Food

Kitchen Science: Bacteria And Fungi Are Your Foody Friends

As you sip a bowl of coffee, enjoy a rich chocolate treat or enjoy the perfume of a piece of Roquefort cheese, have you ever considered the extraordinary contribution made by the microscopic creatures that have worked so hard for your pleasure?

As the French pharmacist Louis Pasteur told: The persona of the infinitely small in nature is endlessly large-scale. Without microbes, life on this planet would not subsist or would be very different to what we see today.

Recent discoveries have uncovered the vital role played by microorganisms in driving ecosystems, changing environmental purposes and forcing the health and well-being of people, plants and animals.

One of “the worlds largest” fascinating aspects of microbiology is the virtually endless variety of biological and chemical process attributed to microbes. “Theres” species that can break down pollutants, happily grow on arsenic and the recently-described bacteria that break down PET plastics.

The wonders of fermenting

Nowhere is this biological activity more apparent and close to dwelling than through the process of fermenting. This metabolic process is used by many microbes largely bacteria and many yeasts and are used by humen in numerous industrial and agricultural applications.

Many of us are aware of respiration. The process is used by living cells to convert chemicals, such as sugar, to vigor by interrupting them down into smaller constituents and liberating the vigor within.

In the most familiar version, known as aerobic breathing, oxygen is the final recipient in a chain of chemical reaction that generates liquid and carbon dioxide and induces energy.

However, many bacteria are able to perform an alternative form of breathing given the absence of oxygen, called anaerobic breathing, which allows survival despite a lack of oxygen. This is a good trick that allows microbes to thrive in anaerobic situations, such as our bowel. Some bacteria live in forever anaerobic situations and, for them, exposure to oxygen is lethal!

But many microbes have another strategy: fermenting. Here, molecules such as sugars are only partly broken down; the vigor made is not as great as in breathing, but the cell still survives.

Luckily for us, many of the end-products of this process are very valuable, including compounds such as ethanol and lactic acid.

Cultured food

Although most people know that bacteria can grow milk into yoghurt and yeasts convert sugars in grape juice into ethanol or attain bread dough rise, there are countless examples in all regions of the world where fermenting is used to produce exotic and unique products of culture importance.

But many people dont realise the fullest extent to which fermenting enhances our relish of foods and beverages. In some examples, it may provide benefits beyond the senses.

In Colombia, Central America and Hawaii, Arabica coffee is processed by the wet technique, which involves a fermentation pace of 24 to 48 hours. This is primarily used to remove a thin stratum of mucilage surrounding the coffee bean.

This process also imparts desirable flavor and perfume properties. Of course, roasting and brewing are critical steps in the full development of coffee flavours.

Chocolate production begins when the chocolate bean undergoes a similar fermenting pace, which involves a complex succession of bacteria and yeasts growing flavour precursors, including ethanol, lactic acid and acetic acid.

The dairy industry relies heavily on fermentation. One instance is the simple starter cultures, consisting of one or a few bacteria that grow milk into yoghurt via lactic acid fermentation.

Theres likewise the complex mingle of bacteria and fungis that convert the curd into yummy products such as soft cheese, blue cheese and various matured cheeses.

And its is not simply kine milk; goat, sheep, buffalo and camel milk are likewise are exploited by cultures across the world to grow their own assortments of speciality fermented milk products.

Many of our favourite food or liquors look like this at some phase. Gal Chardon/ Flickr, CC BY-SA

Preservation

Apart from sensory advantages, fermenting is a form of food preservation that allows perishable foods to be stored for longer. This was an important aspect of food security before the introduction of refrigeration in the 19 th century.

Along with adding salt( antidote meat) or sugar( jams and cordials ), the acid produced during fermenting rapidly plunges the pH of the starting product. In the case of milk, this rise in sournes causes curdling but is also inhibitory to undesirable( and sometimes deadly) bacteria found in the raw milk.

Similarly, fermenting of meat products traditionally made from pork, but likewise beef, chicken and turkey involves a complex microbiological community of species. These generate lactic acid, acetic acid, diacetyl and make enzymes that break down protein and fats.

Some of the bacteria make hydrogen peroxide, which will react with myoglobin in the meat and lead to discolouration. To counter this, other bacteria are present that make the enzyme catalase, breaking down the hydrogen peroxide and preserving the pink colouring of the meat.

Some of the bacteria can also convert nitrates( added as preservatives) to nitrites, further enhancing the colour of the product.

Fermented foods expanded to vegetarian products, including the classic sauerkraut( fermented lettuce ), various fermented assortments of tofu( bean curd) and Spanish-style olives.

Farm swine likewise benefit from fermenting. In regions of the world where fresh grassland is not available time round, chopped plant substance( corn, sorghum and cereals) is allowed to naturally ferment to grow silage, which is used as fodder.

Its is not simply about flavor, perfume and nutrition though. Many of the microbes used in fermenting are considered as probiotics. While the jury is still out on the beneficial effects of probiotics, many studies have shown that their uptake connected to health benefits, including boosting the immune system.

So, next time you enjoy a glass of wine and a fine part of cheese on a crusty slice of sourdough bread, grow a toast to all the hard-working microscopic good guy!

Enzo Palombo, Professor of Microbiology, Swinburne University of Technology

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