Microbiological and Metabolomic Insights into Oat Okara Fermentation

Lian Bin^*
*Correspondence: Lian Bin, Department of Food Science, University of Copenhagen, Frederiksberg C, Denmark, Email:

Introduction

Oat okara, a byproduct of oat milk production, is gaining attention as a valuable source of nutrients, fibers, and bioactive compounds. Oat milk, made by blending oats with water and then straining the mixture, produces oat okara as the solid residue left behind. Traditionally, this byproduct has been considered waste, but recent developments in food science and fermentation technology are highlighting its potential as a functional ingredient. The fermentation of oat okara has garnered interest due to its ability to enhance the nutritional profile, improve digestibility, and introduce bioactive metabolites that offer health benefits. Understanding the microbiological and metabolomic changes that occur during oat okara fermentation is crucial for optimizing its fermentation processes and harnessing its full potential as a functional food. Fermentation, the process by which microorganisms such as bacteria, yeasts, and fungi break down organic substances to produce useful metabolites, plays a significant role in the transformation of raw materials into value-added products. In the case of oat okara, fermentation can improve its functional properties by increasing the bioavailability of nutrients, degrading antinutritional factors, and generating beneficial compounds such as probiotics, vitamins, and organic acids. The microbiological aspects of oat okara fermentation are of primary importance in determining the types of microorganisms that can effectively ferment this substrate and the resulting changes in the nutritional composition of the okara.

Description

Oat okara contains a complex mixture of fibers, proteins, fats, and carbohydrates. Its high fiber content, particularly beta-glucans, makes it a promising candidate for fermentation. Beta-glucans, a type of soluble dietary fiber, have been linked to numerous health benefits, including lowering cholesterol levels, improving heart health, and regulating blood sugar levels. During fermentation, microbial enzymes can break down these fibers into smaller oligosaccharides and Short-Chain Fatty Acids (SCFAs), which can have additional health-promoting effects, such as supporting gut health and enhancing immune function. Certain strains of Lactic Acid Bacteria (LAB), which are commonly used in food fermentation, are capable of degrading these complex polysaccharides and transforming them into more digestible forms, thereby improving the overall nutritional value of oat okara. The microbiological diversity of oat okara fermentation is a key factor in determining the final product's properties. Several groups of microorganisms are involved in oat okara fermentation, with LAB, yeasts, and molds being the most prominent. Lactic acid bacteria are the primary microorganisms responsible for fermentation in many plant-based foods. LAB strains, such as Lactobacillus, Bifidobacterium, and Streptococcus species, have been widely studied for their ability to ferment various substrates and produce beneficial metabolites, including organic acids, antimicrobial compounds, and exopolysaccharides. The presence of these microorganisms during oat okara fermentation can result in the production of lactic acid, which lowers the pH of the substrate and contributes to the preservation and safety of the fermented product. Additionally, LAB can outcompete harmful microorganisms, enhancing the shelf life and safety of the fermented oat okara [1].

The selection of appropriate microbial strains is critical to the success of oat okara fermentation. Researchers have investigated different strains of LAB and other microorganisms to determine which are most effective at fermenting oat okara and improving its functional properties. The fermentation process can be further optimized by adjusting factors such as temperature, pH, oxygen levels, and fermentation time. These parameters influence the activity of the microorganisms, as well as the types of metabolites produced. For example, some strains of Lactobacillus may produce higher levels of lactic acid and other bioactive compounds under anaerobic conditions, while others may be more effective at producing antioxidants or other health-promoting substances in different environments. One of the key aspects of metabolomics is the study of the metabolites produced during fermentation. Metabolomics provides valuable insights into the biochemical changes occurring during fermentation, allowing researchers to identify the specific metabolites generated and their potential health benefits. In the case of oat okara fermentation, metabolomic profiling can reveal the production of various organic acids, including lactic acid, acetic acid, and butyric acid, as well as other bioactive compounds such as peptides, phenolic compounds, and polyunsaturated fatty acids. These metabolites can have diverse effects on human health. For example, organic acids such as lactic acid help to lower the pH of the substrate, creating an environment that is inhospitable to pathogenic bacteria while promoting the growth of beneficial microorganisms. Short-chain fatty acids, which are produced during the fermentation of fibers, are known to have anti-inflammatory and gut-health-promoting properties. These compounds are also linked to improved nutrient absorption, immune modulation, and gut microbiota balance [2].

In addition to organic acids, the fermentation of oat okara can also lead to the production of bioactive peptides. These peptides, which are derived from proteins during fermentation, have been shown to exhibit a range of biological activities, including antioxidant, antihypertensive, and antimicrobial effects. Peptides can be generated through the action of microbial enzymes that break down the protein content of the okara. This process can enhance the functional properties of oat okara, making it a more valuable ingredient in the development of health-promoting foods. Furthermore, the enzymatic hydrolysis of proteins during fermentation can improve the digestibility of the okara, making it easier for the body to absorb the nutrients. Phenolic compounds are another important group of metabolites produced during the fermentation of oat okara. These compounds, which include flavonoids, phenolic acids, and lignans, have been shown to possess antioxidant properties that can help protect cells from oxidative damage. The fermentation process can enhance the bioavailability of these phenolic compounds by breaking down their complex forms into more absorbable metabolites. The antioxidant activity of phenolic compounds is particularly important for reducing the risk of chronic diseases such as cardiovascular disease, diabetes, and cancer. Therefore, the production of phenolic compounds during oat okara fermentation can significantly improve the health benefits of the final product [3].

Polyunsaturated Fatty Acids (PUFAs) are another group of beneficial metabolites that can be influenced by fermentation. Oat okara contains a small amount of PUFAs, primarily linoleic acid, which can be further metabolized during fermentation. Some strains of microorganisms, particularly certain yeasts and molds, can produce additional PUFAs, which have been associated with numerous health benefits, including anti-inflammatory effects, improved heart health, and enhanced brain function. By optimizing the fermentation conditions, it is possible to increase the concentration of these valuable fatty acids in the final product. The metabolomic changes that occur during oat okara fermentation are not limited to the production of organic acids, peptides, phenolic compounds, and PUFAs. Other metabolites, such as amino acids, vitamins, and exopolysaccharides, can also be generated during the fermentation process. Amino acids, the building blocks of proteins, are essential for various physiological functions, including tissue repair, immune response, and neurotransmitter synthesis. Fermentation can increase the levels of certain amino acids, such as glutamine, leucine, and lysine, which are crucial for human health. Vitamins, particularly B vitamins, are also produced during fermentation and play vital roles in metabolism, immune function, and energy production [4].

Exopolysaccharides, which are high-molecular-weight carbohydrates produced by some strains of microorganisms during fermentation, can also contribute to the functional properties of fermented oat okara. These polysaccharides can have prebiotic effects, promoting the growth of beneficial gut bacteria and improving gut health. Additionally, exopolysaccharides can improve the texture and mouthfeel of fermented products, making them more appealing to consumers. The optimization of oat okara fermentation for the production of functional foods requires careful consideration of the microbial and metabolomic factors that influence the final product. Research is ongoing to identify the best microbial strains and fermentation conditions to maximize the production of bioactive metabolites while maintaining the sensory and nutritional qualities of the oat okara. Advances in fermentation technology, such as the use of mixed cultures of microorganisms, co-fermentation, and controlled fermentation environments, hold promise for enhancing the efficiency and scalability of the fermentation process. By understanding the microbiological and metabolomic aspects of oat okara fermentation, it is possible to develop innovative, functional fermented products that offer a wide range of health benefits, paving the way for more sustainable and nutritious plant-based foods [5].

Conclusion

In conclusion, the fermentation of oat okara offers exciting possibilities for the development of functional foods that provide health benefits beyond basic nutrition. By exploring the microbiological and metabolomic changes that occur during fermentation, researchers can better understand the processes that enhance the nutritional and bioactive properties of oat okara. As the demand for plant-based and functional foods continues to grow, the fermentation of oat okara could play a key role in meeting consumer needs for innovative, health-promoting products. Through further research and optimization of fermentation processes, oat okara could become a valuable ingredient in the production of functional fermented foods with a broad range of health benefit.

Acknowledgment

None.

Conflict of Interest

None.

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