Bruise susceptibility of banana peel in relation to genotype and post-climacteric storage conditions

The aim of this study was to understand the genotypic factors and post-climacteric storage conditions that affect bruise susceptibility of banana peel. Putative physicochemical indicators of bruise susceptibility, including peel electrolyte leakage (PEL), total polyphenolic content, hardness, water content, and peel thickness, were investigated. Bruise susceptibility is the lowest impact energy needed to produce visible bruising by an object dropped on post-climacteric banana fruit from a pre-determined height, converted into impact energy (20–200 mJ with a 20 mJ increment). The bananas were stored either at 18 °C throughout ripening or at 13 °C between the 2nd and 6th day after ethylene induction. Five cultivars with contrasting susceptibility to impact bruises were used. Neither Grande Naine nor hybrid Flhorban925 bruised at the maximum impact energy (200 mJ) during ripening whatever the storage conditions. A gradient in bruise susceptibility was observed among the other cultivars: French Corne > Fougamou > hybrid Flhorban916. Bruise susceptibility increased during ripening and was higher in bananas stored at 18 °C. The lower ripening temperature resulted in a two-day delay to fruit maturity as well as in bruise susceptibility. Bruise susceptibility was positively correlated with PEL (R = 0.78) and to a lesser extent negatively correlated with hardness (R = −0.45), and was not correlated with polyphenolic content. In conclusion, membrane permeability provides the first clue to understanding bruise susceptibility.     

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.     

Bruise susceptibilities of ‘Gala’ apples as affected by orchard management practices and harvest date

This study evaluated the influences of irrigation (frequent versus none), crop load (high versus low), and nitrogen (urea fertilizer versus none) on bruise sensitivity of mature apple fruit (cv. Gala) picked on three harvest dates. It includes a proposal for a new index of bruise sensitivity, called specific bruise susceptibility, as an additional tool for studying the effects of management practices on bruising of fresh produce. Results obtained showed that reducing irrigation frequency and practising selective and timely picking of mature fruit offer some potential to reduce fruit susceptibility to bruising. Analyses of the effects of orchard management practices based on specific bruise susceptibility of fruit (mm³ J⁻¹ g⁻¹) suggested that other biophysical fruit properties such as curvature (shape) and maturity status (rather than size alone) may have greater influence on the way in which induced variations in fruit size (e.g. through crop loading and irrigation) respond to mechanical loads during impact bruising.     

Supervised classification of bruised apples with respect to the time after bruising on the basis of hyperspectral imaging data

Apple bruising, as a mechanical damage, occurs due to impact, compression, vibration or abrasion during handling. However, the symptoms of this damage, browning and softening of the tissue, appear not immediately but after a certain period of time after bruising. For sorting and grading systems, the information about how long the bruise exists in affected fruit can be valuable. VNIR (visible and near-infrared) and SWIR (short wavelength infrared) spectral characteristics of sound and bruised apple tissues were analyzed during a two week period after bruising. Supervised classification methods, including support vector machines, linear logistic regression, neural networks and decision trees, were used and compared to check their effectiveness for distinguishing time after bruising with respect to five varieties of apples. The detection system included hyperspectral cameras equipped with sensors working in the visible and near-infrared (400–1000 nm) and short wavelength infrared (1000–2500 nm) ranges. The results of supervised classification revealed good applicability of hyperspectral imaging in VNIR and SWIR spectral ranges for detecting the number of days after bruising. The linear logistic regression neural networks models were found to be the best classifiers in the majority of models developed. Prediction accuracies higher than 90% were obtained for classification models on spectral data pretreated with the second derivative.     

Magnetic resonance imaging provides spatial resolution of Chilling Injury in Micro-Tom tomato (Solanum lycopersicum L.) fruit

Magnetic resonance imaging (MRI) was used to monitor internal changes in harvested tomato (Solanum lycopersicum L. cv. Micro-Tom) fruit. Measurements of ethylene evolution, respiration, and ion leakage indicated that the fruit developed chilling injury (CI) after storage at 0 °C. Unlike these measurements, MRI provided spatially resolved data. The apparent diffusion coefficient (ADC), which is an indication of water mobility in tissues, was calculated from MRIs of the different parts of the fruit. Storage for 1 or 2 weeks at 0 °C caused no difference in the ADCs (D-values) in the pericarp, but it did lead to higher values in the inner tissues i.e., the columella and locular region compared to non-chilled fruit (P < 0.05). Changes in inner fruit D-values after 1 and 2 weeks of chilling at 0 °C were similar to changes in respiration, ethylene production and ion leakage which increased (P < 0.05) compared to the non-chilled controls. Most CI studies of tomato fruit used pericarp tissue. Our data indicate that columella tissue changes occur in response to chilling injury in tomato fruit and suggest that more caution is needed when interpreting data from experiments commonly used to study this phenomenon.     

Interpreting textural changes in low temperature stored tomatoes

Low temperature storage alters tomato textural properties, resulting in unusual changes in firmness, while ripening during cool storage can confound these chilling-induced textural changes. Inconsistent results have been reported related to chilling-induced alteration in tomato texture. The effects of chilling on tomato texture were investigated using fruit stored at 2.5 or 6 °C (chilled) or 20 °C (non-chilled) for 27 d before transfer to 20 °C. Given that many factors influence the firmness of chilling-injured tomato and different measurement methods indicate different characteristics of tomato texture, the present study employed a range of textural measurement techniques in order to interpret chilling-induced textural changes in tomatoes during long term storage. Analysis of data from a range of textural methods indicated that storage at 6 °C mainly induced loss of turgor whereas 2.5 °C induced loss of tissue integrity along with turgor loss. Plotting textural changes against colour as an indicator of ripening allowed a clearer definition of chilling-induced textural change.     

Diffusivity of 1-methylcyclopropene in spinach and bok choi leaf tissue,disks of tomato and avocado fruit tissue,and whole tomato fruit

Gaseous 1-methylcyclopropene (1-MCP) has been widely employed for delaying ripening and senescence of harvested fruit and vegetables; however, details on ingress of gaseous1-MCP in plant tissues, which might contribute to differences in responsiveness of different horticultural commodities to 1-MCP, have not been reported. In this study, we used spinach and bok choi leaves, disks from tomato epidermis, stem-scar and avocado-exocarp tissues, and whole tomato fruit to examine ingress of gaseous 1-MCP. Using a dual-flask system, equilibration of 20 μL L⁻¹ (831 μmol m⁻³) 1-MCP through leaf tissue was reached within 1–2 h, and paralleled 1-MCP transfer through glass-fiber filter paper. For disks derived from fruit tissues, changes in 1-MCP concentrations in the dual-flask system showed anomalous patterns, declining as much as 70% in source flasks with negligible accumulation in sink flasks. The pattern of 1-MCP distribution was markedly different from that of ethylene, which approached equal distribution with tomato stem-scar and avocado exocarp but not tomato epidermis tissues. 1-MCP ingress was further addressed by exposing whole tomato fruit to 20 μL L⁻¹ 1-MCP followed by sampling of internal fruit atmosphere. Tomato fruit accumulated internal gaseous 1-MCP rapidly, reaching approximately 8–9 μL L⁻¹ within 3–6 h at 20 °C. Internal 1-MCP concentration ([1-MCP]) declined around 74 and 94% at 1 and 3 h after exposure, respectively. Ingress was similar at all ripening stages and reduced by 45% in fruit coated with commercial wax. Blocking 1-MCP ingress through stem- and blossom-scar tissues reduced accumulation by around 60%, indicating that ingress also occurs through epidermal tissue. Fruit preloaded with 1-MCP and immersed in water for 2 h retained about 45% of post-exposure gaseous [1-MCP], indicating that 1-MCP is not rapidly sorbed or metabolized by whole tomato fruit. Rapid ingress of gaseous 1-MCP was also observed in tomato fruit exposed to aqueous 1-MCP. Both accumulation and post-exposure decline in internal gaseous [1-MCP] are likely to vary among different fruit and vegetables in accordance with inherent sorption-capacity, surface properties (e.g., waxes, stoma), volume and continuity of gas-filled intercellular spaces, and tissue hydration.     

Effect of hyperbaric pressure and temperature on respiration rates and quality attributes of tomato

Previous work with hyperbaric treatment of tomato focused on application at lower temperature (13 °C). In this work, hyperbaric treatment at varying pressure levels (i.e., 0.1, 0.3, 0.5, 0.7 and 0.9 MPa) at ambient temperature (20 °C) was tested as a potential alternative to conventional refrigerated storage (0.1 MPa at 13 °C) to preserve tomato quality. The experiments were divided into 3 phases: (1) 4 day of hyperbaric treatment, (2) 5 day of post-treatment ripening, and (3) 10 day of post-treatment ripening. Respiration rate (RR) of the tomatoes was continuously monitored during the course of the hyperbaric treatments. Quality attributes were assessed immediately after removal from the hyperbaric treatments and after 5 and 10 day ripening at 20 °C after removal from the treatments. Hyperbaric treatments at ≥0.3 MPa resulted in RR equal or higher than the RR in control fruit (0.1 MPa at 20 °C). The lowest RR was obtained from tomato stored at 0.1 MPa at 13 °C. Hyperbaric treatment at 0.5, 0.7 and 0.9 MPa significantly reduced weight loss, retained color, firmness, total soluble solid (TSS), titratable acidity (TA) and TSS:TA ratio at similar levels as the tomato treated at 13 °C and 0.1 MPa. Firmness after treatment was highest for fruit from 0.1 MPa at 13 °C and from 0.5, 0.7 and 0.9 MPa at 20 °C. The higher firmness advantage declined by 5 day of ripening after treatment, with higher firmness only being retained for fruit from the 0.9 MPa at 20 °C and the 0.1 MPa at 13 °C treatments. After 10 day ripening, firmness was similar for all treatments. Lightness (L*) and hue angle were greater for all treatments compared with the 0.1 MPa at 20 °C treatment. However, only the greater hue angle difference was maintained after 5 day of ripening. After 10 day ripening, no significant differences were found in color attributes. Only 0.1 MPa at 13 °C retained higher soluble solids, lower titratable acidity and higher TSS:TA ratios after treatment and after 5 day ripening. At 10 day of ripening none of the quality attribute differences noted were retained for any of the treatments. These results show that the only consistent effect of hyperbaric treatment at 0.5, 0.7 and 0.9 MPa was to reduce weight loss and enhance firmness retention up to 5 day ripening after treatment.     

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.     

Modeling the effect of preharvest weather conditions on the incidence of soft scald in ‘Honeycrisp’ apples

‘Honeycrisp’ apples show a high susceptibility to physiological disorders such as soft scald. The objective of this study was to identify weather parameters during fruit development that influence soft scald development in ‘Honeycrisp’ apples. Soft scald susceptibility of ‘Honeycrisp’ has been linked to weather conditions during specific periods of the growing season, referenced by given phenological stages. Using weather data and fruit quality analysis data from three sites in Ontario, two sites in Quebec and one site in Nova Scotia for three seasons (2009–2011) and four additional sites in Ontario from 2002–2006, a model for soft scald incidence (SSI) was built to predict the susceptibility of ‘Honeycrisp’ apples prior to storage. This model used primarily two weather variables during three sub-periods of fruit development to accumulate a SSI index (%) during the growing season, from full bloom to harvest time. Relatively wet conditions during phenological stages from full bloom until 10 mm diameter (precipitation > 0.5 mm) and from 10 mm until 50% of final caliber (precipitation > 6.0 mm), cool conditions (temperature < 15 °C) from full bloom until 10 mm diameter, and warm conditions (temperature > 20 °C) from 50 to 80% of final size are conditions that resulted in increased soft scald susceptibility for ‘Honeycrisp’ apples. The SSI model may be used by producers to establish more appropriate marketing and storage strategies depending on levels of susceptibility to soft scald development predicted prior to storage.     

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).     

Pulsed light effects on surface decontamination,physical qualities and nutritional composition of tomato fruit

Pulsed light (PL) is a nonthermal food technology with a potential as postharvest decontamination strategy for fruit and vegetables. The feasibility of PL in extending shelf-life of food products while assuring appropriate quality is still under investigation. The effect of pulsed light (PL) on surface decontamination (natural and inoculated microorganisms), physical (colour, texture and weight) and nutritional quality (ascorbic acid and major carotenoids) was investigated in red-ripe tomatoes during 15 days of storage at 20 °C. The application of PL treatments at fluences of 2.68 and 5.36 J/cm² reduced microbial loads during storage of whole tomatoes. One log₁₀ reduction on the microflora present in both skin and peduncle scar parts of the tomato was obtained with a fluence of 4 J/cm². Fluences of 2.2 J/cm² allowed a 2.3 log₁₀ reduction of Saccharomyces cerevisiae inoculated onto the tomato surface. Softening, increased loss of weight, and wrinkles on the tomato surface appeared after 3 days on PL treated tomato fruit. Ascorbic acid levels remained unchanged during storage. Total lycopene, α-carotene and β-carotene contents and lycopene isomerisation percent were higher in tomato extracts prepared with fresh tomato fruit treated with a high PL dose of 30 J/cm². An increase in the bio-accessibility of lycopene was observed in hot-break purees prepared with fresh tomatoes treated at 5.36 J/cm² and stored 15 days. In conclusion, PL treatment of fresh tomato would result in a reduction in microbiological contaminants without compromising the nutritional value; but it did induce some appearance defects.     

Efficacy of 1-MCP treatment in tomato fruit: 1. Duration and concentration of 1-MCP treatment to gain an effective delay of postharvest ripening

‘Raf’ tomato fruit were harvested at the mature-green stage and treated with 1-methylcyclopropene (1-MCP) at 0.5 (for 3, 6, 12 or 24 h) or 1 μl l⁻¹ for 3 or 6 h. Fruit were stored at 10 °C for 7 days and a further 4 days at 20 °C for a shelf life period. All 1-MCP treatments reduced both ethylene production and respiration rate and in turn retarded the changes in parameters related to fruit ripening, such as fruit softening, colour (a^*) change, and increase in ripening index (TSS/TA ratio). These effects were significantly higher when 1-MCP was applied at 0.5 μl l⁻¹ for 24 h. In order to obtain the maximum benefit from 1-MCP, this treatment would be the most suitable for commercial purposes.     

High-pressure water washing and continuous high humidity during storage and shelf conditions prolongs quality of red capsicums (Capsicum annuum L.)

In order to develop practical sea freight and marketing options for high quality red capsicums, we have investigated washing treatments that can minimize deterioration when fruit are subsequently stored under high humidity packaging conditions, at cool (6–8 °C) and warm (20 °C) temperatures. In small-scale trials using vented plastic bags to provide high humidity, fruit washed with unheated high-pressure water (517 kPa) had reduced incidence of flesh rots and deterioration of the calyx and stem compared to controls (unwashed or passed through a commercial packing line) or hot water drenched fruit (55 °C for 30 s) following a high humidity storage regime of 2 weeks at 6–8 °C and a further 14 d at 20 °C. In a more extensive trial where 5 kg boxes of fruit were used as replicates, washing with high-pressure water, packing in unperforated plastic box-liners and storing at 6–8 °C for 2 weeks, then 21 d at 20 °C resulted in 84% acceptability. In contrast, acceptability of fruit treated in a commercial packing line stored under regular (uncontrolled humidity) conditions or inside box liners (high relative humidity) declined rapidly at 20 °C after 2 weeks cool storage, with final acceptabilities of 10% and 39% after 21 d, respectively. We conclude that high-pressure water washing is an effective cleaning step, permitting high humidity to be used to prevent shrivel during cool-storage and subsequent ambient conditions, while minimizing the incidence of flesh rots or calyx/stem deterioration. Extended capsicum quality in high humidity at room temperature suggests that (a) cool-storage during transport to some markets may not be necessary if fruit are cleaned to a high standard and (b) fruit could remain within a box liner right up until the product is displayed on the supermarket shelves.     

Deployment of low-level ozone-enrichment for the preservation of chilled fresh produce

Tomatoes, strawberries, table grapes and plums were inoculated with Botrytis cinerea (grey mould), transferred to chilled storage (13 °C) and exposed to ‘clean air’ or low-level ozone-enrichment (0.1 μmol mol⁻¹). Ozone-enrichment resulted in a substantial decline in spore production as well as visible lesion development in all treated fruit. Exposure-response studies performed specifically on tomato fruit (exposed to concentrations ranging between 0.005 and 5.0 μmol mol⁻¹ ozone) revealed lesion development and spore production/viability to be markedly reduced in produce exposed to ozone prior to, or following, infection with B. cinerea; higher concentrations/duration of exposure yielding greater reductions in lesion development and spore production/viability. Impacts on Botrytis colonies grown on Potato Dextrose Agar (PDA) for 5–6 days at 13 °C and 95% relative humidity (RH) revealed less effects than studies on fruit inoculated with the pathogen in vivo. Taken as a whole, the results imply that ozone-induced suppression of pathogen development is due, to some extent, to impacts on fruit–pathogen interactions. This work suggests that ozone may constitute a desirable and effective residue-free alternative to traditional postharvest fungicide practices. Data presented illustrate that optimal ozone treatment regimes are likely to be commodity-specific and require detailed investigation before such practices can be contemplated commercially.     

Ripening behavior and quality of modified atmosphere packed ‘Doyenne du Comice’ pears during cold storage and simulated transit

The effect of MAP on extending storage life and maintaining fruit quality was studied in ‘Doyenne du Comice’ (Pyrus communis L.) pears at Hood River and Medford, Oregon. Control fruit packed in standard perforated polyethylene liners started to show senescent core breakdown and lost the capacity to ripen at 20 °C after 4–5 months of cold storage in Hood River and after 5.25–6 months in Medford. LifeSpan^® L257 MAP achieved steady-state atmospheres of 15.8% O₂ + 3.7% CO₂ in Hood River and 15.7–17.5% O₂ + 3.8–5.7% CO₂ in Medford. MAP inhibited ethylene production, ascorbic acid degradation and malondialdehyde accumulation, and extended storage life for up to 6 months with maintenance of fruit flesh firmness (FF) and skin color without commercially unacceptable level of physiological disorders. After 4, 5 and 6 months at −1 °C, MAP fruit exhibited climacteric-like patterns of ethylene production and softened to proper texture with desirable eating quality on day 5 during ripening at 20 °C. After 6 months at −1 °C plus 2 weeks of simulated transit conditions, MAP fruit maintained FF and skin color and had good eating quality at transit temperatures of 2 and 4.5 °C (10.1–11.5% O₂ + 4.8–5.2% CO₂), but reduced FF substantially and developed internal browning disorder at 7.5 and 20 °C (3.2–7.2% O₂ + 7.9–9.5% CO₂). The storage life of ‘Doyenne du Comice’ pears with high eating quality could be increased by up to 2 months when packed in MAP as compared with fruit packed in standard perforated polyethylene liners.     

Postharvest UV-B irradiation maintains sensory qualities and enhances antioxidant capacity in tomato fruit during storage

Mature-green tomato fruit (Lycopersicon esculentum cv. Zhenfen 202) were exposed to different doses of UV-B irradiation (10, 20, 40 and 80 kJ/m²) and stored in the dark at 14 °C, 95% RH for up to 37 d. Of the four doses, 20 or 40 kJ/m² was most effective in maintaining a high level of firmness and delaying the colour development. Furthermore, 20 or 40 kJ/m² promoted the accumulation of total phenolics and total flavonoids, and enhanced antioxidant capacity during storage, though UV-B irradiation could reduce the ascorbic acid content. A dose of 10 kJ/m² had similar effects but to a lesser extent. The highest dose of 80 kJ/m² resulted in higher lycopene content, but showed negative effects on texture, colour, and other antioxidants. The optimum dose of UV-B for maintaining sensory qualities and enhancing antioxidant capacity was 20 or 40 kJ/m². These results suggest that UV-B irradiation appears to be a useful non-chemical way of maintaining postharvest quality and enhancing antioxidant capacity in tomato fruit.     

Effect of 1-methylcyclopropene (1-MCP) on storage life of durian fruit

Fruit of cv. Monthong durian (Durio zibethinus) were treated with 0 (control) or 500 nL L⁻¹ 1-MCP for 12 h at 25 °C. Fruit were then stored at 15 °C. To determine storage life, every 3 days a batch of fruit was transferred to 25 °C. The time to ripeness (adequate eating quality) at 25 °C in controls (no 1-MCP) decreased from 5 days in freshly harvested fruit to 3 days after 18 days of storage at 15 °C. Storage life was considered adequate if the time to ripeness was ≥3 days. The storage life at 15 °C of control fruit (no 1-MCP) was therefore 18 days. After the 1-MCP treatment the time to ripeness at 25 °C was 7 days in fresh fruit, while in fruit stored at 15 °C for 30 days it was about 3 days. The storage life at 15 °C of 1-MCP-treated fruit was therefore 30 days. Pulp firmness and pulp total soluble solids (TSS) were determined after 3 day storage intervals at 15 °C and when the fruit was ripe at 25 °C. These parameters were only slightly affected by the 1-MCP treatment. Furthermore, 1-MCP had no effect on pulp color, but delayed yellowing of the fruit exterior. It is concluded that treatment with 1-MCP before storage at 15 °C extended storage life from 18 to 30 days.