Blueberry by-product as a novel food ingredient: physicochemical characterization and study of its application in a bakery product

Abstract

BACKGROUND: Industrial blueberry juice processing results in a significant amount of by-product, the so called pomace, which could represent a nutritionally valuable source of fibre and bioactive compounds to enhance either technological or nutritional characteristics of foods. The aim of this study was to obtain novel ingredients based on blueberry by-product, applying different drying methods: convective (CD), freeze drying (FD) and vacuum drying (VD). The powders were physicochemically, functionally and nutritionally characterized. Finally, its application to formulate muffins in replacing 10–20–30% of wheat flour was studied to evaluate the effect on textural, colour and sensorial characteristics. RESULTS: CD reduced the hydration and functional properties when compared to FD and VD. The powders were characterized by a high content of dietary fibre (273 ± 5 g kg−1) and good retention and bioaccessibility of antioxidant compounds (39–85% range). The powder addition to formulate muffin decreased lightness and chromaticity, without differences due to the drying process. The texture parameters were reduced with 10% of ingredient addition; meanwhile, 20–30% showed similar values to the muffin control. Sensorial evaluation presented good overall acceptability (>6 ± 2 on a 9-point hedonic scale) and some specific attributes showed a significant drop in overall acceptability, recommending its optimization according to penalty analysis. CONCLUSION: These results suggest that functional ingredients rich in fibre and bioactive compounds may be obtained from an industrial by-product, giving added value and avoiding or reducing their loss; this could also be a promising vehicle to incorporate dietary fibre and bioactive compounds into bakery goods.