The key difference between liquefaction and saccharification is that liquefaction is the conversion of starch into its soluble form, while saccharification is the conversion of soluble starch into glucose.
Sugar is an important sweetener that has become a vital commodity for food, beverage, and pharmaceuticals at both domestic and industrial levels. Starch is the primary source of sugar production. Starch is the carbohydrate reserve of plants like corn, potato, rice, cassava, wheat, and sorghum. In order to obtain sugar, the starch has to be hydrolyzed. The enzymatic hydrolyzation of starch into glucose syrup is considered to be more effective than acid hydrolysis. This is because enzymatic starch hydrolysis can produce greater starch conversion with a more specific and simple process. Normally, enzymatic conversion of starch needs two enzymes, namely α-amylase and amyl-glucosidase. Moreover, the process of enzymatic starch hydrolysis is divided into two steps as liquefaction and saccharification.
CONTENTS
1. Overview and Key Difference
2. What is Liquefaction
3. What is Saccharification
4. Similarities – Liquefaction and Saccharification
5. Liquefaction vs Saccharification in Tabular Form
6. Summary – Liquefaction vs Saccharification
What is Liquefaction?
Liquefaction is the process of converting starch into its soluble form. In this process, the starch is gelatinized and treated by α-amylase. Therefore, the starch is fragmented into regular-sized chains. Ultimately, the liquefaction process results in dextrin, maltose, malt-triose, and maltpentose. This liquefaction process is immediately followed by saccharification, which is the second stage of enzymatic hydrolysis of starch.
The method for producing a liquid starch solution that is suitable for saccharification (starch into glucose syrup) is technically called liquefaction. It is done by suspending starch in water and adding a heat-resistant α-amylase and a buffer to this mixture. Later, the pH of this mixture is adjusted in the range of 7.5 to 8. Finally, the starch milk is thermally treated while repressing possible hydrolysis of starch molecules. Furthermore, different enzymes can possibly optimize starch liquefaction in terms of quality, cost, and efficiency. However, α-amylase is the most widely used enzyme in the liquefaction process.
What is Saccharification?
Saccharification is the conversion of soluble starch into glucose. Saccharification is the second step in the starch hydrolysis process. In this step, dextrin, maltose, malt-triose, and malt-pentose are hydrolyzed to glucose syrup by amyl-glucosidase. After liquefaction, the temperature of the resulting mixture is lowered from about 50 °C to about 70 °C and the pH to about 6.5. Then the enzyme amyl-glucosidase is added to the mixture. Amyl-glucosidase is able to convert more than 90% of malt syrup to glucose, substantially free of microbial activity. This completes saccharification.
Furthermore, the glucose syrup of hydrolysate is then converted to lactic acid or ethanol by the fermentation process. The saccharification process should run smoothly in order to obtain a high yield of glucose syrup and a lower reversion rate. The challenges of the saccharification process may include uneven saccharification time, inefficient enzyme dose, and reversion to isomaltose again.
What are the Similarities Between Liquefaction and Saccharification?
- Liquefaction and saccharification are the two main steps of starch hydrolysis.
- Both processes are carried out by specific enzymes.
- Both processes are carried out under regulated temperatures and pH.
- These processes have different challenges.
What is the Difference Between Liquefaction and Saccharification?
Liquefaction is the conversion of starch into its soluble form, while saccharification is the conversion of soluble starch into glucose. Thus, this is the key difference between liquefaction and saccharification. Furthermore, liquefaction is catalyzed by the enzyme α-amylase, while saccharification is catalyzed by the enzyme amyl-glucosidase.
The below infographic presents the differences between liquefaction and saccharification in tabular form for side-by-side comparison.
Summary – Liquefaction vs Saccharification
Starch hydrolysis is the process of breaking down large starch molecules into smaller sugar molecules by adding water. Liquefaction and saccharification are the two main steps of starch hydrolysis. Both these processes are very important for domestic purposes and industrially. Liquefaction is the conversion of starch into its soluble form, while saccharification is the conversion of soluble starch into glucose. So, this is the key difference between liquefaction and saccharification.
Reference:
1. “Liquefaction.” An Overview | ScienceDirect Topics.
2. “Application of Saccharification Enzymes.” Infinita Biotech, 6 Sept. 2022.
Image Courtesy:
1. “Amylase reaction” By BQmUB2012134 – Own work (CC0) via Commons Wikimedia
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