| Abstract: | 本研究將幾丁聚醣（Chitosan，CS，去乙醯度≧85%，607 kDa, Original Mw）以臭氧（O3）氧化降解至200-250 kDa（High Mw）、100-150 kDa（Medium Mw）及50 kDa（Low Mw）之分子量，配置2 mg/mL濃度之各種CS溶液並調整pH值至4.7，接著將不同濃度 （20-80 g/mL）之茄紅素溶液，與上述CS溶液混合均勻後，加入三聚磷酸鈉溶液（Sodium tripolyphosphate，TPP）使CS/TPP重量比為3/1、4/1、5/1及6/1，製備成幾丁聚醣-三聚磷酸鈉-茄紅素（CS-TPP-Lycopene）奈米顆粒，並探討茄紅素濃度、CS分子量及CS/TPP重量比對於CS-TPP-Lycopene奈米顆粒之包覆率、粒徑大小、表面電位及安定性（熱處理、儲存及胃腸道模擬）之影響，並利用掃描式電子顯微鏡（SEM）拍攝觀察此奈米顆粒外觀。 結果顯示，在包覆率方面，茄紅素濃度越高及CS分子量越大時，包覆率越好（41-71.4%），而CS/TPP重量比對包覆率無顯著影響（50-54.8%）；粒徑方面則隨茄紅素濃度、幾丁聚醣分子量及CS/TPP重量比之增加而粒徑會變大（634.4-1707 nm）；表面電位方面，隨幾丁聚醣分子量越小、CS/TPP重量比減少，表面電位會下降，但顆粒仍然皆帶正電荷（+33至+51 mV），而茄紅素濃度之影響不大。安定性方面，利用Medium Mw CS，茄紅素濃度80 g/mL及CS/TPP重量比3/1所製備出來的奈米顆粒，於120℃加熱處理1小時只損失8%之茄紅素；於25℃儲存28天後仍有47.4%之茄紅素保留率；於胃腸道模擬安定性試驗，將奈米顆粒置入模擬胃液（pH 1.2, with pepsin）2小時後，於模擬腸液（pH 7.4, with pancreatin）持續作用6小時，結果顯示茄紅素之累積釋放率低於1%。綜合以上實驗證實此奈米顆粒十分安定，並經由SEM觀察其顆粒型態為圓形球狀之奈米顆粒。
Chitosan (CS, original Mw 607 kDa, deacetylation ≧ 85%) use degraded by O3 oxidation into different molecular weights (High Mw 200-250 kDa, Medium Mw 100-150 kDa and Low Mw ≦ 50 kDa), then dissolved at a 2 mg/mL concentration adjusted to pH 4.7, and mixed individually with lycopene solution of different concentrations (20-80 g/mL). The mixed solutions were added dropwise with the sodium tripolyphosphate solution (TPP, pH 9.0) by different CS/TPP mass ratio of 3:1, 4:1, 5:1 and 6:1 to prepare CS-TPP-Lycopene nanoparticles. Such effective factors as lycopene concentration, chitosan molecular weight and CS/TPP mass ratio on the encapsulation efficiency (EE), particle size, zeta potential of the nanoparticles were investigate. SEM and stability (heat treatment, storage and gastrointestinal simulation) of the nanoparticles were also determined. As a result, a higher lycopene EE was obtained as the high lycopene concentration and CS Mw were applied (41-71.4%) EE was insignificantly affected by CS/TPP mass ratio (50-54.8%). CS-TPP-Lycopene nanoparticles size increased as CS Mw, lycopene concentration and CS/TPP mass ratio increased (634.4-1707 nm). Zeta potential of CS-TPP-Lycopene nanoparticles increased as CS Mw and CS/TPP mass ratio increased (+33-+51 mV), lycopene concentration showed a little effect . Heat stability of CS-TPP-Lycopene nanoparticles (prepared with medium Mw CS (128 kDa), lycopene concentration of 80 g/mL and CS/TPP mass ratio of 3/1) at 120℃ for 1 hour showed a reducing about 8% loss of the lycopene. Storage stability of CS-TPP-Lycopene nanoparticles at 25℃ for 28 days was still 47.4% of the lycopene retention. Simulated gastrointestinal stability was carried out by mixing the CS-TPP-Lycopene nanoparticles in the simulated gastric fluid (pH 1.2, with pepsin) for 2 hours and then in the simulated intestinal fluid (pH 7.4,with pancreatin) for 6 hours, that showed a less than 1% of lycopene release. SEM observation showed that both CS-TPP and CS- TPP-Lycopene nanoparticles were spherical shape. |
