Comparison of the Nutritional Components and Antioxidant Activity in Aruncus dioicus var. kamtschaticus with Different Drying Methods

Abstract

The purpose of this study was to compare the effects of two drying methods (hot air drying [HAD] or vacuum freeze drying [FAD]) on the physicochemical components and antioxidative activities of Aruncus dioicus var. kamtschaticus powder. The crude fat content in the FAD was higher than that in the HAD. There were no significant differences in the proximate compositions, such as contents of moisture, crude ash, crude protein, and carbohydrates, depending on the drying methods. The total amino acid and essential amino acid contents were significantly higher in FAD than in HAD. The valine, phenylalanine, lysine, histidine, aspartic acid, asparagine, glutamic acid, arginine, ornithine, and γ-amino-n-butyric acid (GABA) contents in FAD were higher than in HAD, while the serine, phosphoserine, proline, glycine, alanine, tyrosine, and taurine contents in HAD were higher than in FAD. There were no significant differences in saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acid contents based on the drying methods. The most abundant fatty acid in the FAD was linolenic acid, and the linolenic acid content was approximately the same, regardless of the drying method used. The contents of malic acid and total organic acids in the FAD were higher than in the HAD, while the content of succinic acid was higher in the HAD than in the FAD. Vitamin C and E contents in HAD were higher than those in FAD. The total polyphenol and total flavonoid contents, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino- bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activities of the FAD sample were higher than those of the HAD sample. These results indicate that vacuum freeze drying is a better drying method for preserving the nutritional components and antioxidative activities. These study results may provide the basic data for follow-up studies seeking a better understanding of the functional properties of the FAD powder.