Effect of postharvest biofumigation on fungal decay,sensory quality,and antioxidant levels of blueberry fruit

Postharvest decay, caused by various fungal pathogens, is an important concern in commercial blueberry production, but current options for managing postharvest diseases are limited for this crop. Four plant essential oils (cinnamon oil, linalool, p-cymene, and peppermint leaf oil) and the plant oil-derived biofungicides Sporan (rosemary and wintergreen oils) and Sporatec (rosemary, clove, and thyme oils) were evaluated as postharvest biofumigants to manage fungal decay under refrigerated holding conditions. Hand-harvested Tifblue rabbiteye blueberry fruit were inoculated at the stem end with conidial suspensions of Alternaria alternata, Botrytis cinerea, Colletotrichum acutatum, or sterile deionized water (check inoculation) and subjected to biofumigation treatments under refrigeration (7 °C) for 1 wk. Sporatec volatiles reduced disease incidence significantly (P < 0.05) in most cases, whereas other treatments had no consistent effect on postharvest decay. Sensory analysis of uninoculated, biofumigated berries was performed utilizing a trained sensory panel, and biofumigation was found to have significant negative impacts on several sensory attributes such as sourness, astringency, juiciness, bitterness, and blueberry-like flavor. Biofumigated fruit were also analyzed for antioxidant capacity and individual anthocyanins, and no consistent effects on these antioxidant-related variables were found in treated berries. Because of limited efficacy in reducing postharvest decay, negative impacts on sensory qualities, and failure to increase antioxidant levels, the potential for postharvest biofumigation of blueberries under refrigerated holding conditions appears limited.     

Determination of optimal sulfur dioxide time and concentration product for postharvest control of gray mold of blueberry fruit

Highbush blueberries (Vaccinum spp.) are a major export fruit crop of Chile which is stored at 0 °C and transported to markets in Asia, Europe, and the USA, using more than 15 d of maritime transportation. Under these conditions, gray mold caused by Botrytis cinerea can produce important economic losses. The effectiveness of sulfur dioxide (SO₂) concentration × time treatments on gray mold control was determined in the laboratory and validated prior to refrigerating the fruit, using pallet scale SO₂ fumigation treatment on the following blueberry cultivars: ‘Brigitta’, ‘Legacy’, ‘Liberty’ and ‘O’Neal’. In inoculated ‘Brigitta’ and ‘Liberty’ blueberries, gray mold prevalence varied from 97.2% to 97.5% in non-treated fruit, and this value was reduced from 7.9% to 6.1% in blueberries that were exposed to a SO₂ concentration × time (Ct) product of 400 (μL L⁻¹) h. The relationship between SO₂ Ct products and gray mold prevalence under laboratory conditions was best explained by exponential models, which had a determination coefficient (R²) that ranged from 0.88 to 0.96. The estimated EC₉₀ values varied between 245 and 400 (μL L⁻¹) h, and the SO₂ Ct between 250 and 350 (μL L⁻¹) h was validated using a pallet scale application treatment to obtain the best control and minimal variation. No visual phytotoxicity symptoms of SO₂ were observed with the Ct that was tested in this study. Therefore, SO₂ fumigation was demonstrated to be an effective and practical technology for reducing the risk of blueberry gray mold decay during storage, and further effort should be given to register the use of this product for blueberries in the main Chilean export markets.     

Potential of the biopolymer chitosan with different molecular weights to control postharvest gray mold of tomato fruit

Gray mold caused by Botrytis cinerea (Pers.) is the most economically important postharvest disease of fruit and vegetables at harvest and during storage. Therefore the current study was conducted to investigate the effectiveness of chitosan with different molecular weights on gray mold in vitro and in vivo in tomato fruit (Solanum lycopersicum L. var. lycopersicum) stored at different temperatures. In an in vitro experiment, the results demonstrated that the antifungal activity increased as the chitosan molecular weight decreased. In an in vivo study, chitosan treatments significantly reduced fungal decay and all compounds with concentrations of 2000 and 4000 mg/L showed complete control of the fungus in wound-inoculated fruit. Chitosan with a molecular weight of 5.7 × 10⁴ g/mol was the most effective compound among those tested. The results also revealed that high chitosan concentrations correlated with low disease incidence regardless of storage conditions. In addition to the antifungal activity, chitosan had the potential for the elicitation of defense markers, including total soluble phenolic compounds, polyphenoloxidase (PPO) activity and total protein content. Chitosan treatment decreased the activity of PPO and enhanced total protein and phenolic compounds in wounded tomato fruit. These findings suggest that the effects of chitosan with different molecular weights on gray mold in tomato fruit may be associated with direct fungitoxic properties against the pathogen, and the elicitation of biochemical defense responses in fruit.     

The use of pullulan coating enriched with plant extracts from Satureja hortensis L. to maintain pepper and apple quality and safety

This study determined the minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) of water and ethanol Satureja hortensis (SH) extract, as well as the antimicrobial activity of pullulan films with an addition of the extracts against test strains. The pullulan coating with an addition of water SH extract was also applied pepper and apple fruit. The concentration of bioactive compounds in the extracts was assessed using HPLC. The analysis included the effect of pullulan coating with water SH extract on weight loss and color change in peppers during storage at 16 °C/14 days, and 16 °C/28 days, and apples at 16 °C/14 days, and 2 °C/28 days. A microscopic image of the coating on materials was evaluated and sensory analysis performed. Polyphenolic compounds from phenolic acid and flavone families were identified in the extracts, and higher levels of phenolic compounds (p < 0.05) were found in the water extract. The activity of pullulan films with SH extracts increased significantly (p < 0.05) with the increase in SH extract concentration (5%, 10% and 20%). Pullulan films with water SH extract inhibited the growth of Gram-positive and Gram-negative bacteria and Penicillium expansum more strongly than was the case with those films with an ethanol SH extract. Moreover, coating application resulted in a decrease in weight loss and an extension of storage time, and also protected the material against excessive wilting and wrinkling on the surface, maintaining freshness and consumer appeal.     

Gas sensor array for blueberry fruit disease detection and classification

A conducting polymer gas sensor array (electronic nose) was evaluated for detecting and classifying three common postharvest diseases of blueberry fruit: gray mold caused by Botrytis cinerea, anthracnose caused by Colletotrichum gloeosporioides, and Alternaria rot caused by Alternaria sp. Samples of ripe rabbiteye blueberries (Vaccinium virgatum cv. Brightwell) were inoculated individually with one of the three pathogens or left non-inoculated, and volatiles emanating from the fruit were assessed using the gas sensor array 6–10 d after inoculation in two separate experiments. Principal component analysis of volatile profiles revealed four distinct groups corresponding to the four inoculation treatments. MANOVA, conducted on profiles from individual assessment days or from combined data, confirmed that the four treatments were significantly different (P < 0.0001). A hierarchical cluster analysis indicated two super-clusters, i.e., control cluster (non-inoculated fruit) vs. pathogen cluster (inoculated fruit). Within the pathogen cluster, fruit infected by B. cinerea and Alternaria sp. were more similar to each other than to fruit infected by C. gloeosporioides. A linear Bayesian classifier achieved 90% overall correct classification for data from experiment 1. Tenax? trapping of volatiles with short-path thermal desorption and quantification by gas chromatography–mass spectrometry was used to characterize volatile compounds emanated from the four groups of berries. Six compounds [styrene, 1-methyl-2-(1-methylethyl) benzene, eucalyptol, undecane, 5-methyl-2-(1-methylethyl)-2-cyclohexen-1-one, and thujopsene] were identified as contributing most in distinguishing differences in the volatiles emanating from the fruit due to infection. A canonical discriminant analysis model using the relative concentration of each of these compounds was developed and successfully classified the four categories of berries. This study underscores the potential feasibility of using a gas sensor array for blueberry postharvest quality assessment and fungal disease detection.     

Lemongrass essential oil incorporated into alginate-based edible coating for shelf-life extension and quality retention of fresh-cut pineapple

The effects of different concentrations (0.1%, 0.3% and 0.5%, w/v) of lemongrass essential oil incorporated into an alginate-based [sodium alginate 1.29% (w/v), glycerol 1.16% (w/v) and sunflower oil 0.025% (w/v)] edible coating on the respiration rate, physico-chemical properties, and microbiological and sensory quality of fresh-cut pineapple during 16 days of storage (10 ± 1 °C, 65 ± 10% RH) were evaluated. Coated fresh-cut pineapple without lemongrass and uncoated fresh-cut pineapple were stored under the same conditions and served as the controls. The results show that yeast and mould counts and total plate counts of coated samples containing 0.3 and 0.5% (w/v) lemongrass were significantly (p < 0.05) lower than other samples. However, the incorporation of 0.5% (w/v) lemongrass in coating formulation significantly (p < 0.05) decreased the firmness and sensory scores (taste, texture and overall acceptability) of fresh-cut pineapples. Therefore, the results indicate that an alginate-based edible coating formulation incorporated with 0.3% (w/v) lemongrass has potential to extend the shelf-life and maintain quality of fresh-cut pineapple.     

Effectiveness of submicron chitosan dispersions in controlling anthracnose and maintaining quality of dragon fruit

Conventional chitosan (CC) and submicron chitosan dispersions (SCD) were evaluated for the control of postharvest anthracnose and maintenance of quality of dragon fruit during storage at 10 ± 2 °C and 80 ± 5% RH for 28 days. All the chitosan treatments significantly reduced anthracnose symptoms, resulting in a reduction of disease development and thereby maintained the quality of fresh fruit for extended periods. SCD at 1.0% with 600 nm droplet size gave the best result in that it delayed the onset of disease and maintained the quality of dragon fruit for up to 28 days of storage. It can be concluded from the present investigation that SCD have potential to be used as an antifungal agent to control postharvest anthracnose and maintain quality of dragon fruit during storage.     

Control of postharvest diseases of fruit with an invert emulsion formulation of Trichoderma harzianum Rifai

Control of primary postharvest diseases caused by Rhizopus stolonifer, Botrytis cinerea, and Penicillium expansum on a variety of fresh fruit was evaluated with an invert emulsion formulation of Trichoderma harzianum. Diseases evaluated were quantified by the period of protection conferred by the antagonist and the diameter of decay lesions. Treatment of the various fruit species with formulated T. harzianum conidia in an invert emulsion significantly (P ≤ 0.05) reduced the mean lesion diameters of R. stolonifer on apple, pear, peach and strawberry, B. cinerea on grape, pear, strawberry, and kiwifruit, and P. expansum on grape, pear, and kiwifruit in comparison with the control treatment. Significant differences (P ≤ 0.05) were obtained in the mean percent reduction in lesion diameter caused by the same postharvest pathogens on the same fruit species due to the treatment with the formulated T. harzianum conidia relative to control treatment. The greatest mean percent reduction (86.7%) was obtained on apple fruit for the infection with R. stolonifer. Significant differences (P ≤ 0.05) were also obtained in the mean durations of the minimum protection period due to treatment with the formulated T. harzianum against the infection with the same postharvest pathogens on the same fruit species. The longest mean duration of the minimum protection period (up to 59 days) was obtained for unwounded apple fruit against the infection with R. stolonifer. Overall, the results indicate that the treatment with the invert emulsion formulation of T. harzianum protected fruit from infection by the primary postharvest pathogens of the fruit tested for up to 2 months and reduced the diameters of decay lesion up to 86% and is a promising treatment to prolong the postharvest shelf-life of fresh fruit.     

Interaction of temperature control deficiencies and atmosphere conditions during blueberry storage on quality outcomes

Southern hemisphere blueberry producers often export their products through extended supply chains to Northern hemisphere consumers. During extended storage, small variations in temperature or atmosphere concentrations may generate significant differences in final product quality. In addition, relatively short delays in establishing cool storage temperatures may contribute to quality loss. In these experiments a full factorial analysis was done of the effects of three cooling delays (0, 12 or 24 h at 10 °C), three atmosphere concentrations (air, 10% CO₂ + 2.5% O₂ and 10% CO₂ + 20% O₂) and two storage temperatures (0 °C and 4 °C) which were assessed for their impact on final quality, measured as weight loss, firmness and rot incidence. Two blueberry cultivars were studied: ‘Brigitta’, a highbush cultivar, and ‘Maru’, a rabbiteye. Delays in cooling had a small effect on final product weight, whereas variation in storage temperature and atmosphere during simulated transport influenced both firmness and rot incidence. Atmospheres with 10% CO₂ reduced decay incidence, particularly at low oxygen concentration (2.5% O₂), although the latter conditions tended to soften fruit. In order to achieve optimal postharvest storage for blueberries, minimising temperature variability in the supply chain is important, as is finding the potentially cultivar-specific optimal combination of high CO₂ and low O₂ concentration that results in simultaneously minimising rot incidence and induced softening.     

Postharvest quality of peeled prickly pear fruit treated with acetic acid and chitosan

White (Opuntia albicarpa) and red (Opuntia ficus-indica) prickly pears were peeled and submerged in chitosan solutions containing different concentrations of acetic acid (1.0 or 2.5%) to obtain ready-to-eat prickly pear products. Some physicochemical (pH, total soluble solids, color, weight loss, and firmness), antioxidant (phenolic compounds and antioxidant activity), microbiological (aerobic mesophile bacteria and yeasts plus molds), and sensory (color, firmness, aroma, flavor, and overall acceptance) characteristics were assessed during 16 d of storage at 4 ± 1 °C and 85 ± 5% of relative humidity. Chitosan coating containing 1.0% of acetic acid delayed weight loss, maintained firmness and color of white prickly pear during the storage time. Most of the sensory values for white prickly pear coated with chitosan containing 1.0 and 2.5% of acetic acid were higher than those obtained for uncoated fruit. Red prickly pear coated with chitosan with 2.5% acetic acid did not maintain its sensory quality throughout 16 d of storage. Chitosan coating with 1 and 2.5% acetic acid did not affect phenolics content and antioxidant activity in white prickly pears; however, an increase of these compounds was observed in red prickly pears. Microbe populations were unchanged in white prickly pears (<10 CFU g⁻¹) and slightly increased in red prickly pears (10–500 CFU g⁻¹) coated with chitosan during the entire storage time.     

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.     

Effects of electron-beam irradiation on blueberries inoculated with Escherichia coli and their nutritional quality and shelf life

Fresh blueberries have become a popular new functional food because of their remarkably high levels of antioxidant phytonutrients and health benefits. However, the potential prevalence of human pathogens on blueberries has become an increased concern because they are consumed fresh. Procedures effective in decontamination and extending shelf life without affecting fruit quality are needed. Electron-beam irradiation was applied to fresh blueberries at the doses ranging from 0.5 to 3.0 kGy and its effectiveness for inactivating Escherichia coli (E. coli) K-12 and extending shelf life were investigated. The decimal reduction dose, D₁₀ values, of E. coli in cultural medium and blueberries were 0.43 ± 0.01 kGy and 0.37 ± 0.015 kGy, respectively. Irradiation reduced bacteria inoculated on blueberries from 7.7 × 10⁸ CFU/g to 6 CFU/g at 3.13 kGy and decreased the decaying of blueberries stored at 4 °C up to 72% and at room temperature up to 70% at this dose. No significant effect on the total monomeric anthocyanins, antioxidant activity, and l-ascorbic acid content of blueberries was observed from irradiation at doses ≤3 kGy. However, significant decreases in the antioxidant activity and l-ascorbic acid content were found in both control and irradiated blueberries after storage at 4 °C for 7 and 15 d. Information obtained in this study indicates that low dose electron-beam irradiation is effective in reducing E. coli and extending shelf life while maintaining the antioxidant properties of blueberries.     

Carrageenan as an alternative coating for papaya (Carica papaya L. cv. Eksotika)

Edible coatings are gaining popularity compared to other types of packaging due to their more environmental friendly nature and ability to carry active ingredients. In this study, a two-factor central composite design (CCD) was used to optimize a carrageenan-based edible coating formulation for coating of ‘Eksotika’ papayas. The effect of a carrageenan-based [carrageenan (0.2–0.8%, w/v) and glycerol (0–1%, w/v)] coating on firmness and colour components (L, a and b values) of papaya was evaluated. From the optimization study, no significant (p > 0.05) lack of fit was found for the reduced model for all response variables (firmness, L, a and b values) tested. Coefficients of determination (R²) ranging from 0.767 to 0.952 were obtained for these responses. From the multiple response optimization analysis, a combination of 0.78% (w/v) carrageenan with 0.85% (w/v) glycerol for a carrageenan-based coating was predicted to give desirable effects for the response variables tested, with no significant (p > 0.05) differences between the experimental and predicted values.     

Edible coatings containing chitosan and moderate modified atmospheres maintain quality and enhance phytochemicals of carrot sticks

Carrot sticks are increasingly in demand as ready-to-eat products, with a major quality problem in the development of white discoloration. Modified atmosphere packaging (MAP) and edible coating have been proposed as postharvest treatments to maintain quality and prolong shelf-life. The combined application of an edible coating containing 5 mL L^?1 of chitosan under two different MAP conditions (10 kPa O₂ + 10 kPa CO₂ in Pack A and 2 kPa O₂ + 15–25 kPa CO₂ in Pack B) over 12 d at 4 °C was studied. Respiration rate, microbial and sensory qualities as well as the contents of vitamin C, carotenoids and phenolics of coated and uncoated carrot sticks were evaluated. The use of the edible coating containing chitosan preserved the overall visual quality and reduced surface whiteness during storage. Microbial populations were very low and not influenced by coating or MAP. Edible coating increased respiration rates of carrot sticks, although this was only noticeable in the package with the less permeable film (Pack B). Vitamin C and carotenoids decreased during storage particularly in coated carrot sticks. In contrast, the content of total phenolics markedly increased in coated carrot sticks stored under moderate O₂ and CO₂ levels, while it was controlled under low O₂ and high CO₂ levels. The combined application of edible coating containing chitosan and moderate O₂ and CO₂ levels maintained quality and enhanced phenolic content in carrot sticks.     

Methyl jasmonate induces resistance against Penicillium citrinum in Chinese bayberry by priming of defense responses

Methyl jasmonate (MeJA) can act as an activator of defense responses in plants against pathogenic infection. However, the mechanisms involved in the postharvest induction of resistance by MeJA in fruit are largely unknown. Thus, we investigated the effect of a postharvest MeJA treatment on disease resistance against Penicillium citrinum infection in Chinese bayberries and the possible mechanisms. The results indicated that treatment with 10 μmol L⁻¹ of MeJA significantly inhibited green mould rot caused by P. citrinum, with the decay incidence being 66.2% lower than that of the control fruit after storage at 1 °C for 8 d. Moreover, it is clear that MeJA triggers a priming mechanism in Chinese bayberries, since only the MeJA-treated fruit showed an enhanced capacity to augment defense responses upon challenge with the pathogen. These augmented responses included an H₂O₂ burst, enhanced protein levels of phenylalanine ammonia-lyase and chitinase, and accumulation of phenolic compounds, lignin and phytoalexin. Therefore, our results suggest that a postharvest MeJA treatment induces disease resistance against P. citrinum in Chinese bayberries by priming of defense responses.     

Postharvest litchi (Litchi chinensis Sonn.) quality preservation by Lactobacillus plantarum

The objective of this work was to preserve the postharvest quality of litchi cv Brewster by the application of Lactobacillus plantarum. A suspension of 1 × 10⁹ CFU/mL of the bacteria was sprayed on ripe litchis and then stored at 10 °C with 75% of relative humidity. Treated fruit exhibited a significantly higher Gram positive bacteria growth on the rind (4–5 log CFU/g) than that detected in control fruit (2.5–3.75 log CFU/g). This result was corroborated by observing a high population of lactobacilli in scanning electron micrographs and by measurement of the content of lactic acid produced. Treated fruit displayed significantly (α ≤ 0.05) reduced color losses as indicated by the higher L* and C* values in comparison with the untreated ones. Additionally, cyanidin-3-rutinoside and total anthocyanin contents supported the measured color retention, since the pericarp of fruit treated with Lb. plantarum showed a significantly higher concentration of pigments than those used as control. In addition, a high concentration of phenolic compounds was found in the rind of treated fruit.     

Effectiveness of postharvest treatment with chitosan and other resistance inducers in the control of storage decay of strawberry

This study compared the effectiveness of practical grade chitosan when used in solution with acetic, glutamic, formic and hydrochloric acids, and a water-soluble commercial chitosan formulation, in controlling postharvest diseases of strawberry. The commercial chitosan formulation and other resistance inducers based on benzothiadiazole, oligosaccharides, soybean lecithin, calcium and organic acids, and Abies sibirica and Urtica dioica extracts were also tested. The commercial chitosan formulation was as effective as the practical grade chitosan solutions in the control of gray mold and Rhizopus rot of strawberries immersed in these solutions and kept for 4 days at 20 ± 1 °C. Moreover, the treatment with commercial and experimental resistance inducers reduced gray mold, Rhizopus rot and blue mold of strawberries stored 7 days at 0 ± 1 °C and then exposed to 3 days shelf-life. The highest disease reduction was obtained with the commercial chitosan formulation, followed by benzothiadiazole, calcium and organic acids. The compounds that provided the best results in postharvest applications to control storage decay of strawberries, should be tested in further trials through preharvest treatments, applied at flowering and a few days before harvest.     

Chitosan applications pre- or postharvest prolong raspberry shelf-life quality

Raspberries are fruit with high metabolism that makes them very perishable, impairing their storage and shelf-life. Chitosan coatings have the potential to improve their postharvest life by reducing water loss, respiration rate and decay incidence. The purpose of this work was to study the effect of different concentrations of chitosan, applied pre- or postharvest, on the retention of quality attributes of fresh raspberries. The chitosan concentrations tested were 0 (control), 0.5, 1.0 or 2.0%. The postharvest treatment was applied immediately after harvest, dipping the fruit in the solutions for 5 min. The pre-harvest treatment was done with one hand-spray application per week for three weeks, starting when the fruit were just turning pink. In both experiments the fruit were stored at 0 °C and 90% RH. Pre- or postharvest use of chitosan at 1 or 2% was effective in maintaining titratable acidity and retarding respiration and ethylene production, weight loss and decay incidence. Application by both means resulted in the highest chitosan concentrations accelerating a reduction of ascorbic acid contents. Firmness was maintained only when the fruit were treated pre-harvest at 2%. Thus, application of chitosan at 1 or 2% postharvest and 2% pre-harvest was able to retain key raspberry quality attributes for 15 and 12 days, respectively.     

Control of postharvest grey mould (Botrytis cinerea Per.: Fr.) on strawberries by glucosinolate-derived allyl-isothiocyanate treatments

The vapours of allyl-isothiocyanate (AITC) were evaluated in in vitro and in vivo trials against Botrytis cinerea, a severe pathogen of strawberries. In in vitro trials AITC activity was assayed on conidial germination and mycelial growth of the fungus. The mycelium appeared less sensitive to AITC than conidia (EC₅₀ values of 1.35 mg L⁻¹ and 0.62 mg L⁻¹, respectively). In addition, AITC had a fungistatic effect against the pathogen, since the values of EC₅₀, for both parameters, increased by around 30% after AITC removal. In in vivo trials, ‘Tecla’ and ‘Monterey’ strawberries (spring-bearing and day-neutral cultivars, respectively) obtained from organic production and naturally infected by B. Cinerea, were exposed for 4 h in an atmosphere enriched by pure AITC or derived from defatted seed meals of Brassica carinata (0.1 mg L⁻¹, in a 0.1 m³ treatment cabinet). After 2 days at 0 °C and another 3–4 days at 20 °C, the fruit were evaluated for grey mould infections. The AITC treatment reduced the decay caused by the pathogen by over 47.4% up to 91.5%, significantly different from the untreated fruit. No significant differences were found between synthetic and glucosinolate-derived AITC. Residue analysis performed on fruit at the end of storage (7 d after treatment) showed values lower than 1 mg kg⁻¹. Total phenolic content and antioxidant capacity estimated in treated and untreated strawberries showed no significant difference between control and AITC treated fruit. Our results show it is possible to reduce the incidence of postharvest grey mould on strawberries with a treatment of AITC (0.1 mg L⁻¹) for 4 h, opening a potential application of biofumigation in the postharvest control of B. cinerea in strawberry.     

UV-B irradiation retards chlorophyll degradation in lime (Citrus latifolia Tan.) fruit

Peel yellowing is a major postharvest problem of lime fruit. Research was conducted to control peel yellowing by UV-B irradiation. Mature green lime fruit were irradiated with UV-B doses at 0 (control), 8.8, and 13.2 kJ m^?2 and then stored at 25 °C in darkness. UV-B treatment at 8.8 kJ m^?2 efficiently delayed the decrease of chlorophyll content. A high level of chlorophyllide a accumulated in mature green fruit and then gradually decreased with the progress of peel yellowing. The chlorophyllide a level was higher in 8.8 kJ m^?2 UV-B-treated fruit than it was in the controls. The pheophorbide a level declined in lime fruit treated with 8.8 kJ m^?2 UV-B, especially during the development of yellowing. In addition, the pheophytin a level increased by 8.8 kJ m^?2 UV-B treatment at the late period of storage. We concluded that UV-B treatment effectively suppressed chlorophyll degradation in mature green lime during storage, which suggests that UV-B irradiation is a usable method for prolonging the postharvest life of lime fruit.