Use of starch and actived tigernut by-product from the extraction of tigernut (Cyperus esculentus) milk for the purification of used cooking oils

The management of used cooking oils represents a real economic and environmental challenges. The search for bioadsorbents allows for the pre-treatment of used oils suitable for reuse. Tigernuts starch and by-product from the extraction of tigernut milk are used as bioadsorbent in the purification of used oil. The objective of this study is to reduce the acid and peroxide values. Used oil is treated with 8 and 12% starch during 10, 20, 30 and 40 min heating. Activated by-product were used as adsorbent at 1 and 2% after adsorption with starch. The results show abatement rates ranging from 1.65 to 27.51% for the acid value and from 39.16 to 73.48% for the peroxide value for 8% starch. Reductions rate of 23.50 to 34.44% and 58.06 to 71.33% respectively for the acid and peroxide values during treatment with 12% starch. The oil pre-treated with 8% starch shows an acid number reduction from 28.58 to 38.40% with 1% residue. Peroxide value shows reductions of 75.74 to 80.15% with 1% residue and 77.37 to 80.66% with 2% residue. The pre-treatment with 12% starch shows an acid value reduction ranging from 27.88 to 49.01% and from 14.0 to 35.08% with 1 and 2% residues. The peroxide value abatement ranges from 60.26 to 85.12% and from 77.37 to 87.33% with 1 and 2% residues. Tigernut starch can be used to purify used frying oils. However, its effectiveness is seen more in reducing the peroxide value. The combination of activated by-product and starch is more effective.