A Novel Eco-Friendly Process for the Synthesis and Purification of Ascorbyl-6-Oleates

Commercial ascorbyl-6-O-esters (AEs) are composed of saturated fatty acids with relatively high melting points, resulting in limited solubility in lipophilic media. Therefore, a lipase-catalysed synthesis and purification method for ascorbyl-6-O-oleate (AO) was proposed in this study. The esterifica...

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Main Authors: Ha-Eun Ji, Se-Young Kim, Heejin So, Vivian Prayitno, Ki-Teak Lee, Jung-Ah Shin
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/14/1/70
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author Ha-Eun Ji
Se-Young Kim
Heejin So
Vivian Prayitno
Ki-Teak Lee
Jung-Ah Shin
author_facet Ha-Eun Ji
Se-Young Kim
Heejin So
Vivian Prayitno
Ki-Teak Lee
Jung-Ah Shin
author_sort Ha-Eun Ji
collection DOAJ
description Commercial ascorbyl-6-O-esters (AEs) are composed of saturated fatty acids with relatively high melting points, resulting in limited solubility in lipophilic media. Therefore, a lipase-catalysed synthesis and purification method for ascorbyl-6-O-oleate (AO) was proposed in this study. The esterification synthesis (i.e., bonding of oleoyl group to ascorbic acid) rate was 19.7% using acetone as the reaction solvent. The transesterification synthesis (i.e., exchange of acyl group with oleic acid (OA) in ascorbyl-6-O-palmitate (AP)) rate increased to 73.8% (AP:OA = 1:3, molar ratio). The esterification product was purified sequentially by liquid–liquid extraction using ethyl acetate and water, followed by hexane and acetonitrile, resulting in 94.8 area% AO confirmed by HPLC. When acetonitrile was replaced with 90% methanol, AO achieved 97.2 area%. Similarly, the transesterification product showed 94.3 area% AEs (AP:AO = 8.9:91.1) after recrystallisation and liquid–liquid extraction. Finally, all purified AO revealed peaks corresponding to the hydroxyl groups at the C-2 and C-3 carbons (11.10 and 8.41 ppm, <sup>1</sup>H-NMR), whereas OA selectively esterified at the C-6 carbon (<sup>13</sup>C-NMR). FT-IR confirmed the presence of the ester bond (1733 cm<sup>−1</sup>) and olefin structure (3006 cm<sup>−1</sup>) of OA, and LC-ESI-MS/MS identified AO peaks at <i>m/z</i> 439.3. DSC analysis showed broad endothermic curves at 23.1–46.7 °C when the purified AO samples were pre-cooled at −25 °C.
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spelling doaj-art-4c7e1716b05a437abbab98b35a4bc6d12025-01-10T13:17:42ZengMDPI AGFoods2304-81582024-12-011417010.3390/foods14010070A Novel Eco-Friendly Process for the Synthesis and Purification of Ascorbyl-6-OleatesHa-Eun Ji0Se-Young Kim1Heejin So2Vivian Prayitno3Ki-Teak Lee4Jung-Ah Shin5Department of Food Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of KoreaDepartment of Food Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of KoreaDepartment of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, HI 96822, USADepartment of Food Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of KoreaDepartment of Food Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of KoreaDepartment of Marine Bio Food Science, Gangneung-Wonju National University, 7 Jukheon-gil, Gangneung 25457, Gangwon-do, Republic of KoreaCommercial ascorbyl-6-O-esters (AEs) are composed of saturated fatty acids with relatively high melting points, resulting in limited solubility in lipophilic media. Therefore, a lipase-catalysed synthesis and purification method for ascorbyl-6-O-oleate (AO) was proposed in this study. The esterification synthesis (i.e., bonding of oleoyl group to ascorbic acid) rate was 19.7% using acetone as the reaction solvent. The transesterification synthesis (i.e., exchange of acyl group with oleic acid (OA) in ascorbyl-6-O-palmitate (AP)) rate increased to 73.8% (AP:OA = 1:3, molar ratio). The esterification product was purified sequentially by liquid–liquid extraction using ethyl acetate and water, followed by hexane and acetonitrile, resulting in 94.8 area% AO confirmed by HPLC. When acetonitrile was replaced with 90% methanol, AO achieved 97.2 area%. Similarly, the transesterification product showed 94.3 area% AEs (AP:AO = 8.9:91.1) after recrystallisation and liquid–liquid extraction. Finally, all purified AO revealed peaks corresponding to the hydroxyl groups at the C-2 and C-3 carbons (11.10 and 8.41 ppm, <sup>1</sup>H-NMR), whereas OA selectively esterified at the C-6 carbon (<sup>13</sup>C-NMR). FT-IR confirmed the presence of the ester bond (1733 cm<sup>−1</sup>) and olefin structure (3006 cm<sup>−1</sup>) of OA, and LC-ESI-MS/MS identified AO peaks at <i>m/z</i> 439.3. DSC analysis showed broad endothermic curves at 23.1–46.7 °C when the purified AO samples were pre-cooled at −25 °C.https://www.mdpi.com/2304-8158/14/1/70ascorbyl-6-O-estersenzymatic esterificationenzymatic transesterificationrecrystallisationpurification
spellingShingle Ha-Eun Ji
Se-Young Kim
Heejin So
Vivian Prayitno
Ki-Teak Lee
Jung-Ah Shin
A Novel Eco-Friendly Process for the Synthesis and Purification of Ascorbyl-6-Oleates
Foods
ascorbyl-6-O-esters
enzymatic esterification
enzymatic transesterification
recrystallisation
purification
title A Novel Eco-Friendly Process for the Synthesis and Purification of Ascorbyl-6-Oleates
title_full A Novel Eco-Friendly Process for the Synthesis and Purification of Ascorbyl-6-Oleates
title_fullStr A Novel Eco-Friendly Process for the Synthesis and Purification of Ascorbyl-6-Oleates
title_full_unstemmed A Novel Eco-Friendly Process for the Synthesis and Purification of Ascorbyl-6-Oleates
title_short A Novel Eco-Friendly Process for the Synthesis and Purification of Ascorbyl-6-Oleates
title_sort novel eco friendly process for the synthesis and purification of ascorbyl 6 oleates
topic ascorbyl-6-O-esters
enzymatic esterification
enzymatic transesterification
recrystallisation
purification
url https://www.mdpi.com/2304-8158/14/1/70
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