Here's a good question that was sent to us on our Instagram page:
"How do probiotics survive the baking process in sourdough bread and how will they stay alive in apple cider vinegar?"
t survive the baking process. Sourdough is made with a probiotic starter that contains beneficial lactobacilli, but once you have put the raw loaves in the oven, they are sterilized, similar to pasteurizing milk.
That does not mean that the bread is not a dignified food. Before baking, the bacteria from the starter disassemble the gluten in the bread into its amino acids (for those who squeeze their pearls out over gluten).
Likewise, the bacteria produce acetic acid, propionic acid and lactic acid, all of which reduce the availability of some starches for your digestive system and thereby lower the bread's glycemic index. Finally, the bacteria facilitate the breakdown of phytic acid in the bread, releasing the nutrients of the bread for digestion.
But as far as the end product is a probiotic that promotes gut health? Nope. But it is a common misconception.
And what about ACV?
We also have to look at apple cider vinegar through the same microbiological lens. Most apple cider vinegar, in turn, is the product of a probiotic process; The bacterium works on the sugars found in apples and produces acetic acid, also called vinegar. However, most cider vinegar varieties in the shops are filtered and pasteurized ̵
This type of apple cider vinegar is still useful because taking a few tablespoons before a meal improves your post-meal blood glucose levels by a significant amount.
Things differ the unpasteurized version. It contains what ACV suppliers call "the mother," the protein strands, enzymes, and bacteria that give the product its dim look. Because the unpasteurized version contains these bacteria, it is considered by some to be probiotic, but in fact, ACV-containing bacteria have not yet survived GI transit. Nevertheless, ACV does with the mother it seems to be beneficial for existing bacteria and help in the digestion of proteins and fats (by stimulating the release of stomach acid).
This is the kind that should be kept in the refrigerator, since the low temperatures bacteria cause metabolism to stall, which is good. When kept at room temperature, the bacteria continue to grow and multiply and "consume" the entire substrate in the vinegar until they eventually run out of food and die, destroying apple cider vinegar.  If you buy a bottle of unpasteurized apple cider vinegar, store it in the refrigerator after opening.
Apple cider vinegar, omega-3 fatty acids and C3G
The truth about bread