CN105876073A - Preparation method of soybean protein - Google Patents

Abstract

The invention relates to a preparation method of soybean protein, and belongs to the fields of processing of agriculture products and biochemical inhibition of enzymes. According to the preparation method disclosed by the invention, low temperature degreased soybean meal is used as raw materials, through heat treatment, the vitality of lipoxygenase in the soybean meal is reduced to an appropriate extent, and the treated soybean meal is suspended in an aqueous solution in a certain solid-to-liquid ratio; the temperature and a pH value are adjusted, and through alkali fusion, acid precipitation and curd separation, the soybean protein is obtained. According to the preparation method disclosed by the invention, the lipoxygenase is a major factor causing the lipid peroxidation of residues of the soybean meal, after heating enzyme deactivation treatment of different degrees is performed, the vitality of the lipoxygenase in the soybean meal is gradually reduced, and functional performances of the solubility, the gel coagulation performance and the like are improved. After the heating enzyme deactivation treatment is performed on the soybean meal, the functional performances of the nitrogen soluble index, the gel strength and the like of the products namely the soybean protein are also greatly improved.

Description

A kind of preparation method of soybean protein

Technical field

The present invention relates to a kind of bean cake preparation method through the soybean protein of heat treated, belong to processing of farm products Biochemical suppression field with enzyme.

Background technology

Along with the demand in domestic soybean protein market and improving constantly of yield, the raising of soybean protein functional character Become an urgent demand of numerous domestic Protein processing factory.With more external famous large-scale soybean protein manufacturers, as ADM, only oils and fats, central authorities Semen sojae atricolor etc. are compared, no matter the kind of albumen or quality, and domestic product is all gone back Differ from it by bigger class.It is middle-size and small-size greatly that this gap is little in many production scales, research and development of products ability is weak In soybean protein manufacturing and processing enterprise especially prominent.Carefully analyze and affect the functional qualitative factor of soybean protein, mainly Have: 1) soybean varieties, 2) the plantation area natural cause such as water and soil, weather, 3) processing mode of defatted soybean meal and Technique, including degreasing method (squeeze, extract, CO₂Supercritical extraction etc.), skimming temp, degreasing time with And the residual oil content etc. of defatted soybean meal, 4) processing mode of soybean protein and technological parameter, such as solid-liquid ratio, extraction temperature Degree, extraction time, pH etc..Wherein 1) and 2) belong to naturality factor, selection-breeding elite soybean product can be passed through Kind, the mode such as enhancement of field management obtains High quality processing raw material, is available for for soybean protein processing enterprise The leeway controlled is little；3) and 4) then belong to post-production link, by select rational technological process and Parameter can make up the impact of raw material to a great extent, and can improve the functional character of soybean protein.

An easy unheeded link is had, it is simply that defatted soybean meal extracts big in the soybean protein course of processing The Passivation Treatment of soybean protein preferment.Semen sojae atricolor is rich in multiple enzyme system, such as lipoxidase, urease, amylase etc., Wherein the content of lipoxidase is the highest, accounts for 1～2% of protein content in Semen sojae atricolor.Due to lipoxidase Can be catalyzed containing suitable, the unsaturated fatty acid of cis-1-4-pentadiene structure and esters, and generate hydroperoxidation fat Class, can produce a large amount of free radical in the process.This place that soybean protein is worth arousing attention in processing just, Bean cake is through ungrease treatment, although most neutral lipids are removed, but a small amount of polar lipid is with remnants' Neutral lipid can remain.In later stage ground protein extraction, these remaining lipids are with the lipoxidase in bean cake Enzyme can interact in the molten step of alkali, and the temperature of the environment of lixiviating solution meta-alkalescence and 40～50 DEG C is especially The optimal condition of lipoxidase.The a large amount of free radicals produced the most in this process can promote Semen sojae atricolor Albumen is assembled.This bulky, loosely organized aggregation can have a strong impact on the functional of soybean protein Matter.

Summary of the invention

It is an object of the invention to provide the preparation method of a kind of soybean protein, made by the pretreatment to bean cake The soybean protein functional character extracted is improved.

The preparation method of soybean protein of the present invention, is with defatted soybean meal as raw material, through heat treated Making the vigor of lipoxidase in bean cake be reduced to suitable degree, the bean cake after process suspends with certain solid-to-liquid ratio In aqueous solution, regulation temperature and pH, molten through alkali, sour heavy and curdled milk isolated soybean protein, described side Method is:

1) heat treated: include xeothermic, saturated vapor heating or microwave treatment,

Xeothermic enzyme denaturing processes: raw material carries out conditioning to 10%～14%, heating-up temperature 90～110 DEG C, Heat time heating time 1～30min；

Or with steam enzyme denaturing process: regulation steam temperature be 70～100 DEG C, heat time heating time 10s～20min；

Or by microwave treatment: microwave treatment amount is 100 grams of bean cake, and microwave power is 100～400W, at microwave The reason time is 5～80s；

2) bean cake after processing uses conventional method to be suspended in aqueous solution with solid-to-liquid ratio 1: 10～1: 20g/ml In, regulation temperature 30～60 DEG C, at pH7.0～9.0 alkali molten 30～60min, it is centrifugally separating to obtain supernatant, Supernatant regulation pH 4.0～benzothiophene acid sink, and are centrifugally separating to obtain curdled milk, and curdled milk is freezing after readjustment pH 7.0 It is dried or is spray-dried and obtain soy protein products.

Beneficial effects of the present invention:

The existence that present invention discover that lipoxidase is the principal element causing bean cake remnants lipid peroxidation, passes through After heating enzyme denaturing in various degree processes, in bean cake, the vigor of lipoxidase progressively declines, its dissolubility, solidifying The functional characters such as colloidality are improved.Bean cake through heating enzyme denaturing process after, the nitrogen soluble index of soybean protein and The functional characters such as gel strength all improve a lot.

Detailed description of the invention

Embodiment 1

Taking defatted soybean meal, after pulverizing, adjusting water content content is to 10.2%, loads tool plug screw-cap test tube, close Being honored as a queen and heat enzyme denaturing 30min in 110 DEG C, ice bath is cooled to room temperature immediately.Take this bean cake and measure lipoxidase Vigor be about 400U/mg.Extract with this bean cake and separate albumen, solid-liquid ratio 1: 10g/ml, temperature 30 DEG C, at the pH 7.0 molten 60min of alkali, the heavy pH 4.0 of acid, curdled milk is score through readjustment pH7.0 postlyophilization From albumen.The nitrogen soluble index (NSI) measuring separation albumen is 91%.Measure the gel strength separating albumen again, With the protein solution of this separation albumen preparation 12%, heating 15min at 90 DEG C, ice bath is cooled to room temperature, is formed Gel after 4 DEG C of refrigerators are aged 24h, measure gel strength with property tester, its intensity is 206g.

Embodiment 2

Taking defatted soybean meal, after pulverizing, adjusting water content content is to 14%, loads tool plug screw-cap test tube, seals After in 90 DEG C heat enzyme denaturing 1min, ice bath is cooled to room temperature immediately.Take this bean cake and measure the work of lipoxidase Power is about 350U/mg.Extract with this bean cake and separate albumen, solid-liquid ratio 1: 20g/ml, temperature 60 C, The molten 30min of pH9.0 alkali, the heavy pH5.0 of acid, curdled milk is spray-dried after readjustment pH7.0 and must separate albumen. The nitrogen soluble index (NSI) measuring separation albumen is 92%.Measure the gel strength separating albumen again, with this point From the protein solution of albumen preparation 12%, heating 15min at 90 DEG C, ice bath is cooled to room temperature, the gel of formation Measuring gel strength with property tester after 4 DEG C of refrigerators are aged 24h, its intensity is 220g.

Embodiment 3

Take defatted soybean meal, uniform spreading a thin layer on steam rack, the saturation vapour temperature of regulating thermostatic steam kettle It is 100 DEG C, is placed in pot by steam rack rapidly that airtight steam pot cover takes out steam rack and is cooled to room temperature after 10s, Measuring lipoxidase enzyme activity after natural drying is about 150U/mg.Extracting and separate albumen, method is with implementing Example 1, the NSI value measuring separation albumen is 95%.Measuring 12% gel strength (condition is with embodiment 1) is 315g。

Embodiment 4

Take defatted soybean meal, uniform spreading a thin layer on steam rack, the saturation vapour temperature of regulating thermostatic steam kettle It is 70 DEG C, is placed in pot by steam rack rapidly that airtight steam pot cover takes out steam rack and is cooled to room temperature after 20min, Measuring lipoxidase enzyme activity after natural drying is about 50U/mg.Extracting and separate albumen, method is with implementing Example 1, the NSI value measuring separation albumen is 95%.Measuring 12% gel strength (condition is with embodiment 1) is 356g。

Embodiment 5

Take 100 grams of defatted soybean meals, add and small beaker is sealed up preservative film, regulate microwave generator power 100W, controls microwave heating time 80s, takes out beaker and cools down rapidly, measures fat after temperature is down to room temperature Oxygenase vigor is about 75U/mg.Extracting and separate albumen, method, with embodiment 1, measures and separates albumen NSI value is 93%.Measuring 12% gel strength (condition is with embodiment 1) is 303g.

Embodiment 6

Take 100 grams of defatted soybean meals, add and small beaker is sealed up preservative film, regulate microwave generator power 400W, controls microwave heating time 5s, takes out beaker and cools down rapidly, measures fat after temperature is down to room temperature Oxygenase vigor is about 80U/mg.Extracting and separate albumen, method, with embodiment 1, measures and separates albumen NSI value is 89%.Measuring 12% gel strength (condition is with embodiment 1) is 290g.

Embodiment 7

The present embodiment is reference examples, takes defatted soybean meal, and the vigor directly measuring lipoxidase is 4240U/mg.Take this bean cake with embodiment 1 method preparative separation albumen, mensuration NSI value and the gel of 12% Intensity, respectively 83% and 37g.

Claims (1)

1. a preparation method for soybean protein, is characterized in that with defatted soybean meal as raw material, at heating Reason makes the vigor of lipoxidase in bean cake be reduced to suitable degree, and the bean cake after process hangs with certain solid-to-liquid ratio Float in aqueous solution, regulation temperature and pH, molten through alkali, sour heavy and curdled milk isolated soybean protein, described Method is:

1) heat treated: include xeothermic, saturated vapor heating or microwave treatment,

Xeothermic enzyme denaturing processes: raw material carries out conditioning to 10%～14%, heating-up temperature 90～110 DEG C, Heat time heating time 1～30min；

Or with steam enzyme denaturing process: regulation steam temperature be 70～100 DEG C, heat time heating time 10s～20min；

Or by microwave treatment: microwave treatment amount is 100 grams of bean cake, and microwave power is 100～400W, at microwave The reason time is 5～80s；

2) bean cake after processing uses conventional method to be suspended in aqueous solution with solid-to-liquid ratio 1: 10～1: 20g/ml In, regulation temperature 30～60 DEG C, at pH7.0～9.0 alkali molten 30～60min, it is centrifugally separating to obtain supernatant, Supernatant regulation pH 4.0～benzothiophene acid sink, and are centrifugally separating to obtain curdled milk, and curdled milk is freezing after readjustment pH 7.0 It is dried or is spray-dried and obtain soy protein products.