Chemical Composition and Factors Affecting Khoa Quality and Yield

Khoa, a concentrated dairy product, is widely used in the Indian sweet and confectionery industry. Rich in proteins, minerals, fats, and lactose, it retains most of milk's nutritional components, including fat-soluble and water-soluble vitamins. Understanding the chemical composition and factors affecting yield and quality is essential for food manufacturers, consultants, and dairy processing professionals.

1. Chemical Composition of Khoa

As per FSSAI standards, all three varieties of khoa must have a minimum of 30% fat content on a dry matter basis. This high-fat composition contributes to its rich texture and taste—making it ideal for Indian sweet preparation.

2. Yield of Khoa in Dairy Processing

The yield is typically:

• 1 kg khoa from 4 kg buffalo milk
• 1 kg khoa from 5 kg cow milk

Yield is influenced by:

2.1. Type and Quality of Milk

Buffalo milk has higher fat and solids content, yielding more khoa than cow milk. Adulterated or diluted milk lowers output.

2.2. Moisture Content in Khoa

Higher moisture levels (e.g., in Dhap khoa) increase yield. Drier types like Pindi khoa yield less.

2.3. Handling Losses

Spillage and sticking during heating can reduce overall yield—highlighting the need for effective process engineering.

3. Factors Affecting Khoa Quality

3.1. Milk Quality and Type

Buffalo milk is preferred due to its higher emulsification, producing a soft, smooth granular khoa ideal for sweets.

3.1.1. Animal Species

• Buffalo milk yield: 21.6–23%
• Cow milk yield: 18.3–18.5% Cow milk khoa tends to be dry, sticky, and salty—less ideal for high-end sweets.

3.1.2. Fat Content

• Cow milk: ≥ 4% fat
• Buffalo milk: ≥ 5.5% fat

More fat = better body, texture, and sweet-making compatibility.

3.1.3. Acidity

Only fresh, sweet milk should be used. Sour milk results in bitter, coarse khoa unsuitable for sweets.

3.1.4. Additives & Adulterants

• Water lowers yield
• Colostrum causes yellowing and pasty texture
• Starch affects consistency and texture

3.2. Processing Parameters

a. Speed of Stirring

• Optimal: ~100 rpm in traditional methods
• Low speed: burnt khoa
• High speed: pasty, sticky khoa

b. Temperature of Desiccation

• Ideal: boil till paste, then cool to 88°C
• Overheating → dry texture, burnt flavor
• Slow heating → brown, sandy khoa

4. Impact of Processing on Milk

4.1. Physical State Change

Evaporation increases solids, decreases pH, and changes the milk from liquid to semi-solid form.

4.2. Cooked Flavor Development

Protein denaturation releases sulfhydryl compounds, altering flavor.

4.3. Casein Coagulation & Other Reactions

• Casein + whey protein forms a complex
• Calcium & phosphate shift to colloidal form
• Lactose becomes supersaturated
• Free fat increases (60% of total fat in buffalo khoa)
• Melanoidin pigment (Maillard reaction) causes browning
• Iron content increases due to utensils used (karahi and khunti)

5. Homogenization of Milk

Homogenized milk yields smoother khoa with:

• Less fat leakage
• Reduced browning
• Fewer patting tendencies

Ideal for manufacturers aiming for consistent product quality.

Conclusion

For those involved in dairy product development, food factory design, and sweet manufacturing, understanding the variables that influence khoa quality and yield is crucial. From milk selection and fat content to processing temperature and equipment hygiene, every step matters.

Food industry consultants, dairy technologists, and food processing consultants can apply these insights to design more efficient, hygienic, and profitable khoa production systems.