Factors Affecting Quality and Yield of Khoa

Fresh milk is usually preferred for production of good quality khoa, which has desirable organoleptic attributes and is suitable for making different types of sweets. The average yield of pindi khoa from standardized cow milk (fat 4.0% and SNF 8.6%) should be 18.5% and from buffalo milk (fat 6% and SNF 9%) 23%. The yield of other two types viz. Danedar and Dhap made from buffalo milk are usually 24% and 25% respectively. The various factors that affect the quality (here referred to organoleptic quality and suitability for sweets making) and yield of khoa are discussed as below:

 

i.Quality of Milk

Species of animal: Buffalo milk is preferred for preparation of khoa over cow milk due to following reasons:Organoleptic quality of buffalo milk khoa is much superior than cow milk khoa,because of its pleasantly sweet and creamy taste, soft body and texture with uniform grains. The colour of buffalo khoa is also whitish or creamy white, which is more attractive. On the contrary, cow khoa has salty taste because of presence of higher amounts of chloride (0.10% in cow milk as against 0.07% in buffalo milk) and its body is hard and dry due to low fat content. The free fat content, which provides some greasy appearance to the khoa and considered desirable attribute for sweet making, is also higher in buffalo khoa (about 60% of total fat) than cow khoa (lessthan 50% of total fat). The yield of buffalo khoa is also more as mentioned earlier because of higher total solids in it. Buffalo khoa is more suitable for making sweets than cow khoa.The organized dairy sector normally receives mixed milk. The quality and yield of khoa prepared from mixed milk falls in between that of buffalo milk khoa and cow milk khoa.

Use of colostrums: Colostrums milk has extremely poor heat stability and its chemical composition is different from normal milk. Khoa made from such milk has deep yellow colour and very big size clotted lumps unsuitable for sweets making.

Use of concentrated milk: The use of concentrated milk having more total solids requires less moisture removal for khoa making and thus exposed to heat treatment for less time. This results into lesser heat denaturation of milk proteins and under development of typical heated/cooked flavour in khoa. Therefore, khoa made from concentrated milk has somewhat bland flavour.Fat content in milk: A minimum of 4% fat in cow milk and 5% fat in buffalo milk is essential to prepare khoa conforming to legal (PFA) rules. The most pleasing aroma and taste in dairy products including khoa is attributed to butterfat. Therefore,the higher fat content in milk produces khoa of better quality not only in terms of flavour, but also the desirable body and texture. Khoa made from low fat milk possesses flat flavour and hard and dry body that lacks typical soft and mellowing characteristic.

Milk Acidity: The fresh milk produces khoa with good flavour and texture. Pindi khoa can only be made from fresh milk having acidity in the range of 0.14 to 0.16% as lactic acid. More than 0.17% acidity in milk produces khoa of grainy texture. The size and hardness of grains increases with the increase in acidity. However, for the manufacture of Danedar khoa, acidity upto 0.18% developed by addition of an acidulant is optimum. In addition to grainy texture, khoa prepared from high acidity milk, developed due to natural sourcing, has acidic/sour flavour. Such khoa is unsuitable for making of good quality sweets.Presence of adulterants/neutralizers: Adulteration of milk with water reduces the total solids contents of milk, thereby requiring more time for evaporation of this extra moisture to obtain khoa of desired solids. This is possible by exposure of milk to heat treatment for longer duration, resulting into development of brown colour in khoa. The yield of khoa will also be lowered in proportion to the amount of water added for adulteration of milk.

• Starch is added to milk to increase its total solids, particularly when adulterated with water. Khoa made from such milk is normally pasty with doughy taste.The yield however is higher in this case.

• Neutralization of high acid/sour milk is a regular practice in India. Use of neutralized milk produces khoa with improved texture having grains of very small size or no grains at all. But the flavour cannot be improved. Khoa made from neutralized milk has either salty or soapy or sour flavour, depending on the extent of neutralizer used and the level of souring (acidity) in milk before
neutralization. The moisture retention in khoa made from neutralized milk is higher and so also the yield.

 

ii. Speed of Stirring

The speed of stirring should be optimum. It depends on the type of machine/method.In case of traditional method, the optimum speed is about 100 rpm, whereas, in continuous system, it is slightly more (upto 200 rpm). The optimum speed of stirring prevents burning of milk solids and helps developing desirable body and texture in khoa. Low speed results into burning of khoa, whereas, the higher speed makes the product pasty and sticky.

 

iii. Temperature of Desiccation

To obtain good quality khoa, milk should be maintained at the boiling temperature till it reaches a pasty consistency and then lowered to about 95oC. Normally at this stage, the heating is discontinued. Continued heating at higher temperature at advanced stage of khoa making results in undesirable flavour (cooked) and texture (hard and dry). The colour of such product is also brown. Slow heating is not only more time consuming but also produces sandy texture and brown colour.

 

iv. Homogenization of Milk

Normally milk is not homogenized for khoa making. But under certain circumstances,such as use of recombined milk or for increasing the fat by adding butter oil or butter, homogenization of milk becomes essential. Khoa prepared from homogenized milk is brittle and lack cohesiveness. The moisture retention in such khoa is also more, which results into softness and higher yield.