Everything you need to know about manufacturing Ghee. In this article we will discuss about:- 1. Process of Ghee-Making 2. Methods for Manufacture of Ghee 3. Final Temperature of Clarification 4. Cooling and Granulation (Crystallization) 5. Packaging and Storage.
Process of Ghee-Making:
Even today, the country or desi method of ghee-making contributes more than 90 per cent of India’s ghee production, the remaining quantity being manufactured by the organized sector of the industry which employs modern methods.
In the earlier days of dairy research in India, ghee attracted the maximum attention by virtue of its economic importance—more than two-fifths of the total milk production was converted into ghee at that time. Various workers have studied the traditional country (desi) process of ghee-making in India and their recommendations have been summarized in Table 11.25.
With the growth of the organized sector of the dairy industry and establishment of modern dairy plants, the emphasis shifted to conducting investigations on newer and larger-scale methods of ghee manufacture which could profitably be adopted for routine ghee production by these dairies. Various reports on ghee- making by creamery or desi-butter-ghee and direct cream-ghee processes appeared at that time; a few have also appeared in recent years.
Methods for Manufacture of Ghee:
Ghee may be prepared either from butter or cream. Butter may be either desi or creamery. The pre-stratification and continuous methods (under development) also use butter.
The flow diagram of the manufacture of ghee by these various methods, starting with milk, is given below:
1. Country/Desi Method:
Both makkhan and ghee are essentially prepared on a cottage industry scale at the producer’s household. The lot of makkhan, fresh or accumulated over a few days, is usually taken in a suitable open mud-pot or metallic vessel, and heated and stirred on a low fire to drive out the moisture.
When practically all the moisture has been removed, a stage judged by experience, further heating is stopped and the vessel removed from the fire. On cooling, when the residue has settled down, the clear fat is decanted into suitable containers. (Alternatively, the makkhan is converted into Kachcha ghee, which has a somewhat longer keeping quality than makkhan.) The traditional and improved desi methods have been compared in Table 11.26.
Desirable flavour, body and texture.
(i) Extremely small-scale production causing collection and marketing problems;
(ii) Low keeping quality and vitamin content.
2. Creamery Butter Method:
This is the standard method adopted in almost all organized dairies, where the raw material used is unsalted creamery butter, commonly known as ghee or white butter The butter is heated in an improved ghee boiler, which consists of a stainless steel jacketed pan (vessel) provided with a manual stirrer.
There may be provision for a movable, hollow, stainless steel tube, centrally bored through the bottom of the pan for emptying the pan-contents when required; alternatively, the pan may be emptied by providing a simple pan-tilting device. A steam control valve, pressure and temperature indicator, etc., are also provided in the boiler.
In the beginning, the solid mass of butter (which may be cut into small pieces to facilitate melting) is heated over a low fire and carefully stirred so that it melts. Later, the steam pressure in the jacket is raised so that the liquid mass starts boiling, with a removal of the water vapour from the pan-contents at a temperature of over 90°C.
This temperature remains constant as long as the moisture is being driven out. The contents are constantly agitated throughout the process of conversion of butter into ghee, to prevent scorching.
The scum which gathers on the top surface of the boiling mass is removed from time to time by a perforated ladle. Usually, there is profuse effervescence (1st), accompanied by a crackling sound in the early stages of boiling, but both gradually decrease if the moisture content is reduced.
When practically all the moisture has been driven out, the temperature of the liquid mass suddenly shoots up and the heating at this stage has to be carefully controlled. The endpoint is indicated by the appearance of effervescence (2nd), which is much finer than the first, together with a browning of the curd particles. At this stage a characteristic ghee flavour also emanates, and this is an indication that it has been heated sufficiently.
The final temperature of heating/clarification usually ranges from 110 to 120°C, depending upon the region. (In some parts of the country, it is finally heated to a still higher temperature, which yields a burnt or over-cooked flavour relished in those areas; a recent trend in other parts of the country is to use lower heating temperatures, around 107°C.)
After cooling and sedimentation, the ghee is filtered through a muslin cloth so as to separate it from the sediment-known as ghee-residue (consisting mostly of burnt casein). It then goes on for granulation and packaging.
Saving in labour, physical exertion and exposure to uncomfortably high temperatures and humidity during actual ghee making compared to the direct-cream heating method (because a much lower quantity of water has to be removed).
3. Pre-Stratification Method:
Clarification of butter into ghee by country or creamery methods has certain obvious demerits. Thus, in country methods, there is a much greater possibility of obtaining a finished product characterized by an over-heated and smoky flavour.
In the creamery method, as also in the country method, the high acidity of the raw material (especially true of makkhan) at high clarifying temperatures, makes the product greasy and also reduces its shelf- life. Research work has led to the evolution of a modified technique capable of yielding a higher grade product at lower cost of clarification.
When butter is left undisturbed at a temperature of 80-85°C for 15 to 30 minutes, it stratifies, i.e., separates into 3 distinct layers, viz., a top layer of floating denatured particles of curd, a middle layer of fat, and a bottom layer of buttermilk. This separation into layers has been called pre-stratification.
The bottom layer of buttermilk contains 60-70 per cent of solids-not-fat and also over 80 per cent of the moisture originally present in the butter. The buttermilk is mechanically removed without disturbing the top and middle layers. Afterwards, the temperature of the remaining two upper layers (of denatured curd and fat) is raised to the usual clarifying temperature of 110-120°C.
(i) Economy in fuel consumption as compared to direct clarification;
(ii) Production of ghee with a lower acidity and longer shelf-life (acid removed in buttermilk).
Desi butter with a higher moisture content is likely to be more economical in its fuel consumption as compared to creamery or white butter by this method.
4. Direct-Cream Method:
In this direct-cream heating method, the cream usually obtained by normal separation of milk is heated in the same ghee boiler described for the creamery-butter method. The procedure for heating and moisture removal, final temperature of clarification, cooling and sedimentation, granulation and packaging also remain the same.
Overall economy in labour compared to the creamery- butter method, since one stage, viz., cream to butter, is eliminated.
(i) Lower percentage of fat recovery in ghee due to greater fat loss in ghee residue—the amount of which is higher in this method than by the butter methods;
(ii) Slightly greasy texture in ghee.
(i) As pointed out above, one of the important drawbacks of the direct-cream-ghee process is a lower percentage recovery of ghee as compared with the creamery-butter process. This is because ‘normal’ cream (40-50 per cent fat) contains much more solids-not-fat (about 4.5 to 5.5 per cent) than desi or white butter (1 to 1.5 per cent).
This higher solids-not-fat content in cream contributes to a larger ghee-residue, which in turn causes a greater fat loss in the same. Earlier workers have shown that the non-fatty milk solids of cream, can be reduced by what has been termed the ‘cream washing’ process. This process consists of diluting the cream with lukewarm water (40°C) equal to the volume of the original milk.
After thoroughly mixing it by gentle stirring, the diluted cream is then separated without altering the conditions of normal cream separation. This washed cream contains 1-2 per cent solids-not-fat. When converted into ghee in the usual manner as indicated above, it gives a higher yield.
However, the ghee has a flat flavour, although the product also has a longer shelf-life. Artificial ripening of the washed cream with lactic starter to an acidity level of 0.20 per cent lactic, or acidification of the cream with citric acid to the same level prior to clarification as above, improves the flavour of the finished ghee.
(ii) An alternative to cream washing is the use of plastic cream, containing 65-85 per cent fat and a very low solids-not-fat content. This requires a special cream separator called a plastic cream separator. It is understood that a few ghee manufacturers in India have been using the direct-cream heating method and plastic cream for their routine production.
5. Continuous Method:
This is under development.
(i) To manufacture ghee on an industrial scale as a continuous process, to ensure uniform quality, and greater economy.
(ii) To reduce human labour, drudgery and fatigue by introducing as much automation as feasible or desirable under Indian conditions.
(i) Suitability for large-scale handling;
(ii) Utilization of machines for a large number of production- processes feasible;
(iii) Uniform demand on services;
(iv) High fat recovery;
(v) Possibility of in-place cleaning;
(vi) No stirring, no scraping and no laborious effort on the part of the ghee operators required.
Comparison of the Different Methods:
This has been shown in Table 11.27.
D.C. means direct clarification.
Final Temperature of Clarification of Ghee:
In general, a temperature range from 110 to 120°C is preferred. However, the final temperature to which ghee is heated during manufacture depends upon the region of the country; normally the temperature is around 110°C (or below) in north India and 120°C (or even higher) in south India.
A lower heating temperature improves the colour but decreases the keeping quality of the ghee obtained due to its greater residual moisture content; a higher temperature, on the other hand, tends to reduce the vitamin A content (with acid butter), and darken the colour, but increases the keeping quality of the finished product.
Cooling and Granulation (Crystallization) of Ghee:
Granularity in ghee is considered by the average Indian buyer to be an important criterion of quality and even purity. It may be pointed out that the partly granular form assumed by ghee is primarily due to a certain content of glycerides of higher-melting saturated fatty acids, especially palmitic and stearic. In this regard buffalo ghee, which is usually more saturated, crystallizes more effectively than cow ghee.
The desi method produces large crystals in ghee. On the other hand, the ghee obtained by creamery-butter on direct-cream processes need not necessarily have large crystals. It has been observed that heating ghee to 60-100°C, followed by rapid cooling, yields small grains in ghee; however, if the above ghee is held for crystallization at a temperature about 1°C above the melting point of ghee (cow ghee—29°C; buffalo ghee—31°C), a large number of big grains result.
Cold storage of ghee should be avoided, since it leads to a loss of granularity and the development of a waxy consistency in the stored product.
Packaging and Storage of Ghee:
Since milk fat is susceptible to deterioration due to exposure to light, air and metals, ghee (which is made up almost entirely of milk fat) should be properly packaged promptly after production so as to retain its initial flavour and nutritive value; it should also be properly stored so that its body and texture do not deteriorate.
The various problems of ghee-packaging have also been highlighted:
(a) Selection of Container:
The container is selected on the basis of the following considerations:
(i) Non-toxic and non-tainting character;
(iv) Resistance to rough handling.
Based on the above criteria, tin-containers are the obvious choice. They are also impervious to the action of light and air. The tin-containers should, however, be new and free from any trace of rust. They should preferably have a minimum tin-coating weight corresponding to 50 ETP (electrolytic tin plate).
Since the cost of tin containers has been rising steadily, cheaper plastic containers have appeared in the market. They are being tested to determine their suitability for the packing and storage of ghee.
(b) Size of Containers:
Most ghee is at present packed in 16 kg. containers for retail sale, which it may take two to three weeks to dispose of. In such large containers, the moisture in ghee tends to gravitate downwards. Thus the lower layers of ghee are likely to deteriorate because of an increase in the peroxide value and acidity. Hence for retail sale, ghee should be packed in smaller-sized containers with a capacity of not more than 4 kg. each.
(c) Filling and Sealing:
Since air (oxygen) exerts an adverse effect on the quality of ghee during storage, the tin-containers should be filled to the brim, with no air gap. If the ghee is filled while hot there is usually enough dissolved air to cause appreciable oxidative spoilage.
The use of vacuum-packaging in an inert atmosphere may be effective, but is prohibitive in cost. Under the circumstances, the next best alternative is to pack the ghee at a suitable temperature, viz. 30-32°C (which will limit the dissolved air to the minimum possible), up to the brim of the container, and then seal it. Only rust-free containers and lids should be used.
The storage of ghee in different types of containers has been studied. It is well known that the development of an oxidized flavour or tallowiness in ghee is accelerated at higher storage temperatures, especially with ghee which has an appreciable initial acidity. Under the existing conditions of handling, the storage temperature of ghee may vary from 5 to 38°C throughout the country depending on the season of the year.
Although refrigerated storage of ghee delays acid-development and thereby prolongs its keeping quality, it renders the stored product greasy and pasty. A storage temperature of around 21°C is usually recommended.