María José Zaro

Eggplant (Solanum melongena L.) is highly susceptible to chilling injury (CI) during cold storage, with severity being strongly influenced by fruit maturity stage. At the tissue level, the peel acts as the primary site of cold-stress metabolic responses. This study evaluated the effect of pre-storage glycine betaine treatment (GB, 10 mM) on CI in purple eggplant at baby (BB, low sensitivity) and commercial (CC, high sensitivity) maturity stages stored at 4 °C for 20 days, integrating the use of ATR-FTIR spectroscopy as a rapid, non-destructive tool to monitor quality in the fruit peel. Physiological traits including chilling injury index (CII) and fruit rigidity were integrated with peel-specific ATR-FTIR spectroscopy combined with chemometric analysis to describe structural and metabolic behavior. BB fruit showed higher tolerance to CI, reaching a CII 23% lower than CC after 20 d, along with greater rigidity retention. GB treatment was significantly effective in reducing CI in both maturity stages by decreasing CII by 23% for BB and 32% for CC fruit, and delaying symptom onset. FTIR analysis revealed that the main peel spectral changes during storage occurred in the amide–phenolic (1653–1515 cm⁻¹) and polysaccharide (~1017 cm⁻¹) regions. Control fruit showed progressive shifts in these regions indicating structural disorganization, while GB-treated fruit delayed and attenuated spectral changes. Chemometric analysis (OPLS-DA) clearly discriminated samples according to maturity stage, treatment, and storage time. Overall, the results demonstrate that chilling susceptibility is determined by maturity stage, that the GB treatment enhanced CI tolerance—especially in sensitive CC fruit—and that ATR-FTIR coupled with chemometrics provides an effective approach for rapid non-destructive monitoring of postharvest quality changes in eggplant during cold storage.

Eggplant is highly susceptible to chilling injury (CI) when stored at temperatures below 10 °C. This study evaluated the efficacy of glycine betaine (GB) as a pre-storage treatment to enhance chilling tolerance in eggplant, focusing on tissue-specific responses in the peel and flesh. GB concentrations of 0, 5, and 10 mM were tested, with 10 mM identified as the most effective in mitigating CI symptoms and weight loss. Subsequently, eggplants treated with 10 mM GB were stored for 21 days at 4 °C, followed by 2 days at 20 °C, to assess their physiological and biochemical properties. At the end of the storage period, GB treatment significantly reduced all CI-related indicators, including the CI index, weight loss, respiration rate, softening, flesh browning, electrolyte leakage, and malondialdehyde content, thereby extending shelf life by five days compared with untreated fruit. Principal component analysis revealed that severe CI in control fruit was associated with elevated levels of proline, endogenous GB, and unsaturated fatty acids (UFAs) in the peel, indicating that this outer tissue is the primary site of cold-stress responses in eggplant. Conversely, GB-treated fruit exhibited enhanced chilling tolerance characterized by reduced softening, greater antioxidant retention in both tissues, and maintenance of UFA levels in the flesh, while peel proline, GB, and fatty acid contents remained stable. Overall, our findings provide the first evidence that GB confers cold protection by modulating tissue-specific metabolic responses in eggplant peel and flesh, offering a simple and cost-effective strategy to extend shelf life.

Bell peppers (Capsicum annuum L.) are prone to chilling injury (CI) when stored at temperatures below 7 °C. Melatonin, a natural plant regulator, plays a critical role in defending against different pre- and post-harvest abiotic stresses, including those associated with cold storage. This study aimed to assess the effects of applying exogenous melatonin alone and in combination with a commercial wax on the CI tolerance, postharvest life, and potential biomarker search of red bell peppers. In the initial experiment, the effective melatonin concentration to reduce CI effects was determined. Peppers were sprayed with either distilled water (control) or a melatonin aqueous solution (M100 = 100 μM or M500 = 500 μM) and then stored for 33 d at 4 °C, followed by 2 d at 20 °C. The M500 treatment proved to be more effective in reducing fruit CI incidence (superficial scalds) and metabolic rate, while weight loss, softening, and color were comparable to the control. A second experiment assessed the potential synergistic effects of a combined melatonin and commercial wax treatment on pepper CI and quality. Fruits were sprayed with distilled water (control), melatonin (M500), commercial wax (Wax), or the combined treatment (Wax + M500) and stored for 28 d at 4 °C, followed by 2 d at 20 °C. The Wax + M500 was the most effective in significantly reducing the incidence of fruit CI symptoms and calyx fungal infection. Furthermore, this combined treatment enhanced fruit weight loss prevention compared with individual melatonin or wax treatment. Also, Wax + M500-treated peppers exhibited notable proline accumulation, indicative of a metabolic response counteracting the cold effects, resulting in better fruit stress acclimation. This treatment also preserved the peppers’ color and antioxidant capacity. In summary, these findings highlight the suitability of applying a combined Wax + M500 treatment as a highly effective strategy to enhance the CI tolerance of peppers and extend their postharvest life.

BACKGROUND: Vegetable grafting has been increasingly evaluated to improve preharvest tolerance to biotic and abiotic stresses. However, very few studies have identified rootstock–scion combinations able to improve fruit shelf life and reduce the susceptibility to postharvest disorders. Herein, a purple eggplant scion (cv. Monarca) was grafted onto a cold‐tolerant hybrid Solanum rootstock (‘Java’) and the changes in growth, quality, postharvest chilling tolerance, and antioxidant stability were evaluated.RESULTS: Eggplant grafting enhanced plant vigor and fruit growth rate, decreasing the time from set to harvest by 10–15%. Grafted eggplants had a thinner shape and lighter pulp color than the control. The rootstock–scion combination tested showed lower respiration (~60%), dry matter (~15–20%), and phenolic compounds contents (~15–20%) than eggplants from non‐grafted plants. Grafting markedly improved fruit performance during postharvest storage. Remarkably, grafted eggplants showed much higher tolerance to chilling injury than the control did, evidenced by a reduction of surface scalds along with decreased softening and pulp browning. The trend in antioxidants found at harvest time was reversed after cold storage due to enhanced stability (20% and 100% for pulp and peel respectively) in fruit from grafted plants.CONCLUSION: Purple eggplant (cv. Monarca) grafting onto ‘Java’ hybrid rootstock modulated fruit growth, quality at harvest, and increased fruit chilling injury tolerance during storage. Grafting may be a bona fide strategy to induce phenotypic traits able to improve vegetable postharvest performance. © 2021 Society of Chemical Industry.

In this work, we selected a short UV-C treatment for fresh-cut carambola and assessed its efficacy in supplementing the benefits of low temperature storage. UV-C treated (6.0, 10.0, and 12.5 kJ m⁻²) carambola slices showed reduced deterioration compared to control fruit. Treatment with a dose of 12.5 kJ m⁻²UV-C was more effective in maintaining quality and was selected for subsequent experiments evaluating the combination of UV-C and refrigeration on fruit storability and physical, chemical, and microbiological properties. Short UV-C exposure reduced weight loss and electrolyte leakage. UV-C treated carambola slices presented higher phenolic antioxidants than control after 21 d at 4°C and showed no alterations in soluble solids or titratable acidity. UV-C exposure also reduced the counts of molds, yeast, and aerobic mesophilic bacteria. UV-C treated fruit showed a fresh-like appearance even after 21 d as opposed to control carambola which presented spoilage and extensive browning symptoms. The reduction of fruit browning in UV-C treated fruit was not due to reduction in phenylalanine-ammonia lyase (PAL) and/or peroxidase (POD), but rather through polyphenol oxidase (PPO) inhibition and improved maintenance of tissue integrity.

Three Andean fruits naranjilla (Solanum quitoenseLam.), uvilla (Physalis peruvianaL.), and mortiño (Vaccinium floribundumKunth) were subjected to prestorage UV-C treatments (0, 8, or 12.5 kJ m⁻²) and evaluated weekly to select the most suitable dose for fruit quality maintenance during storage (21 days at 6°C). The highest dose retains quality through lower deterioration index for all three fruits and was selected to further analyze the effects on physicochemical and antioxidant properties during storage. UV-C exposure delayed softening in naranjilla and increased soluble solid content in uvilla. UV-C also improved the maintenance of antioxidant capacity (AC) in mortiño and uvilla. Overall, results indicate that short prestorage UV-C exposure may be an effective nonchemical approach to supplement low temperature storage, maintain quality, and extend the postharvest life of Andean naranjilla, uvilla, and mortiño fruit.

During the treatment of tuberculosis infection, oxidative stress due to anti-tubercular drugs may result in tissue inflammation. It was suggested that treatment with antioxidant drugs could be beneficial as an adjunct to anti-tuberculosis drug therapy. Recently our group has shown that several C-glycosides are inhibitors of Mycobacterium tuberculosis β-carbonic anhydrases (CAs, EC 4.2.1.1). In an effort to develop novel chemotherapeutic agents against tuberculosis, the anti-tubercular and antioxidant activities of a series of C-glycosides containing the phenol or the methoxyaryl moiety were studied. Many compounds showed inhibition of growth of M. tuberculosis H₃₇Rv strain and good antioxidant ability. A glycomimetic incorporating the 3-hydroxyphenyl moiety showed the best activity profile and therefore this functionality represents lead for the development of novel anti-tubercular agents with dual mechanisms of action.