Dairy Ingredients for Food Processing

Whey-based Ingredients 195

and is used as feedstock. The degree of

crystallization is determined by the quan-

tity of β - lactose that is converted to the

desired α - lactose form. Crystalline α -

lactose hydrate is hard and not very solu-

ble; β - lactose crystals are sweeter and

more soluble (Chandan 1997 ). According

to Harper (1992) , the following factors

are relevant in crystallization:

a. Original concentration of the lactose

in the solution

b. Concentration of the lactose in the

solution after crystallization has

taken place

c. Time and temperature of cooling

d. Level of impurities in the concentrate

e. Viscosity of the concentrate

f. Seeding material

The following factors are relevant to

separation (Harper 1992 ):

a. Homogeneity of the crystals

b. Viscosity

Lactose Processing, Products,

and Derivatives

Lactose is crystallized from whey or milk
permeates obtained by ultrafi ltration process-
ing. Lactose processing is similar to whey
powder processing in that it involves the
following:

1. Reverse osmosis of the whey permeate
   to 20% to 25%. Often this process is
   carried out under slightly acidic condi-
   tions to reduce the fouling caused by
   calcium phosphate salts.


2. Evaporation to 50% to 60% solids.
   Generally, falling fi lm evaporators are
   used in this step of the process. The con-
   centration that can be achieved depends
   on controlling scale formation caused by
   calcium salts (Harper 1992 ).


3. Crystallization followed by centrifuga-
   tion to separate the crystals. Impurities
   are washed from the lactose during sepa-
   ration. The residue is called mother liquor

Table 8.8. Potential health benefi ts of whey products and whey

components.

Health benefi t Component

Immunomodulation Lactoferrin

Lactoperoxidase

κ - Casein glycomacropeptide

Protection from some cancers WPC

Lactoferrin

α - Lactalbumin

Peptides

Sphingolipids

Protection from hypertension Peptides

Anti - infl ammatory Peptides

Colostrum

Anti - thrombotic activity Lactoferrin

Peptides

Reduction in cholesterol level WPC

Opioid - like activity Peptides

Prebiotics Casein glycomacropeptide

Oligosaccharides

Anti - oxidative effects WPC/WPI

Lactoferrin

Bovine serum albumin

Adapted from Harper (2001)