Question

The enzyme used in isomerization of corn starch during the making of High Fructose Corn Syrup is/are:
(A). Alpha-amylase
(B). Glucoamylase
(C). Glucose isomerase
Choose the most appropriate answer from the options given below:

• A. (A) and (B) only
• B. (B) and (C) only
• C. (B) only
• D. (A), (B) and (C)

Hint:

Remember the HFCS enzyme chain: 1. \textbf{Alpha-amylase} cuts the big starch chains (liquefaction). 2. \textbf{Glucoamylase} cuts the small chains into glucose (saccharification). 3. \textbf{Glucose Isomerase} converts glucose to fructose (isomerization).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The production of High Fructose Corn Syrup (HFCS) from corn starch is a multi-step enzymatic process. It involves breaking down the large starch polymer into glucose and then converting a portion of that glucose into fructose.
Step 3: Detailed Explanation:
The process uses a sequence of three key enzymes:
1. (A) Alpha-amylase: This enzyme is used in the first step, liquefaction. It breaks down the long-chain starch molecules into smaller polysaccharide chains called dextrins.
2. (B) Glucoamylase: This enzyme is used in the second step, saccharification. It breaks down the dextrins into individual glucose molecules, resulting in a glucose syrup.
3. (C) Glucose isomerase: This is the crucial third enzyme. It is used in the isomerization step, where it converts a portion of the glucose molecules into fructose molecules. Since fructose is much sweeter than glucose, this step creates the "high fructose" syrup.
The question asks which enzymes are used "during the making" of HFCS, which implies the entire process from starch. Therefore, all three enzymes are involved.
Correction Note: The original question text is slightly ambiguous. It asks about "isomerization of corn starch". Isomerization is only one step, performed by glucose isomerase (C). However, it also says "during the making of High Fructose Corn Syrup", which covers the whole process. Given the options, the question is interpreted to mean the entire manufacturing process. If the question meant ONLY the isomerization step, the answer would be (C) only. But since (A), (B), and (C) is an option, it is intended to cover the entire process.
Step 4: Final Answer:
The entire process of making HFCS from corn starch involves alpha-amylase, glucoamylase, and glucose isomerase. Therefore, option (D) is the most comprehensive answer.