| 摘要: | 本研究探討大豆蛋白之萃取條件與添加物比例(豆漿、甘油、大豆蛋白)對非傳統腐皮品質之影響。首先大豆豆粕藉改變萃取pH值(7-10)，利用鹼提酸沉法獲得大豆蛋白。先計算其固形物及蛋白質之回收率，以及進行氮溶指數、起泡性、乳化性等功能特性測定，最後再與市售大豆分離蛋白之功能特性結果比較其差異。
腐皮實驗先探討不同的甘油及豆漿比例(1:8；1:15；1:31)對於腐皮品質之影響，再比較不同市售大豆分離蛋白及其功能特性對於腐皮質地之各物理性能之相關性，以探討最適之腐皮製作條件。
結果顯示，在pH9、42℃的條件下以1:17之豆粕:鹼水，萃取一小時，在此條件下豆粕之回收率及蛋白質之萃取率為最高，而此大豆分離蛋白之起泡特性也較佳。
自製的大豆分離蛋白在氮溶指數、起泡性、乳化性、凝膠性等功能特性優於市售之大豆分離蛋白；而由使用市售大豆分離蛋白(SPI-A、SPI-B、SPI-C)所製成之腐皮其功能特性及外觀之結果推測，使用具有良好氮溶指數、起泡性、乳化性、凝膠性等功能性之大豆分離蛋白所製成的腐皮原料漿具有良好的分散性、黏稠性，腐皮成品也會呈現較好的外觀及功能特性。另外，試驗過程也觀察到，腐皮的質地特性受甘油含量多寡所影響。綜合各種腐皮測試 (顏色、厚度、抗拉強度)，以1：8之豆漿：甘油所製成之腐皮外觀較佳、厚度均勻分布，拉伸強度適中。
This study investigated the extract condition of soy protein from soy meal and the effect of soy milk, glycerin and soy protein ratio on the quality of non-traditional yuba. The soy meal was extracted by alkaline (pH7-10) and then precipitated by acid to obtain soy protein product. The recovery of solids and proteins of the soy meal were calculated, as well as the functional properties of nitrogen solubility index (NSI), foaming properties, emulsification properties of the protein was de-termined. For the experiment of non-traditional yuba, the impact of different glycerol and soymilk ratio of yuba was investigated first, then 5 different commercial soy protein isolate was used to produce the yuba and the physical properties of the yuba were compared.
The results showed that in the extraction condition of soybean meal: alkaline ratio of 1:17 and one hour extraction time, soy meal had the highest extraction rate and protein recovery, and the soy protein had best foaming properties in this extraction condition too. The functional properties (i.e., NSI, foaming properties, emulsification properties and gelation properties) of self-made soy protein isolate are better than the commercial soy protein isolates in this study. According to the func-tional properties and appearance of the yuba which made by different commercial soy protein isolate (SPI-A,SPI-B, and SPI-C), it can be speculated that better functional properties of soy protein isolate can produce better dispersion and viscosity of raw material slurry of yuba and better appearance and functional properties of yuba. In addition, the result also showed that the texture properties of yuba affected by the amount of glycerol content. In conclusion, according to the various tests (color, thickness, tensile Strength) result, the yuba made with soymilk: glycerol 1:8 had the better appearance, uniform thickness and moderate tensile strength. |
