Effects of environmental conditions on characteristics of annatto seed by-product

Authors

  • Bogdan Demczuk Jr,

    Corresponding author
    • Graduate Program of Food Engineering, Chemical Engineering Department, Federal University of Paraná – UFPR, Curitiba, Paraná, Brazil
    Search for more papers by this author
  • Rosemary Hoffmann Ribani

    1. Graduate Program of Food Engineering, Chemical Engineering Department, Federal University of Paraná – UFPR, Curitiba, Paraná, Brazil
    Search for more papers by this author

  • Nomenclature

    A, B, C, K, k1, k2, z= models' constants; aw = water activity; HST = isosteric heat of sorption (kJ mol−1); L*, a*, b* = color features; Meq = equilibrium moisture content (g of water g of dry matter−1); N = number of data; p = number of constants P = relative percent error (%); PTFE = polytetrafluoroethylene; R = universal constant of gases (8.314 × 10−3 kJ mol−1 K−1); R2 = coefficient of determination; SE = standard error; xm = monolayer moisture content (g of water g of dry matter−1); Y and Ŷ are the experimental equilibrium moisture content and the calculated equilibrium moisture content, respectively.

Correspondence:

Bogdan Demczuk Jr, Centro Politécnico, Jardim das Américas, Curitiba, Paraná, Brazil, P.O.Box 19011, Postal Code 81531-990. Tel: +55 41 3361 3232; Fax: +55 41 3361 3232; E-mail address: bdjunior@gmail.com

Abstract

Introduction

The processing of annatto seeds yields a low-cost by-product known as annatto seed by-product. Due to its remarkable bixin levels, which is a natural antioxidant, the annatto seed by-product could be used in animal feed supplementation. As a low-moisture product, it is important to know information about hygroscopic behavior, changes during storage, package selection and drying equipment design.

Objectives

The annatto seed by-product's hygroscopic behavior was studied at 25 °C and 35 °C by using saturated salt solutions and the static method.

Methods

During storage with different relative air humidity, the annatto seed by-product's isosteric heat of sorption, bixin content and instrumental color parameters were evaluated.

Results

The isotherms exhibited type III behavior and the Kühn model properly fitted the annatto seed by-product's equilibrium moisture data. Above 75% air relative humidity, agglomeration, darkening and fungal development were observed. The isosteric heat of sorption decreased with an increase in moisture content.

Conclusion

Once the equilibrium was established, bixin losses (approximately 43% of the content) and color changes were more prominent at 35 °C, especially under 68% relative humidity.

Ancillary