THE IMPACT OF HIGH-TEMPERATURE, SHORT-TIME THERMAL-TREATMENT ON TEXTURE AND WEIGHT-LOSS OF GREEN ASPARAGUS

The kinetics of the degradation of texture and loss of weight of green asparagus heated to between 100 and 130 degrees C was studied. The te xture of the asparagus was evaluated with two types of cells fitted to a universal texturometer: one cell measured resistance to cutting wit h a wire and the other was a Kramer cell. The two methods enabled dist inction between the different thermal treatments, although the Kramer cell gave information about the behaviour of parts of the spear furthe r away from the tip. The thermally induced degradation of the texture and loss of weight followed first-order kinetics. With respect to the texture, the parameters obtained with the wire cell 2.5, 5 and 7.5 cm from the tip were activation energy (E-a) = 19, 20 and 23 kcal/mol, re spectively, and those obtained with the Kramer cell were E-a = 18.3, 2 0.9 and 24 kcal/mol, depending on the section of asparagus investigate d. For loss of weight an E-a of 8.9 kcal/mol was obtained; thus, it is an important quality factor to be taken into account when optimizing the process of canning green asparagus.