Maltol, flavouring

Flavorzyme is a commercially available proteolytic enzyme preparation by Novo Nordisk Bioindustrials. It can be used to obtain a meat-like process flavouring from defatted soybean meal. With the help of aroma extract dilution analysis, Wu and Cadwallader [61] showed in their study of 2002 the presence of key aroma compounds of roasty, meat-like aroma in the enzymatically hydrolysed and heated hydrolysed protein, e.g. maltol, furaneol, methanethiol and furanthiol derivatives. 

Several pyran-4-ones, e.g. maltol, are used as flavouring agents and 6-hydroxy-2,5,7, 8-tetramethylchroman-2-carboxylic acid is a potent synthetic antioxidant (75MI22303). 

Hydroxy-2-methylpyran-4-one (427), maltol, is an important flavouring agent and some consideration has been paid to its synthesis. A number of routes have been developed... 

Hydroxypyran-4-ones are potent flavouring materials of which maltol (427), present in roasted malt, is particularly well known. Amongst other features, it imparts a newly baked odour to bread. Kojic acid (712) is produced in an aerobic process by a range of microorganisms, notably Aspergillus oryzae, from a variety of carbohydrate sources and is used as a source of maltol. 

Chemists produce synthetic flavourings such as smoky bacon and even chocolate . Meaty flavours come from simple heterocycles such as alkyl pyrazines (present in coffee as well as roast meat) and furonol, originally found in pineapples. Compounds such as corylone and maltol give caramel and meaty flavours. Mixtures of these and other synthetic compounds can be tuned to taste like many roasted foods from fresh bread to coffee and barbecued meat. 

Flavourings that are useful for aromatising bakery and chocolate food products can be made from sulphur-free amino acids by the reaction with cyclic ketones (Fig. 3.36) such as 4-hydroxy-2,5-dimethyl-3(2//)-furanone (26), maltol (63) or 2-hydroxy-3-methyl-2-cyclopenten-l-one (64, cyclotene) [109]. Amino acids of special interest are leucine, valine, proline and hydroxyproline. The reaction is carried out favourably in fat or propylene glycol. 

The flavour of a food consists of odour, taste, and haptic and tactile sensations in the mouth ( mouthfeel ) (Fig. 3.52). This means that a flavour modifier may affect odour, taste, and/or mouthfeel of a food. Usually, only taste and/or odour are affected, although maltol and ethyl maltol have been reported to be effective in improving the mouthfeel in low-fat food systems [7]. Because of lack of a clear definition, I shall classify flavour modifiers into the five categories shown in Table 3.46. Based on this... 

It has been reported recently that maltol and ethyl maltol are also capable of improving the flavour of savoury (or spicy) foods [7]. In salad dressings, they round the spiciness and decrease the bite or acid sensation contributed by acetic acid. Both substances have also been reported to be highly effective in improving the perception of low-fat food systems [7]. Low-fat yoghurt, ice cream and salad dressings taste richer, fuller and creamier with the addition of ppm levels of maltol or ethyl maltol. In other words, their mouthfeel is improved. 

Maltol enhances the flavour of sweet foods. The addition of 5 to 75 ppm maltol may permit a 15 % sugar reduction in various sweet foods [1]. Tab. 3.51 shows some usage levels in selected foods. 

Furaneol is formed when the sugar rhamnose is heated in the presence of a substance containing an amino group through a Maillard reaction (Fig. 3.62). HMF results from heating of fructose (Fig. 3.63). Both furanones occur in various foods. For example, Furaneol has been identified in pineapple, strawberries and popcorn both Furaneol and HMF have been found in meat broth [21 [. Both furanones are applied as flavour modifiers in foods where maltol and ethyl maltol are used [1[. 

The flavouring concentrate represents the complete flavour profile in the most concentrated form and it also includes general rounding-off materials to impart a basic body for sweet taste (e.g. vanillin, maltol, 2,5-dimethyl-4-hydroxy-furan-3(2H)-one). 

Vanillin and maltol (3-hydroxy-2-methyM-pyrone) are responsible keys for the sweet, creamy flavour of chocolate. 

Heat transforms ketoacids to methylketones like 2-heptanone, 2-nonanone with a green fatty metallic blue cheese note. Hydroxyy acids form the corresponding lactones. The creamy, buttery, coconut-like 5-decanolide, 4-dodecanolide, 5-dodecano-lide contribute to the sweet creamy buttery flavour in cream and butter. Lactose undergoes a caramelisation reaction to develop sweet, caramelic maltol and 4-hy-droxy-2,5-dimethyl-furan-3(2H)-one. Lactose and milk proteins react in a Maillard reaction to roasted, nutty, burnt notes such as 2,5-dimethyl pyrazine. 

Flavour enhancers and suppressers are used in low concentrations to enhance or suppress other flavours. Examples include maltol and ethylmaltol, which have a low caramel taste and enhance the sugary feeling of products furaneol, which is used with red fruits or wild fruit flavours and vanillin, which softens bitter chocolate and fruit flavours and can also enhance the perception of sweetness. In general, sucrose suppresses bitter, sour and salty tastes, for example in chocolate, and enhances fruit flavours. A further important point for ice cream is that the perception of flavour is affected by temperature flavours are less intense at low temperatures. For this reason, ice cream and water ices are generally more strongly flavoured than products consumed at warmer temperatures, such as soft drinks (Experiment 17 in Chapter 8 demonstrates this). 

Maltol, 1% petrolatum. Flavour enhancer in fruit and chocolate flavours (Taylor et al. 1996)... 

The mutual condensation of some degradation products of sugars yields important alicychc substances called cyclopentenolones, which are characterised by a caramel flavour similar to maltol, and other secondary reaction products of sugars. For example, condensation of hydroxyacetone with lactic aldehyde yields the basic member of the homologous series 2-hydroxy-3-methylcyclopent-... 

Pyrans occurring in foods are hypothetically derived from a-pyran or y-pyran, or from a- or y-pyrones, respectively. 8-Lactones can also be considered derivatives of a-pyran. An important a-pyrone is 3-hydroxypyran-2-one, also known as 3-hydroxy-2-pyrone or 3-hydroxy-2ff-pyran-2-one, which is a 8-lactone of 2,5-dihydroxypenta-2,4-dienoic acid with a caramel-Hke flavour, which arises from ascorbic acid (see Section 5.14.6.2.2). Undoubtedly, the most important y-pyrone is 3-hydroxy-2-methylpyran-4-one, which is known as maltol (8-167), featuring a caramel (or malt) smell and taste. A large number of other y-pyrones are formed in non-enzymatic browning reactions, but as flavourings they are of Httle consequence. 

Raw or gently pasteurised milk (e.g. for 10 seconds at 73 °C) has a fine characteristic odour and sweet taste. Typical components present in low concentrations are dimethylsulfide, biacetyl, 2-methylbutan-l-ol, (Z)-hept-4-enal and ( )-non-2-enal. Milk pasteurised at higher temperatures and Ultra High Temperature (UHT) milk present the so-called cooked flavour, the appearance of which is the first measurable manifestation of the chemical changes that occur in heated milk. The substances responsible for the cooked off-flavour are sulfane and other sulfur compounds. Of particular importance are dimethylsulfide, dimethyldisulfide and dimethyltrisullide that are produced from proteins contained in the membranes of fat particles and from thiamine. Also relevant are alkane-2-ones (methylketones) generated by thermal decarboxylation of P-oxocarboxylic acids (mainly hexane-2-one, heptane-2-one and nonane-2-one), y-lactones and 5-lactones produced by dehydration of y- and 5-hydroxycarboxylic acids (mainly 8-decalactone and y- and 8-dodecalactones). Important carbonyl compounds include biacetyl, hexanal, 3-methylbutanal, (Z)-hept-4-enal and ( )-non-2-enal. In the more intensive thermal treatment of milk (sterilisation), products of the Maillard reaction play a role, such as maltol and isomaltol, 5-hydroxymethylfuran-2-carbaldehyde, 4-hydroxy-2,5-dimethyl-2 f-furan-3-one (furaneol) and 2,5-dimethylpyrazine. 

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