Method for fresh keeping of fresh walnuts by slow-freezing and slow-unfreezing freshelizing technology

Abstract

The invention relates to a fresh-keeping method for fresh walnuts, in particular to a method for fresh-keeping walnuts by slow freezing-slow thawing and refreshment process. The technical scheme of the invention includes peeling, grading, slow freezing, frozen storage, slow thawing and freshening. The technology of the invention extends the preservation period of fresh walnuts from 2 to 4 months to more than 10 to 12 months, and realizes the annual supply of fresh walnuts.

Description

technical field

[0001] The invention relates to a fresh-keeping method for fresh walnuts, in particular to a fresh-keeping method for fresh walnuts by slow freezing-slow thawing refreshment process. Background technique

[0002] Walnuts are favored by consumers due to their rich nutritional value and health care value. In addition, they are characterized by strong adaptability, wide cultivation, and remarkable ecological benefits. In recent years, the walnut industry has developed rapidly across the country. In 2002, the national walnut production was only 343,000 tons. By the end of 2014, the national walnut planting area reached more than 7,228,500 ha 2 , resulting in an area of ​​more than 2.856 million hm 2 , the output has reached 2.713 million tons, and the average annual growth rate of output has reached 18.81%. Both the area and output rank first in the world. However, with the decline of the overall economic development, the efficiency of the walnut industry has d...

Examples

Embodiment 1

[0018] (1) Timely harvesting: Stop irrigation and spraying 2 weeks before walnuts are harvested; choose sunny days for harvesting, and avoid high-temperature periods on sunny days when harvesting to reduce field heat carried by walnuts. Avoid rainy days, after rains and when there is dew Harvesting; the walnuts are fully matured and harvested with green skins. If the walnuts are harvested too early, the flavor is not fully formed, and after slow freezing, they are water-soaked and cannot be thawed and freshened; if they are harvested too late, the skins are dark brown and the moisture content is low. Decrease, affect the sensory commodity and taste flavor.

[0019] (2) Peel off, grading: Spray 0.5% ethephon after the walnuts with green peel are harvested, stratify and accelerate the ripening for 5 days, remove the green peel and carry out size classification;

[0020] (3) Slow freezing: put the walnuts in a fresh-keeping bag within 12 hours and place them at -2°C for slow free...

Embodiment 2

[0025] (1) Timely harvesting: Stop irrigation and spraying 2 weeks before walnuts are harvested; choose sunny days for harvesting, and avoid high-temperature periods on sunny days when harvesting to reduce field heat carried by walnuts. Avoid rainy days, after rains and when there is dew Harvesting; the walnuts are fully matured and harvested with green skins. If the walnuts are harvested too early, the flavor is not fully formed, and after slow freezing, they are water-soaked and cannot be thawed and freshened; if they are harvested too late, the skins are dark brown and the moisture content is low. Decrease, affect the sensory commodity and taste flavor.

[0026] (2) Peel off, grading: Spray 0.5% ethephon after harvesting the walnuts with green skin, stratify and accelerate ripening for 4 days, remove the green skin and carry out size classification;

[0027] (3) Slow freezing: put the walnuts in a fresh-keeping bag within 12 hours and place them at a temperature of -10°C fo...

Embodiment 3

[0033] (1) Timely harvesting: Stop irrigation and spraying 2 weeks before walnuts are harvested; choose sunny days for harvesting, and avoid high-temperature periods on sunny days when harvesting to reduce field heat carried by walnuts. Avoid rainy days, after rains and when there is dew Harvesting; the walnuts are fully matured and harvested with green skins. If the walnuts are harvested too early, the flavor is not fully formed, and after slow freezing, they are water-soaked and cannot be thawed and freshened; if they are harvested too late, the skins are dark brown and the moisture content is low. Decrease, affect the sensory commodity and taste flavor.

[0034] (2) Peel off, grading: Spray 0.4% ethephon after the walnuts with green peel are harvested, stratify and accelerate the ripening for 4 days, remove the green peel and carry out size classification;

[0035] (3) Slow freezing: put the walnuts in a fresh-keeping bag within 12 hours and place them at a temperature of -...

technical field

[0001] The invention relates to a fresh-keeping method for fresh walnuts, in particular to a fresh-keeping method for fresh walnuts by slow freezing-slow thawing refreshment process. Background technique

[0002] Walnuts are favored by consumers due to their rich nutritional value and health care value. In addition, they are characterized by strong adaptability, wide cultivation, and remarkable ecological benefits. In recent years, the walnut industry has developed rapidly across the country. In 2002, the national walnut production was only 343,000 tons. By the end of 2014, the national walnut planting area reached more than 7,228,500 ha 2 , resulting in an area of ​​more than 2.856 million hm 2 , the output has reached 2.713 million tons, and the average annual growth rate of output has reached 18.81%. Both the area and output rank first in the world. However, with the decline of the overall economic development, the efficiency of the walnut industry has d...

Examples

Embodiment 1

[0018] (1) Timely harvesting: Stop irrigation and spraying 2 weeks before walnuts are harvested; choose sunny days for harvesting, and avoid high-temperature periods on sunny days when harvesting to reduce field heat carried by walnuts. Avoid rainy days, after rains and when there is dew Harvesting; the walnuts are fully matured and harvested with green skins. If the walnuts are harvested too early, the flavor is not fully formed, and after slow freezing, they are water-soaked and cannot be thawed and freshened; if they are harvested too late, the skins are dark brown and the moisture content is low. Decrease, affect the sensory commodity and taste flavor.

[0019] (2) Peel off, grading: Spray 0.5% ethephon after the walnuts with green peel are harvested, stratify and accelerate the ripening for 5 days, remove the green peel and carry out size classification;

[0020] (3) Slow freezing: put the walnuts in a fresh-keeping bag within 12 hours and place them at -2°C for slow free...

Embodiment 2

[0025] (1) Timely harvesting: Stop irrigation and spraying 2 weeks before walnuts are harvested; choose sunny days for harvesting, and avoid high-temperature periods on sunny days when harvesting to reduce field heat carried by walnuts. Avoid rainy days, after rains and when there is dew Harvesting; the walnuts are fully matured and harvested with green skins. If the walnuts are harvested too early, the flavor is not fully formed, and after slow freezing, they are water-soaked and cannot be thawed and freshened; if they are harvested too late, the skins are dark brown and the moisture content is low. Decrease, affect the sensory commodity and taste flavor.

[0026] (2) Peel off, grading: Spray 0.5% ethephon after harvesting the walnuts with green skin, stratify and accelerate ripening for 4 days, remove the green skin and carry out size classification;

[0027] (3) Slow freezing: put the walnuts in a fresh-keeping bag within 12 hours and place them at a temperature of -10°C fo...

Embodiment 3

[0033] (1) Timely harvesting: Stop irrigation and spraying 2 weeks before walnuts are harvested; choose sunny days for harvesting, and avoid high-temperature periods on sunny days when harvesting to reduce field heat carried by walnuts. Avoid rainy days, after rains and when there is dew Harvesting; the walnuts are fully matured and harvested with green skins. If the walnuts are harvested too early, the flavor is not fully formed, and after slow freezing, they are water-soaked and cannot be thawed and freshened; if they are harvested too late, the skins are dark brown and the moisture content is low. Decrease, affect the sensory commodity and taste flavor.

[0034] (2) Peel off, grading: Spray 0.4% ethephon after the walnuts with green peel are harvested, stratify and accelerate the ripening for 4 days, remove the green peel and carry out size classification;

[0035] (3) Slow freezing: put the walnuts in a fresh-keeping bag within 12 hours and place them at a temperature of -...