Chemical and instrumental characterization of pectin from dried pomace of eleven apple cultivars = Caracteriza o qu赤mica e instrumental de pectinas isoladas de baga o de 11 cultivares de ma

作者：Mariana de Fatima Sato; Dayana Carla Rigoni; Maria Helene Giovanetti Canteri; Carmen Lucia de Oliveira Petkowicz

来源：Acta Scientiarum - Agronomy, 2011.

• apple pomace
• dietary fibers
• pectin
• degree of esterification
• baga o de ma
• fibras dieteticas
• pectina
• grau de esterifica o

Pectic substances from eleven samples of dried apple pomace were extracted using an acid procedure (100 mM HNO3, 10 min., 80oC), dried, ground and stored in a P2O5 atmosphere. The degree of esterification was determined by the classical titrimetric method and confirmed by the instrumental FTIR method. The samples showed an average DE of 73% and the typical fingerprint in IR spectrogram. The steric exclusion chromatograms obtained with the multi-angle laser light scattering (MALLS) and refraction index (RI) detectors showed that all samples had a high molar fraction eluted at 36-38 min.,another large polysaccharide family had an elution time around 43 min, and some samples showed yet another low molecular oligosaccharide that appeared at 58-60 min. Gas chromatography of alditol acetate allowed estimates of the proportion of the neutral sugar in the samples. The ratio of galacturonic acid and rhamnose may give the average size of the galacturonan fraction. These results showed that yields of pectin extracted by the same acid procedure were slightly different. However, the degree of esterification of pectin was similar, with both factors pointing to the best sources in this group of varieties. Substancias p谷cticas de 11 amostras de baga o desidratado de ma foram extra赤das usando um procedimento 芍cido (HNO3 100 Mm, 10 min., 80oC), desidratadas, mo赤das e armazenadas em atmosfera de P2O5. O grau de esterifica o das amostras foi determinado pelo m谷todo titulom谷trico, confirmado pelo instrumental FTIR. As amostras mostraram DE m谷dio de 73% e o fingerprint caracter赤stico no espectrograma em infravermelho. Os cromatogramas de exclus o est谷rica, obtidos com o detector para espalhamento multiangular de luz a laser (MALLS) e com o 赤ndice de refra o (RI), indicaram que todas as amostras apresentam fra o de elevada massa molar, elu赤da a 36-38 min. e outra grande fam赤lia de polissacar赤deos com tempo de elui o de 43 min. Outros oligossacar赤deos de baixo peso molecular aparecem aos 58-6o min em algumas das amostras. A cromatografia gasosa dos aldit車is derivatizados permitiu estimar as propor es de a 迆cares neutros das amostras. A raz o entre os a 迆cares 芍cidos com a ramnose pode ser usada com parcim nia para a determina o do tamanho m谷dio das cadeias de 芍cido poligalactur nico.

• 出版日期2011