Lactic acid, or lactate, is naturally produced in the human body and elsewhere as a by-product of anaerobic respiration. It can be found within the human gastrointestinal system, where these bacteria could account for more than 1% of the cells in the gut. Because of the conditions in the digestive system, the bacteria respire without oxygen and produce lactate as a waste product.
Many nutritionists believe that a diet rich in foods containing lactic acid brings a variety of health benefits. Lactic acid is thought to boost the immune system, decrease the likelihood of gastro-intestinal infections and have wider beneficial effects on the body as a whole.
Lactic acid can be found in a wide variety of foods, from yoghurt to pickles. Some foods rely on lactic acid for its chemical properties, others for its taste and some for both.
Lactic acid in cheese making
Lactic acid is one of the key components of cheese making. To create cheese from milk, the casein proteins need to be encouraged to bond with one another, but they have a negatively charged outer layer. This negative charge prevents the protein cells from sticking together, but it can be neutralised using lactic acid.
Cheeses made in this way can be known as acid set, lactic set or acid coagulated. Cottage cheese, cream cheese and quark are all made using this method to separate the curds from the way. Lactic acid can also be combined with heat to achieve the separation to make other soft cheeses such as ricotta.
This lactic acid is vegan-friendly and can be used to make dairy-free cheese and butter.
Lactic acid in fermentation
As we understand more and more about the digestive system, it is becoming clear that what we eat has a considerable impact on our physical and mental health. Fermenting fruits and vegetables can increase the availability of their vitamins and minerals. This enables your body to absorb more of their goodness while also boosting the gut bacteria that manufacture B vitamins and synthesise vitamin K.
Lacto-fermentation is one way to achieve these health benefits from the foods of your choice as well as classic fermented dishes such as sauerkraut and kimchi. Lactic acid can be added to a variety of vegetables, then kept in an oxygen-free environment to allow the probiotic bacteria to develop that distinctive fermented taste.
Experts recommend eating more fermented foods in order to maintain a healthy gut biome. Fermented foods contribute to this through their probiotic effect on the lining of the gut which is a key component in maintaining a healthy immune system. There is also evidence that a healthy gut could improve mental health, so fermented food can be a great addition to a gut-friendly diet.
Lactic acid in baking
Lactic acid can be used to great effect in baking, adding a subtle but distinct flavour and also acting as a leavening agent. Louis Pasteur, who developed the process of pasteurisation, was the first to identify lactic acid as the reason that bread was rising.
Sourdough bread leavened with lactic acid has a number of beneficial qualities as a result of the fermentation process, including improved density and more balanced moisture content. Bakers that are chasing the perfect flavour and texture for their bread can use lactic acid to develop the ideal taste. It is also gluten-free, so can be used to give your baking a flavour boost even if you are using recipes suitable for coeliacs and those with gluten intolerance.
The chemical properties of lactic acid make it a great ingredient to have on hand for everything from cocktails and beer to yoghurt and buttermilk and even miso sauce and salami.