Antioxidant Compounds for the Inhibition of Enzymatic Browning by Polyphenol Oxidases in the Fruiting Body Extract of the Edible Mushroom Hericium erinaceus

Abstract

Mushrooms are attractive resources for novel enzymes and bioactive compounds. Nevertheless, mushrooms spontaneously form brown pigments during food processing as well as extraction procedures for functional compounds. In this study, the dark browning pigment in the extract derived from the edible mushroom Hericium erinaceus was determined to be caused by the oxidation of endogenous polyphenol compounds by the polyphenol oxidase (PPO) enzyme family. These oxidized pigment compounds were measured quantitatively using a fluorospectrophotometer and, through chelation deactivation and heat inactivation, were confirmed to be enzymatic browning products of reactions by a metalloprotein tyrosinase in the PPO family. Furthermore, a transcript analysis of the identified putative PPO-coding genes in the different growth phases showed that tyrosinase and laccase isoenzymes were highly expressed in the mushroom fruiting body, and these could be potential PPOs involved in the enzymatic browning reaction. A metabolite profiling analysis of two different growth phases also revealed a number of potential enzymatic browning substances that were grouped into amino acids and their derivatives, phenolic compounds, and purine and pyrimidine nucleobases. In addition, these analyses also demonstrated that the mushroom contained a relatively high amount of natural antioxidant compounds that can effectively decrease the browning reaction via PPO-inhibitory mechanisms that inhibit tyrosinase and scavenge free radicals in the fruiting body. Altogether, these results contribute to an understanding of the metabolites and PPO enzymes responsible for the enzymatic browning reaction of H. erinaceus.

Effect of domestic cooking methods on total phenolic content, antioxidant activity and sensory characteristics of Hericium erinaceus

“…HE was found to contain a considerable amount of reducing sugar (Heleno et al . 2015), amino acid (Kim, 2020), as well as purine and pyrimidine nucleobases (Kim, 2020) that could potentially participate in the Maillard reaction in order to generate novel compounds with antioxidative potency and characteristic flavour profiles.…”

Mushroom Nutrition as Preventative Healthcare in Sub-Saharan Africa

“…The Hericium fruiting body contains polyphenol oxidases (PPOs), including tyrosinase and laccase, which are strong antioxidant substances [74]. Forest dweller Hericium erinaceus strains were first reported in temperate forests of North Africa and Ghana and known to have anti-peptic ulcer activity [44,[75][76][77].…”

Assessment of toxic effect ofCentella asiaticaextract and its application as natural preservative in fresh‐cut mango, pear and cabbage

“…Natural antioxidants play a crucial role in the self-defense mechanism of fruiting bodies in plants to scavenge the free radicals to inhibit browning (Kim, 2020;Sommano et al, 2019).…”

“…Enzymatic browning is derived from the oxidation of endogenous polyphenol compounds which result browning in food (Kim, 2020). It is a common sign that appears in the quality degradation of FCFV due to the enzymatic activity of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL), often oxidized with phenolic compounds to induce color change (He et al, 2020;Ioannou & Ghoul, 2013;Vivek et al, 2019).…”