Chemistry Reference
In-Depth Information
*B
*D
*C
*A
Wash water
Dry salting
Whey
Milling
Milk
coagulation
soft curds
cheese
store
Cheese vat
Brining
Wash water
(Gouda, Edam,
Dambo)
*E
Fig. 5.1
Possible enzyme addition points (
*
) during the manufacture of hard and semi-hard cheese.
the cheese curd is separated, causing unacceptable losses to cheese yield. Also, the early
breakdown of caseins disrupts their orderly structure, prevents proper gel formation and
renders the curds too soft and unworkable in the later stages of curd acidification, prior to
salting and pressing into cheese. Add to these problems the loss of added enzymes into the
whey (at a rate of about 95%) and it is clear that addition of proteinases directly to the milk
is not an option. If peptidase preparations were very inexpensive, they could be added by
this route, but most large cheese plants sell their whey as concentrates to be added to foods
for their functionality. Any carry-over of ripening enzymes would have to be removed or
destroyed before the whey was processed and sold.
Enzyme microencapsulation is the obvious solution to the above problem, to protect ca-
seins in the milk and ensure physical entrapment of the enzymes in the curd gel matrix.
Options include fat, starch or gelatine capsules, but none of these has a satisfactory 'release'
mechanism in cheese. The author's research group developed a special type of phospho-
lipid liposomes
24, 25
as an effective technology to overcome this problem. Proteinases and
peptidases were entrapped in the liposomes and added to cheese milk. Most of the ripening
enzymes were entrapped in the water spaces of the curd particles and very little was lost in
the whey. The liposomes were degraded naturally in the cheese matrix after whey separation
and this allowed full contact between the protein matrix and the ripening enzymes. However,
although the technique has since been adopted in numerous experimental cheese trials,
26
the
high cost of the pure phospholipids necessary to make stable, high-capacity liposomes rules
this out as a large-scale commercial technology. More recently, liposomes have been available
commercially in the form of proliposome mixture (Prolipo-Duo
TM
, Lucas Meyer, France)
and used to put enzymes into Cheddar cheese.
27
However, an economical assessment of this
technology compared with the earlier work with 'home-made' liposomes has not been made
yet. Other approaches to proteinase encapsulation have been summarized by Kailasapathy
and Lam,
28
including the use of food-grade gums, and this seems to offer new opportunities
for cheese-like products. However, the cheese regulations in the major cheese-producing
countries would currently not permit gums as ingredients in natural cheese.
The semi-hard cheeses typified by Gouda and Edam are made by a process which includes
a curd 'washing' stage to replace some of the whey with water to reduce acidity. Although
this stage (point B in Fig. 5.1) and the soft curd stage (point C) offer a further opportunity
