Potent Odorants of French Fries

Transcription

1 Potent dorants of French Fries Conceptual representation of the Maillard reaction Reactive intermediates Formation of flavour Formation of colour Analytical aspects

2 Pathways of Flavour Formation during Food Processing REDUCIG REDUCIG SUGARS SUGARS AMI AMI ACIDS ACIDS Reductones Reductones Dicarbonyls Dicarbonyls + Amino acids LIPIDS LIPIDS oxidation hydrolysis dehydration Aldehydes Aldehydes Aminoketones Aminoketones H 2 S H 3 Methylfuranolone H 2 S HETERCYLES HETERCYLES Amino Amino acids acids Peptides Peptides Sugars Sugars Trigonelline Trigonelline Ribonucleotides Ribonucleotides Vitamines Vitamines (thiamine) (thiamine)

3 Aroma compounds of processed potatoes Potato chips Mookherjee et al., 1965 Monocarbonyls Buttery et al., 1971 Pyrazines, pyridines Guadagni et al., 1972 dorants Buttery & Ling, 1972 Volatiles, odorants Deck et al., 1973 Volatiles French fries Carlin, 1983 Volatiles Carlin et al., 1986 Volatiles, alkyloxazols Wagner & Grosch, 1997 Potent odorants Potato Maga, 1994 Review

4 Potent odorants found in French fries FD-factor Maillard reaction products Lipid oxidation products Methional (E,E)-2,4-Decadienal Furaneol 2-Ethyl-3,5-dimethylpyrazine 2,3-Diethyl-5-methylpyrazine Sotolone (Z)-2-onenal 3-Ethyl-2,5-dimethylpyrazine (E)-2-onenal Dimethyltrisulphide (E,Z)-2,4-Decadienal 3-Methylbutanal trans-4,5-epoxy-(e)-2-decenal (Wagner & Grosch, Lebensm. Wiss. Technol., 30, 164, 1997)

5 Chemical structures of potent odorants found in French fries FD-factor Maillard reaction products Lipid oxidation products H S H S S S (Wagner & Grosch, Lebensm. Wiss. Technol., 30, 164, 1997)

6 Formation of potent odorants found in French fries - Strecker aldehydes - Amino acid + α-diketone Transamination Aminoketone + Aldehyde + C 2 R H H 2 + R'' R' Amino acid α Diketone CH H 2 S CH - H 2 S R R' H R'' - C 2 R R' R'' H H 2 R Strecker aldehyde + H 2 R'' R' Aninoketone H 2

7 Formation of potent odorants found in French fries - Pyrazines - H 2 + R''-CH - H 2 R H 2 R' R R' R Aninoketones Strecker aldehyde H R'' R' - H 2 R = CH 3 R' = CH 3 R'' = CH 3 R R' R'' R R' R'' (Cerny et al., J. Agric. Food Chem., 43, 2818, 1995)

8 Formation of potent odorants found in French fries - Furaneol - H H H H H R Amadori compound H a - Amino acid H H H 1-Deoxyglucosone b - H 2 H H Acetylformoine H - H 2 H H H c H H H H (Blank et al., 6th Maillard Symp. London, 1997)

9 Formation of potent odorants found in French fries - Sulphur containing compounds - S CH S H CH 3 SH H 2 Methionine Strecker aldehyde Methanethiol CH 3 SH H 2 S S S + S S S

10 Concentration of the most potent odorants found in French fries Attribute Reference compound Concentration (ug/kg) Earthy 2,3-Diethyl-5-methylpyrazine 400 Deep-fried, fatty (E,E)-2,4-Decadienal 900 Boiled potato Methional 1.0 Sweet, caramel Furaneol 125 Malty 3-Methylbutanal 30 (Wagner & Grosch, Lebensm. Wiss. Technol., 30, 164, 1997)

11 Aroma profile of French fries Attribute dour intensity dour intensity asal Retronasal Earthy Deep-fried, fatty Boiled potato Sweet, caramel Malty (Wagner & Grosch, Lebensm. Wiss. Technol., 30, 164, 1997)

12 Colour Formation of Fried Potato Crisps Conceptual representation of the Maillard reaction Reactive intermediates Formation of flavour Formation of colour Analytical aspects

13 Reaction pathways of the Maillard reaction (Hodge, 1953) Aldose sugar + Amino compound - Amino compound - water + Amino compound With or without amino compound ph < 7 Furfural or HMF -substituted glycosylamine AMADRI PRDUCT Reductones - 2H + 2H Dehydroreductones C2 + ALDEHYDES Aldols, -free polymers Aldimines, ketimines MELAIDIS - Water ph > 7 Fission products + Amino acid Strecker degradation + Amino compound + Amino compound + Amino compound E A R L Y A D V A C E D

14 Colour formation - Reactivity of sugars and their degradation products - Yang & Shin (1980): Xylose > arabinose >> fructose > glucose > maltose > lactose Hashiba (1982): Ribose > glucuronic acid xylose > arabinose > galacturonic acid > galactose > mannose > glucose >> lactose Hayashi & amiki (1986): Glycolaldehyde glyceraldehyde > methylglyoxal > glyoxal >> xylose > glucose > fructose

15 Colour formation - Reactivity of sugars and Amadori compounds - Sugar + Amino acid I Amadori compound II Brown pigments Sugar / Glycine E 550 Amadori compound E 550 Ribose 0.34 Ribulose-glycine 0.78 Xylose 0.21 Xylulose-glycine 0.81 Arabinose 0.12 Ribulose-glycine 0.78 Glucuronic acid 0.22 Fructuronate-glycine 0.68 Galacturonic acid 0.09 Tagaturonate-glycine 0.82 Galactose 0.03 Tagatose-glycine 0.62 Mannose 0.02 Fructose-glycine 0.24 Glucose 0.01 Fructose-glycine 0.24 Lactose <0.01 Lactulose-glycine 0.06 (H. Hashiba, Agric. Biol. Chem., 46, 547, 1982)

16 Formation of browning and Amadori compounds by heating glucose and β-alanine ph 9.3 ph 6.4 ph 3.5 (Hayashi & amiki, 1986) ph 9.3 ph 6.4 ph 3.5

17 Browning by the reaction of sugar or carbonyl compound with β-alanine (Hayashi & amiki, 1986) Xylose Methylglyoxal Glucose Glycolaldehyde Xylose

18 Formation of C 2 and C 3 imines generated by heating glucose and β-alanine ph 9.3 ph 6.4 ph 3.5 (Hayashi & amiki, 1986)

19 Glycine is the most reactive amino acid with respect to colour formation Amino acid Absorbance Amino acid Absorbance Glycine 1.05 Histidine 0.33 Lysine 0.62 Glutamine 0.32 Alanine 0.43 Threonine 0.25 Isoleucine 0.39 Proline 0.23 Leucine 0.37 Asparagine 0.22 Valine 0.36 Serine 0.19 Methionine 0.36 Arginine 0.18 Phenylalanine 0.33 Cysteine 0.01 Reaction conditions: D-xylose/L-amino acid (each 2.5 mmol), ph 7, reflux, 2 h; Absorbance: 450 nm (J. Ames, Chem. Ind., 362, 1986)

20 Pathways leading to melanoidin formation (Hayashi & amiki., Agric. Biol. Chem., 50, 1965, 1986)

21 Influence of the ph on colour development Colour intensity ph 7 ph 6 ph 5 ph 4 ph 3 Dehydrated extracts of pork days

22 Structure of some newly identified pigments isolated from Maillard model systems R R R H H H H H H R R R R H H H H H H H (Tressl; Ames; Arnoldi; Hofmann; 6th Maillard Symposium, London, 1997)

23 Fry colour intensity of potato crisps Colour of potato crisps is determined by the chemical composition of tubers which can change during storage (Smith, 1987) Browning of crisps at high processing temperatures is due to the Maillard reaction (Schallenberger et al., 1959) The extent of browning is correlated with the amounts of reducing sugars (RS), i.e. glucose and fructose (Gray & Hughes, 1978) Acceptable level of RS for processing of potatoes into crisps is about % of tuber fresh weight (Burton & Wilson, 1970) In high nitrogen potatoes there was more colour per unit of RS indicating that amino acids play a synergistic role (Roe et al., 1990)

24 Glutamine is the key amino acid in the fry colour development of potato crisps Amino acid Glucose concentration (%) (mg/100 g) Glutamine (1436) Arginine (320) Asparagine (1800) Valine (182) His, Pro, Tyr, Met Mixture (Khanbari & Thompson, Potato Res., 36, 359, 1993)

25 Carbon Dioxide as an Early Indicator of the Maillard Reaction Conceptual representation of the Maillard reaction Reactive intermediates Formation of flavour Formation of colour Analytical aspects

26 12 Symptoms of the Maillard reaction Chemistry Production of colour and discoloration Production of flavour and offflavour Formation of water Formation of carbon dioxide (H.E. ursten) Biochemistry Loss of biological value of protein Loss of vitamin C activity Production of toxicity Physico-chemistry Increasing reducing power Lowering of ph decreasing solubility Chelation of metals Production of fluorescence

27 Analytical indicators of the Maillard reaction ALDSE + PRTEI Immunoassays Furosine assay Loss of available amino groups Bioassays Chemical assays 1-AMI-1-DEXY-2-KETSE CML HMF DICARBYL ITER MEDIATES Volatile aldehydes + ε-pyrrolelysine C2 ( Brien & Morissey, modified) MELAIDIS Colour measurement

28 Pathways of the Maillard reaction (Hodge, 1953) Aldose sugar + Amino compound - Amino compound - water + Amino compound ph < 7 Furfural or HMF -substituted glycosylamine AMADRI PRDUCT Reductones - 2H + 2H Dehydroreductones C 2 + ALDEHYDES Aldols, -free polymers Aldimines, ketimines - Water ph > 7 Fission products + Amino acid Strecker degradation + Amino compound + Amino compound E A R L Y A D V A C E D With or without amino compound MELAIDIS + Amino compound

29 Influence of heat treatment on shelf-life Freeze-dryied tomato powder stored at 23 C K K K K Level of acceptability (K. Eichner)

30 Formation of C 2 in tomato powder depending on water activity (a w ) and temperature Kruse et al., ZLUF, 205, 31 (1997)

31 Changes of some parameters of the Maillard reaction in tomato powder at a w = 0.32 and T= 30 C Kruse et al., ZLUF, 205, 31 (1997)

32 Influence of 2 on the formation of C 2 in tomato powder at a w = 0.31 and T= 30 C Kruse et al., ZLUF, 205, 31 (1997)

33 Contribution of galacturonic acid to the formation of C 2 in tomato powder (8 weeks at a w = 0.33 and T= 30 C) Kruse et al., ZLUF, 205, 31 (1997)

34 Reactions in tomato powder after adding [1-13 C]glycine (14 weeks at a w = 0.33 and T= 30 C) Kruse et al., ZLUF, 205, 31 (1997)

35 Formation of C 2 from galacturonic acid or glucose in starch model systems (a w = 0.33, T= 30 C) GalA GalA + Citric acid GalA + Glycine + Citric acid GalA + [1-13 C]Glycine Glucose + [1-13 C]Glycine Kruse et al., ZLUF, 205, 31 (1997)

36 Challenge to Food Industry... to transform complex and perishable raw materials into stable products whilst retaining perceivable and nutritional quality.