Effect of laccase from Trametes versicolor on the oxidative stability of edible vegetable oils

The increasing demand of natural food from consumers has limited the use of traditional methods to control the oxidation of lipids,such as synthetic antioxidants and hydrogenation.Besides,it has been reported that the use of enzymes is efficient to eliminate dissolved oxygen in foods such as vegetable oils.Laccase is a polyphenol oxidase and the reduction of oxygen to water is accompanied by the oxidation,typically,of a phenolic substrate.Laccase have become important,industrially relevant enzymes that can be used for a number of diverse applications such waste detoxification,textile dye transformation,food technologic uses,biosensor and analytical applications,bioethanol production,among others.The target of this study was to evaluate the effect of laccase enzyme from Trametes versicolor,on the oxidative stability of sesame,chia,peanut and sunflower oils,measured through the peroxide value(PV)and conjugated dienes(K232)and trienes(K270).The samples of oil with laccase showed higher PV,K232 and K270 than their corresponding controls,under the conditions evaluated(room temperature and 60◦C).The results suggest that fungal laccase has an unexpected pro-oxidant effect on vegetable oils,possibly promoted by products derived from the oxidation of phenols by enzymatic action.

New 5-Alkenyl Resorcinols from <i>Lithraea molleoides</i>(Vell). Eng.

Lithraea molleoides (Anacardiaceae) is a tree that grows in South America including Southern Brazil, Southern, and Eastern Bolivia, Southern Paraguay, Northern, and Central Argentina. Infusions, decoctions, or tinctures from its aerial parts (leaves, buds, and young stems) are employed in ethnomedicine mainly against respiratory, and digestive inflammations and illnesses. Antibacterial, antiviral, antioxidant, anti-inflammatory, and antinociceptive activities, among others, have been reported for L. molleoides. Many of its biological activities have been associated with the reported presence of 5-alkenyl resorcinols. Alkyl/alkenyl catechols and alkyl/alkenyl resorcinols are very common in members of the Anacardiaceae family and several activities have been attributed to them. This work describes the isolation and the structural elucidation of three new 5-alkenyl resorcinols isolated from Lithraea molleoides reported in nature for the first time.