不同添加物對於藻藍蛋白飲品穩定性之影響

藻藍蛋白(phycocyanin, PC)為藍綠藻中輔助光合作用之可食用天然色素，經研究證實藻藍蛋白對人體具提高免疫力、抗癌、保護肝腎等效果，但其結構易受光、熱及環境酸鹼值的影響，因此增加藻藍蛋白穩定性成為一重要課題。本篇研究分成三部分，第一部分觀察藻藍蛋白在不同酸鹼條件下之熱穩定性，第二部分係使用四種添加物如糖類、多元醇、氯化鈉及抗壞血酸，加入藻藍蛋白飲品中，觀察對熱穩定之影響。第三部分則以最佳條件進行動力學和熱力學的分析。第一部分結果顯示，加熱對藻藍蛋白殘留率影響十分明顯，殘留率下降約13-39%，其外觀顏色和沉澱物含量對熱敏感性高，ΔE從26.24增加到52.91。若以pH 4.5-7.5樣品進行比較，則以pH 6.5者較為穩定。另外添加適當的糖類和多元醇可更有效的提升藻藍蛋白穩定性，最高可使藻藍蛋白殘留率達到控制組的2.3倍，其外觀顏色變化也有相似的趨勢。經由前述四大添加物的最適條件，進一步進行熱力學和動力學分析發現，隨著溫度的增加，藻藍蛋白色素裂解的化學反應越容易發生，另外，糖類添加可使色素半衰期延長2倍以上，同時也有較低的降解速率常數，其樣品活化能為80.10，遠高於控制組的60.77。此外，糖類的添加，使吉布士自由能有增加的趨勢，提高了藻藍蛋白裂解反應所需之門檻。綜合上述結果可知，四大類添加物以醣類對於藻藍蛋白穩定效果最為顯著。

關鍵字

藻藍蛋白；熱穩定性；添加物

並列摘要

Phycocyanin (PC) is a kind of nature pigment helping photosynthesis reaction in blue-green algae. There are studies confirmed that PC has anti-inflammatory, anti-cancer, nephroprotective, hepatoprotective and other functions to human body. However, its structure is easy to be denatured due to light, heat, pH value or other environment factors. Enhancing the stability of PC becomes an important issue. This research can be separated into three parts. Firstly, the best pH value (pH 4.5-7.5) in PC solution will be investigated with PC retention and L a b. Secondly, the stability of PC with the addition of sugar, polyol, sodium chloride and ascorbic acid were evaluated. In the end, kinetic and thermodynamic study were studied to elucidate the relationship between additive and PC stability. As the results, heat treatment influence PC retention obviously (ρ＜0.05), which decreased to 13-39%, and also sensitive in color appearance and precipitation percentage, which ΔE value is about 26.24-52.91. Comparing with pH 4.5-7.5 samples, it may be stabilized in pH 6.5. However, the addition of sugar and polyol can increase the stability of phycocyanin solution, which retention is 2.3 times greater than control group. There is also have the same trend in the appearance of phycocyanin solution. After the discussion of optimum species and concentration in four different additives, using kinetic and thermodynamic study to compare their PC stability. The result shows that the half-life of PC solution can be prolong 2.32-50 times comparing to control group in sugar addition sample, and it also gets lower degradation rate constant. The activation energy of sugar addition and control group are 80.10 and 60.77. The Gibbs free energy also increasing in the same time to enhance the threshold value of phycocyanin denaturation chemical reaction. In summary, sugar is the most effective additive with phycocyanin solution in these four additives.