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CONSTENLA Diana Teresita
congresos y reuniones científicas
Título:
Intrinsic viscosity of pectin from sunflowerhead residues
Autor/es:
CONSTENLA, D.; LOZANO, J.E.
Lugar:
Sevilla
Reunión:
Congreso; III iberoamerican Congress of Food Engineering; 2001
Resumen:
Abstract Sunflower heads are a promising source of pectin, which is naturally low in methoxy content. However, the sunflower heads are currently discarded during seed harvest. Since the heads are rich in pectin, containing 18 to 24% after seed removal, they have been suggested as a commercial source of pectin industry. Pectin was isolated from sunflower head residues with a solution of sodium hexa-metaphosphate. The yield of pectin was 7.9% of the head weight. Galacturonic acid was 91.6%, determined by colorimetric procedure. The pectin has a degree of methylation of approximately 14.4%, determined by gas chromatography and 1.97 % acetyl ester content determined by enzymatic method. Sunflower pectin molecular weight was estimated by applying the Mark Howink? Sakurada equation, as a function of intrinsic viscosity. Determination was made in the range of pectin concentration 0.1%-0.4% in NaCl 0.1M. Viscosity measurements were performed at 25ºC with a Bohlin RVO stress controlled rheometer using concentric cylinders geometry (C25). Intrinsic viscosity of sunflower pectin and commercial pectin unstandardized (Genu pectin types LM-101 AS and LM 104-AS) were compared. Intrinsic viscosity of sunflower pectin was much higher than citric commercial pectins. Average molecular weight of the sunflower pectin was estimated in 190,000 ds.