Microencapsulation of green tea polyphenols and its effect on incorporated bread quality

Green tea polyphenols are potential antioxidants, anti-carcinogenic and effective against various degenerative disorders. Polyphenols are more sensitive to high temperature and alkaline pH. To improve the stability of polyphenols, green tea extract was microencapsulated by freeze drying and spray drying technique using three different wall materials such as maltodextrin (MD), beta-cyclodextrin (CD) and combination of both (MD CD). Freeze dried encapsulates exhibited higher encapsulation efficiency (60 -76%) and antioxidant activity (IC50 value 54.77-60.26 mu g/ml) than spray dried encapsulates. Comparatively, MD encapsulates had higher encapsulation efficiency and antioxidant activity than other encapsulates. Hence spray dried and freeze dried MD encapsulates were incorporated into bread and evaluated for their quality characteristics. Green tea extract and encapsulates incorporated bread retained their quality in terms of volume and crumb firmness and almost similar to control. Moreover, there was not much significant difference on total polyphenol content of green tea extract and microencapsulates incorporated breads. (C) 2015 Elsevier Ltd. All rights reserved.