What is the significance of fermentation

Fermentation occurs under anaerobic conditions absence of oxygen , with the action of microorganisms yeasts, bacteria and molds that extract energy from the process. Some species of yeast, such as Saccharomyces cerevisiae , prefers fermentation to aerobic respiration, even when oxygen is abundant, as long as there is an adequate supply of sugar.

Fermentation is not limited to yeast but can also be carried out in muscles, in which the muscles catalyze the conversion of glucose to lactate. Glycolysis , which is the metabolic pathway that converts glucose to pyruvate, is the first step in fermentation.

During the process of glycolysis, one molecule of glucose, a six carbon sugar, breaks down into two pyruvate molecules. In the presence of oxygen, the pyruvate may then be oxidized through the tricarboxylic acid cycle, a process known as aerobic respiration. Conversely, the pyruvate may be reduced to alcohol, lactic acid or other products in the absence of oxygen, in the fermentation process. There are many types of fermentation, distinguished mainly by the end products. Ethanol fermentation is used in the production of alcoholic beverages.

Lactic acid fermentation is used to flavor or preserve dairy and vegetables. Lactic acid fermentation also occurs in muscle cells under strenuous activity. In this case, muscles consume energy ATP faster than oxygen can be supplied, resulting in an anaerobic environment and thus lactic acid buildup and sore muscles.

There are other types of fermentation such as acetic acid fermentation, acetone-butanol-ethanol fermentation and mixed acid fermentation.

Ethanol fermentation is defined as the biological process that turns sugar glucose, fructose and sucrose into ethanol, carbon dioxide and energy. After the initial glycolysis step that converts one glucose molecule to two pyruvate molecules, the pyruvate molecules further break down into two acetaldehyde and two carbon dioxide molecules, a step catalyzed by pyruvate decarboxylase.

Alcohol dehydrogenase then facilitates the conversion of the two acetaldehyde molecules to two ethanol molecules, utilizing the energy and hydrogen from NADH. Lactic acid fermentation is another type of fermentation and is described as the metabolic process that transforms sugar into the metabolite lactate and energy.

It is the only respiration process that does not produce a gas and occurs in some bacteria such as lactobacilli and muscle cells. This redox reaction is catalyzed by lactic acid dehydrogenase.

Lactic acid bacteria can carry out either homolactic fermentation, where lactic acid is the major product, or heterolactic fermentation, where some lactate is further metabolized into ethanol, carbon dioxide and other byproducts. Rich in probiotics , fermented foods contain microorganisms that can help maintain a healthy gut system, so it can extract nutrients from food more efficiently.

They are beneficial for human health in a number of ways. The probiotics, enzymes and lactic acid in fermented foods can facilitate the intake of vitamins and minerals by the body. Fermentation increases vitamins B and C and enhances folic acid, riboflavin, niacin, thiamin and biotin, making them more accessible for absorption. The cooked beans are generally used in flavorful foodstuff throughout the world, some other species of red beans and cow peas were consumed as vegetables in some parts of the country [7].

The large quantity of red beans are widely consumed, even though they are poorly digested and cause flatulence due to the presence of several biologically active compounds phytochemicals such as phytic acid, tannins, saponins and lectins which could limit their consumption [8].

The flatulence associated with red beans is mainly caused by oligosaccharides, particularly raffinose, stachyose and verbascose. Plant foods are fermented to enhance or create unique flavors, to change textural properties and to improve quality and digestibility. Fermented foods are an essential part of the human diet in many parts of the world, especially in Southeast Asia, the Near East and parts of Africa [9]. Microorganisms used for fermentation process of food products are capable of growing on a wide range of substrates.

That can produce a remarkable spectrum of products and bioactive components, which enhance the biofunctionality of food products [10]. The relatively recent advent of in vitrogenetic manipulation has extended the range of products that may be produced by microorganisms and has provided new methods for increasing the yields of existing ones [11]. The fermentation technology depends on the microbial components and produces different molecules from small laboratory scale to large industrial scale.

Fermentation of beans has not been extensively studied but it has been shown to produce a reduction in bioactive compounds phytochemicals , positive effects on protein digestibility, texture and aroma and an improvement in the biological value of legumes [13]. In spite of all these studies, there is still little formation concerning the use of open and controlled fermentation in P vulgaris in the developing country [14].

Especially on the eastern and great lakes part of Africa, where such beans are consumed in large quantities. The main aim of the work is to determine the reduction or elimination of flatulence-causing sugars and the enhancements of in vitro protein digestibility by natural and controlled fermentation.

The study focus on the change in chemical composition after fermentation of red beans. Anger, Canscope and Loko red kidney beans was purchased from framer of Ethiopia. The seeds were cleaned and the extraneous materials carefully removed by hand sorting. All analytical grade chemicals hydrochloric acid and sodium hydroxide and reagents Sorbic acid were used for experimental work.

The experiment has been carried by natural fermentations and controlled fermentation on flatus-producing compounds, phytates, tannins, protease inhibitors, saponins and invitro protein digestibility of bean flour were studied. The method for fermentation process was categorized into natural and controlled fermentation. The experimental steps fallowed for fermentation is shown in Fig. Each variety of test bean samples was cleaned and sorted out by size, colour and appearance, and absence of foreign or abnormal odors and living or dead insects.

The bean samples were finely ground in appropriate analytical mill and sieved through a 0. Sorbic acid 0. Titratable acidity was determined daily according to AOAC by titrating with 0. During the fermentation process, the pH was also measured daily on the sample homogenates using a pH meter. After fermentation, the slurries were collected daily and freeze-dried for subsequent analysis of bioactive compounds concentration, flatulence-producing factors and protein digestibility of fermented beans.

For succeeding experimental analysis, the fermented freeze-dried samples were milled to pass through 0. Thermophilic lactic culture was obtained from Chr.

These microorganisms are commonly used for fermented milk production. In order to obtain sterile flour, beans were rinsed four times in distilled water, drained and dried with a cloth to remove any adhering dust and foreign materials.

The suspensions were subsequently subjected to heat treatment process in an autoclave 1. Titratable acidity and pH of the bean suspension samples were collected daily and measured on daily basis from the initial to the last day of fermentation. The total phenolics were measured by spectrophotometer at nm using Folin Ciocelteau reagent in alkaline medium, and were expressed as cafeic acid equivalents. Tannins were determined using the Vanillin-HCL method.

One trypsin inhibitor unit was defined as an increase of 0. In vitro protein digestibility of raw and processed samples was measured according to the method of Minekus et al.

About mg sample was suspended in 15 ml of 0. The mixture was then neutralized with 0. The mixture was then centrifuged at rpm for 5 min. About 5. Proximate analyses: The proximate analyses of sample for moisture, crude fat, crude fibre and total ash were carried out in triplicate according to the methods of Association of Official Analytical Chemists [16].

Nitrogen was determined by the micro-Kjeldahl method and the percentage nitrogen converted to crude protein by multiplying by 6. The total carbohydrate content was determined by difference according to given in AOAC [16]. All the metals were determined by Atomic Absorption Spectrophotometer Solar Unicam with exception of sodium and potassium that were determined using a flame photometer Model , Coring UK. Analyses were performed in triplicate.

The effect of fermentation on pH change was observed during open fermentation and controlled fermentation, which represents in Fig. The result indicates that after 48 h of fermentation the pH decreased significantly, but pH values reduced more in OF than in CF. These results were observed for all three processed varieties of fermented red beans flour.

The decrease in pH is might be due to the production of lactic bacteria during open fermentation. The differences may be due to the use of different legume species and varieties.

With the origin of the grain being very different, it is probable that the amount and nature of endogenous micro flora are also different. It was also observed that bean flour fermented naturally had a lower pH than those prepared by controlled fermentation. Therefore there was more and efficient acidic fermentation in open fermentation. Like in many traditional fermentation products the drop in pH results is a means for protection from many food pathogens.

The removal of bioactive compounds and flatulence-causing factors through fermentation would serve as a major benefit to bean consumers [21]. The microbial effect on flatulent producing compound Stachyose and Raffinose contents of red bean flours in open and controlled is presented in Fig.

It was found that stachyose and raffinose are changed throughout the fermentation experiment. After 72 h of open fermentation the concentration of raffinose for all bean varieties was decreased to an un-expectable level.

Some lactic acid bacteria contain galactosidase and may utilize oligosaccharides [22]. Thus, elimination of oligosaccharides might be due to the ability of some of the lactic acid organisms to utilize raffinose and stachyose for their metabolism. These results indicated that the society of micro organisms present in open fermentation is able to produce enzymes that are capable of breaking down these oligosaccharides into an absorbable form.

This was not the case for the organisms used in the controlled fermentation [23]. It was found that the control value zero time of phytic acid, trypsin inhibitors and saponins were different for open and controlled fermentation.

This might be due to the samples for controlled fermentation was sterilized before inoculation, which attributes leading to decrease the heat labile antinutritional factors.

Controlled and open fermentation had eliminated most of the phytic acid in red bean flours after 72 h of fermentation. This attribute to the inactivation of plant-based phytases during the sterilization process, an increase in phytase loss occurred during controlled fermentation. Furthermore, this can also be attributed to higher microbial phytases produced by the pure cultures [24]. For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.

It was observed that trypsin inhibitor activity reduced significantly in open fermentation for all three bean varieties. Fermentation of lentils for 96 h brought about a decrease in trypsin inhibitor activity and a sharp drop in the ratio of tannin which is a desirable feature from a nutritional point of view. The digestibility of protein in the fermented samples was augmented compared to the non-fermented beans as a result of TIA diminution as noted later.

The trypsin inhibitors were also shows the reduction with the fermentation time during the controlled fermentation [25]. It was measured in milligram of per gram of beans flour. It may be due to break down the polyphenols in the beans by organism.

During the preparation of many fermented foods, tannins are reduced before the fermentation step because of their localization in the outer layers or seed coats of the raw ingredients. In several fermented foods the seed coat or testa is removed from the substrate before fermentation so the antinutritional potential caused by the presence of tannins is of little concern [26].

The effect of fermentation in vitro protein was study during open and controlled fermentation is representing in Fig. It was observed that the anger red bean shows It might be due to protein denaturation and inactivation of trypsin inhibitor by heat treatment. Micro flora produces some proteolytic enzymes during fermentation which are responsible for increased protein digestibility of fermented red beans [27].

In this study, phytic acid which is known to inhibit the proteolytic enzymes was eliminated in red bean flour samples fermented at room temperature. It is an anaerobic reaction, which means it requires no oxygen to be present other than the oxygen atoms contained in the sugar. The other ingredient required for the reaction to take place is yeast.

Fermentation is a metabolic process used by bacteria under anaerobic conditions to generate energy for cell growth. The most common reaction to fermented foods is a temporary increase in gas and bloating. This is the result of excess gas being produced after probiotics kill harmful gut bacteria and fungi.

Drinking too much kombucha can also lead to excess sugar and calorie intake, which may also lead to bloating and gas. From an industrial perspective, fermentation is a slow and inefficient process. This means it carries a higher cost of production and requires more energy and resources. During the fermentation process, the sugar is turned into biomass yeast cells , energy heat and carbon dioxide.

As molasses are a renewable raw material, the fermentation process does not result in net emissions of carbon dioxide into the atmosphere. Probiotics secrete antimicrobial peptides that kill harmful pathogenic organisms like Salmonella and E. Zanini, a spokeswoman for the American Academy of Nutrition and Dietetics, often recommends two to three servings of fermented foods per day.

In nature, yeast enzymes break down the complex carbon compounds of plant cell walls and animal tissues, feeding on the sugar produced in the process. In this way, yeast function as natural decomposers in the environment. Yeast Fermentation and the Making of Beer and Wine. Humans have taken advantage of the metabolism in a tiny fungus called yeast to create beer and wine from grains and fruits.

Upon a strictly biochemical point of view, fermentation is a process of central metabolism in which an organism converts a carbohydrate, such as starch or sugar, into an alcohol or an acid.

For example, yeast performs fermentation to obtain energy by converting sugar into alcohol. Many organisms will also ferment pyruvic acid into, other chemicals, such as lactic acid.

Humans ferment lactic acid in muscles where oxygen becomes depleted, resulting in localized anaerobic conditions. This lactic acid causes the muscle stiffness couch-potatoes feel after beginning exercise programs. When oxygen is not present or if an organism is not able to undergo aerobic respiration, pyruvate will undergo a process called fermentation.