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- Strategies to preserve postharvest quality of horticultural crops and superficial scald control: from diphenylamine antioxidant usage to more recent approachesPublication . Dias, Cindy; Amaro, A. L.; Salvador, Ângelo C.; Silvestre, Armando J.D.; Rocha, Sílvia M.; Isidoro, Nélson; Pintado, ManuelaHorticultural crops are vulnerable to several disorders, which affect their physiological and organoleptic quality. For about forty years, the control of physiological disorders (such as superficial scald) in horticultural crops, particularly in fruit, was achieved through the application of the antioxidant diphenylamine (DPA), usually combined with controlled atmosphere (CA) conditions. However, identification of DPA residues and metabolites in treated fruits, associated with thei toxicity, banned the use of this antioxidant in Europe. This triggered the urgent need for novel and, ideally, natural and sustainable alternatives, combined with adequate storage conditions to protect cultivars from harmful agents. This review systematizes the state-of-the-art DPA application on several fresh cultivars, such as apples, pears, and vegetables (potatoes, spinach, etc.), as well as the possible mechanisms of the action and effects of DPA, emphasizing its antioxidant properties. Alternative methods to DPA are also discussed, as well as respective effects and limitations. Recent research on scald development molecular pathways are highlighted to open new non-chemical strategies opportunities. This appraisal shows that most of the current solutions have not lead to satisfactory commercial results; thus, further research aimed to understand the mechanisms underlying postharvest disorders and to design sustainable and safe solutions to improve horticultural products storage is needed.
- Bioactive compounds in ready-to-eat rocket leaves as affected by oxygen partial pressure and storage time: a kinetic modellingPublication . Pereira, M. J.; Amaro, A. L.; Oliveira, A.; Pintado, M.Storage techniques, such as low temperature and modified atmosphere packaging, are efficient in keeping visual quality of ready-to-eat (RTE) products such as processed leafy vegetables throughout the supply chain, but studies on appearance often neglect the effect of different storage conditions on their nutritional properties. The effects of initial O2 partial pressure (20, 10, 5 and 2.5 kPa O2) in packages and storage time (14 d) on RTE rocket leaves on the bioactive compounds, phenolics, ascorbic acid, and antioxidant activity were determined. Kinetic models were applied to allow the assessment and prediction of the influence of initial partial pressure on nutritional composition. The results show that lowering package initial O2 partial pressure from 20 kPa to 5–10 kPa reduced the respiration rate by 53 and 38%, respectively. However, antioxidant activity and ascorbic acid content showed most effects with an initial O2 of 5 kPa. The kinetic parameters are relevant to help predict phytochemical changes during storage under different package O2 partial pressures. To obtain an overall quality, the application of intermediate atmospheres would be beneficial.