Heat and Mass Transfer During the Warm Water Blanching of Potatoes

Abstract

A model of heat and mass transfer with simultaneous chemical reaction is proposed for analyzing the influence of operating variables on the reducing sugar content at the surface of blanched potatoes. This content is partially responsible for the color of the fished product. The involved parameters (potato thermal conductivity, heat transfer coefficient of the system and kinetic constants for overall reaction of reducing sugar generation) were evaluated in separate experiments. The apparent diffusion coefficient of reducing sugars in potatoes was the only parameter obtained from blanching experiments. Temperature and concentration profiles and effect of blanching temperature on surface reducing sugar content are analyzed using the developed model. The possible underestimation of the diffusion coefficient when simultaneous starch hydrolysis is not taken into account is also considered.

Whirling bed blanching of potato cubes and its effects on product quality

“…7) clearly showed that maximum loss of reducing sugar occurred during hot water blanching at 100°C (1.00 g/100 g after 3 min) while minimum loss occurred during whirling bed blanching at 80°C (0.49 g/100 g after 3 min). The trends observed in case of hot water and steam blanching were found to be in accordance with the earlier reported works (Califano & Calvelo, 1983;Selman, 1987) which also indicated that loss of reducing sugar during blanching is a diffusion based process. However no such earlier reported work was found on whirling bed blanching.…”

“…Blanching helps to minimize reducing sugar (Califano & Calvelo, 1983). Several studies have also been conducted on loss of reducing sugar during blanching of potato (Hoover & Xander, 1963;Schwimmer et al, 1957;Shallenberger, Smith, & Treadway, 1959;Talburt & Smith, 1975).…”

“…Weaver, Reeve, and Kueneman (1975, Chapter II) and Duckworth (1979) observed that blanching reduced sugar concentration resulting in a better coloured product. Califano and Calvelo (1983) and Abdul-Rezzak (1983) studied diffusion coefficient of reducing sugar during hot water blanching of potato and found it to vary from 3.17 · 10 À10 to 16.32 · 10 À10 m 2 /s for the temperature range of 45-75°C.…”

Experimental and Theoretical Investigation of Mass Transfer during Leaching of Starch and Protein from Potato

“…The effective diffusivity values ranged from 1.070 Â 10 À10 to 1.893 Â 10 À10 (m 2 =s). These values are in agreement with the literature values for diffusivities of solutes and moisture in foodstuff (Califano and Calvelo, 1983;Doulia et al, 2000;Mujumdar, 1995;Varzakas et al, 2005;Zhao and Kjeld Porsdal, 1988;Zogzas et al, 1996).…”

Modeling of Sulfur Dioxide Uptake in Pre‐Peeled Potatoes of Different Geometrical Shapes

“…This value can also be predicted using Eq. (2) and considering that Dso, -~~0 = 1.7 X 10m9m2/ set at 25°C (Perry and Chilton, 1973), E = 0.78 (total solids content = 22%) and adopting a tortuosity factor Sz = 1.23 similar to that reported by Califano and Calvelo (1983) and obtained by Stahl and Loncin (I 979).…”