Deboned chicken feet were soaked into 0.2% sodium hydroxide at
pH 13 for 2 h at 37oC and then soaked into 5% acetic acid at 37oC for
2 h for further extraction. The acid solution was drained and washed
with running tap water until pH neutral and the final extraction
of gelatin was performed in distilled water with 1% w/w of crude
papain extract at 37oC for 12 h. The extract then filtered through
two layers of cheese clothes and freeze dried. The dried matter was
ground as gelatin powder.