What is the Difference Between Enzymatic and Non-enzymatic Browning

The main difference between enzymatic and non-enzymatic browning is that enzymatic browning involves enzymes, including catechol oxidase and polyphenol oxidase, whereas non-enzymatic browning does not involve any enzymatic action.

Enzymatic and non-enzymatic browning are two types of browning processes responsible for the color change of food. Browning can occur during the pre-preparation, processing, or storage of food.       

Key Areas Covered

1. What is Enzymatic Browning
     – Definition, Features, Function
2. What is Non-enzymatic Browning
     – Definition, Features, Function
3. Similarities – Enzymatic and Non-enzymatic Browning
     – Outline of Common Features
4. Difference Between Enzymatic and Non-enzymatic Browning
     – Comparison of Key Differences

Key Terms                                                                                                                  

Enzymatic Browning, Non-Enzymatic Browning

What is Enzymatic Browning

Enzymatic browning is the changing of color of the food into brown with the use of enzymes. Generally, polyphenol oxidase is the enzyme responsible for enzymatic browning. This enzyme or other enzymes catalyze the oxidation of phenols into quinones. However, these quinones undergo polymerization, forming melanins that can cause the brown color in fruits. Therefore, enzymatic browning in fruits and vegetables is not a favorable reaction. It may also cause undesirable heavy economic losses for growers. In addition, enzymatic browning is detrimental to fresh fruit and vegetables, including apples and potatoes, and seafood, such as shrimp.

Figure 1: Enzymatic Browning in Banana

Furthermore, enzymatic browning is beneficial for developing flavor in tea and developing color and flavor in dried fruit, including raisins and figs. However, enzymatic browning can be controlled by chemical reactions. It can also be controlled by destroying the responsible chemicals with heat. In vegetables, destroying enzymes helps to preserve the color in a process called blanching. In addition, lemon juice and other acids lowering the pH are important to preserve color in fruit.   

What is Non-Enzymatic Browning

Non-enzymatic browning is a set of chemical reactions taking place during the preparation or storage of food. The two types of non-enzymatic browning include caramelization and the Maillard reaction. Caramelization is a chemical reaction occurring in food when carbohydrates or sugars are heated. Generally, it removes water from food following isomerization and polymerization. On the other hand, the Maillard reaction is another type of chemical reaction occurring between amino acids and reducing sugars after the addition of heat.

Figure 2: Enzymatic Browning

Moreover, in the Maillard reaction, the nucleophilic amino group of the amino acid interacts with the reactive carbonyl group of sugars. This can also form poorly characterized flavor, and odor molecules can form during the Maillard reaction. In general, the type of amino acid determines the resulting flavor; therefore, Maillard’s reaction serves as the basis of the flavor industry. Moreover, this process accelerates in alkaline environments.   

Similarities Between Enzymatic and Non-enzymatic Browning

• Enzymatic and non-enzymatic browning are two types of processes that occur in food.
• Both can change the color of food, ranging from cream or pale yellow to dark brown or black.
• Furthermore, they can occur during the pre-preparation, processing, or storage of food.
• Their occurrence can vary in degree depending on the type of food and the extent of the reaction.
• In addition, browning can be either desirable or undesirable.
• Desirable browning makes food delicious, highly acceptable, and a quality product.
• Browning contributes to the aroma, flavor, and color of the product.
• Examples of browsing food include the browning crust of bread, all baked goods, potato chips, roasted nuts, roasted coffee beans, and many other processed foods.
• Undesirable browning may dehydrate food, including milk, eggs, dry fruits, cut fruits, citrus fruit juice concentrates, canned milk, and coconut. It can also produce off-odor and off-flavors.

Difference Between Enzymatic and Non-enzymatic Browning

Definition

Enzymatic browning refers to an oxidation reaction that takes place in some foods, mostly fruits and vegetables, causing the food to turn brown, while non-enzymatic browning refers to a set of chemical reactions that take place during the preparation or storage of foods responsible for the formation of brown compounds, which are volatile flavor molecules that affect the sensory quality of foods.

Occurrence

Enzymatic browning involves enzymatic reactions, while non-enzymatic browning involves chemical reactions.

Types

Moreover, enzymatic browning uses enzymes such as catechol oxidase and polyphenol oxidase, while caramelization and Maillard reaction are the types of non-enzymatic browning.

Conclusion                                                      

In brief, enzymatic and non-enzymatic browning are two types of processes that occur in food, changing color, odor, and flavor of food. Generally, enzymatic browning involves enzymatic reactions. The enzymes that are responsible for enzymatic browning include catechol oxidase and polyphenol oxidase. Meanwhile, non-enzymatic browning involves chemical reactions changing the color into brown in food. However, the main types of non-enzymatic browning include caramelization and the Maillard reaction. Therefore, the main difference between enzymatic and non-enzymatic browning is the type of browning.                                      

References:                

1. “Types of browning (enzymatic and non-enzymatic)”. Hmhub. 

Image Courtesy:

1. “Barangan banana Indonesia” By Midori – Own work (CC BY- SA 3.0) via Commons Wikimedia
2. “Enzymatic Browning of Avocados” By IBRay – Own Work (CC BY-SA 4.0) via Commons Wikimedia