Fruitiness, cheese

Straight-chain, saturated aliphatic acids are found in many essential oils and foods. These acids contribute to aromas, but are not important as fragrance substances. In flavor compositions, aliphatic acids up to Cio are used to accentuate certain aroma characteristics (C3-C8 for fruity notes C4, C6-C12 for cheese flavors). However, straight-chain and some branched-chain aliphatic acids are of... 

CH3(CH2)2C00CH2CH3, C6H12O2, Mr 116.16, 6 7ioi.3kPa 121-122 °C, df 0.8785, 1.4000, occurs in fruits and alcoholic beverages, but also in other foods such as cheese. It has a fruity odor, reminiscent of pineapples. Large amounts are used in perfume and in flavor compositions. 

Fruity flavor in dairy products is the result of ethyl ester formation, usually catalyzed by esterases from psychrotrophic or lactic acid bacteria. Ester formation by P. fragi involves liberation of butyric and ca-proic acids from the one and three positions of milk triglycerides and the subsequent enzymatic esterification of these fatty acids with ethanol (Hosono et al. 1974 Hosono and Elliott 1974). Consequently, among the esters formed, ethyl butyrate and ethyl hexanoate predominate. Pseudomonas-produced fruity flavor can occur in fluid milk, cottage cheese, and butter. 

Fruity flavor in Cheddar cheese is also associated with high levels of ethyl butyrate and ethyl hexanoate (Bills et al. 1965). However, this defect is usually caused by esterase activity from lactic acid bacteria, especially S. lactis and S. lactis subsp. diacetylactis (Vedamuthu et al. 1966). Fruity-flavored cheeses tend to have abnormally high levels of ethanol, which is available for esterification (Bills et al. 1965). Streptococcal esterase activity in cheese is affected by the level of glutathione, which suggests a dependence on free sulfhydral groups for activity (Harper et al. 1980). 

Esters. Esters are extremely important aroma compounds and there are many reports that esters are biosynthetic products of bacterial action. Thus, the fruity flavor defect sometimes found in cheddar cheese is due to the presence of esters, principally ethyl butyrate and ethyl caproate (25). Similar esters can be found in beer in which both fusel alcohols and the short chain fatty acids, acetic and butyric, are also present. These materials can undergo esterification, which in this case is mediated by the enzyme alcohol acetyltransferase present in the yeast used for beer fermentation (26). There are a number of esters present in wine which are metabolically produced by the yeast. Of these,... 

A series of ethyl esters of fatty acids, from butanoate to tetradecanoate, were identified in the EMB. Two esters, ethyl oc-tanoate and ethyl nonanoate, were found in Romano cheese. Esters are important flavor compounds in cheeses however, a high concentration of esters may cause a "fruity" defect in cheese flavor, y- and 6-dodecalactone were identified in the EMB sample as well as in Romano cheese. Lactones are well distributed in food flavors. 

The odor is powerful, choking when undiluted, but becomes tolerable in extreme dilution, almost pleasant fruity, fermented with a peculiar note resembling that of roasted cocoa or coffee (Arctander, 1967). For Motoda (1979), it is apple or malt. Fors (1983) mentions other odor descriptions as burnt, sickly for GC eluates, musty, fruity aromatic at 100°C becoming burnt cheese at 180°C. It is described as fermented, pungent, fruity at a sniffing port in a headspace/GC analysis of freshly roasted coffee (Holscher and Steinhart, 1992a). Like C.ll, it is a key component in a brew with a high aroma impact (Pollien et al., 1998). The flavor of the (R)-isomer is chocolate-like (Chemisis, 1971). 

The flavor is fruity-red fruit, gooseberry, slightly blue cheese (Chemisis, 1993),... 

This acid has a particularly pungent and acrid odor reminiscent of Roquefort cheese and of other cheeses. The taste is acrid-acid but becomes fruity-sour below 10 ppm (Arctander, 1967). By GC-olfactometry, the odor perception, in the evaluation of the aroma of a roasted Columbian coffee, is sweaty, fermented together with the 3-methyl isomer, the contribution to coffee flavor is very important (Holscher et al., 1990). In the aroma of a green coffee, it is described as weak, fermented (Holscher and Steinhart, 1995). Karl et al. (1992) showed that the enantiomers have different odors, the (R)-isomer being cheesy and the (5)-isomer fruity. 

Compounds considered to have only minor roles in. saffron aroma [tog.(FD factor.s) < I ] were described as sour, dark chocolate (unknown, no. 1), buttery, cream cheese 2,3 butanedione, no. 3), plastic water bottle (unbiown. no. 4), vinegar, acidic (acelic acid, no. 11), stale, soapy (utiknown, no. 42), fruity, stale (unknown, no. 50) and cotton candy, strawberries [4-hydroxy-2,5-dimeihyl-3(2//)-furanone, no. 59], With its low threshold compound no. 59 is an important component of several foods (ISJ ). 

Traditionally fermented dairy products have been used as beverages, meal components, and ingredients for many new products [60], The formation of flavor in fermented dairy products is a result of reactions of milk components lactose, fat, and casein. Particularly, the enzymatic degradation of proteins leads to the formation of key-flavor components that contribute to the sensory perception of the products [55], Methyl ketones are responsible for the fruity, musty, and blue cheese flavors of cheese and other dairy products. Aromatic amino acids, branched-chain amino acids, and methionine are the most relevant substrates for cheese flavor development [55]. Volatile sulfur compounds derived from methionine, such as methanethiol, dimethylsulflde, and dimethyltrisul-fide, are regarded as essential components in many cheese varieties [61], Conversion of tryptophan or phenylalanine can also lead to benzaldehyde formation. This compound, which is found in various hard- and soft-type cheeses, contributes positively to the overall flavor [57,62]. The conversion of caseins is undoubtedly the most important biochemical pathway for flavor formation in several cheese types [62,63]. A good balance between proteolysis and peptidolysis prevents the formation of bitterness in cheese [64,65],... 

Acids Fatty acids production is governed by the initial composition of the must and by fermentation conditions and have been described with fruity, cheese, fatty, and rancid notes (Rocha et al., 2004). The most abundant acids in Rojal wines were butyric acid, isobutyric acid, isovaleric acid, hexanoic acid, octanoic acid and decanoic acid. The contents of 6, 8, and 10-carbon atom fatty acids, were in agreement with those found by Garcia-Carpintero et al., 2011a,b in wines made with others grape varieties and fermented in the same conditions. 

Valeric acid (penta-noic acid) Fatty, earthy, putrid acidic, sweaty, cheesy odor, sharp, acidic, mUky cheese, slightly fruity. Megasphaera/Brettanomyces/Clostridium spps. 

The butter-like note of unripened cheese can still be detected in Camembert and Emmentaler, but the intensity is lower, because other aroma substances formed during ripening become evident. Thus, Camembert also has mushroom-like, sulfurous and flowery notes and Emmentaler, nutty, sweet and fruity notes. In comparison with unripened cheese, the taste profile is extended to include a glutamate note and in the case of Emmentaler, an additional and characteristic sour/pungent impression. 

Soft fatty slightly green-fruity cream, milk, cheese-like and green melon... 

Among esters, ethyl acetate was the most abundant component. Ethyl esters of odd-numbered acids from C2 to Cig predominated with respect to the methyl and butyl derivatives. Ethyl esters are considered to contribute to the typical fruity note of the cheese. 

Further, the results obtained enabled the correlation of the composition of the volatile fraction of Parmigiano-Reggiano cheese with sensory attributes [42], This subsequent investigation evidences the significance of the flavor in deflning the quality of a food product and, in addition, the contribution of the different volatile compound classes or of the individual substances to the sensory attributes. For example, esters, particularly methyl butanoate, ethyl hexanoate, and isobutyl acetate, are found to be positively related to the fragrant and fruity notes of aged cheese. Short-chain methyl-branched alcohols, secondary products of proteolysis, contribute to a positive maturation component of the aroma, in opposition to the sharp stimuli of free fatty acids (Fig. 6). 

A range of acids and alcohols are generated from the different pathways detailed above, thereby providing potential substrates for esterification reactions. Many esters, most generally associated with fruity flavors, are found in fermented foods. LAB esterases can catalyze the formation of esters from acids and alcohols (Liu et al. 2004 Holland et al. 2005). In cheese, acids are present in relatively high concentrations (10 to 10" pg/g), while ethanol, the main alcohol detected (McGugan et al. 1975), is present in low amounts. Ethanol has been shown to be in concentrations limiting the synthesis of ethyl esters in cheeses such as Emmental (Richoux et al. 2008) and Cheddar cheese (Urbach 1995 Liu et al. 2004). 

The aroma substances that comprise flavors are found in nature as complex mixtures of volatile compounds. A vast majority of volatile chemicals that have been isolated from natural flavor extracts do not provide aroma contributions that are reminiscent of the flavor substance. For instance, n-hexanal is a component of natural apple flavor (1) however, when smelled in isolation, its odor is reminiscent of green, painty, rancid oil. Similarly, ethyl butyrate has a nondescript fruity aroma although it is found in strawberries, raspberries, and pears, it does not uniquely describe the aroma quality of any of these individual fruits. It has long been the goal of flavor chemists to elucidate the identity of pure aroma chemicals that have the distinct character impact of the natural fruit, vegetable, meat, cheese, or spice that they were derived from. Often, these are referred to as character impact compounds (2). 

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