌效果和贮藏品质的影响

小孢拟盘多毛孢（Pestalotiopsis microspora）是引起橄榄果实腐烂的最主要病原菌之一。为给姜油树脂在采后橄榄果实贮藏保鲜应用提供科学依据和实践指导,本实验研究了姜油树脂对采后橄榄果实的抑菌效果和贮藏品质的影响。以‘长营’橄榄果实为材料,通过损伤接种法,研究不同剂量的姜油树脂对P. microspora接种橄榄果实的抑菌效果,并进一步探讨最佳抑菌剂量的姜油树脂对采后橄榄果实在25 ℃下贮藏49 d期间果实病害发生和品质的影响。结果表明：与对照比较,姜油树脂可显著抑制P. microspora侵染所致橄榄果实采后病害发生,其中姜油树脂的最佳抑菌剂量为30 μL/mL;30 μL/mL的姜油树脂处理可显著降低橄榄果实病害指数和果皮褐变指数（P＜0.01）,延缓橄榄果实可溶性固形物、可溶性总糖、可滴定酸、VC、总酚及类黄酮含量的下降,较好保持采后橄榄果实的外观颜色和营养品质。因此认为,30 μL/mL的姜油树脂处理可有效控制橄榄果实采后病害发生,保持橄榄果实贮藏品质。     

Postharvest Quality of Strawberry Fruit (<Emphasis Type="Italic">Fragaria x Ananassa</Emphasis> Duch cv. Albion) as Affected by Ozone Washing: Fungal Spoilage,Mechanical Properties,and Structure

Storage life of strawberry fruit is limited due to its high softening rate and susceptibility to fungal attack. Thus, it is of interest to develop and improve preservation techniques to reduce postharvest losses. The aim of this study was to evaluate the effect of ozonized water washing (maximum concentration of 3.5 mg L^?1; 5–15 min) on fungal spoilage, water loss, mechanical properties, and structure of strawberries (cv. Albion) harvested in different years and stored at 5 °C. The effect of ozone treatment on decontamination and weight loss was dose-dependent. Ozonization for 5 min significantly reduced fungal incidence (~?22–25% lesser than control) and weight loss of strawberries throughout storage. High doses (10 or 15 min) did not reduce significantly fungal growth in relation to control, although weight loss in fruit treated for 15 min was higher than control. In both harvest years studied, cold storage provoked a diminution in deformability modulus and an increase in deformation but a significant effect of treatment was not observed. These changes were correlated with alteration of cell walls and turgor loss. Otherwise, cuticular membrane of strawberries treated for 5 min was observed thicker and more electron dense than in fruit ozonized for 15 min or control. It could partially explain the lower moisture loss observed in 5-min treated fruit. Results showed that ozonized water washing for 5 min can be an alternative strategy for extending postharvest strawberry shelf-life by decreasing fungal decay and water loss along cold storage, without affecting mechanical parameters.     

减压和1-MCP处理对杨梅保鲜效果的影响

为探究减压保鲜的机理及1-甲基环丙烯（1-MCP）在减压保鲜上的应用,以宜兴杨梅为实验材料,常压冷藏处理为对照,研究1.5 kPa （3±1） ℃减压处理20 d、减压预处理12 h和减压预处理12 h结合1-MCP常压冷藏至20 d各处理组生理指标的变化情况。结果表明,减压处理20 d对降低杨梅腐烂率的效果最为显著,其次为减压预处理和减压预处理结合1-MCP组,且都优于常压冷藏对照组（P＜0.05）。减压预处理和减压处理均可降低杨梅呼吸强度,维持超氧化物歧化酶（SOD）、过氧化物酶（POD）活性和增加苯丙氨酸解氨酶（DAL）的活性,多酚氧化酶（PPO）活性受影响程度较小,且减压处理和减压预处理均可抑制杨梅表面微生物的生长。结合1-MCP处理可以进一步抑制呼吸强度和保持相关酶的活性,降低杨梅的腐烂情况。     

Assessment of coating tomato fruit with shrimp shell chitosan and N,O-carboxymethyl chitosan on postharvest preservation

The effect of coating tomato fruit (Lycopersicon esculentum) with shrimp shell chitosan, a deacetylated form of chitin, and a chitosan derivative, i.e. N,O-carboxymethyl chitosan (NOCC) on postharvest preservation was studied. The effects of various chitosan and NOCC concentrations on fruit ripening behavior, as well as fruit physical and chemical characteristics were evaluated during storage at room temperature (25–30 °C). Coating the fruit with 2 % (w/v) chitosan or NOCC solutions was found to be more effective in extended its storage life than coating with 0.5 % (w/v) solutions. Covered tomatoes were firmer, higher in titratable acidity, and exhibited less red pigmentation than the control uncoated fruits at the end of storage. These results suggest the suitability of chitosan and its derivative NOCC as an alternative means of preserving fresh fruits.     

Effect of hexanal vapour on longan fruit decay,quality and phenolic metabolism during cold storage

The effects of postharvest treatment with hexanal vapour on longan fruit decay, quality, hexanal residue, phenolic compound content, and polyphenoloxidase (PPO) and peroxidase (POD) activities were studied during storage at 5 °C for 30 days. Hexanal exposure for 2 h at 900 μL L^?1 before cold storage reduced the percentage of fruit with decay and was deemed the optimum treatment. Hexanal exposure resulted in a pericarp that was more reddish brown and less intense in colour. Hexanal residue in the pericarp and aril of fumigated fruit was several fold higher than that of nonfumigated fruit, although levels were low at the end of cold storage. Electrolyte leakage of pericarp increased during 5 °C storage and was further increased by hexanal exposure. Hexanal reduced pericarp phenolic content, and increased PPO and POD activities. Overall, use of hexanal vapour reduced postharvest disease of longan fruit but increased the likelihood of pericarp browning.     

Influence of nano-ZnO on microbial growth,bioactive content and postharvest quality of strawberries during storage

A rapid decline of quality causes economic loss of strawberries after harvest. Treatments based on nano-ZnO at different concentrations (0.03%, 0.07% and 0.5%) were used to prolong the shelf-life of strawberry fruit in cold storage. After treatments microbial growth, weight loss, firmness, titratable acidity, soluble solid content, pH value, vitamin C, anthocyanin and total phenolics and antioxidant activity were evaluated at 0, 3, 6, 9, 12, 15 and 18 days of storage. Furthermore, the levels of zinc and the sensory attributes of treated strawberries were evaluated three days after treatment. Nano-ZnO treatments decreased the microbial load during fruit storage (total mesophilic bacteria in control and 0.5% nano-ZnO treated strawberries were 4.35 and 3.67 Log CFU g^− 1, respectively). Treatments delayed weight loss, retained fruit firmness and maintained anthocyanin, vitamin C, phenol content and antioxidant activity at higher concentration than those of untreated fruit. Fruit sweetness and aftertaste attributes were not affected by treatments but the 0.5% ZnO treated fruit was less luminous (1.6) compared to control (5.6). 0.5% nano-ZnO was the most effective in delaying changes in the ripening and reducing microbial populations among the treatments. These findings indicated that the nano-ZnO might provide an alternative to maintain quality and control decay of fresh strawberries during extended storage.Industrial relevanceStrawberries are a highly perishable fruit and postharvest life is limited to 4 days or even shorter at room temperature or 2 weeks at cold storage, therefore finding a method to extend the shelf life of strawberries is important. Modified atmosphere packaging is a useful method but control of spoilage microorganisms is still a problem. Fruit coating has great potential to extend fruit postharvest life and maintain nutritional quality. Nano-ZnO may be an effective alternative.     

杨梅果实采后热空气处理条件的优化

采用响应曲面法研究了不同温度-时间组合的热空气处理对"乌种"杨梅果实采后贮藏品质的影响,并对热空气条件进行了优化。结果表明:当热处理温度为48.5℃,处理时间为173 min时,有最优贮藏保鲜效果:杨梅果实于1℃下贮藏7 d再转移至20℃下模拟货架期放置1 d后的腐烂指数为18.81%、硬度为3.31 N、Vc含量为5.25 mg/kg(鲜重)、固酸比为16.42。     

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.     

Effects of short‐term N2 treatment on quality and antioxidant ability of loquat fruit during cold storage

BACKGROUND: Loquat fruit is susceptible to microbial decay and quality deterioration during postharvest distribution. In this study, in a search for effective alternatives to methods currently used for quality maintenance, the effects of short‐term pre‐storage N₂ treatment on the quality and antioxidant ability of loquat fruit were investigated. RESULTS: Loquat fruits were exposed to 100% N₂ for 6 h at 20 °C and then stored at 5 °C for 35 days. Short‐term N₂ treatment significantly delayed the increase in fruit decay rate and decreases in total soluble solid and titratable acidity contents, thereby maintaining better eating quality and extending the storage life of fruits. It also markedly delayed increases in membrane permeability, malondialdehyde content and superoxide anion production rate. In addition, N₂‐treated fruits exhibited significantly higher superoxide dismutase and catalase activities and lower lipoxygenase activity than control fruits. CONCLUSION: Short‐term pre‐storage N₂ treatment effectively reduced fruit decay and maintained quality in loquat fruits during cold storage. The reduction in fruit decay and quality deterioration by the treatment was correlated with enhanced antioxidant ability and reduced lipid peroxidation. Copyright © 2009 Society of Chemical Industry     

Effect of exogenous fludioxonil postharvest treatment on physiological response,physico-chemical,textural, phytochemical and sensory characteristics of pomegranate fruit

The study investigated the effects of fludioxonil (FLU) on the postharvest quality of pomegranate fruit (cv. Wonderful). Fruits were dipped in FLU concentrations (control, 150, 300 and 600 mg/L) and stored for 4 months at 5?°C and 90–95% relative humidity (RH) plus an additional 4 days at 20?°C and 65% RH. Effects of FLU were evaluated on physiological responses, quality and sensory attributes. Results showed that fruit weight loss and decay incidence were reduced by FLU treatment, with fruit treated with 600 mg/L concentration showing the best results. Fruit respiration rate was more influenced by storage duration than FLU concentration. The severity and occurrence of physiological disorders increased with storage duration but were more pronounced in fruits treated with FLU. Storage duration influenced fruit colour whereas aril colour was affected by FLU concentration. Untreated fruit showed better aril redness and chroma although treated fruit also had acceptable red colour. Chemical quality attributes of fruit juice were not significantly affected by FLU concentrations. Fruit treated with FLU had significantly (p?<?0.05) higher total phenolic content during storage although lower ascorbic acid content was observed compared to untreated fruit. Treating fruit with FLU resulted in better sensory attributes with regards to crispness, juiciness and sweetness. Overall, this study showed that fruit treated with FLU at 600 mg/L had the best quality with respect to decay incidence, weight loss, total phenolics and sensory attributes.     

杨梅玻璃态保藏技术的研究

以杨梅(东魁)果实为研究对象,测定其玻璃化转变温度(Tg),并将该温度应用于实际的冻结保藏中。研究发现,杨梅部分玻璃化转变温度(Tg')的起始点为－ 44℃,中点为－ 42℃,终止点为－ 39.2℃。与－ 18℃冻藏相比较,－ 40℃冻结保藏(模拟玻璃态保藏)的果实解冻后汁液流失率低,可溶性固形物(SSC)含量高,果汁pH 值和可滴定酸(TA)含量无显著差异;仪器分析和感官评定的结果均表明,－ 40℃冻结保藏更有利于保持杨梅果实的质地品质。     

Effect of sucrose‐based polymers on quality of Satsuma mandarin fruit (Citrus unshiu Marc. cv. Miyagawa Wase)

In this study, the effects of an edible coating (sucrose‐based polymers, SBP) on postharvest fruit quality of Satsuma mandarin (Citrus unshiu Marc. cv. Miyagawa Wase) were investigated. All the fruit except the control was sprayed with SBP solution at a concentration of 0.1%, 0.3%, 0.5% and 1.0% (v/v), respectively, and then stored at room temperature (25 °C, 85% relative humidity) for 25 days. Results showed that 0.1%, 0.3% and 0.5% SBP treatment could significantly increase the soluble solids concentrations (SSC), vitamin C (Vc), total sugars, total carotenoids, the ratio of SSC to titratable acidity (TA) (SSC/TA), catalase (CAT), peroxidase (POD) and superoxidase dismutase (SOD) activities, while the decay rate, TA and polyphenol oxidase (PPO) activity were greatly reduced. In contrast, 1.0% SBP treatment resulted in fruit browning, despite maintaining fruit quality. Our present study provided the theoretical data for the practical application of the SBP on the citrus fruit quality of during postharvest storage.