Henry Alexander Váquiro

This study evaluated the potential of unconventional starches extracted from Andean tubers, ulluco (Ullucus tuberosus) and cubio (Tropaeolum tuberosum), as raw materials for 3D food printing. Gels were formulated with starch concentrations of 8%, 10%, and 12% (w/v) and characterized in terms of microstructure and rheological properties. Both starches exhibited suitable printability, attributed to their pseudoplastic flow behavior. However, the hardness of the printed structures varied depending on starch type and concentration. Cubio starch showed higher hardness at both low and high concentrations (8% and 12%), whereas ulluco starch exhibited its highest hardness at the lowest concentration. Microscopic analysis revealed reticulated networks whose homogeneity was influenced by the degree of gelatinization and the starch content in the matrix. The printed gels demonstrated good resilience, variable hardness, and low crystallinity, indicating thermal-induced disruption of the native ordered structure. Rheologically, the samples showed viscoelastic behavior dominated by the elastic modulus (G’) and fitted the power-law model. These findings support the technological feasibility of ulluco and cubio starches as functional ingredients for the development of customized or functional foods through additive manufacturing technologies. Their application may foster the utilization of underused crops and contribute to the diversification of raw materials in the food industry.

Basil is a highly valued aromatic plant worldwide, and drying is one of the best ways to preserve its leaves. Through a theoretical approach, the microwave drying of basil leaves can be modeled, and the effective diffusivity can be determined. However, using a model that considers moisture diffusion in the presence of intensive microwave energy is crucial. This study proposed a theoretical model to simulate the microwave drying of basil leaves in a thin layer. The model assumed that the material is homogeneous and isotropic, with the effective diffusivity depending on the microwave power. The model was solved numerically and validated with experimental data. The study also examined the effect of the microwave power on the color and bioactive properties during drying. The drying time was reduced by 60%, by increasing the microwave power from 199 W to 622 W. The effective diffusivity was found to be directly proportional to the microwave power. Drying at low powers was found to cause basil pigment degradation. However, drying at a power of 622 W resulted in better preservation of the leaves without browning. Finally, microwave drying negatively affects the bioactive compounds, as the phenolic content and antioxidant capacity in all the powers evaluated were significantly lower than in fresh basil leaves.

Egg production is a significant source of animal protein for human consumption. Feed costs significantly impact the profitability of egg production, representing more than 70% of the variable costs. This study evaluated the effect of dietary intakes of three essential amino acids (EAAs) on the egg cost for H&N Brown second-cycle laying hens. The hens were fed for 20 weeks with 23 diets that varied in their lysine, methionine + cystine, and threonine contents. These amino acids were derived from both dietary and synthetic sources. Zootechnical results were used to calculate the feed cost per kilogram of egg (FCK), considering the cost of raw materials and the diet composition. Multivariate polynomial models and artificial neural networks (ANNs) were validated to predict FCK as a function of the EAAs and time. The EAA intakes that minimize FCK over time were optimized using the best model, a cascade-forward ANN with a softmax transfer function. The optimal scenario for FCK (0.873 USD/kg egg) at 20 weeks was achieved at 943.7 mg lysine/hen-day, 858.3 mg methionine + cystine/hen-day, and 876.8 mg threonine/hen-day. ANNs could be a valuable tool for predicting the egg cost of laying hens based on the nutritional requirements. This could help improve economic efficiency and reduce the feed costs in poultry companies.

El presente estudio valida modelos de crecimiento basados en la ecuación logística para predecir y analizar la utilización de hidrolizados de vísceras de pescado como fuente de proteína de dietas de trucha arcoíris (Oncorhynchus mykiss). Se examinan las variables zootécnicas de peso corporal, longitud total y biomasa en las fases de alevinaje y levante, durante siete meses de producción. Como tratamientos, se analizan dietas isoproteicas e isoenergéticas con un contenido de 10%, 15% y 20% de hidrolizados de vísceras, así como una dieta comercial usada como control. El modelo logístico explica más del 97% de la variación de los datos de campo, demostrando ser adecuado para evaluar la eficiencia de la utilización de vísceras hidrolizadas de pescado en cantidades de 20% de reemplazo. Se concluye que el modelo logístico desarrollado aquí es una herramienta útil para diagnosticar la efectividad de la calidad biológica de las dietas en cada una de las fases de producción de la trucha arcoíris.

This work aimed to evaluate the impact of adding two essential oils (EO) from lemongrass (LEO) and Tahiti lime (TLEO) on the physical, mechanical, and thermal properties of chitosan-based biodegradable films. Six film formulations were prepared: two controls with chitosan concentrations of 1% and 1.5% v/w, two formulations combining the two chitosan concentrations with 1% LEO v/v, and two formulations combining the two chitosan concentrations with 1% TLEO v/v. The films’ morphological, water affinity, barrier, mechanical, and thermal properties were evaluated. The films’ surface showed a heterogeneous morphology without cracks, whereas the cross-section showed a porous-like structure. Adding EO to the films promoted a 35–50% decrease in crystallinity, which was associated with an increase in the elasticity (16–35%) and a decrease in the tensile strength (9.3–29.2 MPa) and Young’s modulus (190–1555 MPa) on the films. Regarding the optical properties, the opacity of the films with TLEO increased up to 500% and 439% for chitosan concentrations of 1% and 1.5%, respectively. While the increase in opacity for the films prepared with LEO was 357% and 187%, the reduction in crystallinity also reduced the resistance of the films to thermal processes, which could be explained by the reduction in the enthalpy of fusion. The thermal degradation of the films using TLEO was higher than those where LEO was used. These results were indicative of the great potential of using TLEO and LEO in biodegradable films. Likewise, this work showed an alternative for adding value to the cultivation of Tahiti lime due to the use of its residues, which is in accordance with the circular economy model. However, it was necessary to deepen the study and the use of these essential oils in the preparation of biodegradable films.

This work aimed to evaluate the use of annealing (ANN) ulluco starch in the preparation of biodegradable films and its impact on the physicochemical properties of the materials. Three film samples (FS1, FS2, and FS3) were prepared at a fixed starch concentration (2.6% w/v) using glycerol as a plasticizer and then compared to a control sample (FSC) prepared with native ulluco starch. The physical, mechanical, and thermal properties of the films were evaluated. The use of ANN starch decreased the solubility (from 21.8% to 19.5%) and the swelling power (from 299% to 153%) of the film samples. In addition, an increase in opacity and relative crystallinity (from 7.54% to 10.5%) were observed. Regarding the thermal properties, all the samples presented high stability to degradation, with degradation temperatures above 200 °C. However, the samples showed deficiencies in their morphology, which affected the barrier properties. The use of ANN starch has some advantages over native starch in preparing films. However, more analysis is needed to improve the barrier properties of the materials. This work reveals the potential of the ANN ulluco starch for biodegradable film preparation. In addition, the use of modified ulluco starch is an alternative to add value to the crop, as well as to replace non-biodegradable materials used in the preparation of packaging.

Feijoa has a high nutraceutical and agro-industrial potential, an attractive opportunity for Colombia to enter new markets with innovative products. However, there is little knowledge about its behavior and requirements for its proper industrial processing. The studies of thermophysical and sorption properties are fundamental for analyzing and optimizing the different unit operations, evaluation, and product quality control. This study aimed to determine and mathematically model the physical, thermal, and water desorption properties of feijoa pulp in the physiological ripening stage. The desorption isotherms were determined using the gravimetric method, based on saturated salts’ solutions to create atmospheres of controlled relative humidity (RH, %), in this case, at temperatures (T) of 8°C, 23°C, and 38°C and water activities (a_w) between 0.07 and 0.98. From the isotherms model that best fits the experimental data, the isosteric heat of sorption (Q_s), differential entropy (ΔS_diff), and Gibbs free energy (ΔG) were calculated. The density (ρ), thermal conductivity (k), and specific heat capacity (cp) properties were determined and modeled at different moisture contents (H: 75%, 80%, 85%, and 90%) in the temperature range (T) 20 to 80°C, using the pycnometer method, concentric cylinder method, and differential scanning spectrophotometry (DSC), respectively. The desorption isotherms of the feijoa pulp were type III with equilibrium moisture contents (X_e) between 0.1246 and 5.5135 kg/kg (dry basis, d.b.), a monolayer moisture content of 0.2 kg/kg (d.b.); and spontaneity of the sorption phenomenon. Both cp and k depended more on H than on T; while ρ showed an equal relationship with both factors; these behaviors are characteristic of high humidity foods. The mathematical models obtained in this study are a valuable contribution for the food industry for an effective agro-industrialization, use, and added value of feijoa pulp through the design, control, and optimization of processes and equipment that involve the transfer of heat and matter. GRAPICAL ABSTRACT