Method for producing dehydrated vegetables by puffing with superheated steam

Abstract

The invention relates to a method for producing dehydrated vegetables by puffing with superheated steam. The method comprises the following steps of: chopping picked and cleaned vegetables, performing color-fixing treatment and then coating, pre-dehydrating, heating with superheated steam and introducing compressed air for increasing pressure and puffing, drying and then quickly cooling with air,and packaging to obtain dehydrated vegetable products. By the adoption of the coating treatment, water absorption of vegetables and non-uniform puffing can be avoided in the superheated steam puffingprocess. After vegetables are heated by superheated steam, the air is introduced to increase pressure to improve puffing pressure difference, so as to effectively reduce the temperature required for puffing vegetables with superheated steam and prevent the problems of texture softening and nutrient loss caused by overheating. Vacuum drying is applied to the pre-dehydrating and drying treatments, so that the dehydration speed is increased and the change of vegetable color is reduced. The quick air-cooling treatment avoids moisture absorption and moisture regain of dehydrated vegetables. The method has the advantages of simple process, low puffing temperature, low energy consumption and the like, can significantly improve the rehydration property of dehydrated vegetables, and can be widely applied to the processing of different types of dehydrated vegetables.

Description

technical field [0001] The patent of the invention relates to the field of food processing, in particular to a method for producing dehydrated vegetables by superheated steam puffing. Background technique [0002] Dehydrated vegetables, also known as rehydrated vegetables, are made by washing, cutting and drying fresh vegetables to remove most of the water in the vegetables. Dehydrated vegetables have the advantages of easy storage and transportation, light weight, and convenient consumption. High-quality dehydrated vegetable products should not only have good color, but also have good rehydration performance to meet the requirements of vision and taste. At present, sun-dried, hot-air dried, and freeze-dried methods are often used to produce dehydrated vegetables. Drying is greatly affected by climate and environmental conditions, the dehydration time is long, and the sanitation is poor. Due to the serious shrinkage of vegetables during the drying process, the rehydration ...

AI Technical Summary

Problems solved by technology

However, superheated steam usually entrains water. When superheated steam acts on vegetables, it will also produce condensed water due to heat exchange. When vegetables absorb more water, it will seriously affect the puffing effect; the effect of superheated steam for a long time will make the temperature of vegetables too high and cause it The occurrence of soft rot not only affects the puffing effect but also easily leads to the loss of vegetable nutrients

Furthermore, the temperature of dehydrated vegetables produced by thermal processing methods such as hot air drying is relatively high, and they are usually packaged after natural cooling. The cooling process will easily cause dehydrated vegetables to absorb moisture in the air and regain moisture.