蛋白質水解物藉由flavourzyme、alcalase、trypsin、chymotrypsin和pepsin等酵素分別水解分離大豆蛋白(ISP)12 h而製備出來，每一種水解物均測定其回收率與評估其在Caco-2細胞中的相對膽固醇吸收率(RCU, %)，回收率愈高代表水解物的產率愈高，而RCU愈低顯示水解物對細胞的膽固醇吸收抑制效果愈高，結果指出ISP藉由上述任何一種酵素的水解均可進一步降低細胞的RCU，其中以flavourzyme-ISP水解物具有最低的RCU為37%，並可維持最高的回收率達58%。ISP經Flavourzyme的限制性水解對其回收率與RCU的影響也被探討，限制性水解以水解率(DH, %)來表示，當DH小於22.8%時，隨著DH的增加其RCU有降低的趨勢，然而延長水解使DH超過28%時，並未能保證其膽固醇吸收抑制的增強效果，但卻顯著的 (p < 0.05) 降低水解物的回收率。根據穿透式電子顯微鏡對膠微粒的檢視可清楚地發現水解物被併入膠微粒的膜中但ISP卻不能，此發現建議水解物的併入導致膠微粒製備時減少膽固醇的溶解度以及抑制Caco-2細胞對膽固醇的吸收。

Protein hydrolysates were produced by hydrolyzing isolated soy protein (ISP) with enzymes including flavourzyme, alcalase, trypsin, chymotrypsin and pepsin for 12 h, respectively. Each hydrolysate was measured its recovery and evaluated its relative cholesterol uptake (RCU, %) in Caco-2 cells. The higher the recovery represented the higher the yield. The lower the RCU revealed the higher the cholesterol absorption
inhibition. The result indicated that intact ISP could further decrease its RCU by hydrolyzing with any of these enzymes. Flavourzyme-ISP hydrolysate had the lowest RCU of 37% and maintained the highest recovery
of 58% than the others. The effects of limited ISP hydrolysis using flavourzyme in terms of the degree of hydrolysis (DH, %) on recovery and RCU in Caco-2 cells were also investigated. When the DH was less than
22.8%, the RCU decreased with the increase in DH. However, extensive ISP hydrolysis using flavourzyme to obtain DH higher than 28% did not guarantee enhance the cholesterol absorption inhibition but significantly
(p < 0.05) decreased the recovery. According to micelle inspection using a transmission electron microscope,the hydrolysate was clearly incorporated into the micellar membrane but ISP wasn’t. This finding suggested that incorporation of the hydrolysate lead to reduce cholesterol solubility during micelle preparation as well as
inhibit cholesterol absorption in Caco-2 cells.