Compositions of the deposit formation found at different operating
temperatures are listed in Table 4. The analysis has revealed
that increasing inlet temperature of coconut milk (50 C, 60 C, and
70 C) resulted in an increase in percentage of protein found in the
deposit (4.6%, 5.8%, and 7.9%). Some previous works can be referred
that proteins in coconut milk were found to play an important role
on the stability of the milk at high temperatures. Seow & Goh [21]
found that the thermal denaturation of the coconut milk protein
can occur over the range of temperature 50e130 C. Peak of
denaturation temperatures were found at about 92 and 110 C.
Buccat, Gonzalez & Manalac [25] reported that the coagulation of
protein starts at about 60 C. There is also a report by Hagenmaier
[30] indicated that denaturation and coagulation of most of the
coconut milk proteins occurs at 80 C. In this case, the coagulation
of complex proteins at or near heating surface can lead to chemical
reaction fouling similar to the fouling process of dairy products.
However, percentage of proteins in coconut milk solution is much
less than that of dairy solutions. Percentage of proteins found in
coconut milk fouling deposit is then much less than that of type A
cow milk fouling deposit, i.e. protein 50e60%