本研究由廢蠶繭萃取、純化並製備不同分子量之蠶絲絲膠蛋白，同時探討不同分子量蠶絲絲膠蛋白之抗氧化性與抑制酪胺酸酶之能力。結果顯示，經由超過濾濃縮所獲得不同分子量之蠶絲絲膠蛋白對清除DPPH(2,2-diphenyl-1-picryl-hydrazyl)自由基、清除ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)陽離子自由基、抑制酪胺酸酶能力普遍具有效果，其中以分子量為100 kDa之蠶絲絲膠蛋白效果最佳，在濃度為25 mg/mL時清除 DPPH 自由基能力已達 90.52%，清除 ABTS 陽離子自由基能力已達 91.06 %，而抑制酪胺酸酶能力為 84.04%，若在100 mg/mL下DPPH自由基清除能力達95.37%、清除 ABTS 陽離子自由基能力達 94.01%，抑制酪胺酸酶能力達 94.72%。在奈米乳化方面，結果顯示不同分子量蠶絲絲膠蛋白與荷荷巴油形成奈米乳化液、奈米乳化活性及奈米乳化安定性之效果佳。不同分子量蠶絲絲膠蛋白在不同濃度下，以5 kDa 蠶絲絲膠蛋白之奈米乳化液粒徑最小，若在50 mg/mL奈米乳化液之粒徑為 83.7 nm、奈米乳化活性能力為 99.4%。5 kDa 蠶絲絲膠蛋白在50 mg/mL、 pH 5.5與荷荷芭油所形成奈米乳化液之粒徑會隨高壓均質處理次數而改變，經 3 次處理可得為最小粒徑約28.1nm。本研究顯示蠶絲絲膠蛋白具有高抗氧化性及抑制酪胺酸酶之活性，同時可與荷荷巴油形成奈米乳液，應能易於皮膚吸收，因此極有潛力將蠶絲絲膠蛋白活性成分製作高活性美白及易吸收之化妝品，極具經濟價值。

The aim of this study was to develop a sample preparation protocol for extracting silk protein (sericin) and to examine the feasibility of its inhibition of free radical and melanin formation as well as the preparation of its nanoemulsion. Various molecular weights of sericin were observed at different concentrations regarding its 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation scavenging activity. In addition, its inhibition of tyrosinase was also studied. For sericin of different molecular weights that was obtained after fractionation by ultrafiltration, the DPPH scavenging activity, ABTS cation scavenging activity, and tyrosinase-inhibiting activity was observed. However, sericin of 100 kDa showed the highest levels of activity; at a concentration of 25 mg/mL, the scavenging activity of DPPH free radicals and ABTS cation free radicals reached 90.52% and 91.06% capacity, respectively, whereas the tyrosinase inhibition reached 84.04% capacity. At 100 mg/mL, the scavenging activity of DPPH free radicals and ABTS cation free radicals was 95.37% and 94.01%, respectively, whereas the tyrosinase inhibition capacity was 94.72%. Furthermore, when mixed with jojoba oil, the sericin of different molecular weights formed nanoemulsions that displayed excellent activity and stability. The minimum particle size could be obtained when sericin with a molecular weight of 5 kDa was applied at a concentration of 50 mg/mL; the resulting particle size was 83.7 nm, and the nanoemulsifying capacity was 99.4%. The size of nanoemulsions varied by the number of high-pressure homogenization treatments. When 5 kDa sericin was mixed with jojoba oil at 50 mg/mL and pH 5.5, the minimum diameter of 28.1 nm was obtained after three treatments. This study demonstrated that sericin has high antioxidation and tyrosinase-inhibition ability. When mixed with jojoba oil, nanoemulsions may form, which might be easily absorbed through the skin. Therefore, the active component of sericin has potential for use as an ingredient in the production of whitening cosmetics that have high activity and may be easily absorbed.