Fiber concentrates from asparagus by-products: Microstructure, composition, functional and antioxidant properties

ABSTRACT The by-product of asparagus processing has a high content of nutrients and bioactive compounds. Based on this, it becomes interesting to investigate treatment options to obtain a product with better nutritional quality, avoiding its waste and environmental impact. The aim of this study was to produce and characterize fiber concentrates from asparagus by-products. Water extraction treatments were realized in homogenizer (H), water bath (B), shaker (S) and ultrasound (U). One sample was not submitted to water extraction (control). All the products obtained were dried and milled before the characterization analysis. In relation to color, the concentrates obtained by U, H and S treatments had the highest luminosity (66.5 to 69.8). The index of water and oil absorption of the fiber concentrates ranged from 11.8 to 14.7 (g g-1) and 6.1 to 8.9 (g g-1), respectively. The analysis of scanning electron microscopy showed the effect of processing in the fibers present in the concentrates. The control had the highest content of ash (6.4 g 100 g-1), proteins (11.4 g 100 g-1), and reducing sugars (3.4 g 100 g-1), due to the water extraction realized in the other samples. The fiber concentrate obtained by ultrasound had the best proportion of soluble fiber to insoluble fiber and antioxidant potential similar to the control, so, among the treatments tested it is the most recommended to the formulation of functional food products.