Valorization of Agro-Industrial Residues: Bioprocessing of Animal Fats to Reduce Their Acidity

Adding value to agro-industrial residues is becoming increasingly important, satisfying needs to promote resources’ use efficiency and a more sustainable and circular economy. This work performs a parametric and kinetic study of enzymatic esterification of lard and tallow with high acidity, obtained...

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Bibliographic Details
Published in:Sustainability
Main Authors: António A. Martins, Soraia Andrade, Daniela Correia, Elisabete Matos, Nídia S. Caetano, Teresa M. Mata
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2021
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Online Access:https://doi.org/10.3390/su131910837
https://doaj.org/article/295bb05e967b4551933af3d7554d9fa2
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Summary:Adding value to agro-industrial residues is becoming increasingly important, satisfying needs to promote resources’ use efficiency and a more sustainable and circular economy. This work performs a parametric and kinetic study of enzymatic esterification of lard and tallow with high acidity, obtained by the rendering of slaughter by-products, allowing their use as a feed ingredient and increasing their market value. After an initial analysis of potential enzyme candidates, a Candida antarctica lipase B was selected as a biocatalyst for converting free fatty acids (FFA) to esters, using excess ethanol as the reagent. Results show that the fat acidity can be reduced by at least 67% in up to 3 h of reaction time at 45 °C, using the mass ratios of 3.25 ethanol/FFA and 0.0060 enzyme/fat. Kinetic modelling shows an irreversible second-order rate law, function of FFA, and ethanol concentration better fitting the experimental results. Activation energy is 54.7 kJ/mol and pre-exponential factor is 4.6 × 10 6 L mol −1 min −1 .