Readers Ask, I Answer: Lactic Acid Fermentation
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Question: “There’s this Polish deli by my place that sells pickles in tubs. Some are regular dill pickles and others have this milky looking brine. What makes the brine white? Are they safe to eat?” -Kayla M, Brooklyn
Answer: Please tell me which deli you’re going to, because you’re looking at a tub of deliciously healthy right there.
The pickles you are describing are probably lactic acid fermented pickles and they’re perfectly safe to eat. In fact, lactic acid fermented foods may actually be beneficial to you, as they provide beneficial bacteria to your digestive tract. There’s quite a variety of foods made from the lactic acid fermentation process in addition to those deli pickles as well. Common examples include sauerkraut, kimchi, yogurt and beer.
The lactic acid fermentation process is simple in process but lengthy in words to describe. In a sentence, lactic acid fermentation is a naturally occurring anaerobic process where sugars (such as glucose) are converted into cellular energy with a waste product of lactase. Pickling foods is produced via homolactic fermentation where one molecule of glucose is converted into two molecules of lactic acid while beer is made from a slightly different process called heterolactic fermentation, where the waste products also include carbon dioxide and ethanol.
Lactic acid fermentation is one of the simplest forms of fermentation as well. In order to obtain energy from the glucose, the molecule is split into two molecules of pyruvic acid. The splitting produces two additional molecules of adenosine triphosphate (which results in instant energy) as well as two additional molecules of nicotinamide adenine dinucleotide hydride. In anaerobic conditions the pyruvate is reduced because the nicotinamide adenine dinucleotide can only be regenerated when oxygen is present. This produces the lactic acid that produces beautiful pickles, pungent kimchi and tart, creamy yogurt.
The process of making lactic acid fermented pickles are easy to do as well. Its no more difficult than combining your vegetables with some salt (to inhibit undesireable microbe and bacteria growth), keeping the air out of the pickling container and paying attention. The process can take anywhere from a few days to a month to complete, depending on the desired outcome.
Foods that have been fermented this way should be kept chilled once they are pickled. Yogurt obviously has a much shorter shelf life than pickles, but most lactic acid fermented pickles can keep for a month or two in refrigerated conditions. So feel free to tear into those deli pickles with reckless abandon.