Avaliação da atividade antimicrobiana do óleo essencial da casca da laranja pêra Citrus sinensis (L.) Osbeck

Abstract

Essential oils are aromatic compounds extracted from various parts of plants, including flowers, fruits, roots, bark, and others. These oils have been used for thousands of years throughout history and were mainly used in the medicinal field due to their phytotherapeutic properties. Today, they are mainly used in the development of cosmetics and medicines. One of the biggest challenges for the food industry is the production of products with a long shelf life, and to achieve this, they use synthetic additives. However, consumers' search for healthier alternatives has led the food industry to find solutions, and one of them is the use of essential oils as additives in food production, since the use of synthetic additives such as dyes, flavorings, and preservatives is linked to health problems such as allergies, food hypersensitivity, and cancer. Brazil stands out worldwide in the production and processing of oranges (Citrus sinensis (L.) Osbeck), generating a large amount of waste that is often discarded. Literature indicates that this waste can be used to extract essential oils. Therefore, this study was conducted to evaluate the antimicrobial activity of orange essential oil. For this purpose, the extraction was performed in triplicate using the hydrodistillation method at a constant temperature of 100 °C. After the oil was extracted, its physical properties (color, aroma and density) and chemical properties (acidity) were verified. In addition, the yield of the extracted oil was calculated. Finally, its antimicrobial activity was evaluated through the antimicrobial sensitivity test in which the fungi Penicillium sp and Aspergillus niger provided by the graduate students of the Chemical Engineering Teaching Laboratory (LEEQ) were used. In this technique, the discs used were made with filter paper with a diameter of 5 mm each. The discs were soaked in the oil and then placed on top of the medium inoculated with the microorganisms. The oil obtained had a homogeneous, colorless appearance and a characteristic odor of the fruit. While its acidity was 0.56%, its density was 0.81 g/mL and its yield was 1.77%. It was only effective against the microorganism Penicillium sp, forming an inhibition zone of 11 mm. This activity is explained by the presence of its major component, limonene.