Investigation of antioxidant and sensory properties and in vitro bioaccessibility of low-fat functional cookies substituted with wheat germ flour and coffee silverskin

Abstract

BACKGROUND: This study aimed to produce new functional cookies with high nutritional properties and low calorie content. It investigated the effects of incorporating wheat germ flour (WGF) at levels of 10–30% as a substitute for whole wheat flour (WWF), along with coffee silver skin (CSS) in the same proportions, serving as natural functional additives to substitute for fat in cookie formulations. RESULTS: The total phenol content of the cookies with added WGF-CSS ranged from 1813.72 to 1838.45 mg gallic acid equivalent (GAE) per kilogram of dry weight (mg GAE kg−1), whereas the total phenolic bioaccessibility values ranged between 53.39 and 56.84%. Of the three methods used to determine antioxidant capacity (AC), the cupric reducing antioxidant capacity (CUPRAC) method gave higher bioaccessibility values (44.55–51.19%) than the 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation and 2,2-diphenyl-1-picrylhidrazyl (DPPH) scavenging methods. The contribution of WGF-CSS supplemented cookies to the recommended dietary allowances (RDA) (%) of K, P, Mg, and Ca increased depending on the number of cookies consumed and the WGF and CSS ratio. The general acceptability scores of the cookies varied between 5.66 and −7.08, and the 10% WGF cookie (F2) (6.48) sample received the score that was closest to that of the control. Moderately strong positive relationships (r > 0.90, P < 0.05) were detected between the physicochemical and sensory characteristics of the cookies. CONCLUSION: As a result, WGF and CSS food additives with high nutritional properties can be recommended as potential enriching ingredients and fat substitutes in the development of new products in the functional food industry. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.