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- The impact of plant-based coatings in “ROCHA” pear preservation during cold storage: a metabolomic approachPublication . Fonseca, Alexandre M. A.; Dias, Cindy; Amaro, Ana L.; Isidoro, Nélson; Pintado, Manuela; Silvestre, Armando J. D.; Rocha, Sílvia M.Although new storage technologies have been emerging in recent years, preservation of pear (Pyrus communis L.) remains a challenge for suppliers. Maintenance of desired organoleptic properties throughout cold storage using non-chemical strategies has been investigated and the use of edible coatings has shown potential to delay fruit quality deterioration during cold storage. Thus, the objective of this study is to evaluate the impact of pectin coatings including plant extracts, in “Rocha” pear (Pyrus communis L. cv. Rocha) preservation. A four-month pilot scale assay was performed in both dynamic controlled atmosphere (DCA) (−0.5 °C, 0.5% O2, and 0.4% CO2) and normal atmospheric (NA) conditions (2 °C). For each storage condition, the following three coatings were tested: pectin (3% w/v) (PCT), pectin (3% w/v) + strawberry tree leaves extract (9.5 mg/mL) (CT1), and pectin (3% w/v) + apple pomace extract (16 mg/mL) (CT2). Volatile compounds, potentially related to aroma or ripening status of “Rocha” pear, were monitored alongside with conjugated trienols (CTs) and maturity parameters. The combination of DCA conditions and the application of pectin coatings were able to reduce the release of Rocha pear volatiles associated with ripening status, (particularly esters and sesquiterpenes), as well as reduce CTs, which could contribute to the preservation of Rocha pear for longer periods.
- 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.
- Impact of food matrix components on nutritional and functional properties of fruit-based productsPublication . Oliveira, Ana; Amaro, Ana L; Pintado, ManuelaNowadays, worldwide consumers seek delightful and appealing foods that are simultaneously safer, nutritional and healthier. Fruit-based products are largely consumed due to, in part, the consumer’s perception of these products as healthy and convenient perceived as similar or even with better health benefits than the raw fruits that originated them. However, it is of paramount importance to understand the impact of the food matrix components on nutritional and functional properties of fruit-based products. Isolated compounds, or fruit extracts are used more often than food products in interaction studies. These approaches do not consider the interferences of food matrix components and/or the impacts of food processing on bioactivity and bioaccessibility of the active compounds. In fact, the bioaccessibility of bioactive compounds can be different in diverse food matrices and this review aims to provide an integrated approach to the field of matrix interactions.
- 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.
- Multitrait analysis of fresh-cut cantaloupe melon enables discrimination between storage times and temperatures and identifies potential markers for quality assessmentsPublication . Amaro, Ana L.; Spadafora, Natasha D.; Pereira, Maria J.; Dhorajiwala, Rakhee; Herbert, Robert J.; Muller, Carsten T.; Rogers, Hilary J.; Pintado, ManuelaFresh-cut cantaloupe melon is valued for its aroma but is highly perishable. Temperature of storage (typically 0-5°C) is critical for maintaining fresh-cut melon quality, but often reaches 10°C during transportation and in retail outlets. A comparison amongst 0, 5 and 10°C storage temperatures for fresh-cut melon over 14days reveals that storage at 0°C is optimal for avoiding increases in microbial load and loss of vitamin C especially at later time points. However, higher temperatures maintain better the balance of esters (acetate versus non-acetate) and phenolic content. The whole volatile organic compound (VOC) profile can be used to discriminate both time and temperature effects especially at earlier time points. Potential VOC markers for changes in vitamin C from day 0 to day 6 of storage (3-methyl butane nitrile) and temperature (limonene) are identified through a multi-trait analysis.
- Impact of different calcium dips and solution pH on quality of ready-to-eat baby-leaf spinachPublication . Oliveira, Ana L.S.; Amaro, Ana L.; Sain, Jason de; Pintado, M. E.The effect of calcium application and solution pH on ready-to-eat (RTE) baby-leaf spinach (Spinacia oleracea L.) texture and structure preservation was studied. Spinach leaves were treated with calcium chloride, calcium lactate and calcium propionate, at two different pH conditions (5 and 7), packaged and stored for 7 days at 5 C. After 24 h, the leaves crispness increased 49 and 29% for leaves treated with calcium chloride and lactate at pH 5 and the elasticity increased 100% after calcium propionate treatment at pH 7. During spinach shelf-life, the tissue flexibility decreased (20–60%) for all calcium treatments at pH 5 and 7 while tissue crispiness increased (7–40%) only for calcium treatments under pH 7. The electrolyte leakage increased throughout storage and was higher for all calcium treated samples when compared with controls. The chlorophyll content slightly decreased (12%) by the end of product shelf-life and did not differ according the calcium treatments. Total vitamin C content was lower in leaves treated with calcium chloride at pH 5 (31%) and pH 7 (19%) while the remaining treatments did not affect vitamin C content. The different calcium additives tested for potential texture quality maintenance did not provide the expected benefits on baby spinach leaves but increasing solution pH from 5 to 7 lead to an increased firmness by the end of shelf-life.
- Fresh-cut melon quality during storage: an NMR study of water transverse relaxation timePublication . Fundo, Joana F.; Amaro, Ana L.; Madureira, Ana Raquel; Carvalho, Alexandra; Feio, Gabriel; Silva, Cristina L. M.; Quintas, MafaldaMolecular mobility is a fundamental parameter which reflects the dynamic properties of food components and contributes to food degradation reactions comprehension. Fresh-cut fruits have become an important food market segment. However, processing of fruits promotes faster its physiological deterioration, biochemical changes and microbial degradation. The purpose of this work was to use NMR methodology as a tool to evaluate fresh-cut fruit quality, during storage at refrigerated conditions. The fresh-cut melon transverse relaxation time (T2) was measured for a period of 7 days of storage at 5 °C. The relationship between the obtained values, microstructure and quality parameters was investigated. In general, results show the existence of one class of water fluidity in the system, the one present in cells after processing. T2, a measure of this fluidity, is affected by the processing and storage time. Also, it is possible to find a close relationships between T2 and quality parameters of total colour difference (TCD), firmness and aw. As T2 increases TCD also increases, while firmness and aw decrease. These results highlight the usefulness of NMR methodology application in food science.