Hi Pasha,
As per your requirement we can't able remove white background,but we can change the color of background of plotArea,and general ,kindly find below attachment.
oVizFrame.setVizProperties({
legend: {
legendVisible : false
},
general:{
background :{
color : '#EFEBE2'
}
},
title: {
visible: true,
text: 'Its Pie Chart'
},
plotArea:
{
dataLabel:{
visible:true,
type :'value'
} ,
background:
{
color: '#EFEBE2',
}
},