Whey-based Ingredients 181- Use of rennet (chymosin) in cheese and
rennet casein manufacture adds glycomac-
ropeptide to the whey stream. This protein
fraction is not present in whey streams
derived from the direct acidifi cation or the
microfi ltration of skim milk. GMP increases
the protein content of the whey fraction
and changes its functional properties by
diluting the effects of β - lactoglobulin and
α - lactalbumin. - Cheese type impacts pH, total solids, and
mineral and fat contents; cheese manufac-
ture also adds cheese fi nes, various protein
peptides, enzymes, and starters. - Use of direct acidifi cation leads to a whey
stream with higher mineral content and
adds acid ions that change the fl avor and
functional properties of the whey. - In general, casein whey, which is made
from skim milk, has lower fat content than
cheese whey, made from whole milk. This
difference in initial whey fat is reduced by
separation of the fat from cheese whey
during whey treatment. - Whey protein from the microfi ltration of
skim milk typically has no measurable fat
and may contain small amounts of casein
proteins (Oestergaard, no date; Marcelo
and Rizvi 2008 ). - Seasonal variation in the composition of
milk and whey affects dairy herds that are
grass fed and receive minimal supplemen-
tary feeding. Calving occurs in spring and
between $1.50/kg and $280/kg. The place-
ment of the bubble in relation to the Y axis
is related to its total global production, as
given by Affertsholt and Nielsen (2007).
Whey Sources and Composition
Whey is a dilute liquid containing approxi-
mately 6% solids, of which approximately
5.4% is lactose and 0.7% is protein. The
whey protein is a complex mixture of β -
lactoglobulin ( β - lg; approximately 55%), α -
lactalbumin ( α - lac; approximately 24%),
bovine serum albumin (BSA; approximately
5%), immunoglobulins (approximately 15%),
and several other minor proteins (Swaisgood
1996 ). Whey also can include more than
20% glycomacropeptide (GMP) if the whey
is from cheese manufacture (Regester and
Smithers 1991 ).
Whey produced from cheese and rennet
casein is known as sweet whey; whey pro-
duced from direct acidifi cation (e.g., from
cottage cheese or acid casein manufacture) is
known as acid whey. Whey produced from
the microfi ltration of skim milk is yet to
receive a standard of identity; it has been
named serum protein, soluble milk protein,
and native WPI (Marcelo and Rizvi 2008 ,
Zulewska et al. 2009 ). The whey composi-
tions are shown in Table 8.1.
Whey composition is variable and depends
on a number of factors (Abd El - Salam et al.
2009 ):
Table 8.1. Typical composition of whey streams.
Sweet whey Acid whey Soluble whey protein
from microfi ltration
% Total solids 6.4 ± 0.4 6.4 ± 0.4 5.8 ± 0.3
% Protein 0.85 ± 0.05 0.7 ± 0.2 0.55 ± 0.05
% Lactose 5.0 ± 0.1 4.6 ± 0.3 4.6 ± 0.2
% Fat 0.06 a – 0.4 b < 0.05 a Not detected
% Ash 0.65 ± 0.05 0.75 ± 0.05 0.55 ± 0.05
% Calcium 0.04 – 0.05 0.15 ± 0.5 No data
pH 5.9 ± 0.2 4.5 ± 0.1 6.6 ± 0.1a After separation
b Before separation
Adapted from Zadow (1992), Anon (2004) , Kilara (2008)