Abstract: The effects of three drying methods including vacuum freeze-drying, natural drying in the shade and hot-air drying were investigated on the nutritional composition, amino acid composition and volatile flavor components of Elaegnus angustifolia flowers. The results indicated that E. angustifolia flowers dried by various drying methods demonstrated significant differences in terms of nutritional components and volatile flavor components. Hot-air drying brought about a significant reduction in the contents of reducing sugar, protein and total amino acids in E. angustifolia flowers than did the two other drying methods (P < 0.05). The contents of total amino acids and total phenols and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity in the vacuum freeze-dried sample were significantly higher than those in the samples dried by the other methods (P < 0.05). Hot air drying caused the maximum loss of flavor amino acids in the flowers, thereby lightening the umami and sweet tastes. The proportion of essential amino acids in the flowers, close to that needed by human body, was nearly independent of the drying methods. Electronic nose analysis showed significant differences in volatile flavor components among flower samples dried by different methods. The volatile flavor components of the samples dried by vacuum freeze drying and natural drying were more similar to those of fresh flowers. The vacuum freeze dried sample had the best quality and flavor. Taking into account both economy and drying efficiency, natural drying in the shade was also more suitable for E. angustifolia flowers. The results of this study provide a theoretical basis and practice rationale for the development of drying techniques for E. angustifolia flowers to develop new products.

Key words: drying methods; Elaeagnus angustifolia flowers; quality; electronic nose; volatile aroma components