Otimização da extração de compostos bioativos de plantas (melissa officinalis l., origanum vulgare l., e rosmarinus officinalis l.) Para utilização como conservantes naturais em “muffins de chocolate”

A muffin is a sweet snack which is baked and usually consumed throughout the day, highly appreciated for its spongy and soft texture, sweet flavour, as well as its chewiness, symmetrical shape and rounded brownish top. A recent trend from consumers is a pursuit for a more adequate diet, allied to a healthier way of life, translated in the seek for healthier foods with functional properties. These tendencies have led the food industry to develop healthier foods with natural ingredients that can confer beneficial properties for their consumers. One of the most important aspects in the development of food is its preservation, which relies, nowadays, on synthetic or artificial food additives. However, due to problems related to the consumption of food additives and consequent toxicity, natural alternatives are sought with less or no adverse effect, for example, the addition of natural preservatives derived from plants to extend the shelf-life and prevent deterioration. Among the natural matrices, rosemary, oregano and lemon balm are interesting candidates due to the high number of functional molecules which can be used to preserve food. The present work has two main objectives; on the one hand the optimization of the phenolic fraction of extracts from lemon balm, oregano and rosemary, and, on the other, using the best extracts as preservative ingredients in muffins, to produce these snacks without artificial preservative additives. The optimization was done with the aid of factorial fraction design and using ultrasound-assisted extraction. Furthermore, the antioxidant and antimicrobial activities were also performed on these extracts prior to their incorporation in chocolate muffins. Then, the nutritional profile of these muffins was analysed, as well as the organic and fatty acids, soluble sugars, texture and color parameters were performed. As expected, the extracts showed as similar effect on preserving the muffins as sodium sorbate while not changing any other parameters of the muffins. This work shows that plant extracts can be alternatives to synthetic molecules.