Enzymatic treatment of pineapple pomace and its application into fiber-rich biscuit making

Abstract

Pineapple pomace is a by-product of the pineapple juice industry. With high dietary fiber content, it has become a potential source added to fiber-rich foods in recent years. However, the ratio of soluble dietary fiber (SDF) to total dietary fiber (TDF) in pineapple pomace is very low while both SDF and insoluble dietary fiber (IDF) have positive effects on human health. In this study, the enzymatic treatment conditions of fresh pineapple pomace with commercial cellulase on its dietary fiber profile were investigated. The addition of non-enzyme-treated pineapple pomace (NTPP) and enzyme-treated pineapple pomace (ETPP) into biscuit formulation was then examined. The appropriate cellulolytic treatment conditions were the water content of 86 %, the cellulase concentration of 7.5 U/g dry matter, and the treatment time of 3 h, under which the SDF content was enhanced from 1.26 to 4.43 % while the SDF/TDF ratio was improved from 2.2 to 9.5 % as compared to those of NTPP. The use of NTPP or ETPP in biscuit formula increased TDF content and antioxidative capacities as well as hardness of the product. At the ratio of 30 %, the biscuits made with ETPP were lower in hardness, greater in SDF content, SDF/TDF ratio, antioxidative capacities, and overall organoleptic acceptance compared to the biscuits made with NTPP.