Chemical and physical properties of reduced sugar carbohydrate food gels

Abstract

This study was designed to objectively and subjectively investigate the effect of high sugar (65% soluble solids) and low sugar (30% soluble solids) content on the chemical and physical properties of carbohydrate food gels. High sugar gels were prepared using sucrose. Low sugar gels were prepared using high fructose corn syrup of 90 dextrose equivalents (HFCS-90). Gelling agents used were high methoxyl (HM) pectin, low methoxyl (LM) pectin, carageenan, calcium alginate, a combination of carageenan with HM pectin and carageenan with LM pectin, and a combination of alginate with HM pectin and alginate with LM pectin. Quality attributes measured were pH, soluble solids, proximity equilibration cell a(,w), electronic hygrometer a(,w), bound water content, transition energy (H), water binding index (WBI), syneresis volume, spreadability, resistance to shear (surface strength) and sensory acceptance. Bound water, H, WBI were determined using differential scanning calorimetry Significant differences were found between the gels when a(,w), bound water, H, WBI, spreadability, surface strength, syneresis volume, and sensory panel results were analysed. Decreasing the solids content using HFCS-90 was found to decrease the bound water content, a(,w), spreadability, and surface strength; while the syneresis volume increased. Syneresis volume, spreadability, and surface strength can be predicted from the bound water content, a(,w), gel type and solids content. Gels in the alginate family exhibited characteristics similar to high sugar jams or spreads. Carageenan gels exhibited high syneresis volumes, low spreadability values, and high surface strength values. The incorporation of glycerol tended to increase the bound water content and a(,w), but the increases were not large. The increases would not affect spreadability, surface strength, or syneresis volume. The sensory panel could distinguish between gel types. The panelists preferred gels with firm texture, good spreadability, high sweetness, low acidity, and a good mouthfeel. Syneresis volume was not considered in the panelist's evaluation. The preferred high sugar gel was the LM pectin sugar gel, while the preferred low sugar gel was the alginate HFCS gel. It appeared from the subjective sensory panel evaluations that low sugar gels of the alginate HFCS type are approximately equivalent in acceptability when referred to the key parameters of high sugar HM pectin gels.