Browsing by Author "Pintado, Manuela"
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- Cold storage demand for Rocha pear ripening: A comparison between a shorter and a longer cold periodPublication . Dias, Cindy; Ribeiro, Tânia; Rodrigues, Ana Cristina; Ferrante, António; Vasconcelos, Marta W.; Pintado, Manuela'Rocha' pear is a cultivar that when harvested at the recommended maturity stage (physiological condition that allows resisting to prolong cold storage), requires chilling exposure after harvest, to induce an autonomously ripening appreciated by the consumer. Fruit were stored immediately after harvest, for 6 d (batch 1) or 26 d (batch 2), in normal cold atmosphere storage, to further our understanding of 'Rocha' pear ripening under different short cold storage durations. The ripening events were then monitored at 0, 3, 7, and 10 d of shelf-life at room temperature (± 20 °C) through physicochemical and biochemical changes, including firmness, soluble sugars, malic acid, esters profile, and ethylene metabolism (1-aminocyclopropane-1-carboxylic acid (ACC) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO)). We found that ripening behaviour upon rewarming from both cold storage periods was similar, with fruit ripening with a typical pattern of ethylene production and respiration rates concomitant with a higher ACO activity. Soluble sugar and esters emission were not influenced by cold storage duration, but interestingly butyl acetate levels were significantly higher on pear, which was cold stored for 26 d Our data provide more novel information about Rocha' pear's ripening physiology, indicating for the first time that approximately one week of chilling temperature is enough to promote ripening rate processes. Such knowledge could be an asset to the efficient management of 'Rocha' pear storage.
- Improving the ripening process after 1-MCP application: Implications and strategiesPublication . Dias, Cindy; Ribeiro, Tânia; Rodrigues, Ana Cristina; Ferrante, António; Vasconcelos, Marta W.; Pintado, ManuelaBackground: Consumers’ lifestyles demand high-quality products, requesting adequate fruit storage. Management of ethylene production is of paramount importance when planning postharvest storage, since this phytohormone is the key molecule behind the ripening and senescence process. Cold storage combined with 1-MCP has been one of the most applied postharvest treatments to extend the shelf-life of several fruit. However, 1-MCP is a potent inhibitor of ethylene action, leading frequently to the blockage of ripening denominated as ‘evergreen’ effect. Scope and approach: Ethylene biosynthesis and perception pathway are described, as well as a critical review on 1-MCP inhibitory mechanisms. Technologies used to induce postharvest ripening after 1-MCP application are described with special attention to the latest and most significant published works. The most relevant 1-MCP reversion strategies are discussed, aiming to develop more innovative and effective approaches for stimulating ripening. Finally, the importance of tailoring treatments to specific cultivars is discussed, using pear as a case study. Key findings and conclusions: Optimizing temperature and applying exogenous ethylene have been the main methods to reverse the effect of 1-MCP. Also, treatment with other phytohormones has shown promising results. However, the strategies effectiveness is dependent on the cultivar, time of application, and concentration of the applied compound. Also, since 1-MCP binds irreversibly to the ethylene receptor, the biosynthesis of new receptors may reverse the ‘evergreen’ behaviour. Therefore, attempts should be made to develop strategies according to each cultivar and their capacity to stimulate the expression of ethylene genes both related to its biosynthesis and perception.
- In Situ Forming Silk Sericin-Based Hydrogel: A Novel Wound Healing BiomaterialPublication . Baptista-Silva, Sara; Borges, Sandra; Costa-Pinto, Ana Rita; Costa, Raquel; Amorim, Manuela; Dias, Juliana R.; Ramos, Óscar; Alves, Paulo; Granja, Pedro Lopes; Soares, Raquel; Pintado, Manuela; Oliveira, Ana LeiteIn situ cross-linked hydrogels have the advantage of effectively fulfilling the wound in its shape and depth. Amongst the new generation of natural-based biopolymers being proposed for wound care and skin regeneration, silk sericin is particularly interesting due to its exceptional properties such as biocompatibility, biodegradability, and antioxidant behavior, among others. In this study, a new enzyme-mediated cross-linked hydrogel composed of silk sericin is proposed for the first time. The developed hydrogel crosslinking strategy was performed via horseradish peroxidase, under physiological conditions, and presented gelling kinetics under 3 min, as demonstrated by its rheological behavior. The hydrogels presented a high degree of transparency, mainly due to their amorphous conformation. Degradation studies revealed that the hydrogels were stable in phosphate buffer solution (PBS) (pH 7.4) for 17 days, while in the presence of protease XIV (3.5 U/ mg) and under acute and chronic physiological pH values, the stability decreased to 7 and 4 days, respectively. During protease degradation, the present sericin hydrogels demonstrated antioxidant activity. In vitro studies using an L929 fibroblast cell line demonstrated that these hydrogels were noncytotoxic, promoting cell adhesion and massive cell colonization after 7 days of culture, demonstrating that cells maintained their viability and proliferation. In addition, the application of sericin-based hydrogel in an in vivo diabetic wound model validated the feasibility of the in situ methodology and demonstrated a local anti-inflammatory effect, promoting the healing process. This study presents a simple, fast, and practical in situ approach to produce a sericin-based hydrogel able to be applied in low exudative chronic wounds. Moreover, the study herein reported fosters the valorization of a textile industrial by-product by its integration in the biomedical field.
- Relationship between minerals and physicochemical parameters with fruit quality in ‘Rocha’ pear orchardsPublication . Dias, Cindy; Ribeiro, Tânia; Rodrigues, Ana Cristina; Vasconcelos, Marta W.; Ferrante, António; Pintado, ManuelaAt the same location, variability among orchards may be high, which is reflected in fruit quality, and it may be associated mainly with growers’ practices. This study aimed to identify physicochemical variability within pears (Pyrus communis L. cv 'Rocha') from three orchards from the same location and under the same climate conditions and correlate it with mineral composition.