Gerardo Zepeda

Dr. Gerardo Zepeda

Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala, Ciudad de Mexico 11340, Mexico
orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
26 March 2020 in ChemCatChem
Verified
Journal Article
Closed access
PDF file
JCJavier Cervantes‐González
Javier Cervantes‐González
DVDavid A. Vosburg
David A. Vosburg
SMSalma E. Mora‐Rodriguez
Salma E. Mora‐Rodriguez
MVMiguel Vazquez
Miguel Vazquez
GZGerardo Zepeda
Gerardo Zepeda
SLSELENE LAGUNAS-RIVERA
SELENE LAGUNAS-RIVERA

1 December 2017 in Food Research International
Verified
Journal Article
Closed access
EBElvia Becerra-Martínez
Elvia Becerra-Martínez
EFElideth Florentino-Ramos
Elideth Florentino-Ramos
Nury Perez-HernandezNury Perez-Hernandez
Nury Perez-Hernandez
GZGerardo Zepeda
Gerardo Zepeda
Nemesio Villa-RuanoNemesio Villa-Ruano
Nemesio Villa-Ruano
ABAngel Ernesto Bañuelos-Hernández
Angel Ernesto Bañuelos-Hernández

1 April 2018 in Food Research International
Verified
Journal Article
Closed access
NVNayelli Villalón-López
Nayelli Villalón-López
JOSE IVAN SERRANO CONTRERASJOSE IVAN SERRANO CONTRERAS
JOSE IVAN SERRANO CONTRERAS
DTDarío I. Téllez-Medina
Darío I. Téllez-Medina
GZGerardo Zepeda
Gerardo Zepeda

16 July 2020 in Applied Sciences
Verified
Journal Article
Open access
PDF file
GAGabriela Aguilar-Hernández
Gabriela Aguilar-Hernández
GZGerardo Zepeda
Gerardo Zepeda
MGMaría de Lourdes García-Magaña
María de Lourdes García-Magaña
MVMaria De Los Angeles Vivar Vera
Maria De Los Angeles Vivar Vera
Alejandro Perez-LariosAlejandro Perez-Larios
Alejandro Perez-Larios
Efigenia Montalvo-GonzálezEfigenia Montalvo-González
Efigenia Montalvo-González
The main goal of this work was to measure the total alkaloid content (TALC) from pulp, peel, seed, and columella of soursop fruit (Annona muricata L.) by ultrasound-assisted extraction (UAE) and to obtain the best conditions of the UAE with the response surface methodology (RSM). We evaluated the effect of amplitude (40%, 70%, and 100%), time (5, 10, and 15 min) and pulse-cycles (0.4, 0.7, and 1 s) and compared the best UAE conditions of alkaloids with a conventional extraction (maceration). The structural characterization of the raw material with the highest TALC was developed using nuclear magnetic resonance (NMR) techniques [1H, 13C, heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), and homonuclear correlation spectroscopy (COSY)]. According to the RSM, the best conditions in the UAE for extracting alkaloids varied depending on the type of plant tissue. It took 5 min with an amplitude of 70% and pulse-cycles of 1, 0.4, and 1 s, respectively, to extract the highest TALC in peel, seed, and columella while the optimal conditions for extracting the largest amount of alkaloids from the pulp were obtained at 5 min in UAE with pulse-cycles of 0.55 s and 100% amplitude. The TALC was highest in the peel (7.48 mg/g), which was followed by the seed (2.31 mg/g), the pulp (1.20 mg/g), and the columella (0.79 mg/g) and was positively correlated (R2 = 0.98–0.88) with the predicted values. In addition, the extraction alkaloids from the peel, pulp, seed, and columella using the UAE was 56.31, 5.45, 3.06, and 2.96 times higher, respectively, than the extraction by maceration. The alkaloids identified in the peel have not been reported and were nornuciferin, assimilobin, anonaine, and isolaureline. This study showed that the soursop fruit peel can be a source of alkaloids and that UAE has an important potential for extracting these compounds.

15 February 2019 in Journal of Food Science
Verified
Journal Article
Open access
PDF file
CLCarlos A. López‐Morales
Carlos A. López‐Morales
SVSaid Vázquez‐Leyva
Said Vázquez‐Leyva
Luis Vallejo-CastilloLuis Vallejo-Castillo
Luis Vallejo-Castillo
GCGregorio Carballo‐Uicab
Gregorio Carballo‐Uicab
LMLeslie Muñoz‐García
Leslie Muñoz‐García
EMEmilio Medina-Rivero
Emilio Medina-Rivero
Collagen hydrolysates are dietary supplements used for nutritional and medical purposes. They are complex mixtures of low‐molecular‐weight peptides obtained from the enzymatic hydrolysis of collagen, which provide intrinsic batch‐to‐batch heterogeneity. In consequence, the quality of these products, which is related to the reproducibility of their mass distribution pattern, should be addressed. Here, we propose an analytical approach to determine the peptide pattern as a quality attribute of Colagenart®, a product containing collagen hydrolysate. In addition, we evaluated the safety by measuring the viability of two cell lines exposed to the product. The consistency of peptide distribution was determined using Size Exclusion Chromatography (SEC), Mass Spectrometry coupled to a reversed phase UPLC system (MS‐RP‐UPLC), and Shaped‐pulse off‐resonance water‐presaturation proton nuclear magnetic resonance spectrometry [ 1 Hwater_presat NMR]. The mass distribution pattern determined by SEC was in a range from 1.35 to 17 kDa, and from 2 to 14 kDa by MS‐RP‐UPLC. [ 1 Hwater_presat NMR] showed the detailed spin‐systems of the collagen hydrolysates components by global assignment of backbone Hα and NH, as well as side‐chain proton resonances. Additionally, short‐range intraresidue connectivity pathways of identified spin‐regions were obtained by a 2D homonuclear shift correlation Shaped‐pulse solvent suppression COSY scheme. Safety analysis of Colagenart® was evaluated in CaCo‐2 and HepG2 cells at 2.5 and 25 μg/mL and no negative effects were observed. The results demonstrated batch‐to‐batch reproducibility, which evinces the utility of this approach to establish the consistency of the quality attributes of collagen hydrolysates. Practical Application: We propose state‐of‐the art analytical methodologies (SEC, MS, and NMR) to evaluate peptide profile and composition of collagen hydrolysates as quality attributes. These methodologies are suitable to be implemented for quality control purposes.

18 November 2022 in Recycling
Verified
Journal Article
Open access
PDF file
ICIrlanda G. Cruz-Reyes
Irlanda G. Cruz-Reyes
JMJorge Alberto Mendoza-Pérez
Jorge Alberto Mendoza-Pérez
MRMaria del Rosario Ruiz-Guerrero
Maria del Rosario Ruiz-Guerrero
DMDulce Yolotzin Medina-Velázquez
Dulce Yolotzin Medina-Velázquez
GZGerardo Zepeda
Gerardo Zepeda
Angel De Jesús Morales-RamírezAngel De Jesús Morales-Ramírez
Angel De Jesús Morales-Ramírez
A choline chloride/urea natural deep eutectic solvent (ChCl NADES) was prepared via a green chemistry method and used to leach Zn and Mn oxides from conventional Zn–C scrap batteries. FTIR and 1H NMR spectroscopy were used to characterize the NADES. The leaching kinetics of the Zn and Mn oxides was monitored at isothermal conditions (80, 100, 125, and 150 °C) and at two solid/NADES ratios: 3.3 and 10 g dm−3. It was possible to dissolve Zn and Mn oxides under all of tested conditions, reaching more than a 95% recovery for both metals at 150 °C after 90 min, whereas, at 25 °C, it was possible to leach up to 90% of the Zn and 30% of the Mn after 4320 min (72 h). Furthermore, the leaching kinetics was controlled by the boundary layer, coincident with a shrinking core model. According to the Arrhenius plot, the activation energy for Zn ranges from 49.13 to 52.21 kJ mol−1, and that for Mn ranges from 46.97 to 66.77 kJ mol−1.