Optimization of processing parameters for vacuum frying of lotus seeds using response surface methodology

In this study,response surface methodology( RSM) was used to optimize vacuum frying procession of lotus seeds.A central composite design( CCD) with three important factors of frying temperature( 85~95 ℃),frying time( 12 ~ 20 min) and vacuum degree(- 0.085 ~- 0.095 MPa),was used to study the response variables of fracturability( R₁),color change( R₂) and oil content( R₃).Frying temperature 95 ℃,frying time 12 min and vacuum degree-0.095 MPa were the optimum frying conditions.Under these conditions,fracturability,color change and oil content reached to 6572.57 g,42.80 and 9.21% respectively.In addition,compared with the atmospheric fried lotus seed,brittleness,color difference,oil content and sensory evaluation of the vacuum fried lotus seed were significantly better.Fried lotus seed starch was highly gelatinization without obvious gap through electron microscopy.But the starch granules and the larger gap inside lotus seeds could be clearly seen in atmospheric fried lotus seed.