真空油炸竹筍製程之研究

Abstract

本研究選用麻竹筍及桂竹筍為材料，進行以下實驗：（1）以真空油炸方式製造類似休閒點心的竹筍脆片，並探討真空油炸竹筍的最適製程；（2）將真空油炸竹筍進行貯藏試驗，探討產品在貯藏期間的品質變化及安定性；（3）比較真空與常壓下加熱的大豆油，在不同加熱時間，是否對Salmonella typhimurium TA100具有致突變性。 真空油炸竹筍的最適製程結果顯示，兩種筍在沸水烹煮下，殺菁時間20分鐘即可達到最低的含水量與最佳之質地，且足以去除過氧化酵素活性。切片試驗中，桂竹筍以圓形橫切片，麻竹筍以縱切片可分別達到較佳脫水率及較高品評分數。浸漬液則都以30 oBrix麥芽糖浸漬2小時的脫水效果最理想。以二因子五層階之反應曲面法，經感官品評之嗜好性試驗所得之最適真空油炸條件為，真空度80 Torr，桂竹筍油炸溫度94至98 ℃，油炸時間25至28 min；麻竹筍為油炸溫度101至103 ℃，油炸時間23至25 min。 在貯藏試驗結果顯示，最適產製條件之真空油炸竹筍在透明包裝袋包裝下，可於室溫下貯藏時間達三個月，仍保有良好品質。而安氏試驗法（Ames test）致突變性試驗中則發現，大豆油不論在真空或常壓下，經96小時長時間加熱後對Salmonella typhimurium TA100均不會產生致突變性，但真空加熱的大豆油保有較好的色澤。

Both Ma and Makino’s bamboo shoots were chosen as the materials in this project. The main purposes were (1) To develop a crunchy snack using bamboo shoots as the raw material and vacuum-frying as the processing technology and to explore the optimum processing conditions for vacuum-fried bamboo shoots. (2) To explore the changes of the quality and stability of the vacuum-fried bamboo shoots products during storage. (3) To evaluate the mutagenicity of soybean oils heated under vacuum or regular pressure for various periods toward Salmonella typhimurium TA100. In the optimization for vacuum-frying of bamboo shoots, results show that blanching in boiling water for 20 min reached the minimum water content and optimum texture while inhibited peroxidases sufficiently, that better dehydration rate and sensory scores were obtained in the spherical cross-sectional cutting of Makino’s bamboo shoots than the longitudinal cutting while the reverse is true for Ma bamboo shoots, and that to soak the cuts in 30 oBrix maltose solution for 2 hrs brought in an ideal dehydration effect. The optimum vacuum-frying conditions were found to be at 80 Torr vacuum, 94-98 oC frying temperature/25-28 min frying time for Makino’s bamboo shoots, and 101-103 oC frying temperature/23-25 min frying time for Ma bamboo by 2-variable 5-level surface response methodology experiments. In storage test, it shows the vacuum fried bamboo shoot products which packed in transparent bag can be stored up to 3 months under room temperature may maintain good quality. In Ames test for heated soybean oil, no mutagenicity on Salmonella typhimurium TA100 was found in the samples after 96 hrs heating no matter it was under vacuum or regular pressure. However, it retained better color under vacuum heating.