Ultrasonic and hot air combined carrot drying method and ultrasonic and hot air combined drying device

Abstract

The invention discloses an ultrasonic and hot air combined carrot drying method and an ultrasonic and hot air combined drying device. The ultrasonic and hot air combined carrot drying method comprises the following steps of: (1) pretreatment of a carrot raw material, namely washing and slicing fresh carrots; and (2) ultrasonic and hot air combined drying, namely, putting carrot slices on a sieve, sequentially starting a heating and blowing device and an ultrasonic irradiation device, and carrying out ultrasonic and hot air combined drying on the carrot slices, wherein the drying temperature is 30-70 DEG C, the drying air speed is 0.3-3m/s, the ultrasonic power is 100-200W, the ultrasonic frequency is 20kHz, the distance between the ultrasonic irradiation device and the sieve is 5-15cm and the drying time is 3-6 hours. According to the ultrasonic and hot air combined carrot drying method, an ultrasonic technology is directly and effectively coupled to a hot air drying process, so that the heat transfer and mass transfer efficiencies in the drying process are improved, the drying time is shortened, the energy consumption is saved and the product quality is improved.

Description

technical field [0001] The invention belongs to the technical field of agricultural product processing, and in particular relates to a method for drying carrots with ultrasonic combined with hot air and an ultrasonic combined with hot air drying device. Background technique [0002] Carrots are rich in vitamins, sugar, starch, potassium, calcium, phosphorus, iron and other nutrients as well as inorganic salts and 5 kinds of essential amino acids, so they have high nutritional value and multiple health benefits. Among carrot processing methods, drying processing is the most common method. Drying process is to use the low water activity of the product to inhibit the growth and reproduction of microorganisms and the activity of enzymes, and at the same time, it can give the product a good flavor, so as to achieve the purpose of long-term storage, easy transportation and convenient consumption. [0003] As a main drying technology, hot air drying is widely used in food, especia...

AI Technical Summary

Problems solved by technology

However, it cannot be ignored that hot air drying also has some problems that need to be solved urgently, including: low heat and mass transfer efficiency, long drying time, high energy consumption, and low product quality

In order to improve the efficiency of hot air drying, it usually needs to be carried out at a higher drying temperature, which is very unfavorable to many heat-sensitive ingredients and physiologically active ingredients in food, and will easily lead to a decline in product quality, such as: loss of nutrients and aromatic substances, loss of functional ingredients Deactivation, surface hardening cracking, excessive shrinkage, low rehydration and noticeable color change; additionally significantly increases energy consumption

At the same time, the longer hot air drying process can easily cause the growth and reproduction of microorganisms, especially food spoilage.

Due to the above reasons, the use of hot air drying technology to dry carrots also has the following problems: 1) Too long drying time causes the carrots to fade in varying degrees; 2) High energy consumption; 3) A large loss of nutrients and flavor substances leads to rough taste and quality of carrots Difference

In the prior art, the patent CN101586905A discloses an ultrasonic hot air combined drying device, which includes a hot air generator, an ultrasonic generator, an ultrasonic probe, a material lifting table and an ultrasonic probe bracket. The drying quality of the material can shorten the drying time and improve the energy utilization rate. However, the device uses several ultrasonic probes arranged in a matrix. It can be lost in the form of heat; and the hot air generator is located on one side of the material lifting platform, the center height of the air outlet of the hot air generator is consistent with the height of the metal mesh surface, and the hot air blows to the material from one side, which cannot make full use of the heat energy of the hot air. Low efficiency and high energy consumption

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