ผลของวิธีการแช่เยือกแข็ง การเติมไฮโดรคอลลอยด์ และวิธีละลายน้ำแข็งต่อคุณสมบัติทางกายภาพและเคมีของทาโกะยากิ

Abstract

This research aimed to study changes on qualities of frozen takoyaki. Study the freezing method, utilization of hydrocolloids to improve the quality of frozen takoyaki, and appropriate thawing methods using microwave oven and electric oven. Physicochemical properties (color, whiteness index, viscosity, chemical composition) of commercial takoyaki flour indicated that it was not single flour but presumably mixed cereal flour consisting of all-purpose flour, rice flour, and corn flour. Freezing methods affected physicochemical and sensory properties of takoyaki, especially after thawed. Although freezing by liquid nitrogen had the fastest freezing rate (83.2 ºC/min), it caused cracks on the surface of some takoyaki. These led to lower specific volume and higher drip loss (12.75+1.68%) of thawed takoyaki than those frozen by freezer (10.16+1.79%) and by air blast freezer (7.08+1.75%), respectively. All frozen takoyaki had lower sensory scores on crispness and shape after thawing than the unfrozen control. The inside-texture and overall acceptance scores of thawed takoyaki from air blast freezer were in the same range as those of the unfrozen control (p>0.05). Considering overall qualities, freezing by air blast freezer preserved quality of takoyaki better than freezing by freezer and by liquid nitrogen. Addition of hydrocolloids (Carboxymethyl cellulose (CMC), Xanthan gum, and Guar gum) at the concentration of 0-2.5% was studied to improve the quality of frozen takoyaki. Addition of CMC and Guar gum at all concentrations did not affect the lightness of the thawed takoyaki. While addition of Xanthan gum at 2 and 2.5% significantly reduced the lightness (p<0.05). Addition of CMC had the least effect on improving quality of frozen takoyaki. Adding Guar gum at 2.5% best improved the qualities (specific volume, texture, moisture content, and drip loss) of thawed takoyaki and was close to the unfrozen control. Three thawing methods consisting of microwave oven, electric oven, and a combination of microwave oven followed by electric oven, were studied. Thawed takoyaki by microwave oven had inferior qualities (specific volume, texture, moisture content, drip loss, and sensory quality) to those thawed by the other two methods. Thawed takoyaki by electric oven at 225 °C for 20 min and microwave at 800 W for 1 min followed by electric oven at 225 °C for 5 min had similar sensory quality to the unfrozen control (p>0.05).