Open AccessStudy on Drying of Black Rice (Oryza sativa L.) Grains: Physical-Chemical and Bioactive Quality
Author(s) -
Newton Carlos Santos,
W. P. Silva,
Sâmela Leal Barros,
A. J. de B. Araújo,
Josivanda Palmeira Gomes,
Raphael Lucas Jacinto Almeida,
Amanda Priscila Silva Nascimento,
Renata Duarte Almeida,
C. M. D. P. S. e Silva,
A.J.M. Queiroz,
Rossana Maria Feitosa de Figueirêdo
Publication year - 2019
Publication title -
journal of agricultural science
Language(s) - English
Resource type - Journals
eISSN - 1916-9760
pISSN - 1916-9752
DOI - 10.5539/jas.v11n9p203
Subject(s) - thermal diffusivity , chemistry , biot number , mass transfer , moisture , water content , water activity , food science , thermodynamics , chromatography , organic chemistry , physics , geotechnical engineering , engineering
The present study aimed to assess the drying kinetics of black rice and fit different mathematical models (empirical and diffusive) to the experimental data, and evaluate the effect of drying air temperature on the physical-chemical and bioactive compounds quality of black rice. Drying air temperatures ranged from 40 to 80 ºC and the drying air speed was 1.5 m/s. Physical-chemical characterization of the product was based on the following parameters: moisture, water activity, ashes, total protein content, pH, total acidity, lipids, total carbohydrates, total anthocyanins, flavonoids, total phenolic compounds and antioxidant activity. Among the empirical models, Page showed the lowest mean squared deviations (MSD) and highest coefficients of determination (R2). For the diffusion model, the values of effective mass diffusivity and convective heat transfer coefficient increased with increasing drying air temperature, and the Biot number indicated that the first-type boundary condition would also describe well the drying process. Physical-chemical parameters and bioactive compounds differed between the temperatures used, and the temperature of 60 ºC led to the best relationship between drying time and preservation of product characteristics.