Abstract:

In order to efficiently utilize kiwi-fruit seed resource, response surface methodology (RSM) based on a three-level three-factor Box-Behnken design of experiment was used to optimize the oil yield of kiwi-fruit seed with supercritical carbon dioxide (SC-CO2). Based on the results of previous single-factor design, the critical factors selected for this investigation were solvent flow rate, pressure and temperature. Results showed that all the parameters have significant effects on oil yield as well as the interactions between pressure and temperature. The optimum conditions are obtained as following: the partical size is 40 mesh, the extraction pressure is 31 MPa, the extraction temperature is 40 ℃, the CO2 flow is 27 kg/h and the time of extraction is 150 min. Under the above conditions, the extraction rate is 31.86%, and the fatty acid compositions of kiwi-fruit seed oils extracted with SC-CO2 are similar to those extracted with hexane. According to the analysis of variance and the validation experiment, a mathematical model was also established. This model can be used to predict the experiment results.

Key words: supercritical carbon dioxide extraction, kiwi-fruit seed oil, Box-Behnken design, mathematical model