Faculty Publications
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Item A new strategy to refine crude Indian sardine oil(Japan Oil Chemists Society yukagaku@jocs-office.or.jp, 2017) Charanyaa, S.; Belur, B.D.; Iyyaswami, R.Current work aims to develop a refining process for removing phospholipids, free fatty acids (FFA), and metal ions without affecting n-3 polyunsaturated fatty acid (n-3 PUFA) esters present in the crude Indian sardine oil. Sardine oil was subjected to degumming with various acids (orthophosphoric acid, acetic acid, and lactic acid), conventional and membrane assisted deacidification using various solvents (methanol, ethanol, propanol and butanol) and bleaching with bleaching agents (GAC, activated earth and bentonite) and all the process parameters were further optimized. Degumming with 5%(w/w) ortho phosphoric acid, two stage solvent extraction with methanol at 1:1 (w/w) in each stage and bleaching with 3% (w/w) activated charcoal loading, at 80ºC for 10 minutes resulted in the reduction of phospholipid content to 5.66 ppm from 612.66 ppm, FFA to 0.56% from 5.64% with the complete removal of iron and mercury. Under these conditions, the obtained bleached oil showed an enhancement of n-3 PUFA from 16.39% (11.19 Eicosapentaenoic acid (EPA) + 5.20 Docosahexaenoic acid (DHA)) to 17.91% (11.81 EPA + 6.1 DHA). Replacing conventional solvent extraction with membrane deacidification using microporous, hydrophobic polytetrafluoroethylene membrane (PTFE), resulted in a lesser solvent residue (0.25% (w/w)) in the deacidified oil. In view of lack of reports on refining of n-3 PUFA rich marine oils without concomitant loss of n-3 PUFA, this report is significant. © 2017 by Japan Oil Chemists’ Society.Item Lipase mediated synthesis of rutin fatty ester: Study of its process parameters and solvent polarity(Elsevier Ltd, 2017) Chandrasekar, C.; Belur, P.D.; Iyyaswami, R.Lipophilization of antioxidants is recognized as an effective strategy to enhance solubility and thus effectiveness in lipid based food. In this study, an effort was made to optimize rutin fatty ester synthesis in two different solvent systems to understand the influence of reaction system hydrophobicity on the optimum conditions using immobilised Candida antartica lipase. Under unoptimized conditions, 52.14% and 13.02% conversion was achieved in acetone and tert-butanol solvent systems, respectively. Among all the process parameters, water activity of the system was found to show highest influence on the conversion in each reaction system. In the presence of molecular sieves, the ester production increased to 62.9% in tert-butanol system, unlike acetone system. Under optimal conditions, conversion increased to 60.74% and 65.73% in acetone and tert-butanol system, respectively. This study shows, maintaining optimal water activity is crucial in reaction systems having polar solvents compared to more non-polar solvents. © 2017 Elsevier LtdItem Effectiveness of rutin and its lipophilic ester in improving oxidative stability of sardine oil containing trace water(Blackwell Publishing Ltd customerservices@oxonblackwellpublishing.com, 2018) Chandrasekar, C.; Belur, P.D.; Iyyaswami, R.Poor oxidative stability exhibited by n-3 polyunsaturated fatty acid rich sardine oil is a major challenge for its utilisation in industry. Considering the fact that water is always present in bulk oil in trace amounts during storage, an effort was made to understand and compare the effectiveness of rutin and its corresponding lipophilic ester in enhancing oxidative stability of refined sardine oil containing trace water (0.16% w/w). Peroxide value, conjugated diene value, p-anisidine value and thiobarbituric acid reactive substances (TBARS) value were determined during 20 days storage. Rutin fatty ester showed 50% reduction in primary oxidation and 42.46% reduction in secondary oxidation, whereas rutin showed 20.6% and 20.43% reduction in primary and secondary oxidation, respectively, by the end of 20 days storage. Thus, it is clearly established that rutin fatty ester is more effective than hydrophilic rutin in sardine oil containing trace water, which contradicts the polar paradox theory. © 2017 Institute of Food Science and TechnologyItem Enhancement of n-3 polyunsaturated fatty acid glycerides in Sardine oil by a bioimprinted cross-linked Candida rugosa lipase(Elsevier Inc. usjcs@elsevier.com, 2018) Sampath, C.; Belur, P.D.; Iyyaswami, R.Considering the advantages of bioimprinting and carrier free immobilization, cross-linked enzyme aggregates (CLEA) were prepared by using bioimprinted Candida rugosa lipase (CRL) with Bovine serum albumin (BSA), Polyethyleneimine and glutaraldehyde. Effect of various factors such as CRL-Oleic acid ratio, CRL-BSA ratio, CRL- Polyethyleneimine ratio, glutaraldehyde loading, cross-linking time etc., on lipase activity recovery and aggregate yield were studied and optimized. This immobilized lipase (CRL-CLEA) was used for the selective hydrolysis of ester linkages of non-PUFA glycerides, with an aim to concentrate EPA and DHA glycerides in the Sardine oil. Imprinting with oleic acid in the presence of ethanol and Tween 60, and further immobilization with co-aggregates and cross-linking agent showed 10.4 times higher degree of hydrolysis compared to free enzyme. As result, 2.83-fold increase of n-3 PUFA content in deacidified oil was obtained by using CRL-CLEA. The resultant oil had negligible di- and triglycerides content, proving higher efficiency in hydrolysing ester bonds of fatty acids, other than n-3 PUFA. Reusability studies showed CRL-CLEA could be reused up to 5 runs without a substantial reduction in its performance. Improvement in degree of hydrolysis, thermostability, efficiency of hydrolysis and reusability were achieved due to bioimprinting and subsequent immobilization of CRL in the form of CLEA. © 2017 Elsevier Inc.Item Probing the synergistic effects of rutin and rutin ester on the oxidative stability of sardine oil(Springer, 2022) Chandrasekar, V.; Arunachalam, S.S.; Hari, H.; Shinkar, A.; Belur, P.D.; Iyyaswami, R.Multicomponent antioxidant mixture is proved to be highly effective in imparting oxidative stability to the edible oil. It is believed that the high efficacy of those mixtures is due to the synergistic effect exhibited by two or more components. The current study aims to analyse the synergistic effect of a flavonoid and its corresponding ester in improving the oxidative stability of n-3 PUFA rich sardine oil. The oxidative stability of rutin, esterified rutin and their combinations at three different concentrations was studied in sardine oil stored at 37 ºC for 12 days in contact with air under darkness. The combination of rutin and rutin ester showed maximum reduction of 54.2% in oxidation at 100 mg/kg and 150 mg/kg. Perhaps this is the first report on the synergistic effect of a flavonoid and its lipophilized ester for improving the oxidative stability of n-3 PUFA rich oil. © 2022, Association of Food Scientists & Technologists (India).