jsonb_each_text(jsonb_column) ILIKE '%val%'

SELECT
  '{
   "col1": "somevalue",
   "col2": 5.5,
   "col3": 2016-01-01,
   "col4": "othervalue",
   "col5": "yet_another_value"
  }'::JSONB

create table foo as SELECT '{"col1": "somevalue", "col2": 5.5, "col3": "2016-01-01", "col4": "othervalue", "col5": "yet_another_value"}'::JSONB as bar;

create index pickfoo1 on foo ((bar #>> '{col1}'));
create index pickfoo2 on foo ((bar #>> '{col2}'));

-- Create index over lowered value:
create index pickfoo1 on foo (lower(bar #>> '{col1}'));
create index pickfoo2 on foo (lower(bar #>> '{col2}'));

-- Check that it matches:
select * from foo where lower(bar #>> '{col1}') = lower('soMEvaLUe');

select * from foo where bar #>> '{col1}' ilike '%MEvaL%';