Abstract: A delivery envelope-type bag, which is a bag manufactured from a plastic sheet, or the like, is provided with a storage section for storing the delivery item and a flap section formed from a sealing section that seals the storage section and a peeling section located between parallel perforations, and is configured so that the flap section is folded back along a folding section and adhesively fixed to the storage section by the sealing section. In the delivery envelope-type bag: the parallel perforations and the peeling section are formed to extend to both edges; and a variety of notched sections and formed adjacent to or near the peeling section at both edges of the flap section, and/or a variety cutout sections are formed near the peeling section on the folding section side at both edges of the flap section.

Abstract: Compounds of the formula (1) ##STR1## wherein X and Y are each N or NH, Z is O or OH, (1) when X=N and Y=NH, Z=O, and *1 and *3 are double bonds, (2) when X=NH and Y=N, Z=O, and *2 and *3 are double bonds, (3) when X=N and Y=N, Z=OH, and *2 and *4 are double bonds, and R is a side chain derived from an amino acid; for example, the amino acid is glycine with R=H, alanine with R=CH.sub.3, glutamic acid with R=CH.sub.2 CH.sub.2 COOH, lysine with R=CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 NH.sub.2, or leucine with R=CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.3, and/or an analogues thereof are useful for imparting a "thick, sour" taste to foods.

Abstract: A seasoning composition containing food and an amino acid derivative that imparts a "thick, sour taste" to the food.

Abstract: A mixture selected from the group consisting of (1) gelatin and tropomyosin and/or tropomyosin peptides, (2) gelatin and paramyosin, and (3) troponin and tropomyosin and/or tropomyosin peptides, which when combined with a low-molecular weight fraction of natural extracts, and heated in water, imparts "KOKUMI" taste characteristics to food and drink.