[Intermediate moisture foods: polysaccharide and protein gels].

The aim of this study was to prepare concentrated foods (20-40 p. 100 water), edible as such, chemically and microbiologically stable, nutritionally balanced, and which could be used as meal substitutes (travel, camping, snacks, etc.). With high methoxyl pectins, it was possible to obtain a pectic gel (pH 3,5), similar to a fruit jelly, but containing 20 p. 100 d.w. protein, and less sucrose. Water activity (Aw) was 0,75-0,78, for a 25 p. 100 water content, as a result of adding glucose syrup and sorbitol. After 4 months storage at 20 or 38 degrees C in aluminium pouches, no mold growth was detected (even following prior inoculation) nor practically any change in flavor, texture of Aw. With low methoxyl pectins, gel foods richer in water (35 p. 100), softer, less acid (pH 4,3) and containing even less sugars have been prepared (26 p. 100 d.w. protein, 35 p. 100 carbohydrates, 15 p. 100 lipids). Aw was lowered to 0,84 by adding humectants (sucrose, glycerol, sorbitol, citric acid, sodium citrate and chloride). Starch gels (40 p. 100 starch/d.w.), of pH less than 4,5, containing proteins and lipids, were flavored with vegetale powders. For 30 p. 100 water and with humectants, Aw was 0,84-0,88. The texture changes more or less favorably with time according to the nature of the starch used. Using the technology of processed cheeses, protein gels were made with either of the following characteristics: 1. A reduced Aw (0,86, for 38 p. 100 water) by adding humectants, but with a soft texture similar to that of a processed swiss cheese; 2. The same reduced Aw, with a starch content of 26 p. 100/d.w., and a harder texture, comparable to that of Emmenthal cheese.