Determination of biogenic amines in chicken, beef, and mutton by dansyl chloride microwave derivatization in Malaysia.

In this study, an improved dansyl-chloride derivatization technique using a microwave synthesizer was used for the qualitative and quantitative analyses of biogenic amine in the fresh meat samples. The derivatization technique was optimized in terms of temperature, reaction time, and spinning speed. The derivatization method together with a validated reversed-phase HPLC-DAD method was used for the determination of biogenic amines in chicken, beef, and mutton sold in the wet market. The results of the analyses showed that tryptamine, putrescine, and histamine were generally detected in all the three types of meat. Higher levels of histamine were found in chicken and beef. However, low levels of histamine were observed in mutton. Tyramine was either detected low or moderate in all the three types of meat. The biogenic amines of the fresh meat sold in the wet market is generally higher than the reported values. The mechanisms of biogenic amines-dansyl-chloride formation were investigated and proposed. PRACTICAL APPLICATION: The biogenic amine derivatization method was improved. The improved derivatization method can be potentially used for various food products beside meats for routine biogenic amine analyses due to its fast analysis time and simplicity. High levels of biogenic amines were generally found in the meat sold in the wet markets. However, proper handling of the raw meat can reduce the risk of infection.

Metabolomic Approach for Rapid Identification of Antioxidants in Clinacanthus nutans Leaves with Liver Protective Potential.

Antioxidants are currently utilized to prevent the occurrence of liver cancer in non-alcoholic fatty liver disease (NAFLD) patients. Clinacanthus nutans possesses anti-oxidative and anti-inflammatory properties that could be an ideal therapy for liver problems. The objective of this study is to determine the potential antioxidative compounds from the C. nutans leaves (CNL) and stems (CNS). Chemical- and cell-based antioxidative assays were utilized to evaluate the bioactivities of CNS and CNL. The NMR metabolomics approach assisted in the identification of contributing phytocompounds. Based on DPPH and ABTS radical scavenging activities, CNL demonstrated stronger radical scavenging potential as compared to CNS. The leaf extract also recorded slightly higher reducing power properties. A HepG2 cell model system was used to investigate the ROS reduction potential of these extracts. It was shown that cells treated with CNL and CNS reduced innate ROS levels as compared to untreated controls. Interestingly, cells pre-treated with both extracts were also able to decrease ROS levels in cells induced with oxidative stress. CNL was again the better antioxidant. According to multivariate data analysis of the 1H NMR results, the main metabolites postulated to contribute to the antioxidant and hepatoprotective abilities of leaves were clinacoside B, clinacoside C and isoschaftoside, which warrants further investigation.

Antioxidant-rich Clove Extract, A Strong Antimicrobial Agent against Urinary Tract Infections-causing Bacteria in vitro.

Clove (Syzygium aromaticum) is an exotic culinary spice that has been used for centuries due to its known antimicrobial and antioxidant properties. The main aim of this study is to compare the antimicrobial activity and antioxidant capacity of clove ethanolic extract (CEE) and commercial clove essential oil (CEO) at a standardised eugenol content. Disk diffusion assay showed that CEE (2000 µg) was able to exhibit broad-spectrum inhibition against both Gram negative and Gram positive Urinary Tract Infections (UTIs)-causing pathogens: Proteus mirabilis (19.7 ± 0.6 mm) > Staphylococcus epidermidis (18 mm) > Staphylococcus aureus (14.7 ± 0.6 mm) > Escherichia coli (12.7 ± 0.6 mm) > Klebsiella pneumoniae (12.3 ± 0.6 mm) (according to the size of inhibition zone). Interestingly, the comparison between CEE and commercial CEO revealed that the former demonstrated stronger antimicrobial and antioxidative properties at similar eugenol concentration. The EC50 of DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and reducing power assay for CEE were determined as 0.037 mg/mL, 0.68 mg/mL and 0.44 mg/mL, respectively. Besides eugenol, High Performance Liquid Chromatography (HPLC) analyses identified the presence of kaempferol, gallic acid and catechin in CEE. As a conclusion, we concluded that there was a possible synergistic effect between eugenol and the others active compounds especially kaempferol which led to the observed bioactivities in CEE.

Bunga cengkih (Syzygium aromaticum) merupakan salah satu rempah masakan eksotik yang telah digunakan berabad-abad untuk kegunaan antimikrob dan antioksidan. Matlamat utama kajian ini adalah untuk membandingkan aktiviti antimikrob dan kapasiti antioksidan di antara ekstrak etanol bunga cengkih (CEE) dan minyak pati bunga cengkih komersial (CEO) dengan kandungan eugenol yang sama. Pencerakinan resapan agar menunjukkan CEE mempunyai perencatan spektrum yang luas terhadap bakteria Gram negatif dan Gram positif, patogen penyebab jangkitan saluran kencing: Proteus mirabilis (19.7 ± 0.6 mm) > Staphylococcus epidermidis (18 mm) > Staphylococcus aureus (14.7 ± 0.6 mm) > Escherichia coli (12.7 ± 0.6 mm) > Klebsiella pneumoniae (12.3 ± 0.6 mm) (menurut saiz zon perencatan). Yang menarik, perbandingan CEE dan CEO mendedahkan bahawa CEE menunjukkan aktiviti antibakteria yang kuat. Hapus-sisa radikal bebas DPPH dan ABTS serta aktiviti kuasa redaksi untuk rempah ini telah dibandingkan dengan CEO. Keputusan menunjukkan aktiviti antioksidan dalam CEE adalah lebih kuat. EC50 DPPH, ABTS dan pencerakinan kuasa redaksi untuk CEE masing-masing telah ditentukan sebagai 0.037 mg/mL, 0.68 mg/mL and 0.44 mg/mL. Kompaun aktif (eugenol dan lainlain kompaun fenolik) merupakan kompaun yang terkandung dalam CEE. Analisis HPLC mengkuantitikan kehadiran kaempferol, asid galik dan katechin. Kesimpulannya, kita menjangkakan kemungkinan terdapat kesan sinergi di antara eugenol dengan kompaun fenolik lain terutamanya kaempferol yang berupaya meningkatkan aktiviti CEE berbanding dengan CEO.

Palm oil mill effluent as the pretreatment solvent of oil palm empty fruit bunch fiber for fermentable sugars production.

Pretreatment is an essential upstream process to deconstruct oil palm empty fruit bunch fiber (OPEFBF) prior to sugars production. This study aimed to investigate the efficiency of OPEFBF pretreatment using palm oil mill effluent (POME) as solvent. The effect of alkali catalyst (5%w/w NaOH and ammonia), temperature (90,120,135 °C) and time (60,120,180 min) on the efficiency of pretreatment (OPEFBF-to-solvent ratio of 1:25) was also investigated. The results indicated that POME-pretreatment (135 °C, 180 min) enhanced glucose yield by only ~56%. Glucose production was increased about 5.8-fold to 495.3 ± 5.9 mg g-1 OPEFBF when NaOH was added in POME-pretreatment (Na-P). The xylose production from OPEFBF was increased about 3.7-fold after ammonia-catalyzed POME-pretreatment. About 12.1 ± 0.2 g L-1 of ethanol was produced from Na-P-hydrolysate at molar conversion of 59.4 ± 1.4%. This research provides new insight into the use of POME as a cost-effective pretreatment solvent of OPEFBF to reduce upstream process cost by cutting down water usage.