Kinetics of Starch Gelatinisation and Mass Transfer During Cooking of Taro (Colocasia esculenta L. Schott) Slices
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| Format: | Article |
| Language: | English Slovak |
| ISSN: | ISSN 0038-9056 |
| Online Access: | http://www.viks.sk/chk/star_3_4_03_170_176.doc |
| Abstract: | Summaries. Taro slices of different thickness (5,10 and 15 mm) were cooked for varying periods of time (5, 10, 20 and 40 min) and dried at different temperatures (70, 80 and 90 °C). Flours obtained from the slices were evaluated for their degree of gelatinisation, their content of sugars and phenolic compounds. The results showed that starch gelatinisation as well as the diffusion of sugars and phenolic compounds during cooking each followed a first-order reaction of the general form ln(1 -) = -kt. The gelatinisation rate constant, kG, and the rate constants for the diffusion of sugars and phenolic compounds, kL, increased with temperature and decreased with slice thickness. Conclusion. The gelatinisation of taro starch follows an exponential model. The reaction rates are temperature-dependent. Arrhenius-type equations were found to relate the rate constant of gelatinisation, kG, to the inverse of absolute temperature. Apparent activation energy values show that, within the temperature range studied (70-90 °C), the rate of gelatinisation reaction is significantly dependent on the thickness of slices. In addition to gelatinisation that occurs during cooking, the leaching of sugars and phenolic compounds also takes place. This leaching process is influenced by cooking temperature and the size of taro slices. In the background of the knowledge of these factors influencing the leaching of sugars and phenolic from taro during cooking, further studies have to be carried out in order to optimise the conditions of gelatinisation of taro so as to guarantee the quality of the instant flour and, eventually, the food products obtained from it. |
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| ISSN: | ISSN 0038-9056 |
