Collagen, extracted from various sources is widely used as a food supplement,
biomaterial and cosmetic material. It is usually extracted by acetic acid at low temperature (4
oC). Increasing the extraction temperature leads to an increase in process efficiency but likely
to affect collagen structure. Conventionally, acid soluble collagen (ASC) was separated from
acetic acid by salt precipitation followed by dialysis. However, this process is highly time
consuming. Therefore, this study aimed to investigate the effects of extraction temperature
and acid concentration on the extraction efficiency and collagen structure, and employed an
ultrafiltration (UF) to remove acetic acid and to concentrate ASC. ASC was extracted from
Nile tilapia skin at 5, 15 and 25
oC for 0-24 h with 0.3 or 0.5 M acetic acid. The extraction,
performed at 25 oC for 5 h with 0.5 M acetic acid gave the highest extraction efficiency
which higher than that at 5
oC about 1.7 folds without any effect on collagen triple helix
structure. The results also indicated strong effects of extraction temperature on extraction
efficiency. To remove the acid and concentrate the ASC, the discontinuous diafiltration
(DDF) mode was carried out followed by batch concentration mode (BC). The membrane
with MWCO 300 kDa was found to be the most suitable due to its higher flux. The acid
removal, higher than 95 % was achieved by using ultrafiltration. These results indicated that
the ASC was successfully produced using a hybrid process based on acid extraction and
ultrafiltration with higher efficiency compared to the conventional process.