Factors Affecting Quality of Chhana

Cow milk is preferred for chhana making because it yields soft and spongy body and smooth textured product, which is suitable for making chhana based sweets.Buffalo milk, because of many inherent differences in physico-chemical make-up than that of cow milk, poses, many technological problems in preparation of chhana and chhana based sweets. The quality of chhana depends mainly on the initial composition of milk, type and quality of milk, the conditions of coagulation, the technique of straining/pressing and the losses of milk solids in the whey.

 

i.Type of Milk

Cow milk produces chhana with moist surface, light yellow colour, soft body, smooth texture and mildly acidic flavour. Cow milk chhana is more suitable for Bengali sweets preparation than buffalo milk chhana; the latter being hard in body and coarse in texture, besides whitish in colour and a greasy surface. Sweets particularly rasogulla prepared from buffalo milk chhana are comparatively hard, coarse and less spongy. Goat milk can also be converted into acceptable quality chhana, which is suitable for sweet preparation.

 

ii.Quality of Milk

Minimum fat level of 4 per cent in cow milk and 5 percent in buffalo milk is necessary for producing good quality chhana. The low fat milk results in a hard body and coarse texture in chhana, whereas higher fat level is also not desirable as it produces greasiness and stickiness in the chhana sweets. For manufacture of good quality chhana sweet milk (fresh milk is the best suitable raw material, as developed acidity or sour milk tends to produce too acidic flavour and bitter taste, which makes it unsuitable for preparation of sweets). The addition of neutralizer to acidic milk,however, helps in obtaining chhana which can be satisfactorily used for making sandesh of an acceptable quality. The adulteration of milk with starch results in a gelatinous mass on coagulation, which is undesirable for sweet making. The mixing of colostrum in milk tends to produce a weak and pasty body and texture in the coagulated mass, which exhibits its unsuitability for sweet making.

 

iii. Type and Strength of Coagulant

The body and texture of chhana is influenced by the conditions of coagulation such as pH of coagulation, strength of coagulating solution, type of acid, speed with which the milk is stirred during coagulation and temperature and time of coagulation.In order to obtain desirable body and texture milk should be sufficiently heated to near the boiling temperature for better protein-to-protein interaction. The optimum pH of coagulation of milk is around 5.4 and the temperature of coagulation is about 82oC. The coagulation of milk should be effected within one minute with gentle stirring. A satisfactory strength of the coagulating acid solution is 1-2 percent. Lactic acid tends to produce a granular texture, which is desirable for rasogulla making,whereas, citric acid tends to produce a pasty product, which is suitable for Sandesh manufacture.

Generally organic acids like citric, lactic or their salts (calcium lactate), lemon juice and sour whey are used as coagulants. Sour whey with about 0.9 percent acidity is most widely used for chhana making. Calcium lactate is another commonly used coagulant.The concentration of coagulant solution is also an important factor which affects the quality of chhana. Low acid strength (0.5 percent) results in very soft body and smooth texture suitable for rasogulla but unsuitable for sandesh making, while high acid strength (8 per cent) results in hard body and less smooth texture, suitable for sandesh making but not for rasogulla. The optimum strength of coagulant solution should be between 1 to 2 per cent citric acid or lactic acid to produce good quality chhana suitable for making both kinds of sweets. To get a satisfactory quality chhana from buffalo milk, 1 per cent citric acid solution or 0.5 per cent lactic acid solution is recommended. Sour whey of 0.9 per cent acidity is suitable for chhana making. Six per cent calcium lactate solution produces most satisfactory quality chhana.The amount of coagulant required to achieve optimum coagulation depends upon the type of milk as also on its acidity and buffering capacity. Usually, 2.5 to 3.5 g of citric acid or 3.0 to 3.9 g of lactic acid per litre of milk is necessary for complete coagulation. The requirement of acid is lower in case of buffalo milk. Nearly 600 ml of sour whey is needed to produce suitable quality chhana from 1 litre of milk. The quantity will largely depend upon the extent of acidity developed in the sour whey.About 6 to 12 g of calcium lactate is required per kg of milk for coagulation, depending on the coagulation temperature.

 

iv. Coagulation Temperature

Chhana of satisfactory quality from cow milk can be obtained at a coagulation temperature of about 82oC. The optimum coagulation temperature for making chhana from buffalo milk is around 50oC. The amount of coagulant required for completing the coagulation of milk is increased with the lowering of coagulation temperature. As the coagulation temperature decreases, the moisture retention in chhana increases leading to its softer body and smoother texture.

 

v. pH of Coagulation

The optimum pH for chhana making from cow and buffalo milk is 5.4 and 5.7 respectively. The pH of coagulation principally regulates the moisture content and the body and texture which are best obtained at the above pH. An optimum pH of 5.35 has been reported when making chhana from cow milk using calcium lactate as coagulant. Higher speed of stirring during coagulation reduces the moisture content in chhana and increases its hardness, whereas with lower speed the reverse holds true. Slow stirring (40-50 rpm) is preferred to avoid foam formation.

 

vi. Method of Straining

The method of straining of coagulated mass effect the body and texture of paneer,moisture retention and solids recovery in chhana. The coagulated mass should be collected in fine cloth and hung to remove moisture.In case of chhana external pressure is not applied for removal of moisture from the coagulated mass. Method of straining is an important factor which affects the body and texture of chhana by influencing the moisture retained in it. In general two types of straining is employed viz. immediate or delayed. Immediate straining is carried out by promptly gathering the coagulated mass and tying it up in a piece of fine cloth and then hung up for draining out the whey and cooling the chhana. In case of delayed straining process, the coagulated mass is left in the whey either as such or loosely enclosed in a piece of cloth, so as to cool it to ambient temperature and thereafter it is hung for removal of whey. The delayed straining results in more retention of moisture in chhana as compared to immediate straining method. Delayed straining produces a comparatively soft and smooth texture chhana than immediate straining.Higher moisture, increased yield, improved recovery of milk solids and lower hardness in chhana is obtained when delayed straining is employed. Chhana made by delayed straining process is useful for rasogulla making and is particularly recommended for buffalo milk chhana production.