Commercial cell wall hydrolytic enzymes for producing pectin enriched products from butternut (Cucurbita moschata, Duchesne ex Poiret)

FISSORE ELIANA N; PONCE NORA M; WIDER EVA A; STORTZ CARLOS A; GERSCHENSON LÍA N; ROJAS ANA M

JOURNAL OF FOOD ENGINEERING

ELSEVIER SCI LTD

Año: 2009 vol. 93 p. 293 - 301

0260-8774

A cell wall-enriched butternut (Cucurbita moschata Duch ex Poiret) powder was obtained by drying pumpkin mesocarp wastes; this powder was used as the substrate for industrial cellulase (A-product) or hemicellulase (B-product) action. Yields obtained were 4.70 g of A-fraction or 6.12 g of B-fraction per 100 g of pumpkin powder. Both pectin enriched products were water soluble fibres and only the latter showed important thickening effect at 20 g dm-3-concentration in water. This product was a highly methylated (Methylation degree, DM, 72.6) pectin with 45.2 g/100 g of galacturonic acid and 11 g/100 g of neutral sugars. Cellulase produced intense hydrolysis leading to a lower methylated (DM: 54.2) A-fraction. It was observed that, not only average molecular weight but also the molecular structure derived from chemical composition affected flow behaviour and viscosity enhancing capacity. As A-fraction was enriched in RG-I, probably, rhamnose kinks were responsible for the poor thickening effect at 20 g dm-3-concentration in water, in spite of its homogeneous molecular weight profile, which showed only one peak at 793000. This fraction presented the lowest density of macromolecular interactions in water, behaving as a diluted hydrocolloid solution as confirmed by its fitting to the Cox-Merz rule. Both isolated soluble fractions produced a delay in the glucose dialysis assay. This is an interesting effect for nutrient absorption control in the case of alterations in glucose metabolism.