Browsing by Author "Ortiz Ulloa, Silvia Johana"

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12th IFDC 2017 special issue – seasonal variations in nutrient composition of plant-based foods produced at the southern highlands of Ecuador
(2019) Ortiz Ulloa, Silvia Johana; Astudillo Rubio, Gabriela Cristina; Castro Arteaga, Evelyn Michelle; Castro Nube, Cecilia; Astudillo Astudillo, Sonia Cecilia; Donoso Moscoso, Silvana Patricia
Changes in environmental conditions may influence the biosynthesis of several food nutrients. This study aimed to compare macronutrient and mineral composition over several seasons in 25 fresh plant-based foods that are highly consumed and locally produced in the southern Ecuadorian highlands. Samples were collected during the rainy season (October 2015–March 2016) and dry season (April–September 2016) from main local markets and supermarkets. Analyses of composite samples were carried out in triplicate following AOAC methods, determining moisture by desiccation, ash by calcination, total fat by Weibull, total nitrogen by Kjeldahl, total carbohydrates by difference, phosphorus by colorimetry, and minerals (Na, K, Mg, Ca, Fe, Se, Cu and Zn) by atomic absorption spectroscopy. Overall, during the rainy season, significantly higher moisture content was observed (86.7 ± 9.0% vs. 85.9 ± 8.9%, p < 0.001), whereas fat (0.21 ± 0.21% vs. 0.31 ± 0.24%, p = 0.001), Fe (0.79±1.31 vs. 0.61 ± 0.98 mg/100 g, p < 0.001), Ca (50.4±68.0 vs. 23.0 ± 37.3 mg/100 g, p < 0.001), Mg (18.0 ± 11.4 vs. 15.2 ± 10.8 mg/100 g, p < 0.001) and Zn (0.35±0.69 vs. 0.2 ± 0.16 mg/100 g, p = 0.026 were significantly lower. This study demonstrates the influence of the season in the composition of vegetables cultivated in Ecuador. This factor, along with other sources of variability, should be defined, so as to be included in the quality assessments of representative food composition data. © 2019 Elsevier Inc.
Acute oral toxicity of a novel functional drink based on Ilex guayusa, Vernonanthura patens, and cocoa husk
(2021) Iñiga Alvarado, Elsy Catalina; Sarmiento Tomalá, Glenda Marcela; Orellana Manzano, Andrea Katherine; Paladines Santacruz, Geovanna Lissette; Pilozo Muentes, Glenda Margarita; Berghe, Wim Vanden; Manzano Santana, Patricia Isabel; Villacres Cevallos, María del Carmen; Orellana Manzano, Silvia Gabriela; DI GRUMO, DAVIDE; Quijano Aviles, Maria Fernanda; Ortiz Ulloa, Silvia Johana; ; Zaruma Torres, Fausto Leonardo
A novel functional drink with nutraceutical properties was formulated from the aqueous extracts of Ilex guayusa, and Vernonanthura patens leaves, and cocoa husks. This juice contains various bioactive compounds, such as phenolic compounds and methylxanthines, with antioxidant and stimulant properties of pharmacological interest. However, it is known whether herbal extracts' interaction may have adverse toxic effects on human health. To evaluate this functional drink's innocuity, we estimated the acute oral toxicity (AOT) in experimental mice. This paper presents the AOT evaluation of two formulations of a functional drink (pre-formulation and microencapsulation) at a single dose of 2000 mg/kg of body weight (b.w.). No signs of adverse toxicity and mortality were observed after a single oral dose of 2000 mg/kg b.w. Likewise, no significant body and organ weight changes, food and water consumption behavior, and no histopathological changes were observed in the main organs evaluated. In conclusion, this functional drink can be categorized as low toxicity " according to the Globally Harmonized Classification System (GHS), making it a potential beverage with high nutritional and pharmacological value.
Analisis bromatológico inter-laboratorio de harina de centeno a ser utilizado como patrón secundario de análisis
(2016) Cabrera Medina, Jorge Omar; Peralta Herrera, Jessica Valeria; Ortiz Ulloa, Silvia Johana
The objective of this research was to perform an inter-laboratory study using a secondary standard of rye flour for food analysis. The participating laboratories in this comparative study were the Laboratory of Food Analysis for public service ofthe Cuenca University and the Laboratory of Food and Nutrition (VLIR-IUC) of the Department of Biosciences of Cuenca University. The analytical parameters were: humidity, dry matter, ash, total protein, total fat and total carbohydrates. Also, salt content (chlorides) was determined in one of the laboratories. For the analysis of the different parameters, the established methodologies in each laboratory were utilized. With the generated data, Levey-Jennings control charts were made for each parameter and laboratory for further control using the secondary standard in both of the participating laboratories. The results were statistically evaluated by means of one tailed T Student tests with a significance level of 5%. Also,intra (within) - and inter (between)-day precision were determined following the ANOVA method and were expressed as coefficient of variation in percentage(%CV). All the statistical analyses were executed in the Microsoft Excel and STATA 10.0 programs.For both laboratories, the intra- and inter- day coefficients of variation did not surpass 15%, which is the recommended value for proximate analysis. On the other hand, significant differences were found in the analysis of fat, humidity-dry matter and carbohydrates, which can be attributed to the differences in the methodologies, temperature and analysis equipment, and in a minor degree to the personnel of analysis and random error.
Análisis de la composición de la quinua cruda, cocida y tostada
(Universidad de Cuenca, 2025-09-04) Mejía Quizhpi, Liliana Elizabeth; Pillajo Pérez, Cristina Raquel; Ortiz Ulloa, Silvia Johana
Quinoa is a pseudocereal considered a superfood due to its high nutritional content and bioactive compounds. The objective of this undergraduate thesis was to evaluate the nutritional composition of quinoa sold in the city of Cuenca in its raw, cooked, and toasted forms. Samples of raw quinoa were collected from different points of sale following a random sampling method. A composite sample was prepared, and from this, a portion was taken to be subjected to cooking in water and another to a toasting process, both at a laboratory level. In the three types of quinoa samples, the proximate composition (total carbohydrates, total lipids, total proteins, moisture, and ash) was determined in triplicate. Additionally, the mineral composition was determined by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The results obtained showed that cooked quinoa presented the lowest values in ash content (0.5%), fats (1.9%), and proteins (4.7%), while moisture increased from 12.0 to 78.6% due to the absorption of cooking water, causing a loss of minerals by leaching. In toasted quinoa, the mineral content increased, with Ca showing the highest increment (1.3 times). In conclusion, the composition of quinoa can be affected by the cooking process, while in the toasted form it presents a slight increase in proteins, carbohydrates, and minerals due to the drying of the grain, which is why this preparation is the most recommended for a daily diet.
Aplicación del sistema de categorización LanguaLTM como herramienta de estandarización descriptiva de la “tabla composición de alimentos de Cuenca, Ecuador”
(Universidad de Cuenca, 2025-09-03) Freire Benenaula, Sofía Isabel; Toalongo Morquecho, Juan Andres; Ortiz Ulloa, Silvia Johana; Saquicela Carpio, Jorge Eduardo
The LanguaLTM tool is a thesaurus developed to classify and describe different types of food products. It is used worldwide and enables the exchange of food composition data between different regions of the world. This thesis work is oriented towards the application of the LanguaLTM categorization system in order to standardize foods of Andean origin that are presented in the 2018 edition Food Composition Table of Cuenca, Ecuador. In addition, a standard protocol was developed for the categorization of foods of local origin, facilitating the coding of 129 foods. The results obtained evidenced limitations in some foods of traditional Ecuadorian cuisine and regional food patterns were found. Systematization facilitates the communication of data between platforms in an international manner, promoting food sovereignty and optimizing the creation of food policies. The implementation of this methodology improves the efficient and accurate interpretation of nutritional information in the country.
Bioacumulación y biomagnificación de metales pesados en peces, moluscos y crustáceos de mayor consumo en las costas de países sudamericanos. Revisión de literatura
(Universidad de Cuenca, 2022-09-28) García Pesantez, María Paz; Rivadeneira Mejía, Génesis Cristina; Ortiz Ulloa, Silvia Johana
Heavy metals are an important source of contamination of the aquatic environment and, through it, of the beings that inhabit it turning out to be an important transfer resource in marine food webs, being of great relevance those species of greater demand for consumption since they could represent a greater risk for the health of consumers, which depends on the bioaccumulation and biomagnification processes of their species. The objective of this degree work was to provide information from published scientific studies on how the contamination of the aquatic environment with heavy metals (As, Cd, Hg and Pb) affects the most consumed marine species in the South American countries of Ecuador, Peru, Colombia and Chile and how these species bioaccumulate in their specific target organs and the manifestation of biomagnification. For this purpose, a review of the state of the art on these phenomena in fish, mollusks and crustaceans of major consumption in the coasts of South American countries was carried out, resorting to different databases of scientific publications and university digital repositories. Among the most relevant results is the report of bioaccumulation of As, Cd, Hg and Pb in several organs and tissues in many of the most consumed species in the countries mentioned, such as gills, liver, kidney, muscle, hepatopancreas and gonads. There is a lack of biomagnification studies of heavy metals in the species described; however, it was possible to identify that the most analyzed and most biomagnified metal is Hg.
Biological Pretreatment Effects on the Bioconversion of Brewer Spent Grain with Hermetia illucens Larvae
(2023) Ortiz Ulloa, Silvia Johana; Torres Ulloa, Angélica Malena; Jiménez Feijoo, María Isabelita; Ruiz Barzola, Omar Honorio; Chica Martínez, Eduardo José; Nieto Wigby, Julia Ruth; Sumba Zhongor, Martha Beatriz; Alava, Eduardo I; Galarza, Luis
Hermetia illucens is an important species for waste management and the circular economy. The aim of this study was to analyze the effects of Trichoderma reesei C2A and Pleurotus sp. as pretreatments of brewer spent grain (BSG). BSG was inoculated with fungal solution or distilled water (control). After seven days, this was used for H. illucens larvae cultivation. At the end of bioconversion process, parameters of substrate reduction and H. illucens larval development were evaluated. Chemical properties of BSG, frass and larvae were also analyzed. With T. reesei C2A pretreatment, highest substrate reduction (46.3 ± 0.9%) was achieved, but larval growth rate was lower (1.0 ± 0.1 mg/d) than that of control (2.8 ± 0.2 mg/d). Larvae of Pleurotus sp. pretreatment had limited development, reflected in their negative growth rate (−0.6 ± 0.2 mg/d). In conclusion, cultivation of H. illucens larvae (six day old) on BSG pretreated with Pleurotus sp. is not recommended. On the other hand, T. reesei C2A pretreatment enhance BSG reduction, and its potential use for lignocellulosic waste management should be more explored. © 2022 by the authors
Bioseguridad de negocios que expenden alimentos de manera virtual en la ciudad de Cuenca, Ecuador inscritos en el programa “Acolítame” en el periodo marzo – junio del 2021: asesoramiento virtual y evaluación microbiológica de superficies de los empaques
(Universidad de Cuenca, 2021-10-22) Mancheno García, María José; Sarmiento Acuña, Camila Isabel; Ortiz Ulloa, Silvia Johana
In recent times, the number of food-related businesses that are marketed and distributed through electronic means has increased. Given the uncertainty of the quality of these foods, the objective of this study was to evaluate the safety and hygiene of food in a group of small businesses that operate virtually (“electronic businesses”) through the development of training material, its application and ongoing advice on biosafety issues in the food industry. Its follow-up was carried out through surveys. At the same time, the safety and hygiene of the packaging and distribution of the food sold was monitored by analyzing the microbiological indicators of the packaging surfaces. Food-related businesses from the business group belonging to the “Acolítame” program were selected for the study. In total, we worked with 6 businesses, from which a total of 36 primary packaging samples were collected. With this study, it is expected to raise awareness among food producers about the use of good manufacturing practices and correct hygiene standards that result in a safe and suitable product for the consumer.
Caracterización de compuestos antioxidantes carotenoides y polifenoles presentes en las microalgas Chlorella sp. y Nannochloropsis oculata cultivadas in vitro con potencial nutricional
(2019-03-11) Romero Asanza, Jessenia Lizbeth; Ortiz Ulloa, Silvia Johana; Santos Ordoñez, Efrén Germán
Microalgae are an excellent source for the research and production of bioactive compounds. In this work, the antioxidant capacity of different extraction solvents in Chlorella was evaluated, and carotenoids and polyphenols were characterized in Chlorella sp. and Nannochloropsis oculata. Therefore, a methodology that includes optimized culture of microalgae, genetic identification with molecular biology tools, extraction with maceration and ultrasonication by hydrophilic solvents: ethanol/water 50:50 and 95:5 (v/v), and lipophilic solvents: dichloromethane and n-hexane, comparison of the antioxidant activity of the extracts obtained by the methods of capture of the free radical 2,2-diphenyl-1-picrylhydracil (DPPH), reducing power and the β-carotene bleaching, and chemical characterization in both microalgae by RP-HPLC-DAD, was used to relate its antioxidant activity with its chemical profile. The polar and apolar solvents most efficient in antioxidant activity in Chlorella were applied to N. oculata. It was perceived that the use of enriched cultures generated high concentrations of antioxidants. The molecular evaluation revealed similarity for Chlorella spp. with the ITS sequence. The results showed that the ethanol/water 95:5 and dichloromethane solvents provided the highest antioxidant activity in all the tests, which explains why the extracted compounds have multiple antioxidant mechanisms. Important concentrations of carotenoids (lutein, α- and β-carotene) and a phenolic compound (luteolina) were found in Chlorella sp. In contrast, in N. oculata, an important concentration of the carotenoid fucoxanthin. Apparently, the carotenoids found in Chlorella could explain the high observed antioxidant activity. The high production of lutein, especially, makes it a source with great nutritional potential.
Caracterización del proceso tradicional del pelado de maíz con ceniza a ser utilizado como estrategia de detoxificación de aflatoxinas y fumonisinas. Caso de estudio: Nabón – Ecuador
(2015-05-20) Molina Cando, María José; Ochoa Avilés, María Cristina; Ortiz Ulloa, Silvia Johana
The aim of this study was to characterize the process of dehulling maize using wood ash and to evaluate its effectiveness as a detoxification strategy for mycotoxins. Particurally, the presence of aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) and fumonisins B1 (FB1) and B2 (FB2) of 40 samples of dried and no-dehulled maize and 40 samples of wood ash dehulled maize from small producercs from Nabon were analyzed using high performance liquid chromatography with florescence detection (HPLC-FLD). Low prevalence of contamination with aflatoxins was observed in dried maize (2,5 % AFG2, 12,5% AFG1, 17,5% AFB2, 7,5%AFB1,) and an important prevalence of contamination with fumonisins (42,5% FB1, y 35% FB2); wich was reduced in dehulled maize (10,5% AFG1, 18% FB1 y 8% FB2). None of the samples exceed the maximum limits for aflatoxins established in Ecuador or FDA for fumonisin. The detoxifying effectiveness of the process of dehulling maize using wood ash was assessed by contrasting the concentrations of mycotoxins before and after the dehulling process, finding significant reductions in contamination for AFB1 (P = 0.004 ), AFB2 (P <0.001), FB1 (P = 0.033) and FB2 (P = 0.023). In addition, the influence of agricultural practices on aflatoxin and fumonisins contamination of maize was evaluated. Harvest in the period July-September was identified as a protective factor for AFG1 (OR; 0,087; IC: 0,008-0,87; P=0,039) and AFB2 (OR= IC: 0,128; P=0,027) . Also, cultivation in warm zones (OR=0,147; IC: 0,03-0,62; P=0,010) and rainwater irrigation (0,111; IC: 0,01-0,66; P=0,016) were identified as protective factors for FB2.
Changes in phytochemical composition, bioactivity and in vitro digestibility of guayusa leaves (Ilex guayusa Loes.) in different ripening stages
(2018) Villacís Chiriboga, José Eduardo; García Ruiz, Almudena; Baenas, Nieves; Moreno, Diego Angel; Meléndez Martínez, Antonio J.; Stinco, Carla M.; Jerves Andrade, María de Lourdes; León Tamariz, Fabián; Ortiz Ulloa, Silvia Johana; Ruales, Jenny
BACKGROUND: Guayusa (Ilex guayusa Loes.) leaves, native of the Ecuadorian Amazon, are popularly used for preparing teas. This study aimed to assess the influence of leaf age on the phenolic compounds and carotenoids and the bioactivity and digestibility (in vitro) of aqueous and hydroalcoholic leaf extracts. RESULTS: In total, 14 phenolic compounds were identified and quantified. Chlorogenic acid and quercetin-3-O-hexose were the main representatives of the hydroxycinnamic acids and flavonols respectively. Seven carotenoids were quantified, lutein being the main compound. Ripening affected phenolic content significantly, but there was no significant difference in carotenoid content. Antioxidant capacity, measured by the DPPH• method, was also significantly affected by leaf age. The measurement of in vitro digestibility showed a decrease in phenolic content (59%) as well as antioxidant capacity, measured by the ABTS•+ method, in comparison with initial conditions of the guayusa infusion. Antibacterial and anti-inflammatory activities were assayed with young leaves owing to their higher phenolic contents. Guayusa did not show any antibacterial activity against Escherichia coli ATCC 25922 or Staphylococcus aureus ATCC 25923. Finally, the hydroalcoholic and aqueous extracts exhibited high in vitro anti-inflammatory activity (>65%). CONCLUSION: Young guayusa leaves have potential applications as a functional ingredient in food and pharmaceutical industries. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry
Children’s and adolescents’ rising animal-source food intakes in 1990–2018 were impacted by age, region, parental education and urbanicity
(2023) Ochoa Avilés, Angélica María; Ortiz Ulloa, Silvia Johana
Animal-source foods (ASF) provide nutrition for children and adolescents’ physical and cognitive development. Here, we use data from the Global Dietary Database and Bayesian hierarchical models to quantify global, regional and national ASF intakes between 1990 and 2018 by age group across 185 countries, representing 93% of the world’s child population. Mean ASF intake was 1.9 servings per day, representing 16% of children consuming at least three daily servings. Intake was similar between boys and girls, but higher among urban children with educated parents. Consumption varied by age from 0.6 at [removed]
Comparación de los procesos de tratamiento de agua en las plantas Uchupucún Y Mahuarcay de la ciudad de Azogues
(2017) Calle Chimborazo, Rocío Filomena; Ortiz Ulloa, Silvia Johana
The present investigation is a comparative study of the purification processes of two conventional water treatment plants "Uchupucún" and "Mahuarcay" of the city of Azogues through the analysis of physical parameters (turbidity, conductivity and total solids) and Microbiological parameters (total coliforms and fecal coliforms). For the analysis of the different parameters, techniques established in national and international regulations were used. The determination of turbidity was made in the HACH 2100 AN USA equipment, conductivity and total solids were analyzed in the HACH - CONDUCTIVITY / TDS METER USA equipment. Total and fecal coliform counts were determined by the Colilert® method. In total, 120 samples distributed over a period of seven weeks were analyzed; each week 3 samples were taken on Mondays, Wednesdays and Thursdays from each study point of each treatment plant. The results were statistically evaluated using two-tailed Student's t-tests using a significance level of 5%. Only incoming or raw water presented statistically significant differences in the conductivity (<0.001) and total (<0.001) measurements, which may be due to the different flow rates that feed the plants. The other stages analyzed in both physical and microbiological parameters did not present statistically significant differences, demonstrating that the treatment process of these two plants that supply the highest percentage of the population is statistically comparable.
Control microbiológico de alimentos en la vía pública en Cuenca, Ecuador
(2023) Ortiz Ulloa, Silvia Johana; León Vizñay, Jéssica Andrea; Donoso Moscoso, Silvana Patricia; Astudillo Rubio, Gabriela Cristina; Astudillo Neira, Diana Ligia de Lourdes
Street-vending trade in ready-to-eat foods has grown exponentially, worldwide. However, the lack of optimal conditions for the preparation and sale of these foods can affect their safety. The objective of this study was to evaluate the microbiological quality of 19 types of foods (n= 417), with and without heat treatment, sold in public spaces in Cuenca, Ecuador. According to the food group, mesophilic aerobes, coliforms/Escherichia coli, molds and yeasts, Staphylococcus aureus, Salmonella, Listeria spp., Clostridium perfringens, and Vibrio parahaemolyticus were examined. For microorganisms identification and counting, national regulations were applied and, in cases of absence, regulations from other countries were adopted. As a result, 55,4% of the samples were considered inadequate for consumption. S. aureus was the most prevalent presumptive pathogenic microorganism (81.7%). Non-compliance with regulations was significantly higher among foods without heat treatment (54.1%) compared to those heat treated (24%) and those that combine ingredients with and without treatment (21.9%) (p[removed]
Desarrollo de un patrón secundario en base de arroz para el análisis proximal
(Universidad de Cuenca, 2023-03-16) Deleg Juela, Juan Patricio; Mora Campoverde, Dennis Katherine; Ortiz Ulloa, Silvia Johana
Quality control in laboratories is performed to ensure that the results obtained are reliable and meet the quality standards for each analytical method. To perform quality control, primary or secondary standard substances are used. The disadvantages of primary standards are their high cost and limited accessibility, so secondary standards are developed to overcome these drawbacks. The objective of this degree work was to develop a rice-based secondary standard to serve as a reference for routine analytical runs of proximate analysis. Fifteen replicates were analyzed for each parameter, and the coefficient of variation was less than 15% in all cases. With the results obtained, Levey-Jennings plots were constructed for each parameter, which will serve as a reference for future analyses. For the interpretation of the graphs, the Westgard rules were used to evaluate systematic errors in the analytical process. Finally, an example of the application of the Levey-Jennings graphs and the Westgard rules was presented in this work, using the values of the replicates as if they were samples. On this basis, the variations observed in the ash and fat values violated the 12s rule which, being a warning rule, does not suggest the rejection of the series. On the other hand, the graphs for moisture, dry matter and protein complied with the rules, indicating that the analytical processes employed were performed with high precision.
Desarrollo de una estrategia participativa de capacitación sobre inocuidad alimentaria para vendedores ambulantes en la ciudad de Cuenca
(Universidad de Cuenca, 2025-09-03) Samaniego Loaiza, Luis Alfredo; Ortiz Ulloa, Silvia Johana
Street food vending, predominantly in developing countries, has been linked to inadequate hygiene and handling practices that contribute to the risk of contamination by pathogens and foodborne diseases. In the local context, street vending represents an accessible economic alternative to unemployment. This activity faces limitations such as the lack of basic infrastructure and knowledge of good food safety practices. In this degree project, the design and implementation of a participatory training strategy on food safety for street vendors in the city of Cuenca is proposed. The proposed strategy included an audiovisual component based on a Massive Open Online Course (MOOC), previously developed by the Department of Biosciences, University of Cuenca, and the Consortium for Food Safety in Ecuador. In addition, discussion spaces were included to share experiences and put the theoretical content into practice. This work is considered as a training pilot, which will allow to explore the acceptance of this training strategy and, in the future, to propose multidisciplinary solutions to the problem of lack of food safety in the population of street vendors for their social and economic welfare.
Determinación de Aflatoxina M1en quesillos artesanales comercializados en los mercados de la ciudad de Cuenca mediante la técnica de cromatografía líquida de alta resolución (HPLC)
(2016) Vallejos Quisigüiña, Gabriela Carolina; Uguña Rosas, María Fernanda; Ortiz Ulloa, Silvia Johana
This study was conducted in order to determine the level of aflatoxin M1 (AFLA M1) present in artisan cheeses sold in markets “9 de Octubre, 12 de April, 10 de Agosto and Feria Libre” of the City of Cuenca by the technique Liquid Chromatography High Resolution (HPLC) and their suitability with Brazilian legislation corresponding to 2.5 ug/kg of AFLA M1 in cheese. 33 samples were analyzed, where 7 samples were positive of which 4 were among the limit of detection and quantification (0.04 to 0.08 ug/kg), 3 were quantifiable, the maximum concentration of 0.83 ug/kg. The values of AFLA M1 were below the maximum limit allowed by the rules. Therefore, different samples of artisan cheeses sold in markets 9 de Octubre, 12 de April, 10 de Agosto and Feria Libre” in the city of Cuenca studied in this research could be considered fit for human consumption in terms of exposure to AFLA M1.
Determinación de carbohidratos totales en bebidas analcohólicas consumidas por adolescentes en la ciudad de Cuenca y Nabón
(2011) Capelo Armijos, Mayra Janeth; Pérez Ulloa, Mónica Elizabeth; Ortiz Ulloa, Silvia Johana
Determinación de coliformes totales y E. Coli en muestras de lechuga expendidas en cuatro mercados de la ciudad de Cuenca
(2013) Vélez Bravo, Andrea Paola; Ortega González, Johanna Elizabeth; Ortiz Ulloa, Silvia Johana; Cabrera Faicán, Sandra Paola
Worldwide, there is a trend towards an increment of consumption of fruits and vegetables, motivated by a growing concern of adopting more equilibrated diet. However their image healthy food excludes them from of all suspicion when health problems occur due to food ingestion The objective of this thesis was to determinethe presenceof total coliforms andE.coliin lettuce var. Iceberg that is expended in four markets of Cuenca city. The obtained results were an useful contribution to the Department of Hygiene and Control of Markets of the Illustrious Municipality of Cuenca. This was a longitudinal descriptive study. In total, 96 samples in duplicate were analized. and the determination of total coliforms (CT) and Escherichia coli (EC) was performed by the technique PetrifilmTM. The degree of contamination of the lettuces was tolerable because only 1% of the samples were contaminated with no acceptable levels of total coliforms (>104 UFC/g) and 6,25% with no acceptable level of E. coli (>102 UFC/g),according toInternationalStandardsCollectionMicrobiologicalFoodand AlliedMoragasPaulet al. In addition, no significant relationship was observed between the sale place (market) and the place of production with the grade of contamination of lettuces. Although a low prevalence of contamination found, , the presences of indicators of fecal contamination suggests that the lettuces might have an inadequate microbiological quality, representing a source of ETAs, if the contamination is not controlled through good practices of hygiene.
Determinación de contenido proteico de microalgas como fuentes alimentarias alternativas
(Universidad de Cuenca, 2023-10-30) Flores Vizñay, Diana Paola; Palta Jara, Cristian Andrés; Ortiz Ulloa, Silvia Johana
Uncontrolled population growth, environmental impacts, climate change and agricultural intensification have increased global food demand. This has created the need to look for food alternatives such as microalgae, which are protein sources that could improve the nutritional value of conventional foods. However, due to their complex morphological structure, it is necessary to explore methods that facilitate the rupture of their cell wall and membrane for the extraction of intracellular proteins. In the present study, two types of sample treatments were evaluated; with and without hydrolysis to achieve a destruction of the microalgal cells that allows the release of the proteins. Subsequently, the proteins were quantified by Bradford’s method and the amino acid profile was described by HPLC. The hydrolysis process significantly improved the protein extraction and the determination of the amino acid profile, since it reduced matrix interferences in the chromatograms and allowed a better quantification of each amino acid. The protein content determined was 0.89 mg/g in Chlorella vulgaris, 7.50 mg/g in Nannochloropsis sp., 50.10 mg/g in Spirulina platensis, 1.69 mg/g in a possible Hapalosiphon species. In addition, two unidentified species were analyzed and coded as MAAL 29 (1.14 mg/g) and MAAL 32 (9.49 mg/g). Spirulina platensis and MAAL 32 were the microalgae with the best protein potential to be scaled up. These results can be used to evaluate the possibility of microalgae as source of food, additives or nutritional supplements.