On ColorMatters.com there is a question about Colors for Food Products: Logos and Packaging
One paragraph quoted below:
..blue is an appetite suppressant, although only in certain
concentrations and by volume of use. But a color like Purple Martin
used in a ratio of say 15-20% of total space with a dominant color
such as Golden Wheat, add maybe a punch of Oriental Red (3-5%) and
you've roused up the greatest of appetites.
Reds, oranges, violets and
rich greens in particular are all going to accentuate hunger. Increase
the intensity using black. Most grocers have discovered that black
highlights the quality and color of produce by making the background
recede. (Shrinkwrapped packaging, produce build-ups, etc.) Best advice
take a field trip to your local grocer.
Keep in mind colors that
attract the target consumer and demographics you are trying to reach.
Young? Affluent? Gourmet?
Figure and ground
What I think is a particularly good point is the importance that background plays in addition to the foreground - in order to separate figure and ground.
But in addition to pure colors, people become familiar with colours of their favourite foods to the point that similar colours consciously or subconsciously remind them of that food - making them feel hungry. Similarly for foods you don't like! So the individual tastes are going to have an important factor for sure.
In addition to the colours the imagery is going to play an important part - red may incur hunger, but an actual picture of gorgeous food is going to do the job a whole lot more.
It's interesting searching through pictures of food for ones that are especially appealing.
for example, looking on Google images for strawberries and cream - there's a lot of red going on, but actually very few of the pictures stand head and shoulders above all the others as being attractive. Some of the reds are too pale and too bright and the fruit doesn't look real - and nor does the cream come to that.
So it's perhaps questionable as to whether a picture of food is as good in a general situation as something symbolic of a food - hinting or suggestive enough in appearance for us to conjure up whatever happens to be our ideal vision of that food without it actually having to be thrust at us with a full detail photo, which may muddy the visualization through too much detail. (Too much cream may put me off, too pale a strawberry looks unripe, too dark looks overripe or unnatural)
In reality of course, it's not just down to colour - it's how all the visuals come together to represent the whole.
A single picture of a strawberry is nice - lots of red:
Add some natural context. Introduce a different colour to add some background and differentiate figure and ground:
Make a deal out of the presentation:
Or use symbology, wording, and let the subconcsious do the visualization for you:
Pictures sources: 1 2 3 4