Natural food and beverage flavour enhancers - Natural Food Additives, Ingredients and Flavourings - page 88

Mushrooms
Dried mushrooms are traditionally used throughout Asia for fl avour enhancement.
As well as the dried shiitake mushrooms ( Lentinula edodes ) used in dashi, there
are many dried mushrooms used in Taiwanese cooking too (Table 4.1). In Europe,
dried Porcini mushrooms are commonly used. As well as high levels of glutamic
acid, dried mushrooms usually contain the most potent umami 5′-nucleotide,
GMP. Ninomiya (1998) stated that it was only Shiitake mushrooms that contained
GMP, but this is not supported by other researchers who have found high GMP
in dried Agaricus, Agrocybe, Boletus, Flammulina and Pleurotus species (Yang
et al. 2001; Tsai et al. 2007).
Harvesting mushrooms at different stages of maturation affects the level of
amino acids and ribonucleotides in the dried mushroom, although the effects are
not consistent over all compounds. In Agaricus bisporus , the total levels of free
amino acids and 5′-nucleotides increased initially with maturation and then
decreased; however glutamic acid increased throughout maturation (from 728 to
1059 mg/100 g dry weight) and GMP increased from 8 to 14 mg/100 g (dry
weight) before reaching a plateau (Tsai et al. 2007).
To use dried mushrooms as a fl avour enhancer, the mushrooms are typically
soaked in water; the aqueous extract can then be used as a basis of a culinary
stock. The level of umami compounds extracted by water is not generally as high
as the total level in the mushrooms, for example for amino acid analysis the
mushrooms are normally extracted with hydrochloric acid (Yang et al. 2001; Tsai
et al. 2007). In the experience of the author, the level of grinding of the dried
mushrooms and the effi ciency of shaking during extraction are important to obtain
an optimal extract of umami compounds from dried shiitake mushrooms.

Mycoprotein by-product (Mycoscent®)
A recent natural fl avour enhancer that has been marketed in the UK is a product
branded Mycoscent®. This product is a by-product of mycoprotein, a vegetarian
protein product (branded as Quorn™). The mycoprotein is grown in fermenters
from the fungus Fusarium venenatum . As amino acids are water-soluble they are
extracted in washing water during the processing of mycoprotein; this is then
concentrated to form the Mycoscent™ product. This product contains over
200 mg/100 g glutamic acid and amounts of nucleotides in similar proportions to
some of the dried mushrooms (Table 4.1). At the time of writing, this product was
diffi cult to commercially acquire.

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4.3 Umami taste modifi ers and taste enhancing peptides
4.3.1 Organic acids
Some organic acids, notably succinic and tartaric acid, have been found to have
fl avour enhancement effects. Succinic acid was found to impart an umami taste in
cheese as noted above (Drake et al. 2007). It has also been found in an umami
taste fraction extracted from dried Morel mushrooms, Morchella deliciosa