Valorization of asparagus-leaf by-product through nutritionally enriched chips to evaluate the effect of powder particle size on functional properties and rutin contents

Abstract

This study first observed that the nutritional and phytochemical contents in asparagus leafy by-product were comparable or higher than those in edible portion. The extractable rutin in leaf was found to increase with a decrease in powder particle size (400–120 μm), as indicated by ultra-performance liquid chromatographic analysis. Then, such leaf powders of different particle sizes were incorporated into freeze-dried chips formulation to evaluate the effect on chips properties. There was an apparent higher retention of total chlorophylls (161%), total phenolic (46%), and total flavonoid (79%) due to the decrease in particle size, ultimately showing an increase in the antioxidant activities. Also, the color (L*, a*, and b* values) was significantly difference (p < 0.05). LF-NMR study indicated the status of water and safer level of drying (a w = 0.6). Conclusively, samples containing finer asparagus powder showed higher nutritional and phytochemical contents than those made with coarser powder.