Effects of Various Starches on Properties of Rakkasei-tofu (Peanut Tofu)

Abstract

Rakkasei-tofu (peanut-tofu) is a kind of a processed food which is made from peanut milk squeezed from ground peanut flour with water, starch and water. It is usually prepared using sweet potato starch in the Okinawa region. We made the Rakkasei-tofu from seven kinds of starches: kuzu starch, sweet potato starch, a low temperature gelatinization sweet potato starch called "minazuki", corn starch, tapioca starch and modified tapioca starches called "PB 108" and "PB 2000". The texture (hardness, cohesiveness and adhesiveness), degree of gelatinization and sensory evaluation were measured for each of these preparations. The physicochemical properties (particle size distribution, swelling power, solubility, X-ray diffraction, thermal properties using a differential scanning calorimetry; DSC and pasting properties using a Rapid Visco Analyzer; RVA) of the starches were also examined. It was demonstrated that Minazuki gelatinized at a low temperature similar to PB 108 and PB 2000. As the storage period increased, the cohesiveness and the gelatinization degree of the Rakkasei-tofu made from kuzu and sweet potato decreased, but those made from minazuki and PB 2000 retained higher cohesiveness and a greater degree of gelatinization. These results suggest that the Rakkasei-tofu made from starches showing low temperature gelatinization had good keeping qualities.