The pro-antioxidant activity of carrot, cauliflower, celery, eggplant, garlic, mushroom, onion, white cabbage, white potato, tomato, yellow bell pepper, and zucchini was investigated. Juices obtained by centrifugation of vegetables were treated at different temperatures (2, 25, 102 °C) and assessed for antioxidant activity (AA) using a model system β-carotene−linoleic acid. Antioxidant activity of all vegetable juices showed a linear correlation with time. The equations of all straight lines obtained showed positive slope values indicating either an increase in antioxidant activity or a decrease in prooxidant activity during the reaction. Negative intercept values were found when the juices showed prooxidant activity at least during the first phase of the reaction. Mushroom and white cabbage always showed more than 80% AA, while cauliflower, celery, and eggplant showed such high AA only after boiling. Tomato and yellow bell pepper were always prooxidant. Cluster analysis allowed the vegetables to be divided into five groups according to their anti- and prooxidant behavior as a function of thermal treatment and reaction time. Vegetable juice components were separated on a Bakerbond C18 solid-phase extraction cartridge according to their polarity, and the AA of the bound and unbound fractions of each vegetable was also tested. Keywords: Vegetables; lipid peroxidation; antioxidants; prooxidant

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The ability to rapidly and efficiently digest and identify an unknown protein is of great utility for proteome studies. Identification of proteins via peptide mapping is generally accomplished through proteolytic digestion with enzymes such as trypsin. Limitations of this approach consist in manual sample manipulation steps and extended reaction times for proteolytic digestion. The use of immobilized trypsin for cleavage of proteins is advantageous in comparison with application of its soluble form. Enzymes can be immobilized on different supports and used in flow systems such as immobilized enzyme reactors (IMERs). This review reports applications of immobilized trypsin reactors in which the IMER has been integrated into separation systems such as reversed-phase liquid chromatography or capillary electrophoresis, prior to MS analysis. Immobilization procedures including supports, mode of integration into separation systems, and methods are described.

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