Physical and chemical characterization of yacon (Smallanthus sonchifolius) roots cultivated with different doses of potassium fertilization

Abstract

The already marked tendency for functional food consumption, low in calories, and with biologically active properties, has been increasing. In this scenario, yacon tuberous roots, with high levels of nutraceutical fructooligosaccharides, gain importance. However, these nutraceutical properties depend on fertilization management. Thus, our study aims to evaluate different doses of potassium fertilization on the physicochemical characteristics of yacon roots. The experimental design consisted of randomized blocks, with 4 replications and 5 treatments: four doses of potassium fertilization (50%; 100%; 150%; 200%) of the reference value, corresponding to 178.7 kg.ha-1; 357.4 kg.ha-1; 536.1 kg.ha-1; 714.8 kg.ha-1 of potassium chloride – (KCl), and a control (soil without fertilization). The chemical features evaluated were pH, total titratable acidity, soluble solids, conductivity, turbidity, moisture and ashes. The texture profile was analyzed through toughness, adhesiveness, cohesiveness, chewability index, elasticity, and gooeyness. Most of the variables were influenced by potassium soil fertilization. Only turbidity, conductivity and gumminess showed no response to the applied doses, not fitting the tested models. Potassium fertilization improved both chemical (higher levels of soluble solids and less acidity) and physical characteristics (less hardness, chewability, cohesiveness, and adhesion) of yacon tuberous roots, bringing greater quality to the final product. Highlights Yacon is considered a prebiotic food. Several immunostimulatory characteristics promote antimicrobial, anti-inflammatory, and antioxidant activity. Potassium is associated with root size, shape, texture, color, flavor, acidity, nutrient transport resistance, nutritional value, and even market value. Texture constitutes an important factor and quality criterion for the sensory acceptance of food. Thus, the results obtained show that potassium fertilization improves both physical and chemical characteristics of yacon roots. The best results were observed with the maximum dose of potassium fertilization (357.4 kg.ha-1 of KCl).

Uso potencial de dos forrajeras herbáceas (Axonopus catarinensis y Smallanthus sonchifolius) en los sistemas silvopastoriles del trópico alto colombiano

“…Al comparar diferentes profundidades de siembra (5, 10, 15 y 20 cm) en condiciones de tierras bajas en Brasil (128 m s. n. m.) y su efecto sobre la producción de tubérculos (p≤0,05), la mayor producción fue a 10 cm de profundidad (50,21 t/ha) (Lima Quaresma et al, 2020;Lima Quaresma et al, 2021). Al comparar la producción de tubérculos con la siembra de propágulos con diferente número de yemas germinativas, se encontró que la mayor producción (p≤0,05) se dio con rizóforos que contenían entre tres y cuatro yemas (Ferreira Pedrosa et al, 2020). En general, la producción total presenta variaciones de acuerdo con la zona de vida, tipos de siembra y prácticas de manejo del cultivo.…”

Correlations between physical and chemical characteristics of Cortibel guava (Psidium guajava L.) fruits grown in the Brazilian Cerrado

“…Fruits intended for processing must have high titratable acidity and soluble solid content in the pulp, while those for fresh consumption require low acidity and high soluble solids. Assessing the characterization and correlations of these attributes enables the production of high-potential fruits for both segments (5,28).…”