I just cooked some apple bread, and I'm curious about adapting it to other fruits. I'm led to believe that the acidity of a fruit will cancel out some of the effect of baking powder or baking soda by neutralizing it, so more acidic fruits will require more baking soda to compensate. Is this accurate? If so, where can I find a comprehensive list of PHs of various ingredients, and how should I calculate how much extra baking soda to add?
Baking – How to adjust a baking recipe for fruits of different PH
aciditybakingbaking-powderfruit
Related Solutions
You cannot simply replace sugar with fresh fruit in baking recipes. Sugar is, well, 100% sugar.
Fruit is mostly water, on the order of 70-90% depending on the particular fruit in question. The remainder is usually sugars, starches and pectins for the most part.
Any recipe not specifically designed to be sweetened with fruit is going to fail spectacularly if you try to substitute. To do so, you would have to calculate the water weight in the added fruit and remove it form elsewhere in the recipe (if there is enough liquid elsewhere in the recipe to do so) at the very least.
Sugar is also extremely important to the structure and moisture retention of baked goods (with the notable exception of yeast raised breads), and simply substituting it out is going to have a deleterious effect on the texture.
Instead, you should search out recipes that are sweetened in a manner that meets whatever requirements you have. Applesauce and cooked down pears, as well as bananas might be suitable, but it would depend on the specific application.
In any case, almost no sugar will be lost during baking; all fruits will retain essentially all of their sugar.
Except at the very edge of the baked good, where browning occurs (indicating caramelization and the Maillard reaction are taking place), the sugar will be unchanged by the baking process. The amount of sugar lost to browning in the crust is vanishingly small.
See the improved answer here: What DOES Help?
Which acid works best to keep avocados from browning?
Answer: None (of the acids tested)
It's not that acid doesn't do much to help.
ALL OF THE ACIDS TESTED CAUSED AVOCADOS TO BECOME MORE BROWN AND TO BECOME BROWN FASTER THAN NO TREATMENT AT ALL
I am not kidding.
Method
For acid, I used freshly squeezed lemon juice, freshly squeezed lime juice, distilled white vinegar (diluted to 5% acidity), and Ball brand Fruit Fresh mixed per package instructions, 2 tsp powder to 3 TBS water. Fruit Fresh contains dextrose, ascorbic acid, citric acid and silicon dioxide. According to the label, 1/4 tsp of the powder contains 230% of the US RDA of Vitamin C (ascorbic acid). That roughly translates to the solution I used having 100X the concentration of Vitamin C of lemon juice. I was not able find anything to give me a basis for comparison of citric acid concentration.
I diced 1 avocado and shuffled up the chunks so that no 1 pile had chunks from only 1 part of the fruit. I dropped the chunks into small bowls of the acids, removed the chunks, and allowed to air dry. They remained at room temperature for 24 hours.
I mashed 2 avocados together and put 50 grams of the mash into each of 5 small bowls. I added 1/4 tsp of each individual acid to each bowl, leaving 1 bowl plain. I mixed thoroughly and scooped the mash onto 2 plates, 1 to be refrigerated, and 1 to be left at room temperature. I washed and dried the scoop between changes in acid.
Results
The diced avocados just gradually became darker over 24 hours, with the vinegar treated fruit the first to show signs of browning, and ultimately the vinegar treated fruit became the darkest. The untreated fruit resisted browning the longest and ultimately browned the least. The lemon juice and lime juice were about tied, they both significantly sped darkening and ultimately became significantly darker than the untreated fruit. The Fruit Fresh barely made any difference, but the slight difference there was, was negative. Fruit Fresh also caused the avocado to become darker and to brown faster, but just barely.
At 24 hours all of the mashed, unrefrigerated avocado had become equally brown and unappetizing, it just happened faster to the treated avocado. The difference was most dramatic at 6 hours:
It's not clearly visible in the photo, but the Fruit Fresh treated avocado was ever-so-slightly more brown than the untreated avocado.
At 6 hours none of the refrigerated, mashed avocado was significantly browning.
At 24 hours all of the mashed avocado was the worse for wear. On the non-refrigerated side, it looks on this photo like the vinegar treated avocado ultimately fared the best. It actually didn't. I didn't think to snap a picture, but the vinegar treated avocado was the only one to discolor all the way through. The others were still green on the inside, the vinegar treated scoop was slightly browned even on the inside.
There came a point about 12 hours in that the refrigerated side just stopped browning. It had dried out, leaving it more green than the non-refrigerated side, but no more pleasant. All of the samples browned and dried out fairly equally.
At 48 hours I had one scoop of mashed avocado left that I cared to eat.
By adding nothing, keeping it refrigerated and covered in plastic wrap clinging to the surface, so that it had no air at all, this avocado is still fresh, green and ready to eat.
I'll add lime now for flavor, and some cilantro and cumin. Pass the chips.
Note:
I am honored that this answer has been so generously received, but the fact is, it really doesn't answer the question very well. This answer shows what doesn't help. As of 1/8/15 I have added and accepted a new answer based on new experiments that show what does help, it's HERE next to the checkmark.
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Best Answer
It would be nearly impossible to gauge the effect of a different fruit on a quick bread without knowing the types and amounts of other acidic things in the recipe. Milk or buttermilk are also acidic, as are some other things you're likely to find in a quick bread batter.
Your recipe is going to be calculated to have enough leavening action for the bread, using whatever acids are initially required. Most likely this is partly the fruit and partly things like milk or buttermilk (both of which are acidic, buttermilk being more so).
Using more acidic ingredients than intended will just leave your final bread slightly more acid--probably not enough to bother you, particularly if the fruit was to your liking to start with. You may find that a more acidic batter causes the baking soda to rise faster than you want, so you should watch for that. You will not be able to make the baking soda release too much carbon dioxide by acidifying more--it'll do as much as it can then stop.
If you use less-acidic ingredients, you risk making the baking soda underperform. What I would resist doing in that instance is adding more baking soda, however. You won't increase the leavening action and you may find you introduce an unpleasant metallic taste. Better in those cases to let the batter sit just a little longer to give it more time to leaven, or add more of another acidic ingredient.
Ultimately, I'd be more concerned about the varying moisture levels in the fruits used than the acidity. Apples are relatively dry compared to, say, strawberries or blueberries, so you may find that your batter is too wet to cook properly at the time and temperature prescribed.