Techno-functional properties and antioxidant capacity of the concentrate and protein fractions of Leucaena spp. seeds / Propiedades tecno-funcionales y capacidad antioxidante del concentrado y fracciones proteicas de semillas de Leucaena spp

Introduction: The use of vegetable proteins as ingredients in food systems is based on their functional properties. The water and oil holding capacity, foaming, and emulsifying capacity/stability, and antioxidant assay of the protein fractions - albumins, globulins 7S/11S, glutelins and prolamins - isolated from Leucaena seed were evaluated. Objective: The objective of this study was to evaluate the functional properties and antioxidant capacity of the concentrate and protein fractions of ripe Leucaena spp. seeds. Materials and methods: Ripe Leucaena seeds were collected and evaluated in Oaxaca, Mexico (16°59'21''N 96°43'26''O) during the months of February-April 2021.The protein concentrate was isolated by isoelectric precipitation (pH=9, pH=4). The albumins, globulins, glutelins and prolamins were isolated based on their solubility properties in different extracting solutions. Results: Glutelins constituted the main protein fraction (75.88%). Prolamins were not found. The glutelins fractions showed the highest oil holding capacity (0.93±0.08 mL g-1). The albumins fraction had the highest water holding capacity (2.53±0.15 mL g-1), foaming capacity and foam stability (71.83±1.26 % and 70.00±0.00%, respectively) and antioxidant capacity (18.09±0.88%). The globulins exhibited the highest emulsifying capacity and emulsion stability (56.83±1.76% and 55.67±1.20%, respectively). Conclusions: The concentrate and protein fraction of Leucaena seeds showed different techno-functional and antioxidant properties of interest for the food industry, like those showed by other commercial vegetable proteins(AU)

Introducción: El uso de proteínas vegetales como ingredientes en sistemas alimentarios se basa en sus propiedades funcionales. Se evaluó la capacidad de retención de agua y aceite, la capacidad/estabilidad espumante y emulsionante y el ensayo antioxidante de las fracciones proteicas -albúminas, globulinas 7S/11S, glutelinas y prolaminas- aisladas de las semillas de Leucaena. Objetivo: El objetivo de este estudio fue evaluar las propiedades funcionales y la capacidad antioxidante del concentrado y las fracciones proteicas de las semillas maduras de Leucaena spp. Materiales y métodos: Las semillas maduras de Leucaena fueron recolectadas y evaluadas en Oaxaca, México (16°59'21''N 96°43'26''O) durante los meses de febrero-abril del año 2021. Se usó harina de Leucaena desgrasada para la preparación de las fracciones proteicas. El concentrado proteico se aisló por precipitación isoeléctrica (pH=9, pH=4). Las albúminas, globulinas, glutelinas y prolaminas se aislaron en función de sus propiedades de solubilidad en diferentes soluciones de extracción. Resultados: Las glutelinas constituyeron la principal fracción proteica (75,88%). No se encontraron prolaminas. La fracción de glutelinas mostró la mayor capacidad de retención de aceite (0.93±0,08 mL g-1). La fracción de albúminas presentó la mayor capacidad de retención de agua (2,53±0,15 mL g-1), capacidad espumante y estabilidad de la espuma (71,83±1,26% y 70,00±0,00%, respectivamente) y capacidad antioxidante (18,09±0,88%). Las globulinas mostraron la mayor capacidad emulsionante y estabilidad de la emulsión (56,83±1,76 y 55,67±1,20%, respectivamente). Conclusiones: El concentrado y las fracciones proteicas de las semillas de Leucaena mostraron diferentes propiedades tecno-funcionales y antioxidantes de interés para la industria alimentaria, similares a los reportados por diversas proteínas vegetales comerciales(AU)

True Density Prediction of Garlic Slices Dehydrated by Convection.

Physiochemical parameters with constant values are employed for the mass-heat transfer modeling of the air drying process. However, structural properties are not constant under drying conditions. Empirical, semi-theoretical, and theoretical models have been proposed to describe true density (ρp). These models only consider the ideal behavior and assume a linear relationship between ρp and moisture content (X); nevertheless, some materials exhibit a nonlinear behavior of ρp as a function of X with a tendency toward being concave-down. This comportment, which can be observed in garlic and carrots, has been difficult to model mathematically. This work proposes a semi-theoretical model for predicting ρp values, taking into account the concave-down comportment that occurs at the end of the drying process. The model includes the ρs dependency on external conditions (air drying temperature (Ta)), the inside temperature of the garlic slices (Ti ), and the moisture content (X) obtained from experimental data on the drying process. Calculations show that the dry solid density (ρs ) is not a linear function of Ta, X, and Ti . An empirical correlation for ρs is proposed as a function of Ti and X. The adjustment equation for Ti is proposed as a function of Ta and X. The proposed model for ρp was validated using experimental data on the sliced garlic and was compared with theoretical and empirical models that are available in the scientific literature. Deviation between the experimental and predicted data was determined. An explanation of the nonlinear behavior of ρs and ρp in the function of X, taking into account second-order phase changes, are then presented.