This is normal. New foods will cause changes in poop colour and consistency. No need to treat unless baby is crying a lot. Please avoid formula milk and also packaged food like nestum. They are not as beneficial as home cooked fresh food. Give khichdi, mashed potato, sheera, upma, idli, fruits, mix green vegetables in dal rice.  Type baby food recipes 6 months india in google and you will get many options. Websites like Tarla dalal give many options