Method for preparing whey protein powder (WPC) and lactose powder simultaneously by whey

Abstract

The invention belongs to a production technology of a dairy product and particularly relates to a method for preparing WPC and lactose powder simultaneously by whey. The main steps are as follows: (1) primary ultrafiltration: a whey solution passes through an ultrafiltration membrane with the molecular weight cutoff of 5,000 to 10,000Da; (2) moisturization and ultrafiltration: when the membrane flux is reduced to 60% to 80% of the primary membrane flux, continuously supplementing 2 to 5 times of deionized water based on the volume of a concentrated solution into the concentrated solution to obtain a permeate and the concentrated solution; (3) preparing the whey protein powder: ultrafiltrating and drying the whey protein powder to obtain the WPC; and (4) refining the lactose powder: adding the evaporated and condensed ultrafiltration permeate into food grade ethanol till the final volume fraction is 40 to 60%, collecting, washing and drying the precipitate to obtain the lactose. According to the method for preparing the WPC and the lactose powder simultaneously by the whey, WPC with high protein content and lactose powder with high purity are obtained simultaneously through the ultrafiltration as a main separating method, and the deionized water and the food grade ethanol are only added in the whole process but the substances including external salt, acid and alkali and the like are not added.

Description

technical field [0001] The invention relates to a method for preparing whey protein powder and lactose powder from whey liquid, belonging to the field of dairy processing. Background technique [0002] After the casein is separated from milk to make cheese, the remaining solution is whey. As a by-product, whey liquid has high water content and is inconvenient to transport. It is often made into sweet whey powder by spray drying and other methods. Sweet whey powder mainly contains lactose (about 70%) and whey protein (about 10%). [0003] Lactose is a disaccharide secreted by the mammalian mammary gland, which is formed by the condensation of one glucose and one galactose, and has two conformations, α and β. Lactose products are basically extracted from whey, which can be used in baby food, candy, artificial milk, etc., and is often used as a flavoring agent in medicine. Due to the high incidence of lactose intolerance among Chinese residents, it is usually necessary to se...

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Problems solved by technology

[0006] Chinese patent CN 101926408 A uses microfiltration to simply divide milk into casein-rich concentrate and whey permeate with uniform composition, which simplifies the standardization process of cheese milk, but does not further process the whey product

[0008] In Chinese patent CN 101367864 A, hydrophobic interaction chromatography and gel filtration chromatography are used to separate whey protein. Anions and cations such as ammonium sulfate and phosphate buffer are introduced in the chromatography process, and the waste liquid generated needs to be treated and discharged. The separation medium Expensive, high preparation cost

[0010] Chinese patent CN 101822309 A discloses a production method for producing whey protein and its products by hollow fiber membrane ultrafiltration. The protein content in the product is only 15% ± 0.5%, which cannot reach whey protein concentrate WPC 70 (protein content ≥70%) and WPC 80 (protein content ≥80%)

The protein content is not disclosed, and the whole process has many steps and takes a long time

[0012] In the preparation methods disclosed in existing patents, the protein content in the final product whey protein is generally low, and generally does not meet the relevant standards of whey protein concentrate WPC, and is not suitable for addition to baby food, etc.

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