Evaluation of antioxidant activities of lotus rhizome root powder prepared by different drying conditions and its application to raw and cooked pork patties

Abstract

This study was to investigate the antioxidant activities of lotus rhizome root powders (LRRPs) prepared by different drying conditions and with different particle sizes, and the effect of LRRP on the physicochemical properties and shelf-life of raw and cooked patties. The total phenolic contents (TPCs) and total flavonoid contents (TFCs) of oven-dried LRRP (ODLRRP) at 100°C were higher than those of freeze-dried LRRPs (FDLRRPs) and ODLRRP at 60 or 80°C. TPCs, TFCs and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) values of LRRPs increased with increasing temperatures and decreasing particle sizes. The 2-thiobarbituric acid reactive substance (TBARS) values and volatile basic nitrogen (VBN) contents of raw patties with LRRPs added were decreased. Lightness, microbial counts of total bacteria and Enterobacteriaceae in raw patties, and the total bacterial counts of cooked patties with 1% ODLRRP at 100°C added were decreased. The redness of raw patties with FDLRRP added was increased, whereas the yellowness was increased by 100°C ODLRRPs addition. The color, TBARS, and VBN values of cooked patties with LRRPs added were decreased. The cooking process increased the TBARS and VBN but reduced microbial counts. Therefore, 1% 100°C ODLRRPs (< 150 μm) was effective in extending the shelf-life of raw and cooked patties during storage.