In vitro digestion of spermidine and amino acids in fresh and processed Agaricus bisporus mushroom.

Mushrooms are significant sources of amino acids and bioactive amines; however, their bioaccessibility can be affected by processing and during in vitro digestion. Fresh Agaricus bisporus mushroom was submitted to cooking and canning and samples were submitted to in vitro gastric and gastric-intestinal digestions. An UHPLC method was used for the simultaneous determination of 18 free amino acids, 10 biogenic amines and ammonia in the samples. Fresh mushroom contained 14 free amino acids, with predominance of alanine and glutamic acid; spermidine was the only amine detected; and ammonia was also detected. Spermidine levels were not affected by cooking, but there was a significant loss (14%) after canning. Spermidine levels were not affected by the in vitro gastric and intestinal digestion, suggesting full bioaccessibility. There was a significant decrease on total amino acids levels after cooking and canning, with higher losses for aspartic and glutamic acids in cooked and for aspartic acid and valine in canned mushrooms. After the in vitro gastric and intestinal digestions, the total levels of amino acids increased and two additional amino acids (arginine and methionine) were detected. During in vitro digestion many of the amino acids were released mainly in the intestinal phase. After in vitro digestion, amino acids per gram of protein of mushrooms are adequate for most FAO amino acid pattern for adults. Multivariate analysis confirmed that protein hydrolysis in processed mushrooms is higher in intestinal phase. Bioaccessibility data for spermidine in A. bisporus is a novelty and increase the value of this food.