Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional Applications

Squid viscera, a byproduct of squid processing, contains oil rich in omega-3 fatty acids (up to 10% by mass) and the antioxidant astaxanthin. However, its high free fatty acid (FFA) content compromises stability. To address this, pilot-scale (200 L) enzymatic re-esterification of squid oil using imm...

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Main Authors: Asavari Joshi, Brendan Holland, Moninder Sachar, Colin J. Barrow
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Marine Drugs
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Online Access:https://www.mdpi.com/1660-3397/23/1/21
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author Asavari Joshi
Brendan Holland
Moninder Sachar
Colin J. Barrow
author_facet Asavari Joshi
Brendan Holland
Moninder Sachar
Colin J. Barrow
author_sort Asavari Joshi
collection DOAJ
description Squid viscera, a byproduct of squid processing, contains oil rich in omega-3 fatty acids (up to 10% by mass) and the antioxidant astaxanthin. However, its high free fatty acid (FFA) content compromises stability. To address this, pilot-scale (200 L) enzymatic re-esterification of squid oil using immobilized lipase (Lipozyme RMIM) was demonstrated, resulting in high acylglyceride yields. The processed oil was analyzed for oxidation kinetics and thermodynamics using Rancimat, fatty acid composition using GC, omega-3 fatty acid positional distribution in the acylglyceride product using <sup>13</sup>C NMR, and astaxanthin content. Lipase treatment reduced FFA levels from 44% to 4% and increased acylglycerides to 93% in squid oil. This reduction in FFA was accompanied by significantly increased stability (0.06 to 18.9 h by Rancimat). The treated oil showed no loss in astaxanthin (194.1 µg/g) or omega-3 fatty acids, including docosahexaenoic acid (DHA). DHA remaining predominantly at sn-2 indicated that the naturally occurring positional distribution of this omega-3 FFA was retained in the product. Lipase treatment significantly enhanced oxidative stability, evidenced by improved thermodynamic parameters (E<sub>a</sub> 94.15 kJ/mol, ΔH 91.09 kJ/mol, ΔS −12.6 J/mol K) and extended shelf life (IP<sub>25</sub> 74.42 days) compared to starting squid oil and commercial fish/squid oils lacking astaxanthin. Thus, lipase treatment offers an effective strategy for reducing FFA levels and producing oxidatively stable, astaxanthin-rich acylglyceride squid oil with DHA retained at the nutritionally favored sn-2 position.
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spelling doaj-art-09b961b175694fb4a73a21a9f3ec5f472025-01-24T13:39:30ZengMDPI AGMarine Drugs1660-33972025-01-012312110.3390/md23010021Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional ApplicationsAsavari Joshi0Brendan Holland1Moninder Sachar2Colin J. Barrow3ARC Industrial Transformation Training Centre for Green Chemistry in Manufacturing, Deakin University, Waurn Ponds, Geelong, VIC 3216, AustraliaCentre for Sustainable Bioproducts, Deakin University, Waurn Ponds, Geelong, VIC 3216, AustraliaAustralian Omega Oils Pty Ltd., North Geelong, Geelong, VIC, 3215, AustraliaARC Industrial Transformation Training Centre for Green Chemistry in Manufacturing, Deakin University, Waurn Ponds, Geelong, VIC 3216, AustraliaSquid viscera, a byproduct of squid processing, contains oil rich in omega-3 fatty acids (up to 10% by mass) and the antioxidant astaxanthin. However, its high free fatty acid (FFA) content compromises stability. To address this, pilot-scale (200 L) enzymatic re-esterification of squid oil using immobilized lipase (Lipozyme RMIM) was demonstrated, resulting in high acylglyceride yields. The processed oil was analyzed for oxidation kinetics and thermodynamics using Rancimat, fatty acid composition using GC, omega-3 fatty acid positional distribution in the acylglyceride product using <sup>13</sup>C NMR, and astaxanthin content. Lipase treatment reduced FFA levels from 44% to 4% and increased acylglycerides to 93% in squid oil. This reduction in FFA was accompanied by significantly increased stability (0.06 to 18.9 h by Rancimat). The treated oil showed no loss in astaxanthin (194.1 µg/g) or omega-3 fatty acids, including docosahexaenoic acid (DHA). DHA remaining predominantly at sn-2 indicated that the naturally occurring positional distribution of this omega-3 FFA was retained in the product. Lipase treatment significantly enhanced oxidative stability, evidenced by improved thermodynamic parameters (E<sub>a</sub> 94.15 kJ/mol, ΔH 91.09 kJ/mol, ΔS −12.6 J/mol K) and extended shelf life (IP<sub>25</sub> 74.42 days) compared to starting squid oil and commercial fish/squid oils lacking astaxanthin. Thus, lipase treatment offers an effective strategy for reducing FFA levels and producing oxidatively stable, astaxanthin-rich acylglyceride squid oil with DHA retained at the nutritionally favored sn-2 position.https://www.mdpi.com/1660-3397/23/1/21enzyme-processed squid oilrancimatlipid oxidation kineticsastaxanthin
spellingShingle Asavari Joshi
Brendan Holland
Moninder Sachar
Colin J. Barrow
Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional Applications
Marine Drugs
enzyme-processed squid oil
rancimat
lipid oxidation kinetics
astaxanthin
title Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional Applications
title_full Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional Applications
title_fullStr Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional Applications
title_full_unstemmed Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional Applications
title_short Pilot-Scale Enzymatic Conversion of Low Stability, High Free Fatty, Squid Oil to an Oxidatively Stable Astaxanthin-Rich Acylglyceride Oil Suitable for Nutritional Applications
title_sort pilot scale enzymatic conversion of low stability high free fatty squid oil to an oxidatively stable astaxanthin rich acylglyceride oil suitable for nutritional applications
topic enzyme-processed squid oil
rancimat
lipid oxidation kinetics
astaxanthin
url https://www.mdpi.com/1660-3397/23/1/21
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