Chemical and functional properties of cell wall polymers from two cherry varieties at two developmental stages.

BASANTA M. F.; DE ESCALADA PLA M. F.; STORTZ C. A.; ROJAS A. M.

CARBOHYDRATE POLYMERS

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2013 vol. 92 p. 830 - 841

0144-8617

Aceptado 26 de julio de 2012: The cell wall polysaccharides from the Regina and Sunburst varieties of cherry at two developmental stages were extracted sequentially, and their changes in monosaccharide composition and functional properties were studied. Cell wall extraction with water at room-temperature released loosely-attached pectins. They presented a lower proportion of D-galacturonic acid (GalA) with respect to rhamnose than ionically-bound pectins (extracted with CDTA), as well as lower thickening effects of their respective 2 % aqueous solution: the lowest Newtonian viscosity and shear rate dependence during the pseudoplastic phase. On the other hand, Na2CO3 solution extracted RG I-enriched pectins with long arabinan side chains, which produced true gels in water at 2 % concentration. Both the chemical composition and the molecular weight distribution of pectins contributed to the rheological behavior. The insoluble residue remaining after CDTA extraction of cell wall polysaccharides showed the best hydration properties due to the presence of ferulate cross-linked pectins. Pectin loss after the subsequent extractions with Na2CO3 and KOH solutions led to the lowest hydration ability of the insoluble residues, whereas the swelling capacity was related to the specific volume and, hence, to sample porosity. Apparently, the alkaline exhaustive extraction left a residue of amorphous cellulose, which explained the highest swelling capacity. Chemical composition and functional properties of cell wall polymers were dependent on cherry variety and ripening stage, and helped explain the contrasting firmness of Regina and Sunburst varieties.