Dairy Ingredients for Food Processing

326 Chapter 12

protein, generated using pepsin, trypsin, chy-

motrypsin, or other commercially available

proteases, resulted in high ACE inhibition

indices (i.e. 73% to 90%). Furthermore, the

active peptides were usually short (3 to 8

amino acids) and could be enriched from a

mixture of protein and other peptides using

ultrafi ltration with low - molecular - mass cut -

off membranes.

A tryptic peptide of β - lg (f142 to 148) was

further characterized following reversed -

phase chromatographic isolation and shown

to have an ACE IC50 value of 42.6 nM.

Similarly, several researchers have demon-

strated that a number of β - lg - derived pep-

tides have impressive ACE inhibitory activity

using a variety of in vitro assay techniques.

In a study in which whey proteins were

treated with different lactic acid starters and

digestive enzymes, it was reported that two

peptides from β - lg (f9 to 14 and f15 to 20),

following hydrolysis with trypsin or pepsin

and characterization by amino acid and MS -

analysis, had ACE inhibitory activity (Meisel,

1998 ). Four novel ACE inhibitory peptides

have been reported from caprine β - lg follow-

ing hydrolytic treatment with thermolysin

and purifi cation. It has been demonstrated

that a tetrapeptide isolated from β - lg (f142

to 145; Ala - Leu - Pro - Met), termed β - lactosin

B, had signifi cant anti - hypertensive activity

when administered orally to spontaneously

hypertensive rats (SHR) and therefore has

such as whey powder and various grades of
whey protein concentrate (WPC) and isolate
(WPI).
Isolation of whey proteins as spray -
dried whey powder and, in more limited
quantities, as whey protein concentrate/
isolate, has realized only a small portion of
the commercial potential of these proteins.
Indeed, whey protein concentrate, once her-
alded as a value - added outlet for whey solids,
is now considered a commodity item. In
addition, whey - protein - based products have
an unfortunate record of inconsistent and
unreliable performance in food systems.
Thus, expanded use of whey proteins relies
on exploitation of individual whey pro-
teins and their derivatives as products with
increased nutritional, functional, and/or bio-
logical value and increased commercial value
to the dairy industry. The emergence of new
technologies and methods provides fresh
insight into the bioactivity of these proteins
and produces new and sometimes surprising
results.
β - lg is the predominant protein in cheese
whey. Various peptides derived from proteo-
lytic digestion of β - lg have been shown to
have an inhibitory activity against angiotensin -
converting enzyme (ACE), which plays a
major role in the regulation of blood pressure
and thereby hypertension. It has been shown
that unhydrolyzed β - lg had very poor ACE
inhibitory activity, but that digests of the

Table 12.2. Currently marketed dairy products containing functional peptides.

Sample Peptide Product Function Producer

Calpis VPP/IPP Sour milk Hypotensive Calpis Co (JP)

Evolus VPP/IPP Fermented milk Hypotensive Valio (FI)

Capolac CPP Ingredient Mineral absorption AFI (DK)

PeptoPro NA Ingredient Recovery DSM Foods (NL)

tensVida IPP Ingredient Hypotensive DSM Foods (NL)

Cysteine Peptide Milk - protein -

derived peptide

Ingredient Raise energy and

sleep

FrieslandCampina (NL)

C12 FFVAPFPEVFGK Ingredient Hypotensive FrieslandCampina (NL)

PRODIET F200/

Lactium

TLGTLGGLLA Ingredient Anxiety reduction Ingredia (FR)

NOP - 47 NA Ingredient Vascular function Glanbia Nutritionals