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This is a common question which is asked by those of us with lactose intolerance. If you have trouble digesting lactose then eating fermented milk products is a great option but if you are seriously lactose intolerant then any dairy products are out of the question. All dairy products contain lactose. Yes, some which are chemically treated with an enzyme called lactase, contain less lactose and in some cases only trace amounts but it is still present.
Dairy yogurt cannot be made lactose free, there will always be trace amounts of lactose in dairy yogurt, even with long incubation times. A lactose free yogurt like product can be made with non-dairy milks which contain live lactic acid bacteria providing similar benefits of dairy yogurt.
There are lots of recipes online for yogurt purporting to be lactose free but in reality only reduce the amount of lactose in the yogurt. To remove all the lactose from milk through the action of lactic acid bacteria would take an extended incubation period and produce a very sour yogurt. This is because the presence of lactose (the disaccharide found in milk) provides energy which the lactic acid bacteria uses to produce lactic acid, which gives the yogurt its tart flavor.
As the yogurt is incubated the amount of lactose decreases. This does two things:
- It produces more lactic acid
- It makes the yogurt less sweet
If the milk was incubated until all the lactose was removed the yogurt would become inedible. The amount of lactic acid in the milk and lack of sweetener makes it unpleasant to consume.
If you are extremely sensitive to lactose then there are yogurt substitutes which can have the same texture as yogurt which make good toppings for fruit, can be made into dips and used in shakes. They will not have the same flavor and characteristics as traditional yogurt but they can be used to replace yogurt in a number of situations.
Can homemade yogurt be made with lactose free milk?
It can be a bit confusing to some when they learn the name of the bacteria species which produces yogurt thinking that lactic acid is somehow related to the lactose in the milk. Actually lactic acid bacteria grow in all sorts of environments and can utilize all three monosaccharides in its respiration. It is the bacteria which produces sauerkraut, pickles and sourdough bread, all of which do not contain lactose.
Lactose is a disaccharide made up of two sugars glucose and galactose. To break the bond between these two sugars an enzyme called lactase is needed. When the enzyme is exposed to lactose it reacts and separates the two molecules into its two component parts. These sugars can then be used by the lactic acid bacteria in their respiration.
Lactose free milk can be used to make homemade yogurt. Lactic acid bacteria don’t use the lactose directly in their respiration, rather they use the two sugars glucose and galactose to produce lactic acid which acidifies the milk producing yogurt.
There is no usable energy released when the enzyme lactase is used to split the lactose molecule into its two separate sugars and therefore provides no benefit to the lactic acid bacteria themselves besides making the sugars available. Once the sugars are available they are used for growth and as a byproduct they produce lactic acid. When using lactose free milk this process of splitting the lactose molecule has been done already making the sugars immediately available.
How do they make yogurt lactose free?
There are two types of lactose free yogurt which are on the market:
- Milk yogurt
This is a good option if you are after the same flavor and texture of normal yogurt. There will still be some lactose in the yogurt even if it is only trace amounts so be aware that this type of yogurt is only for those who find lactose bothersome.
Commercial lactose free yogurt is made by adding lactase to milk during pasteurization. Lactase has an effective temperature range of 118-124℉(48-51℃) separates the lactose into glucose and galactose, reducing the lactose in the milk. Next the starter is added and incubated until the milk gels.
- Dairy free yogurt
If you are hyper-sensitive to lactose then there are few choices for you to have yogurt. Lactose free yogurt is made using non-dairy milks such as coconut, cashew and almond milk. All of which are not really yogurt but have a yogurt-like consistency. They all have the flavor of the base ingredient which does not work for all recipes using yogurt.
Dairy free yogurt is made by soaking and blending the nut or seed which the yogurt is to be made from, adjusting the fat, water, sugar and protein levels and incubating it with a non-dairy lactic acid bacterial starter.
Both of these methods are not ideal as the first one produces yogurt with trace amounts of lactose still in the yogurt. It is great for those who are not hyper-sensitive to lactose and still want to add yogurt to their diet. Non-dairy yogurt produces a yogurt-like product which has the same consistency and texture of yogurt (or as close as possible) but has radically different flavor.
Is Greek yogurt lactose-free
Greek yogurt has a thick creamy texture and a slightly tangier flavor which some people really enjoy. It makes great dips, toppings and is also wonderful eaten with a spoon. Unfortunately the idea that it is lactose-free is totally wrong.
Greek yogurt is not lactose free as it is made using the same process as normal yogurt with one added step. Once the milk has thickened some of the whey (the watery part of yogurt) is drained out, thickening the yogurt. This process does reduce the lactose but doesn’t eliminate it.
The lactic acid bacteria in greek yogurt starter does have a different makeup than other starters but then so does belgian, icelandic and for that matter any other yogurt from around the world. This doesn’t mean that it has more or less lactose in it. The main difference in lactose content is how much the milk had to start with, how long and at what temperature it was incubated and the amount of starter. If you want to know the effects of these variables check out this article.
Does lactose break down with heat?
In your search for options to lower the lactose in yogurt heat is a natural thought, since heat destroys enzymes and vitamins, breaks down proteins and releases and alters some fats it seems like an obvious question.
Lactose begins to breakdown at 300℉(150℃), a temperature which is unattainable for making yogurt. A pressure cooker would be needed to reach this temperature without boiling off all the liquid and using a pressure cooker would destroy all the benefits of the yogurt.
Long chain carbohydrates can be broken down by heat. This is one of the methods of extracting sugar from barley or other grains in making alcohol (beer and hard liquor). These long chain carbohydrates can only be broken down so far without high heat. In milk this would destroy all the protein and fat in the milk making it unusable for yogurt making.