Biochemical changes associated with mushroom browning in Agaricus bisporus (Lange) Imbach and Pleurotus florida (Block &Tsao): commercial implications

Rajarathnam, S. and Shashirekha, M. N. and Rashmi, Sudhir (2003) Biochemical changes associated with mushroom browning in Agaricus bisporus (Lange) Imbach and Pleurotus florida (Block &Tsao): commercial implications. Journal of the Science of Food and Agriculture (83). pp. 1531-1537.

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Abstract

Biochemical changes associated with mushroom browning in Agaricus bisporus and Pleurotus florida were studied. With increasing storage temperature from 0 to 25 ◦C there was an increase in phenol oxidase activity up to 15 ◦C followed by a decrease at 25 ◦C in both mushrooms. Loss of water content in fresh mushrooms had a direct relationship with phenol oxidase activity, which could be correlated with the visual degree of mushroom browning. A bisporus displayed higher phenol oxidase activity, about two to three times that of P florida. The phenol oxidase activity in both mushroom varieties was studied on a range of phenolic compounds with diverse functional groups. A bisporus exhibited intense reactions to tyrosine and catechol, while P florida did so to guaiacol and catechol. The two mushrooms differed in the degree of their oxidation reactions relative to the functional groups. In A bisporus the skin had more phenolics than the flesh; P florida contained fewer phenolics, while the stalks of both mushrooms had low phenolics contents. FTIR spectral studies of intact mushrooms during browning showed a characteristic decrease in phenolic hydroxyls; first-derivative spectra were used to assess relative peak intensities. Of the chemicals tested for their effect on phenol oxidase activity, 0.1M sodium carbonate favoured the immediate development of an orange chromogen in P florida, while mild alkaline solutions favoured the enzyme activity, and acidic solutions at the 0.1M level completely inhibited the browning reaction in both mushrooms.

Item Type:	Article
Uncontrolled Keywords:	Agaricus bisporus; browning; FTIR spectra; mushroom; phenol oxidase; phenolic oxidation; Pleurotus florida
Subjects:	600 Technology > 08 Food technology > 29 Microbiological food > 03 Mushroom 500 Natural Sciences and Mathematics > 07 Life Sciences > 03 Biochemistry & Molecular Biology > 04 Biosynthesis
Divisions:	Fruit and Vegetable Technology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	26 Jun 2008 04:49
Last Modified:	01 Jul 2015 11:42
URI:	http://ir.cftri.res.in/id/eprint/1764

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