We investigated and quantified the effect of both the heating temperature and time on the properties and the diffusion of food substrates in pumpkin using a steam convection oven. In addition, we performed a sensory evaluation with "boiled and seasoned pumpkin" and found the conditions that seem to be the most delicious.
The pumpkin was cooked at three different temperatures （120, 160, 200℃） and each at three different times （10, 20, 30 minutes） along with the combination mode and 100% humidity. We carried out the texture analysis, the measurement of color tone, the concentrations of sodium ion and glucose, a sensory evaluation of the suitable hardness and deliciousness as "boiled and seasoned pumpkin" and determination of the diffusion coefficient of the sodium ion and glucose. Although the hardness significantly decreased with prolongation of the heating time, there was no influence at high temperature. In contrast, the diffusions of sodium ion and glucose significantly increased due to the heating temperature and time.
For the sensory evaluation of the samples cooked at 160℃ for 10, 20, 30 minutes, the samples heated for 10 and 20 minutes were preferred in terms of deliciousness as "boiled and seasoned pumpkin", and there was no significant difference between the 10 and 20 minutes heated samples.
The change in the mean diffusion coefficients of the sodium ion and glucose for each heating time is related to the change in the total permeation level of these substrates. These results suggested that heating in a steam convection oven at 160℃ for 10 and 20 minutes was preferred for the "boiled and seasoned pumpkin", and that the high temperature activated the diffusion of the sodium ion and glucose while maintaining its hardness.
