Member Profile
Stephania Aragón Rojas
Country of origin: Colombia Currently in: Colombia, Cajica, Cundinamarca General field of specialization: Biological Systems and Organisms-
Degrees
2018 Doctorate Engineering sciences2013 Master Structural, Cell and Molecular Biology2009 Undergraduate Biological Systems and Organisms -
Current Research Activities
Other
I’ve been working as a doctoral student in the laboratories of Dr. Maria Ximena Quintanilla Carvajal and Dr. Ruth Yolanda Ruiz at University of La Sabana (Chía, Cundinamarca, Colombia), Dr. Humberto Hernandez Sanchez at National Polytechnic Institute (Ciudad de México, Mexico) and Dr. Yves Arcand, Dr. Patrick Fuster and Dr. Alan Hernandez at Agriculture and AgriFood Canada, Food Research and Development Centre (Saint Hyacinth, Quebec, Canada); where I developed a culture medium for Lactic acid bacteria with probiotic potential (LAB – PP), it had a double function as nutritional source and carrier material for encapsulation processes. Also, I used different strategies to encapsulate LAB - PP isolated from typical Colombian food and to conserve the probiotic characteristics and the cell count to have an effect on the consumer health. The strategies were to use whey proteins as carrier material in combination with drying technologies (Refractance windowTM, Freeze-drying and Spray-drying). I tested the best capsules in in vitro dynamic Digestion System and in in vitro gastrointestinal statics systems. The capsules were characterized in size, form, colour, hygroscopicity, compacted density, moisture, water activity, and were estimated the shelf life. The behaviour of the microorganisms during drying process and in gastrointestinal conditions was studied using mathematical models. The aim of the research was to find an industrial process for the encapsulation of the LAB from the culture medium to powder product to use in develop functional food. Finally, the important outcomes of this research were: i) the designed culture medium increased the biomass concentration to 10.051 ± 0.39 Log10 CFU/mL and it decreased the adaptation period to 1.302 ± 0.313 h-1 and it may generate a stress factor for the microorganism, which affects the bacteria ability to tolerate the gastrointestinal conditions; ii) the use of culture medium as a component of the carrier material and as carrier material favoured the survival of L. fermentum K73 after spray drying, freeze-drying and Refractance windowTM processes; iii) Refractance windowTM proved to be a promising technology for the encapsulation of probiotics; iv) the culture medium spray-dried is proposed as a powder product for the elaboration of functional foods at low cost after the study of shelf life and the evaluation in the in vitro Digestion System.
Publications resulting from Research:
1- Aragón-Rojas S , Hernández-Álvarez A.J , Mainville I , Arcand Y , and Quintanilla-Carvajal M. X (2020).
Effect of the carrier material, drying technology and dissolution media on the viability of Lactobacillus
fermentum K73 during simulated gastrointestinal transit. Food Funct. 2020;11(3):2339-2348.
doi:10.1039/c9fo01091b.
2- Aragón-Rojas S, Quintanilla-Carvajal M.X., Hernández-Álvarez A.J., Champagne C.P., Fustier P. and
Arcand, Y. (2020). S/O/W emulsions prepared with whey proteins enhance the viability Lactobacillus
fermentum K73. Submitted in Food & Function.
3- Aragón-Rojas, S., Ruiz-Pardo, R. Y., Hernández-Álvarez, A. J., and Quintanilla-Carvajal, M. X. (2019).
Sublimation conditions as critical factors during freeze-dried probiotic powder production. Drying Technology:
An International Journal. https://doi.org/10.1080/07373937.2019.1570248
4- Aragón-Rojas, S., Quintanilla-Carvajal, M. X., Hernández-, H., Hernández-Álvarez, A. J., and Moreno, F.
L. (2019). Encapsulation of Lactobacillus fermentum K73 by Refractance Window drying. Scientific Reports,
1–15. https://doi.org/10.1038/s41598-019-42016-0
5- Aragón-Rojas, S., Ruiz-Pardo, R. Y., Hernández-Sánchez, H., and Quintanilla-Carvajal, M. X. (2018).
Optimization of the production and stress resistance of the probiotic Lactobacillus fermentum K73 in a
submerged bioreactor using a whey-based culture medium. CyTA - Journal of Food, 16(1), 1064–1070.
https://doi.org/10.1080/19476337.2018.1527785
6- Aragón-Rojas, S., Quintanilla-Carvajal, M. X., and Hernández-Sánchez, H. (2018). Multifunctional Role of
the Whey Culture Medium in the Spray-Drying Microencapsulation of Lactic Acid Bacteria. Food Technology
and Biotechnology, 56(3). https://doi.org/10.17113/ftb.56.03.18.5285
7- Aragón-Rojas, S., Quintanilla-Carvajal, M. X. (2016). Aprovechamiento del suero de leche como matriz
acarreadora de microorganismos probióticos: tolerancia a condiciones gastrointestinales. En Buera, M.P y
Román-Santagapita, P. (Ed.), “Aprovechamiento de subproductos y valorización de recursos autóctonos:
interrelación investigación, producción, desarrollo y sociedad” (p. 61-64). Buenos Aires: Red Temática
415RT0495 “LACFUN”.
PATENTS GRANTED BY THE SIC IN COLOMBIA
1. Culture medium with whey proteins and extract yeast
Date: August 16th, 2016.
Number: NC2016/0000830
Issuing entity: Superintendence of Industry and Commerce (SIC - Spanish acronym).
2. Encapsulation process for probiotics
Date: August 10th, 2017.
Number: NC2017/0008058
Issuing entity: Superintendence of Industry and Commerce (SIC - Spanish acronym)
As a master student under the guidance of Professor Maria Clementina Cueto at University of La Sabana; I primarily focused on the isolation, purification, and molecular identification of soil bacteria and lactic acid bacteria. With the soils bacteria I developed a mixture of Azotobacter sp., with Azospirillum spp., with properties for stimulating of growth plant and a phytopathogen agent. With the lactic acid bacteria I characterized as probiotics strains and I identified two mechanisms to low the cholesterol in in vitro conditions, adsorb the cholesterol on the cell membrane and the enzymatic activity of the bile salt hydrolase. With this study we contributed to the university strain bank and the study of the LAB with industrial application. So, with my experience in BSH molecular and enzymatic activity I can to contribute with the aim of the position. In my master research, I proposed a enzymatic mechanism to BSH in L. fermentum (only one with multiple substrate), because the enzyme is different than L. acidophilus or L. rhamnosus. The finding of potential probiotics with hypocholesterolemic activity led to an investigation to develop and specific Colombian probiotic product to decrease the serum cholesterol using the encapsulation process, my Ph. D thesis.
In my bachelor, I did the thesis "Identification and detection of Gram-positive and Gram-negative bacteria that cause neonatal sepsis through the polymerase chain reaction". I designed a bacterial DNA extraction protocol from neonatal blood (500 μL or less) because the conventional protocols use more than 1 mL and this amount of blood could cause anemia on the neonates. Then, I did the standardization of the polymerase chain reaction to identify Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae from clinic samples. The results were consistent with the microbiology identification of the strains and I could decrease the diagnostic time from 4 -5 days to 1 day. With this study the research group started to develop new protocols to identify the nosocomial diseases using different clinic samples.
1- Cueto C., Aragón S. (2012) Evaluación del potencial probiótico de bacterias ácido lácticas para reducir el
colesterol in vitro. Scientia Agropecuaria; 3:45-50.
2- Cueto, C., Acuña, Y., Aragón R, S.(2009). “Cuantificación de ácido láctico de bacterias aisladas del suero costeño”, VII Congreso Iberoamericano de Ingeniería de Alimentos, Colombia
Current profession
Current professional activities type:Research
