Natural food and beverage flavour enhancers - Natural Food Additives, Ingredients and Flavourings - page 92

2010). The authors went on to react GMP with sugars and amino acids in order to
isolate and identify a further 14 Maillard-modifi ed guanosine 5′-monophosphates
(Festring and Hofmann 2011). Sensory analysis found the RUC of these
compounds, compared to IMP, varied from 0.08 to 7, whereas the RUC for GMP
alone was 2.4. The highest RUC (7.0) was for the trisodium salt of the S enantiomer
of N 2 -(1-carboxyethyl)guanosine 5′-monophosphate.

4.5 Interactions in the perception of non-volatile tastants and
volatile or semi-volatile fl avour compounds
Taste-aroma interactions are now widely reported as a potential route to reduce the
level of tastants (salt or sugar) in foods. Recently, Batenburg et al. (2010)
demonstrated that several savoury aroma compounds had the capacity to enhance
salt taste perception, the main consideration being that the aroma type needed
to be congruent with a salty taste (for example, compounds having 'brothy',
'meaty' and 'roasted notes'). The volatile with the greatest impact was sotolon
(4,5-dimethyl-3-hydroxy-2(5 H )-furanone). Within a bouillon, a 30% sodium
reduction was achieved through the use of a potassium chloride salt replacer with
added sotolon.
Celery is a widely used fl avour enhancer in general culinary use. A recent
investigation separated volatile and non-volatile fractions of celery in order
to determine which had the greater effect on fl avour enhancement (Kurobayashi
et al. 2008). The volatile fraction was found to be responsible and three phthalides
(sedanenolide, 3- n -butylphthalide and sedanolide) were found to enhance both
umami and sweet taste perception in a chicken broth.
Volatile aroma compounds can also enhance sweetness. In 1968 a patent was
fi led on the use of maltol (2-methyl-3-hydroxy-pyran-4-one) as both a fl avour and
sweet taste enhancer. According to Bouchard et al. (1968), 15% of sugar in food
could be substituted with 5-75 ppm maltol. Similar volatile compounds such as
4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2 H )-furanone, 2-hydroxy-3-methyl-2-
cyclopenten-1-one and 3-hydroxy-4,5-dimethyl-2(5 H )-furanone have also been
found to enhance sweet perception (Namiki and Nakamura, 1992). One problem
with using such volatile compounds in enhancing sweet taste is that their own
characteristic caramel-like aromas may be inappropriate for the food products
targeted for enhancement.
Controlling aroma release can also have an effect on perceived sweet taste
intensity. In a recent study, sucrose and a volatile ester, iso -amyl acetate, were
either delivered to participants continuously or by pulsing in or out of phase.
Sweetness intensity was increased where the tastant and volatile were delivered
out of phase (Burseg et al. 2010).
In addition to volatile fl avour compounds enhancing sweet taste, a reversal of
these roles is also often seen. In a study where green, orange or strawberry fl avours
were applied to beverages, the fl avour perception increased as the sweetness

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