For greater than six thousand years, mankind has been utilizing fermentation to organize meals and drinks, and nonetheless fermented dairy merchandise and different fermented meals are extensively consumed for his or her excessive dietary worth, pleasing sensory attributes and potential health-promoting properties. A few of these merchandise (reminiscent of yogurt) are produced and bought around the globe, whereas others are little recognized outdoors of 1 or just a few international locations.
Biochemists from the Institute of the Analysis Middle of Biotechnology RAS (Russia) and Durban College of Expertise (South Africa) studied the composition and properties of fermented drinks common of their international locations. The analysis included three milk-based merchandise—kefir and ryazhenka from Russia, and amasi (also called maas) from South Africa, in addition to one corn-based South African product—mahewu (also called amahewu, mageu).
“Often, meals is taken into account solely as a supply for sustenance. Nonetheless, increasingly individuals begin to consider that it additionally ought to protect and enhance well being. Trendy strategies of biochemistry, biotechnology, medication, and pharmacology permit mankind to look in another way on the usefulness of conventional, centuries-old meals. Our analysis focuses on fermented merchandise, which common consumption can doubtlessly forestall atherosclerosis, hypertension, and thrombosis,” says Konstantin Moiseenko, co-author of the research.
Kefir is comprised of milk utilizing a particular starter tradition, kefir grains, which accommodates a lot of completely different microorganisms, together with Lactococcus, Lactobacillus, and Leuconostoc micro organism, acetic acid micro organism, and yeasts. Kefir is native to the Caucasus area, however within the nineteenth and twentieth centuries, it unfold to different areas and have become probably the most common sour-milk drinks in Russia.
Ryazhenka can also be a particularly common product within the Russian market. This drink is comprised of baked milk utilizing conventional yogurt starter that features the micro organism Lactobacillus bulgaricus (Bulgarian bacillus) and Streptococcus thermophilus.
Amasi is produced in South Africa from cow’s milk utilizing bacterial cultures of Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, and Leuconostoc mesenteroides subsp. cremoris. The normal manner of creating amasi includes fermentation in a calabash or in a gourd. One other typical South African fermented delicate drink, mahewu, is comprised of cornmeal, which begins to ferment when wheat flour or lactobacillus starter is added.
The experiments and their outcomes
Scientists analyzed the content material of antioxidants and fatty acids (for fermented dairy merchandise) within the drinks, in addition to the risky natural compounds that decide their style and odor. As well as, biochemists examined which of the merchandise can inhibit the angiotensin-converting enzyme chargeable for enhance of blood strain.
Milk-based merchandise had been discovered to have extra antioxidants, however mahewu was higher at suppressing the angiotensin-converting enzyme. The composition of fatty acids in kefir and ryazhenka was extra numerous than in amasi, and from the viewpoint of a nutritious diet (prevention of atherosclerosis and thrombosis), kefir and ryazhenka are preferable. Nonetheless, extra branched chain fatty acids have been present in amasi; these fatty acids have just lately been thought-about as essential bioactive molecules which might be useful for human well being. Particularly, some research confirmed that branched chain fatty acids have anti-tumor exercise.
Kefir and ryazhenka have a extra distinct and spicy taste in comparison with amasi, which feels creamier. Mahewu has fairly plain taste however acquires extra fruity notes when saved. Acidic parts in all these drinks had been equal – a few third of all risky compounds. Kefir was discovered to have the best alcohol content material (67% of all risky compounds), whereas ryazhenka and amasi had solely three % every. Scientists discovered ketones solely in ryazhenka (62%) and kefir (1%), and esters in mahewu (50%) and ryazhenka (6%). This explains the fruity taste of the primary two merchandise and the peculiar taste of the third. Fragrant alcohol (furfural), fashioned on account of the Maillard response, was additionally discovered within the ryazhenka, which supplies the drink a burnt caramel taste. As well as, acetoin was present in amasi (which makes it creamy), and lactamide was present in mahewu (the supply of which appears to be wheat flour added throughout fermentation).
“Outcomes of our research will assist to replace and prolong present dietary advice for wholesome consuming. Learning the substances which might be chargeable for the standard style of those meals might help discover higher combos for brand spanking new recipes. There’s a speculation that meals that share risky natural compounds usually tend to style higher collectively,” defined scientists.
– This press launch was supplied by the Federal Analysis Centre «Fundamentals of Biotechnology» of the Russian Academy of Science