Bioactive Components in Milk and Dairy Products - Prof. Dr. Aulanni ...

20 Section I: Bioactive Components in Milk
bacteria, augment phagocytosis of bacteria, kill bacteria
through activation of complement - mediated
bacteriolytic reactions, and neutralize toxins and
viruses.
The concentration of specifi c antibodies against
pathogenic microorganisms can be raised in colostrum
and milk by immunizing cows with vaccines
made of pathogens or their antigens (Korhonen
et al. 2000 ). Advances in bioseparation techniques
have made it possible to fractionate and enrich these
antibodies and formulate so - called immune milk
preparations (Mehra et al. 2006 ). The concept of
“ immune milk ” dates back to the 1950s when
Petersen and Campbell fi rst suggested that orally
administered bovine colostrum could provide
passive immune protection for humans (Campbell
and Petersen 1963 ). Since the 1980s, a great number
of studies have demonstrated that such immune milk
preparations can be effective in prevention of human
and animal diseases caused by different pathogenic
microbes, e.g., rotavirus, Escherichia coli, Candida
albicans, Clostridium diffi cile, Shigella fl exneri,
Streptococcus mutans, Cryptosporidium parvum,
and Helicobacter pylori . The therapeutic effi cacy of
these preparations has, however, proven to be quite
limited (Weiner et al. 1999 ; Korhonen et al. 2000 ;
Korhonen and Marnila 2006 ). A few commercial
immune milk products are on the market in some
countries, but the unclear regulatory status of these
products in many countries has emerged as a constraint
for global commercialization (Hoerr and
Bostwick 2002 ; Mehra et al. 2006 ). In view of the
globally increasing problem of antibiotic - resistant
strains causing endemic hospital infections, the
development of appropriate immune milk products
to combat these infections appears as a highly interesting
challenge for future research.
α - Lactalbumin
α - La is the predominant whey protein in human
milk and accounts for about 20% of the proteins in
bovine whey. α - La is fully synthesized in the
mammary gland where it acts as coenzyme for biosynthesis
of lactose. The health benefi ts of α - La
have long been obscured, but recent research suggests
that this protein can provide benefi cial effects
through a) the intact whole molecule, b) peptides of
the partly hydrolyzed protein, and c) amino acids of
the fully digested protein (Chatterton et al. 2006 ).
α - La is a good source of the essential amino acids
tryptophan and cystein, which are precursors of
serotonin and glutathion, respectively. It has been
speculated that the oral administration of α - La could
improve the ability to cope with stress. A human
clinical study with a group of stress - vulnerable subjects
showed that an α - La – enriched diet affected
favorably biomarkers related to stress relief and
reduced depressive mood (Markus et al. 2000 ). In a
later study the same researchers (Markus et al. 2002 )
observed that α - La improved cognitive functions in
stress - vulnerable subjects by increased brain tryptophan
and serotonin activity. In another clinical
study (Scrutton et al. 2007 ) it was shown that daily
administration of 40 g of α - La to healthy women
increased plasma tryptophan levels and its ratio to
neutral amino acids, but no changes in emotional
processing was observed. Furthermore, there is signifi
cant evidence from animal model studies that
α - La can provide protective effect against induced
gastric mucosal injury. The protection was comparable
to that of a typical antiulcer drug (Matsumoto
et al. 2001 ; Ushida et al. 2003 ). Bovine α - La hydrolysates
and specifi c peptides derived from these
hydrolysates have been associated with many
biological activities, for example, antihypertensive,
antimicrobial, anticarcinogenic, immunomodulatory,
opioid, and prebiotic (Pihlanto and Korhonen
2003 ; Chatterton et al. 2006 ).
Based on its high degree of amino acid homology
to human α - La, bovine α - La and its hydrolysates are
well suited as an ingredient for infant formulae.
A few α - La enriched formulae have already been
launched on the market.
β - Lactoglobulin
β - Lg is the major whey protein in bovine milk and
accounts for about 50% of the proteins in whey, but
it is not found in human milk. β - Lg poses a variety
of functional and nutritional characteristics that have
made this protein a multifunctional ingredient material
for many food and biochemical applications.
Furthermore, β - Lg has been proven an excellent
source of peptides with a wide range of bioactivities,
such as antihypertensive, antimicrobial, antioxidative,
anticarcinogenic, immunomodulatory, opioid,
hypocholesterolemic, and other metabolic effects
(Pihlanto and Korhonen 2003 ; Chatterton et al.
2006 ). Of particular interest is the antihypertensive