UPLC-UV Method for the Quantification of Free Amino Acids, Bioactive Amines, and Ammonia in Fresh, Cooked, and Canned Mushrooms

Abstract

Mushrooms are valued due to health-promoting properties and small environmental footprint. The simultaneous determination of free amino acids (17), amines (10), and ammonia in fresh, cooked, and canned Agaricus bisporus was investigated. An AQC-derivatization method was developed and validated. Norvaline was an adequate internal standard. The method was green, fast, and fit for the purpose (quantification limits, 0.14–1.92 mg/100 g; recoveries, 80–110%; repeatability, < 10%; reproducibility, < 15%). Fifteen amino acids were detected in fresh mushroom: alanine and glutamic acid were prevalent (~ 20%) followed by proline. Spermidine was the only amine detected (6.4–8.5 mg/100 g). Ammonia was present at low levels (2.8–5.5 mg/100 g). High amounts of these amino acids and spermidine warrant important health-promoting properties. The levels of amino acids, amines, and ammonia varied among lots from the same source, suggesting the influence of production conditions. During thermal processing, changes were observed: cooking affected the least (losses mainly of glutamic acid, arginine, glycine, serine, threonine, proline, and alanine, ~ 50%). Spermidine and ammonia were not affected. During canning, the losses were higher (~ 70%) for glutamic acid, serine, valine, proline, arginine, glycine, and aspartic acid. There were losses of ammonia (39%) and spermidine (24%). A two principal component model explained 97.8% of the variance and it was able to separate fresh from processed mushroom. Hierarchical cluster analysis confirmed the potential of using amines and amino acids to separate fresh from processed mushroom.