Vegan ice cream has chalky texture I made vegan ice cream for the first time. The recipe: 


350 g peeled bananas, 
frozen 100 g raspberries, 
frozen 100 g coconut cream 
50 g agave syrup


I put everything through the high speed blender, until it was finely pureed. The texture was like soft serve ice cream, and it was rather prone to quick melting. It had practically no overrun. I put it in a glass container in the freezer overnight, the way I do with churned dairy ice cream. 

Now the ice cream is somewhat difficult to break out of the container, certainly more so than churned ice cream. And it melts in the mouth to an unpleasant, chalky texture with a strong banana taste and almost no coconut flavor (the recipe was advertised as coconut-raspberry flavor). 

This is not the first time I've seen banana based vegan ice cream recipes, but it's the first time I make one. Is it normal for them to get chalky? If not, what caused it? The raspberry seeds? The frozen coconut cream? 

Also, if I want something softer, would this type of recipe be suitable for churning, and if I churn it, can I expect a creamier result?
I don't make "vegan ice cream" though I do make sorbets that happen to be vegan, most of the time. I found that coconut cream gave me strange texture issues (much harder than it should be based on sugar percentage), "light" coconut cream was better than "normal" in this regard (opposite to what I expected, but I guess it's the fat solidifying), and I think my next coconut batch will be just dried coconut, water, sugar and pectin (my not-so-secret sorbet secret.)

Other than that specific issue, the sugar content of your recipe scans low. Sugar serves an important textural role in frozen desserts, and should be approximately 30g per 100g (30% by weight) for most frozen dessert products. While you'll have some sugar in the fruit, it is not that much, and the agave syrup is partly water, so it's likely contributing only 35g or so of sugar for 50g of syrup. 

If you put bananas in any frozen dessert, they'll take over, IME, so I don't find that surprising. And coconut meat has much more coconut flavor than cream of coconut, also IME.

If you wanted coconut raspberry, I'd suggest dried coconut, raspberries (check the sugar per 100g on the package, or look up commercial ones similar to ones you've frozen at home (ie, with or without added sugar when freezing), figure how much sugar you've got from that, add a sugar source to bring it up to 30%, add pectin if you like, and freeze in whatever manner you like. You'll likely need some water, too, though it could all be done with enough raspberries providing their juice to the coconut. I find that a proper mix makes good product whether it's still-frozen or churned.