Effects of different drying methods on the quality of daylily powder

Daylily is an edible flower in China. Daylily powder is prepared from the flowered or damaged by-products during its processing, which accounts for 10% of the total amount. In order to optimize the drying methods, the powder properties, internal structure, nutrition, and color of daylily powder prepared by natural air drying (ND), hot air drying (HD), vacuum freeze-drying (FD), and spray drying (SD) were studied and compared. The results showed that different drying methods had no effects on the internal structure of daylily powder. The diameter, bulk density, water holding capacity, oil holding capacity, and resting angle of daylily powder treated by four drying methods were significantly different. The nutrient indexes and color of daylily powder were significantly changed after different drying methods. HD prepared daylily powder can keep higher total protein, total sugar, and vitamin C; ND and FD prepared daylily powder had higher amino acid content and better flavor retention, while SD prepared daylily powder had smaller particle size, larger specific surface area, lighter color, and strong water and oil retention, which is more favorable for its use as a food additive. Compared with the other three methods, SD has obvious advantages and can be used as the optimal drying technology of daylily powder. The development and utilization of the waste daylily resources could be improved by using the pulverizing technology. This paper provided theoretical and technical support for the full utilization of daylily resources. The purpose of the study was to grow the daylily industry chain, Putting discarded daylily to comprehensive use. Novelty impact statement Powder processing is currently the best way to make full use of the abandoned damaged and flowered daylily resources and improves the added value.SD has obvious advantages and can be used as the optimal drying technology of daylily powder.