CN102461659A - Processing method of green sword beans - Google Patents

Abstract

The invention discloses a quick-freezing and drying method of green sword beans, comprising the following steps of: selecting, removing ends and veins, washing, blanching, precooling, detearing, individually quick freezing, packaging and storing. The freshness of the produced green sword beans is maintained to the maximum. In addition, original color, flavor and nutritional components of the green sword beans are also maintained.

Description

The processing method of French bean

Technical field

The invention belongs to the vegetables manufacture field, relate in particular to the processing method of French bean.

Background technology

Quick-frozen fresh vegetables are to produce comparatively common processing technology at present, and China's batch production is produced also has nearly 30 years history.But there are very big-difference in different pretreating process, the control of quick-frozen condition to the research of quality of vegetable influence, because control and quality control criterion disunity have caused different batches, difference to produce the widely different of product quality in season thus.The French bean color and luster is dark green, and is delicious fragrant and sweet, organize tender and crisp, the no fiber sense of food, nutritious, receive liking of various countries people.But fresh French bean storage at normal temperature and long-distance transport can cause quality to descend, thus its part as raw vegetable sell nearby edible outside, remainder is used for the improvement trade for export French bean.One of main four big kinds that frozen fresh stringless green bean exports as China's quick-frozen legume vegetable, export volume increases year by year.But China's research aspect the French bean freeze-dry process at present lags behind.The vacuum freeze-drying dry technology is the drying and dehydrating technology that Refrigeration Technique and vacuum technique combine; Freeze-dried vegetable is that fresh vegetables is freezed earlier; Distillation is dewatered and the drying vegetables of acquisition under vacuum condition again, and shape, look, flavor, nutritional labeling are all identical basically with the aquatic foods article, and rehydration is good.

Summary of the invention

Technical problem to be solved by this invention is, a kind of accelerated freeze-drying method of French bean is provided, and can not only keep the original freshness of French bean to greatest extent and keep the color and luster local flavor and the nutrition of original French bean.

The accelerated freeze-drying method of French bean comprises the steps:

1, chooses → go end and go muscle → cleaning

Through selection, rejecting has the raw material of wind spot, scar, deformity, machinery wound, disease and pest; Go end to remove muscle: French bean is obstructed the base of a fruit and the beans point is plucked, tears the muscle of both sides, can not be excessive when plucking in order to avoid disconnected bar, can not be with the scissors haircut of band rust in order to avoid cause the rust head; Clean:, clean silt, dust, worm and worm's ovum, agricultural chemicals, chemical fertilizer, microorganism and impurity etc. with clear water immediately attached to the surface to through the bright beans after the above-mentioned processing.

2, blanching

In the blanching pond, puts about eighty per cant water into before the blanching, uses steam heated then, treat that water boils after, the raw material that is contained in plastic basket or the bamboo basket is immersed in the boiling water in the lump, the mass ratio of water and raw material is 10: 1.French bean carries out blanching 1.0～2.0min for 96～98 ℃ in temperature; To notice that in the blanching process raw material need stir up and down, with well-done, the no raw taste of chewing, the water in the blanching pond will often be changed, and to keep hygienically clean, the blanching water should keep alkalescent, and p H value should be controlled in 7.0～7.5.Otherwise the chlorophyll under acid condition in the bright beanpod can be destroyed, and becomes pheophytin, freezing, losing green gradually in the cold storage procedure and become yellow crineous, thus the commodity value of losing.

3, precooling → draining

Adopt the frozen water cooling of health, its temperature is 5～15 ℃, and the control of cooled French bean draining is done.

4, individual quick freezing

Adopt two-period form fluidization individual quick freezing technology

Material bed thickness is about 40mm, and the material initial temperature is subzero 5 ℃, and the cold air temperature is subzero 20～30 ℃, and the cold air flow velocity of first freezing zone is 5---6m/s, and the cold air flow velocity of second freezing zone is 4---5m/s, and the quick-frozen time is 5min.Adopt this quick-freeze craft, make beans English in quick-frozen, present fluidization, realize individual quick freezing, it is subzero below 20 ℃ to let the geometric center temperature of French bean comparatively fast drop to, and beans English monomer adhesion.

5, lyophilization

Reduce the physical property that its boiling point also reduces according to water with pressure, place vacuum tank to vacuumize precooling food, when pressure reaches certain numerical value, the moisture start vaporizer of food surface.Under vacuum condition, realize the distillation dehydration, the French bean moisture content is below 3% after the lyophilization, and energy consumption level reaches the advanced level of whenever taking off 1kg ice power consumption 0.55kw.h.

6, packing

Must in low temperature (5 ℃) packing shop, pack after the freeze-drying, weigh, and, seal then, case through the metal detector inspection.

7, storage

The relative humidity of freezer is controlled between 95%～100%, and amplitude of fluctuation is in 5%

The freeze-drying French bean of producing through above-mentioned steps owing in the blanching process, destroy the activity of enzyme in the bright beans, prevents to have kept the nutritional labeling of bright beans freezing, producing yellow in the cold storage procedure and peculiar smell occurs; Kill microorganism, the worm's ovum on raw material surface; Reduce the agricultural chemicals vestiges; Remove the inner air of de-cellular system and the cement material of moisture and epidermis, make the product tissue soft, volume-diminished is beneficial to the packing of product, improves quality of finished; Removed raw taste.Again because in the quick-frozen process; Adopt the individual quick freezing method; Prevent that effectively beanpod from causing the big ice crystal of iuntercellular moisture generation to cause explosion owing to freezing slowly; The loss of the back cell juice that thaws be can reduce simultaneously, original color, nutritional labeling and favorable tissue form thereof kept through lyophilization.

The specific embodiment

1, chooses → go end and go muscle → cleaning

Through selection, rejecting has the raw material of wind spot, scar, deformity, machinery wound, disease and pest; Go end to remove muscle: French bean is obstructed the base of a fruit and the beans point is plucked, tears the muscle of both sides, can not be excessive when plucking in order to avoid disconnected bar, can not be with the scissors haircut of band rust in order to avoid cause the rust head; Clean:, clean silt, dust, worm and worm's ovum, agricultural chemicals, chemical fertilizer, microorganism and impurity etc. with clear water immediately attached to the surface to through the bright beans after the above-mentioned processing.

2, blanching

In the blanching pond, puts about eighty per cant water into before the blanching, uses steam heated then, treat that water boils after, the raw material that is contained in plastic basket or the bamboo basket is immersed in the boiling water in the lump, the mass ratio of water and raw material is 10: 1.French bean carries out blanching 1.0min for 96 ℃ in temperature; To notice that in the blanching process raw material need stir up and down, with well-done, the no raw taste of chewing, the water in the blanching pond will often be changed, and to keep hygienically clean, the blanching water should keep alkalescent, and p H value should be controlled at 7.0.Otherwise the chlorophyll under acid condition in the bright beanpod can be destroyed, and becomes pheophytin, freezing, losing green gradually in the cold storage procedure and become yellow crineous, thus the commodity value of losing.

3, precooling → draining

Adopt the frozen water cooling of health, its temperature is 5 ℃, and the control of cooled French bean draining is done.

4, individual quick freezing

Adopt two-period form fluidization individual quick freezing technology

Material bed thickness is about 40mm, and the material initial temperature is 5 ℃, and the cold air temperature is subzero 25 ℃, and the cold air flow velocity of first freezing zone is 5m/s, and the cold air flow velocity of second freezing zone is 4m/s, and the quick-frozen time is 5min.Adopt this quick-freeze craft, make beans English in quick-frozen, present fluidization, realize individual quick freezing, it is subzero below 20 ℃ to let the geometric center temperature of French bean comparatively fast drop to, and beans English monomer adhesion.

5, lyophilization

Under vacuum condition, realize the distillation dehydration, moisture content is below 3% after the lyophilization

6, packing

Must in low temperature (5 ℃) packing shop, pack after the quick-frozen, weigh, and, seal then, case through the metal detector inspection.

7, storage

The relative humidity of freezer is controlled at 95%, and amplitude of fluctuation is in 5%.

Claims (1)

1. the accelerated freeze-drying method of French bean is characterized in that this method comprises the steps:

(1), chooses → go end and go muscle → cleaning

Through selection, rejecting has the raw material of wind spot, scar, deformity, machinery wound, disease and pest; Go end to remove muscle: French bean is obstructed the base of a fruit and the beans point is plucked, tears the muscle of both sides, can not be excessive when plucking in order to avoid disconnected bar, can not be with the scissors haircut of band rust in order to avoid cause the rust head; Clean:, clean silt, dust, worm and worm's ovum, agricultural chemicals, chemical fertilizer, microorganism and impurity etc. with clear water immediately attached to the surface to through the bright beans after the above-mentioned processing.

(2), blanching

In the blanching pond, puts about eighty per cant water into before the blanching, uses steam heated then, treat that water boils after, the raw material that is contained in plastic basket or the bamboo basket is immersed in the boiling water in the lump, the mass ratio of water and raw material is 10: 1.French bean carries out blanching 1.0min for 96 ℃ in temperature; To notice that in the blanching process raw material need stir up and down, with well-done, the no raw taste of chewing, the water in the blanching pond will often be changed, and to keep hygienically clean, the blanching water should keep alkalescent, and p H value should be controlled at 7.0.Otherwise the chlorophyll under acid condition in the bright beanpod can be destroyed, and becomes pheophytin, freezing, losing green gradually in the cold storage procedure and become yellow crineous, thus the commodity value of losing.

(3), precooling → draining

Adopt the frozen water cooling of health, its temperature is 5 ℃, and the control of cooled French bean draining is done.

(4), individual quick freezing

Adopt two-period form fluidization individual quick freezing technology

Material bed thickness is about 40mm, and the material initial temperature is 5 ℃, and the cold air temperature is subzero 25 ℃, and the cold air flow velocity of first freezing zone is 5m/s, and the cold air flow velocity of second freezing zone is 4m/s, and the quick-frozen time is 5min.Adopt this quick-freeze craft, make beans English in quick-frozen, present fluidization, realize individual quick freezing, let the geometric center temperature of French bean comparatively fast drop to below one 18 ℃, and beans English monomer adhesion.

(5), lyophilization

Under vacuum condition, realize the distillation dehydration, moisture content is below 3% after the lyophilization

(6), packing

Must in low temperature (5 ℃) packing shop, pack after the quick-frozen, weigh, and, seal then, case through the metal detector inspection.

(7), storage

The relative humidity of freezer is controlled at 95%, and amplitude of fluctuation is in 5%.