Character impact compounds, sensory

A professional description of flavours uses as precise descriptors as possible. Chemical analytical results are combined with sensory analysis of the identified components to assess the relative importance and contribution to the flavour profile. Key ingredients or character impact compounds (CIC) are important components sine qua non to impart the typical, product characteristic, flavour, e.g. anethol for anise, eugenol for clove, 3-methyl butyl acetate for banana or ethyl butyrate to improve the juiciness of orange juice. 

Characteristic aroma components in foods and off-flavor substances in processed foods are called character impact compounds. It would be desirable to develop methods for finding such compounds with sensory methods because such information is useful in the food industry. A compilation of odor and taste threshold values was edited by Fazzalari (7). Olfactory-trigeminal response to odorants was measured using rabbits (2). However, aroma quality can be evaluated only by human sense. In spite of this fact, olfactory judgment by humans can not give constant data like... 

The chemical structures (Figure 5) of the odorants were mainly elucidated by GC-MS (Table I). Compound no 17 was identified as sotolone (Figure 6AJ. Sotolnne is likely the character impact compound of fenugreek as indicated by the high FD-faclor of 2 correspondingly low sensory threshold and characteristic aroma note... 

Over the last decades, GC-0 has been extensively used in essential oil analysis in combination with sophisticated olfactometric methods the latter were developed to collect and process GC-0 data and, hence, to estimate the sensory contribution of a single odor-active compound. The odor-active compounds of essential oils extracted from citrus fruits Citrus sp.), such as orange, lime, and lemon, were among the rst character impact compounds identi ed by avor chemists [66]. 

With that said, the remainder of this chapter will present a discussion of the sensory characters of numerous aroma compounds. In some cases, the sensory descriptors are fairly constant across the population. This is generally the case for character impact compounds that singly define commonly known foods or food ingredients. For example, most people know eugenol as dove-like or vanillin as vanilla-like. The disagreanent comes when the aroma chemical is not clearly defined... 

In recent studies, potent aroma compounds have been identified using various gas chromatography-olfactometry (GCO) techniques, such as Charm Analysis and aroma extract dilution analysis (AEDA) (7,8). The flavor compounds that are identified by these methods are significant contributors to the sensory profile. In some cases, these sensory-directed analytical techniques have enabled the discovery of new character impact compounds. However, in other instances, key aroma chemicals have been identified that, while potent and significant to flavor, do not impart character impact. For example, in dairy products, chocolate, and kiwifmit, these flavor types appear to be produced by a complex blend of noncharacterizing key aroma compounds. 

In the case of pineapples, the 12 odorants listed in Table 16.7 were dissolved in water in concentrations equal to those determined in the fruit [50]. Then the odour profile of this aroma model was evaluated by a sensory panel in comparison to fresh pineapple juice. The result was a high agreement in the two odour profiles. Fresh, fruity and pineapple-like odour notes scored almost the same intensities in the model as in the juice. Only the sweet aroma note was more intense in the model than in the original sample [50]. In further experiments, the contributions of the six odorants showing the highest OAV (Table 16.7) were evaluated by means of omission tests [9]. The results presented in Table 16.8 show that the omission of 4-hydroxy-2,5-dimethyl-3(2H)-furanone, ethyl 2-methylbutanoate or ethyl 2-methylpropanoate changed the odour so clearly that more than half of the assessors were able to perceive an odour difference between the reduced and the complete aroma model. Therefore, it was concluded that these compounds are the character-impact odorants of fresh pineapple juice. 

Boelens, M.H. and van Gemert, L. (1993) Volatile character-impact sulfur compounds and their sensory properties, Perfumer Flavorist, 18(3), 29-39. 

Preininger, M., Warmke, R., Grosch, W. (1996) Identification of the character impact flavour compounds of Swiss cheese by sensory studies of models. Z. Lebensm. Unters. Forsch. 202, 30-34... 

Blank, 1., Sen, A., Grosch, W. (1992) Sensory study on the character-impact flavour compound of dill herb (anethum graveolens L.). Eood Chem. 43, 337-343... 

Mayer, F., Czerny, M., Grosch, W. (2000) Sensory study on the character impact aroma compounds of coffee beverage. Eur. Food Res. Technol. 211. 272-276... 

The aroma of a food often contains well over 1(X) (up to 800) components, of which only few have sensory signifrcance. The so-called impact compounds which pronounce the character of some aromas have in general been known for a long time. Only recently have methods been developed to identify the aroma-active key components of complex aromas. 

Guth, H. (1997). Quantitation and sensory studies of character impact odorants of different white wine varieties. Journal of Agiculture and Food Chemistry 45,3027-3032 Henschke, P. Jiranek, V. (1993) Yeasts-metabolism of nitrogen compounds. In Wine. Microbiology and biotechnology, G.H. Fleet (Ed), Harwood Academic, Chur, pp. 77-... 

The characteristic flavors of food and beverages as well as the pleasing scent of perfumery products are generally the result of extremely complex multisubstance mixtures, containing several hundred compounds with different chemical structures. So in most cases, the flavor impression or scent character that we perceive as a single sensation when we enjoy one of these products is a complex sensory impression of many individual substances in specific concentration ratio. These volatile components, which are present in only minor amounts (ppm to ppt range), decisively influence the enjoyment and the acceptance of foodstuffs, perfumes, and personal care or household products. Only in rare cases are individual components ( flavor impact compounds ) responsible for odor and taste. 

I. Blank, A. Sen, and W. Grosch, Sensory study on the character-impact flavor compounds of diU herh (Anethum graveolens L.), Food Chemistry, 43 337 (1992). M. H. Boelens and L. J. van Gemert, Volatile character-impact sulfur compounds and their sensory properties. Perfumer Flavorist, 18 (3) 29 (1993). 

Organic sulphur compounds usually play a considerable role in the sensory characteristics of food and beverages, as they are frequently contributors to the character of impact-scents. Examples of these products include truffle (Diaz et al., 2003 Aprea et al., 2007), garlic and onion (Yan et al., 1993 Bocchini et al., 2001), cooked meat (Hinrichsen and Pedersen, 1995 Andres et al., 2002 Carrapiso et al., 2002), coffee (Shimoda and Shibamoto, 1990 Semmelroch and Grosch, 1996), fruit juices (Winter et al., 1976 Boelens and van Gement, 1993 Hinterholzer... 

Synthesis and hydrolysis of esters Sensorial and chemical analyses of more than 60 volatile compounds showed that during MLF of red wines the main character affected was the fruity note, which is related to fatty acid ethyl esters (Antalick et al. 2012). LAB are able to modify these compounds as they may degrade or synthesize them from fatty acids (Costello et al. 2013), with the concomitant reduction or intensification of the fruity note (Sumby et al. 2013). Actually, the phenomena underlying the variability of the impact of MLF on the fruity note of red wines are more complex than a simple strain effect. These variations reflect a bacteria-yeast-wine triptych in which each component is irr5)ortant. It is illusory to presume that a given aromatic impact can be ensured by the use of a particular bacterial strain (Antalick et al. 2012). 

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