Improving quality of greenhouse tomato (Solanum lycopersicum L.) by pre- and postharvest applications of hexanal-containing formulations

From harvest to consumption, tomato (Solanum lycopersicum L.) fruit are exposed to several exogenous factors that enhance product deterioration. Phospholipase D is a key enzyme involved in membrane deterioration that occurs during fruit ripening and senescence. Hexanal, an inhibitor of phospholipase D has been successfully used for pre- and postharvest treatment of fruit, vegetables and flowers. In this study, effectiveness of pre- and postharvest application of an aqueous hexanal formulation and an enhanced freshness formulation (EFF) containing hexanal and other ingredients were evaluated by monitoring changes in quality parameters during postharvest storage of greenhouse tomatoes. Tomatoes subjected to preharvest spray with EFF containing 1 mM hexanal twice a week had better colour, and firmness than untreated fruit and hexanal formulation treated fruit. EFF treated tomatoes also showed low hue angle values indicative of enhanced red colour. Preharvest spray with 1 mM hexanal twice a week resulted in higher levels of ascorbic acid and soluble solids in fruit than those subjected to EFF treatment, and the control. Postharvest dip application of harvested tomatoes in 2 mM hexanal as EFF resulted in enhanced brightness and hue angle values, reduced red colour, increased fruit firmness and ascorbic acid content after 21 days of storage, indicative of better quality. The results suggest that hexanal has the potential to enhance shelf-life and quality of greenhouse tomatoes.     

库尔勒香梨采后特征品质的研究

摘要：库尔勒香梨贮藏在0℃、5℃、10℃、15℃、20℃,相对湿度：90～95%的环境中,测定香梨在贮藏过程中果实硬度、可溶性固形物含量及果皮色泽的变化,采用数值的极差及变异系数,研究采后库尔勒香梨的特征品质。结果表明：香梨采后贮藏于不同温度下,其硬度随着果实的成熟均呈现下降趋势,低温贮藏对硬度的下降有明显的抑制作用;可溶性固形物在不同贮藏温度下降不明显,特别是低温贮藏;果品色泽在各贮藏温度下,随着贮藏时间的延长,成熟度增加,有显著的变化。比较香梨果实硬度、可溶性固形物、色差的在整个贮藏期间的变化差异,色差的数值变化最为明显,对香梨采后品质及衰老具有明显的指示作用,可作为评价香梨果实采后品质变化的特征指标及采后衰老的重要指标。     

Changes in bioactive compounds and response to postharvest storage conditions in purple eggplants as affected by fruit developmental stage

Fruit maturity stage at harvest influences the response to postharvest storage conditions and bioactive compounds content. In this work fruit from two purple eggplant cultivars (Monarca and Perla Negra) were harvested at 12, 15, 18, 20 and 23 d after fruit set (designated as stages I through V) and changes in size, dry weight, calyx area, cell wall material (AIR, alcohol insoluble residue), firmness, respiration, and antioxidants (peel anthocyanins and pulp carotenoids, ascorbic acid, phenolics and chlorogenic acid) were determined. In a second set of experiments the postharvest performance of fruit harvested at stages I (“baby” eggplants), III and IV (traditional harvest stages) during storage at 0 or 10 °C was assessed. Fruit growth continued until late ripening in contrast to calyx expansion and peel anthocyanin accumulation, which were relatively earlier events. Fruit dry weight decreased between stages I and III, remaining constant afterwards. “Baby” eggplants had higher antioxidant capacity, chlorogenic acid (ChA), carotenoids and ascorbic acid contents than late-harvested fruit. ChA predominated in pulp placental tissues at stage I, spreading throughout the fruit core at as ripening progressed. No marked differences in dry mass, antioxidant capacity or responses to postharvest storage regimes were found between fruit harvested at stages III and IV. Late pickings increased yields and led to less dense fruit, which had lower respiration rates. Within this harvest window, storage at 10 °C maximized quality maintenance. In contrast “baby” eggplants stored better at 0 °C. Understanding the developmental changes in bioactive compounds and postharvest performance may help in the maximization of fruit antioxidant properties as well as in the selection of the optimal handling conditions for each ontogenic stage.     

Preharvest application of abscisic acid promotes anthocyanins accumulation in pericarp of litchi fruit without adversely affecting postharvest quality

Pericarp colour of litchi fruit is an important quality attribute that determines its market value and consumer acceptance. Plant growth regulators (PGR) such as abscisic acid (ABA) and ethephon are known to play important roles in peel colour development during maturation and ripening of non-climacteric fruits (e.g. grape and litchi). Our aim was to investigate the effects of preharvest application of ABA, ethephon and their combination on pericarp colour and fruit quality of litchi (cv. Calcuttia) and also to assess the potential effects on postharvest performance of fruit. Exogenous application of ABA (150 or 300 mg L⁻¹) at the colour-break stage significantly increased the concentration of total anthocyanins and cyanidin-3-O-rutinoside, the major anthocyanin contributing ∼71–96% of the total anthocyanins, in litchi pericarp compared to ethephon (500 μL L⁻¹). Among different anthocyanins quantified, the relative contribution of cyanidin-3,5-diglucoside to the total anthocyanins was significantly higher in all PGR-treated fruit compared to the control, but the concentration of cyanidin-3-O-glucoside was specifically enhanced by ABA. No significant effect on the concentrations of epicatechin, and quercetin-3-O-rutinoside was observed in response to PGR treatments. Ethephon (500 μL L⁻¹) treatment did not significantly increase the anthocyanin levels in pericarp, but it caused more degradation of chlorophyll pigments than control. Aril quality with regard to firmness, soluble solids and acidity was not significantly affected by PGR treatments, except that ethephon-treated fruit showed significant softening and lower acidity. Postharvest changes in fruit quality attributes including pericarp browning during cold storage at 5 °C for 14 d were mainly related to the storage duration effect, rather than PGR treatment. In conclusion, ABA treatment (150 or 300 mg L⁻¹) at the colour-break stage enhanced anthocyanins accumulation in litchi pericarp without adversely affecting postharvest quality and storage stability for 14 d.     

Aloe arborescens and Aloe vera gels as coatings in delaying postharvest ripening in peach and plum fruit

Recently harvested peaches and plums were coated with either Aloe vera or Aloe arborescens gels and allowed to ripen at 20 °C for six days. Both coatings significantly delayed ethylene production, the effect being higher in plum which had the highest ethylene production rates. Changes in quality parameters related to peach and plum postharvest ripening, such as colour changes, reduction of acidity and increasing in ripening index (total soluble solids/total acidity ratio), were significantly delayed in coated fruit. In addition, both coatings significantly reduced weight loss, especially the A. arborescens gel. Thus, A. arborescens gel could be even more effective than A. vera gel for use as an edible coating for preserving the quality of climacteric fruit.     

套小袋时期对‘翠冠’梨成熟果实内在品质及外观的影响

以‘翠冠’梨为试材,研究2次套袋中套小袋时期对梨果实内在品质及外观的影响。结果表明：总体来说,与CK相比,‘翠冠’梨成熟时,果实单果重增加;果实硬度降低;果实可溶性固形物含量与CK相比,4月22日套小袋、5月12日套大袋的A处理含量高（C黑除外）;果皮厚度厚;果点密度增加;果点直径减小;果面亮度增加;套黑袋的果面绿色度极低,果面黄色度也低,套白袋的果面偏绿、偏黄。同处理套黑袋的比套白袋的单果重小,果实硬度高,可溶性固形物含量高,果皮厚度厚,果点密度增加,果点直径小,果面亮度亮,绿色度低,黄色度低。总之,A处理效果较好,与CK相比,可溶性固形物含量高,果实硬度较高,A白果实单果重大,A黑果实单果重较大。     

Influence of exogenous ethylene during refrigerated storage on storability and quality of Actinidia chinensis (cv. Hort16A)

The kiwifruit industry was established on fruit of Actinidia deliciosa (‘Hayward’), which is known as a climacteric fruit with high sensitivity to ethylene. In recent times fruit from Actinidia chinensis have become a substantial component of the kiwifruit market. There is limited information about the sensitivity of A. chinensis to ethylene during refrigerated storage and hence current ethylene management practices for A. chinensis mimic those established for A. deliciosa. This research aimed to quantify the effect of ethylene during refrigerated storage on A. chinensis (‘Hort16A’) quality (firmness, colour and total soluble solids). Three grower lines were stored at 1.5 °C, 95% RH with ethylene in the range of 0.001-1 μL L⁻¹ applied to the environment after 3 weeks of storage for the remainder of storage (17 weeks). Fruit quality was assessed at regular intervals. Loss of firmness was found to be very sensitive to ethylene, with significant differences between fruit stored in 0.001 μL L⁻¹ (as a control) and 0.1 μL L⁻¹ occurring after 2 weeks of exposure. Fruit exposed to 1 μL L⁻¹ ethylene not only rapidly softened, but also increased in hue angle (greenness) and reduced in lightness (darkened) further reducing the quality of the yellow coloured kiwifruit cultivar. Total soluble solids were not heavily influenced by ethylene exposure, with grower differences being maintained throughout the experiment. This work demonstrates that A. chinensis (cv. Hort16A) fruit firmness and colour will be influenced by the ethylene conditions in a commercial storage environment by advancing ripening and senescence.     

Postharvest performance of the yellow-fleshed ‘Hort16A’ kiwifruit in relation to fruit maturation

Postharvest performance of fruit is dependent on the maturity or physiological state of the fruit at harvest in conjunction with the postharvest management applied. For yellow-fleshed kiwifruit, the flesh colour is a significant quality attribute, and for ‘Hort16A’, flesh colour has been used for timing harvest. Variability in the postharvest performance of ‘Hort16A’ kiwifruit suggests that flesh colour alone is not as strongly indicative of postharvest performance as soluble solids content (SSC) was found to be for ‘Hayward’ kiwifruit 30 years ago. The postharvest performance of ‘Hort16A’ kiwifruit, assessed as the fruit firmness and chilling injury expression during storage, has been associated with a range of fruit characteristics: flesh colour, SSC, firmness, seed colour, fresh weight, dry matter, starch and soluble carbohydrates measured at harvest throughout maturation. The changing responses of the fruit SSC to temperature, and softening to ethylene, have also been determined. The data illustrate the complex nature of ‘Hort16A’ fruit maturation, even when looking only at simple, easy-to-measure fruit attributes. While a yellow flesh colour is a commercial necessity for ‘Hort16A’ kiwifruit, flesh colour is not a robust indicator of postharvest performance and is not tightly linked to SSC or firmness. Changes in the capacity of fruit to respond to temperature or ethylene are not reflected in on-vine changes. Softening in storage is strongly linked to the softening rate occurring on the vine at the time of harvest. Any association between at-harvest characteristics and chilling susceptibility is less clear, and chilling tolerance appears more associated with the completion of growth and carbohydrate accumulation than with increased soluble solids accumulation rates as in ‘Hayward’. Approaches to extend the understanding of the link between maturation, harvest indices and postharvest performance are discussed.     

Non-destructive monitoring of flesh softening in the black-skinned Japanese plums ‘Angeleno’ and ‘Autumn beaut’ on-tree and postharvest

There is a need to develop alternative harvest indexes for black skinned plums. The aim of this research was to analyze and compare the most commonly used indexes for deciding the harvest date for Japanese plum, and evaluate the effectiveness of new approaches for studying maturation. The ripening process was monitored on-tree and during postharvest in a non-destructive way, through the absorbance of chlorophyll (I_AD), the compression strength of the intact fruit, and the traditional parameters associated with ripening. Fruit were harvested at commercial ripeness and “tree-ripe”, and were stored for 10 d at 22 °C and 75-80% RH. The I_AD decreased during the last phase of development of the fruit on-tree, and it was related to the common indexes used for plums. ‘Angeleno’ showed a decrease of the I_AD 24% lower than that observed for ‘Autumn beaut’. The I_AD versus time showed the highest coefficients of determination when compared with the soluble solids concentration (SSC), flesh firmness, hue (H°) and chroma (C*) of the skin. The compression strength of the intact fruit was associated with flesh firmness, and to a lesser extent with the SSC for ‘Angeleno’, whereas for ‘Autumn beaut’ higher correlations for both the SSC and flesh firmness were observed. The C* of the skin on ‘Autumn beaut’ showed an erratic change during ripening; by contrast, for ‘Angeleno’, this index showed a clear trend. During postharvest it was observed that for ‘Angeleno’ fruit picked at commercial ripeness, the rate of change of the I_AD was practically the same as observed on-tree, while for ‘Autumn beaut’ the rates of change on-tree and at postharvest were 0.075 I_AD d⁻¹ and 0.024 I_AD d⁻¹, respectively. For the “tree-ripe” fruit, the rate of change was practically the same for both cultivars. Similar trends were observed for the compression strength.     

Greenhouse climate control affects postharvest tomato quality

In this study, important quality properties such as firmness, sugar and acid levels were measured and analysed in tomatoes harvested from three greenhouses during a five month period and stored at 16 °C for over 20 days. Tomatoes were harvested from three identical, neighbouring, greenhouses which were either conventionally ventilated (open greenhouse) or mechanically cooled (semi-closed greenhouses). Sugar and acids levels were hardly affected by greenhouse type. Compared to the open greenhouse, semi-closed greenhouses produced heavier and less mature (firmer) fruit at the commercial harvesting stage based on colour. Fruit maturity differences could be linked to the vertical temperature gradient and to CO₂ levels in the different greenhouses. This indicates that CO₂ levels and temperature affect the synchronisation between colour and firmness maturity at harvest. The acceptance period, i.e., the time period both tomato colour and firmness are considered acceptable by consumers, will likely be positively affected when growers switch from conventionally ventilated to semi-closed production systems. Additional to greenhouse effects also effects of the harvest month were observed. The sugar to acid ratio was highest and glucose to fructose ratio was lowest in July, the month with the highest irradiance, irrespective of greenhouse type. The estimated value for the maximum firmness (F_max) varied from 17.9 N in August to 31.2 N in June. This monthly variation in F_max explains an important part of the variation found in the postharvest behaviour of tomatoes. Interestingly, the monthly variation in F_max showed the same trend as found for the monthly initial sugar levels. It might be hypothesised that the monthly variation in glucose and fructose levels causes variation in that part of firmness that is generated by cell turgor. The monthly variation in F_max, sugar and acid levels could not be linked to climate conditions and remains to be elucidated.     

1-MCP extends the storage and shelf life of mangosteen (Garcinia mangostana L.) fruit

Mangosteen (Garcinia mangostana L.) fruit were harvested when the peel (pericarp) was light greenish yellow with scattered pinkish spots. Fruit were exposed to 1 μL L⁻¹ 1-methylcyclopropene (1-MCP) for 6 h at 25 °C and were then stored at 25 °C (control) or 15 °C. The 1-MCP treatment only temporarily delayed softening of the fruit flesh, during storage. Storage life, defined as the time until the pericarp was dark purple, was much longer in fruit stored at 15 °C than in fruit stored at 25 °C. It was also longer in 1-MCP treated fruit (storage life at 15 °C: control 18 d, 1-MCP-treated fruit 27 d). The 1-MCP treatment also increased the length of shelf life, defined as the time until the pericarp turned blackish purple or showed calyx wilting, at 25 °C. 1-MCP treatment reduced ethylene production. It also reduced pericarp levels of 1-aminocyclopropane-1-carboxylic acid (ACC), and the pericarp activities of ACC synthase (ACS) and ACC oxidase (ACO). In the fruit flesh, in contrast, 1-MCP did not affect ACC levels and ACS activity, but the treatment reduced ACO activity. Taken together, both the storage life and the shelf life of the fruit were extended by the 1-MCP treatment. A decrease in ACO activity largely accounted for the effects of the 1-MCP on ethylene production in the pericarp.     

Effects of cold storage and shelf-life on sensory quality and consumer acceptance of ‘Abate Fetel’ pears

Fruit products certified by quality labels should guarantee high levels of consumer acceptance, despite the unavoidable variability arising from growing conditions and postharvest responses. The quality of ‘Abate Fetel’ pear (Pyrus communis L.) fruit was studied, after short or long cold storage, by analysis of physicochemical, texture and flavour traits, to investigate factors affecting consumer acceptance. Fruit from three orchards differing in location and design, monitored during 10 d of ripening at 20 °C, softened progressively to reach and exceed firmness adequate for consumption. Change in colour, in particular hue angle, paralleled softening. Sensory traits were investigated by evaluating fruit of three different firmness levels within the range of acceptable eating quality. Firmness differences were clearly perceived both by expert judges and by consumers, but did not influence the degree of liking. ‘Abate Fetel’ pear can maintain acceptable eating quality at 20 °C for 4–8 d after 13 weeks storage at ?1 °C, or 2–6 d after 23 weeks storage at ?1 °C. Changing texture parameters were perceived at eating, without compromising overall quality. Production system affected intrinsic quality parameters such as total soluble solids concentration, but did not influence consumer acceptance. In consumer tests conducted after 13 weeks of cold storage, high scores were recorded, with a 86% acceptance frequency and more than 40% of scores reflecting “like very much” or “like extremely”. After 23 weeks of cold storage a decrease in degree of liking was observed. The overall value of ‘Abate Fetel IGP Emilia-Romagna’ quality label was confirmed by consumer evaluations. However, the decrease in consumer acceptance after 23 weeks of cold storage indicates that caution should be used in using long storage durations.     

Colour at harvest and post-harvest behaviour influence paprika and chilli spice quality.

Capsicum annuum L. paprika and cayenne chilli pepper fruit were grown for red spice production and harvested at various colour stages on the same day. Fruit of each stage were allowed to change colour at room temperature with or without the addition of 100 μl l⁻¹ ethylene. Fruit appearance and colour development, and respiration and ethylene production were measured during the colouring period. Ethylene treatment had no effect on colour development or pungency for both cultivars, even though it easily crossed the cuticle, epidermis and flesh tissues into the fruit cavity. Green or deep green harvested fruit failed to fully colour red, while fruit that were harvested at or after the colour break stage visually completed their red colour development within 7–9 days. However, the colour intensity of spice powder was low for all fruit that had not developed a deep red colour prior to harvest. For paprika no difference between deep red fruit that were succulent or that had partially dried on the plant was found, but chilli fruit that had partially dried before harvest produced the most intense colour. American Spice Trade Association (ASTA) extractable red colour was the best measure of spice colour quality, compared to reflected lightness (L*), chroma (C*) and hue angle (h°) colour measurements. Pungency did not change between ripeness stages for chilli and was absent in paprika. Paprika and chilli fruit showed climacteric behaviour as long as they were attached to the plant, but when detached were non-climacteric.     

Changes in antioxidant activity and postharvest quality of sweet pomegranates cv. Hicrannar under modified atmosphere packaging

The effects of different modified atmosphere packaging (MAP) on antioxidant compounds and storage quality of ‘Hicrannar’ sweet pomegranates were investigated during long term storage. Pomegranates were harvested at the commercial harvest stage and packed in two different types of MAP (MAP1 and MAP2). After packaging, all fruit were stored at 6 °C and 90–95% RH for 120 days, then removed from storage for different quality analyses. Some fruit were kept at 20 °C for 3 days to simulate a period of shelf-life. Fruit weight loss, decay index, skin color, total titratable acidity, total soluble solids content, total phenolics, total anthocyanins and antioxidant activity were determined. Internal atmospheres created by the MAP were periodically assessed during cold storage, and CO₂ concentrations increased and O₂ concentrations decreased inside the MAP. MAP significantly reduced weight loss after both 120 days of cold storage and shelf-life. MAP2 was the most effective packaging in reducing weight loss. Storage of pomegranates in MAP also reduced decay and the decay index, and maintained visual appearance compared to control fruit. During storage, a decrease in L* and C* values and an increase in h° values were observed in all treatments. However, fruit stored in MAP2 had higher L*, C* and lower h° values than in other treatments. Titratable acidity and total soluble solids decreased after cold storage and shelf-life, and no significant differences among treatments were found. Total phenolics, total anthocyanin contents and antioxidant activity increased during the storage period in control fruit.     

Methods to analyze physico-chemical changes during mango ripening: A multivariate approach

Canonical discriminant analysis (CDA) was used to identify the best method to discriminate between maturity and ripening stages, assessed in terms of dry matter content, firmness, color (peel and flesh), total soluble solids content attributes, before and during ‘Keitt’ mango ripening at 20 °C. Dry matter content was determined by hot-air oven and microwave oven methods. Fruit firmness was determined non-destructively by hand squeezing, with a durometer, using acoustic resonance and low-mass elastic impact methods (AWETA), as well as destructively by the penetrometer. Peel and flesh color were expressed as L*, a*, b*, h⁰ and C* values. Total soluble solids content was analyzed from filtered juice from whole fruit tissue and from unfiltered juice squeezed out by hand. Canonical discriminant analysis indicated that the durometer and the penetrometer were better methods to assess firmness than hand firmness, acoustic resonance or impact methods. The best color attributes to follow changes during early stage of ‘Keitt’ mango ripening were a* and b* values of the flesh, whereas b* value of the peel was considered better during later stages of ripening. Results of total soluble solids content in filtered juice from whole fruit tissue were less variable compared to unfiltered juice squeezed out by hand. Dry matter content was better assessed by drying the sample in a microwave oven than in a hot-air oven. A combined CDA including the best methods to assess each ripening attribute, as well as titratable acidity, showed that the best tools to assess changes in fruit during ripening were the penetrometer, followed by flesh a* value and total soluble solids content (from filtered juice from whole fruit).     

Integration of pre- and postharvest treatments for the control of black spot caused by Alternaria alternata in stored persimmon fruit

In Israel, black spot caused by Alternaria alternata is the main postharvest factor that impairs the quality and reduces the storability of persimmon fruit (Diospyros kaki cv. Triumph). The fungus infects the fruit in the orchard and remains quiescent until harvest. After harvest, the pathogen slowly colonizes the fruit during storage at 0 °C, which elicits black spot symptom development 2–3 months after storage entry. A commercial postharvest dip treatment in chlorine at 500 mg L^?1, released from sodium troclosene tablets, effectively controlled black spot in fruit stored for up to 2 months. However, decay incidence increased as the length of storage was extended beyond 2.5 months. The long incubation period that precedes black spot symptom development after harvest enabled the development of a series of integrative approaches for application at the pre- and postharvest stages, in combination with the commercial chlorine dip treatment, to improve the control of black spot disease. Preharvest treatments included treatment with the cytokinin-like N₁-(2-chloro-4-pyridyl)-N₃-phenylurea (CPPU) 30 d after fruit set, or a single spray with the curative fungicide polyoxin B 14 d before harvest, and when one of these was applied in combination with the postharvest chlorine dip treatment, the black spot infected area was reduced by 3 and 60%, respectively, compared with the chlorine dip alone. At the postharvest stage, fogging during storage, or post-storage on-line spraying with sodium troclosene, when applied in combination with the postharvest chlorine dip, improved the percentage of marketable fruit by 2 or 10%, respectively, compared with the chlorine dip alone. The results indicate that postharvest pathogens that show a slow colonization pattern might enable the integration of pre- and postharvest disease control methods to improve quality and reduce postharvest disease development.     

丁香和石菖蒲提取物对采后芒果贮藏品质的影响

摘 要：以“台农1号”芒果（Mangifera indica L.cv.Tainung No.1）为材料,研究了丁香和石菖蒲丙酮提取物处理对芒果在常温（28℃～30℃）贮藏条件下果实品质的影响。结果表明：与对照相比,丁香提取物处理显著降低了果实的失重率和病果率,延缓了果皮颜色的转黄,保持较高的果实硬度,能够显著延缓芒果VC含量的降解和TSS含量的积累,维持芒果果实较高的品质和风味。在降低果实的病果率,延缓果皮颜色的转黄方面,石菖蒲提取物处理作用比较显著,但显著促进了芒果果实的软化,VC含量的降解和TSS含量的积累,降低芒果果实的品质和风味。从综合保鲜效果来看,丁香蒲提取物要优于石菖蒲提取物。     

Quality changes in sapote mamey fruit during ripening and storage

Physical and chemical changes in sapote mamey (Pouteria sapota (Jacq.) H.E. Moore and Stearn) fruit during ripening and storage at various temperatures were evaluated. Ripening was associated with flesh softening, an increase in soluble solids content (SSC), and a change in flesh color from yellow or pale pink to a dark pink or red. No changes in fruit skin color or in flesh acidity were observed as ripening progressed. Ripe fruit had 30% or higher SSC, orange or red flesh (hue angle=52; chroma=45; L=60), acidity of 6–8 mM H⁺, and flesh firmness (compression force) ≤50 N. Flesh turned brown (L* value declined) in overripe fruit. Fruit held at 27, 25, or 20°C ripened in 3.5, 5 or 7 days after harvest, respectively. Fruit kept at 10°C showed minor changes in color and firmness and a slow rate of SSC increase. Fruit stored at 10 or 15°C and then ripened at 20°C had portions of the flesh with a much higher firmness and poorer development of red color compared to other parts of the fruit. This uneven ripening was probably a result of chilling injury. The number of fruit with injury was higher at 10°C than at 15°C, and increased with storage time. The rates of fruit weight loss relative to the initial fruit weight were 0.58, 0.98 and 1.83% d⁻¹ at 10, 20 and 27°C, respectively.     

Postharvest pigmentation in red Chinese sand pears (Pyrus pyrifolia Nakai) in response to optimum light and temperature

The development of red color in the peel of red Chinese sand pears (Pyrus pyrifolia Nakai) is influenced by temperature and light; however, the response patterns vary among different cultivars. In this study, we systematically investigated the influence of postharvest treatment with various temperatures (low, high, variant and constant) on detached mature fruit of red Chinese sand pear ‘Mantianhong’ and ‘Meirensu’. Fruit of red apple (Malus domestica Borkh.) ‘Royal Gala’ and red European pear (P. communis L.) ‘Cascade’ received the same treatments for comparison. Furthermore, the effects of light quality and irradiance level on ‘Mantianhong’ pears were evaluated at the optimum temperature for anthocyanin accumulation. Fruit firmness and concentrations of total soluble sugars and organic acids were measured to determine fruit quality. The effect of temperature on red Chinese sand pear fruit color was similar to that of apples, but not European pear. Moreover, low temperature more effectively induced red coloration in ‘Mantianhong’ and ‘Meirensu’ pears than high temperature; anthocyanin levels increased with increasing irradiance level from 0 to 532 μmol m⁻² s⁻¹, and UV-B and visible light synergistically improved the red color of the fruit. Therefore, a combination of low temperature and high intensity of UV-B/visible light could improve the postharvest coloration of red sand pear fruit. The results will contribute to an improved understanding of the mechanism responsible for the coloration of red Chinese sand pears and will aid development of new techniques to improve color in postharvest fruit.