Sweet volatile compounds

Selecting an approach Off-flavors are typically due to volatile compounds present at extremely low levels. (Flavor is sensed more by the olfactory system than the tongue, which senses only 5 flavors, sweet, sour, bitter, salty, and umami). GC is ideal for detecting low levels of volatile components. In this case, headspace GC will allow you to treat the plastic directly. Since the off-flavor is suspected to be derived from the polypropylene packaging material, you decide to compare different samples ( good vs. bad ) of the material using headspace GC with both a flame ionization detector (FID) and a sniff port. These chromatograms are shown in Fig. 21.9. 

Cherries are divided into sweet cherries (Prunus avium) and sour cherries (Prunus cerasus). The majority of sweet cherry volatile compounds are alcohols, aldehydes, esters and acetic acid. Sweet cherry fruits contain many volatile... 

Important aroma compounds of black currant berries have been identified mainly by GC-O techniques by Latrasse et al. [119], Mikkelsen and Poll [115] and Varming et al. [7] and those of black currant nectar and juice by Iversen et al. [113]. The most important volatile compounds for black currant berry and juice aroma include esters such as 2-methylbutyl acetate, methyl butanoate, ethyl butanoate and ethyl hexanoate with fruity and sweet notes, nonanal, /I-damascenone and several monoterpenes (a-pinene, 1,8-cineole, linalool, ter-pinen-4-ol and a-terpineol) as well as aliphatic ketones (e.g. l-octen-3-one) and sulfur compounds such as 4-methoxy-2-methyl-butanethiol (Table 7.3, Figs. 7.3, 7.4, 7.6). 4-Methoxy-2-methylbutanethiol has a characteristic catty note and is very important to blackcurrant flavour [119]. 

Essences of pink and white fresh guava obtained by direct extraction of flesh juices with dichloromethane revealed that the total amount of Cs aldehydes, alcohols, and acids comprised 20 and 44% of the essence of fresh white and pink guavas, respectively [49]. The flavour of the Costa Rican guava has been described as sweet with strong fruity, woody-spicy, and floral notes [53]. One hundred and seventy-three volatile compounds were isolated by simultaneous steam distillation-solvent extraction. The terpenes and terpenic derivatives were found in this fruit in major concentrations and were strong contributors to tropical fruit notes (Fig. 8.1). The aliphatic esters contributed much to its typical flavour. 

Cutzach, I., Chatonnet, P., and Dubordieu, D. (1999). Study of the formation mechanisms of some volatile compounds during the aging of sweet fortified wines. ]. Agric. Food Chem. 47, 2837-2846. 

The colonies of this black mold are common on the walls and equipment of Tokaj cellars. C. cellare utilizes only volatile compounds which are present in the airspace of the cellar. Since it cannot tolerate ethanol contents above 2% (v / v), it never grows directly on the surface of wine, either sweet or dry. It has no direct impact on the quality of wine, although it beneficially influences the purity and humidity of the air in the cellar (Dittrich, 1977 Magyar, 2006, 2010). 

Wine is one of the most complex and interesting matrices for a number of reasons. It is composed of volatile compounds, some of them responsible for the odor, and nonvolatile compounds which cause taste sensations, such as sweetness (sugars), sourness (organic acids), bitterness (polyphenols), and saltiness (mineral substances Rapp and Mandary, 1986). With a few exceptions, those compounds need to be present in levels of 1%, or even more, to influence taste. Generally, the volatile components can be perceived in much lower concentrations, since our organs are extremely sensitive to certain aroma substances (Rapp et ah, 1986). Carbohydrates (monosaccharides, disaccharides, and polysaccharides), peptides, proteins, vitamins, and mineral substances are among the other wine constituents. 

Pyruvaldehyde is a liquid at room temperature and boils at 72°C, thus when cysteine-pyruvaldehyde mixture was heated at 80°C, the components are in solution and flavor notes reminiscent of Japanese rice cracker developed. As reaction temperatures increased gradually other flavor notes developed. In the case of cysteine-glucose system, no reaction took place until the reaction temperature reached 130°C. The flavor of cysteine-glucose was comparable to that of cysteine-pyruvaldehde at 160°C, with one exception, the glucose system had a sweet note. As temperature increased the flavor impression of both systems increased in similarity. The volatile compounds produced at 160°C in the presence of pyruvaldehyde were different from those in presence of glucose. While thiazole and thazolines were absent in the volatiles of cysteine-glucose, cysteine-pyruvaldehyde volatiles were devoid of pyridines, picolines and furans (24). 

Vegetables contain some flavor compounds, the concentrations of which are mostly too low to obtain essential oils. In the tissues of some vegetables, volatile compounds are enzymatically produced when they are disrupted. Vegetables have the function of flavoring only after their cells are disrupted or after being oil-fried. Vegetable flavors are classified in the category of savory flavor, while fruit flavors are classified as sweet flavors. 

Many microbial metabolites are volatile compounds and in terms of their sensory properties can be broken into two broad categories odorants and tastants (Table 1). Tastants include salty, sour, sweet, and bitter compounds such as amino acids, peptides, and sugars. Primary odorants typically are quite volatile and include carbonyl compounds, esters, and terpenes. There is considerable overlap between the two categories lactones, for example, have both taste and odor properties. In keeping with the theme of this symposium, volatile aroma substances will be the primary focus. 

Fig. 8.2 Lavender cultivars have only 14 volatile compounds in common out of 43 compounds detected by gas chromatography (dark bars see Fig. 8.3 for structures of each compound). Y-axis represents the natural log transformed percentage of each volatile in the floral headspace. Four cultivars are represented a) French b) Fringed c) Hidcote d) Sweet. Each bar represents a different odor. Reproduced from Kim and Lee, Journal of Chromatography A, 2002, vol. 982, pp. 31-47, with the permission of the authors and Elsevier.

Lipid oxidation is a major pathway for the formation of volatile compounds in roasted tree nuts. After the enzymes in the nuts (e.g., lipoxygenase) are inactivated by the high temperatures used for roasting, autoxidation becomes the principal source of lipid breakdown [66]. Lipid degradation reactions are not necessarily deleterious to flavor [67], and some aldehydes and ketones (e.g., n-aldehydes and 2-aIkanones) produced during roasting may impart desirable sweet, fruity, and pungent aroma notes to roasted tree nuts. 

Flavor compounds (aroma compounds). Term for volatile compounds in food that are perceived by osmoreceptors (see aroma chemicals) either directly in the nose (smelling, nasal perception) or in the pharyngeal space on eating or drinking (retronasal perception). Together with the generally non-volatile taste compounds (sour, sweet, bitter, salty, or spicy tasting compounds). F. c. make a decisive contribution to the taste of a food, the consistency of the food also contributes to the complete sensory impression. 

Recent studies of photooxidized butter and butter oil identified by aroma extract dilution analysis, 3-methylnonane-2,4-dione, a potent volatile compound derived from furanoid fatty acids (see Section C.4) (Figure 11.7). Six different furanoid fatty acids were established as dione precursors, and were found in various samples of butter made from either sweet cream (116 76 mg/ kg), or from sour cream (153-173 mg/kg), or from butter oil (395 mg/kg). Similar precursors of the dione were identified in stored boiled beef and vegetable oils. This flavor defect arising by photooxidation of butter or butter oil is apparently different from the light-activated flavor in milk,that involves the interaction of sulfur-containing proteins and riboflavin. However, more sensory comparisons are needed to distinguish between these two flavor defects due to light oxidation. 

Knudsen JT, Tollsten L, Bergstrom G (1993) Floral scents - a checklist of volatile compounds isolated by headspace techniques. Phytochemistry 33 253-280 Kobata K, Todo T, Yazawa S, Iwai K, Watanabe T (1998) Novel capseiicinoid-like substances, capsiate and dihydrocapsiate, from the fruits of a nonpungent cultivar, CH-19 Sweet, of pepper Capsicum annuum L.). J Agric Food Chem 46 1695-1697 Kobata K, Sutoh K, Todo T, Yazawa S, Iwai K, Watanabe T (1999) Nordihydrocapsiate, a new capsinoid from the fruits of a nonpungent pepper. Capsicum annuum. J Nat Prod 62 335-336... 

Budin, J.T., C. Milo, G.A. Reineccius, Perceivable odorants in fresh and heated sweet cream butters, m Food Flavors and Chemistry, Spanier, H., F. Shahidi, T.H. Parliment, C. Mussinan, C.-T. Ho, E. Contis, Eds., Royal Society of Chem., Lxtndon, 2001, p. 85. Meynier, A., D.S. Mottram, Volatile compounds in meat-related model systems Investigation on the effect of lipid compounds on the MaiUard reaction between cysteine and ribose, in Progress in Flavour Precursor Studies, P. Schreier, P. n-terhalter, Eds., Allured Publ., Carol Stream, 1993, p. 383. 

Tiu, C.S., PurceU, A.E., Collins, W. W. Contribution of some volatile compounds to sweet potato aroma. J. Agric. Food Chem. 33, 223 (1985)... 

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