Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Lloyd Metzger


Delactosed Permeate, Lactose Crystallization, Mother Liquor, Nanofiltration


Delactosed permeate (DLP), commonly referred to as mother liquor, is a plentiful byproduct in the dairy industry. It is a direct byproduct of edible lactose manufacture produced in cheese and dairy ingredient facilities. Despite being rich in lactose and minerals, DLP is most commonly relegated to an animal feed product due to its high ash content, it inhibits and disallows crystallization of any remaining lactose. Delactosed permeate showed many inconsistencies from supplier to supplier and within lots from the same supplier in the eight DLP samples obtained from four separate mozzarella and cheddar manufacturing facilities. Nanofiltration (NF) opens potential food applications for DLP. The eight DLP samples obtained were processed via NF creating two separate product streams. A retentate (NFR) with increased lactose concentrations on a dry basis in addition to increased concentrations of large molecular weight minerals and organic acids (Ca, Mg, S, citric acid). In addition to, a permeate rich in small molecular weight minerals and organic acids (Cl, Na, K, lactic and formic acid). Flux rate and the composition of retentates/permeates varied from trial to trial and is likely due to different milk compositions, cheese making practices, whey handling practices and lactose manufacturing methods.

Library of Congress Subject Headings

Dairy processing -- By-products.
Dairy products in human nutrition.



Number of Pages



South Dakota State University



Rights Statement

In Copyright