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Fruit of pepper (Capsicum annuum L.) is hollow by nature, which limits its water reservoir capacity, and as such, small amounts of water loss result in loss of freshness and firmness, which reduce fruit quality, shelf life, and market value. In order to understand the basis for water loss from fruit, 10 pepper accessions with wide variation in water loss rate were used to study physiological and biochemical factors associated with postharvest water loss in ripe pepper fruit during storage. Postharvest water loss rate in ripe pepper fruit stored at 20 °C, and 85% relative humidity, was found to be associated with cell membrane ion leakage, lipoxygenase activity, and total cuticular wax amount. Total cuticular wax amounts were highest in the high-water-loss pepper fruit, and lowest in the low-water-loss fruit. However, total cuticle amount (isolated enzymatically and quantified gravimetrically), total cutin monomer amount, and the amount of individual cutin monomer and wax constituents (determined using gas chromatography mass spectrometry) indicated no direct association with postharvest water loss rates. Fruit fresh weight, pericarp weight, pericarp surface area, pericarp thickness, initial water content, and dry matter were highly associated with each other, but less so with water loss rate. Fruit of accessions displaying high fruit water loss rate matured and ripened earlier than fruit of accessions displaying low-water-loss rate. Cell membrane ion leakage and lipoxygenase activity were higher after storage than immediately after harvest. Pepper fruit total cuticle wax amount, lipoxygenase activity, and cell membrane ion leakage were directly related to postharvest water loss rate in pepper fruit during storage.

The rapidly ripening summer apple cultivar ‘Anna’ was treated with 0.1 and 1 μl l−1 1-methylcyclopropene (1-MCP) at harvest and held at 20 °C for 12 days, or stored for 5 weeks at 0 °C and then transferred to 20 °C for 10 days. Fruit quality parameters of firmness, soluble solids and titratable acidity were measured instrumentally at different times during the 20 °C ripening periods, and compared to the sensory ratings of a trained panel and hedonic scores of untrained tasters. 1-MCP prevented softening and acidity loss in the treated apples and this was reflected in the sensory ratings of the panel and the preference of the untrained tasters. Nine descriptors which showed a sample effect were overall odor, fruit odor, sweet, sour, ripe, firm, crisp, juicy and mealy. The sensory assessment of 1 μl l−1 1-MCP-treated apples remained similar to that of harvested fruit, being assessed high in firmness, crispiness and juiciness, while the control fruit after 6 days or longer at 20 °C showed the sensory characteristics of ripe fruit. Fruit treated with 0.1 μl l−1 1-MCP retained the characteristics of harvested fruit for 6 days at 20 °C, but after 12 days there were no differences between its profile and that of control fruit. The hedonic scores showed that the highest preference was for 1 μl l−1 1-MCP-treated apples after 12 days at 20 °C. This study indicates that there is a high value placed on apple fruit texture, and that 1-MCP can enable rapidly ripening summer apples to maintain the texture characteristics that are preferred by consumers.

The goal of this work was to evaluate the external, internal and sensory traits of ‘Galia’-type melon fruit coated with three polyethylene-based waxes with different solid matter and shellac contents (‘Zivdar’, ‘Tag’ and ‘Tag-A’) or with natural beeswax (‘Beeswax’). After 14 days at 5 °C plus 3 days at 20 °C, the polyethylene-based wax ‘Tag’ was found to maintain both external and internal fruit quality as evaluated by weight loss, firmness, colour development, decay incidence, and soluble solids content. Tag-treated melons also had better sensory quality, as evaluated by organoleptic tests and aroma volatiles. Treatment with the waxes ‘Zivdar’ and ‘Tag-A’, which contain high amounts of shellac in proportion to ‘Tag’ and ‘Beeswax’, significantly increased off-flavour in the melon fruit due to high-internal levels of CO 2 , ethanol, acetaldehyde and ethyl acetate. Untreated fruit, or fruit that were coated with ‘Beeswax’ had the best taste and enhanced ethyl butanoate—(responsible for fruity-pleasant notes), butyl acetate and 2-methyl propyl acetate. Despite the improved organoleptic quality, control and ‘Beeswax’-treated fruit suffered from high-decay incidence and soft texture. Overall good quality and sensory attributes of ‘Galia’-type melon can be achieved by using waxes that contain no, or very low amounts, of shellac. These waxes reduce water loss, improve the general appearance and maintain pleasant, sweet and fruity aroma notes of the fruit even after prolonged storage.

This review summarizes the latest developments in hot water immersion treatment (HWT) and hot water rinsing and brushing (HWRB) technologies. These treatments kill pathogens that cause surface decay, while maintaining fruit quality during prolonged storage and marketing. They also are relatively easy to use, have a short operating time, and are efficient in heat transfer. The cost of a typical hot water technology commercial system is significantly less than that of a commercial vapor heat treatment system. The physiological responses of cultivars of different fruit species to heat treatments vary according to season, growing location, soil type, production practices and fruit maturity. In general, the higher the temperature, the shorter the treatment in order to avoid heat damage. HWT is applied at temperatures between 43 and 53 °C for periods of several minutes up to 2 h for quarantine treatments, while HWRB is employed commercially for 10–25 s at temperatures between 48 and 63 °C. The time and temperature of exposure that benefits fresh harvested quality depends on cultivar, fruit maturity, fruit size and condition during the growing season. Both HWT and HWRB inhibit ripening, reducing decay incidence and in several commodities induce resistance against pathogens and against chilling injuries.

The purpose of this work was to evaluate the sensory and general quality of four different melon cultivars (Cucumis melo L.) immediately after harvest and at the end of storage and marketing simulation. After 16 days of storage at 5 degrees C and additional 3 days at 20 degrees C, only cultivar 'C-8' had a poor general appearance due to significant low firmness and relatively high decay incidence compared to the cultivars '5080', 'Ideal' and '7302'. The cultivar '7302' was found to have the higher overall quality. The human-sensory and organoleptic analyses revealed that the cultivars can be differentiated on the basis of retronasal odour. The texture of the melons seems to be dependent on the genotype. All the complex perceptions analysed in this work contribute to the acceptability, which is in the fresh fruits of '7302' the best and in 'Ideal' the worst. After storage and marketing simulation 'Ideal' and 'C-8' are no longer favoured, but '5080' and '7302', despite different characters, were found to be similarly accepted. It can be concluded that with the aid of the human-sensory method developed to characterize the melon varieties it is possible to distinguish the different genotypes.

Tomato fruit cracking occurs both during ripening and after harvest. Cracked fruits cannot be marketed and the cracks form sites for fungal penetration and infection. An assay based on immersion of the fruit in water was developed to study factors involved in fruit cracking. Adding calcium to the water reduced cracking whereas chelating agents increased cracking. Mineral analysis of the fruit following calcium treatment demonstrated an increase in bound calcium, while CDTA reduced the amount of soluble calcium. Decrease in fruit weight associated with water loss during storage was correlated with a decrease in the cracking potential of the fruit. Conversely, ripening during storage resulted in an increase in the cracking potential. Immersion of the fruit in acidic phosphate or citrate buffers promoted cracking whereas neutral or basic buffers prevented cracking. The cracking potential of cherry tomatoes was high after morning harvest, and it declined at noon and was low after evening harvest. It is anticipated that this study will assist to evaluate positive or negative practices which may influence cracking of cherry tomatoes after harvest.

The rapidly ripening summer apple cultivar Anna was treated with 0.1 micro L(-1) and 1 microL L(-1) 1-methylcyclopropene (MCP) at harvest and kept at 20 degrees C, or stored for 5 weeks at 0 degrees C and then transferred to 20 degrees C. Total volatiles were not reduced by treatment with 0.1 microL L(-1) MCP, but were 70% lower in fruits treated with 1 microL L(-1) MCP than in untreated fruits. Ethylene production was 50% and 95% inhibited by 0.1 microL L(-1) and 1 microL L(-1) MCP, respectively. The volatiles produced by fruit at harvest were predominantly aldehydes and alcohols, with some acetate esters as well as 2-methyl butyl acetate and beta-damascenone. During ripening, the acetate and butyrate esters increased greatly and alcohols and aldehydes decreased. MCP-treated apples retained more alcohols, aldehydes, and beta-damascenone volatiles than did untreated apples. Sensory evaluation found that control and 0.1 microL L(-1) treated apples developed more fruity, ripe, and overall aromas, but the preference was for the 1 microL L(-1) treated apples with a less ripe aroma.

The production of acetaldehyde, ethanol, ethylene and carbon dioxide by ripening tomatoes at 22 °C was measured following inoculation with a spore suspension of Botrytis cinerea. The aim was to determine whether infections could be detected before the disease symptoms became evident. Decay became visible between days 2 and 3 following inoculation. However, ethylene could be detected more than 24 h before the first decay symptom was visible. A marked increased in CO 2 could be detected only at day 4 from inoculation and was associated with decay development. Acetaldehyde evolution in Botrytis -inoculated fruit increased from day 3 to 5 from inoculation and then declined, while a marked increase in ethanol evolution was detected from day 5 only. Ethylene might be used as an early marker for infection in harvested fresh produce.

Two different heat treatments were compared as to their efficacy in preventing decay and maintaining post-harvest quality of Golden Delicious ( Malus domestica Borkh). The apples were treated with a hot water rinsing and brushing machine (HWRB) for different temperatures, and compared to apples given a dry heat treatment (96 h at 38°C) and untreated apples. HWRB at 55°C for 15 s significantly reduced (at P =0.05) decay development in Penicillium expansum -inoculated fruit after 4 weeks at 20°C, or in naturally infected fruit after prolonged storage of 4 months at 1°C plus 10 days at 20°C. This treatment inhibited ripening processes as measured by relatively low respiration rate and ethylene evolution and a slow colour development, compared with non-heated control, and fruit quality was maintained. Heat damage was observed on fruit rinsed and brushed at 60 or 65°C for 15 s. Although similar results were obtained in decay control and fruit quality of HWRB-55°C treated fruit and dry heated fruit, the commercial application of this short pre-storage heat treatment is more feasible than the dry heat treatment.

The aroma development in two Israeli ‘Galia’ melon cultivars ( Cucumis melo var .reticulans , cv. C8 and cv. 5080), was monitored. Sensory assessment was also performed, along with measurements of firmness, colour, total soluble solids, and decay incidence. A new kind of mass spectrometric sensor measurement for aroma analysis was coupled with the headspace SPME-GC method. Generally, cv. C8 fruit had higher levels of aroma volatiles than cv. 5080 fruit, but a shorter shelf life. However, cv. 5080 fruit was firmer and had higher sugar contents and therefore, was more acceptable to consumers. In order to get the best quality, fruit should be harvested when light yellow with some green areas (colour 3). During maturity, 2-methylbutyl acetate, hexyl acetate, butyl acetate, 3-hexenyl acetate, and isobutyl acetate levels increased when the peel colour turned from green to light yellow. After applying multivariate statistics to the mass spectrometric sensor data obtained from the individual melon samples, separated factor groups were obtained from different postharvest examinations. A rapid and reliable prediction of the optimal harvest date is possible for both melon cultivars, based on the measured aroma profiles.

A rapid method for simultaneously rinsing and disinfecting fresh harvested produce using a hot-water rinse and brushes (HWRB) was tested on Galia melon (Cucumis melo cv. reticulatus) fruit. The optimal treatment to reduce decay while maintaining fruit quality after prolonged storage and marketing simulation was 59 ± 1°C for 15 s. Trial shipments by sea transport to Europe demonstrated that treating melon with a commercial-scale HWRB machine (3 tonnes fruit h−1) maintained significantly better overall quality of treated fruit compared with untreated fruit. Exposing spores of Alternaria alternata and Fusarium solani to 60°C for about 15 s in vitro reduced germination by 48% and 42%, respectively. Employing HWRB resulted in a 3-log reduction in total colony-forming units (CFU) of the epiphytic microbial population, compared with untreated fruit. Scanning electron microscopy (SEM) showed that HWRB removed soil, dust and fungal spores from the fruit surface, and partially or entirely sealed natural openings in the epidermis.

Distribution of high-quality litchi ( Lychee chinensis Sonn.) fruits to global markets depends exclusively on postharvest treatments to suppress peel browning. The current standard treatment of litchi fruits in Israel includes fumigation with sulfur dioxide (SO 2 ) followed by dipping the fruits in hydrochloric acid containing the fungicide prochloraz. As part of the effort to reduce the use of potentially hazardous chemicals in agriculture, we developed a new procedure that may enable SO 2 to be avoided. Instead of fumigation, litchi fruits are sprayed with hot water while being brushed in a revolving drum, after which the fruits are subjected to hydrochloric acid treatment. Fruits that are processed in this way maintain a uniform red color for at least 35 days, without apparent deterioration in external or internal quality, or taste. Physiological studies demonstrate that polyphenol oxidase (PPO) activity is reduced by the hot water brushing (HWB) procedure as compared with controls but not to the same extent as inhibition by SO 2 treatments. In addition to its effect on PPO activity, HWB may lead to reduced pH of the pericarp, or more uniform distribution of the acid in it. This result suggests that HWB may act by bruising the external layer of the pericarp allowing the peel to be uniformly exposed to the acid which may inhibit PPO activity and maintain the anthocyanins in their red-pigmented form.

The marketing of organic citrus fruit has markedly increased during the last few years. However, these fruits are not treated with chemical fungicides and suffer from relatively high rates of decay. In this study, we examined the possible use of a new hot water brushing (HWB) treatment, to disinfect the fruits and reduce decay development during postharvest storage. Preliminary observations have shown that a minimum exposure period of 20 s at 56°C was required to inhibit Penicillium digitatum (Pers.: Fr.) Sacc spore germination in vitro. In vivo studies, carried out by rinsing and brushing the fruit 24 h after artificial inoculation with a P. digitatum spore suspension, indicated that HWB at 56, 59 and 62°C for 20 s, reduced decay development in the infected wounds to only 20, 5 and less than 1%, respectively, of that in untreated control fruits or fruits treated with tap water. The effects of HWB at 56, 59 and 62°C for 20 s on epiphytic microflora, was further confirmed by the reduction of the microbial counts (CFU) on the fruit surface to only 24, 12, and less than 1%, respectively, of those on fruit that had been rinsed and brushed with tap water. Scanning electron microscopy showed that HWB at 56°C for 20 s had smoothed the fruit epicuticular waxes and thus covered and sealed stomata and cracks on the fruit surface, which could have served as potential pathogen invasion sites. Postharvest storage experiments using various organically grown citrus cultivars such as ‘Minneola’ tangerines, ‘Shamouti’ oranges and ‘Star Ruby’ red grapefruit, showed that HWB at 56°C for 20 s reduced decay development by 45–55%. The HWB treatment at 56°C did not cause surface damage, and did not influence fruit weight loss or internal quality parameters.

SummaryPostharvest heat treatments have been used for many years as alternatives to chemical control of fungal diseases and insect infestation of fruits and vegetables. In this study, the effects of a new hot-water brushing (HWB) treatment on the resistance of red grapefruit (C. paradisi cv. Star Ruby) to green mould decay caused by Penicillium digitatum (Pers.: Fr.) Sacc. and on the development of chilling injury (CI) symptoms during cold storage were examined. The HWB treatment comprises rinsing hot water on the fruits as they move along a belt of brush rollers. A twenty second HWB treatment at 59 or 62° reduced decay, after arti®cial inoculation of wounded fruit, by 52 or 70%, respectively, compared with control unwashed fruit, whereas rinsing and brushing the fruit with tap water (~20°) or with hot water at 53 or 56°, were ineffective. HWB treatments applied 1–3 d prior to inoculation were most effective in enhancing the disease resistance of fruit, but were much less effective when the fruit were ino...

A combined hot water spray and fruit brushing (hot water brushing–HWB) treatment for 15–20 s was developed for reducing the incidence of postharvest disease caused by Alternaria alternata and improving mango fruit keeping quality. The efficacy of the hot water treatment was tested over a range of temperatures from 48 to 64°C, in combination with prochloraz treatment and fruit waxing. Hot water brushing of fruits significantly reduced decay (infected area) development by A. alternata. But after storage for 3 weeks at 12°C and another week at 20°C, the reduction of disease incidence by HWB and prochloraz treatment (900 μg ml−1) was more effective than by HWB alone. HWB treatment for 15 s improved colour development and was more effective than the common, commercial 5 min dip treatment at 55°C. The combination of fruit HWB and waxing yielded high quality fruits with less decay development.

A unique and rapid method for simultaneously rinsing and disinfecting sweet pepper ( Capsicum annuum L.) using hot water and brushes has been developed (Israeli patent 116965). The efficiency of this method was tested on both laboratory and commercial scale machines with several bell sweet pepper varieties. The optimal treatment for cleaning and disinfecting pepper while maintaining fruit quality after prolonged storage and marketing simulation was found to be 55±1°C for 12±2 s. This treatment significantly improved the general appearance of the fruit, reduced decay incidence and maintained fruit firmness. The respiration rate of rinsed and cleaned fruit was significantly lower than that of untreated fruit during storage and shelf life simulation. Rinsed and disinfected sweet peppers from a commercial-scale operation (1.5 tonnes h −1 ) and commercial dry-brushed fruits (control) were sent from Israel to England and the overall quality examined after 15 days storage at 7°C and an additional of 4 days at 16–18°C. Treated fruits were markedly firmer and cleaner than commercial dry-brushed fruit and were almost free of rots. Scanning electron microscopy (SEM) showed that this method removed dirt, dust and even fungal spores from the fruit calyx and skin and that small invisible cracks in the epidermis were sealed, thus maintaining better keeping quality of the fruit.

Some plant-derived natural volatile compounds exhibit antifungal properties and may offer an opportunity to control the causes of postharvest spoilage without affecting quality of, or leaving a residue on, fresh produce. The natural wound volatile (E)-2-hexenal has exhibited significant antifungal activity in earlier studies, but effects on spore germination and mycelial growth have not been separated, nor has the inhibitory mode of action been determined. To determine the efficacy of (E)-2-hexenal for control of Botrytis cinerea Pers. ex Fr. spore germination and mycelial growth, and to examine the mode of action, in vitro and in vivo studies were performed. Under in vitro bioassay conditions, spore germination was more sensitive to the compound than was mycelial growth. Vapor from 10.3 μmol of (E)-2-hexenal in a 120-mL petri dish completely inhibited spore germination. However, 85.6 μmol of (E)-2-hexenal was required to completely inhibit mycelial growth. Lower concentrations of the compound (5.4 and 10.3 μmol) significantly stimulated mycelial growth, especially when the volatile was added 2 days following inoculation. Mycelial growth did not occur as long as the vapor-phase concentration was 0.48 μmol·L-1 or greater. Light microscopy analysis indicated that a high concentration of volatile compound dehydrated fungal hyphae and disrupted their cell walls and membranes. Exposure of B. cinerea-inoculated and non-inoculated strawberry (Fragaria ×ananassa Duch.) fruit in 1.1-L low-density polyethylene film-wrapped containers to vapor of (E)-2-hexenal at 85.6 or 856 μmol (10 or 100 mL, respectively) per container for durations of 1, 4, or 7 days during 7 days of storage at 2 °C promoted the incidence of B. cinerea during subsequent shelf storage at 20 to 22 °C. Loss of fruit fresh mass and fruit firmness during storage at 22 °C was increased by (E)-2-hexenal treatment, but fruit total soluble solids, pH, titratable acidity, and color (L, C, and H values) were not affected. Thus, maintenance of a high vapor-phasel level of (E)-hexenal, perhaps >0.48 μmol·L-1, may be necessary to inhibit mycelial growth and avoid enhancing postharvest mold problems, while significantly higher levels may be necessary to completely eliminate the pathogen.

Postharvest heat treatments have been proposed as non-chemical means for enhancing storage of fruits and vegetables. Various regimes of time and temperature in either hot air or hot water maintain fruit firmness and diminish the incidence and severity of pathological diseases. Treatment with calcium, alone or in combination with heat, has similar beneficial effects. Little attention has been paid to the organoleptic effect of these treatments, upon which consumer acceptability ultimately rests. We heated (38°C, 3 d) mature-green or pink tomatoes (Lycopersicon esculentum, L., cv. 'Daniella') and measured overall consumer preference after the fruit were stored at 12°C for 10 d. Heated and non-heated fruit were rated similarly for acceptability by a taste panel, with no off-flavours being detected. Apples (Malus domestica, Borkh., cv. 'Golden Delicious') were infiltrated with 2% calcium chloride, or heated (38°C, 4 d), or heated and then infiltrated prior to 6 months' storage in air at 0°C. A range of flavour and texture attributes were then rated by tastes panellists. Heated and/or calcium-treated fruit were perceived as crisper, sweeter, and overall more acceptable than untreated fruit. We conclude that, in addition to conferring physiological benefits on stored tomatoes and apples, heat and calcium treatments do not damage and may even improve consumer acceptability.

The efficacy of a prestorage dry heat treatment and a hot water dip was investigated for reducing storage rots on bell peppers and tomatoes. The best results were obtained with hot air at 38°C for 48 to 72 h or hot water at 50 to 53°C for 2 to 3 min. Under these conditions in vitro germination and growth of Alternaria alternata and Botrytis cinerea were weakened or prevented. The effect of the heat treatment in vivo was more pronounced, and fungal development was prevented on inoculated fruits. Following the heat treatment the produce could be stored at low temperature without developing chilling injury. The dry heat treatment was also effective in preventing the development of insect pests such as Ceratitis capitata Weidmann (medfly). This is the first report of a single heat treatment being able to control fungal and insect pests and beneficially affect fruit physiology.

Postharvest heat treatments were applied to three apple (Malus domestica Borkh.) cultivars: `Anna', `Golden Delicious', and `Jonathan'. The temperatures ranged from 38 to 50 °C and from 5 to 96 hours. The temperatures of 50 °C for 5 or 10 hours and 46 °C for 10 hours controlled all developmental stages of San Jose scale on `Golden Delicious' and `Jonathan' fruit. Blue mold germination was prevented by 46, 42, and 38 °C after 28, 34, and 42 hours, respectively. The time needed to control the fungus was longer than that required to kill the insect. Apples were damaged by a 50 °C treatment but could withstand at least 12 hours at 46 °C and at least 24 hours at 42 °C. At 38 °C no damage was found on preclimacteric apples even after 96 hours, but if postclimacteric fruit were heated at 38 °C heat damage occurred. The treatments that did not cause damage maintained the fruit firmness during post storage ripening. The results are discussed in the context of developing integrated postharvest heat treatments.

Volatile compounds were collected by porous polymer trapping from Golden Delicious apples (Malus domestica Borkh.) that had been heat-treated for 4 days at 38 °C, a treatment developed to reduce physiological and pathological disorders during storage, and then stored at 1 °C. Heat treatment of apple fruits markedly inhibited emission of total volatile esters (compounds commonly associated with apple aroma) and total volatiles (comprised principally of the volatile esters and α-farnesene) of apple within 1 day of treatment. However, after an extended refrigerated storage at 1 °C, the heat-treated fruit recovered and produced more total volatiles, increasing from 4% compared to non-heat-treated fruit directly after heat treatment to 145% of non-heat-treated fruit after 6 weeks of storage. Total volatile production of non-heat-treated fruit declined over 5-fold during the 6 weeks of cold storage, while that of heat-treated fruit increased over 6-fold. Total volatile esters from heat-treated fruit declined af...

Tomato fruits are sensitive to low temperature and develop chilling injury, while at nonchilling temperatures they ripen rapidly. Previously, a hot-air treatment was found to reduce the sensitivity of the fruit to low temperatures. In the present study hot air was compared to hot water and their effects on reducing chilling injury and fungal decay were investigated. Tomatoes (Lycopersicon esculentum cv. Daniella) at the breaker stage were subjected to hot air, 48 h at 38°C, or various hot water dips, 30 min at 40°C or 2 min at 46, 48 or 50°C, before holding at 2°C. The unheated tomatoes developed chilling injury and fungal infections at 2°C, but not at 12°C. All the heat treatments reduced chilling injury and decay in tomatoes held for 3 weeks at 2°C. The outer pericarp tissue of heated tomatoes had higher phospholipid and lower sterol contents than unheated tomatoes. Heated tomatoes also had less saturated fatty acids than unheated tomatoes held at 2°C, but not at 12°C. Scanning electron micrograph observations showed that all the fruits had microcracks in their surface, but the unheated chilled tomatoes had also fungal growth in the cracks, while those of the heated tomato fruit did not. In the areas of chilling injury collapsed cells were present under the peel and could also support pathogen development. It is suggested that the heat treatment institutes a response to high temperature stress in the fruit tissue that leads to strengthened membranes. This prevents the loss of function and cell collapse which was found in the chilling-injured areas of affected fruit.

Sodium bicarbonate (SBC) inhibited in vitro mycelial growth of A. alternata, Fusarium spp. and R. stolonifer. SBC action was fungistatic rather than fungicidal. Coating commercially harvested ‘Galia’ and ‘Ein-Dor’ melons with wax containing 2% SBC reduced decay incidence after storage and shelf life simulation by four to seven-fold, to a commercially acceptable level of 6–7%, compared to untreated or waxed-treated controls. This treatment also maintained the fresh and blemish-free appearance of the fruit at harvest. Higher concentrations of SBC (3%) were phytotoxic and significantly reduced general fruit appearance. A trial shipment by sea transport to Europe demonstrated that 2% SBC incorporated into a wax coating maintained the marketability of ‘Galia’ melon fruits compared to that of untreated fruit. SBC can be an alternative biocide to the fungicide imazalil, thus eliminating unwanted residues on melon fruits.

Golden Delicious apples (Malus domestica Borkh) were heated for 4 days at 38 °C and then dipped in 2% CaCl2, or dipped in the solution without prior heating. Scanning electron micrographs of the fruit wax layer after three days of 0 °C storage showed that the heated apples had areas of amorphous wax and fewer surface cracks than unheated apples. There was less wax on the surface of heated than on unheated apples. Electron density scan of apple wax showed more calcium in outer than inner wax area of undipped but heated apples, while the opposite obtained in unheated apples. Dips in calcium raised the wax calcium level of the unheated apples more than the heated ones. Plasma emission spectrometry of calcium in apple peel and flesh after 5 months storage at 0 °C showed greater penetration of calcium from the dips into unheated apples, compared to heated apples. It is suggested that during the heat treatment the wax softens and fills in cracks while water loss pulls calcium towards the fruit surface. This continuous wax layer on heated fruit decreases the ability of external calcium to move into the apple.

The effectiveness of hot water dipping on the control of grey mould, caused by Botrytis cinerea, and black mould, caused by Alternaria alternata on sweet red pepper quality was investigated. Dipping naturally infected or artificially inoculated fruit at 508C for 3 min completely inhibited, or significantly reduced, decay development caused by B. cinerea and A. alternata, respectively. Heat damage was observed on fruit dipped for 5 min at 50°C, or at 55°C for 1 min or longer. Damage appeared as cracks and pitting on the fruit surface. Spore germination and germ tube elongation in vitro was inversely related to the duration of exposure or to the range of temperature used. The ET50 for spore germination for B. cinerea was 3.2, 1.5 and 0.8 min, and for A. alternata 8.8, 4.2 and 1.4 min, at 45, 50 and 55°C, respectively. The ET50 for germ tube elongation for Botrytis was 2.6, 0.9 and 0.5 min, and for Alternaria, 7.2, 2.5 and 1.6 min, at 45, 50 and 55°C. The mode of action of hot water dips on decay of pepper appears to be by direct interaction with the fungi.

Penicillium expansum is one of the main postharvest pathogens of apples in Israel. Heating apple fruit inoculated with P. expansum for 96 h at 38°C completely inhibited decay development. Fruit held for 24 h at 42°C or 12 h at 46°C had significantly reduced decay after an additional 14 days incubation at 20°C, compared with unheated inoculated control fruit. Mycelial growth and percentage spore germination in vitro were inversely proportional to length of time of exposure to various temperatures. The ET50 for spore germination was 42, 34 and 20 h at 38, 42 and 46°C, respectively, while the ET50 for mycelial growth was 48, 44 and 36 h at those temperatures. When Penicillium spores were incubated on crude extract prepared from the peel of apple fruits held 4 days at 38°C, germ tube elongation was significantly reduced, while the walls of the tubes were thicker, compared with germ tubes from spores incubated on crude extract prepared from peel of non-heated fruit. The evidence presented here supports the hypothesis that the effect of heating on the decay of apples caused by P. expansum is not only the result of direct inhibition of fungal germination and growth by high temperature, but is also partly due to the formation of an inhibitory substance in the heated peel.

We grew Azospirillum brasilense biomass in fed-batch culture for 28 h using succinic acid as a C source and liquid NH 3 as N source. Viable cell concentration reached 1–3 × 10 10 CFU ml −1 after 28 h. Ground or granular peat, serving as carriers for the bacteria, maintained the highest number of A. brasilense compared to vermiculite, talcum powder, basalt granules or bentonite. A. brasilense viable counts declined from about 10 10 CFU g −1 peat to 10 5 –10 6 CFU g −1 peat after 6 months. A pot system for evaluating the effect of A. brasilense inoculants on plant growth in greenhouses demonstrated that application of peat-carrier containing 10 8 CFU g −1 peat, significantly increased panicle length and dry weight of Setaria italica and ear and kernel weight of maize ( Zea mays L). Highest growth promotion effects on maize were observed when using A. brasilense cells containing 40% polyhydroxybutyrate (PHB) and by applying the peat inoculant 2 cm below the maize seed.

Sweet corn cobs can be transported for sale in distant markets after being sealed in Polyvinylchloride (PVC) film to delay quality loss through the reduction of water loss and shrivelling. However, this package does not prevent decay of the cut ends. Polyolefin films, AM and K-400T, were tested as substitutes for PVC as an overwrap for sweet corn placed on either cardboard (CB) or polystyrene (PS) trays. Increased levels of CO 2 and decreased oxygen atmospheres were generated through the use of the new films compared with PVC, which reduced decay, and maintained quality during 12 days storage at 1 °C and two days at 20 °C. CB trays were found to be preferable to PS ones.

The keeping quality of red bell pepper (Capsicum annuum) is relatively low, since the fruits are sensitive to low temperature (

The quality of eggplant fruit (Solanum melongena L.) during prolonged storage may be impaired by the susceptibility of the fruits to deterioration and chilling injury at low temperature (

The fruit of pepper (Capsicum annuum) commonly wilts (or shrivels) during postharvest storage due to rapid water loss, a condition that greatly reduces its shelf life and market value. The fact that pepper fruit are hollow, and thus have limited water content, only exacerbates this problem in pepper. The collaborators on this project completed research whose findings provided new insight into the genetic, physiological, and biochemical basis for water loss from the fruits of pepper (Capsicum annuum and related Capsicum species). Well-defined genetic populations of pepper were used in this study, the first being a series of backcross F₁ and segregating F₂, F₃, and F₄ populations derived from two original parents selected for having dramatic differences in fruit water loss rate (very high and very low water loss). The secondly population utilized in these studies was a collection of 50 accessions representing world diversity in both species and cultivar types. We found that an unexpectedly large amount of variation was present in both fruit wax and cutin composition in these collections. In addition, our studies revealed significant correlations between the chemical composition of both the fruit cuticular waxes and cutin monomers with fruit water loss rate. Among the most significant were that high alkane content in fruit waxes conferred low fruit water loss rates and low permeability in fruit cuticles. In contrast, high amounts of terpenoids (plus steroidal compounds) were associated with very high fruit water loss and cuticle permeability. These results are consistent with our models that the simple straight chain alkanes pack closely together in the cuticle membrane and obstruct water diffusion, whereas lipids with more complex 3-dimensional structure (such as terpenoids) do not pack so closely, and thus increase the diffusion pathways. The backcross segregating populations were used to map quantitative trait loci (QTLs) associated with water loss (using DART markers, Diversity Arrays Technology LTD). These studies resulted in identification of two linked QTLs on pepper’s chromosome 10. Although the exact genetic or physiological basis for these QTLs function in water loss is unknown, the genotypic contribution in studies of near-isogenic lines selected from these backcross populations reveals a strong association between certain wax compounds, the free fatty acids and iso-alkanes. There was also a lesser association between the water loss QTLs with both fruit firmness and total soluble sugars. Results of these analyses have revealed especially strong genetic linkages between fruit water loss, cuticle composition, and two QTLs on chromosome 10. These findings lead us to further speculate that genes located at or near these QTLs have a strong influence on cuticle lipids that impact water loss rate (and possibly, whether directly or indirectly, other traits like fruit firmness and sugar content). The QTL markers identified in these studies will be valuable in the breeding programs of scientists seeking to select for low water loss, long lasting fruits, of pepper, and likely the fruits of related commodities. Further work with these newly developed genetic resources should ultimately lead to the discovery of the genes controlling these fruit characteristics, allowing for the use of transgenic breeding approaches toward the improvement of fruit postharvest shelf life.

Pepper (Capsicum spp.) fruits are covered by a relatively thick coating of cuticle that limits fruit water loss, a trait previously associated with maintenance of postharvest fruit quality during commercial marketing. To shed light on the chemical-compositional diversity of cuticles in pepper, the fruit cuticles from 50 diverse pepper genotypes from a world collection were screened for both wax and cutin monomer amount and composition. These same genotypes were also screened for fruit water loss rate and this was tested for associations with cuticle composition. Our results revealed an unexpectedly large amount of variation for the fruit cuticle lipids, with a more than 14-fold range for total wax amounts and a more than 16-fold range for cutin monomer amounts between the most extreme accessions. Within the major wax constituents fatty acids varied from 1 to 46%, primary alcohols from 2 to 19%, n-alkanes from 13 to 74% and triterpenoids and sterols from 10 to 77%. Within the cutin monomers, total hexadecanoic acids ranged from 54 to 87%, total octadecanoic acids ranged from 10 to 38% and coumaric acids ranged from 0.2 to 8% of the total. We also observed considerable differences in water loss among the accessions, and unique correlations between water loss and cuticle constituents. The resources described here will be valuable for future studies of the physiological function of fruit cuticle, for the identification of genes and QTLs associated with fruit cuticle synthesis in pepper fruit, and as a starting point for breeding improved fruit quality in pepper.

Sanosil-25 is a universally applicable disinfectant compound that is highly effective against pathogenic bacteria, fungi, algae, viruses and amoebae. The compound contains 48% hydrogen peroxide (H 2 O 2 ) and 0.05% silver ion (Ag + ) as a stabilizing agent. The ED 50 for spore inhibition in vitro was 0.09% and 0.18% for Botrytis cinerea and Alternaria alternata , respectively. Germination was completely inhibited at concentrations of 0.5% and 0.7% for B. cinerea and A. alternata , respectively. The ED 50 values for mycelial growth inhibition were 0.6% and 0.7% for B. cinerea and A. alternata , respectively, but for complete inhibition the effective concentrations were 1.5% and 2.0%. The effective exposure time of fungal spores was inversely related to the concentration used. Dipping commercially harvested eggplants and sweet red peppers in 0.5% Sanosil-25 reduced decay development after storage and shelf-life to a commercially acceptable level compared with an untreated control.

Summary Sanosil-25, a disinfectant containing 48% hydrogen peroxide and silver salts as stabilising agents, inhibited the mycelial growth of the two main decays causing fungi of melons, Alternaria alternata and Fusarium solani in vitro at concentrations between 5000 and 10 000 μl litre-1. However, in in vivo experiments, Sanosil-25 markedly decreased decay at a concentration of 5000 μl litre-1 when incorporated into a wax treatment and produced no phytotoxic effect. This treatment may provide an alternative to imazalil which, although more effective, gives problems with residue levels. A concentration of 10 000 μl litre-1 proved phytotoxic.

SummaryEggplants (Solanum melongena L.) for export from Israel are currently packed individually in PVC stretch film. Wholesalers however, dislike these wraps because they must be removed prior to marketing. We investigated alternative polyethylene linings and absorbent materials for packing during the storage of eggplant fruit. The best storage method involved packing several fruit (10–15) pre-treated with a solution of fungicide and NAA, inside an unperforated polyethylene lining bag, together with ten layers of tissue paper to prevent water condensation. This method prevented weight loss and maintained fruit quality during 14 d of storage at 12°C and an additional 3 d at 20°C.

Mandarin sensory acceptability deteriorates rapidly after harvest. To gain a better understanding of the molecular processes that occur in 'Mor' mandarin flesh and contribute to flavor deterioration during storage, we performed genome-wide transcriptional profiling analysis using the Affymetrix Citrus GeneChip. Out of 30,171 probe sets representing citrus transcripts on the microarray, expression of 1,139 probe sets was significantly (q ≤ 0.01) altered by factors of at least 4 after 6 weeks of cold storage at 5 °C, of which 745 (65%) were downregulated and 394 (35%) upregulated. Overall, storage led to expression arrest of general cellular and metabolic activity, but enhanced lipid and amino acid catabolism, most probably to form substrates for the tricarboxylic acid (TCA) cycle and energy production. In addition, storage enhanced gene expression of pyruvate decarboxylase (PDC), a key enzyme in anaerobic respiration and the ethanol fermentation pathway. Taken together, we propose that induction of amino acids and fatty acids degradation leads to accumulation of volatiles involved in formation of "fruity" (overripe) and "musty" aromas, respectively, whereas induction of ethanol fermentation metabolism leads to formation of "alcohol" flavor, all of which generate off-flavors after harvest.

‘Galia’ melons (Cucumis melo cv. Reticulatus) exported from Israel to Europe are coated with wax containing 2000 ppm imazalil to control decay‐causing fungi (Alternaria alternata and Fusarium spp). The residual level on the fruit is 3–5 ppm of imazalil, and exceeds the tolerance levels of some countries (i.e., 0.5 ppm). In this study we test an alternative treatment to imazalil. Hinokitiol (β‐thujaplicin), a volatile oil extracted from the Japanese Hiba tree (Thujopsis dolabrata), at a concentration of 750 ppm in the wax, controlled the decay‐causing fungi and had no phytotoxic effect on the fruit.

There have been no previous studies on the genetics of Azotobacter paspali , an aerobic bacterium which forms a highly specific diazotrophic association with Bahia grass ( Paspalum notatum ). We constructed A. paspali strains defective in the molybdenum nitrogenase so that alternative N 2 ases could be studied. The cosmid vector pTBE and genomic DNA fragments (∼50 kb) of A. paspali ATCC 23367 were used to construct a gene library in Escherichia coli . Recombinant cosmids containing sequences homologous to molybdenum nitrogenase nifDK structural genes were identified by hybridization. A 2.9-kb fragment bearing the putative nifDK genes of A. paspali was subcloned and mutagenized in vitro by the insertion of a kanamycin resistance gene cassette. The mutation was recombined into the chromosome of A. paspali with the suicide vector pCU101. One resultant mutant strain, AP2, was incapable of diazotrophic growth in a molybdenum-containing medium (Nif - ) without vanadium but grew well in a molybdenum-deficient medium with vanadium. The nitrogenase system in AP2 reduced acetylene to ethylene and produced ethane as 2.4% of the total products. Molybdenum levels as low as 10 nM prevented the diazotrophic growth of AP2, even in the presence of vanadium at levels up to 10 μM. These results are consistent with the existence of a vanadium nitrogenase system in A. paspali .

Eggplant (Solatium melongena L.) fruits deteriorate rapidly during prolonged storage, mainly due to accelerated senescence of the calyx. Dipping the calyx in a solution containing 200 ppm NAA and 9...

During the last decade there has been a continuous rise in consumption of fresh easy-to-peel mandarins. However, mandarins are much more perishable than other citrus fruit, mainly due to rapid deterioration in sensory acceptability after harvest. In the current review we discuss the biochemical components involved in forming the unique flavor of mandarins, and how postharvest storage operations influence taste and aroma and consequently consumer sensory acceptability. What we perceive as mandarin flavor is actually the combination of basic taste, aroma and mouth-feel. The taste of mandarins is principally governed by the levels of sugars and acids in the juice sacs and the relative ratios among them, whereas the aroma of mandarins is derived from a mixture of different aroma volatiles, including alcohols, aldehydes, ketones, terpenes/hydrocarbons and esters. During postharvest storage and marketing there is a gradual decrease in mandarin sensory acceptability, which has been attributed to decreases in acidity and typical mandarin flavor, paralleling an accumulation of off-flavor. Biochemical analysis of volatile and non-volatile constituents in mandarin juice demonstrated that these changes in sensory acceptability were concomitant with decreases in acidity and content of terpenes and aldehydes, which provide green, piney and citrus aroma on the one hand, and increases in ethanol fermentation metabolism products and esters on the other, which are likely to cause 'overripe' and off-flavors. Overall, we demonstrate the vast importance of the genetic background, maturity stage at harvest, commercial postharvest operation treatments, including curing, degreening and waxing, and storage duration on mandarin sensory quality.

Mandarins suffer from accumulation of off-flavours after harvest. In this study the sensory quality and aroma profile composition of homogenised segments of untreated (control) and wax-coated 'Mor' mandarins after 7 days at 20 degrees C or 3 or 6 weeks of cold storage at 5 degrees C were examined.Fruit taste score decreased during storage and following wax coating, and this was attributed to decreases in sourness and mandarin flavour and accumulation of off-flavours. Aroma profiling identified 31 volatiles that decreased by at least 50% during storage and after waxing and thus may be involved in the observed flavour loss. In contrast, 13 volatiles, mostly belonging to ethanol fermentation and fatty acid and amino acid catabolism pathways, significantly increased at least twofold and probably contributed to off-flavour enhancement.The results showed that after harvest there was a progressive decrease in sensory quality of 'Mor' mandarins. It is proposed that observed decreases in contents of sesqui- and monoterpenes and short-chain oxygenated fatty acids may contribute to the decrease in mandarin flavour, whereas increases in the contents of ethanol fermentation metabolites and derivates of fatty acid and amino acid catabolism are most likely involved in causing the enhanced sensation of off-flavours.

Hinokitiol (β-thujaplicin), a volatile oil extracted from the roots of the Hinoki tree, Hiba arboruitae (Japanese cypress), was tested as a natural biocide to control postharvest decay pathogens. The compound inhibited in vitro spore germination and mycelial growth of Botrytis cinerea and Alternaria alternata. The ed 50 of hinokitiol for the inhibition of spore germination was 60 μl L−1 and 100 μl L−1 for B. cinerea and A. alternata, respectively. Hinokitiol completely inhibited B. cinerea spore germination at a concentration of 100 μl L−1 and that of A. alternata at 500 μl L−1. The ed 50 values for mycelial growth inhibition were 50 and 80 μl L−1 for B. cinerea and A. alternata, respectively, but for complete inhibition the effective concentrations were 250 μl L−1 and 750 μl L−1, respectively. The effective exposure time of fungal spores to hinokitiol was inversely related to the concentrations used. Very short exposures were required for 50% inhibition of spore germination at 1000 μl L−1 hinokitiol, while up to 30–40 times longer exposures were required when 10 μl L−1 was used. A marked reduction in decay development was observed when commercially harvested eggplants and red peppers were dipped in hinokitiol solution (750 μl L−1).

Publisher Summary The chapter describes the possibilities of using physical means and particularly heat treatments, to suppress the development of Aspergillus, Penicillium , and Alternaria species responsible for the accumulation of mycotoxins. Aspergillus molds are found worldwide. The genus includes over 150 species, some of which may infect fruits and vegetables and are capable of producing mycotoxins that adversely affect humans and animals health via consumption. These include alfatoxins and ochratoxin A, both of which are found to be carcinogenic. Penicillium expansum , the causal agent of the blue mold rot, is a common postharvest pathogen on apples and pears worldwide. Furthermore, Alternaria is a cosmopolitan fungus commonly isolated from plants, soil, food, and outdoor and indoor air environment. The genus Alternaria currently contains more than 50 species, among which, A. alternata is the most common one. Alternaria species are some of the most prodigious producers of toxic secondary metabolites, producing over 70 compounds of varying toxicity.

We have modified the flavor and aroma of tomatoes by expressing the Ocimum basilicum geraniol synthase gene under the control of the tomato ripening-specific polygalacturonase promoter. A majority of untrained taste panelists preferred the transgenic fruits over controls. Monoterpene accumulation was at the expense of reduced lycopene accumulation. Similar approaches may be applicable for carotenoid-accumulating fruits and flowers of other species.