Khoa | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Khoa Overview

• What is Khoa?
  • Khoa, also known as Mawa or Khava, is a key ingredient for making traditional Indian sweets, alongside chhana.
  • India produces approximately 300 million kg of khoa, valued at around Rs. 300 crore.
  • Its production is more prevalent in northern and western regions, with Uttar Pradesh contributing about 36% of the country's production.
• Khoa Definition:
  • Khoa is a partially dehydrated milk product created by heating milk in a karahi over direct fire with continuous stirring until it reaches a semi-solid consistency.
  • The resulting mass, known as khoa-pat, is solidified after being taken off the fire.
  • As per PFA Rules (1976), khoa is derived from cow, buffalo, goat, or sheep milk, with a minimum milk fat content of 20% in the final product.
• Indian Standard Specification for Khoa:
  • According to IS 4883-1960, khoa should have a maximum moisture content of 28.0% by weight and a minimum fat content of 26.0% on a dry weight basis.
• Khoa Composition:
  • The chemical composition of khoa varies based on the initial milk composition, concentration of milk solids, and handling processes.
  • Changes in these factors can influence the final composition of khoa.

Chemical Composition of Khoa

• Type of milk
• Cow: Moisture - 25.6%, Protein - 19.2%, Lactose - 25.5%, Ash - 3.8%
• Buffalo: Moisture - 19.2%, Protein - 17.8%, Lactose - 22.1%, Ash - 3.6%

Manufacturing Process

• Initial Boiling: Milk (preferably buffalo) boiled in a karahi over a non-smoky flame
• Concentration: Milk stirred vigorously until thickened and heat-coagulation of proteins begins
• Finalization: Mass reaches pasty consistency, dries up, and forms a compact mass known as khoa pat

Iron Content in Khoa

• High Iron Content: Iron scraped from karahi surface during manufacturing process
• Iron Concentration: Khoa contains significantly higher iron content (103-101 ppm) compared to normal milk (2-4 ppm)

Food and Nutritive Value

• Nutrient Concentration: Khoa contains milk solids in a highly concentrated form
• Nutritional Benefits: Rich in muscle-building proteins, bone-forming minerals, energy-giving fats, and lactose
• Vitamin Retention: Expected to retain fat-soluble vitamins (A and D) and water-soluble B vitamins from original milk

Trade Practices

• Batch Processing: Typically 2-3 kg of milk boiled per batch in a karahi
• Stirring Technique: Milk stirred vigorously to prevent sticking and scorching on the pan
• Concentration Process: Milk thickens and proteins coagulate, forming an insoluble concentrate
• Finalization: Khoa pat made by working mass into a compact shape, sometimes adding sugar

Note: Khoa is a concentrated dairy product with high nutritional value, created through a meticulous process involving milk concentration, protein coagulation, and final shaping.

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• Improved Method:
  • Equipment: A stainless steel jacketed pan/kettle is used for the improved method of khoa preparation, replacing the traditional karahi and open fire setup. This new equipment allows for better control over the dehydration process and uses steam or hot water for heating, eliminating smoke. An iron stirrer is typically employed for stirring.
  • Dehydration: The quality of khoa is affected by various dehydration conditions such as temperature, stirring speed, extent of dehydration, and batch size. To achieve the desired texture, milk is boiled until it reaches a pasty consistency, then cooled to 85 ± 3°C. Stirring should be done at a speed of 96-100 rpm, and dehydration is halted when the contents start to stick together.
• Quality of Milk: The type of milk used influences the quality of khoa. Buffalo milk is preferred due to its soft, loose body and smooth texture, making it ideal for high-quality khoa sweets. Buffalo milk also yields a higher amount of khoa compared to cow milk.
• Continuous Method:
  • Equipment: A continuous khoa-making machine was introduced in 1968 to address the limitations of the batch method. The equipment includes a steam jacketed drum heater, open steam jacketed pans, scrapers, and a power drive system.
  • Operation: In this method, milk is continuously heated and concentrated in the drum heater and open pans until a semi-solid consistency is achieved. Power-driven scrapers prevent scorching and burning of the milk. The finished khoa typically has a moisture content of 33-37%.

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The Process of Khoa Production

• The advantages of making khoa include the ability to produce it on a large scale under hygienic conditions, leading to significant savings in man-hours.
• Physico-chemical changes in milk during the conversion into khoa are as follows:
  • Change of state from liquid milk to solid due to dehydration.
  • Color transformation from a light to a more intense shade with a hint of brown.
  • Homogenization of milk fat due to the subdivision of fat globules through vigorous agitation at high temperatures.
  • Formation of fat due to the rupturing of fat globule membranes by the stirring action.
  • Heat-coagulation of milk proteins, with serum proteins coagulating due to heat and casein due to heat and concentration.
  • Supersaturation of lactose in khoa compared to milk.
  • Partial precipitation of milk salts by heat action.
  • Increase in iron content from 2 to over 100 ppm in khoa, mainly from the pan surface during production.

Market Quality of Khoa

• Market quality can be categorized into physical, chemical, and microbial qualities.
• Physical Quality:
  • The physical quality of khoa depends on the type of milk used and the manufacturing method.
  • Good quality khoa should have a uniform whitish color, a slightly oily or granular texture, and a rich nutty flavor.
  • It should be a compact mass of small, uniformly-sized granules without fat or water leakage.
  • When fresh, it should produce a smooth paste suitable for making sweets.
• Chemical Quality:
  • The chemical composition of khoa is influenced by the initial milk composition, milk solids concentration, and handling processes.
  • Khoa should not contain foreign constituents or be adulterated with starchy materials.
• Microbial Quality:
  • No specific standards for microbial quality are specified, but market khoa samples can contain various microbes from manufacturing, handling, and storage processes.
  • Even though milk undergoes heat treatment during khoa production, microbial counts can vary in market samples.

Summary and Elaboration

A tentative scorecard for khoa is outlined in Table 7, which includes items related to flavor, body and texture, color and appearance, and packaging, with a perfect score totaling 100.

Defects in Khoa and Prevention

• Defects in khoa stem from poor milk quality and incorrect production, handling, and storage methods.
• Preventing defects involves using high-quality milk, employing proper production techniques, and ensuring adequate handling and storage.

Packaging, Storage, and Marketing

Packaging

• Individual khoa portions are typically not packaged, but modern methods in the organized sector include the use of various materials like parchment paper, polythene film bags, laminated pouches, and tin-plate cans.
• In cities, khoa portions of different weights are wrapped in parchment paper and placed in cardboard boxes for sale.

Storage

• Khoa has limited shelf life at room temperature, but storing it at lower temperatures (5-10°C) can prolong its freshness.
• The storage duration varies based on temperature, with lower temperatures extending the shelf life.

Marketing

• Khoa is typically marketed shortly after production, either unpackaged or with basic packaging, depending on the market's proximity.

Uses of Khoa

• Khoa serves as a base and filler for various traditional milk sweets like gulab jamun, peda, barfi, kalakand, and pantoon.
• It can also be consumed on its own with added sugar.