本研究目的為探討儲存過程中硫酸鈣豆腐蛋白質與水分子狀態及質地特性之 變忱。豆腐製價是利用硫酸鈣作為凝結劑，凝膠完成後進行破碎並置於模板以重物 下壓，濾、出乳清，從模板取出後即為硫酸鈣豆腐成品。將豆腐儲存於40 C 冰箱中， 分別於卜3 、5 和7 天取出進行分析。豆腐水分子狀態分析採用離心方法，蛋白質 狀態分析採用應力鬆拙和潛變試驗，並觀察豆腐微結構之變忱。實驗結果顯示，豆 腐離水量隨儲存天數增加而增加。以離心方式區分的expressible water 和entrapped water 於豆腐儲存過程中無明顯變忱。而豆腐網狀結構於第7 天發現孔洞有增加的 現象。藉由three-element Maxwell 模型轉換應力鬆強曲線所獲得的鬆抽時間參數， 可將豆腐網狀結構中蛋白質分子狀態區分為三個部分(λ1 、λ2 、λ，3) ， λ1 狀態為靠近網 狀結構孔洞處，為水和脂質與蛋白質等鍵結處之狀態; À3 狀態為網狀結構結合區 Gunction zone)之兼具連續相及非連續相的層片狀態;λ2 狀態則介於λ1 和b 狀態之 間。儲存天數增加，豆腐b 值上升幅度增大，表示蛋白質分子有重排現象，且豆 腐結構異質性增加，導致離水量增加。因此，應力鬆?也實驗得到的蛋白質狀態和離 心方式得到的水分子狀態以及微結構觀察可幫助了解豆腐儲存過程質地的變他情 形。

The objective of this research was to investigate the changes of the states of protein and water of calcium sulfate tofu during storage. Tofu was made by using calcium sulfate as coagulant. After gelation, the curds were broken and pressed in a mold to express the whey. Tofu was stored at 4oC in the refrigerator and samples were used for analysis at 1, 3, 5, and 7 days. The state of water in tofu was analyzed by the centrifugation method, and the state of protein in tofu was studied by the stress relaxation test and creep test. The results showed that, there were no obvious changes in the amount of expressible water and entrapped water in tofu which were classified using centrifugation method during storage. Changes in the microstructure of tofu were also observed. The holes in tofu matrix increased after 7 days of storage. The state of protein in tofu could be classified into three fractions (λ 1,λ2, and λ3) using the relaxation times transferred by three-element Maxwell model from stress relaxation curve. The λ i state represents water, protein, and fat located near the holes of the tofu matrix. The λ 3 state represents both the continuous phase and discrete phase located in the matrix junction zones. The λ2 state located in between λ 1 and λ3 states. The value of λ 3 in tofu increased during storage indicating the rearrangement of proteins in tofu matrix occurred and the heterogeneity of tofu increased. However, the rearrangement of protein during storage resulted in the increase of syneresis of tofu. The states of protein and water obtained by stress relaxation and centrifugation methods, respectively, and the microstructure observation could be used to study the mechanism of the changes in the texture of tofu during storage.