Flavour quality

A complete understanding of the flavour chemistry and biochemistry of volatile components of fruits and vegetables is important in order to improve the flavour quality of fresh and processed produce that complies with the consumer needs for better quality vegetable and fruit products. 

A wide range of volatile compounds from Indian mango were identified by pioneer group research [20,21]. Esters, lactones, monoterpenes, sesquiterpenes, and furanones were among the volatiles. It has been suggested that the ratio of palmitic to palmitoleic acids determines the flavour quality of the ripe fruit, a ratio of less than 1 resulting in strong aroma and flavour [44]. 

Compound Flavour quality Threshold (mgL water) Threshold (mgT ethanol solution) Typical concentration [mgL (40% v/v)] ... 

Table 10.2 presents a summary of odour qualities, odour thresholds in water, and concentrations of some selected volatile compounds, which are characteristic flavour impact compounds, owing to their typical flavour quality and their rather low odour thresholds. These compounds are not formed during fermentation but originate from the raw material and contribute significantly to the typical flavour of a fruit. The components summarised in Table 10.2 are important compounds in wine and different fruits and are discussed later. 

While in ancient times, the sensorial properties of a flavour for foodstuffs were of major importance, modern flavours have to perform like multifunctional systems. Physical form, chemical and mechanical stability and controlled release mechanisms are meanwhile essential criteria for the flavour quality. All these properties have to be addressed by a flavourist in close cooperation with technologists. Therefore, knowledge about food product properties must lead to a careful and intelligent evaluation of the flavour system as an important driver for the success of the final product. 

When the final juice product is a concentrate, the clear filtered or cleaned cloudy juices are automatically subjected to heat treatment during the course of their concentration. (Figure 3.7 provides on overview of the concentration process.) Heat treatment of juices is an area where the design of process requires careful consideration in order to avoid any detrimental effects on flavour and appearance of the product. Early evaporators had demonstrated that high-vacuum-low-temperature processing produced concentrate of good flavour quality, but it was soon discovered that there was a drawback in that the heat treatment was insufficient to deactivate pectin methylesterase, which gave rise... 

Studies on the qualitative and quantitative changes in the flavour of juices from Monarch and Bergers weiBe Kugel varieties showed the presence of 3-butylphthalide enantiomers. The enantiomeric distribution of 3-butylphthalide lowers the flavour quality of the Bergers weiBe Kugel celery... 

The production of quality fruit requires between 1600 and 1800 hours of sunshine per annum. Sunny years have a beneficial effect on both the external and the internal quality of the fruit (firm peel, firm flesh, high sugar content and good flavour quality). 

RUBiNOEA (v). Origin Czech Republic, Prima X Rubin cross Vj-resistant striped red colour, good flavour quality low yield and small fruit size vigorous shoot growth with strong tendency to defoliation, difficult to train. 

ENTERPRISE (v). Origin USA, Selection No. Coop 32 multiple cross of Malus floribunda 821, Golden Delicious and McIntosh Vj-resistant, some susceptibility to canker dark-red colour and moderate flavour quality, high fertility and large fruit size moderate shoot growth, sensitive to cold in storage. 

RESi (v). Derived from Clivia ripening end of September, yield medium to high, early-bearing fruit small to medium size, three-quarter red colour (mottled to striped), flavour quality medium growth weak to semi-vigorous Vj scab resistant, little mildew storage life in cold storage until March. 

The examples discussed above clearly demonstrate that C02-extraction is a more gentle procedure than steam distillation. The smaller processing stress widely avoids the formation of artefacts. Therefore C02-extracts often have a better efficacy or a richer aroma profile reflecting the complete flavour or fragrance spectrum of the herbal raw material. This is also confirmed in the literature where professional fla-vourists have compared the aroma profiles of C02-extracts, essential oils and oleores-ins for a range of different spices [7]. Moreover C02-extraction is carried out under precisely standardised and controlled conditions which allow reproducible results. Since C02-extracts have their own character different from the usual distillates, they are new and powerful means for flavourists and food technologists to modify, improve or boost existing products or to create new premium flavour qualities. 

Additional remark The sensory qualities of extracts produced with ethanol or acetone (oleoresins) exceed those of the essential oil, as apparently some high-boiling constituents are important for the flavour quality [42[. 

The flavour profile of a composition can be calculated or described as a linear combination of the vectors of the individual components using the flavour quality as the direction of the vector and the intensity as its length. Components with a similar quality harmonize well and strengthen each other. Components with different quality add a new dimension to the flavouring a trace of lemon oil in a vanilla flavouring turns it into a fresh cake flavouring. 

Dealing with flavourings, quality changes in finished products and instability problems with flavourings are often encountered. From our experience we know, that 100% stability is not attainable ... 

O Rourke, T. (December 2000). Flavour quality. Brewer s Guardian. 29-31. 

Powers, J.L Keith, E.S. Stepwise discriminant analysis of gas chromatographic data as an aid in classifying the flavour quality of foods. JFood Sci. 1968, 33 207. 

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