OBJECTIVES 1. Flavor – significance; 2. Food taste; 3. Food aroma.

1. FLAVOR OBJECTIVES 1. Flavor – significance; 2. Food taste; 3. Food aroma.

2. FLAVOR 1 Major flavor-forming processes infoodstuffs

3. FLAVOR PERCEPTION 3

4. FLAVOR 4 Perception of flavor – taste, aroma, texture Trigeminal nerve - texture Chorda tympani and facial nerve- taste V1 –  ophthalmic nerve V2 –  maxillary nerve V3 –  mandibular nerve

5. FLAVOR 5 Perception of flavor – taste, aroma, texture Olfactory system – around 100 millionsreceptors. Olfactory nerve 1. Olfactory bulb 2. Mitral cells 3. Bone 4. Nasal epithelium 5. Glomerulus 6. Olfactory receptor cells Bulbs Ortonasal detection – directly through the nasal cavity Retronasal detection – through the mouth (mastication) and then nasal cavity

6. ! FLAVOR PERCEPTION 6 Flavor perception. Relation between structure and flavor 1. Taste perception – 4(5) major tastes: salty, sweet, bitter, sour+ umami also some sensations – cooling effect, metallic taste, pungent, astringency 25 milliseconds – response time

7. FLAVOR PERCEPTION 7 Flavor perception. Relation between structure and flavor

8. FLAVOR PERCEPTION 8 Tastes 1.1. Salty – presence of ions(principally NaClbutLiCl also is percepts as saltysubstance); passing of the ions through specific membrane channels Cations – reason for the salty taste; Anions – modifying and sometimes masking it. ornithine taurine

9. FLAVOR PERCEPTION 9 Tastes 1.2. Sweet – formation of сАМР after activation; AH/B theory G protein-coupled receptors T1R2+3 and T1R3 Sweet receptors g- intensity of sweetness Relation of the sweet taste of cyclamate and it’s structure

10. FLAVOR PERCEPTION 10 Tastes 1.2. Sweet – relation between sweet taste and structure of saccharin and derivatives

11. FLAVOR PERCEPTION 11 1.2. Sweet – relation between sweet taste and structure of substances

12. FLAVOR PERCEPTION 12 Tastes 1.3. Sour – due to presence of H+ (H3O+); receptors – potassium ion channels on the taste cells; Organic acids – more profound effect on sour taste than inorganic

13. FLAVOR PERCEPTION 13 Tastes 1.4. Bitter taste – characteristic for great number compounds (many of them without any physical or chemical similarities in the structure) - existence of several theories – presence of more receptors for bitter taste; lack of receptors for the bitter taste Detected at concentrations 0.0016% (4.10-5mol) Sour tatse – 0.007% HCl Salty – 0.25% NaCl Sweet – 0.5% sucrose (but perception for saccharine – second after quinine) quinine naringin hesperidin rutinose

14. FLAVOR PERCEPTION 14 Tastes 1.5. Umami (“delicious”) taste – MSG (mono sodium glutamate) and glutamates Kikunae Ikeda – 1908 was the first to discover it (brown seaweeds, Laminaria japonica) (umai – delicious; mi – taste) Tricholomic acid Ibotenic acid Produced by some fungi Nucleotides with flavor activity IMP – inosine monophosphate; GMP - guanosine monophosphate XMP – Xanthosine monophosphate Synergistic effect between the two groups

15. FLAVOR PERCEPTION 15 Perceptions and feelings 1.6. Other sensations – cooling effect (-) menthol (1R,2S,5R) Transient receptor potential cation channel subfamily M8 (TRPM8) – cold feeling

16. FLAVOR PERCEPTION 16 Perceptions and feelings 1.6. Other sensations – pungency, hotness myrosinase Allyl isothiocyanate (horseradish) sinigrin transient receptor potential cation channel subfamily V member 1 (TrpV1)

17. FLAVOR PERCEPTION 17 Perceptions and feelings 1.6. Other sensations – taste modifications 1). Leaves of a tropical plant Gymnema sylvestre (gymnemagenin) – suppress the ability to taste sweetness (several hours); sugar seems like sand in the mouth. 2). The berries of a West African shrub (Synsepalum dulcificum) – miracle fruit had a protein, a substance which changes the sour taste into sweet.

18. FLAVOR 18 Food aroma Aroma substances; key odorants Around 7100 compounds (data from 1999) found in 450 foodstuffs; Around 7-8% from them – key odorants; H. Maarse and R.Belz (1983) give approximate number of flavor substances in: beef (boiled, cooked)- 486; beer-562; butter-257; coffee-790; grape-466; orange-203; tea-541; tomato- 387 and wine (white)-644. Special attention is paid to aroma substances present in higher concentration and to those which give the specific aroma (key odorants). Isolation, Separation and Identification of Volatile Compounds in Aroma Research Hardcover– Nov 30 1982 by H. Maarse, R. Belz, 1983, Berlin, Springer.

19. FLAVOR 19 Substances giving a characteristic aroma (key odorants) 1-p-menthene-8-thiol geosmin geranial filbertone neral 2-furfurylthiol Raspberry ketone

20. ! FLAVOR 21 Major flavor-forming processes infoodstuffs Threshold value (odor threshold) – limit of detection – the lowest concentration, at which the characteristic aroma is recognized Aroma value (Ах) Ax = Cx / ax; - Cx – concentration - ax – odor threshold

21. FLAVOR 22 Major flavor-forming processes infoodstuffs Threshold value (odor threshold) – limit of detection – the lowest concentration, at which the characteristic aroma is recognized Variation of the threshold value depending from the matrix

22. FLAVOR 23 Major flavor-forming processes infoodstuffs

23. FLAVOR 24 Major flavor-forming processes infoodstuffs – Maillard reaction From 1 to 5 (table – first column): key odorant and responsible for the smell of the French fries

24. FLAVOR 25 Major flavor-forming processes infoodstuffs

25. FLAVOR 25a Aroma compounds in bread

26. FLAVOR PERCEPTION 26 Food aroma 2. Aroma perception - significance - Theories explaining perception of the aromas: chemical (adsorption-desorption processes); physical-chemical (effect of the dipole moments in the molecules); vibrational (oscillation, vibration of the bonds); enzymatic, etc.

27. FLAVOR 27 Food aroma Caraway Spearmint 3-hexenol (CH2OH-CH2-CH=CH-CH2CH3) cis- green, some fresh aroma; trans- floral, chrysanthemums

28. FLAVOR PERCEPTION 28 Food aroma 3. Relation between aroma and chemical structure - parameters influencing the specific food aroma Lipophilicity; Hydrogen bonds; Electronic factors – presence of electron pairs, π-bonds; Steric factors, etc.

29. FLAVOR PERCEPTION 29 Food aroma. Relation between structure and aroma 3 major cases found: - Different structures having same (or resembling) aroma aroma of fried foodstuffs aroma of cocoa

30. FLAVOR PERCEPTION 30 Food aroma. Relation between structure and aroma 3 major cases found: - Similar structures having different aroma chemical aroma, hydrogen sulfide aroma of cooked meat

31. FLAVOR PERCEPTION 31 Food aroma. Relation between structure and aroma 3 major cases found: - Similar structures having same (or resembling) aroma aroma of popcorn aroma of green peppers

32. FLAVOR PERCEPTION 32 Food aroma. Relation between structure and aroma - Smell of burnt – presence of polycarbonyl compounds (diacetyl, glyoxal etc.)or α, β unsaturated aldehydes (acrolein etc.) - Aroma of caramel

33. FLAVOR PERCEPTION 33 Food aroma. Relation between structure and aroma - aroma of fresh tomatoes similar structure

34. FLAVOR PERCEPTION 33 Food aroma. Relation between structure and aroma similar structures – different thresholds Odor thresholds of alkyl pyrazines (according to Wagner et al., 1999). The odor threshold in pmol / L air is given in brackets Dilution analyses suggested that compounds which appear with a high odor intensity are only P7 and P16 in addition to P5, P13 and P17

35. FLAVOR 34 Flavoring substances Natural, nature-identical and artificial (synthetic)

36. FLAVOR 35 Flavoring substances - use Natural, nature-identical and artificial (synthetic)

37. FLAVOR 36 Flavoring substances - synthesis Acetyl pyrazines Alkyl and acetyl pyrazines

38. FLAVOR 38 Natural, nature-identical and artificial (synthetic)

39. Aroma of the Strecker aldehydes 39

40. Aroma of the Strecker aldehydes 40

41. Aroma of the Strecker aldehydes 41

42. Aroma of the Strecker aldehydes 42