Development of leather from the skin of yellowfin tuna (<em>Thunnus albacares</em>) and Asian sea bass (<em>Lates calcarifer</em>) using an environmentally friendly tanning technique

Abstract

Yellowfin tuna (Thunnus albacares) and Asian sea bass (Lates calcarifer) are highly demanded export fish species in Sri Lanka. The objective of the present study was to prepare leather from the skin of T. albacares and L. calcarifer using tanning media prepared with black tea (Camellia sinensis) powder and table salt (NaCl). Black tea powder and table salt concentrations were increased by 10 grams (initial weight; 10 gL-1) and 1 gram (initial weight; 1 gL-1), respectively each day for 12 d. Skins were dipped in each concentration for 24 hrs. After additional water was removed, vegetableoil-applied skins were stretched and air-dried at room temperature. The percentage of ash, fat,protein, and tensile strength of the leather prepared from L. calcarifer skin was significantly higher(P<0.05) compared to leather prepared from T. albacares skin. The percentage of moisture, averagethickness, and tear strength of the leather prepared from the T. albacares skin were significantlyhigher (P<0.05) than the leather prepared from L. calcarifer skin. According to the ΔL*, Δa*, andΔb* values, leather prepared from T. albacares skin has lighter, greener, bluer and L. calcarifer skinhas darker, greener, yellower colours respectively. There are no significant colour differences betweenprepared leathers (P>0.05). Sensory evaluation results indicated that, finishing, appearance,handling, and overall acceptability, of leather wallet prepared from T. albacares has higherconsumer acceptance. The study demonstrated the effectiveness of this novel method for preparationof leather from T. albacares and L. calcarifer skin. In conclusion, T. albacares skin is more suitablefor fish leather preparation using the above described tanning method.