Abstract: in vitro binding studies of peanut oil to chitosan (CS) were carried out in stimulated digestive juice. Fat-binding characteristics of chitosan were investigated by measuring its fat-binding capacity (FBC) under various conditions. Meanwhile, the relationship of FBC with molecular structure for chitosan was analyzed. Chitosan showed an approximately 3-fold increase in FBC at pH 2—3 compared with pH 6.4—7.2. A higher FBC level was found for chitosan at 0.010—0.0067 g/mL in normal saline solution adjusted to pH 2 with hydrochloric acid. Similarly, middle molecular weight chitosan had a higher FBC level. The maximum FBC level was attained for chitosan when mixed with peanut oil at a mass ratio of 1:30. The FBC level of chitosan was dependent on its chain conformation. During the binding process, the FBC level of chitosan increased in the first 2 h, and then reached a plateau.

Key words: chitosan, fat-binding capacity, pH, conformation