A kind of preservation method of roselle

Abstract

The invention discloses a fresh-keeping and preservation method of roselle. The calyx of roselle is washed and drained of surface water, placed in a superheated steam environment of 135-140°C for 15-20min, and then the calyx is heated at 70-80°C. The hot air was dried for 20‑30min, and the calyx was naturally cooled and then frozen for preservation. The present invention adopts the combination technology of superheated steam drying and hot air drying to treat the roselle flower. The superheated steam has good heat transfer performance, the calyx is evenly heated, and the shape of the calyx can be better maintained. At the same time, due to the superheated steam drying without oxidation reaction, the color of the calyx will not change. Fading, so the drying quality is good. On the basis of keeping the shape and color of the calyx to the maximum extent, the present invention continues to use hot air to dry to reduce the moisture in the calyx, and then the roselle after freezing preservation can maintain a better fresh state, has strong rehydration ability, and can be preserved one year.

Description

technical field [0001] The invention relates to the technical field of preservation of fresh flowers, in particular to a method for preservation of roselle flowers. Background technique [0002] Roselle, also known as roselle and Sudan red, is a plant of the genus Hibiscus in the family Anemoneaceae. It is valuable as a food raw material, natural pigment, and medicinal. Its calyx, seeds, and leaves can be used. Fresh roselle has high water content and is easy to rot and deteriorate. The storage period is only a few days. Most of the existing methods for preserving roselle are to dry it, that is, directly air-dry or hot-air-dry to remove most of the moisture contained in the calyx, and then seal and preserve the obtained dried roselle. Although this hot-air drying method can remove most of the water in the roselle and prolong its storage period, it has obvious shortcomings: First, the heat transfer characteristics of hot-air drying will cause the calyx to be heated unevenly,...

AI Technical Summary

Problems solved by technology

Although this hot-air drying method can remove most of the water in the roselle and prolong its storage period, it has obvious shortcomings: First, the heat transfer characteristics of hot-air drying will cause the calyx to be heated unevenly, and the drying progress will be delayed. Destroy the morphological structure of the calyx, and its integrity cannot be preserved; second, the surface of the calyx will change color easily if the temperature is too high or too low, destroying its original color, and it will also consume a lot of energy, which is not conducive to energy saving; third, The roselle flower preserved by hot air drying has poor rehydration performance, long rehydration time, light color of rehydration, and low leaching rate of water-soluble anthocyanins

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