Paprika extract as a natural antioxidant in cold-stored pork patties: Effect on oxidative stability and heterocyclic amines inhibition.

In this study, we compared the degree of oxidation of pork patties refrigerated at 7 °C for 0, 7, and 14 days and the content of 10 types of heterocyclic amines (HCAs) after heating. The pork patties used in the study were added with 0.7 mg sodium nitrite (SN) and 5 mg paprika extract (PE), respectively. IQx (2-Amino-3-methyl-imidazo[4,5-f]-quinoxaline), MeIQx (2-Amino-3, 8-dimethyl-imidazo[4,5-f]-quinoxaline), PhIP (2-Amino-1-methyl-6-phenyl-imidazo[4,5-b]-pyridine), and Harman (1-Methyl-9H-pyrido[4,3-b]-indole) contents increased with increasing storage periods of treatment. On the other hand, HCAs production in SN and PE treatments were suppressed over the storage period, with IQ (2-Amino-3-methyl-imidazo[4,5-f]-quinoline) and Aαc (2-Amino-9H-dipyrido[2,3-b]-indole) being suppressed significantly (P < 0.05). The control's pH, cooking loss, lipid, and protein oxidation were higher than SN and PE-treated patties at 14 d (P < 0.05). These differences affect the formation of HCAs. PLS-DA showed a strong correlation between protein oxidation and IQx, Harman, 4,8-DiMelQx (2-Amino-3, 4, 8-trimethyl-imidazo[4,5-f]-quinoxaline), PhIP, and MeIQx, while lipid oxidation correlated with IQx, Harman, and PhIP. Both SN and PE showed HCAs inhibitory activity and exhibited oxidative stability during storage.

Inhibitory and antioxidative capacity of nutmeg extracts on reduction of lipid oxidation and heterocyclic amines in pan-roasted beef patties.

Identification and inhibition of mutagenic and carcinogenic heterocyclic amines (HCAs) from pan-roasted beef patties were performed by adding (0.02%) tertiary butyl hydroquinone (TBHQ) and (0.05%) ethanol-extracted nutmeg (ENE) using HPLC and principal component analysis. Ten HCAs, including six polar and four non-polar, were assessed. The addition of (0.05%) ENE significantly (P < 0.05) reduced the cooking loss and shrinkage of patties during cooking and reduced the total formation HCAs by 73.97%, which proved the significant (P < 0.05) inhibitory effect as a natural antioxidant against lipid oxidation and HCA formation compared to TBHQ. The DPPH radical-scavenging activity, total phenolic content, and available active metabolites of ENE were estimated. Furthermore, a positive correlation was observed between pH, level of thiobarbituric acid reactive substances, and HCA formation in both the groups. TBHQ and ENE were significant HCAs inhibitors (P < 0.001), but ENE showed resilient oxidative stability during refrigeration storage. Therefore, ENE can be used to reduce HCAs formation in pan-roasted beef patties.

Phylogenetic analysis and characterization of arsenic (As) transforming bacterial marker proteins following isolation of As-tolerant indigenous bacteria.

Marker proteins play a significant role in bacterial arsenic (As) transformation. Phylogenetic analysis and three-dimensional (3D) characteristics of As transforming bacterial marker proteins guide the evolutionary origin and As transforming potential of the species. Indeed, As-tolerant bacteria also show a significant level of As transformation. Hence, characterization of As transforming bacterial marker proteins, isolation of As transforming bacteria, and proper integration of the findings may guide to elucidate how bacteria transform As. Therefore, phylogenetic analysis and 3D characterization of As transforming bacterial marker protein following isolation of potential indigenous As-tolerant indigenous bacteria were done to explore the mechanism of bacterial As transformation. Phylogenetic analysis of ten As transforming marker proteins (arsA, arsB, arsC, arsD, arsR, aioA, arrA, aioB, acr1, and acr3) in 20 potential bacterial genomes (except 19 for the acr3) were studied. Some bacterial genomes featured up to five marker proteins, and therefore, 3D characteristics of the marker proteins were analyzed in those genomes having three-to-five marker proteins. In phylogeny, species in close clades represent their phylogenetic resemblances and may have similar functions. P. aeruginosa, E. coli, and K. pneumonia were found to be more effective due to having the highest number (five) of marker proteins. In 3D protein modeling, most of the marker proteins were found to be active. Among 19 indigenous bacterial isolates, multiple isolates showed tolerance up to 50 mM As(III) and 250 mM As(V), which may potentially transform a significant quantities of As. Hence, integration of the results of phylogenetic analysis, 3D protein characteristics, and As tolerance in the bacterial isolates could guide to explore the mechanism of how bacteria transform As at cellular and molecular levels.