OPTIMIZATION OF SUNFLOWER HUSKALKALINE DELIGNIFICATION PARAMETERS

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Abstract

The study is focused on optimizing alkaline delignification parameters for sunflower husks obtained during the seed hulling stage of preparing the raw material for oil extraction. Analysis of the sunflower husk chemical composition showed significant lignin levels (26,7 %). During the experiment, various factors which influence the delignification process, namely sodium hydroxide concentration (1 % to 5 %), sunflower husk particle size, temperature (20–100 ºС) and processing time (30 to 90 minutes) were studied. It was observed that the maximum fraction output of husk particles less than 3 mm in size amounted to 94,30% and was reached with the optimal sunflower husk milling time of 20 s using the ЛЦМ-1М experimental mill. It was demonstrated that alkaline solution concentration did not influence the degree of delignification when particle size exceeded 3 mm. While optimizing the alkaline delignification parameters, the most effective mode was determined to be the treatment of sunflower husks with particle size less than 3 mm with a 5 % sodium hydroxide solution at 80 ºС for 60 minutes. These conditions provide for both a high husk delignification degree (97 %) and conservation of a significant part of the fiber retained (22,84 %). The experimental findings are of scientific interest for further work involving the use of delignified husks as a medium for enzymolysis, which produces hydrolizates with a high output of fermented sugars.