Mouna Ben Amara

Postharvest fungal decay and physiological deterioration are major causes of citrus fruit losses during storage and distribution. This study evaluated selected postharvest management strategies for maintaining fruit quality and controlling fungal decay in ‘Maltaise’ and ‘Valencia Late’ oranges in two separate experiments conducted during winter and late spring to early summer, respectively, under contrasting storage conditions. Treatments included Scholar® (fludioxonil), clove and cinnamon essential oils (EOs), chitosan, ammonium bicarbonate, and Polyversum®, with distilled-water-treated and untreated fruit serving as controls. ‘Maltaise’ oranges were stored at 5 °C for 35 days followed by 7 days at approximately 18 °C, whereas ‘Valencia Late’ oranges were stored at 5 °C for 58 days followed by 24 days at 26–31 °C. Fruit deterioration was evaluated through weight loss, decay incidence, McKinney’s disease severity index, and a composite loss index (CLI), complemented by principal component analysis (PCA) and hierarchical cluster analysis (HCA). In ‘Maltaise’, Scholar® provided the strongest protection during cold storage, with decay incidence and disease severity index both at 0.7%, and maintained relatively low decay incidence (5.3%) during subsequent shelf life. In contrast, decay incidence reached 19.3% with clove EO, 20.7% with Polyversum®, and 22.0% in distilled-water-treated fruit. Polyversum® also produced an undesirable white, powdery residue on the peel. In ‘Valencia Late’, weight loss after cold storage ranged from 4.3% in distilled-water-treated fruit to 11.4% in combined-treatment groups, while decay incidence remained low (0–6.7%). Acidification of chitosan with acetic acid and its combination with clove EO provided no additional protection compared with the individual treatment. The relative performance of clove and cinnamon EOs differed between experimental conditions, indicating that their effectiveness was context-dependent. Notably, untreated fruit exhibited satisfactory overall quality and performed similarly to or better than Scholar® in the CLI assessments, highlighting the importance of initial fruit selection. PCA and HCA further revealed distinct deterioration profiles associated with treatment and storage combinations. Overall, the findings support an integrated, preventive approach to citrus postharvest management, prioritizing careful pre-storage sorting and appropriate storage conditions, with additional treatments applied selectively according to decay risk and storage requirements. This strategy could help maintain fruit quality while reducing unnecessary postharvest inputs.

Pre-storage fruit injuries are a major yet often underestimated cause of postharvest losses in apples, particularly during prolonged cold storage. This study evaluated the impact of minor pre-storage injuries on fruit deterioration and assessed the effectiveness of ammonium bicarbonate (2%) and clove bud essential oil (0.2%) as eco-friendly postharvest treatments compared with the fungicide fludioxonil (Scholar). Fresh red and yellow apples were classified as either intact fruit or fruit bearing minor injuries affecting less than 2% of the surface area (approximately 2 mm lesions). Treatments were applied by spraying before storage at 5 °C for six months, followed by 10 days of shelf life at 20 °C. Minor injuries significantly increased postharvest decay, weight loss, and quality deterioration in both cultivars. Injured yellow apples exhibited decay incidence of 17–24% and disease severity of 10.5–17.8%, whereas the more susceptible red apples showed decay incidence of 44.6–60% and disease severity of up to 50%. In contrast, non-injured fruit maintained better physicochemical quality and generally exhibited less than 5% decay incidence. Responses to storage and treatments differed between cultivars. Ammonium bicarbonate effectively reduced decay and helped maintain firmness in yellow apples, providing protection comparable to that of fludioxonil, whereas Scholar was the most effective treatment for reducing decay in red apples. Clove essential oil reduced disease development in non-injured fruit but showed limited effects on firmness preservation. The residual activity of fludioxonil remained detectable after prolonged storage, as demonstrated by inoculation assays performed after storage. The results demonstrate that fruit integrity at harvest is a critical determinant of successful long-term storage and that the benefits of postharvest treatments are substantially reduced when fruit are mechanically injured. Preventive treatment of uninjured fruit with ammonium bicarbonate or Scholar can significantly reduce postharvest losses, while careful handling and sorting to eliminate injured fruit remain essential components of sustainable apple storage management.

Pre-storage fruit injuries are a major yet often underestimated cause of postharvest losses in apples, particularly during prolonged cold storage. This study evaluated the impact of minor pre-storage injuries on fruit deterioration and assessed the effectiveness of ammonium bicarbonate (2%) and clove bud essential oil (0.2%) as eco-friendly postharvest treatments compared with the fungicide fludioxonil (Scholar). Fresh red and yellow apples were classified as either intact fruit or fruit bearing minor injuries affecting less than 2% of the surface area (approximately 2 mm lesions). Treatments were applied by spraying before storage at 5°C for six months, followed by 10 days of shelf life at 20°C. Minor injuries significantly increased postharvest decay, weight loss, and quality deterioration in both cultivars. Injured yellow apples exhibited decay incidence of 17–24% and disease severity of 10.5–17.8%, whereas the more susceptible red apples showed decay incidence of 44.6–60% and disease severity of up to 50%. In contrast, non-injured fruit maintained better physicochemical quality and generally exhibited less than 5% decay incidence. Responses to storage and treatments differed between cultivars. Ammonium bicarbonate effectively reduced decay and helped maintain firmness in yellow apples, providing protection comparable to that of fludioxonil, whereas Scholar was the most effective treatment for reducing decay in red apples. Clove essential oil reduced disease development in non-injured fruit but showed limited effects on firmness preservation. The residual activity of fludioxonil remained detectable after prolonged storage, as demonstrated by inoculation assays performed after storage. The results demonstrate that fruit integrity at harvest is a critical determinant of successful long-term storage and that the benefits of postharvest treatments are substantially reduced when fruit are mechanically injured. Preventive treatment of uninjured fruit with ammonium bicarbonate or Scholar can significantly reduce postharvest losses, while careful handling and sorting to eliminate injured fruit remain essential components of sustainable apple storage management.

Fruits are susceptible to a diverse range of postharvest rots that can reduce quality if preventive measures are not taken in time. In this study, samples of orange cv. 'Maltaise' and apple cvs. ‘Golden Delicious' and 'Richared' were sorted without infection or injury, treated or not with sodium metabisulfite (SMB), then placed in cold storage for 20, 42 or 59-61 days, followed by a shelf life of 6 or 15 days. The degree of fruit infection, weight loss and physicochemical characteristics were analyzed at each storage period. Our results indicate that adequate postharvest storage depends on the type of fruit, the duration of cold storage and shelf life. The heat map grouped 'Richared' apples close to its fresh state, without developing rot or perceptible weight loss for 60 days at low temperature (6°C) and 15 days of shelf life. These red apples performed better during storage than the “Golden”, especially in terms of storability and total flavonoids. Apples of 'Golden' showed better storage stability than 'Maltaise', which could be stored properly for up to 20 days at 6°C, followed by a 15-day shelf life, regardless of treatment with sodium metabisulfite. The longer the oranges were stored, the greater the risk of infection and the physicochemical properties, in this case flavonoids, decreased. The chemical criteria (TSS, pH) of apples and oranges were not affected by soaking in SMB, being similar to that of untreated fruit. However, treating fruit with SMB is regarded as unlikely due to its low effectiveness in preventing fruit decay during long-term storage. Cluster analysis showed that total polyphenols were linked to poor storability, while flavonoids, hardness and TSS were clustered with better storability. This suggests that flavonoids may be a more reliable indicator of storage suitability than total polyphenols.

This study evaluates the efficacy of the salts sodium metabisulfite (SMB), ammonium bicarbonate, sodium bicarbonate, and potassium dihydrogen orthophosphate first in vitro against the main postharvest fruit rot fungi, Alternaria alternata, Botrytis cinerea, Penicillium italicum, and Penicillium digitatum. Results showed that 0.2% SMB completely inhibited the mycelium growth of the fungal species. Ammonium bicarbonate and sodium bicarbonate were less effective at 0.2% in inhibiting mycelial growth, ranging from 57.6% to 77.6%. The least effective was potassium dihydrogen orthophosphate. Experiments were also performed in vivo on wounded apples inoculated with the most pathogenic fungus, B. cinerea, and treated with SMB at concentrations of 0.2, 0.5, 1, 2, and 3%, both preventively and curatively. Results based on the decay size showed that SMB, when used as a preventive treatment, had a reduced efficacy, even with the highest concentration. However, this salt proved to be very effective at 0.5% in curative treatment since the decay was completely blocked. Our results suggest that the appropriate concentration of SMB for post-harvest treatment is 0.5% as a curative treatment. On the other hand, the 1% dose induced the onset of phytotoxicity around the wound. To assess the extent of the phytotoxicity reaction, higher concentrations of 1–4% SMB were applied to wounded fruit. Apples and oranges were inoculated or not with B. cinerea and P. digitatum, respectively. Doses of 1–4% induced phytotoxicity in the form of a discolored ring surrounding the wound on the epidermis of the fruit; this phytotoxicity enlarged as the concentration of SMB increased. The phytotoxic features were similar on apples and oranges. The methodological procedure made it possible to carry out a quantitative assessment of SMB phytotoxicity. This method is proposed as an easy-to-use technique for quantitatively estimating the phytotoxicity of antifungal compounds on post-harvest fruit.

This study evaluates the efficacy of the salts, sodium metabisulfite (SMB), ammonium bicarbonate, sodium bicarbonate and potassium dihydrogen orthophosphate first in vitro against the main postharvest fruit rot fungi, Alternaria alternata, Botrytis cinerea, Penicillium italicum and Penicillium digitatum. Results showed that 0.2% SMB completely inhibited mycelium growth of the fungal species. Ammonium bicarbonate and sodium bicarbonate were less effective at 0.2% in inhibiting mycelial growth, ranging from 57.6% to 77.6%. The least effective was potassium dihydrogen or-thophosphate. Experiments were also performed in vivo on wounded apples inoculated with the most pathogenic fungus, B. cinerea, and treated with SMB at concentrations of 0.2, 0.5, 1, 2 and 3%, both preventively and curatively. Results based on the decay size showed that SMB, when used as a preventive treatment, had a reduced efficacy, even with the highest concentration. However, this salt proved to be very effective at 0.5% in curative treatment, since the decay was completely blocked. Our results suggest that the appropriate concentration of SMB for post-harvest treatment is 0.5% as a curative treatment. On the other hand, the 1% dose induced the onset of phytotoxicity around the wound. To assess the extent of phytotoxicity reaction, higher concentrations of 1-4% SMB were applied to wounded fruit. Apples and oranges were inoculated or not with B. cinerea and P. digitatum respectively. Doses of 1- 4% induced phytotoxicity in the form of a discoloured ring surrounding the wound on the epidermis of the fruit; this phytotoxicity enlarged as the concentration of SMB increased. The phytotoxic features were similar on apples and oranges. The methodological procedure made it possible to carry out a quantitative assess-ment of SMB phytotoxicity. This method is proposed as an easy-to-use technique for quantitatively estimating the phytotoxicity of antifungal compounds on post-harvest fruit.

Maintaining the cold chain during long‐term storage is important for the preservation of fresh food quality. Arils are usually extracted from freshly harvested pomegranates or after a short storage period. Nevertheless, pomegranate fruit may be stored for several weeks before being marketed as ready‐to‐eat arils (REA). In this study, the effect of different postharvest storage periods (30, 45, and 60 days) and temperatures (2 and 6°C) on quality of arils extracted immediately after each storage period and then after 10 days shelf‐life were investigated. fruit storage period (FSP) affected significantly total phenols, antioxidant activity, and vitamin C content of REA immediately after extraction and after 10 days shelf‐life. Color, anthocyanins, and organic acids of REA varied significantly with storage period mainly after shelf‐life. The highest changes were observed after 60 days of FSP. Generally, storage temperature has shown no effect on bioactive properties and minimal influence after the aril shelf‐life period. Sensory and volatiles changes were affected by storage temperature but most especially by long storage duration. Thus, the aroma profile was markedly separated in heatmap by storage time and temperature. Similar aroma profiles for REA extracted immediately after each storage period or from freshly harvested fruit were distinguished. However, changes were important after shelf‐life for stored fruit at 6°C, with more abundance of terpenes such as (Z)‐β‐farnesene, (E)‐α‐bergamotene, and α‐pinene. The results obtained showed that, minor changes at both storage temperatures on aril were registered, also long‐term cold storage determines the final eating quality after shelf‐life. Practical applications Ready‐to‐eat arils quality is generally affected by several postharvest treatments and conditions. This study used a combination of storage temperatures and duration of “Gabsi” pomegranate fruit to determine the quality of ready aril after shelf‐life. Results of aril sensory analysis showed that overall flavor and appearance were highly rated in aril when fruit were stored for 2 months at 2°C. Similarly, results of instrumental measurements showed that fruit could be stored for 2 months at 2°C without significant reductions in compounds of benefit to health and aril color. Storing fruit for 60 days at 6°C led to a reduction in overall quality and changes in the aroma profile of REA. The outcomes of this study suggest that a storage period of 2 months at 2°C is recommended for REA use to maintain sensory quality and minimize reductions in volatile aroma components.