Physical Properties of Mixed Gel of Fucoidan and Agar and Their Applications in Functional Foods

Abstract

In order to apply the fucoidan which is functional characteristic biopolymer, we prepared the novel gel models based on agar. And, we measured the physical property of agar/fucoidan mixed gel by dynamic oscillatory rheometer, thermo-optical analyzer (TOA) and texture profile analyzer (TPA). For experimental, one percent agar, fucoidan and mixtures of 1wt%, 80/20, 60/40, 40/60 and 20/80 agar and fucoidan were prepared under constant stiring at 90°C. As the results of performing frequency and temperature sweep, one percent of Agar/water mixture and agar/fucoidan solutions in the ratios of 80/20 and 60/40 have similar gel point temperatures. Agar/fucoidan mixed gels are lower in elasticities than agar gels. Sol-gel transition temperature of agar solution has broad range of 25 to 38°C. However, above 0.5wt% agar, the sol-gel transition temperature remained steady. In comparison with the agar gels and agar/fucoidan mixed gels, results show a similar properties in rheological behaviors. To observe their hysteresis, we measured changes and differences in transmitted light. As a result of hysteresis, the fucoidan does not affect the melting point of agar/fucoidan mixed gel. Both agar and agar/fucoidan mixed gels showed no difference in fracturability, adhesiveness, springiness and even hardness. Accordingly, agar gels and agar/fucoidan mixed gels have similar physical properties and can be applied gel-type food as a functional ingredient.