阅读说明：本技术 一种糯玉米的微低温长效保鲜方法 (Micro-low temperature long-acting preservation method for waxy corn ) 是由 牛豫华 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种糯玉米的微低温长效保鲜方法,属于农产品保鲜技术领域。所述保鲜方法包括采收、循环预冷及分级微低温保鲜工序,糯玉米在鲜穗水分含量60-75%时采收,去除污染部分。然后进行强制循环预冷,使玉米芯在5-10min内预冷至5-7℃,保持30-60min后将糯玉米先在1-4℃微冷24-48h,再在-2-0℃微冻保存即可。所述保鲜方法能够诱导糯玉米籽粒的自然休眠,有效降低玉米的呼吸代谢速率和失水量,钝化酶活性,玉米籽粒中可溶性糖的损失更少,还原糖的保留率更高,延缓了玉米籽粒的衰老,极大地保持了糯玉米的营养成分和感官品质。所述保鲜方法无添加剂,保鲜时效长,工艺流程少,设备通用率高,处理速度快,操作简便,容易控制,推广应用价值高。(The invention discloses a micro-low temperature long-acting preservation method for waxy corn, and belongs to the technical field of agricultural product preservation. The fresh-keeping method comprises the working procedures of harvesting, circulating precooling and grading low-temperature fresh-keeping, wherein the waxy corns are harvested when the moisture content of the fresh ears is 60-75%, and the polluted parts are removed. And then performing forced circulation precooling to ensure that the corn cob is precooled to 5-7 ℃ within 5-10min, keeping the temperature for 30-60min, then carrying out slight cooling on the waxy corn for 24-48h at 1-4 ℃, and then carrying out slight freezing storage at-2-0 ℃. The preservation method can induce the natural dormancy of the waxy corn grains, effectively reduce the respiratory metabolism rate and water loss of the corn, passivate the enzyme activity, reduce the loss of soluble sugar in the corn grains, improve the retention rate of reducing sugar, delay the aging of the corn grains and greatly maintain the nutritional ingredients and sensory quality of the waxy corn. The fresh-keeping method has the advantages of no additive, long fresh-keeping time, few process flows, high equipment utilization rate, high treatment speed, simplicity and convenience in operation, easiness in control and high popularization and application values.)

1. A micro-low temperature long-acting preservation method of waxy corn is characterized by comprising the working procedures of harvesting, circulating precooling and grading micro-low temperature preservation, and specifically comprises the following steps:

A. harvesting: harvesting waxy corns when the moisture content of the fresh ears is 60-75%, and removing the polluted parts;

B. and (3) circulating precooling: forcibly circulating and precooling the harvested waxy corns to ensure that the corn cobs are precooled to 5-7 ℃ within 5-10min and kept for 30-60 min;

C. grading and slightly low-temperature preservation: the pre-cooled waxy corn is firstly subjected to slight cooling at 1-4 ℃ for 24-48h, and then is subjected to slight freezing storage at-2-0 ℃.

2. The low-temperature long-acting preservation method as claimed in claim 1, wherein in the harvesting procedure, the waxy corns are harvested when the moisture content of the fresh ears is 65-70%.

3. A micro-low temperature long-acting fresh-keeping method according to claim 1, wherein in the circulating precooling process, the precooling adopts any one of forced circulation air cooling or water cooling.

4. The method according to claim 1, wherein in the step of circulating pre-cooling, the retention time of pre-cooling is 45 min.

5. The method as claimed in claim 1, wherein the waxy corn is coated with polyvinyl chloride film in the step of graded low temperature preservation.

6. A micro-low temperature long-acting fresh-keeping method according to claim 5, characterized in that in the step of graded micro-low temperature fresh-keeping, the thickness of the polyvinyl chloride film is 0.5-0.6 μm, and 1-3 holes with 5-6mm are reserved.

7. A micro-low temperature long-acting fresh-keeping method according to any one of claims 1, 5 or 6, characterized in that in the step of graded micro-low temperature fresh-keeping, the micro-cooling temperature is 2-3 ℃ and the micro-cooling time is 36 h.

8. A micro-low temperature long-acting fresh-keeping method according to any one of claims 1, 5 or 6, wherein in the grading micro-low temperature fresh-keeping procedure, the micro-freezing temperature is-1 ± 0.5 ℃.

9. A micro-low temperature long-acting fresh-keeping method according to any one of claims 1, 3 or 4, characterized in that in the grading micro-low temperature fresh-keeping procedure, the fresh-keeping time of the waxy corn in the micro-frozen state can reach 20-40 days.

Technical Field

The invention belongs to the technical field of agricultural product preservation, and particularly relates to a micro-low temperature long-acting preservation method for waxy corn.

Background

Waxy corn mainly originates from Guangxi and Yunnan areas in China, and is a natural variation type of common corn in the cultivation process. The waxy corn grains have extremely high amylopectin content, are rich in various vitamins, have soft mouthfeel and have waxy and fragrant taste, so the waxy corn grains are popular with consumers. However, the taste quality and the nutritional value of the waxy corn are influenced by various factors such as respiration, enzymolysis mode and the like, so that the preservation treatment after picking becomes a key link in the production and circulation of the waxy corn. In order to keep the fresh, sweet and glutinous taste of the waxy corn, the traditional processing method needs to strictly control the picking initial time and the storage time, has large limitation and is inconvenient for large-scale production. Based on the method, the invention aims to provide the waxy corn low-temperature long-acting preservation method which is simple and convenient to operate, short in process flow, strong in equipment universality and free of additives, and the taste quality and the nutritional value of the fresh waxy corn are reserved to the maximum extent.

Disclosure of Invention

The invention aims to provide a slight low-temperature long-acting preservation method for waxy corns.

The purpose of the invention is realized as follows: the micro-low temperature long-acting preservation method of the waxy corn comprises the working procedures of harvesting, circulating precooling and grading micro-low temperature preservation, and specifically comprises the following steps:

A. harvesting: harvesting waxy corn when the moisture content of the fresh ear is 60-75%, and removing the polluted part.

B. And (3) circulating precooling: and (3) forcibly circulating and precooling the harvested waxy corns, precooling the corn cobs to 5-7 ℃ within 5-10min, and keeping the temperature for 30-60 min.

C. Grading and slightly low-temperature preservation: the pre-cooled waxy corn is firstly subjected to slight cooling at 1-4 ℃ for 24-48h, and then is subjected to slight freezing storage at-2-0 ℃.

In the harvesting procedure, the waxy corns are harvested when the moisture content of the fresh ears is 65-70%.

In the circulating precooling procedure, the precooling adopts any one of forced circulating air cooling or water cooling modes. The pre-cooling hold time was 45 min.

In the grading micro-low temperature preservation process, the waxy corns are coated with a polyvinyl chloride film. The thickness of the polyvinyl chloride film is 0.5-0.6 μm, and 1-3 holes of 5-6mm are reserved at two ends of the corn cob when the corn is coated.

In the grading micro-low temperature fresh-keeping working procedure, the micro-cooling temperature is 2-3 ℃, the micro-cooling time is 36 hours, and the micro-freezing temperature is-1 +/-0.5 ℃. The preservation time of the waxy corn in the slightly frozen state can reach 20 to 40 days.

The invention has the beneficial effects that: in the grading micro-low temperature treatment, the selection of micro-freezing temperature, micro-freezing temperature and retention time can effectively reduce the respiratory metabolism rate and water loss of the waxy corn and passivate the activity of soluble starch synthetase and starch branching enzyme. The loss of soluble sugar in the waxy corn grains is less, the retention rate of reducing sugar is higher, and the starch content changes slowly, so that the nutritional ingredients and the sensory quality of the waxy corn are greatly retained. Secondly, the adopted precooling, slightly cooling and slightly freezing gradual low-temperature domestication process can fully reduce the accumulation amount of malondialdehyde in the corn kernels, better maintain the activities of ascorbic acid peroxidase, superoxide dismutase and catalase, delay the aging of the corn kernels during long-term preservation and further enhance the sensory quality of the waxy corn. The grading micro-low temperature preservation method can induce the natural dormancy of the corn grains, has no additive, long preservation time, less process flow, high equipment utilization rate, high treatment speed, simple and convenient operation, easy control, no loss of nutrient components of the waxy corn and no reduction of color, aroma and taste, and high popularization and application value.

Detailed Description

The present invention is further illustrated but not limited in any way by the following description, and any alterations or substitutions based on the teachings of the present invention are intended to fall within the scope of the present invention.

Example 1

Harvesting waxy corn when the moisture content of the fresh ear is 65-70%, wherein the harvesting time is preferably in the early morning, and removing the polluted parts of bract, filament and ear stalk. Forced circulation air cooling is carried out on the corn cobs, so that the corn cobs are precooled to 5-7 ℃ within 8min and kept for 35 min. Then, the corn cobs were coated with a polyvinyl chloride film having a thickness of 0.5 μm while leaving 2 holes of 5 to 6mm at both ends of the corn cobs. Then, the corn cobs are firstly cooled for 36 hours at the temperature of 2 ℃ and then are frozen and stored at the temperature of-1.5 ℃. The fresh-keeping time of the waxy corn in a slightly frozen state can reach 20-40 days.

Example 2

Harvesting waxy corn when the moisture content of the fresh ear is 60-70%, wherein the harvesting time is preferably in the early morning, and removing the polluted parts of bract, filament and ear stalk. Forced circulation air cooling is carried out on the corn cobs, so that the corn cobs are precooled to 5-7 ℃ within 7min and kept for 45 min. Then, the corn cobs were coated with a polyvinyl chloride film having a thickness of 0.6 μm, leaving 3 holes of 5-6mm at both ends of the corn cobs. Then, the corn cob is firstly cooled for 48 hours at 3 ℃ and then is frozen and preserved at 0.5 ℃. The fresh-keeping time of the waxy corn in a slightly frozen state can reach 20-40 days.

Example 3

Harvesting waxy corn when the moisture content of the fresh ear is 65-75%, wherein the harvesting time is preferably in the early morning, and removing the polluted parts of bract, filament and ear stalk. Forced circulation air cooling is carried out on the corn cobs, so that the corn cobs are precooled to 5-7 ℃ within 5min and are kept for 60 min. Then the corn cob is coated with polyvinyl chloride film with thickness of 0.5 μm, and 1 hole with thickness of 5-6mm is reserved at two ends of the corn cob. Then, the corn cob is firstly cooled for 24 hours at 1 ℃ and then is frozen and stored at-2 ℃. The fresh-keeping time of the waxy corn in a slightly frozen state can reach 20-40 days.

Example 4

Harvesting waxy corn when the moisture content of the fresh ear is 65-70%, wherein the harvesting time is preferably in the early morning, and removing the polluted parts of bract, filament and ear stalk. Forced circulation air cooling is carried out on the corn cobs, so that the corn cobs are precooled to 5-7 ℃ within 10min and kept for 30 min. Then, the corn cobs were coated with a polyvinyl chloride film having a thickness of 0.6 μm while leaving 2 holes of 5-6mm at both ends of the corn cobs. Then, the corn cobs are firstly cooled for 36 hours at 4 ℃ and then are frozen and stored at 0 ℃. The fresh-keeping time of the waxy corn in a slightly frozen state can reach 20-40 days.