Butter salting process

Dairy products comprise substantial part of total sodium intake in the diet. Various types of cheeses, ayran and butter contain varying levels of salt and particularly cheeses have high levels of salt in their composition. Butter is essentially a water-in-oil emulsion, comprising of more than 80% milk fat, but also containing water in the form of tiny droplets, perhaps some milk SNF, with or without salt (sweet butter).

According to PFA (Prevention of Food Adulteration) food law, table /creamy butter should contain not more than 3% common salt. It should not contain any preservatives except common salt. Salted butter is produced by adding salt in the unsalted butter in the butter making process.

During butter making process, chilled water at approximately 5 °C is used to harden and control the size of these grains, as well as to remove the traces of buttermilk.

Salt may be added dry or in the form of brine as a final wash. The addition of brine (10% solution) to butter grains has been used to reduce the need for chilled water.

• If the butter is to be salted, in batch process, salt (1-3%) is spread over its surface.
• In the continuous butter maker, a salt slurry (10% concentration) is added to the butter.

The butter grains are ‘worked’ to expel excess moisture, create an even, fine distribution of water droplets, and produce a close textured, evenly colored product.

Salt, as wells as its role in the taste, preserves the product and extends the shelf-life - the average shelf-life of salted butter is five months when refrigerated while this period is three months in unsalted butter.

Salted butter enhances the taste of toasts and other foods as the salt bring out not only the butter flavor, but the other flavors that are in the food.
Butter salting process

Aging and crystallization of butter

Aging of cream is an important process to manage production time and to produce butter with consistent quality.

Hardness of butter can be customised by changing the aging parameters of the cream. Cream can be aged at higher temperature with low agitation without altering the butter hardness.

Fat crystallization in cream during aging is an important process that affects churning time, texture, and mouthfeel of butter. During the aging process, liquid oil in the milk fat globules in cream start crystallizing. The amount and size of crystals in cream can be controlled by processing conditions such as crystallization temperature, cooling rate, and agitation rate.

Crystallization of milk fat in cream is essential for butter making to form a continuous fat network during churning. The crystals bind the liquid fat to their surface by adsorption.

The crystallization mechanism relevant for crystallization of milk fat is the nucleation and growth mechanism. Nucleation consists of primary and secondary nucleation. Primary nucleation can occur homogeneously or heterogeneously.

Homogeneous nucleation occurs when nuclei are formed without pre-existing crystals, whereas heterogeneous nucleation occurs when nuclei are formed by foreign substances, such as air bubbles, dirt, or a scratch on the wall. Secondary nucleation is induced by preexisting crystals.
Aging and crystallization of butter

Ripening process of butter

The thermal treatment of the cream, also known as ripening, is the most time-consuming step in butter production; however, it governs the crystallization of the fat and thereafter the consistency of the butter.

Ripening is needed for production of desirable flavor and aroma in butter; also facilitates exhaustive churning. Ripening improves the keeping quality of un-salted butter but reduces the keeping quality of salted butter.

Ripening involves addition of starter culture, mixing it thoroughly and storing the cream (incubating) at controlled temperature. Traditionally cream for ripened cream butter is fermented by selected lactic acid bacteria, which produce lactic acid from lactose and diacetyl (principal flavouring component in ripened cream butter) from citric acid.

Starter culture consisting of a mixture of both acid producing (Streptococcus lactis, S.cremories) and flavour producing (S.diacetylactis, Leuconostoc citrovorum and/or Leuc. dextranicum) organisms is added. Amount of starter added depends on several factors and usually ranges between 0.5-2.0 percent of the weight of the cream.

The cream is ripened to pH 5.5 at 21°C and then pH 4.6 at 13°C to arrest further acid development. Most flavor development occurs between pH 5.5 - 4.6. Biosynthesis of diacetyl is not sufficient above pH 5.5.

The colder the temperature during ripening the more the flavor development relative to acid production. Ripened butter is usually not washed or salted.
Ripening process of butter

Butter processing: Pasteurization

The pasteurization of cream for butter making has for its primary object the elimination of the normal bacteria of the cream to enable the butter maker by controlling the ripening of the cream to secure a uniform product.

Butter processing begins with the clarification and separation of milk. The cream is cooled and kept in a transitional storage tank where the fat content is analyzed, and if necessary adjusted to the desired value.

Cream with a concentration of 30 to 45 percent milkfat (depending on the method of churning) is then pasteurized and cooled.

For vat pasteurization the cream is normally pasteurized at 74° C for 30 minutes; for the high temperature short time method cream is pasteurized at 85° C for 15 seconds.

The high temperature is needed to destroy enzymes and micro-organisms that would impair the keeping quality of the butter and to help lengthen butter’s shelf life.

Pasteurization of cream for making ripened cream butter is commonly carried out at higher temperature than for sweet cream butter e.g., 90-95° C for 15 or 105-110° C with no holding. Severe heat treatment denatures whey proteins, particularly lactoglobulins, exposing-SH groups which act as antioxidants and can enhance starter growth.

Several factors are involved in the determination of this temperature, among the most important of which are the uniform destruction of a large proportion of the bacteria of the cream; the destruction of the enzymes inherent in the milk; the avoidance of imparting scorched, metallic, or other undesirable flavors to the cream; and the possible increased loss of fat in the buttermilk.

Pasteurization causes the fat in the fat globules to liquefy. And when the cream is subsequently cooled a proportion of the fat will crystallize. If cooling is rapid, the crystals will be many and small; if gradual the yield will be fewer but larger crystals.

By modifying the cooling program for the cream, it is possible to regulate the size of the crystals in the fat globules and in this way influence both the magnitude and the nature of the important continuous fat phase.
Butter processing: Pasteurization

Preparation for butter production

Butter is a dairy product made by churning fresh or fermented cream or milk. Conversion of milk fat into butter is a very old way of preserving milk fat.

Worldwide, butter is made from a variety of animal milk including cow, goat, camel, buffalo and sheep. The most dominant source for production of butter today is bovine milk.

The buttermaking process involves quite a number of stages. The continuous buttermaker has become the most common type of equipment used.

Fresh milk is first separated into skim milk and cream and the cream is then used to make fresh butter. Milk with a high fat content (Table 2) gives a higher butter yield. Cream is separated from milk by centrifugation. Normally, the raw milk is preheated to above 40 C to ensure that all of the fat is in a liquid state so that the milk-fat globules are less susceptible to shear damage.

The cream should be sweet (pH >6.6, TA = 0.10-0.12 %), not rancid and not oxidized. The cream is cooled and kept in a transitional storage tank where the fat content is analyzed, and if necessary, adjusted to the desired value.
Preparation for butter production