CN100502685C - A method for preventing brown stain in process of fruit and vegetable pulping by low temperature deoxygenation of liquid nitrogen - Google Patents

Abstract

The present invention discloses liquid nitrogen low temperature fruit and vegetable pulping process without browning and belongs to the field of food processing technology. The technological scheme includes the following steps: sorting fruit or vegetable, washing, microwave deactivation of enzyme, peeling, pre-cooling, crushing, pulping while spraying liquid nitrogen, blending, homogenizing, sterilizing to obtain fruit or vegetable paste product or semi-product, and abacterial packing or further processing. Spraying liquid nitrogen for low temperature no-oxygen pulping can reduce browning of fruit and vegetable, especially tropical and subtropical fruit and vegetable, obviously, and raise quality and taste of fruit and vegetable products.

Description

A kind of method of utilizing the liquid nitrogen cryogenics deoxygenation to prevent the fruit and vegetable pulping brown stain

Technical field

The present invention relates to a kind of food fresh-keeping method, specifically is a kind of method of utilizing the liquid nitrogen cryogenics deoxygenation to prevent the fruit and vegetable pulping brown stain, belongs to food processing field.

Background technology

China is one of fruits and vegetables the biggest in the world producing country, and along with the adjustment of China's agricultural structure, fruits and vegetables are produced fast-developing.But still to eat raw, average storage and working modulus are less than 15% at present.China's storage fruit and vegetable and process technology have obtained significant progress in recent years, particularly converted products such as Juice, sauce, powder come into the market, solved the difficult problem of seasonal sale, reduced and adopted back loss and storing loss, enriched the kind of garden stuff processing product, realized rising in value and increasing farmers' income, become China's fruits and vegetables and already develop main outlet.But most of fruits and vegetables very easily produce brown stain, and process control is bad, will cause the bad change of product color, and quality and taste all are difficult to win consumers in general's edible desire, and what have can not accept substantially.A difficult problem of at first running in storage fruit and vegetable and the processing is exactly the change of fruits and vegetables color, and promptly so-called brown stain, brown stain are the stubborn problems the most that takes place in fruit and vegetable food processing and the storage, and it reduces product color variation, back muddiness, nutritive value.The reason that produces brown stain is very complicated, but main cause has three kinds: the one, and enzymatic browning; The 2nd, non-enzymatic browning is as Maillard reaction, oxidation reaction etc.; The 3rd, the change of contained pigment own.For a long time, brown stain mechanism and prevent that brown stain from being the basic problem of fruit vegetables storing processing, therefore resolve the brown stain in the fruits and vegetables pulverizing pulping process, make fruits and vegetables keep original color and taste, fresh natural, the abundant nutrition composition that keeps fruit juice, pulp, having become the key of whole process, also is " bottleneck " of present fruit and vegetable processing industry.Common solution mainly adopts the enzyme that goes out that heats up, as high temperature, high pressure etc.; Next is to adopt low temperature to reduce the activity of polyphenol oxidase, and oxygen barrier or add antioxidant etc. and reduce oxidation in food by every possible means also has in addition by methods such as adsorbing metal ions simultaneously.Above method is the technology relative complex not only, the cost height, and the while has also been destroyed the part nutritional labeling of fruits and vegetables, and effect is not ideal enough.And data shows, 80% brown stain results from pulping process, has become the century difficult problem in food storage processing basin so prevent the fruit and vegetable pulping brown stain.

Summary of the invention

The object of the present invention is to provide a kind of method that produces brown stain when utilizing the liquid nitrogen cryogenics deoxygenation to prevent fruit and vegetable pulping.

Main component in the earth atmosphere is nitrogen and oxygen, and nitrogen belongs to the asphyxiating inert gas, colourless, tasteless, odorless, and chemical property is " odd jobs ", chemical reaction does not take place with any material down in state usually.Utilize the liquid nitrogen vaporization volume to expand suddenly and can discharge oxygen in the beater, reduce oxygen concentration rapidly, slow down oxidation; Secondly the liquid temperature of nitrogen is very low, is-196 ℃ transparency liquid under atmospheric pressure state, and the more heat of portability has stronger refrigerating capacity during vaporization.Suffocating and inhibitory action because asphyxiating inert nature, nitrogen have bacterium and other microorganisms, add that the solubility of nitrogen in water, grease is very little, is the fresh-keeping gas of food antiseptic of function admirable.Filling nitrogen making beating utilizes these characteristic oxygen barrier deoxygenations just, reduces active and other chemical reaction rates that temperature reduces polyphenol oxidase in the enzymatic browning simultaneously.The present invention utilizes the special nature of liquid nitrogen and the special procedure of making beating to carry out.

Technical scheme of the present invention is:

Select the blunt enzyme of fruits and vegetables → cleaning → microwave → peeling → precooling → chopping → spray nitrogen making beating → allotment → homogeneous → sterilization → fruit and vegetable jam product or semi-finished product → aseptic packaging or following process.

The present invention utilizes the intrinsic characteristic of liquid nitrogen, quantitatively sprays liquid nitrogen in pulverizing pulping process, and the realization fruits and vegetables are pulverized making beating under the environment of low temperature anaerobic, can protect the natural colored of fruit, vegetable juice series products, improve quality and taste.Fruit-vegetable fibre presents fragility at low temperatures simultaneously, can reduce the energy consumption in the pulping process, and improve pulping rate and crushing juice rate, to the production technology level of Juice, fruit and vegetable jam, spray dried powder series products and the raising of product quality, basis and huge impetus are arranged.

The specific embodiment

Concrete operations of the present invention can be carried out according to the following steps:

A. select fruits and vegetables

A.1 adopt hand picking to reject decayed fruit, also can

A.2 utilize the workbench that flows to carry out,

B. clean

B.1 select drinking water

B.2 utilize the spray mode to carry out,

C. the blunt enzyme of microwave

C.1 the process conditions of the blunt enzyme of microwave can be set according to the enzymatic activity and the plant capacity of different material

C.2 60-80s between optional time

C.3 power 700-800W

C.4 quick polyphenol oxidase (PPO) and the peroxidase (POD) in the passivation fruits and vegetables under the double effect of microwave magnetic field and heat, the nutrient of maintenance thermal sensitivity class, as vitamin C, aldehydes matter etc.,

D. peeling

D.1 select peeling according to different material and converted products, as banana, oranges and tangerines, pineapple etc.

D.2 also can select not remove the peel, as processing apple, strawberry etc.,

E. precooling

The useless nitrogen that e.1 can utilize beater to discharge carries out,

F. chopping

F.1 in case of necessity fruits and vegetables (as pineapple) are shredded,

G. spray the nitrogen making beating

G.1 according to the biology and the processing characteristics of different fruits and vegetables, control the liquid nitrogen spray amount

G.2 measure the temperature and the dissolved oxygen of slurry automatically

G.3 utilize temperature control to realize decide dropping liquid nitrogen and pull an oar, realizing best deoxygenation and cooling,

H. allotment

H.1 add various components according to prescription,

I. homogeneous,

J. sterilization

J.1 cold sterilization in can adopting,

K. make fruit and vegetable jam product or semi-finished product,

L. aseptic packaging or enter next procedure.

Fruit and vegetable jam and Juice are one of major products of garden stuff processing, also be that market is more welcome, the big product of material quantity is handled in processing, and beating process is the indispensable operation of this series products, utilize low temperature deoxygenation making beating technology, make fruits and vegetables especially the browning degree of fruits and vegetables in pulping process of tropical and subtropical zone can reduce more than 60% than prior art, the basic natural colour that keeps raw material, nakedly look observation and do not go out obvious brown stain, promoted the quality of garden stuff processing product largely, for China's fruit and vegetable processing industry is had laid a good foundation.The invention of this technology and enforcement will greatly promote the development of fruits and vegetables deep processing, have vast market prospect.

Claims (1)

1, a kind of method of utilizing the liquid nitrogen cryogenics deoxygenation to prevent the fruit and vegetable pulping brown stain is characterized in that carrying out according to following steps:

Select fruits and vegetables: decayed fruit is rejected in hand picking;

Clean: the spray drinking water cleans;

The blunt enzyme of microwave: select the microwave power of 700w-800w, passivation 60-80s, polyphenol oxidase under the double effect of microwave magnetic field and heating in the quick passivation fruits and vegetables and peroxidase also keep the nutrient of temperature-sensitive class simultaneously;

Peeling;

Precooling: the useless nitrogen that utilizes beater to discharge carries out precooling;

Chopping;

Spray nitrogen making beating: control the liquid nitrogen spray amount, measure the temperature and the dissolved oxygen of slurry automatically, utilize temperature control to realize deciding the making beating of dropping liquid nitrogen;

Allotment;

Homogeneous;

Sterilization: cold sterilization in the employing;

Make the fruit and vegetable jam product;

Aseptic packaging.