Drying Kinetics of Noni Seeds

Wellytton Darci Quequeto,Patrícia Cardoso Silva,Fábio Adriano Santos E Silva,Lígia Campos De Moura Silva,Osvaldo Resende

doi:10.5539/jas.v11n5p250

Abstract

Noni seeds have been used for years as an important medicinal source, with wide use in the pharmaceutical and food industry. Drying is a fundamental process in the post-harvest stages, where it enables the safe storage of the product. Therefore, the present study aimed to fit different mathematical models to experimental data of drying kinetics of noni seeds, determine the effective diffusion coefficient and obtain the activation energy for the process during drying under different conditions of air temperature. The experiment used noni seeds with initial moisture content of 0.46 (decimal, d.b.) and dehydrated up to equilibrium moisture content. Drying was conducted under different controlled conditions of temperature, 40; 50; 60; 70 and 80 &ordm;C and relative humidity, 24.4; 16.0; 9.9; 5.7 and 3.3%, respectively. Eleven mathematical models were fitted to the experimental data. The parameters to evaluate the fitting of the mathematical models were mean relative error (P), mean estimated error (SE), coefficient of determination (R2), Chi-square test (c2), Akaike Information Criterion (AIC) and Schwarz&rsquo;s Bayesian Information Criterion (BIC). Considering the fitting criteria, the model Two Terms was selected to describe the drying kinetics of noni seeds. Effective diffusion coefficient ranged from 8.70 to 23.71 &times; 10-10 m2 s-1 and its relationship with drying temperature can be described by the Arrhenius equation. The activation energy for noni seeds drying was 24.20 kJ mol-1 for the studied temperature range.

Highlights

Noni (Morinda citrifolia L.) is native to southeast Asia and Australia
Commercial plantations can be found in Tahiti, Hawaii and other countries of Polynesia, where most juices commercialized worldwide are produced (Silva et al, 2012)
Noni has been traditionally used for more than 2,000 years by Polynesia and such use is attributed to the effects related to antibacterial, antioxidant, antiviral, antifungal, antitumor, analgesic, anti-inflammatory, hypotensive and immunostimulant activity (Wang et al, 2002; Costa, Oliveira, Silva, Mancini-Filho, & Lima, 2013; Lemos, Queiroz, & Figueirêdo, 2015)

Summary

Introduction

Noni (Morinda citrifolia L.) is native to southeast Asia and Australia. Commercial plantations can be found in Tahiti, Hawaii and other countries of Polynesia, where most juices commercialized worldwide are produced (Silva et al, 2012). To assess the fitting of the mathematical models to the drying data of plant products, several criteria can be used, such as the magnitudes of the mean relative error and mean estimated error, coefficient of determination, residual distribution and Chi-square test. Some of these parameters have limitations, requiring the adoption of complementary criteria in the selection of the model to emphasize and endorse the decision-making. The present study aimed to fit different mathematical models to the experimental data of drying kinetics of noni seeds, determine the effective diffusion coefficient and obtain the activation energy for the process during drying under different air temperature conditions

Drying Kinetics

Mathematical Modeling

Effective Diffusion Coefficient

Results and Discussion

Conclusions