Open AccessCo-valorization of agro-industry by-products: effect of citrus oil on the quality of soap derived from palm fatty acid distillate and spent bleaching clay
Author(s) -
Teerasak Punvichai,
Daniel Pioch
Publication year - 2019
Publication title -
letters in applied nanobioscience
Language(s) - English
Resource type - Journals
ISSN - 2284-6808
DOI - 10.33263/lianbs83.571575
Subject(s) - saponification , chemistry , distillation , pulp and paper industry , saponification value , yield (engineering) , organic chemistry , food science , fatty acid , materials science , engineering , metallurgy
This study deals with the co-valorization of spent bleaching clay (SBC) and palm fatty acid distillate (PFAD) –by-products of palm oil refining plants- through soap manufacture. Obtained SBC and PFAD samples show differing acidity and saponification values depending on fatty acids and acylglycerols content. Soaps are prepared using the stoichiometric amount of NaOH, under the varying proportion of water introduced through the basic solution. The mixing SBC and PFAD (ratio 1:3), the reaction completion (92.5%) is surprisingly higher than expected, indicating a synergistic effect on the course of the saponification reaction. The water is also a critical parameter, 30% w/w of added water allowing the highest yield. When testing for cleaning efficiency the products having the highest soap content, those from individual by-products give a low microbial count reduction after hand-washing (30-37%). But a much better score (74%) is obtained when using SBC:PFAD soap mixtures. This improvement could be due to abrasive and absorption effects of the clay, combined with the high soap content. The acceptability through a panel test is good for all soaps when formulated with citrus oil. The most active product corresponds to a SBC:PFAD ratio close to the production one in refining plants. Therefore these results provide an easy way for co-valorising these by-products, after further optimizing the saponification reaction in this complex triphasic medium (aqueous solution, oil, clay).