Provided is an inhibitor of reactions between collagen peptides and acidic polysaccharides in foods or drinks, said inhibitor comprising a neutral or basic amino acid as an active ingredient. Also provided is an acidic jelly-like food having a pH value of 5.5 or lower, said jelly-like food comprising collagen peptides with weight-average molecular weight of 4,000-6,000 Da, acidic polysaccharide(s) and a neutral or basic amino acid. According to the present invention, reactions occurring between collagen peptides and acidic polysaccharides in foods or drinks can be effectively inhibited. Further, an acidic jelly-like food containing collagen peptides, said jelly-like food being highly transparent and having a reduced offensive smell characteristic to collagen peptides, can be provided.
