In this study the differences in texture profile analysis (TPA), oil-uptake, and microstructure of donuts during atmospheric frying and vacuum frying (20 torr) were compared. Two types of donuts (cake donut and yeast-raised donut) with two temperature levels (140oC and 160oC) and three frying times (3, 4, and 5 minutes) were used for frying. Vacuum frying had a lower a-value on the surface of the cake donuts and formed larger pores and a rougher microstructures than the atmospheric deep-fried donuts. The L-value of the donut decreased with vacuum frying, and the hardness of the cake donut increased with both frying temperature and time. Scanning electron microscopy (SEM) of donuts under atmospheric frying showed various sizes of starch granules attached to the internal structure of the gas holes. There appeared to be a lesser amount of starch in the cake donuts that were vacuum fried and their surface was smoother than that of donuts that were fried under atmospheric condition. The oil content of cake donuts was lower with vacuum frying than with atmospheric frying. However, the oil content of yeast-raised donuts was lower with atmospheric frying than with vacuum frying. In both types of donuts, the donuts deep-fried under atmospheric conditions at 140oC for 5 minutes had higher sensory scores than any of the other processing conditions. 本實驗以常壓及真空油炸方式進行蛋糕及酵母甜甜圈製作，以140℃及160℃分別於常壓及真空油炸 (20 torr) 3、4、5分鐘，探討對甜甜圈質地剖面分析 (TPA)、吸油量及內部組織微細構造之影響。實驗結果顯示，以真空油炸所製得之酵母甜甜圈，外表色澤紅色度值 (a) 低於常壓油炸者。真空油炸製得之蛋糕甜甜圈，形成的內部組織孔洞較大，結構較粗糙，成品內部亮度值 (L) 低於常壓油炸者。蛋糕甜甜圈隨著油炸溫度與時間之增加，硬度值 (Hardness) 也隨之增加。以掃描式電子顯微鏡 (Scanning electron microscopy) 觀察甜甜圈微細構造，發現以常壓油炸之蛋糕甜甜圈內部組織氣孔壁膜佈滿大小不一澱粉顆粒，而真空油炸蛋糕甜甜圈澱粉顆粒明顯變少，表面較為平整。蛋糕甜甜圈的含油量在真空油炸條件下低於常壓油炸者，但酵母甜甜圈則在常壓油炸條件下有較低之含油量。經品評試驗後，不論是蛋糕甜甜圈或是酵母甜甜圈皆以140℃、5分鐘常壓油炸者整體接受性最佳
關聯:
Taiwanese Journal of Agricultural Chemistry and Food Science 47(5)：p.238-249
