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.     

Responses of banana fruit to pro-long coating at different times relative to the initiation of ripening

Coating banana fruit with Pro-long 24 h after initiation of ripening decreased their skin permeability to gases and depressed their O₂ content. Coating the fruit immediately before ripening initiation delayed the onset of rapid ethylene production, which normally begins as the fruit start to ripen. Coating slightly suppressed rapid C₂H₄ production when applied immediately after ripening initiation, and exerted a strong, temporary inhibition of C₂H₄ production when applied 24 h later. A climacteric rise in respiration was absent from fruit coated with Pro-long immediately before or after ripening initiation; delaying coating by a further 24 h arrested development of the climacteric in mid-rise. In mid-climacteric fruit, inhibition of C₂H₄ production by coating occurred more rapidly than inhibition of respiration. Coating the fruit delayed the chlorophyll loss which normally accompanies ripening, but the magnitude of this effect declined as the coating treatment was delayed relative to ripening initiation. The effects of coating on skin colour change and on respiration appeared to be largely independent of its effect on the fruit's C₂H₄ content.     

Changes in antioxidants and fruit quality in hot water-treated ‘Hom Thong’ banana fruit during storage

The effects of hot water treatment on antioxidants and fruit quality were investigated in banana fruit of cv. Gros Michel (Musa acuminata, AAA Group, locally called cv. Hom Thong) by immersing fruits in hot water (50 °C) for 10 min, before storage at 25 °C for 10 days or 14 °C for the first 8 days followed by storage at 25 °C for the second 8 days until ripening. Quality parameters including peel color and pulp firmness indicated that hot water treatment helped to delay banana fruit ripening at both storage conditions. Hot water treatment decreased the levels of hydrogen peroxide (H₂O₂) and malonydialdehyde (MDA) during storage at 25 °C. Glutathione (GSH and GSSG) contents and the ratio of GSH/GSSG during fruit approaching ripening were significantly induced in hot water-treated fruits while ascorbic acid (AA) contents were slightly increased. In addition, the combined treatment increased free phenolics and flavonoids during storage. Results suggest that hot water treatment has led to an induction of antioxidants in banana fruits as indicated by an increase of antioxidants and a decrease of H₂O₂ during ripening, and all of which result in a delayed ripening of banana fruit.     

Storage conditions and ripening of papaya ‘Bentong’ and ‘Taiping’

The optimum storage and ripening temperature for the 2 cultivars was approximately 20°C. Both cultivars ripened earlier after exogenous application of C₂H₄ combined with the removal of CO₂. The storage life of the fruits could be extended by maintaining them in an atmosphere devoid of C₂H₄ but containing 5% (v/v) CO₂ and with a high relative humidity. Chilling-injuries occurred at temperatures below 15°C when the papayas were stored for more than 7 days. The nutritional value of ripe fruit decreased rapidly with prolonged storage. At the “eating-ripe” stage, the glucose, protein and ascorbic acid contents were 2.23 g, 209 mg and 33 mg per 100 g pulp in ‘Bentong’, and 2.15 g, 196 mg and 30 mg per 100 g pulp in ‘Taiping’, respectively.     

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.     

Influence of ethanol on ethylene biosynthesis and flower senescence of cut carnation

Ethanol in the holding-solution inhibited climacteric ethylene (C₂H₄) biosynthesis and decreased the respiration rate 60% during a 7-day period in cut carnation flowers. Conversion of 1-aminocyclopropane-1-carboxylic acid (ACC) to C₂H₄ was inhibited by adding ethanol to the holding-solution. Simultaneously, ACC-induced senescence in carnation flowers was inhibited by ethanol. Ethanol was the most effective alcohol in delaying carnation flower senescence of the tested series methanol, ethanol, propanol, tert-butanol and n-butanol. Ovary development was also inhibited in carnation flowers by ethanol. The senescence of Easter lily flowers (Lilium longiflorum) and tulip flowers (Tulipa gesneriana) was not delayed by ethanol.     

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.     

Reduction of chilling injury in ‘Tommy Atkins’ mangoes during ripening

Studies were conducted to investigate how harvest maturity influence fruit ripening processes to alleviate chilling injury (CI) in mangoes (cv. Tommy Atkins). Fruit at three stages of maturity, immature (M1), half-mature (M2) and mature (M3) were stored for 18 days at 5 °C and then at 1 or 3 days at 20 °C. M1 fruit succumbed to CI after 18 days at 5 °C, with symptoms increasing in severity upon warming. Low C₂H₄ production, poor colour development, minor changes to fruit composition, insipid flavour and poor aroma revealed that fruit ripening was insufficient to reduce CI compared to M2 and M3 fruits. M2 and M3 fruits had higher C₂H₄ production rates than M1 fruit and ripened normally with acceptable flavour and aroma after 18 days at 5 °C and 3 days at 20 °C. While M3 fruit had no CI symptoms, they were overripe and fruit decay incidence was 26.6%, compared to M2 fruit which had no decay, a trace of CI symptoms and possessed the best overall quality.     

Role of surface morphology in determining the ripening behaviour of tomato (Lycopersicon esculentum Mill.) fruits

Surface characteristics of fruit mainly determine the diffusibility of gases across its boundary and also the extent to which moisture being lost from the fruit. The present study has been carried out with an objective to find out the association between the ripening related processes and surface morphology of tomato (Lycopersicon esculentum Mill.) fruit. Tomato fruits of two contrasting varieties; Pusa Gaurav (a slow ripening type) and Pusa Ruby (a relatively fast ripening type) were evaluated for physiological loss in weight (PLW), rate of respiration, effect of hypoxia on ripening, dimension of stem scar region and distribution of lenticels along with hair base cell of trichomes on the surface of the fruits. Results showed that fruits of Pusa Gaurav showed significantly lower PLW, rate of respiration, surface area of stem scar region, density of lenticels along with hair base cell of trichomes and slower ripening under hypoxia condition in comparison to Pusa Ruby. More resistance towards gaseous exchange and therefore lower O₂ to CO₂ ratio inside the fruits of Pusa Gaurav in contrast to Pusa Ruby in view of the differences in the surface morphological features in these two varieties could possibly be assigned as one of the reasons responsible for the obtained varietal difference in ripening and related changes.     

Physical and cellular structure changes of Rastali banana (Musa AAB) during growth and development

A study on the physical and physiological characteristics of Rastali bananas (Musa AAB) was carried out throughout the 12 weeks after emergence of the first hand to determine the optimum growth stage of Rastali bananas. The fruit length and diameter followed a trend similar to that observed in fruit fresh weight throughout fruit development, and three physiological stages (S1–S3) of sigmoid growth were identified. The growth rate was slow during S1 (1st to 4th week), rapid during S2 (5th to 10th week) and remained constant during S3 (11th and 12th week). Peel cells underwent periclinal growth, which was accompanied by an increase in fruit peel and pulp thickness as the fruit developed. Moreover, the pulp colour became more vivid and yellow as the fruit developed. The peel moisture content decreased while pulp moisture content increased during fruit growth and development. The pulp firmness increased from the first until seventh week, and it decreased from the seventh week until twelfth week of the experiment. Carbon dioxide (CO₂) production was the highest at S1. However, CO₂ production declined until the 10th week and remained constant at a low level of 50 mL kg⁻¹ h⁻¹ during S3. Ethylene (C₂H₄) could not be detected throughout fruit growth and development. Thus, Rastali bananas showed physiological maturity at week 11 and week 12 after emergence of the first hand with constant fruit growth.     

The effect of silver thiosulphate pre-treatment on 1-aminocyclopropane-1-carboxylic acid content and action in cut carnations

Endogenous 1-aminocyclopropane-1-carboxylic acid (ACC) levels, and the ACC → ethylene (C₂H₄) conversion of exogenously applied ACC in naturally senescing and silver thiosulphate (STS) pre-treated cut carnations, were investigated. Under natural conditions, increase in ACC accumulation coincided with the onset of the climacteric rise in C₂H₄ production. Flowers pre-treated with STS did not show this increase in ACC content. Exogenously applied ACC caused wilting within 24 h and an increase in C₂H₄ production up to 1300 nl/h/flower. Flowers successively treated with STS and ACC produced C₂H₄ at quantities much higher than the controls, but showed no wilting. Together, these data suggest that the binding of C₂H₄ to its receptor leads to an increase in the production of ACC and of C₂H₄. By blocking the C₂H₄ action, the silver ion inhibits the autocatalytic increase in C₂H₄ and the accompanying rise in ACC content.     

Effect of ethrel in aqueous solution and ethylene released from ethrel on mango fruit ripening

Summary

The effect of ethrel in aqueous solution and ethylene released from ethrel was evaluated on fruit ripening of ‘Kitchner’, ‘Dr Knight’ and ‘Abu-Samaka’ mango. Ripening was enhanced in all treated fruits of the three cultivars at all concentrations used. The ripening rate progressively increased with increase in concentration. Ethylene released from ethrel was more effective in triggering fruit ripening than dipping fruits in aqueous solution of ethrel. Depending on concentration and cultivar, ripening was 1–3.d faster in fruits dipped in 500 and 1000 ppm ethrel and 1–5.d earlier in fruits treated with 250, 500 and 1000 ppm ethylene released from ethrel, compared with untreated fruits. The effect on fruit ripening was indicated by enhanced climacteric peak, increased skin colour, increased total soluble solids and decreased flesh firmness.     

Comparative studies on the postharvest physiology of fruit from different species of Annona (custard apple)

Summary

Fruit of three Annona species, viz. cherimoya (A. cherimola Mill), sugar apple (A. squamosa L.) and custard apple (atemoya, Annona X) were ripened in ethylene-free air and under propylene. Differences were found in patterns of respiration, ethylene production and fruit firmness changes during ripening. Cherimoya and custard apple fruits showed two successive rises in respiration rate whereas sugar apple fruits showed only one. Ethylene production showed one main peak but the onset of rapid ethylene production occurred after the beginning of the respiration climacteric in all three species. Custard apple fruit had acceptable eating quality (as judged by sensory assessments and chemical analyses of pulp) for up to four days after first detectable softening, when ripened at 20°C in ethylene-free air or under propylene. Fruit ripened in ethylene-free air had better ripe fruit quality than fruit ripened under propylene.     

Improvement of internal color of oranges stored in oxygen-enriched atmospheres

‘Hamlin’, ‘Parson Brown’ and ‘Pineapple’ oranges were stored for 4 weeks at 15°C in a continuous flow of (1) air, (2) 20 mg 1^?1 ethylene (C₂H₄) in air, (3) 40% O₂ + 60% N₂, or (4) 80% O₂ + 20% N₂, followed by 2 additional weeks in air. Fruits stored in the C₂H₄ atmosphere lost rind chlorophyll faster, and the rind turned orange quicker, than fruits in the other atmospheres. However, most of the fruits stored in the C₂H₄ atmosphere had paler endocarp and juice than fruits stored in the other atmospheres. Fruits stored in 80% O₂ had the palest rind, but their endocarp and juice color were the deepest orange. Color change was detectable after 2–3 weeks and continued to develop until the end of the experiments. In 40% O₂ fruit, response was intermediate.The respiration rate of ‘Pineapple’ oranges during 4 weeks of storage in the test atmospheres was highest in the fruits stored in C₂H₄, almost as high in fruits stored in 80% O₂, and lowest in fruits kept in 40% O₂ or in air. Fruits stored in the different atmospheres did not differ significantly in total soluble solids content, total acidity, or pH of the juice, and the atmospheres did not adversely affect the flavor of the juice.     

Physicochemical changes in Mazafati date fruits incubated in hot acetic acid for accelerated ripening to prevent diseases and decay

A method was developed and optimized for the accelerated ripening of date fruits of cultivar ‘Mazafati’ to prevent diseases and decay. The date fruits were incubated in hot acetic acid solution 0.5% at 40 + 1 °C for 72 h. During the process some physicochemical changes in the fruits were studied and were found to be comparable with the changes in the fruits that naturally ripened on the tree. Fruit firmness, water insoluble solid (WIS), protein, pH, L*a*b* and E decreased during accelerated ripening whereas in control samples at 4 °C increased. Total solid (TS), total soluble solid (TSS) and acidity were slightly higher in treated fruits compared to control fruits. The greatest loss of fruit firmness occurred during the first 12 h of incubation. Organoleptic tests also showed little difference between the naturally ripened fruits on trees and accelerated ripened fruits in hot acetic acid. Overall there was no difference between the fruits and were readily acceptable to consumers.     

Respiration and ripening patterns in the life cycle of the mango fruit

Alphonso mangoes picked at any stage of maturity (starting from fruit-set) and stored at room temperature show typical respiratory changes characteristic of a fully matured mango. Fruits picked during the earlier and later stages of development show respiration climacteric within 6–10 days. During the middle stages of development the preclimacteric trough continues to extend and the climacteric occurs after 10 days. Fully mature, tree-ripe mangoes do not show a respiratory climacteric during post-harvest storage.

Chemical constituents, such as titratable acids, apparent ascorbic acid, carbohydrates and carotenoids, estimated both at harvest and in ripe fruits from different pickings show changes similar to those characteristic of a fully matured ripening fruit.

Possibilities of reducing losses from pre-harvest fruit drop and post-harvest decay by resorting to early harvesting are discussed.     

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.     

Behavior of arazá (Eugenia stipitata Mc Vaugh) fruit quality traits during growth,development and ripening

The period between fruit set and full ripening of arazá fruit grown in the Colombian Amazonia was 55 ± 5 days. Three stages of a sigmoidal growth were identified and longitudinal and equatorial traits fitted a logistic model better than three-degree polynomial models. Fruit growth clearly exhibited three different physiological stages, identified as follows: S1, involving cellular division during the first 14 days; S2, maximum fruit growth, during which cellular expansion took place (up to day 50), and a final S3 state of 5 days to reach physiological maturity. After this time, the fruit can be harvested with a dull green coloration. Parenchyma was the principal fruit tissue, and no support tissues (sclerenchyma or collenchyma) were evident. The respiratory pattern of arazá fruit was climacteric, with maximum respiration rates of around 200 mg CO₂ kg⁻¹ h⁻¹, preceded by a peak of ethylene production (20 μL C₄H₄ kg⁻¹ h⁻¹), a change in skin color from green to yellow, a total soluble solids value of 5°Brix, an increase in the sucrose and fructose content up to 2.8 μmol g⁻¹, a pH which increased to 3 units, and a decrease in titratable acidity to 400 mmol H⁺ L¹⁻. Malic acid was the main organic acid in the edible pulp and ascorbic acid was present in a concentration of 17.8 μmol g⁻¹. Skin color (as measured by hue angle) combined with titratable acidity and fruit firmness can be recommended as harvest indices for arazá fruit.     

Changes in physicochemical attributes of sweet pepper cv. Domino during fruit growth and development

The effect of harvesting sweet pepper ‘Domino’ fruit at different stages of growth and development on physicochemical attributes was studied. The suitability of fruit fresh weight, diameter and length, weeks from anthesis, total soluble solids (TSS), fruit colour change, firmness, internal CO₂ and C₂H₄ concentrations as well as fruit respiration and ethylene production as maturity indicators were evaluated. Fruits were harvested weekly until fully red ripe. Fruits took 8 weeks after anthesis (WAA) to reach harvest maturity and a further 2–3 weeks to reach full ripeness (11 WAA). Fruits exhibited a sigmoid growth pattern. Hue angle (change in colour from green to red) declined with time while chroma (colour intensity) values increased with fruit maturity, as did TSS. An increase in PⁱCO₂ and PⁱC₂H₄ accompanied the decrease in hue angle. The association between fruit ripening and the significant increase in PⁱC₂H₄ indicates that ethylene may be responsible for ripening of this cultivar of sweet pepper. Colour change and TSS were reasonable indicators of maturity of sweet pepper fruit complemented with fruit firmness.