Mohd Asraf Mohd Zainudin
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Preferred name
Mohd Asraf Mohd Zainudin
Official Name
Mohd Asraf, Mohd Zainudin
Alternative Name
Mohd Zainudin, Mohd Asraf
Zainudin, M. A.M.
Main Affiliation
Scopus Author ID
55539687700
Researcher ID
AAV-4476-2020

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Combination of light and oxygen accelerates formation of covalent protein-polyphenol bonding during chill storage of meat added 4-methyl catechol

2021-01-01 , Mohd Asraf Mohd Zainudin , Jongberg S. , Lund M.N.

Plant polyphenols applied as natural antioxidant ingredients, are known to bind to cysteine residues on meat proteins. The aim of this study was to examine the effect of light exposure on the formation of cysteine-phenol adduct in meat added 4-methylcatechol (4MC), a model polyphenol, during storage through quantitative LC-MS/MS-based analysis. Cysteine-4-methylcatechol adduct (Cys-4MC) formation in meat added 1500 ppm 4-MC increased significantly (by 50%) when stored under light in oxygen at 4 °C for 7 days as compared to storage in the dark. This was reflected by a significant decrease in thiol concentrations in the same sample. Gel electrophoresis showed loss in myosin heavy chain (MHC), and a resulting increase in cross-linked MHC (CL-MHC) and larger protein polymers in samples added 4MC. Protein blots stained with nitroblue tetrazolium (NBT) showed intensive protein-polyphenol binding in the meat samples added 4MC, but no major differences between storage conditions.

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Pharmacognostic Evaluation of Zingiber Officinale and Curcuma Longa from Perlis for Therapeutic Discovery

2023-01-01 , Jamil A. , San L.P. , Nik Muhammad Azhar Nik Daud , Mohd Asraf Mohd Zainudin , Mohd Qalani Che Kasim , Muhammad Izzat Ridzuan , Khairuddin N.H. , Amirul Ridzuan Abu Bakar

The medicinal properties of a plant are sought after for its potential therapeutic properties. Through its phytochemicals, numerous biological activities have been reported scientifically and were developed as an active pharmaceutical ingredient for biological products. Hence, this study evaluated the locally produced Zingiber officinale and Curcuma longa obtained from Padang Besar, Perlis, for their pharmacognostic properties. Quality control assessments were conducted to determine the cleanliness of the raw materials before proceeding with the pharmacognostic evaluation. The extracts for both plants were prepared through ultrasonic-assisted extraction (UAE) and maceration using methanol, ethanol, and distilled water. The phenolic compounds, flavonoids, and protein for each extract were investigated. The total phenolic compounds revealed that the combination of UAE and methanol had the highest value for both plant samples. On the other hand, the total flavonoid content suggests that UAE in ethanol solvent was the best approach to extract flavonoids for both plants. On the contrary, maceration techniques extracted the highest protein content for both plants. The biological testing for therapeutic evaluation based on the 2,2-diphenyl-1-picrylhydrazyl scavenging assay unraveled the methanol UAE was the potent extract for Z. officinale and C. longa, with half maximal inhibitory concentration, IC50 values of 0.39 and 0.32 mg/mL, respectively. Altogether, the findings obtained from these studies showed that Z. officinale and C. longa from Perlis showed good quality conditions, high content of phytochemicals, and potent antioxidant properties suitable for further herbal drug development studies.

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Profiling of Bioactive Compounds and Bioactivity of the Kenaf (Hibiscus Cannabinus L.) Leaf Extract

2023-01-01 , Shukri S.Z.M. , Nik Muhammad Azhar Nik Daud , Amirul Ridzuan Abu Bakar , Arsad S.S. , Mohd Asraf Mohd Zainudin

The current research examines the impact of different solvents and maturity stages of the kenaf leaf (Hibiscus Cannabinus L. var. Everglade 51) on the bioactive compound and bioactivity, which specifically focused on antioxidant and antimicrobial properties. The kenaf’s leaf powder was extracted sequentially using hexane, acetone, and methanol. The total phenolic compound (TPC), flavonoid content (TFC), and free-radical scavenging activity using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay were measured using UV–Vis spectrometry. The antibacterial activity of the extract was determined using the disc diffusion method on both Gram-positive and -negative bacteria. Results show that the methanol extracts had a significant (p < 0.05) quantity of TPC and TFC compared to other extracts. Results showed that the antioxidant compound amount measured as TPC and TFC in extract increased from shoot stages into mature leaves by 11% and 24%, respectively. As expected, methanolic extract of mature leaf exerts the highest TPC and TFC value compared to that of other solvents. This also reflects the antioxidant activity among the different extract where methanolic extract showed the highest antioxidant activity with value 60.48 ± 0.24% of radical scavenging activity. Meanwhile, only the methanolic and acetone extracts demonstrated a significant (p < 0.05) inhibitory zone against Gram-negative microorganisms. Overall, mature kenaf leaf extracted with methanol and acetone solvents showed a particularly high in terms of antioxidant capacity and antimicrobial characteristics. Mature kenaf leaf was recommended for food product development due to their strong antioxidant activity and ability to inhibit Gram-negative bacteria.

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Effect of Different Drying Process on the Protein-Thiol Content and the Physicochemical Properties of Water-Extracted Rice Bran Powder

2023-06-09 , Kasman N.A.S. , Mohd Sharizan Md Sarip , Mohd Asraf Mohd Zainudin

The effect of drying process of the water extracted rice bran powder on the protein-thiol and physicochemical properties was investigated. The rice bran extracted was prepared with water as solvent at high temperature and pressure using the autoclave equipment (121 °C, 15 psi, and 20 min) before undergone drying method using either spray dryer (BṺCHI Mini Spray Dryer B-290, LABOGENE, Denmark) or freeze dryer (CoolSafe 4-15L Freeze Dryers, LABOGENE, Denmark). The water-extracted rice bran powder (WRBP) yield, protein-free thiol compound, physical and functional properties were analyzed. The protein-thiol concentration was quantified using the 5,5 dithiobis (2-nitrobenzoic acid (DTNB) method while protein concentration was directly measured at 280 nm by UV-Vis Spectrophotometer. This was followed by physical properties (water solubility) and functional properties (foaming capacity and stability, water and oil absorption capacity) analysis. The powder yield of freeze-dried WRBP (7.69 ±0.29%) was significantly (p<0.05) higher than spray-dried WRBP (4.43 ±0.24%). The protein concentration of spray-dried WRBP (4.02 ±0.36 mg/mL) was higher than freeze-dried WRBP (3.91 ±0.75 mg/mL). Meanwhile, freeze-dried WRBP (1.22 ±0.36 nmol thiol/mg protein) had a higher thiol concentration than spray dried WRBP (1.18 ± 0.30 nmol thiol/mg protein). However, both results were not significantly different (p>0.05) between the drying method. Spray-dried WRBP had significantly (p<0.05) higher solubility in water compared to that of freeze-dried WRBP with values 1.22 ± 0.21% and 0.63 ± 0.34%, respectively. Freeze-dried WRBP had higher water and oil absorption capacity. There was no significant difference (p>0.05) in foaming capacity and stability for both drying treatments. In conclusion, the drying method for WRBP production could significantly affect the WRBP physicochemical properties.

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Prediction of phase equilibria in ternary diagram for system consist of Hot Compressed Water (HCW) with crude palm oil (CPO) and others minor component using thermodynamic model

2024-05-10 , Mohd Sharizan Md Sarip , Nik Muhammad Azhar Nik Daud , Mohd Asraf Mohd Zainudin , Idham Z. , Adilah Anuar , Mohd Aminudin Jamlos , Amirul Ridzuan Abu Bakar

Knowledge on phase equilibria for the separation process are important. It helps to improve the extraction efficiency through parameter optimization. Nowadays, hot compressed water extraction (HCWE) is getting the interest for the crude palm oil (CPO) extraction. Therefore, the phase equilibria of system consist of Hot compressed water (HCW) and CPO component are crucial. In this study, prediction of phase equilibria in ternary diagram for system consist of HCW with CPO and others minor component was conducted using thermodynamic model. The prediction was conducted using modified UNIFAC. CPO and other minor components namely palmitic acid which represent FFA, β-carotene, α-tocopherol, α-tocotrienol and α-tocotrieno was totally insoluble in HCW. The solubility of HCW in CPO was effect by the temperature and concentration of palmitic acid, β-carotene and α-tocopherol. However, the effect of these minor component concentration was inrrelevant since the concentration of these component was lower in the CPO for less than 1%. The solubility of HCW in CPO need to be monitored to avoid the hydrolysis which can deteriorate the CPO and degrade its quality.

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Quantitation of Protein Cysteine-Phenol Adducts in Minced Beef Containing 4-Methyl Catechol

2020-02-26 , Arsad S.S. , Mohd Asraf Mohd Zainudin , De Gobba C. , Jongberg S. , Larsen F.H. , Lametsch R. , Andersen M.L. , Lund M.N.

Thiol groups of cysteine (Cys) residues in proteins react with quinones, oxidation products of polyphenols, to form protein-polyphenol adducts. The aim of the present work was to quantify the amount of adduct formed between Cys residues and 4-methylcatechol (4MC) in minced beef. A Cys-4MC adduct standard was electrochemically synthesized and characterized by liquid chromatography-mass spectrometry (LC-MS) as well as NMR spectroscopy. Cys-4MC adducts were quantified after acidic hydrolysis of myofibrillar protein isolates (MPIs) and LC-MS/MS analysis of meat containing either 500 or 1500 ppm 4MC and stored at 4 °C for 7 days under a nitrogen or oxygen atmosphere. The concentrations of Cys-4MC were found to be 2.2 ± 0.3 nmol/mg MPI and 8.1 ± 0.9 nmol/mg MPI in meat containing 500 and 1500 ppm 4MC, respectively, and stored for 7 days under oxygen. The formation of the Cys-4MC adduct resulted in protein thiol loss, and ca. 62% of the thiol loss was estimated to account for the formation of the Cys-4MC adduct for meat containing 1500 ppm 4MC. Furthermore, protein polymerization increased in samples containing 4MC as evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the polymerization was found to originate from protein-polyphenol interactions as evaluated by a blotting assay with staining by nitroblue tetrazolium.

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