Polypeptide powder, also known as albumin polypeptide powder, is the most abundant protein in human plasma protein. It accounts for 57%-63% of human plasma protein. The normal value of human albumin in China is recommended to be 35-55g/L. The following is what I have carefully prepared for you: A research paper on the production technology of almond polypeptide powder. The content is for reference only, welcome to read!

The production technology of almond polypeptide powder was studied as follows:

introduce

Almond is widely distributed in China, with many varieties and rich resources, with the largest output in Inner Mongolia, Jilin, Shaanxi and other places, and is the main variety of dried fruit export products in China. Almond is rich in high-quality protein, the content of which is about 20%, and the true digestibility and net protein rate are both high, among which isoleucine, threonine, tryptophan, valine, leucine and phenylalanine are close to or exceed the standard values of human essential requirements. The almond powder after oil pressing contains more than 40% protein.

Therefore, it is necessary to deeply process almonds and their by-products to improve the comprehensive utilization of almond resources. In this study, almond protein was deeply processed by enzymolysis technology, and almond polypeptide powder was developed to improve the functional characteristics and quality of almond protein and promote the development of almond protein deep processing.

1 materials and methods

1. 1 raw materials and accessories

The raw material is almond cake. Almond cake is a by-product of low-temperature extraction and degreasing of almond oil, with dense tissue, moisture 5%~8%, crude fat 10%~ 15%, carbohydrate 25%~30%, ash 3%~5% and protein 30%~40%. The content of crude fat in almond powder is 10%~ 15%. High oil content easily leads to protein emulsification during protein extraction, which affects the final yield of products. The oil content of almond powder should be controlled below 1%~5%.

Hydrolase, a compound hydrolase composed of exonuclease and endonuclease, was purchased from enzyme preparation company; Food-grade sodium hydroxide, in line with GB 5 175-85; Hydrochloric acid, food grade, conforms to GB 1897-2008.

1.2 test method

Protein was determined by Kjeldahl method GB/T14489.2—1993; The moisture content was determined by direct drying at normal pressure. The ash content is determined by mass method.

1.3 main equipment

Wet mill, leaching tank, centrifuge, plate heat exchanger, ultrafiltration device, double-effect falling film concentration device, spray drier and packaging machine.

Production technology of almond polypeptide powder

2. 1 process flow

Precipitation dissolution → alkali extraction → centrifugation → feed or fertilizer almond cake → wet grinding → alkali extraction → centrifugation → acid precipitation → centrifugation → precipitation neutralization → sterilization → enzymolysis → sterilization → membrane separation → retentate → blending → homogenization → sterilization flash evaporation → spray drying → cyclone separation → cooling screening → packaging → finished product.

2.2 almond polypeptide powder production technical requirements

2.2. Pretreatment of1almond cake

Take low-temperature pressed degreased almond cake, feed it into a wet mill with a quantitative feeder, add water and alkali solution while feeding, add hot water at 50-55℃ in the ratio of 1: 8 during grinding, and transport the wet crushed material liquid to a pre-soaking tank through a blender and a delivery pump, and adjust the pH value of the material liquid in the pre-soaking tank to 7.5-8.0.

2.2.2 Extraction of almond protein

Pumping the almond cake slurry in the pre-soaking tank into the leaching tank by centrifugal pump, stirring and leaching at 55℃ for 20~30 min, and centrifuging at the speed of 4 000 r/min to obtain supernatant.

Transfer that centrifuged heavy phase to a secondary extraction tank by a screw pump, adde water according to the ratio of 1∶4, adjusting the pH value to 7.5 with NaOH solution, repeatedly carry out secondary leaching, keeping the temperature at 55 DEG C, stirring and leaching for 20-30 minutes, and taking the supernatant after centrifugation.

After secondary centrifugation, pump the mixture into an acid precipitation tank in a clear liquid pipeline, adjust the pH value to 4.0~4.5 with hydrochloric acid online, stir for 65438±05 ~ 30min, then centrifuge at a speed of 4 000 r/min, and discard the supernatant, and the heavy phase is almond protein.

Add water to the precipitated almond protein, stir evenly to elute the acid, add water according to the ratio of 1: 4, and then centrifuge to obtain almond protein.

Neutralization and sterilization

The heavy phase after acid precipitation is neutralized by alkali solution, and the protein structure is unfolded by neutralization, and the sugar content is adjusted to 12% 0.5%, and the pH value is 7.5~8.0. Neutralization for 30 minutes, sterilization flash temperature of 65438 0 20℃, and discharge temperature of 60℃.

Enzymatic hydrolysis

Hydrolysis conditions: substrate mass fraction 10%~ 15%, enzyme addition 0.3%~0.5% of protein raw material mass, hydrolysis temperature 54~56℃, hydrolysis pH 7.5~8.0, maintained at pH 7.5 with alkali liquor during hydrolysis, and continuously stirred for 4 ~ 6h； hours; 85℃ 65438 00 min or plate heat exchanger can inactivate the enzyme.

Inactivate protease in raw material solution. After the enzymolysis liquid is filtered, it is heated by a plate heat exchanger, the feeding temperature is enzymolysis temperature, the enzyme inactivation temperature is 105℃, and the sterilization time is 5~ 10 s, so that the protease in the enzymolysis liquid is inactivated.

2.2.5 Membrane separation system

Centrifuge the hydrolyzed almond protein neutralized by inactivating enzyme to obtain centrifugal liquid. The centrifugal liquid is microfiltered by a continuous microfiltration membrane with a membrane aperture of 0.2 micron m. The content of almond polypeptide separated by ultrafiltration can reach 90%, and the content of polypeptide with molecular weight of 10 kDa can reach over 99%.

concentration

Almond polypeptide solution has high viscosity and belongs to heat-sensitive substances, so a double-effect falling film concentration device is selected. The feed liquid is added from the top of the heater. Under the action of gravity, the liquid flows downward along the inner wall of the tube in the form of liquid film. Due to downward acceleration, the accelerating head is smaller than the rising film type, and the boiling point is also smaller, and the temperature difference between heating steam and feed liquid is larger, so the heat transfer effect is better. The gas and liquid enter the evaporation separation chamber for separation, the secondary steam is discharged from the top of the separation chamber, and the concentrated solution is extracted from the bottom.

spray drier

After the almond polypeptide solution is concentrated, the pressure sprayer is selected, which consumes less electricity, and the energy per kilogram of solution is about 4 ~10 W. The product has large capacity and good solubility. When the exhaust temperature reaches 85℃, the pressure of high-pressure pump is 3~20 MPa, the rotating speed of sprayer nozzle is 15 000 r/min, the evaporation of water is 350 kg/h, the inlet temperature is 180℃, and the exhaust temperature is 80℃, spraying is started. After spray drying, it can be directly packaged. If the product needs to be uniform or caked, cyclone separation and cooling screening procedures are added to classify the product, and the classified product is packaged.

Cyclone separation is to remove the gas carried in polypeptide solid particles as much as possible to realize gas-solid separation. The air volume is 640~ 1 050 m3/h, and the wind speed is12 ~ 20m/s. The almond polypeptide powder gathers at the bottom, and the finer and lighter dust particles are picked up from the upper vortex airflow and transported to the bag filter for dust recovery. The filtration area of the bag filter is 18 m2, and the wind speed is 2~4 m/min. The dusty airflow enters the lower box from the air inlet and then partially precipitates. Slight dust is intercepted by the filter bag when it passes through the filter bag, and the gas enters the upper box and is discharged from the air outlet. Dust accumulates on the outer wall of the filter bag and increases continuously, and compressed air is ejected from the nozzle. Polypeptide powder recovered by cyclone separation and bag dust removal is collected in a temporary storage tank. Polypeptide has low molecular weight, low bulk density and easy to fall off powder, so the drying system must be intercepted by bag dust collector.

2.2.8 cooling and sieving

The polypeptide powder separated by cyclone is cooled in the fluidized bed device, and after the powder is discharged from the temporary storage tank, the movement of the powder is observed in the viewport of the fluidized bed, and the temperature of each section is adjusted in time to make the molecules move forward uniformly in a suspended state. The inlet temperature of the fluidized bed is 70℃, and the outlet temperature is 40℃. After cooling, the product was screened and packed with 100 mesh vibrating screen. If fluidized bed cooling device is not needed, it is necessary to extend the pipeline to fully cool the powder after spray drying, and then package it.

package

Powder packaging machine is used for packaging. According to the required packaging requirements, set the parameters of the packaging machine for quantitative packaging.

3 Conclusion

1 In order to benefit the final product yield, the oil content of almond cake should be controlled below 1%~5%.

2. Extracting almond protein by using protein's characteristics of alkali dissolution and acid precipitation, that is, dissolving the protein at pH 7.5~8.0, and then precipitating the protein at pH 4.5.

3 The optimum enzymolysis conditions are as follows: substrate concentration 10%~ 15%, enzyme dosage of 0.3%~0.5% of protein raw material, hydrolysis temperature of 54~56℃, hydrolysis pH of 7.5 ~ 8.0, and hydrolysis time of 4 ~ 6 h. ..

When the pore size of microfiltration membrane is 0.2 micron, the content of almond isolated polypeptide reaches 90%.

After spray drying, different specifications of packaging can be carried out according to different requirements.

The process has strong operability and is suitable for industrial production. ?