EFFECT OF PRETREATMENTS AND STORAGE ON THE AMINO ACID CONTENT OF CANNED MUSHROOMS

The aim of the present work was to determine the effects of pretreatment, canning and 12-month storage on the amino acid content in Agaricus bisporus and Boletus edulis mushrooms. The pretreatment prior to canning involved blanching or soaking and blanching mushrooms in water or in solutions containing sodium metabisulphite, citric acid, L-ascorbic acid and/or low-methylated pectin. After storage of canned mushrooms, significant decreases in alanine, asparagine and, in most cases, glutamine and methionine (A. bisporus), and in alanine, cysteine, proline, methionine and valine (B. edulis) were observed. Blanched A. bisporus products had significantly higher levels of alanine, asparagine, glutamine, histidine, serine, tyrosine, methionine and threonine than blanched and soaked, and in the case of B. edulis, higher of arginine, asparagine and glycine. Compared with the reference protein pattern FAO/WHO for adults, there were no limiting amino acids in either fresh or canned mushrooms. PRACTICAL APPLICATION Edible mushrooms and preserved mushroom products are generally considered to be low in nutritional value. The Practical Application of the work was intended to address this widely held view with respect to the amino acid content and protein quality in fresh and preserved Agaricus bisporus and Boletus edulis mushrooms, that is, in some of the most commonly consumed preserved mushrooms. With respect to the FAO/WHO protein patterns, there were no limiting amino acids in this material. It was also shown that from a practical point of view, the type of pretreatment applied had little effect on amino acid content or protein quality. Although the canning process and storage of canned products caused decreases in the levels of individual amino acids, protein quality in these products was not very much lower than in fresh mushrooms.