For white coconut chutney (vella chammanthi) :
Instead of red chillies, add 2 green chillies and instead of tamarind paste, add a few drops of lemon juice once the chutney is done.
For green chutney :
Instead of red chillies, add 2 green chillies and 1/4 cup chopped coriander leaves (cilantro) and instead of tamarind paste, add a few drops of lemon juice once the chutney is done.