Abstract
New phosphoryl oligosaccharides (POS) were prepared from potato starch hydrolysate. The inhibitory effect of POS on the formation of a calcium phosphate precipitate were investigated. POS were fractionated by ion-exchange chromatography into two fractions, PO-1 and PO-2. Both fractions, PO-1 and PO-2, had the ability to form a soluble complex with calcium, and fraction PO-2 had a stronger inhibitory effect on the formation of calcium phosphate precipitate, and made a more stable and soluble complex with the calcium ion. Fraction PO-1 was the main component of POs, and was composed of maltotriose, maltotetraose and maltopentaose to which one phosphate group was attached. Fraction PO-2 was predominantly composed of maltopentaose and maltohexaose to which at least two phosphate groups were attached. According to the reaction specificities of glucoamylase (GA) (EC3.2.1.3) and bacterial saccharifying a-amylase (BSA) (EC 3.2.1.1), and spectrometrical as well as chemical analyses, we determined the precise structure of the components fraction PO-1. In addition, it was found that fraction PO-1 was a suitable compound in producing the conjugate with ovalubmin (OVA) through the Maillard reaction and the conjugate could exhibit an inhibitory effect on the formation of a calcium phosphate precipitate.
