Functional properties, bioactive compounds, and in vitro gastrointestinal digestion study of dried fruit pomace powders as functional food ingredients

Apple (AP), blueberry (BP), red raspberry (RP), and cranberry pomace (CP), were evaluated for their physicochemical and functional properties and bioactive compounds (i.e. dietary fibers and phenolics) as potential functional food ingredients. Bound phenolics in AP, BP, and CP could be liberated through simulated gastrointestinal digestion (SGD). Among all tested fruit pomace (FP), RP contained the highest total phenolic content based on both chemical extraction and SGD. AP contained the highest soluble dietary fiber obtained from AOAC method and SGD, while it presented the lowest insoluble dietary fiber in comparison with BP, RP, and CP. Total dietary fiber content of RP and CP from SGD was significantly (P < 0.05) higher than that from AOAC method. AP exhibited a high water-holding capacity (9.27 g water/g dry weight (DW)) and swelling ability (6.51 mL/g DW), while BP and CP showed high oil-adsorption capacity (1.96 g oil/g DW and 1.97 g oil/g DW, respectively). The differences in the functional properties of the tested FP could be due to their distinguished fiber compositions and structures. This study demonstrated the potential of using FP as fiber-rich and antioxidant functional ingredient that can be selectively utilized in various food applications. (C) 2017 Elsevier Ltd. All rights reserved.