title: Onion skin waste as a valorization resource for the by-products quercetin and biosugar.
abstract: Onion skin waste (OSW), which is produced from processed onions, is a major industrial waste. We evaluated the use of OSW for biosugar and quercetin production. The carbohydrate content of OSW was analyzed, and the optimal conversion conditions were evaluated by varying enzyme mixtures and loading volumes for biosugar production and quercetin extraction. The enzymatic conversion rate of OSW to biosugar was 98.5% at 0.72 mg of cellulase, 0.16 mg of pectinase, and 1.0mg of xylanase per gram of dry OSW. Quercetin extraction also increased by 1.61-fold after complete enzymatic hydrolysis. In addition, the newly developed nano-matrix (terpyridine-immobilized silica-coated magnetic nanoparticles-zinc (TSMNP-Zn matrix) was utilized to separate quercetin from OSW extracts. The nano-matrix facilitated easy separation and purification of quercetin. Using the TSMNP-Zn matrix the quercetin was approximately 90% absorbed. In addition, the recovery yield of quercetin was approximately 75% after treatment with ethylenediaminetetraacetic acid.
authors.affiliation: Bio-energy Research Center, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: In Seong
authors.initials: IS
authors.lastname: Choi
authors.affiliation: Bio-energy Research Center, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Eun Jin
authors.initials: EJ
authors.lastname: Cho
authors.affiliation: Department of Food Science and Technology and Functional Food Research Center, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Jae-Hak
authors.initials: JH
authors.lastname: Moon
authors.affiliation: Bio-energy Research Center, Chonnam National University, Gwangju 500-757, Republic of Korea; Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea. Electronic address: baehj@chonnam.ac.kr.
authors.forename: Hyeun-Jong
authors.initials: HJ
authors.lastname: Bae
mesh_terms: D002480:Cellulase; D006868:Hydrolysis; D007220:Industrial Waste / Q000032:analysis*; D019697:Onions / Q000737:chemistry*; D011794:Quercetin / Q000737:chemistry*
chemical_list: D007220:Industrial Waste; D011794:Quercetin; D002480:Cellulase
keywords: Enzymatic hydrolysis; Nano-matrix; Onion skin waste; Quercetin