Desenvolvimento e caracterização de farinha de hibisco para aplicação em biscoitos: cinética de secagem, composição nutricional e propriedades tecnológicas

Abstract

This work aimed to develop and characterize Hibiscus rosa-sinensis flour for use in biscuits, evaluating the impact of drying conditions on the preservation of bioactive compounds and technological properties. The drying kinetics of the flowers were performed at three temperatures (40 ºC, 60 ºC and 80 ºC), with the temperature of 60 ºC being selected as the optimal condition for balancing energy efficiency and preservation of bioactive compounds. The Lewis model adequately described the drying kinetics, with R² values greater than 0.95. The activation energy calculated by the Arrhenius equation was 27.1 kJ·mol⁻¹. The physicochemical characterization of the flour revealed significant levels of minerals, especially potassium (1.70%), zinc (25.19 mg·kg⁻¹) and copper (18.90 mg·kg⁻¹), as well as phenolic compounds (123.26 μg/mL) and flavonoids (10.37 mg QE/g sample), highlighting its potential as a functional ingredient. Two biscuit formulations were developed: a control (without hibiscus) and an experimental one (with 30% replacement of wheat flour with hibiscus flour). The physicochemical aspects showed that the addition of hibiscus flour promoted an increase in fiber and mineral content, in addition to reducing water activity, contributing to greater product stability. Sensory analysis with 100 tasters showed good acceptability, with no significant differences between the formulations (p > 0.05). Purchase intention was 80% for the hibiscus biscuit and 68% for the control. Microbiological analyses indicate good hygienic and sanitary conditions, with an absence of total coliforms and E. coli. The results demonstrate the technological viability of hibiscus flour as a functional ingredient in bakery products, adding nutritional value without compromising sensory acceptability, showing promise for innovative and healthy food applications.