TEXTURAL AND SENSORY PROPERTIES OF ?-AMYLASE TREATED POI STORED AT 4C

Abstract

Poi, a purplish paste made of cooked taro (Colocasia esculenta), hardens rapidly to a rubbery gel at a refrigeration temperature of 4C. This gelling phenomenon was averted by an addition of α-amylase in poi prior to refrigeration. Two sources (porcine pancreas and Aspergillus oryzae) of the enzyme were compared at usage levels of 200 units and 2,000 units. Both the viscosity readings and textural analyses indicated that the enzymatic treated poi maintained a fresh-poi like softness. The α-amylase from porcine pancreas exhibited the least effect at the 200 unit level, while the α-amylase from Aspergillus oryzae caused a slight thinning of the starch staple. The sensory evaluation indicated that the textural attributes were in agreement with the instrumental measurements. Their flavor profiling indicated a loss of the taro taste, however, no off-flavor was observed from the enzymatic treatment at 4C for up to seven days. Le poi, une pâte violacee preparee a partir de taro cuit (Colocasia esculenta), durcit rapidement en gel caoutchouteux a une temperature refrigeree de 4°C. Ce phenomene de gelification peut etre evite par addition d'α-amylase dans le poi avant refrigeration. Deux sources de cette enzyme (pancreas porcin et Aspergillus orysae) sont comparees a des concentrations d'utilisation de 200 et 2000 unites.