Just wondering. I sliced open a small Hass avocado which I had badly misjudged re how ripe it was. The flesh was quite firm, but I was very hungry and I didn’t want to waste this expensive fruit so I cut it into thin slices and ate it with salt, pepper and balsamic vinegar. It had little if any of the typical "creaminess’ of a regular ripe Hass avocado. Overall it was pretty stiff and tasteless. It didn’t really taste like it was oily or fatty at all.
In looking up the fat content and calories of these little devils it’s pretty staggering at 50 cals per oz or 250 calories for a small 5 oz avocado. Were there as many available fat calories in that very firm, non-ripe avocado as in the fully ripened ones?
I have often wondered this same thing. I know things will taste sweeter when ripe. My guess is that carbon continues to bond with hydrogen as something ripens creating more calories.
I can’t see how you get more calories as a fruit ripens, unless it is still on the plant and thus growing. The sweeter taste is because starches break down into sugars, and as far as your body is concerned, they are the same after digestion (starch is a form of polymerized glucose, the other being indigestible cellulose, which I don’t think breaks down in ripening fruit). Maybe a bit more digestive effort is needed to break down starches but the difference probably isn’t significant as they are easily broken down.
Starches (carbs) and sugar (which are more carbs) have the same calories per gram. Since it’s starches turning into sugars, not sugars turning into fats, I think it’s safe to say that an unripe fruit has about the same number of calories as the ripe fruit. “About” because some energy is undoubtedly used in the chemical reactions which convert starch to sugar, but I’m not sure that amount is measurable in our culinary “Calories”. The 7th grade science fair way to determine this, of course, would be to put an unripe banana in a sealed box and weigh it before and after ripening. Any grams lost are calories lost, if you’ve captured all the water and gasses the fruit may give off during ripening.
Avocados, I’m not so sure about. They don’t ripen by converting starches to sugars (much), they ripen when enzymes begin to break down their cell walls. I don’t have a clue how much energy this takes.
If your box is sealed well, then the box will weigh the same before and after ripening. If it’s not sealed well, then you’re not studying the avocado, you’re studying the box.
It would be theoretically possible for the Calorie count to increase after picking, if the fruit itself is still photosynthesizing. But while this isn’t completely impossible, I would expect it to be utterly insignificant.
On a more practical level, even if the total amount of Calories doesn’t increase, you might see some molecules that are too large to be used efficiently by the body (and which would ordinarily just pass through as fiber) get broken down into smaller, digestible, molecules. In that way, the available Calories might increase.
How so, if, as hypothesized, energy stored in the fruit is used in the conversion of starch to sugar? Won’t it be lighter by that matter>energy conversion? I mean, probably not measurable to a 7th grader’s scale, but in theory.
I mean, I believe you, 'cause I’m only a dabbler in science, but I’m trying to see what I’m missing.
Well, that gets back to the question of how well-sealed the box is. If it’s sealed well enough to contain the resulting heat, too, then it’ll still weigh the same, and if it lets the heat leak out, then it’ll weigh ever-so-slightly less. Of course, no real box is going to be that well-sealed, but it’s moot, since no real scale is going to be able to measure the weight difference, either.