Does anyone know how to build a formula as follows

if(a4='apple' or 'pear' or 'plum', then 'fruit' else
if(a4='carrot' or 'bean', then 'veg' else
if(a4='bun' or 'cake' or 'donut' then 'pastry' else a4)))

I have been unable to find satisfactory info re or & and as part of
functions.