CHEESE TECHNOLOGY

Module 5. Cheese additives

Lesson 11
CHEESE ADDITIVES AND PRESERVATIVES

11.1 Introduction

In addition to certain major processing aids such as starter bacteria, internal and external molds and coagulants, various additives used in the manufacture of cheese serve as manufacturing aids. Some of them also prevent fermentation faults (e.g. late blowing).

11.2 Salts to Restore the Calcium Balance in Milk

Calcium in milk is present as soluble, colloidal and complexed forms in a very delicate balance. Successful coagulation depends on this balance of calcium. Sometimes the balance among the three different forms is disturbed due to heat treatment, cooling or disturbances in milk itself (colostrum, late lactation, mastitis). In such cases it has become a common practice to add calcium salt, usually calcium chloride, to milk. This is especially necessary when some of the vegetable or microbial coagulants are used. Other calcium salts which can be added include calcium lactate and calcium hydroxide. They are in the form of a solution. Bovine milk contains 0.123% calcium while maximum clotting advantage occurs at a concentration of 0.142%. Therefore, addition of 0.02% calcium chloride is suggested. If excess is added, α_s casein-қ casein complex dissociates and the α_s casein no longer has the protection from the қ casein and a precipitate forms. Slightly less calcium chloride will produce a harsh inflexible curd. Rarely is more than 0.02% of calcium chloride needed for satisfactory coagulation even when using highly heated milks. Retention of too much calcium chloride, apart from producing a hard unyielding curd, produces a cheese which is bitter in flavor and with a harsh body.

11.3 Salts Inhibitory to Undesirable Organisms

Salts like potassium nitrate, sodium hydrogen carbonate, calcium carbonate, mono-sodium dihydrogen phosphate and nisin are added to arrest the growth of undesired microorganisms. These are commonly added in some of the less acid curd cheese like Edam, Gouda etc. mainly to prevent the growth of gas producing organisms which cause ‘blown’ defect in cheese. Nitrate in combination with salt has been used to control the gas forming butyric acid bacteria and at the same time, it does not have any affect on the growth of lactic and propionic acid bacteria. But the use of nitrates in cheese is limited due to two main reasons:

1. Certain amino acids react with nitrite to produce color defects

2. Production of nitrosamines which are carcinogenic

Nisin may be used in processed cheese to inhibit the activity of gas producing organisms but not in natural cheese, because the bacteria present in natural cheese destroy the activity of nisin. Sorbic acid is used to inhibit the growth of yeasts, molds and some bacteria. However, its activity against bacteria is not as comprehensive as that against yeasts and molds.

11.4 Use of Common Salt (NaCl)

Salt normally used in cheesemaking is about 2% of the weight of the curd. Salt is added to cheese:

a. To suppress growth of unwanted micro-organisms,

b. To assist the physico-chemical changes in the curd,

c. To slow down the growth of the lactic acid and other types of unwanted microorganisms,

d. To give the cheese an appetizing taste.

Specification

Common salt contains 99.6% NaCl on moisture-free basis limits are given for alkalinity (0.03% Na₂CO₃), insoluble matter (0.03%), sulfide (0.3% Na₂SO₄), iron (0.001%), copper (0.002%), arsenic (0.0001%), lead (0.0005%), calcium (0.1%), and magnesium (0.01%) dried salts should pass completely through an 18-mesh sieve.

Effect of quality of salt on cheese:

1) Use of impure salts results in faulty color in presence of iron, copper and lead. The fault could be avoided by acidifying the brine to pH 5.0 with lactic acid.

2) Fine salts may increase the rate of loss of whey and thus protein and fat from the curd.

Effect of quantity of salts on cheese:

1) Exert an appreciable effect on growth of molds in blue veined cheese.

2) Low concentration stimulates most microorganisms and some enzymes.

11.5 Acidulants

The most common acidulant used in cheese making is lactic acid, which is produced in situ by lactic acid bacteria present naturally in milk. Pure defined cultures of lactic acid bacteria (LAB) can also be used. However, the use of acids for chemically acidifying the milk is also practised. Acids of food grade quality (e.g. lactic, glacial acetic, lemon juice, vinegar, D-glucono-delta-lactone, phosphoric) are used to increase the acidity of milk.

• Glacial acetic acid (12.5% concentrated acid @ 2.7% of milk) is used in Queso Blanco cheese and vinegar (0.03%) for mozzarella cheese manufacture.

• Lime juice is used in India to manufacture Bandal cheese, paneer and channa.

• D-glucono-delta-lactone when heated produces acid and it has been used for the production of acid in milk and curd. The cheese made by using this acidulant is bland and lacks flavor as no enzymes are formed in this process.

• Phosphoric acid (10% strength) is diluted @ 4 l in 40 l of water and then added to 1000 l of milk with vigorous stirring.

11.6 Colors and Bleaching Agents

The color of the product is an important factor in the consumer appeal of the product. It is a common practice to add extra color to pale colored milk to give cheese an attractive and appetizing appearance. The colors of importance in milk are riboflavin and carotenoids. Riboflavin is yellow in solution with a green-yellow fluorescence and tends to give curd a greenish tinge. However, most of this color is lost in whey as riboflavin is water soluble. Therefore, its effect as color in cheese is small. The deep yellow orange color due to carotenoids is more significant. As there is a large seasonal variation in color of milk, colors are added to obtain uniform color in cheese. Annato is, by far the most widely used color. It is extracted from seeds of a plant Bixa orellana in sodium hydroxide. The pigment in annatto is the acid bixin which, in the alkaline extract becomes norbixin. The color is composed of tints of yellow and red units, and in cheese, becomes a protein dye attached to the casein. Annatto is very susceptible to oxidation. Agents such as H₂O₂, air, -SH groups in ripening cheese and copper and iron act as catalysts in oxidation of annatto pigment. Thus, bleaching of the red color in patches in cheese is frequently found in poor quality, moist or contaminated curd.

Sometime it becomes desirable to bleach the color to meet the market demand particularly in traditional products. For example the customers expect Mozzarella cheese to be white as it is made from buffalo milk. In case cow milk has been used, it will yield a yellow product. In such cases bleaching agents may be added to milk. Benzoyl peroxide, H₂O₂ and other color masking agents are used for this purpose.

11.7 Flavors, Spices and Herbs

There are two groups of flavoring agents which are added to cheese:

(a) those which are added for imparting flavor to the cheese (herbs and spices)
(b) those flavors which are nutritive foods in their own right (ham, meats etc.), which are enclosed in the cheese which serves simply as a soft enclosing base.

Chopped herbs, or their juices, or dried crust semi powders have been used to impart flavor and aroma in cheese curds. The herbal mixes are incorporated in the raw cheese at moulding time before pressing, or are mixed with partially or wholly ripe curds pressed into shapes or containers. Spices which have been used include aniseed, caraway seed, cloves, cumin, cinnamon, ginger, nutmeg, pepper etc. Herbs used in cheese include mint, sage, lavender, chives etc.

11.8 Smokes

Certain cheeses are exposed to a smoke-charged atmosphere for smoky flavor development. It causes fat to melt and come out the surface of the cheese block, and no moisture to evaporate. Incorporation of smoke vapors containing phenolic substances has preservative effect and also impart typical flavor to cheese. Sometimes cheese is dipped in liquid condensed smoke.

11.9 Addition of Beverage

Alcoholic beverages, beers, wines and liquors have been added to the raw cheese curd or alternatively, the whole cheese has been immersed in the liquid. The mixing of flavors, vegetables, spices, meat, etc. seems to break with tradition to satisfy the taste of modern society particularly for snack foods.

11.10 Cheese Bases

The use of a bland cheese base along with a filling of herbs, vegetables and chopped cooked meats is probably a spillover from the use of processed cheese in the similar manner. The typical mixtures use cheese as a base, with the addition of lettuce, chives, onions, spinach, potatoes, carrots, chopped ham etc.