利用幾丁聚醣水解物為凝固劑製備中式豆腐

Using Chitosan Hydrolysates as Coagulants for Preparing Chinese Tofu

阮進惠(Jin-Hwei Rwan) ； 陳俊豪(Chun-Hau Chen)

《臺灣農業化學與食品科學》 44卷1期 (2006/02) Pp. 54-62

https://doi.org/10.6578/TJACFS.2006.007

摘要

將生豆漿加熱至不同溫度及時間後，冷卻至不同溫度並立刻加入不同水解度之幾丁聚醣水解物至不同濃度以凝固生豆漿中之蛋白質，藉此可找出適合加熱處理溫度和時間及凝固溫度以及適合濃度之各個幾丁聚醣產品，以達到最佳蛋白質之凝固率。根據以上之結果，以不同水解度之幾丁聚醣水解物為凝固劑製備各種豆腐並比較其產率、蛋白質回收率、保水性、物性和官能評估。最後，在這些幾丁聚醣產品中，選出一種具可製備出呈現上述各項優良性質之豆腐為凝固劑，加入κ-carrageenan或sodium alginate製備豆腐並比較其產率、保水性及官能評估。此外，亦依傳統以CaSO4為凝固劑製備豆腐為對照比較。結果發現，生豆漿加熱處理之溫度為98~100℃，在此溫度保持10 min後冷卻至75℃可達到最佳的蛋白質凝固率，水解度愈高之幾丁聚醣水解物及其添加濃度愈高即可得愈高之蛋白質凝固率。以上述各種幾丁聚醣產品為凝固劑，添加至2 g/L製備各種豆腐時：在豆腐產率方面，以30%水解度者為佳，約36.5g tofu/100 mL soymilk；蛋白質回收率方面，以0%水解度者最差，約73%，而其他水解度者均在90~92%間；水分含量方面，剛製出豆腐時以0%水解度者水分比其他組稍高，約87%，但置放時很快出現嚴重離水現象，其他組之水分約85%；在質地測試方面，隨著水解度之增加，豆腐之硬度(hardness)、黏著性(adhesiveness)、彈性(springiness)、內聚性(cohesiveness)及咀嚼性(gumminess)均有下降趨勢；而在感官評估方面包括外觀、風味、口感及整體性則以添加20%水解度之豆腐較佳。此外，以20%水解度者為凝固劑，添加濃度2g/L製備豆腐時，加入0.5g/L κ-carrageenan則可提高豆腐之產率及水分含量，而與傳統以CaSO4為凝固劑製備豆腐相較，前者官能評估之總接受性亦稍高些。

關鍵字

不同水解度之幾丁聚醣 ； 凝固劑 ； 中式豆腐

並列摘要

Firstly, optimal conditions such as heating treatment (heating temperature and time) of soymilk, coagulation temperature and concentrations of chitosan hydrolysates were determined to obtain the highest protein coagulation from soy milk. Secondly, tofu samples were prepared by coagulating the heated soymilk with chitosan hydrolysates of different degrees of hydrolyzation. These samples were then compared on their product yield, texture profile, protein recovery, moisture content and sensory evaluation. Tofu was also treated κ-carrageenan or sodium alginate to improve the yield and moisture content. A conventional tofu (CaSO4 as a coagulant) was made as a control for sensory evaluation.
As a result, the treatment of heating soy milk at 98~100℃ for 10 min, then cooling to 75℃ before coagulation by a chitosan hydrolysate was suitable. The higher hydrolyzation degree of the chitosan and concentration, the higher protein coagulation. The 30% hydrolyzed chitosan gave a highest tofu yield, about 36.5 g/100 mL soymilk. The chitosan hydrosates gave a protein recovery of about 90~92% while the 0% hydrolyzed chitosan showed lowest, about 73%. The 0% hydrolyzed chitosan treated tofu had a moisture content of 87% higher than the others, about 85%, but showed remarkably a water separation. The higher hydrolyzation degree of the hydrolysate caused the lower hardness, adhesiveness, springiness, cohesiveness and gumminess. On the sensory evaluation, the tofu treated with the 20% hydrolyzed chitosan showed the highest scores on all items including appearance, flavor, mouthfeel and acceptability. The addition of κ-carrageenan at a concentration of 0.5 g/L into the 20% hydrolyzed chitosan treated tofu gave a higher tofu-yield, and higher moisture content and its sensory evaluation was slightly higher than that of the conventional tofu.

並列關鍵字

Chitosan of different degree of hydrolyzation ； Coagulant ； Chinese tofu