Ingredients in Cafeteria Nipponica (Android version, too) can be combined in a number of ways. The very helpful pages on Happy Enna give a number of useful tools, such as the best combinations of ingredients for various bonuses.
However, there are a few omissions (for instance, green onions have no negative traits, but none of the suggested combinations use them), and the lists don't help much if you're early in the game and have only a few materials handy, or have run out of cherries.
This little applet attempts to maximize change in food. The "max stars" rating is optional; note that the applet cannot guess the new star rating of your food, so if that changes you'll have to change it manually. Select the ingredients you have available, then click "maximize". The applet will not attempt to use two of any ingredient. If you click "do it", it will apply those changes and try to find the next best options. The "Refresh Data" option tries to reload the page while preserving your ingredient states, which is only useful if you're editing the page to fix values.