April 4, 2009 - 8:19am
Organic Lemon Juice in lieu of Ascorbic Acid (Vitamin C)
Commercially produced sourdough contains vitamin C as an additive to improve leavening action. I've been thinking about using fresh organic lemon juice as an alternative and wondering whether anyone has tried this yet?
+Wild-Yeast
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First, let me say that I have not tried lemon juice in dough, so can't speak with any authority on using it as an additive. But, I did look it up in The Corinne T. Netzer Encyclopedia of Food Values, which says that 1 fluid oz. of fresh lemon juice has 14 mg of vitamin C. That's not much for this application when, I think that there is around 500 mg in 1/8 tsp of ascorbic acid powder (that is, if the powder is pure ascorbic acid). Given that you'd have to use a fair amount to get enough vit C, lemon juice would contribute too much flavor and other acids as well. -dw
P.S. Orange juice has only slightly more vit C at 93 mg per 6 fluid oz. (15.5/oz.), but it's not nearly as sour.
Baked two small batards this afternoon with the juice of one Meyer lemon substituted for vitamin C. The dough was quite tasty.
The raising dough popped the lid off the plastic container in the refrigerator (Enhanced leavening action under low temperature conditions?). Oven spring is a tad better than normal. Have to wait till tomorrow for a taste comparison.
+Wild-Yeast
Sounds like the dough enhancing effect of citric acid. I did a quick search and was surprised to find that lemons have about 100x more citric acid than ascorbic:
According to Wickipedia, "lemon juice is about 5% (approximately 0.3 mole per liter) citric acid." Zing! No wonder lemons are so sour. But I think that Meyer lemons are milder than regular lemons, no? They probably don't have quite as much.
Acids in general have a protein/gluten tightening effect, and citric acid is used in commercial dough enhancers such as Blue Chip, and this one by Kitchen Resource:
Here's another little document that popped up on other uses for citric acid around the house, from cleaning to improving homemade playdough :-)
Click here: http://mikewye.co.uk/K-Citric%20Acid%20950.pdf
dw
Protein Relaxation Effect
Yes, I've been wondering about the tradeoff between ascorbic vs. citric acid. Having read that the acid in lemon juice would have a relaxing effect on the proteins I was somewhat concerned whether this would make the dough too slack. This was not a problem as it turned out.
Meyer Lemons
Meyer Lemons are sweet enough that some people eat them like an orange. Alice Waters put Meyer Lemons on the map in the California Cuisine movement but ancient Californio's have known about them for a long time (the only true Ceasar Salad uses Meyer Lemons). Some say they're a cross between a true lemon and a mandarin orange but this is still only conjecture though they do taste that way and are definitely higher in sugar content.
Effect on Retarded Sourdough a Surprise
The cold fermentation action turned out to be the real surprise of this experiment. Now to look for referrences on the effect of citric acid on retarded natural sourdough fermentation. One other point that should be mentioned, I use a wisk attachment in the early stages of mixing the dough creating a smooth, aerated batter of starter, flour, water, salt and lemon juice. This is followed by mixing in more flour with a dough hook till the dough exhibits the correct hydration. As I foggily remember this should be a fairly good preparation for setting up a Krebs Cycle environment for yeast production. . . ,
+Wild-Yeast
No doubt you have a combination of effects going on here, not necessariily limited just to oxygenation, and ascorbic and citric acids. Who knows what other beneficial substances may be in play, or what sort of synergy they all may have.
Acids and Proteins
Acid by itself actually tightens gluten (and proteins in general), increasing elasticity. I think that the gluten relaxing effect is indirect, in that proteolytic enzymes are more active in an acid environment. If you're using a white flour that is relatively low in these enzymes, then the dough isn't as likely to go slack than if you're using a flour that hasn't had these stripped away. If you tried this on a 100% whole grain sourdough, the result might be very different.
Oxygenation
The Krebs Cycle converts all 6 of the carbons in a sugar molecule into CO2, whereas only 2 become CO2 during alcohol fermentation. (Because the remaining 4 are turned into two molecules of ethanol.) So more oxygen in the dough means more CO2 and more lift. Also, more oxygen (intensive mixing) develops the dough faster. Oxidation has a significant effect on gluten development and elasticity.
Citric Acid and Sourdough
Citric acid is one of the co-substrates that can be used by heterofermentive LAB to produce acetic acid from sugar. I have also seen another side pathway that converts citric acid into acetic, but I don't completely understand it. What I do understand is that citric acid increases acetic acid production, and I believe this is sometimes why it is added to commercial sourdough. Since citric is converted into acetic, or into something else when acetic is produced, it increases acetic acid without influencing the total acid or pH (well, beyond the initial impact anyway).
So now the questions: How did the bread turn out? Is it any more sour than usual? Can you taste the lemon? What's the overall verdict? Inquiring minds want to know :-)
dw
Crust
Turned out to be somewhat more chewy than normal. Browning and coloration normal.
Crumb
Higher amount of fermentation bubbles than normal. Not as chewy as normal more cake like. Somewhat on the dry side.
Taste
Slightly more sour than usual. Only the very slightest hint of lemon.
Aroma
Almost a hint of lemon but it's probably just imagination. The sourdough aroma is still dominant along with the roasted walnut aroma of the caramelized crust.
Summary
A very nice looking loaf, crust and crumb. The drier more cake like crumb was not up to expectations though. A nice experiment but I don't think it warrants further investigation as no marked taste improvement resulted.
Millennia of the sourdough tradition may be giving a hint here. . . ,
+Wild-Yeast
hi i read somewhere that if you add a teaspoon of lemon juice to your bread it turns out more lighter. haven't tried this yet myself.
It certainly sounds like it came out a bit lighter.
Thank you for sharing your results. I can appreciate a good experiment---whether the results are good, bad, or indifferent, they can often teach us something more valuable than the small cost of the flour :-)
dw