不同去乙醯度膠態幾丁聚醣乳化性之研究

Emulsifying Properties of Different Deacetylated Colloidal Chitosans

閻立平(Li-Pyng Yan) ； 柯建邦(Chien-Pang Ko) ； 孫百秀(Pai-Hsiu Sun) ； 阮進惠(Jin-Hwei Rwan)

《臺灣農業化學與食品科學》 48卷1期 (2010/02) Pp. 1-10

https://doi.org/10.6578/TJACFS.2010.001

摘要

本研究將幾丁質製備為不同去乙醯度之幾丁聚醣，並以12 N HCl處理二小時製備30-40、60-70及＞85%去乙醯度之膠態幾丁聚醣(colloidal chitosan)後，測量其分子量及以掃描式電子顯微鏡(SEM)觀察其內部結構，並將上述膠態幾丁聚醣作為乳化劑，於不同濃度（0.5、1.0、1.5、2.0、及3.0%）及pH（3.0、4.0、5.0及6.0）下乳化，比較其乳化能力。上述乳化液分別於5、25、60、100和121℃下各處理30分鐘，除5℃之處理組繼續貯存於5℃，其餘各組均在25℃下貯存二星期，貯存期間以肉眼觀察是否有油水分離現象。此外，將較安定之乳化液進行凍結－解凍五次並觀察其安定性，同時以位相差顯微鏡觀察上述處理乳化液之乳滴(emulsion droplets)大小之改變。結果發現，膠態幾丁聚醣之去乙醯度越高，其分子量越小；膠態幾丁聚醣內部為多孔性結構，但去乙醯度大於85%時，內部結構呈現嚴重破損。在乳化能力方面，膠態幾丁聚醣之最適乳化濃度為1-2%及pH6.0。於適當濃度及pH值下乳化，30-40、60-70及＞85%去乙醯度者之乳化能力分別約350、450及400 mL oil/100 mL chitosan solution。在乳化安定性方面，60-70%去乙醯度者最為安定，於濃度1-1.5%及pH 6.0下乳化，其乳化液於5-121℃下處理後雖乳滴直徑隨著處理溫度增加而變大，但於25℃貯存，二星期均未發生油水分離。此外，此乳化液經五次凍結－解凍後，其乳滴直徑漸漸變大但仍維持安定狀態。

關鍵字

去乙醯度 ； 膠態幾丁聚醣 ； 乳化性質加熱處理 ； 凍結解凍處理

並列摘要

Colloidal chitosans with different degrees of deacetylation (30-40, 60-70 and ＞ 85%) were prepared by treating chitosans with 12 N hydrochloric acid for 2 hours. The colloidal chitosans were determined on molecular weight and observed internally by scanning electron microscope (SEM). Emulsifying capacities of the colloidal chitosans were carried out at different concentrations (0.5, 1.0, 1.5, 2.0 and 3.0%) and pHs (3.0, 4.0, 5.0 and 6.0). Their emulsifying stabilities were determined by preparing emulsions at the above concentrations and pHs, then individually being treated at 5, 25, 60, 100 and 121℃ for 30 min. They were stored at 25℃ for 2 weeks except that the one treated at 5℃ remained kept at 5℃ . The emulsion showed the best stability was followed by freeze-thawing for 5 cycles. The droplet size of the treated emulsion was also observed with a phase-contrast microscope. As results, the colloidal chitosans with higher deacetylation had lower molecular weight. The internal structures of these deacetylated chitosan were porous, and were seriously damaged while the deacetylation was higher than 85%. The colloidal chitosan solution of concentrations of 1.0 to 2.0% and pH 6.0 gave a good emulsifying capacity. The emulsifying capacities of the colloidal chitosans with 30-40, 60-70 and ＞ 85% deacetylation were about 350, 450 and 400 mL / 100 mL chitosan solution. The 60-70% deacetylated chitosan emulsified at a concentration of 1-1.5% and pH 6.0 gave a relatively stable emulsion after treating at different temperatures (5 to 121℃) and with the freeze-thawing cycle for 5 times. We also noted that the diameters of the emulsion droplets increased with increasing the treatment temperature and with increasing the cycle of freeze-thawing treatment.

並列關鍵字

colloidal chitosans of different deacetylation degrees ； emulsifying properties ； heating treatment ； freeze-thawing treatment