I couldn't see the difference between location /fruits { ... } and location /fruits/ { ... } because fruits was the directory in my root directory. So, to make the thing clear:

• for directories nginx will always append the trailing / to the URL, so if we type in the browser http://localhost:8090/fruits it will be always rewritten to http://localhost:8090/fruits/, because the directory fruits exists in the root directory and nothing except fruits can be matched in that case
• for proxy passes the behavior described above doesn't apply - http://localhost:8090/fruits will not have the trailing / automatically added, so http://localhost:8090/fruitsalad will be also matched