Table olive cultivar susceptibility to impact bruising

Developing mechanical harvesting for table olives will require decreasing fruit damage during harvest and postharvest handling, transport and storage. The susceptibility to bruising and its development over time were studied in three table olive varieties, cv. ‘Manzanilla’, ‘Gordal Sevillana’ and ‘Hojiblanca’. Bruising was produced with controlled energy impacts of 56, 26, 13 mJ. A strong correlation (r² = 0.77–0.90) between bruise volume and impact energy was demonstrated. Bruise susceptibility was higher in the Manzanilla variety, followed by Hojiblanca and Gordal Sevillana cultivars. Bruise time evolution was evaluated using a spectrophotometer for visible and near infrared regions. A bruise index was developed using different wavelengths, 545, 670 and 800 nm. Most darkening due to the browning process happened within 1 h, was exponential and dependent on impact energy level. The discoloration was greatest in the Manzanilla, followed by Hojiblanca and Gordal Sevillana olives.     

Factors that affect tomato bruise development as a result of mechanical impact

External and internal factors that affect tomato bruise susceptibility such as impact- and fruit-related properties were investigated. Logistic regression was used to establish a relationship between tomato loading conditions and the resulting damage. Impact-specific models were built for a more precise determination of the bruise risk related to a narrow range of impact energies, being low (23 mJ), medium (71 mJ), high (158 mJ) and very high (216 mJ) impacts.Pericarp tissue over the locules was much more sensitive to bruise development than radial wall tissue. Tomatoes at room temperature (20 °C) were more sensitive than fruit stored at 12 °C. Tomato susceptibility to bruising increased substantially with ripening and loading conditions. The duration of the impact played a critical role in the bruise development and it is largely determined by fruit intrinsic parameters. Additional effects of the restitution coefficient and the fruit mass were found. Finally, different factors are responsible for tomato bruising in the various impact classes. The effect of low and medium energy impacts is largely controlled by the fruit texture. Especially medium impacts seem to substantially increase the bruise potential. The bruise potential of high and very high impacts mainly depends on fruit ripeness and the location of impact.     

Temperature effects on peel spotting in ‘Sucrier’ banana fruit

Banana fruit of the cultivar ‘Sucrier’ (Musa acuminata, AA Group) develops peel spotting at a relatively early stage of development (when the peel is about as slightly more yellow than green). Holding ripening bananas at 15 and 18 °C instead of room temperature (26–27 °C) only temporarily reduced spotting, but holding the fruit at 12 °C completely prevented it. The 12 °C treatment resulted in a lower level of total free phenolics, but had no effect on PAL or PPO activity. Transfer of banana fruit previously held at 12 °C to room temperature rapidly increased peel spotting. Transfer of bananas that had some spotting, from room temperature to 12 °C did not prevent further development of the spotting. It is concluded that holding spotless fruit at 12 °C prevents the spotting, although only if they are kept at that temperature, and that PAL and PPO activities seem not rate-limiting.     

Influence of environmental conditions on the quality attributes and shelf life of ‘Goldfinger’ bananas

‘Goldfinger’ bananas (Musa accuminata, FHIA-01) were harvested, held for 14–22 d at five temperatures and a constant relative humidity (RH) or at five RHs and a constant temperature and evaluated for quality attributes. The objectives of this work were to: (1) create quality curves for bananas stored at chilling and non-chilling temperatures; (2) create quality curves for bananas stored at a non-chilling temperatures and different RHs; (3) identify which sensory quality attribute limits the shelf life and marketability of bananas when stored at chilling and non-chilling temperatures or at different RHs; and (4) correlate subjective sensory attributes with quantitative quality measurements. Results from this study showed that temperature had a more significant impact on the quality of banana than RH. Bananas stored at temperatures higher than 10 °C were yellower and softer but had lower starch and higher soluble solids and total sugar content than those stored at lower temperatures. When stored at 2, 5 and 10 °C, bananas developed chilling injury (CI) and abnormal ripening when transferred to 20 °C. The most remarkable impact of RH on banana quality was on weight loss, which was significantly higher in fruit held below 80% RH than in fruit held in 87 or 92% RH. CI was the first sensory quality attribute to reach the limit of acceptability in fruit stored at 2, 5 and 10 °C, whereas color changes and softening limited the shelf life of bananas stored at 15 and 20 °C. Changes in color and/or softening were the two main sensory attributes that limited the shelf life of bananas stored at different RHs. Overall, for maximum quality and shelf life bananas should be stored at or above 15 °C and 92% RH. Finally, sensory attributes can be used to estimate peel color, pulp softening and sweetness, while SSC can be used as a reliable and simple method to estimate the total sugar content of bananas stored at different temperatures or different RHs.     

Effect of oxalic acid on ripening attributes of banana fruit during storage

The effect of exogenous oxalic acid treatment on ripening attributes of banana fruit during storage was investigated. Banana fruit were dipped into solutions of 0 (control) or 20 mM oxalic acid for 10 min and then stored at room temperature (23 ± 2 °C) and 75–90% relative humidity. The application of oxalic acid reduced fruit deterioration during storage. The oxalic acid treatment also reduced the rates of respiration and ethylene production, and delayed the decreases in firmness, hue angle, and maximal chlorophyll fluorescence (Fv/Fm) of banana fruit during storage. Furthermore, fruit treated with oxalic acid exhibited higher superoxide dismutase activity and antioxidant capability with a lower production of reactive oxygen species at the late storage period compared with non-oxalic acid-treated fruit. Overall, the oxalic acid treatment was effective in inhibiting postharvest ripening of banana fruit and exhibited the potential for commercial application to store the bananas at room temperature. It can be concluded that the delay in banana fruit ripening associated with oxalic acid treatment could be due to inhibition of respiration and ethylene production rates, and reduction of oxidative injury caused by reactive oxygen species through increased antioxidant activity.     

The effect of dialkylamine compounds and related derivatives of 1-methylcyclopropene in counteracting ethylene responses in banana fruit

Compounds that can block the ethylene receptor and be applied either as a gas or as a salt by spray or dip have been prepared and tested. Cyclopropenes with a methyl group in the 1-position, on which was attached a substituted amine, were allowed to evaporate in the presence of bananas that were treated with the gas. The minimum amount of a given compound required to inhibit chlorophyll degradation in the banana peel (an indicator of protective effect of the compound against ethylene action) that was subsequently exposed to ethylene, varied considerably depending on the compound, but N,N-dipropyl-(1-cyclopropenylmethyl)amine and N,N-di-(1-cyclopropenylmethyl)amine were the most effective. The degree of response to the ethylene inhibitory effect was similar for all of the compounds tested (32–34 d). The amount of cyclopropene compound required for inhibiting ethylene action following a 24 h exposure of bananas to the salt followed by a 15 h exposure to ethylene was higher than that required by the gas form used under the same conditions for the same effect. However, time of exposure could be much longer than 24 h with the salt than with the gas. The bananas treated with the salt do not need to be in an air-tight container, but could be used in open spaces. Only the banana peel appeared to be protected against ethylene during the 24 h interval when the salt was used. The pulp ripened upon exposure to ethylene.     

Effect of ethylene degreening on the development of postharvest penicillium molds and fruit quality of early season citrus fruit

The effect of commercial degreening with ethylene gas on fruit susceptibility and quality and development of postharvest green (GM) and blue (BM) molds on early season citrus fruit was investigated. Each cultivar was harvested with different peel color indexes (CI). Fruit were exposed for 3 d to 2 μL L⁻¹ ethylene at 21 °C and 95–100% RH before or after artificial inoculation with Penicillium digitatum or Penicillium italicum. Control fruit were kept at the same environmental conditions without ethylene. Fruit were stored at either 20 °C for 7 d or 5 °C for 14 d and disease incidence (%) and severity (lesion diameter) were assessed. No significant effect of commercial degreening was observed on fruit susceptibility to both GM and BM on citrus cultivars inoculated after degreening. Likewise, no significant effect was observed on disease incidence on citrus cultivars inoculated before degreening and stored at either 20 °C for 7 d or 5 °C for 14 d. In contrast, in cultivars like ‘Clemenules’ mandarins and ‘Navelina’ oranges, degreening significantly increased the severity on fruit with higher initial CI (−3.6 and 1.7, respectively). GM and BM severity on degreened and control ‘Clemenules’ mandarins incubated at 20 °C for 7 d was 146 and 118 mm and 56 and 46 mm, respectively. In general, commercial degreening did not significantly affect external and internal quality attributes of citrus cultivars. Commercial degreening after inoculation of less green (more mature) fruit showed a trend to increase mold severity, presumably through an aging effect (acceleration of peel senescence).     

Physiology and quality response of harvested banana fruit to cold shock

Experiments were conducted to examine softening and quality responses of harvested banana fruit to cold shock treatment intended to extend shelf-life. Fruit were immersed in ice-water for 1 h, then treated with or without 100 μL L^?1 ethylene for 24 h at 24 °C, and finally stored at 20 °C. Fruit firmness, chlorophyll content, ethylene production, respiration rates, contents of pectin, starch and sugar, and the activities of the cell wall modifying enzymes polygalacturonase (PG), pectin methylesterase (PME) and CMCase (cellulase, endo-1,4-β-glucanase) were analyzed. Total amylase activity was also measured. Immersion in ice-water for 1 h effectively inhibited ripening-associated processes, including peel de-greening and pulp softening during storage or ripening. The delay in ripening was also manifest in reduced ethylene production and respiration rates. The inhibition of softening by cold shock treatment was related to decreased PG and PME activities, that is, retardation of pectin solubilization/degradation. Reduced activities of CMCase and total amylase and conversion of starch to sugar by ice-water immersion also contributed to the delay in softening of harvested banana fruit.     

High oxygen levels promote peel spotting in banana fruit

We studied the effect of high oxygen on early peel spotting in ‘Sucrier’ bananas held at 25 °C and 90% RH. Fruit first ripened to colour index 3–4 (about as yellow as green) and were then held in containers with a continuous gas flow of 18 ± 2 kPa (control) or 90 ± 2 kPa oxygen. High oxygen promoted peel spotting. The in vitro activities of phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO), measured both in the whole peel and in peel spots, were lower in high oxygen than in the controls. The level of total free phenolics, both in the whole peel and in peel spots, was lower in the high oxygen treatment. Dopamine content in the peel spots decreased rapidly, earlier in the high oxygen treatments than in controls. It is concluded that peel spotting was not correlated with in vitro PAL and PPO activities. Decrease in dopamine levels correlated with peel spotting, indicating that it might be used as a substrate for the browning reaction.     

Effects of cinnamon extract,chitosan coating,hot water treatment and their combinations on crown rot disease and quality of banana fruit

The antifungal activities of cinnamon extract (CE), piper extract (PE) and garlic extract (GE) were evaluated on banana crown rot fungi (Colletotrichum musae, Fusarium spp. and Lasiodiplodia theobromae) in vitro. The assay was conducted with extracts of CE, PE and GE with concentrations of 0, 0.1, 0.5, 1.0, 5.0, 10.0 and 0.75 g L⁻¹ of carbendazim (CBZ) on potato dextrose agar at room temperature. CE completely inhibited conidial germination and mycelial growth of all fungi at 5.0 g L⁻¹. PE totally suppressed mycelial growth of all fungi at 5.0 g L⁻¹ and conidial germination at 10.0 g L⁻¹ except for Fusarium spp. GE had no significant effects but low concentrations (0.1 and 0.5 g L⁻¹) enhanced germ tube elongation of the three fungi. The ED₅₀ values were higher for mycelial growth than for conidia except for Fusarium spp. Combined treatments were investigated on crown rot development in banana fruit (Musa AAA group ‘Kluai Hom thong’). Treatments included 5.0 g L⁻¹ CE, 1% (w/v) chitosan solution, hot water treatment (HWT, 45 °C for 20 min), CE plus chitosan, CE plus HWT and 0.75 g L⁻¹ of CBZ, applied before and after inoculation of the fruit. Crown rot development was assessed during storage at 13 °C for 7 weeks. Disease development was least (25%) on CE treated fruit after inoculation compared to CBZ but was higher when CE was applied before inoculation. Chitosan significantly delayed ripening as in terms of peel color, firmness, soluble solids and disease severity. CE showed no negative effects on quality of fruit. CE plus HWT caused unacceptable peel browning.     

Effect of gamma irradiation on the physico-chemical and visual properties of mango (Mangifera indica L.), cv. ‘Dushehri’ and ‘Fazli’ stored at 20 °C

The effect of γ-irradiation doses (0.3, 0.5, 0.7, 1.0, 6.0, 10.0 kGy) on different physico-chemical and visual properties of two Indian cultivars of mango, cv. ‘Dushehri’ and ‘Fazli’ was observed during storage at 20 °C for the evaluation of delayed ripening and extension of shelf-life. Visually all the irradiated fruit showed greener peel and lighter pulp throughout the storage, however, radiation injuries were present in ‘Dushehri’ treated with 6–10 kGy and in ‘Fazli’ with 1–10 kGy. Loss of fruit due to rotting was less in the irradiated samples, treated up to 1 kGy of both the cultivars. Irradiated fruit of both the cultivars at high doses (6–10 kGy) showed increased sugar content from 0 d, however, all the treated fruit registered a slower rate of increase of sugars with storage compared to the respective controls and those treated with the lower doses of 0.5 and 0.7 kGy attained peak sugar concentration later. Significant (p ≤ 0.05) textural deterioration could be detected immediately after irradiation, in ‘Dushehri’ at doses ≥1 kGy and in ‘Fazli’ at doses ≥0.7 kGy. However, low dose treated fruit (0.3–1 kGy) of both the cultivars softened at a considerably slower rate during storage and registered significantly greater fruit firmness (compression strength) throughout the storage period. Similarly, ‘Dushehri’ treated with 0.3–0.7 kGy and Fazli treated with 0.7 kGy registered significantly greater flesh firmness (shear strength). ‘Dushehri’ treated with 0.3–1 kGy and ‘Fazli’ with 0.5–1 kGy also registered significantly harder and tougher peel, as determined by puncture test, throughout the storage. Scanning electron microscopy (SEM) performed on 3rd and 2nd d of storage of ‘Dushehri’ and ‘Fazli’ respectively, revealed microstructural breakdown at and above 1 kGy in both cultivars. Cell separation could be observed in ‘Fazli’ even at 0.7 kGy. SEM also revealed that the control fruit were in a more advanced stage of ripening than the low dose treated fruit. The study showed the feasibility of low dose γ-irradiation on ‘Dushehri’ (0.3–0.7 kGy) and ‘Fazli’ (0.5 and 0.7 kGy) that induced useful delay in ripening and extension of shelf-life by a minimum of 3 and 4 d, respectively.     

Reduction of energy usage during storage and transport of bananas by management of exogenous ethylene levels

Unripe Australian-grown Cavendish and Lady Finger bananas were stored at 15, 20 and 25 °C in an atmosphere containing 0.001, 0.01, 0.1 and 1.0 μL/L ethylene in air and the green life was determined as the time to reach the respiratory climacteric. As expected, green life increased as the temperature and ethylene concentration decreased. The equation describing the relationship between temperature, ethylene concentration and green life of Cavendish bananas was applied to a five-day 3000 km road transport route from the major tropical production area to the major urban markets. It predicted that bananas transported in the prevailing mean summer temperature of 25 °C would not require refrigeration if the ethylene level did not exceed 0.58 μL/L while transport at the mean winter temperature of 14 °C fruit could withstand a level of about 0.90 μL/L without ripening en route. The equation was also applied to a shipment protocol of 19 days for bananas exported from Central America to southern Europe. This predicted that fruit could be transported without refrigeration if ethylene levels were maintained at 0.04 μL/L during the winter temperature of 17 °C and at 0.002 μL/L at the summer transport temperature of 24 °C. Since a range of technologies are available to maintain such low ethylene levels or reduce the action of ethylene, these findings suggest that the current refrigerated transport of bananas could be minimised or eliminated. The use of higher temperatures in the supply chain would reduce energy consumption with resultant environmental and economic benefits.     

A novel technique using 1-MCP microbubbles for delaying postharvest ripening of banana fruit

This study aimed to investigate the application of microbubble technology for delaying banana ripening. A preparation of 1-MCP designed for use as a form of aqueous micro bubble (MBs) solutions was formulated. Banana fruit were immersed in 500 nL L⁻¹ of aqueous 1-MCP microbubbles (1-MCP-MBs) or fumigated with 500 nL L⁻¹ 1-MCP, then stored at 25 °C for 8 days. 1-MCP-MBs were more effective in delaying postharvest ripening than conventional 1-MCP fumigation. 1-MCP-MBs reduced the respiration rate and ethylene production compared to the control and 1-MCP fumigated fruit. Moreover, 1-MCP-MBs delayed yellowing and maintained firmness of banana fruit during storage. These results indicate that 1-MCP-MBs can be used as an alternative method for delaying the postharvest ripening of banana fruit, and its application for other commodities needs to be further elucidated.     

Chilling injury in mango (Mangifera indica) fruit peel: Relationship with ascorbic acid concentrations and antioxidant enzyme activities

We investigated the degree of chilling injury (CI) in mango (Mangifera indica) fruit stored at 4 °C or 12 °C, in relation to peel ascorbic acid concentrations, total antioxidant capacity, and the activities of four antioxidative enzymes. In cv. Nam Dok Mai fruit exposed to 4 °C, CI (peel browning) was found after 5 days, whilst CI in cv. Choke Anan fruit started after 10 days and did not reach the same degree. When held at 27–28 °C, following various periods of exposure to 4 °C, peel browning in both cultivars increased, but that in cv. Nam Dok Mai remained higher than in cv. Choke Anan. An inverse correlation was found between peel browning and ascorbic acid concentrations, and between peel browning and total antioxidant capacity, measured using the FRAP method. In cv. Nam Dok Mai, the superoxide dismutase (SOD) and catalase (CAT) activities were lower during storage at 4 °C than during storage at 12 °C, while such a difference was not found in cv. Choke Anan. When compared to cv. Choke Anan, lower activities of ascorbate peroxidase (APX) and of guaiacol peroxidase (POX) were found in the peel of cv. Nam Dok Mai. However, no difference was observed in APX and in POX activities in the peel of cv. Nam Dok Mai stored at 4 °C or 12 °C. This means that the relationships between CI and APX and POX activities were weak.     

Residual effects of low oxygen storage of mature green fruit on ripening processes and ester biosynthesis during ripening in bananas

Mature green banana (Musa sapientum L. cv. Cavendish) fruit were stored in 0.5%, 2%, or 21% O₂ for 7 days at 20 °C before ripening was initiated by ethylene. Residual effects of low O₂ storage in mature green fruit on ripening and ester biosynthesis in fruit were investigated during ripening for up to 6 d at 20 °C. Concentrations of ethanol in mature green fruit did not change during storage in both 21% and 2% O₂ atmospheres, but increased in fruit stored in 0.5% O₂. The activities of alcohol dehydrogenase (ADH) in 2% and 21% O₂ atmospheres remained very low throughout the storage period, but significantly increased with 0.5% O₂. After transferring fruit to regular air and trigging ripening with ethylene, yellowing of peel, fruit softening and hydrolysis of starch in fruit stored in low O₂ atmospheres were slower than in the control. Fruit stored in low O₂ also showed a delayed onset of the climacteric peak. The activities of ADH were lower in the low O₂ stored fruit than in the control fruit. Productions of ethyl acetate, isoamyl acetate, and isobutyl acetate were remarkably suppressed by low O₂ storage. Alcohol acetyltransferase activity increased gradually with storage time in all treatments, being significantly lower in fruit with low O₂ pretreatments. The results indicate that low O₂ plus room temperature storage can extend storage life of bananas with the sacrifice of a low production of ester volatiles.     

Induction of ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ Pears by temperature and ethylene conditioning

Methods were tested for rapid induction of ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ pears in order to facilitate early marketing. Fruit of each cultivar were harvested at the onset of maturity and conditioned to develop ripening capacity by exposure to 100 μL L⁻¹ ethylene at 20 °C for 0, 24, 48, or 72 h, followed by varying durations of temperature conditioning at −0.5 or 10 °C. Ripening capacity was tested by measuring fruit firmness after 7 d at 20 °C after completion of conditioning treatments. Fruit firmness was also measured after conditioning but before ripening, and was designated “shipping firmness,” indicative of the potential for the fruit to withstand transport conditions without physical injury. With temperature conditioning at −0.5 °C only, ‘Packham's Triumph’ pears needed 45 d to develop ripening capacity, while ‘Gebhard Red D’Anjou’ pears were not capable of fully ripening after 60 d, the longest duration tested. Using ethylene only, 72 h exposure was necessary to develop full ripening capacity in both cultivars, and adequate shipping firmness was maintained. Using temperature conditioning at 10 °C, ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ developed within 10 and 20 d, respectively, but shipping firmness in ‘Gebhard Red D’Anjou’ was compromised at 20 d. In both cultivars, 24 or 48 h in ethylene followed by 5 d at 10 °C induced ripening capacity while maintaining adequate shipping firmness.     

Effect of atmospheric modification, 1-MCP and chemicals on quality of fresh-cut banana

Fresh-cut banana slices have a short shelf-life due to fast browning and softening after processing. The effects of atmospheric modification, exposure to 1-MCP, and chemical dips on the quality of fresh-cut bananas were determined. Low levels of O₂ (2 and 4 kPa) and high levels of CO₂ (5 and 10 kPa), alone or in combination, did not prevent browning and softening of fresh-cut banana slices. Softening and respiration rates were decreased in response to 1-MCP treatment (1 μL L⁻¹ for 6 h at 14 °C) of fresh-cut banana slices (after processing), but their ethylene production and browning rates were not influenced. A 2-min dip in a mixture of 1% (w/v) CaCl₂ + 1% (w/v) ascorbic acid + 0.5% (w/v) cysteine effectively prevented browning and softening of the slices for 6 days at 5 °C. Dips in less than 0.5% cysteine promoted pinking of fresh-cut banana slices, while concentrations between 0.5 and 1.0% cysteine delayed browning and softening and extended the post-cutting life to 7 days at 5 °C.     

The effect of drop height on bruising of selected apple varieties

This paper presents an analysis of fruit impact in time and the results of the relationships between the bruise size and various impact parameters. The measuring device allows simultaneously analysis of the three basic quantities: impact velocity, rebound velocity and force response in time, and testing the momentum conservation law for a body such as an apple. In the experiments, the impact velocity 0.25 m s⁻¹ was the maximum velocity at which bruises for all tested apple varieties did not develop. The parameters which were the most strongly correlated with apple bruise volume were maximum force response and dissipated energy, which can be used to predict direct impact effects.     

Effects of postharvest treatments on gene expression in Prunus persica fruit: Normal and altered ripening

Peach (Prunus persica) fruit have a short shelf-life, and the most common method employed to delay ripening and increase their postharvest life is cold storage. However, after extended storage at low temperature some cultivars have alterated ripening processes, resulting in a lack of juice and a woolly texture. To improve our understanding of the molecular mechanisms involved in the responses of peach fruit to cold storage we determined gene expression changes of fruit (cv. O’Henry) under different postharvest conditions: ripening (5 days at 21 °C), cold storage (21 days at 4 °C) and induction of woolliness (21 days at 4 °C followed by 5 days at 21 °C).Cluster analyses of genes differentially expressed between treatments revealed unique patterns associated with biological processes that operate during postharvest treatments. Genes up-regulated during postharvest ripening and woolliness include components of ethylene, and aroma biosynthesis as well as oxidative stress response. During cold storage treatment and woolliness, several genes linked to the oxidative stress response increased in abundance, suggesting changes in redox status. Quantitative RT-PCR analysis showed a sequential increase levels of mRNAs encoding key components of cellular stress response. Moreover, after 21 days of cold storage, expression of genes encoding oxidoreductase, catalase, superoxide dismutase and gluthatione reductase was still significantly higher than before cold treatment, suggesting that fruit cells were able to respond to the increased production of ROS that was induced by extended cold storage. In the woolly fruit, up-regulation of stress response genes was accompanied by down-regulation of key components of metabolic pathways that are active during peach ripening. The altered expression pattern of these genes might account for the abnormal ripening of woolly fruit.