Aroma formation

Carotenoids are present at low levels in tea leaf.60 Neoxanthin, violaxanthin, lutein, and B-carotene are the major components of this group. They enter into reactions that lead to aroma formation.61... 

Herrman, G., Baltes, W., Model studies on aroma formation in coffee, Coll. Sci. Int. Cafe, 9, 77, 1980. (CA96 141420f)... 

Baggenstoss J, Poisson L, Kaegi R, Perren R and Escher F. 2008. Coffee roasting and aroma formation application of different time-temperature conditions. J Agric Food Chem 56(14) 5836-5846. 

The most important steps of thermal aroma formation via the Mai Hard reaction are ... 

The first two sections of this book provide the reader with a background on the thermal generation of aromas. Included in these sections are perspectives on the regulatory aspects and the analytical methodologies at the forefront of aroma research. Subsequent sections present original research on aromas derived from various food sources. In addition, we have included a section on mechanistic studies to provide insights into aroma formation through thermal decomposition of lipid, carbohydrate, and amino acid precursors. The final section is entirely... 

Jousse et al.130 have surveyed the data available on the kinetics of aroma formation by the Maillard reaction and have assembled a simplified, but broadly based, kinetic scheme, as outlined in Scheme 3.3. 

Of the different types of lipids in foods, the phospholipids, being more unsaturated, are particularly important in relation to aroma formation in meat.151 The aroma of cooked meat was not affected by the prior extraction of triglycerides with hexane, but the use of a more polar solvent (chloroform-methanol), which extracts all lipids, including phospholipids, resulted, after cooking, in the replacement of the meaty aroma by a roast or biscuit-like one. This was reflected in the volatiles, the dominant aliphatic aldehydes and alcohols being replaced by alkylpyrazines. This implies that the participation of the lipids in the Maillard reactions inhibited the formation of heterocyclic compounds. 

K. Eichner, R. Schnee, and M. Heinzler, Indicator compounds and precursors for cocoa aroma formation, in Thermally Generated Flavors Maillard, Microwave, and Extrusion Processes, T. H. Parliment, M. J. Morello, R. J. McGorrin (eds), Vol. 543, American Chemical Society Washington, DC, 1994, ACS Symposium Series, 218-227. 

W. Baltes and G. Bochmann, Model reactions on roast aroma formation. IV. Mass spec-trometric identification of pyrazines from the reaction of serine and threonine with... 

Stabilizing reactions that affect wine colour and clarity, structural changes in the phenolics and new aroma formation all take place during oak wood aging. None of these reactions occurs in tanks or bottles, which are inert, do not interact with the wine, and do not allow the controlled oxidation that takes place in oak barrels. 

It Is generally recognised that In fruit and vegetable production more attention should be given to the hidden sensory quality parameters, such as flavor and texture. These quality attributes are the result of a number of pre- and post-harvest factors and are closely related with fruit ripening. Palllard distinguishes external and Internal factors Influencing aroma formation In fruits (U. The... 

Flavor formation in fruit products has also extensively been reviewed (10), A distinction can be made between the primary aroma components, which are biosynthesized by the whole fruit and secondary aroma compounds (e.g. hexanal, 2-hexenal), formed after disruption of the cells during processing or chewing (11). The Importance of the peel for aroma formation has also been stressed by several authors (12). An extensive literature on the respiration climacteric (13), the role of ethylene (14) and the enzymes and substrates required for biosynthesis is available (15). 

One of the first researchers to study the aroma formation during the Maillard reaction was Ruckdeschel [21] in 1914. He described the reaction product of glucose with phenylalanine as rose-like, with leucine as bread-like, with valine as fine roasted and with alanine as similar to coloured malt. 

Thiamine degradation has a good share in meat aroma formation [17,64]. Neutral and acidic conditions favour the formation of 13 [65], which is a key component in boiled meat [66, 67[. It has already earlier been identified in a meat-like process flavouring [68[, prepared from cysteine, thiamine, hydrolysed vegetable protein and water [69]. Bolton and co-workers [70] showed that in model experiments with thiamine, [ S]-cysteine, glucose and xylose, only 8% of 13 contained sulphur from cysteine. They concluded that thiamine (43) was the primary precursor for the generation of 13 in this system. 

To correlate differences in the aromas of different samples, first, the most-odor active compounds in the samples treated without HHP have to be identified. The subsequent application of a comparative Aroma Extract Dilution Analysis (AEDA) is a very useful tool to screen and compare odor activities of the same odorants in two different samples. To gain first insights into the influence of HHP on aroma formation in Maillard type reactions, the key odorants formed at 100°C in proline/glucose mixtures treated under HHP or at normal pressure were compared. Labeling experiments were then performed to elucidate the influence of HHP on formation of transient intermediates and an pathways leading to selected key odorants. 

Successful attempts have been made for further development of brewer yeast strains, which increases the rate of fermentation, improves aroma formation... 

Ogawa, K., Moon, J.-H., Guo, W., Yagi, A., Watanabe, N., and Sakata, K. 1995. A study on tea aroma formation mechanism Alcoholic aroma precursor amounts and glycosi-dase activity in parts of the tea plant. Z. Naturforsch. C Biosci. 50 493-98. 

Lim, M.H., Velasco, P.J., Pangbom, R.M., and Whitaker, J.R. 1989. Enzymes involved in off-aroma formation in broccoli. In Quality Factors in Fruits and Vegetables (MJ. Comstock, ed.), pp. 73-82. ACS Symposium Series 405. American Chemical Society, Washington, DC. 

An examination of the quantitative data of aroma formation in the heated WGH-G or DWGH-G samples provides a rather clear trend. Even though the amnwnia released from... 

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