Question

Ripening index in cheese is calculated as

• A. Total whey protein Total protein x 100
• B. soluble protein Total protein x 100
• C. Total casein Total protein x 100
• D. Total SNF Total protein x 100

Hint:

Cheese Ripening Formula: Ripening Index = $\frac{\text{Soluble Protein (WSN)}}{\text{Total Protein (TN)}} \times 100$. Indexes the depth of proteolysis during curing.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Quantitative proteolysis index during cheese curing: the Ripening Index (or Depth of Proteolysis Index) measures the percentage of total cheese nitrogen/protein that has been converted into water-soluble peptides and amino acids ($ ext{WSN} / ext{TN} imes 100$).
Key Formula or Approach:
\[ \mathbf{Ripening \text{ } Index (\%)} = \frac{\mathbf{Soluble \text{ } Protein \text{ (Water-Soluble Nitrogen WSN)}}}{\mathbf{Total \text{ } Protein \text{ (Total Nitrogen TN)}}} \times \mathbf{100} \]

Step 2: Detailed Explanation:
In cheese biochemistry, curing kinetics, and proteolysis assessment:
- During cheese ripening, the insoluble intact $\alpha_{s1}$- and $\beta$-casein curd matrix is progressively hydrolyzed by chymosin, plasmin, and starter enzymes into smaller water-soluble peptides, peptones, and free amino acids:
1. Water-Soluble Nitrogen (WSN Soluble Protein): Extracted with water or buffer at pH 4.6.
2. Total Nitrogen (TN Total Protein): Measured by the standard Kjeldahl method.
3. Ripening Index (Maturation Coefficient) (B): Calculated mathematically as:
\[ \text{Ripening Index} = \frac{\text{Soluble Protein}}{\text{Total Protein}} \times 100 \]
- In young unripened Cheddar, the index is $< 5\% - 8\%$; in mature aged cheese, it rises to $25\% - 35\%$, quantitatively indexing the extent and depth of ripening.

Step 3: Final Answer:
Hence, Ripening index is calculated as soluble protein Total protein x 100, matching option (B).