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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.
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Fresh-cut produce have become widely popular, increasing vegetable consumption in many parts of the word. However, they are more perishable than unprocessed fresh vegetables, requiring cold storage to preserve their quality and palatability. In addition to cold storage, UV radiation has been used experimentally to try to increase nutritional quality and postharvest shelf life, revealing increased antioxidant levels in some fruits and vegetables, including orange carrots. Carrot is one of the main whole and fresh-cut vegetables worldwide. In addition to orange carrots, other root color phenotypes (e.g., purple, yellow, red) are becoming increasingly popular in some markets. The effect of the UV radiation and cold storage has not been explored in these root phenotypes. This study investigated the effect of postharvest UV-C radiation in whole and fresh-cut (sliced and shredded) roots of two purple, one yellow, and one orange-rooted cultivar, with regard to changes in concentration of total phenolics (TP) and hydroxycinnamic acids (HA), chlorogenic acid (CGA), total and individual anthocyanins, antioxidant capacity (by DPPH and ABTS), and superficial color appearance, monitoring such changes during cold storage. Results revealed that the UV-C radiation, the fresh-cut processing, and the cold storage influenced the content of antioxidant compounds and activities to varying extents, depending on the carrot cultivar, the degree of processing, and the phytochemical compound analyzed. UV-C radiation increased antioxidant capacity up to 2.1, 3.8, 2.5-folds; TP up to 2.0, 2.2, and 2.1-folds; and CGA up to 3.2, 6.6, and 2.5-folds, relative to UV-C untreated controls, for orange, yellow, and purple carrots, respectively. Anthocyanin levels were not significantly modified by the UV-C in both purple carrots evaluated. A moderate increase in tissue browning was found in some fresh-cut processed UV-C treated samples of yellow and purple but not orange roots. These data suggest variable potential for increasing functional value by UV-C radiation in different carrot root colors.
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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.
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Solanum melongena , Antioxidantes/química , Frutas/química , Fenóis/análiseRESUMO
ABSTRACT: Artichoke (AF), eggplant (EF) and tomato (TF) flour were used as nutritional ingredients for wheat dough. A replacement of wheat flour with 5 or 10% of these vegetable flour was performed. Hydration properties (equilibrium adsorption isotherms, solvent retention capacity), capacity of blends for dough development (farinographic assay) and the proximal composition of flours were evaluated. Samples with high content of soluble sugar and low of insoluble fiber (EF and TF) presented higher equilibrium water sorption at 20 °C and 40 °C, at aw > 0.5. The solvent retention capacity of wheat-vegetable flour blends increased mainly at higher levels of replacement (10%) and with samples of artichoke and eggplant. The highest and the lowest stable dough with 10% of replacement was obtained with AF and EF, respectively. Water sorption and absorption parameters should be previously determined so as to obtain the optimum dough structure that lead to a high technological quality bread.
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Eggplant (Solanum melongena L.) is the third solanaceous of horticultural importance in the world, after potato and tomato. In the agricultural production of this vegetable, there are post-harvest losses and waste generation. Reduction of these inconveniences can be avoided by obtaining ingredients with high nutritional value for food processing, as breadmaking. Changes in wheat dough and bread quality due to the incorporation of eggplant flour were studied. Different levels (5, 7.5, 10%) of replacement with flour from Large eggplant were analysed. The optimum level of eggplant flour (7.5%) was used for comparison technological performance of eggplant-wheat breads elaborated with flour from eggplants of different size: small size eggplant (Baby, BE) and large size eggplant (Large, LE). Dough was characterized through farinographic (water absorption, development time, stability, softening degree) and fermentation parameters (maximum volume of fermented dough, fermentation time). Technological quality (specific volume, hardness, elasticity, number of crumb alveolus, colour of crust and crumb) and sensory analysis of breads were evaluated. Proximal composition and antioxidant activity of flour and breads were studied. Water absorption, development time and softening degree increased, while bread volume, elasticity and the area occupied by alveoli decreased with the presence of eggplant flour. Breads also became darker. Breads with 7.5% of BE, presented a harder crumb with lower luminosity than those with LE. Both type of breads were well accepted by consumers; nevertheless, BE was the bread that contains higher amount of compounds with antioxidant activity and therefore it is recommended for formulation of functional breads.
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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 ß-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.
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Antioxidantes/farmacologia , Antituberculosos/farmacologia , Inibidores da Anidrase Carbônica/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Testes de Sensibilidade MicrobianaRESUMO
UNLABELLED: The objective of this work was to select a Ultraviolet-C (UV-C) treatment for fresh-cut mature green bell pepper, and to evaluate the effect of its combination with refrigeration on quality maintenance. Bell pepper sticks were treated with 0, 3, 10, or 20 kJ/m² UV-C in the outer (O), inner (I), or both sides of the pericarp (I/O) and stored for 8 d at 10 °C. During the first 5 d of storage, all UV-C treatments reduced deterioration as compared to the control. The treatment with 20 kJ/m² I/O was the most effective to reduce deterioration, and was used for further evaluations. In a second group of experiments, mature green bell pepper sticks were treated with 20 kJ/m² I/O, stored at 5 °C for 7 or 12 d and assessed for physical and chemical analysis, and microbiological quality. UV-C-treated fruit showed lower exudates and shriveling than the control. UV exposure also reduced decay, tissue damage, and electrolyte leakage. After 12 d at 5 °C, UV-C irradiated peppers remained firmer and had higher resistance to deformation than the control. The UV-C treatments also reduced weight loss and pectin solubilization. UV-C exposure decreased the counts of mesophile bacteria and molds, and did not affect acidity or sugars. UV-C-treated fruit stored for 0 or 7 d at 5 °C did not show major differences in antioxidants from the control as measured against DPPH(â¢) or ABTS(â¢)⺠radicals. Results suggest that UV-C exposure is useful to maintain quality of refrigerated fresh-cut green pepper. PRACTICAL APPLICATION: Exposure to UV-C radiation before packing and refrigeration could be a useful nonchemical alternative to maintain quality and reduce postharvest losses in the fresh-cut industry.
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Capsicum/efeitos da radiação , Fast Foods/efeitos da radiação , Irradiação de Alimentos/métodos , Embalagem de Alimentos , Armazenamento de Alimentos , Frutas/efeitos da radiação , Raios Ultravioleta , Antioxidantes/análise , Capsicum/crescimento & desenvolvimento , Capsicum/microbiologia , Fenômenos Químicos , Carboidratos da Dieta/análise , Relação Dose-Resposta à Radiação , Eletrólitos/análise , Fast Foods/análise , Fast Foods/microbiologia , Frutas/crescimento & desenvolvimento , Frutas/microbiologia , Fungos/crescimento & desenvolvimento , Fungos/efeitos da radiação , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Negativas/efeitos da radiação , Bactérias Gram-Positivas/crescimento & desenvolvimento , Bactérias Gram-Positivas/efeitos da radiação , Concentração de Íons de Hidrogênio , Fenômenos Mecânicos , Pectinas/análise , Pectinas/química , Controle de Qualidade , SolubilidadeRESUMO
We evaluated the effect of short-term gaseous ozone treatment (10 microL/L; 10 min) on tomato fruit quality and cell wall degradation. The treatments did not modify fruit color, sugar content, acidity, or antioxidant capacity but reduced fruit damage and weight loss and induced the accumulation of phenolic compounds. In addition, softening was delayed in ozone-treated fruit. Cell wall analysis showed that exposure to ozone decreased pectin but not hemicellulose solubilization. Polyuronide depolymerization was also reduced in ozone-treated fruit. While the treatments did not alter the activity of the pectin-degrading enzymes polygalacturonase (PG) and beta-Galactosidase (beta-Gal), a clear decrease in pectin methyl esterase (PME) was found. Results show that short-term ozone treatments might be useful to reduce fruit damage and excessive softening, two of the main factors limiting tomato postharvest life, without negatively affecting other quality attributes. The impact of the treatments on fruit softening might be associated with reduced disassembly (solubilization and depolymerization) of pectic polysaccharides.