Estimation of the effective diffusion coefficient of water in skim milk during single-drop drying
Artikel i vetenskaplig tidskrift, 2015

This paper presents a new approach combining experimental methodology and modelling, developed to evaluate the effective diffusivity of water in skim milk during drying over a full range of water contents and temperatures. This parameter is important to support modelling of spray-drying processes and designing of equipment. The effective diffusion coefficient is evaluated using a combination of nuclear magnetic resonance (NMR) and parameter estimation. NMR is used to determine the temperature dependence and parameter estimation is used to estimate the water concentration dependence of the effective diffusivity of water in skim milk (0.90 on total weight basis) during drying by comparing the experimental data obtained using a suspended-drop method, which allows the recording of weight and temperature changes during drying, with the results of a distributed heat and mass transport model. The results indicate that the free-volume theory best predicts the dependence of the effective diffusion coefficient of water in skim milk. A mathematical correlation of effective diffusivity over a full range of water contents and temperatures (from 50 to 90 degrees C) was obtained and experimentally successfully validated for concentrated skim milk (0.70 on total weight basis).

Skim milk

NMR

Single drop

Spray drying

Parameter estimation

Diffusion coefficient

Författare

Loredana Malafronte

Chalmers, Kemi och kemiteknik, Kemiteknik, Kemisk miljövetenskap

Lilia Ahrné

SIK – Institutet för Livsmedel och Bioteknik AB

E. Kaunisto

SIK – Institutet för Livsmedel och Bioteknik AB

F. Innings

Tetra Pak

Anders Rasmuson

Chalmers, Kemi och kemiteknik, Kemiteknik, Kemisk miljövetenskap

Journal of Food Engineering

0260-8774 (ISSN)

Vol. 147 C 111-119

Ämneskategorier

Kemiteknik

DOI

10.1016/j.jfoodeng.2014.09.032

Mer information

Senast uppdaterat

2018-08-24