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Effects of sonication on the extraction of free-amino acids from moromi and application to the laboratory scale rapid fermentation of soy sauce

Goh KM, Lai OM, Abas F, Tan CP

Food Chem, 2017 Jan 15;215:200-8.
PMID: 27542468 DOI: 10.1016/j.foodchem.2016.07.146

Soy sauce fermentation was simulated in a laboratory and subjected to 10min of sonication. A full factorial design, including different cycles, probe size, and amplitude was used. The composition of 17 free-amino acids (FAAs) was determined by the AccQ-Tag method with fluorescent detection. Main effect plots showed total FAAs extraction was favoured under continuous sonication at 100% amplitude using a 14mm diameter transducer probe, reaching 1214.2±64.3mg/100ml of total FAAs. Moreover, after 7days of fermentation, sonication treatment caused significantly higher levels (p<0.05) of glutamic acids (343.0±22.09mg/100g), total FAAs (1720.0±70.6mg/100g), and essential FAAs (776.3±7.0mg/100g) 3days sooner than the control. Meanwhile, enzymatic and microbial behaviours remained undisturbed. Collectively, the sonication to moromi resulted in maturation 57% faster than the untreated control.
Fatty acid preference of mycelium-bound lipase from a locally isolated strain of Geotrichum candidum

Loo JL, Lai OM, Long K, Ghazali HM

World J Microbiol Biotechnol, 2007 Dec;23(12):1771-8.
PMID: 27517833 DOI: 10.1007/s11274-007-9427-2

Mycelium-bound lipase (MBL) was prepared using a strain of Geotrichum candidum isolated from local soil. At the time of maximum lipase activity (54 h), the mycelia to which the lipase was bound were harvested by filtration and centrifugation. Dry MBL was prepared by lyophilizing the mycelia obtained. The yield of MBL was 3.66 g/l with a protein content of 44.11 mg/g. The lipase activity and specific lipase activity were 22.59 and 510 U/g protein, respectively. The moisture content of the MBL was 3.85%. The activity of free (extracellular) lipase in the culture supernatant (after removal of mycelia) was less than 0.2 U/ml. The MBL showed selectivity for oleic acid over palmitic acid during hydrolysis of palm olein, indicating that the lipase from G. candidum displayed high substrate selectivity for unsaturated fatty acid containing a cis-9 double bond, even in crude form. This unique specificity of MBL could be a direct, simple and inexpensive way in the fats and oil industry for the selective hydrolysis or transesterification of cis-9 fatty acid residues in natural triacylglycerols.
Fingerprinting of Phospholipid Molecular Species from Human Milk and Infant Formula Using HILIC-ESI-IT-TOF-MS and Discriminatory Analysis by Principal Component Analysis

Jiang C, Ma B, Song S, Lai OM, Cheong LZ

J Agric Food Chem, 2018 Jul 11;66(27):7131-7138.
PMID: 29902005 DOI: 10.1021/acs.jafc.8b01393

Phospholipid composition in the milk fat globule membrane (MFGM) fluctuates during the entire lactation period in order to suit the growing needs of newborn infants. The present study elucidated and relatively quantified phospholipid molecular species extracted from human milk (HM), mature human milk (MHM), and infant formulas (with or without MFGM supplementation) using hydrophilic liquid chromatography-electrospray ionization-ion trap-time of flight-mass spectrometry (HILIC-ESI-IT-TOF-MS) system. Principal component analysis was used to clarify the differences between phospholipid composition in HM, MHM, and infant formulas. HM and MHM contained high concentrations of sphingomyeline (HM: 107.61 μg/mL, MHM: 227.18 μg/mL), phosphatidylcholine (HM: 59.96 μg/mL, MHM: 50.77 μg/mL), and phosphatidylethanolamine (PE) (HM: 25.24 μg/mL, MHM: 31.76 μg/mL). Significant concentrations (<300 ng/mL) of arachidonic, eicosapentanoic, and docosahexanoic acids were found to esterify to PE in HM and MHM. Meanwhile, all infant formulas were found to contain high concentrations of phosphatidic acids indicating the possibility of degradation of the fortified MFGM either during processing or storage of the infant formulas.
Biomimetic self-assembly of lipase-zeolitic imidazolate frameworks with enhanced biosensing of protox inhibiting herbicides

Cheng C, Shen C, Lai OM, Tan CP, Cheong LZ

Anal Methods, 2021 Nov 04;13(42):4974-4984.
PMID: 34661208 DOI: 10.1039/d1ay01307f

Protox inhibiting herbicides such as nitrofen have detrimental effects on the environment and human health. The current work aims to fabricate a Candida rugosa lipase (CRL)-based electrochemical sensor for rapid and sensitive detection of protox inhibiting herbicides (nitrofen). We proposed the use of poly(vinylpyrrolidone) (PVP) and amino-acids to promote accumulation of Zn2+ ions at the surfaces of Candida rugosa lipase (CRL) and subsequently induce self-assembly of a CRL-zeolitic imidazolate framework (ZIF) structure. This process can be easily and rapidly achieved via a one-pot facile self-assembly method. Steady-state fluorescence spectroscopy indicated that CRL has undergone a conformational change following encapsulation within the ZIF structure. This conformational change is beneficial as the prepared PVP/Glu/CRL@ZIF-8 exhibited enhanced catalytic activity (207% of native CRL), and higher substrate affinity (lower Km than native CRL) and showed high stability under harsh denaturing conditions. PVP/Glu/CRL@ZIF-8 was finally used for electrochemical biosensing of nitrofen. The fabricated biosensor has a wide linear detection range (0-100 μM), a lower limit of detection and a good recovery rate.
Fulltext Changes in 3-MCPD esters, glycidyl esters, bioactive compounds and oxidation indexes during kenaf seed oil refining

Chew SC, Tan CP, Lai OM, Nyam KL

Food Sci Biotechnol, 2018 Jun;27(3):905-914.
PMID: 30263818 DOI: 10.1007/s10068-017-0295-8

An optimized refining process for kenaf seed oil was conducted. The 3-monochloro-1,2-propanediol (3-MCPD) contents, triacylglycerol composition, fatty acids composition, bioactive compounds, phosphorus contents, and oxidation indexes of the kenaf seed oil during each stage of the refining process were determined. The results showed that there was no detected 3-MCPD ester in kenaf seed oil throughout the refining process. Deodorization had slightly increased the 2-MCPD ester (9.0 μg/kg) and glycidyl ester (54.8 μg/kg). Oleic (36.53%) and linoleic acids (36.52%) were presented in the largest amount in the refined kenaf seed oil, and triacylglycerols contributed to 99.96% in the oil. There was a removal of 31.6% of phytosterol content and 17.1% of tocopherol and tocotrienol contents in kenaf seed oil after refining. The refining process was totally removed the hydroperoxides, 93% of free fatty acids and 98.8% of phosphorus content in kenaf seed oil.
Fulltext Production of a solvent, detergent, and thermotolerant lipase by a newly isolated Acinetobacter sp. in submerged and solid-state fermentations

Khoramnia A, Ebrahimpour A, Beh BK, Lai OM

J Biomed Biotechnol, 2011;2011:702179.
PMID: 21960739 DOI: 10.1155/2011/702179

The lipase production ability of a newly isolated Acinetobacter sp. in submerged (SmF) and solid-state (SSF) fermentations was evaluated. The results demonstrated this strain as one of the rare bacterium, which is able to grow and produce lipase in SSF even more than SmF. Coconut oil cake as a cheap agroindustrial residue was employed as the solid substrate. The lipase production was optimized in both media using artificial neural network. Multilayer normal and full feed forward backpropagation networks were selected to build predictive models to optimize the culture parameters for lipase production in SmF and SSF systems, respectively. The produced models for both systems showed high predictive accuracy where the obtained conditions were close together. The produced enzyme was characterized as a thermotolerant lipase, although the organism was mesophile. The optimum temperature for the enzyme activity was 45°C where 63% of its activity remained at 70°C after 2 h. This lipase remained active after 24 h in a broad range of pH (6-11). The lipase demonstrated strong solvent and detergent tolerance potentials. Therefore, this inexpensive lipase production for such a potent and industrially valuable lipase is promising and of considerable commercial interest for biotechnological applications.
Health benefits, enzymatic production, and application of medium- and long-chain triacylglycerol (MLCT) in food industries: a review

Lee YY, Tang TK, Lai OM

J Food Sci, 2012 Aug;77(8):R137-44.
PMID: 22748075 DOI: 10.1111/j.1750-3841.2012.02793.x

Medium- and long-chain triacylglycerol (MLCT) is a modified lipid containing medium- chain (C6-C12) and long-chain fatty acids (C14-C24) in the same triacylglycerol (TAG) molecule. It can be produced either through enzymatic (with 1,3 specific or nonspecific enzyme) or chemical methods. The specialty of this structured lipid is that it is metabolized differently compared to conventional fats and oils, which can lead to a reduction of fat accumulation in the body. Therefore, it can be used for obesity management. It also contains nutritional properties that can be used to treat metabolic problems. This review will discuss on the health benefits of MLCT, its production methods especially via enzymatic processes and its applications in food industries.
Open-label, single-arm, single-center clinical study on the effectiveness and safety of a moisturizer containing tocotrienol-rich composition in children with mild to moderate atopic dermatitis

How KN, Chang HW, Lai OM

J Cosmet Dermatol, 2023 Oct;22(10):2746-2754.
PMID: 37143441 DOI: 10.1111/jocd.15793

BACKGROUND: Little is known about antioxidant efficacy of topical vitamin E on atopic dermatitis (AD) due to lack of controlled clinical studies.
AIM: The study evaluates the effectiveness and safety of a topical moisturizer containing tocotrienol-rich composition over 12 weeks on patients aged between 1 month and 12 years with mild to moderate AD.
METHODS: We conducted a 12 weeks, prospective, open-label clinical study on the effect of tocotrienol as an adjunct to conventional treatment. This study was approved by the Ethics Committee for Research Involving Human Subject. JKEUPM-2019-274 (NMMR-19-1588-49234).
RESULTS: Thirty AD patients with a mean age of 2.77 ± 3.05 were enrolled in the study. At week-12, significant reduction of investigator global assessment (63.4%), Patient-Oriented Scoring Atopic Dermatitis Index (PO-SCORAD) (65%), and SCORAD (52.3%) was noted (p