Food Conservation

As mentioned in the introduction, fermentation has been used since ancient times to conserve and alter food. Also today, it is still applied on a very large scale for this purpose. A few typical examples are described in this chapter. The principle is similar in most cases. Lactic acid produced by bacteria protects the food from deterioration by inhibiting the growth of mold and other microorganisms. Most vitamins and nutrients of the food are preserved during fermentation. Three examples are discussed in more detail below The production of sauerkraut, soy sauce, and milk products (Table 9.3). 

TABLE 9.3 Examples of Food Items Produced by Fermentation 

Food products Ingredients Organisms Region/country 

Soy sauce Wheat, soy bean meal Lactobacillus, yeast East Asia 

Kefir Milk Streptococcus lactis, Lactobacillus bulgaricus South-western Asia 

TABLE 9 Examples of Food Items Pioduced by Fermentation 

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Quantitywise the next most important application is for food conservation in the sectors of meat, dairy products and margarine. Of the numerous other uses the dye, detergent and leather industries and for softening of water (ion exchanger) are worthy of mention. 

In addition to the sulfur-containing amino acids methionine and cysteine, inorganic sulfate, sulfur dioxide and organic sulfur compounds such glutathione, taurine and N-acetyl-methionine (to a lesser extent) are also important for the sulfur intake by sparing the required amounts of methionine and cysteine in the diet. The natural content of sulfur dioxide of food is far lower than the total sulfur content (Table 5.4). Sulfur dioxide is used for food conservation, and this in turn has led to the proposal of upper limit values for this sulfur compound (see Section 5.7 and Table 5.11). 

IX. Chlorides for feed and food conservation (e.g., monochloracetic acid)... 

Freeze-drying is a food-conservation process that leads to unique product characteristics. The removal of water from a frozen product under vacuum conditions results in a near-perfect preservation of shape and color, and leads to a sponge-like structure that allows a very fast water uptake during rehydration and... 

Transport properties of small molecules in amorphous polymer matrices play an important role in many industrial applications such as gas separation of mixtures, packaging applications ranging from food conservation to controlled drug and cosmetics release, to special coatings for protecting specific substrates from gases. 

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