Air drying modelling of Mastocarpus stellatus seaweed a source of hybrid carrageenan

作者：Arufe Santiago; Torres Maria D; Chenlo Francisco; Moreira Ramon^*

来源：Heat and Mass Transfer, 2018, 54(1): 177-184.

DOI：10.1007/s00231-017-2117-1

• Equilibrium moisture content
• Page model
• Water activity, water diffusion, algae

Water sorption isotherms from 5 up to 65 A degrees C and air drying kinetics at 35, 45 and 55 A degrees C of Mastocarpus stellatus seaweed were determined. Experimental sorption data were modelled using BET and Oswin models. A four-parameter model, based on Oswin model, was proposed to estimate equilibrium moisture content as function of water activity and temperature simultaneously. Drying experiments showed that water removal rate increased significantly with temperature from 35 to 45 A degrees C, but at higher temperatures drying rate remained constant. Some chemical modifications of the hybrid carrageenans present in the seaweed can be responsible of this unexpected thermal trend. Experimental drying data were modelled using two-parameter Page model (n, k). Page parameter n was constant (1.31 +/- 0.10) at tested temperatures, but k varied significantly with drying temperature (from 18.5 +/- 0.2 10(-3) min(-n) at 35 A degrees C up to 28.4 +/- 0.8 10(-3) min(-n) at 45 and 55 A degrees C). Drying experiments allowed the determination of the critical moisture content of seaweed (0.87 +/- 0.06 kg water (kg d.b.)(-1)). A diffusional model considering slab geometry was employed to determine the effective diffusion coefficient of water during the falling rate period at different temperatures.

• 出版日期2018-1