What is Enzyme Effect?
The term “enzyme effect” denotes the capacity of enzymes to catalyze reactions in living organisms without being consumed. Enzymes are biocatalysts (mostly proteinaceous) that lower the activation energy for the reaction to occur. Thus, enzymes allow critical biochemical processes, such as digestion, respiration, or even replication of DNA, to occur at the required pace and efficiency. Enzymes are precise and specific to certain substrates. Enzymes and substrates bind to form an enzyme-substrate complex, and the complex catalyzes the reaction to yield the product.
Several factors influence the enzyme effect. These include temperature, pH, concentration of substrates, and the presence of inhibiting or activating factors. Each enzyme is functionally optimal at a given temperature and pH. When the temperature is elevated, or pH altered, the enzyme undergoes denaturation and loses its functional shape, thus, the enzyme effect is diminished or stopped. The concentration of substrates also impacts rate of reaction. Enzyme activity is optimal until all active sites on enzymes are saturated. Enzymes facilitate and accelerate the vital, metabolic reactions that sustain and support life.
Enzyme Effect on Dough Stability
Dough stability describes how dough maintains its strength and resistance throughout the mixing, fermentation and processing stages. Stability of dough is enhanced using enzymes due to their ability to alter both the chemical and physical structures of the components of flour (starch, proteins and non-starch polysaccharides). Enzymes are natural biocatalysts and play a major role in improving the performance and handling of dough and provide a better-quality end product. The baking industry has routinely adopted the controlled use of enzymes since it is a greener technology and cleaner alternative over chemical dough improvers.
Dough Stability and Enzymes
Each type of enzyme is unique and affects the stability of dough differently. For example, Amylases, which breakdown starch, provide fermentable sugars which substantially improves the yeast activity during fermentation and in turn, gas production. Xylanases improve dough extensibility while Xylanases, which breakdown arabinoxylans (hemicellulose), also improve the water absorption of the dough. While decreasing the strength of gluten, the dough becomes more easily processed thanks to the activity of Proteases. Excessive amounts of Protease can affect dough stability negatively. Glucose oxidase, on the other hand, can strengthen gluten through oxidation and can crosslink disulfide bonds of gluten.
Enzyme Performance
Dough performance is affected by mixing conditions, like mixing time, temperature, and even flour quality. In addition, fermentation, pH, and enzyme concentration also affect dough performance. Enzyme concentration is probably the most critical factor that needs balancing. Insufficient concentration can lead to a poor effect, but excessive amounts weaken dough and alter the desired dough texture. When evaluating the performance of enzymes, flour quality and protean concentration is also very important. When all these factors are kept in balance, the enzymes perform effectively.
When enzymes are added, dough stability is enhanced. Gas retention is also improved, and the crumb structure of the dough is more consistent. This also leads to an improvement in loaf volume and softness. The staling process of bread is also slowed down, enhancing shelf life. Enzymes have also improved modern baking technology because they are considered very effective tools and are used in very small and specific amounts. Enzymes are not only very important; they are also irreplaceable in bread and baking production.
Enzyme Effect on Rheology
Rheology is defined as the science of the flow and deformation of matter and is important in the study of baking science and food processing. Dough rheology in conjunction with mixing, fermentation, sheeting and baking illustrates the behavior of dough. Desirable rheological properties of dough offer handleability, gas retention and quality of baked products in terms of volume, texture and crumb structure. Enzymes offer an important opportunity in the field of dough rheology, as they target starch, proteins and cell wall polysaccharides. Because of the high specificity of enzymes, they are excellent and safe additions to modern baking since they improve dough functionality and neither leave harmful residues.
Effect of Enzyme on Dough Rheology
There are different ways in which different classes of enzyme effect on rheological properties of dough. Amylases work to hydrolyze starch to form fermentable sugars, which in turn enhances dough fermentation and improves the elasticity and loaf volume of formed dough after fermentation. Xylanases catalyze the breakdown of arabinoxylans resulting in the enhancement of the water equilibrium within dough and the extensibility and easy handling of dough. Hydrolysis of gluten is also catalyzed by proteases, which also results in soft and easy to shape dough. Excess proteolytic activity on the other hand can be detrimental to the dough gluten network and gas retention. Lastly, glucose oxidase can improve dough elasticity, stability and resistance to stress of mixing by strengthening the gluten network.
Influencing Factors of Enzymes and their Properties
Rheological properties of dough are influenced by several factors, including types and concentrations of enzymes, the composition of flour, mixing parameters, temperature, pH, and fermentation time. Enzymes need to be added in the correct amounts, since too little or too much of them is not beneficial and can even negatively affect the quality of dough. Enzyme performance also impacts the quality of dough, particularly the proteins and the composition of the flour. If optimal conditions are not maintained, then enzymes may not perform correctly. These conditions would be quality of the dough and performance of the enzymes. Bakers adjust the optimal conditions to balance dough strength and extensibility and elasticity.
The positive enzyme effect used in the correct amounts is the controlled improvement of elasticity and extensibility of dough, in addition to improved water absorption, gas retention and mixing tolerance. Once the optimal performance of the dough is achieved, the dough is able to withstand mechanical handling. This improves fermentation and baking. The result of the process is an improved volume of bread, an improved crumb structure, an improved softness and an improved consistency of the end bread product. Enzymes form the basis of clean label baking since they reduce the need for chemical dough conditioners and enable sustainable bakery practices and high quality baked dough.
Dough Stability of Different Enzymes
Amylases
Amylases break down starches into smaller carbohydrates. Among many fermentable carbohydrates present in bread dough, α-amylase breaks down starch into sugars for yeast fermentation, which in turn releases carbon dioxide. Increased carbon dioxide gases causes the dough volume and loaf volume to increase. Having optimal amounts of amylases in bread dough promotes dough stability and gas production. Amylase can modify and delay the staleness of bread. However, Amylase can weaken dough stability, which can form a sticky, unmanageable dough.
The volume of bread can also be affected negatively if amylase is present in excessive amounts. In order to achieve optimal dough balance without compromising stability and quality, bakers need to control the amount of amylases used. The final product can also be adversely affected in terms of softness and ease of handling without optimal amounts of amylases present in bread dough.
Xylanases
Xylanases cleave arabinoxylans, wheat flour’s prevalent non-starch polysaccharide in the cell wall. Water-unextractable arabinoxylans trap water and inhibit gluten network formation, rendering the dough hard and not extensible. Xylanase makes these insoluble arabinoxylans soluble, releasing water and improving the hydration of the dough.
This action facilitates the development of gluten, the extensibility of dough, and the retention of gas while the dough is in the proofing stage. Also, dough is more stable during mixing and able to withstand more mechanical stress. Improved dough stability increases loaf volume, crumb structure, and crumb softness. However, polysaccharides of the cell wall can be overly degraded, and the dough may lose gas and become sticky and too soft. The xylanase activity must be balanced to achieve the optimized level of extensibility of dough and retaining gas, resulting in improved stability.
Proteases
Proteases are applicable in certain bakery products because they hydrolyze the peptide bonds in certain gluten proteins, which weakens the gluten network. Dough extensibility is advantageous in products like biscuits, crackers, pizza and some flat breads, which are inherently relaxed. The use of proteases in these products helps shorten the time required for mixing, improves the dough’s workability and decreases the resistance during the sheeting and shaping operations.
On the other hand, gluten networks in products like bread are required for trapping the fermentation gasses, which stabilize the dough. The excessive use of proteases and the over-hydrolysis of the gluten proteins leads to a poor retention of the fermentation gasses, low loaf volume and a sticky, collapsed bread. Due to this, the use of proteases is largely limited to soft and low elastic dough products. The use of proteases in bread products is in very limited quantities.
Glucose Oxidase
Glucose oxidase is a class of oxidative enzymes that is a popular ingredient in bread production for dough strengthening. Glucose oxidase catalyzes the oxidation of glucose to form gluconic acid and releases hydrogen peroxide in the process. The hydrogen peroxide triggers the oxidation of the sulfydryl groups in the gluten proteins and facilitates the formation of additional disulfide bonds in the gluten network. Stronger cross-links strengthen the dough’s elasticity and strengthen the dough’s resistance to the physical forces of the mixing and the retention of gas.
Glucose oxidase strengthens dough stability due to the reinforced structure of gluten. Stabilized gluten makes dough resistant to stresses of fermentation and processing. Glucose oxidase also has the effect of increasing the volume of the bread, making the crumb texture of the bread finer, and also improving the bread’s resistance to the variability of mixing and proofing.
Carboxylester Hydrolases
Exogenous and endogenous carboxylester hydrolases interact with dough to hydrolyze lipids and form surface-active compounds that stabilize gas cells, thus improving dough handling and strengthening the dough matrix. The hydrolyzed lipids stabilize the gas cells, resulting in greater gas retention, increased loaf volume and a finer crumb structure.
Additionally, the use of endogenous carboxylester hydrolases improves the dough and the final baked product’s tolerance to mechanical mixing and increases baked product freshness by improving the interaction between starch and lipids. Carboxylester hydrolases also influence the interactions between lipids and proteins. This can impact dough strength and the resultant quality of the baked product. Carboxylester hydrolases should therefore be used in a controlled manner to greatly impact the quality of baked products.
Other Enzyme Effect on Dough Stability
Peroxidases
Peroxidases belong to the class of oxidative enzymes, which contribute positively to dough stability. They promote dough stability by providing strengthening effects on the gluten network via oxidation. Peroxidases catalyze the reduction of hydrogen peroxide and in the process, phenolic compounds and protein sulfhydryls in wheat flour are oxidized. This assists in the formation of additional covalent cross-links including disulfide bonds and dityrosine bonds, among gluten proteins and between gluten and other flour proteins, for example, arabinoxylans. This results in dough with improved mechanical characteristics and resistance to deformation during mixing and fermentation. Peroxidases also positively affect gluten bonds by improving gas retention.
This results in increased loaf volume and an improved crumb structure. Stiff dough also has improved resistance to overmixing and long fermentation. This results in improved processing in commercial bakeries. The disadvantage of excessive peroxidase activity is that dough can become too stiff and the gluten network can become too rigid. This will negatively affect the dough’s extensibility and lead to loaf volume collapse and a crumb structure that is too dense. This also impacts proofing. Peroxidases are therefore used in moderation
Laccases
Laccases improve dough stability by being involved in the oxidation of phenolic compounds via their multicopper oxidase activity. In wheat flour, one such phenolic compound is ferulic acid. Ferulic acid is often found connected to an arabinoxylan chain. Laccases oxidize ferulic acid and this part of the arabinoxylan undergoes coupling and forms covalent cross-links with other arabinoxylans and gluten proteins (or laccases) as well. This cross-linking results in the formation of a dough matrix with improved water retention and with improved resistance to deformation.
Dough that has been treated with laccase has better elasticity, gas retaining ability, and tolerance to mechanical processing, which leads to an increased loaf volume and better crumb structure. Laccases work well in other doughs as well, especially in whole wheat and high fiber doughs due to the higher content of arabinoxylans that improves cross-linking.
Laccases can also be used to neutralize the adverse effects of bran on the development of gluten. Another factor to consider is if laccases are overused, it can cause an opposite effect and produce a very rigid dough. This highly impacts gas retention during fermentation and greatly decreases loaf volume. The right amounts of laccases used can allow for the right balance between dough elasticity and laccases.
Food Enzyme Effect on the Human Body
Enzymes are catalysts that speed up chemical reactions in living cells. Enzymes have important functions in food processing and in human physiology. Different food processing industries employ different enzymes. For example, the baking industry employs amylases, xylanases, proteases, lipases, and glucose oxidase among others. Enzymes help improve the quality of the dough, improve the quality and shelf life of bread, and help with the handling of the dough.
While many of these enzymes are highly active when dough is being processed, many of them are inactivated during baking because of the extremely high temperatures that are achieved in the oven. This means that very little, if any, of the active enzyme is ingested by consumers of baked products. Food enzymes are considered processing aids because while food enzymes do help in the processing of food, they do not have any biological effects after the food is consumed.
Digestion and Metabolism of Food Enzymes
Food enzymes, like other dietary proteins, are digested by the gastrointestinal tract. Edible enzymes are processed by the digestive system like any other protein. Since enzymes do not remain in their intact state after food processing and consumption, they are not directly metabolically active in the human body. Rather, enzymes have a very important indirect contribution during food processing. Food enzymes improve quality, texture, shelf life, and digestibility of food.
Nutritional and Health Benefits
Although baking enzymes become inactive in the body post-digestion, the use of enzymes during food processing may result in many health benefits. Improving the way amylases modify starch means that carbohydrates become more accessible to yeast, resulting in better quality bread. Xylanases, and other enzymatic cell-wall modifiers, improve the quality of dough and may also enhance the availability of some dietary fiber.
Lipases and carboxylester hydrolases improve the softness and freshness of the crumb, hence lessening the potential for waste. Enzyme-modified baked goods often improve the digestibility, quality, and general acceptability of the product. Furthermore, the use of enzymes may substitute some chemical additives, hence allowing manufacturers to prepare cleaner-label products with more natural substances.
Safety and Potential Risks
Food enzymes that are approved for commercial use are subjected to thorough safety assessments by governing regulatory bodies prior to their use in food processing. Scientific studies have shown that the use of such enzymes in baking is safe. Because of the elevated baking temperatures, these enzymes become denatured, thereby making their active exposure through the final product, bread, negligible.
However, the potential of developing allergy and respiratory sensitization may be present during the exposure to concentrated enzyme powders among bakers. Such risks are limited to those handling the enzyme preparations and not the consumers of the baked products. Proper industrial hygiene, such as systems for the enclosed handling of the substances and the use of personal protective equipment, can reduce these occupational risks.
Ultimately, baking enzymes have minimal direct impacts on the human body because they are either made inactive during baking, or after consuming them, they will be digested as dietary proteins. The main contribution to the health of humans from baking enzymes is the improvement of the quality of food, digestibility, texture, freshness, and manufacturing efficiency. When food enzymes are used according to the regulatory guidelines, Food Enzymes are safe for consumers and are helpful in producing baked products that are high in quality, nutritious, and consistent.