{"id":10043,"date":"2021-10-28T15:39:40","date_gmt":"2021-10-28T13:39:40","guid":{"rendered":"https:\/\/ingredients.saccosystem.com\/fermentation-what-it-is-what-types-exist-and-what-are-fermented-milks-kefir\/"},"modified":"2024-04-18T17:59:30","modified_gmt":"2024-04-18T15:59:30","slug":"fermentation-what-it-is-what-types-exist-and-what-are-fermented-milks-kefir","status":"publish","type":"post","link":"https:\/\/ingredients.saccosystem.com\/en\/fermentation-what-it-is-what-types-exist-and-what-are-fermented-milks-kefir\/","title":{"rendered":"Fermentation: what it is, what types exist and what are fermented milks (Kefir)"},"content":{"rendered":"&#13;\n<p>For the past few weeks, an old acquaintance has reappeared in my house. I haven&#8217;t seen<strong> kefir<\/strong> in years, so much so that I associate it with my teenage days. I still remember when this<strong> fermented milk<\/strong> first entered our house, received as a most precious gift from a family friend, with a thousand recommendations on how to take care of this &#8216;baby&#8217; with almost magical characteristics.<\/p>&#13;\n\r\n<div class=\"wp-block-spacer\" style=\"height: 30px;\" aria-hidden=\"true\">\u00a0<\/div>\r\n&#13;\n<h3 class=\"wp-block-heading\">ARTICLE INDEX<\/h3>&#13;\n&#13;\n<ul class=\"has-background wp-block-list\" style=\"background-color: #fff6cc;\">&#13;\n<li><a href=\"#fermentazione\">What is fermentation?<\/a><\/li>&#13;\n<li><a href=\"#tipi-di-fermentazione\">The different types of fermentation<\/a><\/li>&#13;\n<li><a href=\"https:\/\/ingredients.saccosystem.com\/en\/fermentation-what-it-is-what-types-exist-and-what-are-fermented-milks-kefir\/#kefir\">Kefir: what is it and how is it produced?<\/a><\/li>&#13;\n<li><a href=\"#prodotti\">Fermented milk products<\/a><\/li>&#13;\n<li><a href=\"#fonti\">Sources and notes<\/a><\/li>&#13;\n<\/ul>&#13;\n\r\n<div class=\"wp-block-spacer\" style=\"height: 30px;\" aria-hidden=\"true\">\u00a0<\/div>\r\n\r\n<div class=\"wp-block-spacer\" style=\"height: 30px;\" aria-hidden=\"true\">\u00a0<\/div>\r\n&#13;\n<h2 class=\"wp-block-heading\" id=\"fermentazione\">What is fermentation?<\/h2>&#13;\n&#13;\n<p class=\"has-text-align-left\">But let&#8217;s take a step back and see <strong>what fermentation is<\/strong>, on a biochemical level.<\/p>&#13;\n&#13;\n<p class=\"has-text-align-left\"><strong>Fermentation is a metabolic pathway<\/strong>, i.e., a sequence of chemical reactions occurring in a cell to derive energy from organic compounds such as <strong>sugars<\/strong> or <strong>amino acids<\/strong>, in the <strong>absence of oxygen<\/strong>. Under aerobic conditions, i.e., when there is oxygen available, the cell prefers to do cellular respiration, which is a metabolic process that goes so far as to completely burn fuel, e.g., sugar, to the point of producing carbon dioxide and water as in all combustion. This combustion, which fortunately does not generate flames or too much heat, is very efficient in producing usable energy from the cell.<\/p>&#13;\n&#13;\n<p class=\"has-text-align-left\"><strong>However, when oxygen<\/strong> is in short supply or absent altogether, the cell, which must still produce energy, begins <strong>fermentation<\/strong>. Instead of completely burning its fuel, it only partially oxidizes it. It does not produce much energy, but it is better than nothing. The compounds that are generated by this metabolic pathway are <strong>alcohols <\/strong>or <strong>acids<\/strong> that impart <strong>characteristic aromas<\/strong> to fermented products (some pleasant, some unpleasant).<\/p>&#13;\n&#13;\n<p class=\"has-text-align-left\">A totally oxygen-free environment is often not necessary to persuade cells to ferment. <strong> Brewer&#8217;s yeast<\/strong>, for example, when put in front of a sugar-rich feast, gets excited and starts fermenting spontaneously, even though it has oxygen available for respiration. <strong>[1]<\/strong><\/p>&#13;\n\r\n<div class=\"wp-block-spacer\" style=\"height: 30px;\" aria-hidden=\"true\">\u00a0<\/div>\r\n&#13;\n<h2 class=\"wp-block-heading\" id=\"tipi-di-fermentazione\">The different types of fermentation<\/h2>&#13;\n&#13;\n<p>There are<strong> different types of fermentation<\/strong>. A well-known one is the <strong>alcoholic<\/strong> one, which is carried out mainly by yeasts and is used in the production of beer, wine, and leavened baked goods. Its characteristic is to<strong> produce alcohol and carbon dioxide<\/strong>. In some cases, we seek the production of alcohol (ethanol, also known as ethyl alcohol) to make drinks such as <strong>wine<\/strong> alcoholic. In other cases we look instead for the production of carbon dioxide, which swells <strong>bread<\/strong> and <strong>pizza<\/strong> dough (ethanol is still produced, but it evaporates during baking at high temperatures). Sometimes both are welcome, as with <strong>beer<\/strong> or <strong>sparkling wines<\/strong>.<\/p>&#13;\n&#13;\n<p><strong>Another popular fermentation is lactic fermentation<\/strong>, carried out mainly by <strong>lactobacilli<\/strong>. These bacteria convert sugars into lactic acid, which turns <strong>yogurt<\/strong> or<strong> kefir<\/strong> slightly acidic. Other substances produced or released during fermentation then contribute the distinctive aromas that make each type of <strong>fermented milk<\/strong> unique, differentiating yogurt from kefir or<strong> buttermilk <\/strong>from <strong>yakult<\/strong>.<\/p>&#13;\n&#13;\n<p>A curiosity: <strong>our muscles <\/strong>are <strong>also <\/strong>capable of<strong> lactic fermentation<\/strong>; we become aware of this when we exert too much or too prolonged muscle effort and begin to feel a sense of soreness that can last for several days and be very uncomfortable. Why does this happen. <strong>If the oxygen supply to the muscle is not sufficient<\/strong> to do enough cellular respiration to sustain the required workload, the muscle cell must still take energy for the contraction\/relaxation cycle. Guess where he gets it from? That&#8217;s right, just from lactic fermentation. It does not produce as <em>much<\/em> energy as it could have if it did only cellular respiration, but if oxygen is in short supply this is as much as it can afford. In short, it manages to keep us running a little longer, whether we are running from a bear or late to catch a train, but with the knowledge that the next day we will discount our impromptu sprint with pain and discomfort.<\/p>&#13;\n<p><img fetchpriority=\"high\" decoding=\"async\" class=\"alignnone size-full wp-image-11541\" src=\"https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/non-e-molto-ma-e-un-lavoro-onesto-1024x681-1.jpg\" alt=\"fermentation as a source of energy\" width=\"1024\" height=\"681\" title=\"\" srcset=\"https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/non-e-molto-ma-e-un-lavoro-onesto-1024x681-1.jpg 1024w, https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/non-e-molto-ma-e-un-lavoro-onesto-1024x681-1-300x200.jpg 300w, https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/non-e-molto-ma-e-un-lavoro-onesto-1024x681-1-768x511.jpg 768w, https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/non-e-molto-ma-e-un-lavoro-onesto-1024x681-1-600x399.jpg 600w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/p>&#13;\n\r\n<div class=\"wp-block-spacer\" style=\"height: 30px;\" aria-hidden=\"true\">\u00a0<\/div>\r\n&#13;\n<h2 class=\"wp-block-heading\" id=\"kefir\">Kefir: what is it and how is it produced?<\/h2>&#13;\n&#13;\n<p><strong>Kefir<\/strong> is a fermented milk whose consumption is common in<strong>Eastern Europe <\/strong>and parts of<strong>Asia<\/strong>. It is <strong><em>similar to<\/em> yogurt <\/strong>but you cannot call it yogurt, which must be produced using two particular lactic acid bacteria, as we explained in <strong>\n  <a href=\"https:\/\/ingredients.saccosystem.com\/en\/yogurt-what-it-is-how-it-is-produced-and-the-benefits-to-the-body\/\">this article<\/a>\n<\/strong>.<\/p>&#13;\n&#13;\n<p><strong>Kefir is produced from gra<\/strong> ins (or granules) that look similar to the small inflorescences of cauliflower, called <em>\n  <strong>kefiran<\/strong>\n<\/em>. These soft, gelatinous clusters are actually mini-hotels for microorganisms, harboring a huge variety of microbial species. Studies on this microbial consortium began in the 1970s, and even today new information is being discovered about the tiny inhabitants of these miniature cauliflowers.  <strong>[2]<\/strong><\/p>&#13;\n&#13;\n<p>Interestingly, it turns out that it is not only <strong>bacteria<\/strong> that live inside kefir granules, but there are also <strong>yeasts<\/strong>. Their presence makes the<strong> fermentation of kefir<\/strong> different from that of plain yogurt. <strong>[3]<\/strong><\/p>&#13;\n<p><img decoding=\"async\" class=\"alignnone wp-image-11545 size-full\" src=\"https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/Kefir-1024x674-1.jpg\" alt=\"kefir granule contains bacteria and yeast\" width=\"1024\" height=\"674\" title=\"\" srcset=\"https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/Kefir-1024x674-1.jpg 1024w, https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/Kefir-1024x674-1-300x197.jpg 300w, https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/Kefir-1024x674-1-768x506.jpg 768w, https:\/\/ingredients.saccosystem.com\/wp-content\/uploads\/2021\/10\/Kefir-1024x674-1-600x395.jpg 600w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/p>&#13;\n\r\n<div class=\"wp-block-spacer\" style=\"height: 30px;\" aria-hidden=\"true\">\u00a0<\/div>\r\n&#13;\n<h2 class=\"wp-block-heading\" id=\"prodotti\">Fermented milk products<\/h2>&#13;\n&#13;\n<p>There are<strong> many different types of fermented milk products<\/strong> in the world. In many cases these are domestic, not industrial productions. Fermenting microbial communities, therefore, vary greatly and differ because of the <strong>microbiota typical of that region<\/strong> of the world, environmental characteristics, and the <strong>fermentation process<\/strong> used.<\/p>&#13;\n&#13;\n<p>For example, the  <em>\n  <strong>buttermilk<\/strong>\n<\/em>, o  <strong>buttermilk<\/strong>, comes from the processing of cream into butter and is fermented by <em>Lactococcus lactis<\/em> or <em>Lactobacillus bulgaricus. <strong>[4]<\/strong><\/em> In contrast, <strong>kefir<\/strong> contains a very large variety of lactic acid bacteria (83-90% of the total microbial count) such as <em>Lactococcus lactis <\/em>subsp. <em> lactis<\/em>, <em>Streptococcus thermophilus<\/em>, <em>Lactobacillus delbrueckii <\/em>subsp. <em> bulgaricus<\/em>, <em>Lactobacillus helveticus<\/em>, <em>Lactobacillus casei <\/em>subsp. <em> pseudoplantarum<\/em> and <em>Lactobacillus brevis<\/em>, but also contains <strong>yeasts<\/strong> (10-17% of the total) such as <em>Kluyveromyces marxianus <\/em>var. <em> lactis<\/em>, <em>Saccharomyces cerevisiae<\/em>, <em>Candida inconspicua<\/em> and <em>Candida maris<\/em>.  <strong>[5]<\/strong><\/p>&#13;\n&#13;\n<p>Lo <em>\n  <strong>yakult<\/strong>\n<\/em>, on the other hand, is a Japanese probiotic beverage made from <strong>skim milk fermented<\/strong> by <em>Lactobacillus paracasei Shirota<\/em>, with a flavor derived from the heat treatments that occur before fermentation and the additions of ingredients that occur after fermentation. And then there is <strong>yogurt,<\/strong> which we are all familiar with, which can only be sold under that name in Italy if it is <strong>produced by fermentation<\/strong> by <em>Streptococcus thermophilus<\/em> and <em>Lactobacillus delbrueckii <\/em>subsp.<em> bulgaricus<\/em>. In short, from great varieties of microbes come great varieties of fermented milk.<\/p>&#13;\n&#13;\n<p>Because microorganisms are present in many of the fermented milk products in very high amounts and manage to reach the intestines alive, for some of these we can speak of true <strong>probiotics<\/strong>.  <strong>[6]<\/strong> Online you can find many sites extolling its <strong>beneficial<\/strong>,<strong> protective<\/strong> and in some cases even <strong>therapeutic<\/strong> <strong>properties<\/strong>. For a more in-depth look at how to weigh the many pieces of information circulating about the <strong>health effects of probiotics<\/strong>, we refer you to <strong>\n  <a href=\"https:\/\/ingredients.saccosystem.com\/en\/probiotics-and-health-benefits-a-journey-through-the-scientific-literature\/\">this article<\/a>\n<\/strong>.<\/p>&#13;\n&#13;\n<p>\u00a0<\/p>&#13;\n<hr class=\"wp-block-separator\" \/>\r\n<div class=\"wp-block-spacer\" style=\"height: 30px;\" aria-hidden=\"true\">\u00a0<\/div>\r\n&#13;\n<h3 class=\"wp-block-heading\" id=\"fonti\">Sources and notes<\/h3>&#13;\n&#13;\n<p>[1] This behavior is called the &#8220;Crabtree effect&#8221; and is also typical of some cancer cells<\/p>&#13;\n&#13;\n<p>[2] For a historical survey of investigations into the composition of kefir and to learn more about the microorganisms that live in it, I point to this article Edward R. Farnworth, <em>Kefir &#8211; A complex probiotic<\/em> (2005), <em>Food Science &amp; Technology Bulletin Functional Foods<\/em> <strong>2<\/strong>(1), pp. 1-17, DOI: 10.1616\/1476-2137.13938]<\/p>&#13;\n&#13;\n<p>[3] To brush up on the differences between bacteria and yeasts, you can review <strong>the article &#8220;Variety Fair<\/strong> &#8221; <a href=\"https:\/\/ingredients.saccosystem.com\/en\/microorganisms-lets-learn-about-them-and-recognize-them\/\" target=\"_blank\" rel=\"noreferrer noopener\">\n  <u>https:\/\/ingredients.saccosystem.com\/conoscere-e-riconoscere-i-microrganismi\/<\/u>\n<\/a><\/p>&#13;\n&#13;\n<p>[4] SOURCE. <a href=\"https:\/\/www.livescience.com\/45614-what-is-buttermilk.html\" target=\"_blank\" rel=\"noreferrer noopener\">\n  <u>https:\/\/www.livescience.com\/45614-what-is-buttermilk.html<\/u>\n<\/a><\/p>&#13;\n&#13;\n<p>[5] SOURCE Simova E. <em>et al<\/em>, <em>Lactic acid bacteria and yeasts in kefir grains and kefir made from them<\/em>, 2002, <em>J Ind Microbiol Biotechnol.<\/em>, <strong>28<\/strong>(1), pp. 1-6. doi:10.1038\/sj\/jim\/7000186<\/p>&#13;\n&#13;\n<p>[6] See, in this regard, also the article https:\/\/ingredients.saccosystem.com\/probiotici-cosa-si-cela-dietro-questo-nome\/<\/p>&#13;\n","protected":false},"excerpt":{"rendered":"<p>&#13; For the past few weeks, an old acquaintance has reappeared in my house. I haven&#8217;t seen kefir in years, so much so that I associate it with my teenage days. I still remember when this fermented milk first entered our house, received as a most precious gift from a family friend, with a thousand [&hellip;]<\/p>\n","protected":false},"author":7,"featured_media":9308,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[276],"tags":[322,323,273,274,288,275],"class_list":["post-10043","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ingredients-en","tag-fermentation","tag-kefir-en","tag-lactic-ferments","tag-probiotics-en","tag-yeasts","tag-yogurt-en"],"acf":[],"_links":{"self":[{"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/posts\/10043","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/comments?post=10043"}],"version-history":[{"count":2,"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/posts\/10043\/revisions"}],"predecessor-version":[{"id":11549,"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/posts\/10043\/revisions\/11549"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/media\/9308"}],"wp:attachment":[{"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/media?parent=10043"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/categories?post=10043"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ingredients.saccosystem.com\/en\/wp-json\/wp\/v2\/tags?post=10043"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}