Chapters authored
Antioxidant Capacity and Food Pathogenic Bacteria Inhibition of Citrus limetta and Citrus reticulata
In this study, phenolic compounds in the juice, seed and bagasse of C. limetta and C. reticulata cultivated in Mexico at two ripening stages were determined, and their antioxidant capacities were evaluated using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2′-azin-bis-(3-etilbenzotiazolin-6-sulfonic acid) (ABTS) and oxygen radical absorption capacity test (ORAC) methods, as well as their antibacterial growth inhibition. We found that bagasse had the highest total phenol content and the highest total flavonoid content. The dominant flavonoid, hesperidin, was observed to be the highest in bagasse. Ascorbic acid was analyzed and C. limetta juice and C. reticulata bagasse had the highest contents. Antioxidant capacity showed variations in both, C. limetta and C. reticulata, juices which had the highest ABTS value; C. limetta juice and C. reticulata bagasse had the highest DPPH value; C. limetta juice and C. reticulata bagasse had the highest ORAC value. C. limetta and C. reticulata extracts showed the bactericidal effect at the range of 4–40 mg/mL, assayed against Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella enterica and Staphylococcus aureus. Overall, ripeness increased total phenol content (TPC), total flavonoid content (TFC), hesperidin content, antioxidant capacity and bactericidal effect. These results may provide useful information for future utilization of C. limetta and C. reticulata.
Part of the book: Citrus
Sulfided NiMo/Clinoptilolite Catalysts for Selective Sulfur Removal from Naphtha Stream without Olefin Hydrogenation
The natural clinoptilolite zeolite has been modified by acid leaching with HNO3 in order to obtain economic material for supporting NiMoS hydrotreating catalysts. The most optimized zeolite material was obtained by leaching with HNO3 at 80°C during 24 h. The bimetallic NiMo catalysts prepared by wet impregnation of a zeolite support, followed by calcination and sulfidation, were characterized by several physico-chemical techniques and tested in the hydrodesulfurization (HDS) of 3-methyl-thiophene (3-MT) model feed at atmospheric H2 pressure and T = 280°C. For all catalysts, the 3-MT transformation mainly occurs via direct desulfurization reaction route being diminished the catalyst hydrogenation function. This was linked with the formation of highly stacked layers of MoS2 particles having a low amount of “brim sites,” as demonstrated by HRTEM. The cause of the best performance of Ni-Mo(H)/Z-1 sulfide catalyst in the HDS of 3-MT can be the presence of K+ impurities on the support surface which forces the formation of highly stacked layers of MoS2 particles.
Part of the book: Advances in Microporous and Mesoporous Materials