Common deffcts in Butter and their Control

Good quality butter should possess a mild, sweet, clean and pleasant flavour and a delicate aroma. The aroma of butter is due to the composite effect of flavour of milk fat and serum. The body & texture of butter should be evaluated at 7-13°C and it should be firm, smooth and waxy. It should look like a compact mass of closely-knit butter granules. Water droplets and air cells in proper amounts should be uniformly  distributed and closely bound. Ideal butter should cut and spread easily and readily. There should not be any visible water droplets. The colour of butter may vary from light creamy white to dark creamy yellow or uniform light straw colour.

In case of decrease in quality it is difficult to determine which of the three factors,like, chemical, microbial and enzymatic reactions is responsible. In general the development of defects can be checked by observing highest possible hygiene in the plant, using packaging material of hygienic quality, uniform distribution of moisture as fine droplets in butter, by proper working, avoiding exposure to light, humidity and external environment, avoiding contamination with metals and their salts, and microorganisms.

Defects in butter, however, may develop due to use of low- grade milk or cream and faulty method of production, packaging and storage. The common defects in butter, their causes of development and preventive suggestions are discussed below.

 

i. Flavour Defects—Causes and Prevention

Acid flavour: It is recognized by sour taste of butter on the tip of the tongue. It is caused by the use of acidic or under-neutralized cream for butter making. Contamination with bacteria, presence of water, air, light, enzymes and some metals can accelerate the defect. Use of fresh and sweet cream or properly neutralized cream may overcome the defect.

Alkaline or neutralized flavour: Use of over neutralized cream results in butter having flavour of neutralizer. This flavour defect can be eliminated by using optimum quantity of proper neutralizers.

Bitter flavour: It resembles the taste of quinine. It persists as a distinct lingering aftertaste even after the sample has been removed from the mouth. Use of Cream obtained from milk of cows/buffalo fed on some bitter weeds or from milk, which has not been heated enough to destroy lipase enzyme activity is the cause for development of the defect. The control measures include rejection of milk from milch animals fed on bitter weeds and heating of milk above 37°C to destroy lipase activity in milk and storage of cream at 5°C to check the growth of proteolytic bacteria and other organisms during storage of cream.

Cheesy flavour: The flavour of butter resembles that of the cheddar cheese. This is again the result of the growth of proteolytic microorganisms leading to breakdown of casein in cream. This can be eliminated by storing cream at 5°C to control the growth of proteolytic organisms.

Cooked flavour: This flavour is easily recognized but is less objectionable. It is caused by overheating of cream or milk at any stage of processing. Therefore following the recommended time-temperature combination for processing of milk or cream can eliminate the defect.

Feed flavour: It is similar to the smell of hay or silage. It results from the cream obtained from milk possessing this flavour defect. Therefore, grading of milk should be done carefully and such milk with this flavour defect should not be used for cream production. Vacreation process used for pasteurization may also help to control the defect.

Fishy flavour: Butter may develop a flavour and aroma similar to cod liver oil, fish-meal or codfish. It commonly develops in high acid salted butter in the presence of metals like copper and/ or iron. Use of sweet cream for butter making and avoiding possible source of metallic contamination are the preventive methods for the defect.

Flat flavour: Butter lacks characteristic buttery flavour. Butter, which, has low diacetyl content, low salt content and has been excessively washed may exhibit this flavour defect. Ripening of cream with butter culture to proper acidity, using correct amount of salt and giving optimum washing to butter are the suggested control measures.

Rancid flavour: It is a pungent and very undesirable flavour, caused by the hydrolysis of fat due to the action of lipase in milk or cream. It resembles decayed meat. Inactivation of lipase enzyme by giving proper heat treatment to milk and cream helps to control defect.

Oxidized/Metallic/Tallowy flavour: It resembles tallow. It is caused by oxidation of fat due to direct exposure of milk, cream or butter to sunlight and contamination with copper or iron. This defect can be prevented by storage of milk, cream and butter in opaque containers made of tinned or aluminium alloy, stainless steel, etc.

Stale flavour: Butter lacks freshness. This is caused by holding the butter for a long period at low temperature or for short period at high temperature. Use of cream stored for long period also results in this defect. Therefore, avoid storing cream or butter for longer period and use correct temperature of storage to control this defect.

Yeasty flavour: It is identified by the development of typical fruity, vinegar like aroma. It results from the use of old and yeasty cream for butter making. Use of fresh sweet cream and storage of butter in hygienic condition helps to eliminate this defect.

 

ii. Body and Texture Defects - Causes and Prevention

Crumbly or Brittle body: Lack of cohesiveness, dryness, rough surface and difficulty in slicing indicate crumbly body defect. It is caused by seasonal changes in the composition of fat, sudden chilling or under-working of butter. To overcome this problem, adequate working of butter, controlled cooling and ageing of cream, proper churning and washing of butter are the suggested measures.

Greasy body: Excessive smoothness and quick melting in the mouth indicate greasy consistency of butter. This defect is caused by over-working and high temperature of wash water. Corrective measures include adequate working and use of wash water at recommended temperature.

Gummy body: Butter does not melt readily in the mouth. It is caused by the presence of high melting triglycerides (solid fat) in high proportion in butter. This requires elimination of feeds containing high melting point fats to the milch animals to control the defect.

Leaky body: Butter showing moisture droplets when a sample is drawn indicates this defect. Under-working of butter, excessively high temperature of churning and wash water, over-working of butter, insufficient cooling and ageing of cream results in this kind of defect. The control measures include adequate working, optimum churning and use of correct temperatures at various stages of butter making.

Mealy body: Butter does not cut well and spread. Incorrect neutralization of high acid cream with lime and oiling-off of fat during butter making cause this defect.Use of correct neutralization procedure and neutralizers and avoiding oiling-off by using correct temperatures at processing steps can prevent the defect.

Spongy/Weak: This defect is indicated by quick melting of butter and its excessive softness. Inadequate ageing and cooling, high temperature of churning and high proportion of low melting fat in butter are the causes of development of the defect.Hence proper ageing and cooling of cream and churning at optimum temperature can prevent the defect.

Sticky body: Butter appears to be dry but sticks to the butter trier (the device used for drawing of butter sample). Overworking of butter causes this defect and therefore, requires controlled working under proper temperature.

Gritty body: Presence of undissolved salt particles indicates gritty body of butter.Proper salting method, use salt after grinding and avoiding long storage of butter can prevent this defect.

 

iii. Colour Defects - Causes and Prevention

Mottled colour: Mottled colour is indicated by the presence of spots of lighter and deeper shades of yellow colour in butter. It is caused by inadequate washing of butter grains, improper incorporation of salt and inadequate working of butter. The control measures include adequate washing, proper incorporation of salt and adequate working of butter

Streaky colour: Presence of distinct waves of different shades of yellow colour in butter indicates the defect. Streaky colour defect is caused due to un-even and incomplete working of two or more lots of butter. It can be controlled by properly and evenly working the butter.

Dull/pale colour: Over-working of butter may result in the development of a dull colour. Therefore, working should be optimum to control the defect.Prime rose or high colour surface: This colour defect is indicated by deepening of colour of the exposed surface of butter. It requires proper packaging to cover the entire surface of butter to control this defect.

Mould discolouration: Growth of moulds on the surface of butter produces a range of colours. Proper packaging and storage of butter in rooms at controlled temperature and humidity are the means to control the defect.