Acessibilidade / Reportar erro

Desorption isotherms and isosteric heat of protein hydrolysate from tilapia slaughtering by-product

Isotermas de dessorção e calor isostérico do hidrolisado proteico do subproduto de abate de tilápia

Abstract

Due to the by-products generated during the processing of meat, biomolecules derived from these by-products, in the form of protein hydrolysates, have been studied for being used as raw materials to produce food. In the present study, the tilapia slaughtering by-products were hydrolyzed, under 60 oC for 2 hours, and spray-dried under 130 oC. After the drying process, equilibrium isotherms of the by-products were obtained through the dynamic method, under temperatures of 20 oC, 35 oC, and 50 oC. All the equilibrium curves presented type III behavior and in the adjustment of the empirical models, the White and Eyring model represented more properly the experimental data of equilibrium. This model presented the highest value of the determination coefficient and lower values of the Sum of the Squares of Residuals (SSR), Relative Mean Error (RME), and Akaike Information Criteria (AIC). The isosteric desorption heat, calculated by the Othmer method, varied from 2395 to 5682 kJ/kg, for equilibrium moisture contents between 0.09 and 0.30 kg/kg. The equation obtained for the calculation of the isosteric desorption heat of the tilapia by-product hydrolysate can be employed in calculations related to the modeling, simulation, optimization, and control of industrial-scale drying processes.

Keywords:
Drying; Desorption heat; Fish; Storage

HIGHLIGHTS

The White and Eyring model is suitable for predicting the desorption data of NT by-product

The energy required during the NT by-product drying was achieved by Othmer method

The results are useful for drying design, predicting energy demand and storage conditions

Instituto de Tecnologia de Alimentos - ITAL Av. Brasil, 2880, 13070-178 Campinas - SP / Brasil, Tel 55 19 3743-1762 - Campinas - SP - Brazil
E-mail: bjftsec@ital.sp.gov.br