CN102406220B - Quick drying method of hericium erinaceus - Google Patents

Abstract

The invention relates to a method for rapidly drying Hericium erinaceus, and the method comprises the following steps: selecting Hericium erinaceus, drying with hot air once, treating with low-frequency microwaves, drying with hot air twice, packaging and storing the dried Hericium erinaceus. The invention reasonably combines hot air drying and low-frequency microwave treatment, can obviously improve the drying rate of Hericium erinaceus, and can obviously reduce drying energy consumption. Because low-frequency microwaves are extremely penetrating, even though Hericium erinaceus is large in size, it can still heat the inside and outside at the same time, and can accelerate the migration of water from the inside to the outside under the condition of low power density. Low-frequency microwave treatment replaces the necessary humidity equalization process in traditional hot air drying, which can save a lot of time and improve production efficiency. Moreover, the tissues of Hericium erinaceus treated with low-frequency microwaves have micro-expansion, which can speed up the drying rate of hot air in the later stage.

Description

A kind of method for rapid drying of Hericium erinaceus

technical field

The invention relates to the technical field of food drying and processing, in particular to a method for rapidly drying Hericium erinaceus by using hot air drying and low-frequency microwave treatment.

Background technique

Hericium erinaceus belongs to the fungus of the family Odontophyceae. There are hairy spines on the surface of the mushroom cap, about 1 to 3 cm long. The fruiting body is round and thick, white when fresh, light yellow to light brown after drying, and 3.5 to 10 in diameter. centimeter. Hericium erinaceus is a famous and precious traditional Chinese dish, with tender meat, fragrant taste and delicious taste. It is one of the four famous dishes (hericium, bear's paw, sea cucumber, shark's fin). Hericium erinaceus is a high-protein, low-fat, high-quality food rich in minerals and vitamins. It contains unsaturated fatty acids, which can reduce blood cholesterol and triglyceride levels, regulate blood lipids, and benefit blood circulation. It is a good choice for cardiovascular patients. Ideal food; the polysaccharides, polypeptides and fatty substances it contains can inhibit the synthesis of genetic material in cancer cells, thereby preventing and treating digestive tract cancer and other malignant tumors. The moisture content of Hericium erinaceus after harvest is as high as 85% to 90%, and it is easy to rot and deteriorate. Therefore, it is mostly processed into dried mushrooms for sale. The current mainstream technology for Hericium erinaceus drying is hot air drying technology. Due to the large volume of Hericium erinaceus, it takes a long time for the whole mushroom to be dried by hot air. Especially when the surface is dried to a relatively low moisture content, a hard shell is formed, which hinders the further evaporation of internal moisture, so it is necessary to perform slow soaking and equalization for more than 12 hours. In addition, the drying speed of Hericium erinaceus is very slow because the temperature gradient of raw materials is opposite to the direction of humidity gradient during hot air drying. Due to the large size and the slow migration of water from the inside to the outside, it is not feasible to increase the drying speed by increasing the air temperature. Therefore, in the current drying process of Hericium erinaceus, only low air temperature and moderate humidity can be used to ensure product quality, and the total drying time required is usually more than 30 h.

Microwave energy penetrates deep into the material to make the inside and outside heat up at the same time to form an overall heating, and the drying time is greatly shortened. At present, many scholars use the synergistic effect of microwave and hot air to jointly dry food, usually hot air and microwave work at the same time to speed up the drying speed. For example, the drying speed of banana slices is very fast with hot air-microwave combined drying; the drying time of apple diced with hot air-microwave is reduced by more than 80% compared with that without microwave heating; Dry with hot air for 1 hour to reduce the water content to 48%, and then dry with low-power microwave for 15 minutes, which can shorten the drying time, improve efficiency, and ensure product quality; use microwave-hot air to dry fresh ginger slices to obtain sulfur-free, Aseptic high quality dried ginger products. It can be seen that the vast majority of microwave-hot air drying foods are segmented products. For large-sized foods that need to be dried as a whole, only low-temperature and slow drying plus equalization (moisture) can be used, and the drying time is extremely long. This is because the penetration depth of conventional microwave (2450MHz) is limited, especially when the moisture content of the raw material is high, the microwave energy attenuation rate is fast, which will cause the phenomenon that the internal temperature is low and the external surface is cracked due to the extremely fast heating speed. Therefore, microwave and hot air drying are usually only suitable for cutting food, such as raw materials such as flakes and blocks.

Contents of the invention

The purpose of the present invention is to solve the deficiencies of the above-mentioned technical problems, to provide a method for rapid drying of Hericium erinaceus, improve the drying rate on the premise of ensuring product quality, and reduce drying energy consumption, especially suitable for drying Hericium erinaceus processing.

The present invention is to solve the deficiencies of the above-mentioned technical problems, and the adopted technical scheme is: a kind of method for Hericium erinaceus quick drying, described method comprises the following steps:

(1) Select Hericium erinaceus: Select Hericium erinaceus with spine length ≤ 5 mm, wash and set aside;

(2) One-time hot air drying: Turn on the box-type dryer, set the air temperature to 32-36°C, ventilate and preheat for 10-20 minutes, then put the cleaned Hericium erinaceus into the box-type dryer, set the air temperature to 65 ~75°C, wind speed 2m/s, drying treatment until the moisture content is 45%, monitoring by infrared temperature measurement during the drying process, and controlling the surface temperature of Hericium erinaceus to not exceed 45°C;

(3) Low-frequency microwave treatment: put Hericium erinaceus after a hot air drying treatment into a low-frequency microwave oven, turn on the microwave after the surface temperature of Hericium erinaceus drops to room temperature, and use 915MHz low-frequency microwave for drying treatment, low-frequency microwave processing power For: 0.2W per gram of Hericium erinaceus, the infrared temperature measurement method is used to monitor the surface temperature of Hericium erinaceus during low-frequency microwave treatment, and the microwave is turned off when the surface temperature of Hericium erinaceus reaches 40°C;

(4) Secondary hot air drying: move Hericium erinaceus after low-frequency microwave treatment into a box-type dryer, set the air temperature at 65-75°C, and the wind speed at 2m/s, and dry until the moisture content is ≤7%;

(5) Pack and store the dried Hericium erinaceus.

The beneficial effects of the present invention are:

(1) The reasonable combination of hot air drying and low-frequency microwave treatment can significantly increase the drying rate of Hericium erinaceus and significantly reduce the drying energy consumption.

(2) Low-frequency microwaves have strong penetrability. Even if Hericium erinaceus is large in size, it can still heat the inside and outside at the same time. Under the condition of low power density, it can accelerate the migration of water from the inside to the outside.

(3) Low-frequency microwave treatment replaces the method of equalizing humidity in traditional hot air drying, which can save a lot of time and improve production efficiency.

(4) The tissue of Hericium erinaceus treated with low-frequency microwaves has micro-expansion, which can speed up the drying rate of hot air in the later stage and reduce the drying time.

Detailed ways

The following are specific embodiments of the present invention:

A method for rapid drying of Hericium erinaceus, the method comprises the following steps:

(1) Select Hericium erinaceus: Select Hericium erinaceus with spine length ≤ 5 mm, and wash it for later use; too long spines are prone to tip effects during microwave treatment and should be removed;

(2) One-time hot air drying: Turn on the box dryer, set the air temperature to 32°C, and preheat for 15 minutes with ventilation. The purpose of preheating is to quickly heat up Hericium erinaceus to the passivation temperature of polyphenol oxidase and reduce browning. After preheating, put the washed Hericium erinaceus into the box dryer, set the wind temperature at 70°C, and the wind speed at 2m/s, and dry it until the moisture content is 45%. Continued ventilation and drying will easily cause the surface to harden. During the drying process, the surface temperature of Hericium erinaceus is controlled not to exceed 45°C. The surface temperature of Hericium erinaceus is monitored by infrared temperature measurement. This drying section takes about 10 hours;

(3) Low-frequency microwave treatment: put Hericium erinaceus after a hot air drying treatment into a microwave oven, and turn on the microwave after the surface temperature of Hericium erinaceus drops to room temperature, otherwise the surface will absorb microwaves excessively and cause the surface water to evaporate too quickly As a result, the surface hardens, and the moisture in Hericium erinaceus cannot migrate from the inside to the outside. Use 915MHz low-frequency microwave for drying treatment, the low-frequency microwave treatment power is 0.2W/g Hericium erinaceus, turn off the microwave when the surface temperature of Hericium erinaceus reaches 40°C, and the microwave treatment time is about 2 hours;

(4) Secondary hot air drying: move the Hericium erinaceus after low-frequency microwave treatment into a box-type dryer, set the air temperature at 75°C, and the wind speed at 2m/s, and dry until the moisture content is ≤7%. The drying time is about 4 hours. Due to the micro-expansion of Hericium erinaceus tissue after low-frequency microwave treatment, the water migration speed is accelerated during the later drying process, thereby increasing the hot air drying speed;

(5) Pack and store the dried Hericium erinaceus.

The dried Hericium erinaceus product is full in shape, large in size, neat in spines, light yellow to golden in color, and has no obvious difference with traditional hot air drying products. The total drying time of traditional hot air drying methods usually takes 30 hours, while the present invention The total drying time of the rapid drying method is only about 16 hours, which significantly reduces the time used for drying and greatly improves the drying processing rate of Hericium erinaceus.

Claims (1)

1. a method for rapid drying of Hericium erinaceus, is characterized in that: described method comprises the following steps: (1) Select Hericium erinaceus: Select Hericium erinaceus with spines less than or equal to 5mm in length, wash and set aside; (2) One-time hot air drying: Turn on the box-type dryer, set the air temperature to 32-36°C, ventilate and preheat for 10-20 minutes, then put the cleaned Hericium erinaceus into the box-type dryer, set the air temperature to 65 ~75°C, wind speed 2m/s, drying treatment until the moisture content is 45%, monitoring by infrared temperature measurement during the drying process, and controlling the surface temperature of Hericium erinaceus to not exceed 45°C; (3) Low-frequency microwave treatment: Put Hericium erinaceus after a hot air drying treatment into a low-frequency microwave oven, turn on the microwave after the surface temperature of Hericium erinaceus drops to room temperature, and use 915MHz low-frequency microwave for processing. The low-frequency microwave processing power is : 0.2W per gram of Hericium erinaceus, the surface temperature of Hericium erinaceus is monitored by infrared temperature measurement during low-frequency microwave treatment, and the microwave is turned off when the surface temperature of Hericium erinaceus reaches 40°C; (4) Secondary hot air drying: move the Hericium erinaceus after low-frequency microwave treatment into a box-type dryer, set the air temperature at 65-75°C, and the wind speed at 2m/s, and dry until the moisture content is ≤7%; (5) Pack and store the dried Hericium erinaceus.