Pimentas do gênero Capsicum: constituintes químicos e potencial antioxidante

• Autor(a) principal: Silva, Vânia Maria Barboza da
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/12737
• topic: Pimentas Capsicum; Perfil de ácidos graxos; Composição nutricional; Capsaicinoides; Atividade antioxidante; Estabilidade oxidativa; Capsicum peppers; Fatty acid profile; Nutritional composition; Capsaicinoids; Antioxidant activity; Oxidative stability; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS

Peppers of the genus Capsicum present as a sensorial characteristic the pungency, due to the presence of capsaicinoids, mainly of capsaicin. These substances have biological activities, among them protection against oxidative processes. Although these peppers are consumed worldwide, few studies have reported a complete study of nutritional composition, bioactive compounds and the effect of pepper extracts on edible oils. In this context, this research presents the nutritional composition of the three Capsicum peppers most consumed in Brazil: malagueta (C. frutescens), cheiro (C. chinense) and dedo de moça (C. baccatum); the composition of fatty acids determined by Gas Chromatography (GC) using indirect transesterification; the use of green chemistry to obtain extracts with solvents of low toxicity, evaluation of the antioxidant potential through the determination of the total phenolic content by the Folin-Ciocalteau method; evaluation of antioxidant efficiency using the ABTS, FRAP and DPPH methods; investigation of the content of capsaicinoids by spectroscopic techniques Infrared (IV) and Nuclear Magnetic Resonance of Hydrogen (1H NMR); determination of the effect of the addition of the hydroalcoholic extracts of the peppers on the oxidative stability of the soybean oil using the Rancimat method and study of the thermal behavior of the extracts by Thermogravimetry (TG) in non-isothermal mode. Results showed that the protein content in the peppers varied from (0.11 ± 0.03 to 1.73 ± 0.06%), the lipid content of (0.39 ± 0.05 to 0.83 ± 0.04%) and carbohydrate (4.56 ± 0.05 to 9.96 ± 0.05%) g / 100 g sample. O perfil de ácidos graxos mostrou uma composição semelhante das três pimentas no teor do ácido palmítico (C16:0): 20% em C. frutescens e 23% em C. baccatum e em C. chinense. Linoleic fatty acids (C18: 2) were the majority in the three peppers and only C. chinense exhibited considerable omega-3 -linolenic content (14%). The quantification of the total phenolic content ranged from 19.95 ± 0.25 to 38.98 ± 0.46 mg EAG.g-1 extract, with the most significant value for the ethanol / water extract (8: 2) of the pepper C. frutescens. The evaluation of the antioxidant capacity by the DPPH and ABTS methods showed that water was the most effective solvent in the extraction of antioxidants, and the EC50 value in the aqueous extracts of the three peppers ranged from 57.49 ± 0.51 to 110.66 ± 0.58 and 34.28 ± 0.51 to 138.63 ± 0.33 μg / mL extract respectively. The best result in these analyzes was obtained for C. frutescens pepper. From the FRAP method, the extracts with the highest antioxidant capacity were obtained with the ethanol / water mixture (80:20) for the three peppers, with C. frutescens and C. baccatum not differing statistically and showing the best results 175.48 ± 0 , 77 and 175, 70 ± 0.38 μM extract Trolox.g-1, respectively. Techniques IV and 1H NMR showed results that corroborated each other regarding the higher expression of capsaicin in the ethanol / water (80:20) extract of C. frutescens pepper. The values of the oxidative induction periods obtained in the Rancimat method showed that the ethanol / water extracts (80:20) of the three peppers increased the stability of the 200 mg.kg-1 soybean oil and the pepper extract C. frutescens was the most efficient. The extracts composition with the synthetic antioxidant tert-Butylhydroquinone (TBHQ) showed synergism and the composition (100 mg.kg-1 TBHQ + 100 mg.kg-1 C. baccatum) showed to be more effective than the TBHQ in the concentration of 200 mg.kg-1, the maximum allowed in edible oils in Brazil. The thermogravimetric analysis showed that the ethanol / water extracts (80:20) presented the first step of mass loss at temperatures close to 200 ºC, showed that there was no volatilization of the substances present in the extracts at the temperature of the Rancimat test.