Color-protecting processing method of freeze drying onion

A processing method and drying technology, applied in the field of color protection processing of natural green color, can solve problems such as excessive sulfite and metal ion residues, and achieve the effects of accelerating dehydration rate, ensuring safety, and inhibiting oxidation.

CN102640916AActive Publication Date: 2012-08-22福建省新闽商业运营管理有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2012-08-22

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Abstract

The invention discloses a color-protecting processing method of freeze drying onion, wherein the method comprises the following steps of: immersing onion materials in an alkaline water solution firstly; then bleaching slightly in an alkaline warm water, cleaning, soaking by using a natural reducing sugar solution and draining; then freezing the onion materials by adopting a slow freezing mode; finally, freezing, drying, dehydrating and processing the frozen onion materials, wherein the slow freezing mode is that the total freezing time is not less than 5 hours, and the central temperature of the onion materials after freezing is less than and equal to minus 22 DEG C. After the scheme is adopted, according to the invention, the acid degree is regulated through the alkaline water solution firstly, and chlorophyll is prevented from being subjected to de-magging to lead to the defect of green fading of the materials, thus the green of the onion materials is kept to be stable, and the problem that the metal content of the materials in the prior art exceeds the standard is overcome. Moreover, according to the invention, a non-toxic natural reducing sugar solution is utilized as a processing auxiliary material for protecting the color, the problem that the sulfite residual quantity of the product after color-protection of the freeze drying onion exceeds the standard is overcome, and the product safety is ensured.
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Description

technical field

[0001] The invention relates to a processing method for freeze-drying shallots, in particular to a color-protecting processing method capable of protecting the natural green color of shallots. Background technique

[0002] Onion belongs to Liliaceae Allium, a perennial herb. Onions can be divided into chives (also known as chives) and medium-tube onions. The plants are clustered and upright, the leaves are thin tubes, the height of the plant is 35-55 cm, and the leaves are grass green.

[0003] Freeze-dried green onion products are high-grade dehydrated seasoning vegetables that are very popular in the international market. The price of the product is closely related to the sensory indicators such as color, fragrance, and hygienic indicators such as microorganisms and pesticide residues. The dehydration processing of vegetables usually requires color protection treatment of materials. Generally, high temperature heating and blanching treatment is used to pro...

Examples

Embodiment 1

[0035] Example 1: All green onions

[0036] The color-protecting processing method of freeze-dried shallots of the present invention is realized through the following steps:

[0037] (1) The all-green medium-tube green onions picked in the controlled vegetable base are transported to the processing plant in about 4 hours, and are required to be put into pre-processing within 24 hours. The medium-tube shallots that are not processed in time after entering the factory are first put into the refrigerator (0~ 5°C). During processing, cut off the part with the white head of the root of the medium-tube spring onion, select and remove soft rot, rotten deterioration, disease spots, burnt tail and other impurities and foreign objects, and then wash it again.

[0038] (2) Prepare 0.06~0.12wt% edible soda ash (soda) aqueous solution, control the pH to 9.0~11.0, neatly put the middle tube scallions treated in step (1) into the edible soda ash aqueous solution for 5~8 minutes, Then wash ...

Embodiment 2

[0045] Example 2: German shallots

[0046] The color-protecting processing method of freeze-dried shallots of the present invention is realized through the following steps:

[0047] (1) German shallots picked at the vegetable raw material base are transported to the processing plant in about 8 hours, and processing is required to start within 48 hours. Before processing, German shallots should be placed in a refrigerator (0-5°C). During processing, German onion raw materials are selected to remove soft rot, rotten deterioration, disease spots, burnt tails, impurities and foreign objects, and then washed once.

[0048] (2) Prepare 0.08~0.15%wt% edible soda ash (soda) aqueous solution, control pH 9.0~11.0, neatly put the German green onions treated in step (1) into the edible soda ash aqueous solution for 7~8 minutes, Then wash with running water 3 times. The edible soda ash aqueous solution is renewed after being used 4 to 5 times.

[0049] (3) Take clean tap water, heat the...