- 期刊
射頻乾燥黃豆渣之研究
Study of Radio Frequency Drying on Soybean Residue
摘要
製備豆漿所產生的黃豆渣因水分含量太高會快速敗壞，而不利於後續的食品加工應用。射頻是一種能藉由電場的快速轉換使食品中極性水分子或離子轉動摩擦快速升溫的技術，將射頻配合送風可克服熱傳和質傳障礙而快速乾燥。故本研究之目的是建立黃豆渣之射頻-45℃冷風乾燥條件，並與45℃冷風乾燥的黃豆渣比較乾燥速率，能量消耗和產品的顏色，抗氧化活性。結果顯示，射頻-45℃冷風乾燥1、1.5和2kg的黃豆渣牙別只需要14-22和30 min即可將水分含量由80％降低至15％，且乾燥過程只有恆率期，水分含量呈線性下降。射頻-45℃冷風乾燥速率是45℃冷風乾燥速率的25倍且總能量消耗只需1/9，射頻45℃冷風乾燥黃豆渣的總多酚含量和清除DPPH自由基能力皆顯著高於冷風乾燥黃豆渣，在顏色部分，二者則無顯著差異。
並列摘要
Soybean residue is high moisture content after soybean milk extrusion; therefore it is rapidly decaying and hard to be applied in food industry. Radio frequency (RF) can rapidly heat up water molecules or ions in food by rapid conversion of electric field; therefore, RF drying can overcome the heat and mass transfer resistances to accelerate drying processing. The objectives of this study were to dry the soybean residue by RF-45℃cold air. Then dried soybean residues by RF-45℃cold air and cold air drying were analyzed their drying rate, energy consumption, color and antioxidant activities. The results showed that they required 14, 22 and 30 min for reducing moisture content from 80% to 15% to dry 1, 1.5 and 2 kg of soybean residue by RF- 45℃cold air, respectively. RF-45℃cold air drying rate was 25 times of 45℃cold air drying, and the total energy consumption was reduced to 1/9. The total polyphenols content and DPPH free radical scavenging ability in RF-45oC cold air soybeans residues were higher than cold air dried soybean residues, but there was no significant difference in color between two different drying methods of soybean residue.