Effects of Drying Condition on Physico-chemical Properties of Foam-mat Dried Shrimp Powder

ABSTRACT

The effects of drying parameters on moisture content, water activity, bulk density, water binding capacity (WBC), oil absorption, and color parameters (L*,a*, b*) of foam-mat dried shrimp powders were investigated. Shrimp purees were dried as a foam mat at different drying temperatures (50ºC, 60ºC, and 70ºC) and thicknesses of the foam layer (4 and 8 mm). The experimental results showed that as the temperature increased, the moisture content, water activity, and oil absorption of the samples decreased. However, their solubility increased significantly (P ?0.05). Bulk density of shrimp powder increased with increasing the thickness of the foam layer. Increasing temperature led to increased and decreased WBC with 4 and 8 mm thickness, respectively. Furthermore, the a*, b*, and L* (at 8 mm thickness) decreased with increasing temperature; however, L* increased at 4 mm thickness. Fourier transform infrared (FTIR) spectra showed some major shifts, such as in the region of 1000–1700 cm^?1, related to C–O, C–O–C, and C–H band stretching. The differential scanning calorimetry thermograms showed a large peak with a denaturation peak around 72ºC for shrimp proteins.