Pectinas de casca de manga (Mangífera índica L.) cv. Ubá: Otimização da extração, caracterização físico-química e avaliação das propriedades espessantes e gelificantes

• Ano de defesa: 2013
• Autor(a) principal: Oliveira, Anderson do Nascimento
• Orientador(a): Ramos, Afonso Mota
• Banca de defesa: Romero, Javier Telis , Sousa, Rita de Cássia Superbi de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Ciência e Tecnologia de Alimentos
• Departamento: Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos
• País: BR
• Palavras-chave em Português: Ácido citrico; Oxalato de amônio; Grau de esterificação; TPA; Massa molar; Reologia
• Palavras-chave em Inglês: Citric acid; Ammonium oxalate; Degree of esterification; TPA; Molar mass; Rheology
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/487

This work aimed to study the extraction of pectin from Ubá mango peelsby applying different extraction methods, and using differentextractors agents, as well as to characterize the obtained pectins regarding their physical, chemical and structural properties. To study the extraction, three extractors were evaluated (hydrochloric acid, citric acid and oxalic acid-ammonium oxalate, OAAO). A Central Composite Design (CCD) with three independent variables (temperature, time and pH or concentration) was used for the experiments design. Response variables were extraction yield, degree of esterification (DE), viscosity and browning index (BI). The data were subjected to regression analysis to obtain the adjusted models. The pectins extracted under the conditions chosen for each extracting agent were characterized and evaluated for their gelling and thickening properties. The commercial citrus pectin of high methoxyl was also evaluated for comparison. It was found that the extraction method strongly influenced the variables extraction yield, degree of methoxylation and thickening capacity of pectins. According to the extracting agent used and the conditions employed, there was obtained extraction yields ranging from 7.79 to 20.61% of peel flour (dry basis) and DE ranging 32.3 to 94.8%. However, when adopting the conditions leading to of highest extraction yields, pectins were more degraded (hydrolysis of the polymer chain) and showed less thickening capacity, due to the more harschconditions of extraction. This indicates that extraction yield must not be assessed alone. From the adjusted models,suitable conditions for extractionwere determined taking into account the extraction yield, degree of esterification and thickening capacity of pectins: hydrochloric acid (85 ° pH 2.5, 45 min), citric acid (80 °C, C, 0.6%, 60 min) and OAAO (0.25% ammonium oxalate, 80 °C, pH 4.6, 60 min). Under these conditions, the mango pectins showed galacturonic acid content ranging from 63.5 to 70.9% (w/w), degree of methoxylation between 64.2 to 69.8% and low degree of acetylation, which ranged from 0.9 to 1.1%. The monosacaccharides arabinose (6,8 to 12,6%, w/w), galactose (9.9 to 13.5% w/w) and glucose (3.7 to 10.5%, w/w) were the most abundant ones. Intrinsic viscosity values solutionsof mango pectins ranged from 4.1 dL g-1 (HCl) to 4.6 dL g-1 (OAAO), whereas for commercial pectin it was about 3 dL g-1. This indicated that mango pectinsobtained in this work, especially those extracted with ammonium oxalate, showed more pronounced thickening capacitycompared to the commercial sample.It was also found that mango pectins had lower gelling capacity, compared to the commercial sample. The whole results pointed out that the studied mango peel pectins has good technological applicability in food industry, especially asthickener agents, contributing to valorize this material, which is often discarded as a waste during mango processing.