Poultry Processing Waste as an Alternative Source for Mammalian Gelatin: Extraction and Characterization of Gelatin from Chicken Feet Using Food Grade Acids.

The present study was focused on extraction of
gelatin from chicken feet using different food grade acids
(acetic-, citric- and lactic-acid) at different concentrations.
The gelatin thus obtained was evaluated for its physicochemical
properties. Gelatin yields in various acid treatments
ranged between 6.18 and 14.47% on wet weight
basis. The protein content of chicken feet gelatin (CFG)
obtained with different acid treatments was in the range of
80.53–90.20%; while, the pH was in the range of
3.43–5.23. Among all, CFG extracted with 1.5% (v/v)
acetic acid showed the highest bloom strength (204.3 g)
which was similar to commercial porcine gelatin. The CFG
prepared using 4.5% (v/v) citric acid had a bloom value of
165.8 g. The bloom strength of CFG prepared in our study
was relatively higher than fish gelatin and slightly lower
than porcine gelatin. Hydroxyproline content (g/100 g) of
CFG prepared using different acids was in the range of
4.58–9.5. The CFG contained glycine (*30%), imino
acids (proline ? hydroxyl proline; *25%) and alanine
(*9%) as the major amino acids. CFG, irrespective of the
acids used for preparation, exhibited moderate to strong
emulsifying and foaming capacities. The results clearly
indicate the potential of CFG to be an effective alternative
to mammalian gelatin.