Liquefaction conditions of Okara by Microwave Heating
Hiroshi SHIMOFURUYA, Kyosuke UCHIDA, Yoshihiko KUNIEDA, Yasuyuki TAKAGI, Ikuo HAYASHI and Ikukatsu SUZUKI
Department of Materials Science and Engineering, Suzuka National College of Technology,
Shiroko-cho, Suzuka-shi, Mie 5100294, Japan
Department of Clinical Nutrition, Faculty of Health Science, Suzuka University of Medical Science,
Kishioka-cho, Suzuka-shi, Mie 5100293, Japan
(Received December 2, 2010; Accepted January 14, 2011)
Abstract
Recently, microwave heating has become an increasingly popular method of heating. It is replacing the classical method because it is clean, cheap, and convenient. In this study, the liquefaction of Okara under microwave irradiation is investigated under varying parameters: reaction time, concentration of sulfuric acid, and the ratio of Okara and polyethylene glycol 400 (PEG400). Results showed the optimum liquefaction condition is obtained at 60min of reaction time, a 5% concentration of sulfuric acid, and ratio of Okara to PEG400 of 1:5. Under optimum conditions, microwave heating had a conversion ratio of 96%, and the liquefied Okara was dark-brown. On the other hand, when Okara was liquefied under conditions identical to those used in conventional heating, the conversion ratio was about 67%. Consequently, microwave heating is more effective than conventional heating.
Keywords:
Microwave heating, Liquefaction, Okara