Mohammed Hamk - Academia.edu (original) (raw)

Papers by Mohammed Hamk

Preparative Biochemistry & Biotechnology, May 26, 2022

Kurdistan journal of applied research, Jun 11, 2018

Effect of transglutaminase, Maillard reaction induced crosslinking and combination of transglutam... more Effect of transglutaminase, Maillard reaction induced crosslinking and combination of transglutaminase and Maillard reaction induced crosslinking between whey proteins and caseins in milk on calcium milk gel properties were investigated. Treatment of milk with transglutaminase, Maillard reaction and transglutaminase + Maillard reaction cause to the appearance of new high MW protein bands. Water holding capacity , gel strength and sensory scores of gel samples increased and spontaneous whey separation decreased in calcium-induced milk gel made from transglutaminase and combination of transglutaminase and Maillard reaction treated milk compare with calcium-induced milk gel made from untreated milk alone.

Gida the Journal of Food, Apr 15, 2023

Typha domingensis pollen is obtained from staminate flowers of plant that is edible. In this stud... more Typha domingensis pollen is obtained from staminate flowers of plant that is edible. In this study, bioactive compounds from pollen were extracted using ethanol and methanol with conventional method. Further ultrasonication was applied to the samples to improve extraction efficiency. The extraction yield was higher with ethanol (26.3±0.14%) than with methanol (25.4±0.3%) and applying ultrasonication increased the yields significantly (P <0.05). Total phenolic compounds in ethanol and methanol extracts were determined as 9.83±0.48 and 9.71±0.55 mg GAE/g dry matter with the conventional method, and 11.76±0.64 and 12.74±0.37 mg GAE/g dry matter after ultrasonication, respectively. The flavonoid content with ethanol extraction was significantly higher than with methanol in both conventional and ultrasonication methods (P <0.05). Antioxidant activities using DPPH, ABTS, CUPRAC, and FRAP tests, were determined, and enhanced antioxidant capacities were observed after ultrasonication. The bioactive compounds were qualitatively analyzed using UV-VIS spectroscopy and FTIR which confirmed the presence of polyphenols.

Biomass Conversion and Biorefinery

In this study, extracellular biosynthesis of zinc oxide nanoparticles (ZnO NPs) by using the supe... more In this study, extracellular biosynthesis of zinc oxide nanoparticles (ZnO NPs) by using the supernatant of Bacillus subtilis ZBP4 after cultivation in nutrient broth at 33 C for 24 h was investigated. Zinc sulfate heptahydrate was used as the precursor, and the reactions were performed at 33 C for 72 h. The effects of pH 5-9 and precursor concentration (2-10 mM) were determined and the optima were found to be pH 7.5 and 8 mM ZnSO 4 Á7H 2 O, respectively. The nanoparticles were characterized by UV-VIS spectroscopy, FESEM, TEM, EDS, XRD, FTIR and zeta potential measurement. ZnO NPs appeared to be irregular spherical structures with a size range of 22-59 nm, as confirmed by FESEM and TEM. Energy-dispersive spectroscopy analysis validated the formation of ZnO NPs. X-ray diffraction analysis revealed the crystalline structure of the ZnO NPs, and they were determined to have a zeta potential of À19.0 ± 4.3 mV and a bandgap of 3.36 eV. Antibacterial activity experiments showed that ZnO NPs are effective against a broad spectrum of Gram-positive and Gram-negative food pathogens. This study provides evidence for a safe and effective method for synthesizing ZnO NPs and demonstrates their effectiveness against pathogenic bacteria.

The release of azo dyes from industrial effluents is a serious environmental concern because of t... more The release of azo dyes from industrial effluents is a serious environmental concern because of their colors and unfavorable impact on water quality. One method for combating their release is biological degradation. In this study, the potential of a newly isolated Bacillus sp. SBT8 strain for the decolorization and degradation of Reactive Orange 13 (RO13) was investigated. Conditions favorable for decolorization including temperature (25-42 °C), pH (5.0-10.0), culture age (0-24 h), and dye concentration (25-200 mg/L) were determined. Adding RO13 during the mid-exponential phase (8 h following inoculation) accelerated the rate of decolorization. Efficient decolorization was observed in broad pH (6.0-10.0) and temperature (25-35 °C) ranges with the optima at pH 7.0 and 33 °C, respectively. A complete decolorization was observed at pH 7.0, 35 °C, and 25 mg/L dye concentration in 48 h. Increased dye concentrations (over 100 mg/L) had inhibitory effects on the degradation of dye as measured after 48 h: 25, 50, and 100 mg/L dye concentrations were decolorized by 100, 83.58 ± 3.07, and 42.68 ± 3.02%, respectively. Decolorization and biodegradation were confirmed by UV-VIS spectroscopy, FTIR, and LC-MS. The analysis with FTIR affirmed the cleavage of the azo bond and the formation of novel products. The metabolites were determined by LC-MS analyses and a possible biodegradation pathway was proposed. Phytotoxicity was tested on Lens culinaris and the non-toxic nature of the metabolites was revealed. This study provides insights into the potentiality of Bacillus sp. SBT8 isolate on the decolorization and biodegradation of azo dyes.

Biomass Conversion and Biorefinery

Kurdistan Journal of Applied Research, 2018

Effect of transglutaminase, Maillard reaction induced crosslinking and the combination of transgl... more Effect of transglutaminase, Maillard reaction induced crosslinking and the combination of transglutaminase and Maillard reaction induced crosslinking between whey proteins and caseins in milk on calcium milk gel properties were investigated. Treatment of milk with transglutaminase, Maillard reaction, and transglutaminase + Maillard reaction cause to the appearance of new high MW protein bands. Water holding capacity, gel strength and sensory scores of gel samples increased and spontaneous whey separation decreased in calcium-induced milk gel made from transglutaminase and combination of transglutaminase and Maillard reaction treated milk compare with calcium-induced milk gel made from untreated milk alone.

Journal of Zankoy Sulaimani - Part A

Preparative Biochemistry & Biotechnology, May 26, 2022

Kurdistan journal of applied research, Jun 11, 2018

Effect of transglutaminase, Maillard reaction induced crosslinking and combination of transglutam... more Effect of transglutaminase, Maillard reaction induced crosslinking and combination of transglutaminase and Maillard reaction induced crosslinking between whey proteins and caseins in milk on calcium milk gel properties were investigated. Treatment of milk with transglutaminase, Maillard reaction and transglutaminase + Maillard reaction cause to the appearance of new high MW protein bands. Water holding capacity , gel strength and sensory scores of gel samples increased and spontaneous whey separation decreased in calcium-induced milk gel made from transglutaminase and combination of transglutaminase and Maillard reaction treated milk compare with calcium-induced milk gel made from untreated milk alone.

Gida the Journal of Food, Apr 15, 2023

Typha domingensis pollen is obtained from staminate flowers of plant that is edible. In this stud... more Typha domingensis pollen is obtained from staminate flowers of plant that is edible. In this study, bioactive compounds from pollen were extracted using ethanol and methanol with conventional method. Further ultrasonication was applied to the samples to improve extraction efficiency. The extraction yield was higher with ethanol (26.3±0.14%) than with methanol (25.4±0.3%) and applying ultrasonication increased the yields significantly (P <0.05). Total phenolic compounds in ethanol and methanol extracts were determined as 9.83±0.48 and 9.71±0.55 mg GAE/g dry matter with the conventional method, and 11.76±0.64 and 12.74±0.37 mg GAE/g dry matter after ultrasonication, respectively. The flavonoid content with ethanol extraction was significantly higher than with methanol in both conventional and ultrasonication methods (P <0.05). Antioxidant activities using DPPH, ABTS, CUPRAC, and FRAP tests, were determined, and enhanced antioxidant capacities were observed after ultrasonication. The bioactive compounds were qualitatively analyzed using UV-VIS spectroscopy and FTIR which confirmed the presence of polyphenols.

Biomass Conversion and Biorefinery

In this study, extracellular biosynthesis of zinc oxide nanoparticles (ZnO NPs) by using the supe... more In this study, extracellular biosynthesis of zinc oxide nanoparticles (ZnO NPs) by using the supernatant of Bacillus subtilis ZBP4 after cultivation in nutrient broth at 33 C for 24 h was investigated. Zinc sulfate heptahydrate was used as the precursor, and the reactions were performed at 33 C for 72 h. The effects of pH 5-9 and precursor concentration (2-10 mM) were determined and the optima were found to be pH 7.5 and 8 mM ZnSO 4 Á7H 2 O, respectively. The nanoparticles were characterized by UV-VIS spectroscopy, FESEM, TEM, EDS, XRD, FTIR and zeta potential measurement. ZnO NPs appeared to be irregular spherical structures with a size range of 22-59 nm, as confirmed by FESEM and TEM. Energy-dispersive spectroscopy analysis validated the formation of ZnO NPs. X-ray diffraction analysis revealed the crystalline structure of the ZnO NPs, and they were determined to have a zeta potential of À19.0 ± 4.3 mV and a bandgap of 3.36 eV. Antibacterial activity experiments showed that ZnO NPs are effective against a broad spectrum of Gram-positive and Gram-negative food pathogens. This study provides evidence for a safe and effective method for synthesizing ZnO NPs and demonstrates their effectiveness against pathogenic bacteria.

The release of azo dyes from industrial effluents is a serious environmental concern because of t... more The release of azo dyes from industrial effluents is a serious environmental concern because of their colors and unfavorable impact on water quality. One method for combating their release is biological degradation. In this study, the potential of a newly isolated Bacillus sp. SBT8 strain for the decolorization and degradation of Reactive Orange 13 (RO13) was investigated. Conditions favorable for decolorization including temperature (25-42 °C), pH (5.0-10.0), culture age (0-24 h), and dye concentration (25-200 mg/L) were determined. Adding RO13 during the mid-exponential phase (8 h following inoculation) accelerated the rate of decolorization. Efficient decolorization was observed in broad pH (6.0-10.0) and temperature (25-35 °C) ranges with the optima at pH 7.0 and 33 °C, respectively. A complete decolorization was observed at pH 7.0, 35 °C, and 25 mg/L dye concentration in 48 h. Increased dye concentrations (over 100 mg/L) had inhibitory effects on the degradation of dye as measured after 48 h: 25, 50, and 100 mg/L dye concentrations were decolorized by 100, 83.58 ± 3.07, and 42.68 ± 3.02%, respectively. Decolorization and biodegradation were confirmed by UV-VIS spectroscopy, FTIR, and LC-MS. The analysis with FTIR affirmed the cleavage of the azo bond and the formation of novel products. The metabolites were determined by LC-MS analyses and a possible biodegradation pathway was proposed. Phytotoxicity was tested on Lens culinaris and the non-toxic nature of the metabolites was revealed. This study provides insights into the potentiality of Bacillus sp. SBT8 isolate on the decolorization and biodegradation of azo dyes.

Biomass Conversion and Biorefinery

Kurdistan Journal of Applied Research, 2018

Effect of transglutaminase, Maillard reaction induced crosslinking and the combination of transgl... more Effect of transglutaminase, Maillard reaction induced crosslinking and the combination of transglutaminase and Maillard reaction induced crosslinking between whey proteins and caseins in milk on calcium milk gel properties were investigated. Treatment of milk with transglutaminase, Maillard reaction, and transglutaminase + Maillard reaction cause to the appearance of new high MW protein bands. Water holding capacity, gel strength and sensory scores of gel samples increased and spontaneous whey separation decreased in calcium-induced milk gel made from transglutaminase and combination of transglutaminase and Maillard reaction treated milk compare with calcium-induced milk gel made from untreated milk alone.

Journal of Zankoy Sulaimani - Part A