Patamakon Phomajun and Kongkarn Kijroongrojana

pp. 617 - 631

Abstract

Water activity reduction of intermediate moisture yellowstrip trevally was studied. The optimal time
(8, 12, 16, 20 hrs.) for curing marinade was investigated. The effects of different humectants (glycerol,
sorbitol, lactitol, glucose syrup) at 50% w/w of curing ingredients were compared. Results showed that
moisture content and water activity of cured yellowstrip trevally decreased as curing time increased (p<0.05).
The curing time did not affect shear force, L a b value or acceptability scores, as evaluated by nine-point
hedonic scale (p>0.05). However, the hardness of intermediate moisture Yellowstrip trevally, determined by
texture analyzer, decreased. Hardness, shear force, L a b value of sample added with various humectants
were lower than those of the control (p<0.05), whereas shear force of lactitol-added samples were not different
from that of the control (p>0.05). The glycerol-added samples had the highest overall acceptability score and
were higher than control, whereas the glucose syrup-added samples had the lowest score. Moisture content
of the samples with the addition of various humectants was higher than that of the control (18.28 %). The
samples added with glycerol retained the highest moisture (24.94%). The adsorption isotherm studies showed
that the equilibrium moisture of sample added with glycerol was higher than that added with lactitol.

Keywords

• intermediate moisture food (IMF)
• humectants
• dried fish
• adsorption isotherm