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Toxicity of cadmium and zinc on two microalgae, Scenedesmus obliquus and Desmod...

Aquatic environments often contain toxic heavy metals that may enter the food web via uptake by microalgae and eventually cause severe poisoning problems at higher trophic levels. The effects of Cd and Zn cations upon growth of two native green microalgal species, Scenedesmus obliquus and Desmodesmus pleiomorphus (previously isolated from a polluted site in Northern Portugal), were accordingly evaluated. Growth...

Impact of thermal blanching and thermosonication treatments on watercress (Nast...

The objectives of the present work were to optimise watercress heat and thermosonication blanching conditions, in order to obtain a product with better quality for further freezing, and to evaluate the effects of thermosonication on the microstructure of watercress leaves. In a chart of optimal time–temperature conditions for a 90% peroxidase inactivation (imposed constraint), vitamin C (objective function) and...

Effect of particle size upon the extent of extraction of antioxidant power from...

The dependence of the extent of aqueous extraction of antioxidant compounds on particle size and contact time was studied for three important medicinal plants, that are commonly used in infusions: agrimony, sage and savoury. The effect of extraction time was dependent on the plant considered; however, ca. 5 min can be taken as the minimum period required to assure an acceptable degree of extraction of those com...

Effect of different levels of CO2 on the antioxidant content and the polyphenol...

Abstract: Pears (Pyrus communis L. cv. ‘Rocha’) were exposed to air or controlled atmosphere (CA) containing various concentrations of CO2: 0, 0.5 and 5 kPa, all with 2 kPa O2. After 4months of storage at 2 ◦C, the fruits were transferred to air at room temperature, and assessed in terms of soluble solids, titratable acidity, pH, incidence of brown heart and flesh browning, phenolic content, vitamin C content a...

Microstructural analysis of fresh-cut red bell pepper (Capsicum annuumL.) aimin...

Microstructural analysis of fresh-cut red bell pepper (Capsicum annuum L.) for ...

The main objective of this work was to evaluate the microstructure of fresh-cut red bell pepper (Capsicum annuum L.) after cutting, when maintained (for 0,4 and 7 d) under refrigerated storage (2°C). In order to assess the microstructure of the product, scanning electron microscopy (SEM) was applied; however, to improve this technique, preparation procedures and quantitative image analysis were specifically dev...

Influence of low oxygen and high carbon dioxide on shredded Galega kale quality...

Respiration rate, sensory attributes, colour alterations, and water, chlorophyll and ascorbic acid contents were monitored during storage of shredded Galega kale (Brassica oleracea var. acephala DC.) at 20 ◦C to define an adequate range of O2 and CO2 partial pressures for product preservation. Different low O2 and high CO2 atmospheres were tested. First, tolerance to low O2 partial pressures (1, 2, 3 or 21 kPa ...

Effects of preharvest, harvest and postharvest factors on the quality of pear (...

Pears (cv. Rocha’) grown at two locations and picked up at various times during the harvest season were assessed for firmness and colour, following 9 mo of storage under air or under controlled atmosphere conditions. A second-order polynomial was able to accurately fit the effect of time of harvest on pear’s quality, in an essentially empirical modelling effort; the best estimates of the parameters therein dep...

Sensorial and physicochemical quality responses of pears (cv Rocha) to long-ter...

Pears (cv Rocha) kept under controlled atmospheres (CA) and air were evaluated after longterm storage in terms of sensory attributes and physicochemical parameters, namely colour, firmness, polyphenoloxidase (PPO) activity and concentration of hydroxycinnamic compounds. The CA conditions were all combinations of 2 and 4% (v/v) O2 with 0.5 and 1.5% (v/v) CO2. Storage under CA conditions produced a beneficial eff...

Relationship between instrumental and sensory quality parameters of various pea...