Fruity flavours

The kiwi fruit is a cultivar group of the species Actinidia deliciosa. More than 80 compounds have been identified in fresh and processed kiwi [137]. Methyl acetate, methyl butanoate, ethyl butanoate, methyl hexanoate and ( )-2-hexenal have the most prominent effect on consumer acceptability of kiwi fruit flavour [137-140]. The volatile composition of kiwi fruit is very sensitive to ripeness, maturity and storage period [138, 139]. Bartley and Schwede [140] found that ( )-2-hexenal was the major aroma compound in mature kiwi fruits, but on further ripening ethyl butanoate began to dominate. Ripe fruits had sweet and fruity flavours, which were attributed to butanoate esters, while unripe fruits had a green grassy note due to ( )-2-hexenal [140]. The most important character-impact compounds of kiwi fruits are summarised in Table 7.4. 

Twenty-nine odour-active compounds were detected by using aroma extract dilution analysis (AEDA) [60]. The results of AEDA together with GC-MS analysis showed ethyl 2-methylbutanoate (described as fruity flavour), followed by methyl 2-methylbutanoate and 3-methylbutanoate (fruity, apple-like), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (sweet, pineapple-like, caramel-like), d-decalactone (sweet, coconut-like), l-( ,Z)-3,5-undecatriene (fresh, pineapple-like), and a unknown compound (fruity, pineapple-like) as the most odour-active compounds. 

Occurring widely in nature, malic acid is closely associated with apples. It is the second major acid, after citric, found in citrus fruits and it is present in most berry fruits. Malic acid is slightly stronger than citric in perceived acidity, imparting a fuller, smoother fruity flavour. 

The same holds for products from animal cell cultures where even less results are available. With animal cell cultures especially enzymes are accessible which may be used for biotransformations of flavour precursors. Compared to the progress in the production of pharmaceutical substances from animal cell cultures it is only a question of time when processes are developed which allow the economical production of flavour chemicals not yet accessible by other routes. Quick progress is expected, among others, for sweeteners, bitter substances, essential oils, fruity flavours and vegetable flavours from cell cultures. 

Alcohols in peas are mostly formed from enzymatic oxidation of lipids. Physical damage, storage and processing of seeds could lead to the formation of alcohols (Eriksson, 1967 de Lumen et al., 1978 Oomah Liang, 2007). Volatile alcoholic compounds have distinct characteristics and they could therefore affect the taste and flavour of peas. For example, 1-propanol has an alcoholic odour and a fruity flavour 2-methyl-l-propanol has a wine odour, 3-methyl-l-butanol has a fruity, banana, sweet odour with a bittersweet taste 1-hexanol has an herbaceous, mild, sweet, green fruity odour and an aromatic flavour 1-heptanol has an aromatic and fatty odour and a spicy taste, whereas 1-octanol has a fresh, orange-rose odour and an oily, sweet taste (Burdock, 2002). 

Nowadays, more than 400 compounds forming the large-fruited strawberry Fragaria ananassa and other hybrids, Rosaceae) flavour are known, yet the importance of many of them is not yet fuhy understood. Besides a number of esters (mainly butanoates) and aldehydes, such as (Z)-hex-3-enal, which generally have green and fruity flavours, 4-hydroxy-2,5-dimethyl-2 f-furan-3-one (furaneol, also known as strawberry or pineapple furanone) and its methyl ether 4-methoxy-2,5-dimethyl-2 f-furan-3-one... 

Selection 434 (New York Muscat x Selection 362). Selection 434 is a pink-skinned, seedless selection crossed in 1977 and selected in 1984. The vine has moderate vigour, procumbent growth habit and is very winter hardy (0-8% primary bud damage in 1988-1989). Despite some inconsistency in initial observations, yields exceeded comparison cultivar Einset Seedless in a replicated trial conducted in 1993-1996. Clusters are medium sized (111 g), cylindrical, loose and approximately equal in mass to Einset Seedless. Berries are round, medium sized (2.3 g), pink skinned, moderately crisp, of fruity flavour and seedless. In some years, the hen-and-chicken syndrome will appear in which some berries do not size flower cluster thinning appears to overcome this problem. 

---