The Effects of Harvest Maturity on Storage Quality and Sucrose-Metabolizing Enzymes During Banana Ripening

Mature green “Baxi” banana (Musa spp. AAA Group, Cavendish) fruits were harvested at 60% and 80% maturity stages. In order to evaluate the effects of harvesting at different maturity stages on storage quality and changes in sucrose-metabolizing enzymes, fruit firmness, disease index, contents of starch, and total soluble sugars were determined, and enzyme activities associated with sucrose metabolism was investigated under natural and accelerated (treated with ethylene) ripening conditions. In fruit treated with ethylene, changes in flesh firmness, total sugar content, starch content, disease index, and activity of sucrose phosphate synthase (SPS), sucrose synthase (SS), acid invertase (AI), and neutral invertase (NI) were accelerated dramatically compared with untreated fruit with both 60% and 80% maturity. When fruit ripened under natural conditions, the changes in firmness, disease index, starch content, total sugar content, SPS activity, SS, AI, and NI activity in fruit with 80% maturity were significantly faster than those in fruit with 60% maturity. On the contrary, when fruit ripened under accelerated conditions, no significant differences in firmness, sugar, starch, disease index, SPS, SS, AI, and NI were observed between fruit harvested at 60% or 80% maturity. It is suggested that storage quality and sucrose-metabolizing enzymes of banana fruit stored under natural conditions are related to harvest maturity stage; storage quality of fruit with lower harvest maturity is better than fruit with higher maturity. However, when fruit ripening is accelerated by ethylene, the harvest maturity stage has no influence on storage quality and changes in sucrose-metabolizing enzymes.     

Compositional changes during guava fruit ripening

Compositional changes of fruit pulp and peel during ripening of white- and pink-fleshed guava fruits were studied. The white and pink guava fruits exhibited a typical climacteric pattern of respiration. Fruit tissue firmness decreased progressively, in a similar manner, in both guava fruit types. Total soluble solids (TSS) and total sugars increased in pulp and peel of both guava types with decrease in flesh firmness. More increase in total sugars was observed after the climacteric peak of respiration. Reducing sugars and titratable acidity increased up to the full-ripe stage and then decreased. Ascorbic acid and phenolic compounds decreased continuously during ripening of the two types. The peel showed higher values of ascorbic acid, total protein and phenolic compounds than the plup. The white-fleshed guavas had higher levels of TSS, total sugars, reducing sugars. titratable acidity, phenolic compounds and ascorbic acid content then the pink-fleshed fruits.     

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。     

Effect of preharvest sprays containing calcium,magnesium and titanium on the quality of peaches and nectarines at harvest and during postharvest storage

Peach and nectarine trees were foliar sprayed with a formulation containing Ca²⁺, Mg²⁺ and Ti⁴⁺. Parameters related to fruit quality were evaluated at harvest, after 7–28 days of cold storage and after subsequent ripening for 4 days at 20 °C (shelf life). At harvest, treated fruits from both cultivars had higher weight and pulp firmness than control fruits, while no effect was observed for either colour, total soluble solid content (TSS) and titratable acidity (TA) or the time required to ripen on the tree. During cold storage, lower levels of weight loss, colour evolution, TSS/TA ratio and ethylene production and higher pulp firmness were found in treated peaches and nectarines compared with control fruits. Also, the storability of treated fruits was extended for up to 14 days more than that of control fruits. During ripening at 20 °C after different periods of cold storage, parameters related to ripening evolved faster in control than in treated fruits. Also, the occurrence of the climacteric peak of ethylene production was delayed and its intensity was lower in treated peaches and nectarines than in controls. Copyright © 2004 Society of Chemical Industry     

Sugars and organic acids in Japanese plums (Prunus salicinaLindell) as influenced by maturation, harvest date, storage temperature and period

The effects of fruit maturation, harvest date, storage temperature, storage period and shelf life, on the concentrations of individual sugars and organic acids in Japanese plums were investigated. During fruit maturation in 'Amber Jewel' plums, sucrose concentration increased significantly from 101 days after full bloom (DAFB) to 1 week after commercial maturity (136 DAFB) with a non-significant change in the concentration of total organic acids and malic acid, the major organic acid. The changes in concentrations of sugars and organic acids during cold storage of 'Amber Jewel' plums harvested on 129 and 136 DAFB appeared to be independent of harvest date. Storage of 'Amber Jewel' plums at 5 °C accelerated the loss of sucrose and increased the concentrations of fructose and glucose from the 4^th week of storage compared with those stored at 0 °C. 'Blackamber' plums did not undergo any significant increase in the total and individual sugars during 5 weeks storage and subsequent shelf-life of 8 days at 20 °C. Malic acid concentrations declined during storage from 3 weeks onwards with a further substantial loss during ripening at 20 °C. Maturation, harvest date, storage temperature, storage period and shelf-life affect the concentrations of sugars and organic acids in Japanese plums.     

Some postharvest factors associated with the occurrence of chilling injury in banana

Unripe Cavendish banana fruits were stored at 5–7°C under normal or 0.14 normal atmospheric pressure for two weeks, with or without a continuous supply of ethylene, prior to ripening at 20°C. Pulp/peel ratio, colour index and production of volatile were measured following prestorage at chilling temperature, and after reaching ripeness at 20°C. CO₂ and C₂H₄ production were also measured at 20°C. The results show that green fruits had lower pulp/peel ratios than treated green fruits while the reverse was true following ripening at 20°C. Yellow colour development was retarded by 5°C pretreatment, and low pressure storage had no noticeable effect on colour index. Prestorage at 7°C, however, improved colour development slightly. Acetates, butyrates and alcohol produced by fruits prestored at chilling temperature and 0.14 normal atmospheric pressure showed both qualitative and quantitative differences compared with those produced by non-chilled fruits.     

Quality improvement and extension of shelf life by 1-methylcyclopropene in plum as affected by ripening stage at harvest

Plum (Prunus domestica L. cv. ‘President’) fruits were harvested at two pre-climacteric stages of ripeness (stage 1 and stage 2), and then treated with 1-methylcyclopropene (1-MCP) at two doses (0.3 and 0.5 μl l⁻¹) followed by 1, 2, 3, 4 and 5 weeks of cold storage and their respective 7 days of shelf life at 20 °C. Both 1-MCP doses were effective in terms of ethylene inhibition during shelf life after cold storage, for both ripening stages. Similarly, lower weight losses, delayed colour changes, reduced softening rate and diminished ripening index were found in 1-MCP treated plums than in controls at both stages of ripeness. Hence, during cold storage and shelf life, the efficacy of 1-MCP on ethylene production, weight loss, pulp firmness and ripening index was dose-dependent, while for colour and respiration rate the dose-dependence was only found during shelf life. The storability of 1-MCP treated plums could be extended up to 4 weeks of cold storage plus 7 days at 20 °C, and only up to 1 week of cold storage plus 7 days at 20 °C for controls. Then, 1-MCP is an effective tool for quality improvement and extension of shelf life in plums, and fruit might be harvested in stage 2 of ripening, at which the most desirable organoleptic attributes had been developed on tree.     

Bananas — physiology and biochemistry of storage and ripening for optimum quality

Bananas (Musa spp.) are a major food crop of the humid tropics, and though edible cultivars are diverse and numerous, most of our knowledge of the physiology and biochemistry of these fruits relates to a few dessert cultivars of the AAA type, mainly of the Cavendish subgroup, which dominate the export trade between tropical and temperate zones. The preclimacteric period of banana fruits after harvest determines their transportability, and its duration is very sensitive to changes in fruit maturity, storage temperature, ethylene concentration, and other factors; progress in measurement and resolution of each of these effects is described. Changes in composition of the ripening fruits, especially in the development of flavor volatiles, are reviewed. Progress in understanding the integration of the biochemical changes controlling ripening in banana fruits is discussed. Recent work on storage, ripening, and factors relating to sensory assessment of fruit quality is discussed for cultivars of Musa types not used in major export trades.     

Effects of 1-MCP on chlorophyll degradation pathway-associated genes expression and chloroplast ultrastructure during the peel yellowing of Chinese pear fruits in storage

The peel yellowing is an important pigment physiological process of green fruit ripening, which mainly results from chlorophyll degradation in the fruit peel. In this work, two typical cultivars with different ripening speed, a slow ripening pear 'Emerald' (Pyrus bretschneideri Rehd. cv. Emerald) and a fast ripening 'Jingbai' (Pyrus ussuriensis Maxim. cv. Jingbai) were used to investigate the molecular mechanism of chlorophyll degradation in pear yellowing/ripening during postharvest storage. The fruits after harvest were treated with 1-methylcyclopropene (1-MCP), an ethylene action inhibitor at 1.0 μLl(-1) to determine its effect on chloroplast ultrastructure and the expression of chlorophyll degradation associated genes in peel tissues. Our results show that the pears treated with 1-MCP had a lower ethylene production rate and higher chlorophyll content compared to those of untreated fruit. The more intact chloroplasts with well-organised grana thylakoids and small plastoglobuli were maintained in the peel of 1-MCP treated fruit for up to 30 and 15 d in 'Emerald' and 'Jingbai', respectively. The expression of chlorophyll degradation associated genes: pheophorbide a oxygenase (PAO), non-yellow colouring (NYC), NYC1-like (NOL), stay-green 1(SGR1), was suppressed, while no significant change was found in chlorophyllase 1 (CHL1) and red chlorophyll catabolite reductase (RCCR) in both cultivar fruits treated with 1-MCP. These results suggest that 1-MCP can delay chlorophyll degradation by inhibiting ethylene production and suppressing the gene expression of PAO, NYC, NOL and SGR1, which are closely associated with chlorophyll catabolic pathway.     

温度和乙烯对京白梨后熟进程及其品质的影响

研究温度、乙烯对京白梨果实后熟进程及品质的影响。测定果实乙烯释放量、呼吸强度、果实硬度、可溶性固形物含量、pH值、果皮颜色ΔE 值和h 值、失重率、病果率等指标,并进行感官评价。结果表明：温度和乙烯直接影响果实的后熟进程和后熟品质;后熟过程中果实硬度与后熟时间呈极显著线性负相关(P＜ 0.01),温度过高或过低均导致果皮转色和果实硬度后熟不一致,适度的低温(14℃)延迟了果实乙烯峰值的启动时间,高温(28℃)抑制乙烯的生成和果实的软化,温度越高,失重率和烂果率越高;外源乙烯有助于果实乙烯的生成和呼吸强度的增加,乙烯加快了果实的后熟进程,并且后熟更均匀一致,且品质最佳。研究表明：京白梨后熟的适宜温度范围17～23℃,最佳温度20℃,最佳乙烯催熟用量为100μL/L。     

Effects of temperature on the ripening of mango fruit (mangifera indica L. var. tommy atkins)

The effects of temperature on the ripening of Tommy Atkins mango were studied. Ripening temperature can affect fruit colour, flavour and texture development differently. Fruits at 12°C did not ripen to full eating quality during the 16 days of the experiment. Sugar levels were comparable with those at other temperatures, but acid levels were higher; they retained some green coloration, had lower pulp carotenoids and showed incomplete softening. After 15 days at 17°C, fruits had softened and degreened to an acceptable level but had a poor pulp colour. They were comparatively high in sugars but were also high in acids, resulting in a low sugar:acid ratio. Fruits kept at 22, 27 and 32°C all showed the development of good quality characteristics of high chlorophyll breakdown, high pulp carotenoids, a good texture and a balanced sugar: acid ratio. Similar characteristics were shown at 37°C, although the peel generally appeared mottled and the pulp had slightly lower sugar:acid ratios.     

The effects of fruit maturation,delayed storage and ethylene treatment on the incidence of low‐temperature breakdown of ‘Hayward’ kiwifruit

BACKGROUND: Low‐temperature breakdown (LTB), a disorder inducing quality loss, during and after cold storage of ‘Hayward’ kiwifruit was investigated. Harvested kiwifruits during fruit maturation or after delayed storage (DS) at 20 °C for 0, 1, 2, 3 and 4 weeks and 1 µL L^?1 ethylene treatment for 24 h were stored at ? 0.5 °C for 24 weeks and additional ripening at 20 °C for 5 days. Fruit quality indices and LTB incidence and severity were determined before and after treatments. RESULTS: Harvested fruits ripened during maturation, DS and after ethylene treatment. After storage and shelf life, fruits of all treatments were at complete ripening stage. LTB incidence of early harvested fruits was high, while that of fruits of the mid (third) and late harvests was low. Fruits of the third harvest date showed progressively increased LTB incidence with increasing duration of DS to as high as 95–100% after 4 weeks. Ethylene‐treated fruits showed a comparable increase in LTB to that corresponding to 2–3 weeks of DS. CONCLUSION: In contrast to fruit maturation, postharvest (after harvest and before storage) DS at non‐chilling temperature and ethylene treatment advanced the ripening of ‘Hayward’ kiwifruit and resulted in increased LTB incidence. Copyright © 2012 Society of Chemical Industry     

Expression of genes associated with ethylene-signalling pathway in harvested banana fruit in response to temperature and 1-MCP treatment

BACKGROUND: Little attention has been paid to characterising the ethylene‐signalling pathway genes in relation to abnormal ripening of harvested banana fruit during storage at high temperature. The aim of the present study was to investigate banana fruit abnormal ripening and the expression of ten genes associated with the ethylene‐signalling pathway, namely MaACS1, MaACO1, MaERS1–4 and MaEIL1–4, at high temperature. Changes in these parameters of banana fruit at high temperature in response to 1‐MCP pretreatment were also investigated. RESULTS: High temperature accelerated the decline in fruit firmness, increased ethylene production and inhibited degreening in banana fruit, resulting in fruit abnormal ripening. In addition, the expression of MaACS1, MaACO1, MaERS2, MaERS3, MaERS4, MaEIL1, MaEIL3 and MaEIL4 was enhanced in banana fruit stored at high temperature. However, application of 1‐MCP prior to high temperature storage delayed fruit abnormal ripening and simultaneously suppressed the expression of MaACS1, MaERS2, MaERS3, MaEIL1, MaEIL3 and MaEIL4. CONCLUSION: The findings of this study suggested that the expression of genes associated with the ethylene‐signalling pathway might be involved in banana fruit abnormal ripening at high temperature. Application of 1‐MCP suppressed the expression of genes associated with the ethylene‐signalling pathway, which may be attributed at least partially to 1‐MCP delaying fruit abnormal ripening at high temperature. Copyright © 2010 Society of Chemical Industry     

Impact of shelf life on content of primary and secondary metabolites in apple (Malus domestica Borkh.)

In this study, we evaluated the changes in apple fruit quality during shelf life. After a month of cold storage, apples of cultivars "Jonagold" and "Golden Delicious" were exposed to ambient temperatures for 21 d, with subsequent sampling every 3 or 4 d. Fruit firmness, changes in amounts of sugars, malic acid, and phenolics were observed during shelf life. Chemical analyses were done with HPLC-PDA system. An interchange between various sugars was noticed, but in general, the sum of sugars remained at the same level. The content of malic acid remained stable or dropped, resulting in sweeter fruit. Levels of phenolics were more constant in the pulp of both cultivars analyzed, while in the peel, the changes were more pronounced. In the pulp, a peak in the content of hydroxycinnamic acids and flavanols was noticed on the 2nd or 3rd sampling and afterwards, the amounts remained constant. In the peel an initial decrease of all analyzed phenolic groups was observed in both cultivars, however it was more pronounced in "Jonagold." It can be concluded that changes in primary and secondary metabolites are not the main reason for the lower quality of fruit exposed to ambient temperatures. On the other hand, fruit firmness might be the limiting factor for shelf life duration.     

Rheological and functional properties of flours from banana pulp and peel

Unripe banana flour can be an alternative to minimize post‐harvest loss and to increase the aggregate value of banana fruit. Flour from unripe banana is rich in phytosterols and resistant starch, being proposed as health food. Flours from unripe banana peel and pulp were evaluated on their composition, phytosterols content, thermal and rheological properties, and pasting profiles. High amounts of β‐sitosterol, campesterol, and stigmasterol were found in flour from banana peel. These samples showed lower viscosity values of pasting profiles, lower energy enthalpy on gelatinization, and higher temperature of gelatinization than those ones from pulp. Anti‐oxidant treatment of fruits with citric acid does not change pasting profiles of flours from pulp, but resulted in slight increase in viscosity, suggesting that structure of starch could be modified by acidification.     

香蕉MaWRKY31转录因子的特性及对MaACS1、MaACO1和MaSAG1的调控

从香蕉果实中克隆得到1个WRKY转录因子,命名为Ma WRKY31。氨基酸序列比对及进化树分析发现Ma WRKY31具有一个典型的WRKY结构域,与拟南芥WRKY31和番茄Sl WRKY6同源性较高,且同属于第Ⅱ类b亚族。实时荧光定量聚合酶链式反应表明外源乙烯处理诱导了Ma WRKY31的表达,并且随着香蕉果实的成熟衰老,其表达明显增强。亚细胞定位和转录活性分析显示Ma WRKY31定位于细胞核,是一种核蛋白,并且具有转录激活活性。双荧光素酶瞬时表达分析显示,Ma WRKY31可以激活乙烯合成基因Ma ACS1和Ma ACO1,以及成熟衰老相关基因Ma SAG1的启动子活性。这些结果表明Ma WRKY31可能通过调控乙烯合成和成熟衰老相关基因的表达来参与香蕉果实成熟衰老过程,加深了对香蕉果实成熟衰老转录调控机制的认识。     

Maturity and ripening effects on chemical and sensory properties of apple juice

The effects of harvest maturity and ripening on the chemical composition and sensory characteristics of ‘McIntosh’ and ‘Spartan’ apple juice were evaluated. Juice was extracted from fruit harvested at seven weekly intervals beginning 3–4 weeks before commercial harvest and from fruit held in air storage (1°C) for 1 to 3 months. Internal ethylene concentration and starch index were used as maturity indices. Principal component analysis of juice data (pH. titratable acidity, organic acids, soluble solids, sugars, phenols, turbidity, and Hunterlab colour) showed a distinctive maturity effect on the characteristics of juice extracted from fruit immediately after harvest or after storage. Triangle testing showed aroma and flavour differences in both ‘McIntosh’ and ‘Spartan’ to be first discernable when ethylene was first detected (internal ethylene concentration ≥ 0.1 μl litre^?1) and starch hydrolysis evident (starch index 3.0–5.0 for ‘McIntosh’, 1.5–3.0 for ‘Spartan’), or after 2–3 months of air storage. Sensory profiling of fruity aroma, total aroma, fruit flavour by mouth, sweetness, and sourness in the juices showed increased fruitiness and sweetness and decreased sourness with advancing maturity.     

高压静电场处理对香蕉果实成熟生理的影响

以香蕉果实为试验材料,在(20±1)℃试验冷库中贮藏21d,贮藏期间用－100kV/m和－200kV/m的高压静电场连续处理并测定果实的呼吸强度、乙烯释放量、硬度、果皮颜色变化以及果肉淀粉和可溶性糖含量的变化。结果表明：连续高压静电场处理可以使香蕉果实的呼吸跃变和乙烯释放高峰提前,淀粉转化为糖的速度快而且比对照早,果皮叶绿素含量明显低于对照,同时处理后的果肉硬度下降,低于对照;并且－200kV/m处理组的效果要优于－100kV/m处理组。说明高压静电场连续处理促进了香蕉果实的成熟,尤以－200kV/m处理组比对照提前成熟4d。     

Effect of temperature on chlorophyllase activity, chlorophyll degradation and carotenoids of Cavendish bananas during ripening

Changes in chlorophyllase activity, chlorophyll and carotenoid content of Giant Cavendish banana fruit peel during ripening were measured at tropical temperatures (30–34°C) and at 20°C to relate them to the greenish and yellow colours of the fruit ripened at these temperatures. At 30–34°C bananas remained green on ripening due to incomplete chlorophyll degradation while at 20°C complete degreening occurred and fruits turned yellow. Peel total carotenoid content remained constant during ripening and did not change with temperature. Free xanthophylls decreased while xanthophyll esters increased on ripening. Chlorophyllase activity increased during ripening and paralleled the respiratory climacteric, although activity was not consistently related to the differential degradation of chlorophyll at these temperatures. Exogenous application of ethylene and ethrel accelerated ripening, but had no effect on chlorophyllase levels, chlorophyll degradation and carotenoid content of bananas ripened at either 30–34°C or at 20°C.