| Summary: | 碩士 === 靜宜大學 === 食品營養學系 === 90 === Three varieties of taro, including Betelnut and Mein taro of Colocasia esculenta and KCX01 taro of Xanthosoma sagitifolium, were used to investigate the effect of deep fat fried treatment at 175℃ with different time on the texture profile, microstructure and quality of taro chips. Moreover, the correlation coefficient among compositions texture and sensory profile of fried taro chips were analyzed in this study. The results showed that water content of fried taro chips were decreased with the extent of fried time. The oil content of fried taro chip was increased in the initial stage, then decreased eventually comparing with water content of fried taro chip. Dehydration rate of Betelnut chip was the fastest in three experimental samples. As 60 sec fried treatment, water content and water activity of fried taro chips were sharply decreased to 5% and 0.452, respectively, comparing with Betelnut taro chips, it took 90 sec for KCX01 taro chips and 120 sec for Mein taro chips to reach 5% water content and 0.5 water activity. According to the results of scanning electronic microscopy, the central location of fried taro chip exhibited wider hollow than fresh taros. Starch complex was filled in the taro cellular. The surface of taro cell of fried taro chips was shrunken and wrinkled with the extent of fried time(30~150sec). The lightness (L-value) was decreased with the increase of fried time but increased in breaking force. Water content of different section of fresh taro was significant difference (p<0.05). Moreover, after deep fat fried treatment, water content of fried taro chips from head and central section were higher than from tail section of taro but no difference in oil absorption of fried taro chips (p<0.05). As fried time increased, the crispness of sensory profile increased. However, the crispiness of taro chips did not significantly change when fried time was over 120sec oppositely, the acridity of fried time was extended. According to the analysis of fried taro chips, water content negatively correlated with oil absorption and breaking force (r=-0.84~-0.85 & r=-0.89~-0.95). Water content of fried taro chip positively correlated with greasiness of sensory profile (r=-0.72~0.99). However, a negative correlation was found between water content and crispiness of fried taro chips (r=-0.84~-0.99). Highly correlation was found between content of calcium oxalate and acridity of fried taro chip(r=0.87~0.97). Of course, the breaking force of texture profile correlated well with crispness of fried taro chip. Comparison of water content and water activity of three varieties of taro, it took 60 sec at 175℃ to dehydrate to 5% of water content and 0.5 of water activity for fried Betelnut taro chips. In this situation, the total plate count of Betelnut taro chips was less than 2 log CFU/g. However, it took more than 120 sec to reach the same goal for fried KCX01 and Mein taro chip. These evidences would concluded that different deep fat fried treatments were necessary for different varieties of taro because of the difference in composition and cell structure of taro.
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