Method for preparing a freeze-drying crisp fruit and vegetable piece

Abstract

The invention discloses a method for preparing a freeze-drying crisp fruit and vegetable piece, which includes the following steps: blanching raw materials for killing enzyme; preparing a color protection liquid using citric acid concentration, sodium isoascorbate concentration, or cysteine hydrochloride concentration, sodium phytate concentration and embedding medium, wherein, the ratio between the color protection liquid and the slice liquid material is 0.25-1:1; slowly freezing fruit paste with 4-7 mm thickness below a eutectic point at minus 30 DEG C. for one hour; placing the fruit paste on a separator plate of a vacuum lyophilizer after the machine is precooled to a cold trap minus 50 DEG C. with 30 Pa vacuum degree and 40 DEG C. separator plate temperature; heating and drying by programs, wherein, 3-5 DEG C. rises every hour when the temperature is below 10 DEG C.; keeping temperature at 10 DEG C. for 1 hour; heating continuously for rising 5-7 DEG C. every hour; keeping temperature for 2 hours at 40 DEG C.; obtaining the crisp fruit and vegetable pieces with water content below 7% after refrigeration; slicing and packing products in an independent drying room with air humidity 40-50%. The invention has a distinct fruit and vegetable original flavour with larger market prospect.

Description

technical field [0001] The invention belongs to the technical field of agricultural product processing, and in particular relates to a method for preparing crisp fruit and vegetable slices by vacuum freeze-drying technology. Background technique [0002] Fruits and vegetables are the main food sources for people to obtain vitamins and minerals daily. They play an important role in improving the acidic environment of the human body and regulating the physiological metabolism of the human body. They are one of the sources of leisure food that people love. At present, the popular fruit and vegetable snack foods in the market mainly include preserved fruit, fruit and vegetable chips, preserved plums, potato chips, etc., with different production processes and different taste styles. Most fruit and vegetable snack foods are packaged in the form of dry products, and the drying technology mostly adopts low-temperature blast drying, drum drying, and vegetable frying. During the dry...

AI Technical Summary

Problems solved by technology

Most fruit and vegetable snack foods are packaged in the form of dry products, and the drying technology mostly adopts low-temperature blast drying, drum drying, and vegetable frying. During the drying process, the temperature is too high, the loss of nutrients is too much and the original flavor of fruits and vegetables is lost, and due to the use of frying and seasoning and the use of a large number of food additives, the oil is also easy to deteriorate during storage, which is consistent with the people's pursuit of natural health. Contradict

Later, people applied vacuum freeze-drying technology to fruit and vegetable snack foods. According to statistics, most of the previous researches were focused on freeze-dried fruit and vegetable crisps and freeze-dried fruit and vegetable powder. So far, no patents for freeze-dried fruit and vegetable crisps have been found. Most of the fruit and vegetable freeze-dried chips on the market are directly sliced ​​and then freeze-dried. Although the product maintains the color and fragrance of the raw materials, for tropical fruits with high sugar content, the chips are slow to rehydrate after entering the mouth and are easy to stick to the teeth. affect the taste and consumption experience of the product

For example, Patent No. 201210232056.0 mentions the use of vacuum freeze-drying technology to produce instant fruit and vegetable powder, which has a novel formula and natural nutrition, but it needs to be rehydrated when eating, and does not have the convenience and practicality of leisure food.

Patent No. 200710133377.4 refers to the method of preparing fruit and vegetable chips by vacuum freeze-drying and then dipping treatment. The processing method is novel, the process is complicated, and the production cost is high

Patent No. 201010282097.1 mentions vacuum freeze-drying to prepare diced mangoes. The method is novel, but the process of blanching and color protection inevitably loses water-soluble and heat-sensitive nutrients.