Phenolic flavours

Firmenich R., G., R-E. and F-H. (Firmenich Cie) (1969q) Phenolic flavouring agents. Br Patent 1156488. 

Off-flavours may arise from the activities of all the wild yeasts encountered. Pichia and Candida species will oxidize ethanol in a vessel exposed to air to produce acetic acid, while Saccharomyces diastaticus will attack malto-tetraose and often dextrins to produce ethanol. There are also differences between culture yeast and wild yeast with respect to the production of esters, fusel alcohols, organo-sulphur compounds, hydrogen sulphide, vicinal diketones and other products important in beer flavour. Phenolic flavours are known to be produced by certain wild yeasts. [95]. 

Vanbeneden, N., Gils, R, Delvaux, R, Delvaux, R R. (2008). Formation of 4-vinyl and 4-ethyl derivatives from hydroxycinnamic acids occurrence of volatile phenolic flavour compounds in beer and distribution of padl-activity among brewing yeasts. Food Chemistry, 107, 221-230. http //dx.doi.Org/10.1016/j.foodchem.2007.08.008. 

Vanbeneden N, Delvaux F, Delvaux FR (2006) Release of phenolic flavour precursors during mashing. In Proceedings of Xllth De Clerck Chair, Leuven... 

Vanbeneden, N., Saison, D., Delvaux, F. and Delvaux, F. 2008. Release of phenolic flavour precursors during wort production Influence of process parameters and grist composition on ferulic acid release during brewing. Food Chem. Ill 83-91. 

A huge variety of biologically active phenolic compounds containing one or more aromatic rings are found naturally in plant foods, where they provide much of the flavour, colour and texture. The simpler phenolic substances include ... 

EtOH extraction was the most efficient way to improve the flavour of the phloem. A solvent/solid ratio of at least 10 1/kg was needed to achieve a significant change in the taste. The loss of catechins was approximately 27% and that of lignans was 35%. All the catechins and lignans were found from the EtOH extract. Losses of lignans and catechins were smaller with other sovents, but either the taste was not modified or the cost of solvent treatment would be too high. Phenolic compounds like lignans and catechins also have a bitter taste and some improvement in flavour may have occurred because of the lower concentration of these. The disappearance of the characteristic... 

Another illustration of the enormous potential of catalytic methodologies in fine chemicals manufacture is the new Rhone-Poulenc process for the flavour ingredient, vanillin (Ratton, 1998). The process involves four steps, all performed with a heterogeneous catalyst, starting from phenol (Fig. 2.37). 

Vanillin (4-hydroxy-3-methoxybenzaldehyde) in ethanolic solution - as supplied as a flavouring agent - was dimerized by sunlight or more rapidly under a mercury lamp to dehydrodivanillin (3). This is a typical ortho-phenol coupling reaction [20],... 

Partial least squares regression analysis (PLS) has been used to predict intensity of sweet odour in volatile phenols. This is a relatively new multivariate technique, which has been of particular use in the study of quantitative structure-activity relationships. In recent pharmacological and toxicological studies, PLS has been used to predict activity of molecular structures from a set of physico-chemical molecular descriptors. These techniques will aid understanding of natural flavours and the development of synthetic ones. 

Fig. 7.5 Some phenols and related compounds that are important for the flavour of fruits and...

Vanilla flavour is not only determined and characterised by the vanillin molecule, but also by many more phenolic compounds and vanillin derivatives. Two examples of molecules that recently obtained FEMA-GRAS status are vanillyl ethyl ether and vanillin 2,3-butanediol acetal (Scheme 13.11). Vanillin can be hydrogenated to form vanillyl alcohol, which is also used in vanilla flavours. Vanillyl alcohol can be reacted with ethanol to form vanillyl ethyl ether. Vanillin can also form an acetal with 2,3-butanediol (obtained by fermentation of sugars) catalysed byp-toluene sulfonic acid in toluene. 

Reduction of the sodium chloride level can result in taste problems and flavour shifts. There are several approaches to maintain salt taste. Most often, potassium chloride is used, because it shows the most prominent salty taste of those applicable inorganic salts. Lithium chloride is the most salty salt but cannot be used for toxicological reasons. Most consumers, however, complain about the bitter, chalky taste of KCl-containing formulations. Development of sodium-reduced products using mineral salts is a challenge and the whole product formula has often to be adapted [25]. Therefore, the main focus of the research was the search for masking compounds or technologies to cover the bad taste of KCl, e.g. phenolic acids and derivatives [26] and lactisol [27]. 

Conjugates of flavour compounds were also found in milk phenols can be liberated by /i-glucuronidase, arylsulfatase and acid phosphatase from their respective precursors [57]. 

The palatability of safflower meal to poultry tends to be low (Ravindran and Blair, 1992) due to the presence of two phenolic glucosides matairesinol-p-glucoside, which imparts a bitter flavour, and 2-hydroxyarctiin-p-glucoside, which also has a bitter flavour and has cathartic properties (Darroch, 1990). Both glucosides are associated with the protein fraction of the meal, and they can be removed by extraction with water or methanol, or by the addition of P-glucosidase. 

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