Abstract: The problem to be solved by the invention is to provide a food or a drink containing an acidic protein which has a favorable flavor with relieved astringency characteristic to a protein dissolved under acidic conditions to thereby broaden the flavor variety of protein-containing foods or drinks. The above problem can be solved by adding a water soluble polysaccharide, a water soluble basic salt, an alkali metal salt of an organic acid, a basic monosaccharide, a basic oligosaccharide or the like to a food or a drink containing a protein dissolved under acidic conditions to thereby relieve the astringency originating in the protein dissolved under acidic conditions.

Abstract: The problem to be solved by the invention is to provide a food or a drink containing an acidic protein which has a favorable flavor with relieved astringency characteristic to a protein dissolved under acidic conditions to thereby broaden the flavor variety of protein-containing foods or drinks. The above problem can be solved by adding a water soluble polysaccharide, a water soluble basic salt, an alkali metal salt of an organic acid, a basic monosaccharide, a basic oligosaccharide or the like to a food or a drink containing a protein dissolved under acidic conditions to thereby relieve the astringency originating in the protein dissolved under acidic conditions.

Abstract: The present invention is intended to provide acidic gel foods containing soybean protein to diversify means of taking soybean protein in daily eating habits. Using the acid-soluble soybean protein as specified in the description, an aqueous solution or an alcohol-containing aqueous solution of the protein is adjusted to pH 3 to 4.5. Then an acid having 2 or more acid groups per molecule or its salt or a salt of another acid is added thereto and the mixture is heated to form a gel. Thus, acidic gel foods including a jelly-like food favorable as a food can be obtained.

Abstract: It is intended to provide an acidic polar solvent containing protein which contains dissolved soybean protein at a high concentration and shows a high stability over a long time without adding a stabilizer or decomposing the protein. It is also intended to provide a protein-containing food of the gel type such as an alcoholic drink or an alcoholic jelly. A polar solvent in the state of a solution or a gel, in which soybean protein is not dispersed by adding a stabilizer or the like but stably dissolved, can be provided by employing acid-soluble soybean protein in a polar solvent in the state of being dissolved therein.

Abstract: It is intended to provide a soybean protein material which is excellent in solubility, stability, emulsifying properties and gel-forming properties under acidic conditions and thus advantageously usable in acidic foods, its production process, and acidic foods using the soybean protein material. A solution containing soybean protein is subjected to a treatment for eliminating or inactivating polyanionic substances contained therein and/or adding a polycationic substance and then heated at above 100° C. under acidic conditions. Thus, a soybean protein having a high solubility under acidic conditions and thus being appropriately usable in acidic foods can be obtained. By using this protein, protein foods in an acidic region can be provided. Further, by combining the above-described treatment with a protease-digestion treatment, a soybean protein hydrolysate having a high solubility in an acidic region can be efficiently obtained.

Abstract: It is intended to provide a food or a drink with a favorable flavor which has an acidic nature, contains protein and minerals, and has been stabilized in dispersion without showing any protein aggregation or the like even in the absence of a stabilizer. It is also intended to provide such an acidic protein food or drink which shows no protein aggregation even in the case of using not only minerals hardly soluble in aqueous media but also highly soluble minerals. By using an acid-soluble soybean protein, it is possible to provide an acidic mineral-containing food or drink which has a high stability without resort to a stabilizer as an essential component. Owing to the acidic nature, moreover, a product having a refreshing flavor, which is never achieved by neutral foods or drinks, can be prepared.

Abstract: The problem to be solved by the invention is to provide a food or a drink containing an acidic protein which has a favorable flavor with relieved astringency characteristic to a protein dissolved under acidic conditions to thereby broaden the flavor variety of protein-containing foods or drinks. The above problem can be solved by adding a water soluble polysaccharide, a water soluble basic salt, an alkali metal salt of an organic acid, a basic monosaccharide, a basic oligosaccharide or the like to a food or a drink containing a protein dissolved under acidic conditions to thereby relieve the astringency originating in the protein dissolved under acidic conditions.

Abstract: The present invention is intended to provide acidic gel foods containing soybean protein to diversify means of taking soybean protein in daily eating habits. Using the acid-soluble soybean protein as specified in the description, an aqueous solution or an alcohol-containing aqueous solution of the protein is adjusted to pH 3 to 4.5. Then an acid having 2 or more acid groups per molecule or its salt or a salt of another acid is added thereto and the mixture is heated to form a gel. Thus, acidic gel foods including a jelly-like food favorable as a food can be obtained.

Abstract: It is intended to provide a soybean protein material which is excellent in solubility, stability, emulsifying properties and gel-forming properties under acidic conditions and thus advantageously usable in acidic foods, its production process, and acidic foods using the soybean protein material. A solution containing soybean protein is subjected to a treatment for eliminating or inactivating polyanionic substances contained therein and/or adding a polycationic substance and then heated at above 100° C. under acidic conditions. Thus, a soybean protein having a high solubility under acidic conditions and thus being appropriately usable in acidic foods can be obtained. By using this protein, protein foods in an acidic region can be provided. Further, by combining the above-described treatment with a protease-digestion treatment, a soybean protein hydrolysate having a high solubility in an acidic region can be efficiently obtained.