Optimising quality-parameters of apple cv. ‘Pigeon’ by adjustment of nitrogen

To improve the productivity and quality of the apple cultivar ‘Pigeon’ the influence of 5 fertigation levels (14, 42, 70, 112, 224 mg N/l) and 3 widths of herbicide strip (0.2, 0.5, 1.0 m) were investigated on growth, yield and post-harvest quality/colour development of fruit. ‘Pigeon’ apples are picked when ca. 20% of the fruit skin has turned red, the fruit are then exposed to a sunning period on the orchard floor of 2–3 weeks to enhance red colour development (80% red skin); however the internal quality deteriorates during this period. Fruit drop occurs if fruit are left on the tree to develop colour. This study focused on how to reduce the length of the post-harvest sunning period to maximise both colour development and fruit quality. It was demonstrated that 14 mg N/l resulted in a low yield, small fruit, low vegetative growth, and low N content in leaf dry matter, but good fruit colour development. Excessive N fertigation (224 mg N/l) did not produce the significantly highest yield or the largest fruit, but it did enhance vegetative growth and resulted in less fruit colouration. N fertigation influenced optimal picking date; higher N fertigation delayed the time of picking, and increased the incidence of green fruit. Fruit from the high-N treatments required more days of post-harvest sunning to obtain the comparable red skin colour than fruit from the lower N-treatments. However, when all treatments were picked at ca. 20% fruit coloration it was not possible to reduce the length of post-harvest sunning period by N-supply. Most of the post-harvest colour development occurred within the first 6–9 days following harvest; colour developed on both sides but was enhanced on the shade side of the fruit. The shade side of the fruit had a greater potential for better red colour development than the blush side of the fruit.     

The Relation Between Time of Picking and Storage Disorders in Cox’s Orange Pippin Apple Fruits

In four successive seasons. Cox’s Orange Pippin apples were picked at weekly intervals and stored under various conditions to assess the effect of time of picking on wastage from different causes.

Mean fruit weight increased by up to 20% over the 6 to 10 weeks of the picking periods.

The maturity of the fruit when picked was assessed by following the respiration pattern of samples kept at 12°C.

The results for successive pickings of fruit kept at 37°-38° F. (2.8°-3 ·3° C.) (normal cold storage temperature for Cox) and all removed from store at the same time, showed more core flush in early-picked apples, and more senescent breakdown and rotting in late-picked apples. There was no sudden change in liability to any of these disorders which could be associated with any particular stage of maturity. There were no consistent effects of time of picking on the amount of bitter pit or on weight loss during storage.

Storage at 32° F. (o° C.) (below the recommended temperature for the storage of Cox’s Orange Pippin) resulted in low temperature breakdown. This disorder tended to be less severe in apples picked just before the climacteric rise in respiration rate.

It is concluded that, for any particular orchard, picking date should be based not only on maturity as judged by colour and size, but on the expected liability of the fruit to disorders, such as core flush and rotting due to Gloeosporium, and on the type and period of storage required.     

Effect of storage temperature on ripening and quality of custard apple (Annona squamosa L.) fruits

Summary

The effect of storage temperature on ripening, shelf life and chemical composition of custard apple (Annona squamosa L.) fruits stored at 10,15,20 and 25°C was studied. The safe range of storage temperature was found to be between 15 and 20°C, with maximum shelf life at 15°C. The ripening of fruits was observed on days 4, 6 and 9 of storage at 25,20, and 15°C respectively. The colour of the pulp, texture, taste and flavour of ripe fruits held at 25 and 20°C were superior followed by fruits stored at 15°C. At 10°C, the fruits became hard with surface blackening, messy pulp and less sweetness. The major changes during ripening were a continuous decrease in fruit firmness and starch content and a continuous increase in TSS and sugars, the changes being more rapid at 25 and 20°C than at 15 and 10°C. The acidity and ascorbic acid contents increased slightly during the initial stages of ripening followed by a decline, in the fruits stored at different temperatures. Custard apple fruits stored at 25 and 20^CC had a clear climacteric peak whereas those stored at 15 and 10°C did not show any distinct rise in respiration rate. Ethylene peak (2.40 µl kg^–1 h^–1) coincided with the respiratory climacteric at 25^CC storage, corresponding with the peaks in TSS, sugars, ascorbic acid and acidity.     

Changes during the ripening of the very late season Spanish peach cultivar Calanda: Feasibility of using CIELAB coordinates as maturity indices

Physiological maturity of peach at harvest greatly influences the post-harvest quality. Changes in colour during the last ripening stages of a very late and firm peach cultivar [Prunus persica (L.) Batsch cv. Calanda] have been studied to assess the feasibility of using reflectance colour references as non-destructive indices of maturity. The respiratory peak was simultaneous to the ethylene rise, and both induced important changes in the peaches. The physiological changes brought about a rise in polyphenoloxidase and peroxidase enzyme activity. The amount of carotenoids increased as maturity advanced and more markedly at the climacteric rise. Reflectance spectra and CIELAB coordinates reflected changes in skin and pulp colour and a^* and h_ab evolved nearly in a near linear way. Values of the b^* coordinate show changes as well. These findings agree with and extend previous results that reflectance changes can be used as reliable indices to establish the time of physiological maturity in Calanda peaches.     

A label-free quantitative proteomic investigation reveals stage-responsive ripening genes in apricot fruits

Apricot (Prunus armeniaca L.), a member of the Rosaceae family, with favorable nutritional and flavour quality, exhibited the characteristic climacteric changes during the fruit ripening process in ‘Shushanggan’ apricot. To further confirm the ripening-related genes in apricot, we combined quantitative proteomic tools with bioinformatics to investigate the expression profiles of ripening genes involved in significant biochemical and metabolic changes during ripening stages. The results showed that physiological traits of apricot fruits varied significantly at three different ripening stages, with remarkable correlation with fruit quality changes. Furthermore, 128 stage-specific proteins that are differently expressed in a stage-responsive manner in ripening apricot fruits were identified. Hierarchical clustering of stage-responsive proteins also revealed the metabolic changes in accordance with fruit ripening. Hence, a link has been established between protein profiles and ripening phenotypes which will help to improve our understanding of apricot fruit ripening at the proteomic level.     

Effects of water deficit during stage II of peach fruit development and postharvest on fruit quality and ethylene production

Summary

This study examined the hypothesis that enhancement of peach quality resulting from Regulated Deficit Irrigation (RDI) is caused primarily by changes in fruit physiology during development. Water deficit was applied during either stage II of fruit development (RDI-SII) or during stage II and postharvest (RDI-SII-PH), as compared with non-droughted (control) and postharvest (RDI-PH) treatments. Fruit from the various RDI treatments had significantly higher soluble solids concentrations and red colour at harvest than control fruit. While fruit respiration was not altered by any RDI treatment, ethylene production indicated sooner the onset of climacteric phase for fruit from RDI-SII and RDI-SII-PH than for control or RDI-PH fruit. Accordingly, greater ethylene production in detached fruit was related to their having experienced water stress during development. Ethylene production by RDI-PH fruit did not change, but their quality did in terms of increased soluble solids concentration and improved skin colour similar to the RDI-SII treatment. This observation suggests that water-stress related changes occurring during fruit development are not the only factors involved in enhancing quality in RDI fruit.     

枸杞呼吸特性研究

对枸杞生长发育过程中呼吸速率的变化及不同成熟度浆果在不同温度贮藏过程中的呼吸速率、细胞膜透性、失水率变化进行研究。结果表明:在枸杞生长发育过程中以及贮藏过程中随贮藏时间延长均无呼吸高峰出现,认为枸杞可能为非呼吸跃变型果实,同时在低温条件下不同成熟度浆果细胞膜透性、失水率上升较缓慢。     

鲜枣采后生理及贮藏研究进展

枣（ZizyphusjujubaMill．）原产中国。鲜枣富含维生素C,营养价值高,果实一经变软,维生素C几乎全部被氧化。鲜枣果实具有独特的采后生理特点,贮藏保鲜难度较大。综述了80年代以来国内外在鲜枣采后生理包括果实形态、呼吸类型、内源激素、软化机理及营养成分变化等方面的研究进展,介绍了影响鲜枣贮藏寿命的外界因子及内在因素。     

Influence of a pre-harvest reflective orchard mulching film on lipid peroxidation and anti-oxidant activity in apple fruit during post-harvest storage

Summary

Studies have shown that applying a reflective film to the floor of an orchard enhances fruit colouration. Here we assessed whether this practice also prolonged the post-harvest storage life of apple (Malus domestica Borkh cv. Fuji and Malus prunifolia [Willd.]) fruit. Strips of reflective mulching film (RMF) were placed beneath the apple trees and RMF-treated fruit were compared with those from untreated control (CK) trees. Enzymes involved in reducing lipid peroxidation such as superoxide dismutase (SOD) and catalase (CAT) are associated with delaying fruit senescence. Their activities, as well as malondialdehyde (MDA) concentrations, were quantified as indicators of physiological changes related to lipid peroxidation and membrane damage in the peel and flesh of RMF-treated or control apple fruit during 50 d of post-harvest storage at 4ºC. SOD activities increased in the peel and flesh from RMF-treated fruit during the first 40 d post-harvest, but declined significantly during the final 10 d of storage. RMF treatment resulted in increases in CAT activities of 5 – 14% and 16 – 29% in the peel and flesh of RMF-treated apples, respectively, compared with untreated CK fruit. Conversely, MDA concentrations were 7 – 23% and 14 – 30% lower in the peel and flesh, respectively, of RMF-treated fruit than in CK fruit over the 50 d storage period. Similarly, RMF treatment resulted in reductions of 7 – 20% and 3 – 10% in saturated fatty acid (SFA) concentrations in the peel and flesh, respectively, compared to CK fruit, while the corresponding polyunsaturated fatty acid (PUFA) concentrations increased by 2 – 10% and 3 – 7%. In conclusion, the use of RMF in apple orchards appears to be an effective technique to delay post-harvest senescence in apple fruit.     

Involvement of 1-methylcyclopropene in ripening of harvested mei (Prunus mume) fruit

Summary

Harvested mei (Prunus mume) fruit were stored at 20°C after exposure to 500 nl l^–1 1-methylcyclopropene (1-MCP) for 8 h. Firmness, peel colour, chlorophyll content, chlorophyllase activity, soluble solids content (SSC), titratable acidity (TA), respiration and ethylene production, and cell wall hydrolysis enzyme activities were monitored to determine the efficacy of 1-MCP treatment in delaying mei fruit ripening compared to untreated control fruit. Results showed that control ‘daqinghe’ mei fruit displayed typical climacteric patterns of respiration and ethylene production. Peak CO₂ production and ethylene production were observed after 6 d. Fruit softening was accompanied by a progressive decrease in colour parameters expressed as hue angle (h°), chlorophyll content, SSC, TA and increases in chlorophyllase, pectin methylesterase (PME) and polygalacturonase (PG) activities. 1-MCP treatment prior to the climacteric increase significantly delayed the onset of the climacteric peaks of CO₂ and ethylene production. These delays were associated with reductions in fruit softening, consistent with delaying the activities of PME and PG. Fruit treated with 1-MCP exhibited less peel colour change from green-to-yellow because of their lower levels of chlorophyllase activity and less chlorophyll breakdown. Moreover, 1-MCP treatment also significantly retarded reductions in SSC and TA compared with control fruit. The shelf-life of mei fruit ripening was increased by 4 d following 1-MCP treatment. Thus, 1-MCP treatment can markedly extend the post-harvest life of ‘daqinghe’ mei fruit.     

Polyphenoloxidase activity during ripening and chilling stress in ‘Manila’ mangoes

Summary

‘Manila’ mangoes were stored at 6 or 12°C, while a control lot was ripened at 258C. Polyphenoloxidase activity was measured in pulp and peel of mangoes during normal ripening and chilling-stress conditions. Compositional parameters (textural hardness, pH, acidity, and soluble solids) were monitored during ripening and chilling injury (CI) was assessed by visual inspection. PPO activity increased in refrigerated mangoes but fruit stored at 6°C displayed greater activity than those stored at 12°C. Both temperatures produced a peak in enzyme activity at day 16 of storage. Peel browning and acidity correlated with PPO activity (r.=.0.9073 and 0.9818) at 6°C. After the PPO peak was observed at day 16, refrigerated mangoes showed lower enzyme activities; however external browning became more pronounced.     

The effect of temperature on certain chemical changes and the storage behaviour of jujube fruits (Zizyphus spinachristi (L.), Willd.)

Summary

Jujube fruits (Zizyphus spinachristi (L.) Willd.) cv. Bambawi were harvested at the mature green stage and stored at 10°C and 27–30°C. Titratable acidity and total chlorophyll decreased as the fruit matured, the rate of decline being more rapid at the higher temperature. Total soluble solids, carotenoids and ascorbic acid contents of the fruit increased towards maturity, the increase being faster at the higher temperature. Jujube fruits could be stored for six days at room temperature and twenty-five days under refrigeration at 10°C.     

核桃果实成熟过程中呼吸速率与内源激素的变化

对核桃颗粒成熟过程中呼吸速率,乙烯释放量和内源激素ＩＡＡ（吲哚乙酸）、ＡＢＡ（脱落酸）、ＧＡ３（赤霉素）、ＺＲ（玉米素核苷）、Ｚ（玉米素）含量的变化进行了测定,结果表明,除种仁中Ｚ含量较上,青皮中其它激素水平均高于种仁。随着颗粒的成熟,ＩＡＡ、ＧＡ３、Ｚ、ＺＲ含量及乙烯释放量均呈下降趋势;而青皮中ＡＢＡ含量则逐渐增加。果实成熟后青皮中ＧＡ３和种仁中Ｚ含量明显增长,颗粒乙烯释放量明显增高,而采后果实     

Storage conditions and ripening of the custard apple Annona squamosa L.

Annona squamosa is a climateric fruit in which maximal carbon dioxide production preceeds that of ethylene during post-harvest storage. Normal ripening occurred at temperatures between 15 and 30° C, although the fruits were susceptible to fungal attack at temperatures above 25° C. Storage temperatures below 15° C caused chilling-injuries. Ripening was enhanced by removal of carbon dioxide and by addition of oxygen to the storage atmosphere, and delayed by the addition of carbon dioxide or removal of oxygen. Ethylene had no apparent effect on ripening. Fruits maintained under low relative humidities ripened faster than those stored under high-humidity conditions. Dipping the fruits in a solution of indole acetic acid at concentrations between 10^?4 and 10^?2 M accelerated ripening. Levels of both ascorbic acid and glucose increased to a maximum at the climacteric, but decreased as the fruits became over ripe. The stage of “eating” ripeness occurred at the climacteric. Recommended conditions for storing custard apple are: temperatures between 15 and 20° C, low oxygen and ethylene tensions coupled with 10% carbon dioxide and a relative humidity of 85%–90% in the storage atmosphere.     

Changes in sugars,starch and amylase activity during development of mango fruit cv Dashehari

The fruit weight of cv Dashehari mangoes increased until 91 days after fruit set, together with gradual increases in fructose and reducing sugars. Glucose, fructose and sucrose were identified in the dried mango pulp, glucose and fructose being more plentiful until maturity, whereas later (96–105 days) sucrose was predominant. There was an increase in the total sugar content after 72 days from fruit set. Starch accumulation was slow at first but later increased with a concomitant acceleration of amylase activity. A decline in both starch content and amylase activity was recorded after 91 days growth. The protein content decreased until 44 days after fruit set and then increased during 96 days of further development.     

Emulsion coatings control fruit fly and anthracnose in mango (Mangifera indica cv. Manila)

Summary

The potential effect of a hydrodispersion of maltodextrin, carboxylmethylcellulose, propylene glycol and sorbitan esters, on the reduction or prevention of spoilage caused by the fungus Colletotrichum gloeosporioides which produces anthracnose and by the fruit fly Anastrepha oblicua, was investigated as a coating for mango (Mangifera indica cv. Manila) fruit from commercial orchards in Jalcomulco, Veracruz, México. Coated and control mangoes were stored at 15 and 25?C and 85±5% r.h. Every 3 d, the coating was removed by washing with water, to determine the time necessary to minimize the damage caused by the anthracnose and the fruit fly larvae. In uncoated mangoes, larval growth and anthracnose manifestation occurred within 6 d at both storage temperatures. In coated mangoes, fruit fly larvae proliferation was avoided and anthracnose incidence was reduced. The results suggested that coatings should be remained for 9 d to avoid fruit fly larvae proliferating and minimize anthracnose incidence by 70%. Applying coatings may be part of a set of superficial treatments to guarantee the phytosanitary certification of tropical fruits such as mangoes.     

X-ray imaging for detecting spongy tissue,an internal disorder in fruits of ‘Alphonso’ mango (Mangifera indica L.)

An internal physiological ripening disorder, “spongy tissue”, affects about 30% of ‘Alphonso’ mangoes, the most popular Indian cultivar. Fruits show no external symptoms at harvest or on ripening but cutting reveals internal damage to the mesocarp which adversely affects fruit quality. Both fully grown green, unripe mangoes and ripe fruits show spongy tissue. A non-destructive x-ray inspection method has been developed to detect affected mangoes. X-ray photographs and x-ray images of fruits having spongy tissue show dark grey patches corresponding to internal cavities in contrast to light grey areas of healthy flesh. The method could be used for quality control for on-line detection and separation of mangoes having spongy tissue prior to packaging, by monitoring x-ray screen images.     

Effect of temperature on seed and fruit development in three mango (Mangifera indica L.) cultivars

The effect of diurnal maximum/minimum (20/10 or 25/15 °C) temperatures on seed and fruit development of ‘Irwin’, ‘Kensington’ and ‘Nam Dok Mai’ mangoes (Mangifera indica L.) was studied in a controlled-environment glasshouse. Exposure to low temperatures (20/10 °C day/night) 3 days after hand pollination significantly increased the percentage of stenospermocarpic fruit (nubbins), in which embryos were aborted at some stage during early fruit development. There were significant differences between cultivars in the percentage of nubbins produced out of the total fruit set following overnight exposure to 10 °C with 21% for ‘Nam Dok Mai’, 11% for ‘Kensington’ and 3% for ‘Irwin’. At 45 days after pollination, nubbin fruits were much smaller in size and weighed ca. 50% less than normal fruits. The lower percentage of nubbin fruits in ‘Irwin’ implies a greater adaptation to cool temperatures by this cultivar during fruit set and early embryo development.