Pea resistant starch preparation with cold-active type I pullulanase from Bacillus megaterium and its potential application in rice noodles
Zhishu Liu, Lulu Liu, Peng Han, Xiaobo Liang
Abstract
The characterization of PulY103B (pullulanase from Bacillus megaterium) was studied by our group, which showed that the enzyme is a cold-active type I pullulanase with a moderate active pH condition. The potential of PulY103B for resistant starch production in mild conditions (35 °C; pH 6.5) was investigated in this study. The result demonstrated that PulY103B was more efficient in pea resistant starch production with higher growth rate than the other pullulanases reported. The pea resistant starch (PS-PA) prepared with PulY103B had lower swelling power and solubility, and better thermostability. Also, the starch crystallinity pattern was different from the pea resistant starch reported earlier (B + V pattern: 5.9°, 17.0°, 19.2°, 21.9°, and 23.9°). Moreover, the PS-PA was used for preparing rice noodles (the best formula: PS-PA reached 8% rice granule weight). The results showed that the cooking properties of rice noodles were improved significantly (P < 0.05) including higher water absorption, lower cooking loss and breaking rate. The textural properties and its digestibility indicated that the rice noodle with PS-PA was suitable for children and elderly people who need weight loss.