An extensive amount of research has reported on the use of ultrafiltration (UF) membrane,
particularly in the improvement of membrane performance efficiency on cow’s milk. However,
a very limited number of researches reported on using UF for producing low-lactose goat’s
milk due to inherently low lactose. Nonetheless, goat’s milk is still not suitable to be consumed
in a large amount by people who are lactose intolerant, especially among Asians, where
over 90% of the populations are suffering from lactose intolerance. Until today, fouling and
concentration polarization (CP) on membrane surface in cross-flow hollow fiber UF unit are
the major problems in the dairy industry. Discovery on how to overcome the problem is still
in a hot debate due to the nature’s complex composition in milk. One way to overcome this
problem is by evaluating the effects of processing parameters such as trans-membrane pressure
(TMP) and feed-flow rate on flux (J), lactose rejection (Ri), concentration factor (CF), and
accumulation rate (AR) during the fractionation of lactose. In terms of lactose fractionation for
5 KDa and 10 KDa UF membranes, the TMPs examined were 0.41, 0.55, and 0.69 bars, while
feed flow-rates examined were 0.18, 0.34, 0.54, and 0.74 L/min. 5 KDa membrane shows that
feed flow-rate and flux behave in a direct relationship, while an inverse relationship in 10 KDa
membrane. Both membranes showed that TMP 0.55 bar exhibit the best flux value without
reaching the limiting flux region, but with feed flow rate of 0.74 L/min in 5 KDa, while 0.18
L/min in 10 KDa membrane. Lactose rejection percentage (%Ri) is the lowest with 77.71% in
5 KDa membrane while 66.28% in 10 KDa membrane. This can be summarized that the best
parameters for 5 KDa membrane is at TMP 0.55 bar with feed flow-rate of 0.74 L/min, while
for 10 KDa membrane is at TMP 0.55 bar with feed flow-rate of 0.18 L/min. Due to higher flux
value and lowest lactose rejection obtained from low feed flow-rate, 10 KDa UF membrane
size was chosen over 5 KDa. As a conclusion, a high degree of lactose removal from goat’s
milk could be achieved by 10 KDa UF membrane in a cross-flow hollow fiber system, which
proved that different outcomes between 5 KDa and 10 KDa membranes and feed flow-rate
required is closely associated to UF pore size and molecular weight of feed solute particles.