Odor thresholds pineapples

OAVs are calculated on the basis of odour threshold values which have been estimated in a medium that predominates in the food, e.g. water, oil or starch. As an example, the OAVs of the odorants of pineapples are listed in Table 16.7. 

The volatiles of fresh pineapple (Ananas comosus [L] Merr.) crown, pulp and intact fmit were studied by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The fnjit was sampled using dynamic headspace sampling and vacuum steam distillation-extraction. Analyses showed that the crown contains Cg aldehydes and alcohols while the pulp and intact fruit are characterized by a diverse assortment of esters, h rocarbons, alcohols and carbonyl compounds. Odor unit values, calculated from odor threshold and concentration data, indicate that the following compounds are important contributors to fresh pineapple aroma 2,5-dimethyl-4-hydroxy-3(2H)-furanone, methyl 2-methybutanoate, ethyl 2-methylbutanoate, ethyl acetate, ethyl hexanoate, ethyl butanoate, ethyl 2-methylpropanoate, methyl hexanoate and methyl butanoate. 

Fresh-ethereal, fruity-floral odor of very poor tenacity. The fruity notes being apple-pineapple-like, while the floral character is more of a general lift of sweetness (Arctander, 1967). The flavor is ethereal, fruity, rum, weak (Chemisis, 1998). The odor threshold given by Flath et al. (1967) was 57 ppb. 

The odor is powerful and diffusive, ethereal-fruity, apple-like with a remote resemblance to pineapple (Arctander, 1967). The flavor is described as juicy, estery, blueberry, tropical and apple (Chcmisis, 1999). An odor threshold of 5 ppb was given by Flath et al. (1967) and a flavor threshold of 94ppb by Keith and Powers (1968). 

It is described as pineapple, banana, fruity. The odor threshold in water was 1 ppb according to Takeoka et al. (1995). 

The flavor is fruity, pineapple, green, apple skin (Chemisis, 1998). The odor threshold given by Takeoka et al. (1998) is 25 ppb in water. 

The odor is warm-fruity, caramellic-sweet with emphasis on the caramellic note in the dry state, while solutions of maltol show a pronounced fruity, jam-like odor of pineapple, strawberry-type. Depending of the solvent, sometimes more balsamic, pine-like with fruity undertones (Arctander, 1967). The measured flavor threshold in water is 20.0ppm (Brule et al, 1971) or 7.1 ppm (Keith and Powers, 1968). 

The compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol, I in Formula 4.67) is the corresponding degradation product from the 6-deoxy-L-mannose (rhamnose) (Formula 4.69). Furaneol can also be formed from hexose phosphates under reducing conditions (cf. 4.2.4.4.6) and from C-3 fragments (cf. Formula 4.47). With a relatively low odor threshold value, furaneol has an intensive caramel-hke odor. It is interesting that furaneol is also biosynthesized in plants, e. g., in strawberries (cf. 18.1.2.6.9) and pineapples (cf. 18.1.2.6.10). 

The tropical category is one of the most important areas for new discoveries of key impact flavor compounds. Analyses of passion fruit and durian flavors have produced identifications of many potent sulfur aroma compounds (18). Among these is fropathiane, 2-methyl-4-propyl-l,3-oxathiane, which has an odor threshold of 3 ppb (15). For pineapple, 2-propenyl hexanoate (allyl caproate) exhibits a typical pineapple character (11) however, Furaneol, ethyl 3-methyl-thiopropionate, and ethyl-2-methylbutyrate are important supporting character impact compounds (31). The latter ester contributes the background apple note to pineapple flavor. Another character impact compound, allyl 3-cyclohexyl-... 

CsHgOj, Mr 128.13 cryst., mp. 79-80 °C odor resembling caramel, in dilute solution pineapple- and straw-berry-like olfactory threshold in water 40 ppt. LD50 (rat p.o.) 1660mg/kg. An important flavor compound, occurring naturally in pineapples, strawberries, raspberries, etc., sometimes as the glucoside. It is also formed thermally from deoxyhexoses, e. g., in coffee. For production, see... 

In addition to its inherent sensory properties, reaction of the acid and components in the wine may also have sensory impact. Oxidation of sor-bate-treated wines may lower the sensory threshold. Thus, sorbated wines should be sulfited, stored and bottled under low-oxygen conditions. Further, the compound is not recommended for wines destined for long-term aging. De Rosa et al. (1983) report a celery-pineapple-like odor they attributed to ethylsorbate in 1-year-old sparkling wine. 

Fruits and vegetables (e. g., pineapple, apple, pear, peach, passion fruit, kiwi, celery, parsley) contain unsaturated Cn hydrocarbons which play a role as aroma substances. Of special interest are (E,Z)-l,3,5-undecatriene and (E,Z,Z)-1,3,5,8-undecatetraene, which with very low threshold concentrations have a balsamic, spicy, pinelike odor. It is assumed that the hydrocarbons are formed from unsaturated fatty acids by P-oxidation, lipoxygenase catalysis, oxidation of the radical to the carbonium ion and decarboxylation. The hypothetical reaction pathway from linoleic acid to (E,Z)-l,3,5-undecatrieneis shown in Formula 5.25. 

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