Coberturas para conservação de morangos: desenvolvimento, aplicação e caracterização de coberturas bioativas de alginato de sódio e de ágar-ágar adicionadas de óleos essenciais de tomilho (Thymus vulgaris L.) e de laranja doce (Citrus aurantium var. Dulcis) com propriedades antimicrobianas.

Abstract

The change in eating habits has been taking place all over the world, and the search for a healthier life is one of the factors that encourage the sale of minimally processed foods, such as strawberries, however, it is a fruit that has a Shelf life after harvest is very short. Among the factors responsible for the loss of its quality are the high metabolic activity and the high susceptibility to microbial attack. Thus, it is important to identify qualitative aspects, especially those focused on the care of conservation and prevention of contamination by microorganisms. An alternative technology increasingly used and evaluated as a viable procedure to increase the shelf life of fruits is the use of edible coatings, together with the addition of essential oils in order to preserve the shelf life of these fruits. The work aimed to develop, apply and characterize the effect of using bioactive edible coatings, based on agar-agar or sodium alginate, added with essential oils of thyme and/or sweet orange, with antimicrobial properties, especially anti-Listeria monocytogenes on The strawberry. The effect of the coatings on the physicochemical, microbiological and sensory characteristics that determine the shelf life of strawberries was verified in the times of 1, 8 and 15 days after the product was elaborated. The effect against Listeria monocytogenes bacteria in strawberries artificially contaminated with this microorganism was also evaluated. It was possible to determine that the alginate coating, added with sweet orange and thyme essential oil, presented the best results, both from a physicochemical and antimicrobial point of view in the analyzed samples. As for Listeria Monocytogenes, the coating applied after the contamination of the fruit showed an antimicrobial effect. Sensory analysis using the Implicit Association Test method had an association of “yes” or “no” responses with time in seconds, related to each coverage presented.