Yogurt, milk enzymes and prebiotics

Introduction

Probiotics should not be confused with prebiotics. These substances, although resembling the name, are very different nutritional factors.

Lactic ferments are living organisms; prebiotics, on the other hand, are inanimate molecules mainly belonging to the chemical group of carbon hydrates.

The name "lactic ferments" is justifiable by the fact that these microbiological probiotic strains (which we will specify better later) multiply with great ease in milk or in the relative whey, acidifying it and giving rise to various fermented foods, of which the best known is no the other the yogurt.

Lactic and prebiotic ferments are in any case interconnected, both from a purely biological point of view and as regards the physiological, medical and nutritional aspects; later we will understand better why.

Definition

Yogurt, lactic ferments and prebiotics: what are they?

lactic ferments or probiotics

Probiotic lactic ferments are microorganisms that belong to the realm of bacteria. As anticipated in the introduction, the wording "lactic ferments" arises from the fact that these beings live and successfully replicate in milk and its serum.

The life cycle of probiotics is perpetuated above all in conditions of:

• Abundant water
• Room temperature
• neutral or mildly basic pH
• Absence or shortage of oxygen.

The metabolism of probiotics is called "lactic fermentation" because, starting with lactose (disaccharide sugar typical of milk) and in the absence of oxygen (anaerobiosis), it produces significant concentrations of lactic acid. Secondly, certain amino acids and lipid compounds are also degraded in milk, releasing other molecules.

There are various species of lactic ferments, especially belonging to the genera Lactobacillus, Bifidobacterium, Eubacterium and a few Streptococcus .

What are prebiotics?

The prebiotics are molecules of various kinds that, having reached the large intestine (colon), are metabolized by the intestinal bacterial flora favoring their metabolism and numerical growth.

These are mostly water-soluble fibers (which dissolve in water to form a gel) and carbohydrates (available and unavailable) contained in foods of vegetable origin. In fact, prebiotics can be divided into two categories:

1. Also digestible and nutritious for humans; are the carbohydrates which, not absorbed in the small intestine (for example due to an excess of food), reach the large intestine and are metabolized by bacteria
2. Not digestible and exclusively available to bacteria; are the water-soluble fibers and unavailable carbohydrates that reach the lumen of the colon.

Function

Yogurt, milk enzymes and prebiotics: what are they for?

The interest in these particular micro-organisms stems from the fact that they seem to compose a part of man's physiological intestinal bacterial flora. Recall that the normal constitution of this "symbiotic population" ensures the general and specific health status of the colon to:

• Protection against pathogenic microorganisms (barrier effect, due to biological antagonism)
• Nutrient production (especially vitamin K and certain B vitamins)
• Optimization of nutritional absorption of minerals (such as calcium)
• Production of "nutritive" molecules for the mucous cells of the large intestine (acetic, propionic and butyric acid).

Thus, the human body has every interest in keeping the population of colic bacterial flora healthy. How?

1. Feeding it, to make it multiply inside the intestinal lumen.
2. Introducing possibly other microorganisms by mouth.

We have already specified that lactic ferments are microorganisms typical of fermented milk-based derivatives, such as yogurt. This suggests that, in the diet, these foods constitute the optimal source of probiotics.

On the other hand it is not exactly so and in the paragraph dedicated to yogurt we will find out better why.

What are prebiotics for?

Considering that lactic ferments constitute a large part of the intestinal bacterial flora and that the latter feed effectively with lactose, we might be led to believe that milk sugar is an excellent prebiotic. It is not exactly so. In fact, in ordinary people lactose is mainly digested and absorbed; this means that it does not reach the intestinal bacterial flora.

On the contrary, in the so-called "intolerant", lactose arrives intact in the large intestine (due to the lack of lactase digestive enzymes), where it is processed by triggering a symptom to say the least unwanted (flatulence, diarrhea, cramps, etc.).

Unlike lactose, unavailable carbohydrates and soluble fibers (contained above all in vegetables, fruits, leguminous flesh, etc.), if taken in the right quantities, produce a "less impetuous" and therefore beneficial effect.

This is why the "selected and isolated" prebiotics:

• They are often added to probiotic foods to improve the survival of lactic ferments and provide a specific substrate for intestinal bacterial flora
• They are specific supplements to improve the trophism of the intestinal bacterial flora.

The synergistic action for health is exploited in symbiotic foods that are, by definition, products containing a mixture of probiotics and prebiotics. This category of foods maintains the same therapeutic indications as probiotics. See: inulin.

Yogurt

Classic yogurt and lactic ferments

Lactobacillus bulgaricus is, together with Streptococcus thermophilus, the typical lactic ferment of yoghurt.

These microorganisms also operate in mutual synergy with a protosimbiotic mechanism: in the early stages the Streptococcus creates the conditions for Lactobacillus to reproduce and perform the work of splitting lactose.

The microbial cultures necessary for the preparation of yogurt have an optimal development at temperatures between 42 and 43 ° C.

Benefits of Yogurt

Unfortunately, most of these lactic ferments are inactivated by the digestive processes. Despite this, the chemical and physical transformations carried out on the milk during fermentation make yogurt a precious food, with noteworthy health benefits. The lactic acid produced by these microorganisms is able, for example, to inhibit the production of putrefactive substances in the intestine by the least desirable bacteria.

Lactic acid bacteria not only produce lactic acid, but also participate in the synthesis of B vitamins (such as B12) and vitamin K. The beneficial action of lactic acid bacteria also facilitates the intestinal absorption of calcium, phosphorus and magnesium.

Yogurt is therefore a particularly useful food for the health of the entire body.

Nutritional characteristics of yogurt:

• It contains less lactose than milk and is more easily digested
• Promotes the absorption of calcium and phosphorus contained in it
• It has balancing effects on the intestinal ecosystem
• It is a versatile food, ideal as a snack or dessert after a meal.

Taking

How to manage yoghurt intake, lactic acid bacteria and prebiotics?

To supplement your diet with lactic ferments, you can consume yogurt daily or resort to much more expensive pharmaceutical preparations. In the first case it is important to always check the expiration date and, after the purchase, consume the yogurt as soon as possible. In fact, the number of live lactic ferments decreases over time, especially when the temperature is exceeded by 4 ° C. However, the same problems also affect commercial lyophilized preparations, although in a more deferred manner over time.

Consult a specialist before taking probiotic lactic acid bacteria to resolve small gastrointestinal disorders. In fact there are situations, such as the bacterial contamination syndrome of the small intestine or the irritable bowel syndrome, in which these microorganisms could have an effect contrary to what was hoped for.