Avaliação da qualidade de óleos compostos obtidos de fontes alternativas

• Autor(a) principal: Veronezi, Carolina Médici [UNESP]
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/139406
• topic: Tecnologia de alimentos; Resíduos industriais; Frutas - Sementes; Óleos vegetais; Compostos bioativos; Antioxidantes; Food technology

The search for alternate sources for the extraction of vegetable oils grows every year, since the population seeks healthy oils with high oxidative stability. Thus, this study aimed at chemically characterizing the oils extracted from seeds of papaya (Carica papaya L.) and melon (Cucumis melo L.) cultivated in Brazil, evaluating their antioxidant activity, besides their contribution to soybean oil stability when subjected to thermoxidation (0, 5, 10, 15, 20 h) and storage at room temperature (0, 3, 6, 9, 12 months). Soybean (S), papaya (Pa), and melon (Me) oils were used in order to obtain the composed oils SPa (80:20 p/p), SMe (80:20 p/p), and SPaMe (60:20:20 p/p/p), the chemical composition of the seeds, and the physico-chemical properties and antioxidant activity of the oils being analysed. Papaya seeds presented significant quantities of lipids (25.4%), besides higher quantities of some macroelements, such as K, P, and Ca, when compared with melon seeds. In thermoxidation and storage at room temperature, the oils behaved very similarly. The compound oils presented good quality, due to low levels of free fatty acids, peroxide value, and conjugated dienoic acids at the end of thermoxidation and storage at room temperature. Palmitic and linoleic fatty acids stood out in all oils, except in papaya oil, which showed high level of oleic acid. The amount of total carotenoids decreased at the end of both processes. However, at the end of thermoxidation, differently from storage, only papaya oil presented significant quantity of carotenoids. In the oils studied, four different phytosterols were found, β-sitosterol being the most significant. Among tocopherol isomers found in the oils, γ-tocopherol stood out, except in papaya oil, which showed higher quantity of α-tocopherol. The methodologies of antioxidant activity showed several oscillations during the processes. However, the compound oils presented expressive antioxidant activity ...