I would add an arity-3 version of collect_channel_props that takes the accumulator as the third argument.

collect_channel_props(JObj, List) ->
    collect_channel_props(JObj, List, []).

collect_channel_props(JObj, List, Acc) ->
    lists:foldl(...).

Then you can, in the internal fold, call to the arity-3 version and just return that (using Acc0 as the accumulator).