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From BIOL 2P96 Jan 2013 Group 02

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Fungi as food sources (non-fermentation).

Mycophagy Throughout History

A Roman floor mosaic depicting picked edible mushrooms in a decorative bowl

Ancient Times

Fungi has been used as a food source by humans for millenia. Archaeological records show edible mushroom fossils along with humans who lived approximately 13000 years ago in what is now modern day Chile ^[1]. A more thorough record of mushrooms as a food source can be dated back to texts written during the Han Dynasty in ancient China (206 BCE-220 CE). In ancient societies around the globe, the mushroom was not only prized for its medicinal properties, but it was also believed to have magical properties associated with immortality.

Emperor Wu of the Han dynasty went so far as to call for large expeditions to attempt to find these elusive mythological Fungi ^[2]. Fungi shared this mythical status in ancient Egypt. Hieroglyphic depictions of fungi dating back to 4500 BCE can be seen throughout Egypt. They can even be found in the Book of the Dead where they are described as being the "food of the Gods" ^[3]. The Pharaohs explicitly outlawed the consumption of fungi among the common populous as they were seen as only fit for royal consumption ^[4].

Antiquity

In Ancient Greek and Roman times, the mushroom was also a highly prized and was mainly consumed by the upper class. A particular favourite of the Emperors of Rome was the Amanite caesarea or Caesar's Mushroom, regularly on the menu at grand feasts. Unfortunately, its strong resemblance to poisonous varieties made it a relatively common and effective means of assassination. The poison's symptoms would manifest the following day and the victim would die in a week's time ^[5].

Mesoamerica

Of the few Mayan texts which survived the coming of the Spanish Conquistadors, there are hieroglyphics depicting what appears to be a man outstretching an offering of a mushroom to some sort of Deity. This suggests that mushrooms were integral to religious ceremony amongst the ancient Mayan peoples ^[6].

Mayan deities holding mushrooms

Beginnings of Commercialization

Fungi was first intentionally grown as a crop around 600 CE. In the seventeenth century, mushrooms were first cultivated by the addition of spore laden manure into fresh piles of manure. In 1886 the first sterile techniques were used in order to ensure that only the fungi in question would grow on the substrate. In 1905, it was first discovered that one could produce fungi directly from tissues and not from spores themselves. These discoveries along with the prospects of indoor mushroom production paved the way for the manufacturing techniques used today for mass production ^[7].

“Chicken-of-the-Woods”

(a.k.a Laetiporus conifericola, Laetiporus sulphurous, sulphur shelf)

The texture of cooked pieces is similar to that of chicken, thus the name. ^[8]

Morphology

Chicken-of-the-wood is a widespread and common fungus. It is rich yellow to orange in colour, which fades over time. It is commonly referred to as bracket-fungi due to its shape and shelf-like growth. Fruiting bodies can form up to 30 cm across. They are described to have a smooth, but uneven surface, with a tough, leathery texture.^[9] The underside of the fungi has a stippled appearance because it is lined with a series of tubes where its spores (3-5 per mm) are released. ^[10]

Habitat

‘Chicken-of-the-woods’ is commonly found fruiting on living trees, logs or stumps. They are commonly found of conifers and hardwoods across North America. ^[11]

Edibility

Edible margins, found to cause gasrointestinal upsets in some individuals. ^[12] Finding and cooking 'chicken-of-the-woods'

Amanita virosa “Destroying Angle”

Amanita virosa is commonly referred to as Destroying Angel belongs to the Phylum Eumycophyta, Class Basidiomycetes, Order Agaricales and Family Amanitaceae. The name ‘amanita’ is derived from the Greek meaning ‘a kind of fungus’, and ‘virosa’ is derived from the Latin ‘virosus’ meaning a ‘fetid’ or ‘poisonous’. ^[13]

The name Destroying Angel is referred to the fact that A. virosa is pure white like an angel’s veil but it is poisonous. ^[13] Destroying Angle is white, shinny and has convex cap; Destroying Angle is sticky when it’s wet. Underneath the cap there is lots of that is pure white. Also the stipe is rough but has delicate cotton-like shaggy tufts. ^[13]

Its cap is a bell-shaped and slimy surface. It has a very strong unpleasant odour. As Destroying Angle matures, it becomes drier with a silky sheen, still white but becomes more tinged with yellow or brown colour in the center of its cap. A. virosa spores are white and about 8-19 mm in diameters with a length-to-width being less than 1.25mm. ^[13]

Habitat

Destroying Angel is often found in hardwood, mixed or/and leafy woods. It is found in principally in coniferous forests and in hardwood forests. It is also found on poor soil and its characteristic occurrence is sporadic and solitary. Destroying Angle appears in midsummer to autumn and is less common in cold season. ^[13]

Poisons

The toxic peptide found in ‘’A. virosa’’ is the Virotoxins. Virotoxins are monocyclic heptapeptides, which contains D-serine instead of L-cysteine. ^[13] Virotoxins has six toxic elements which are: Viroidin, Viroisin, Deoxoviroisin, Ala-viroidin, Ala-desoxoviroidin and Deoxoviroidin. Also another toxin found in A. virosa is Amaninamide. ^[13] These toxins are very complex polypeptides molecules, which are composed of amino acids. These amino acids cause the breakdown of liver cells. ^[13]