Presentation delivered to \'Introduction to Flavours and their Applications\' course hosted by Leatherhead Food Research 9 – 11 November 2010

1. The Good the Bad and the Ugly The Impact of Off-flavours and Taints on Product Quality Dr Bill Simpson Cara Technology Limited www.cara-online.com Introduction to Flavours and their Applications Leatherhead Food Research 9 – 11 November 2010

3. Consumer impact

4. Off-flavours

5. Taints

6. Prevention and controloverview

7. Definitions definitions

8. Not all off-flavours and taints are created equal definitions

9. Consumer impact “It’s different” “It’s not quite right” “I’m not sure I like this” “There’s something wrong here” “I’m worried” “Help!” Consumer impact

10. Ecomomicimpact 2010 One chemical consumer impact 2-Methyl napthalene Contaminant from cereal packaging 28 million boxes of cereal recalled

11. Flavour thresholds Positive flavours Off-flavours flavour thresholds Taints Log flavour threshold

12. Categories of off-flavours and taints Halophenols Sulphur compounds Aldehydes Peptides categories Haloanisoles Other phenolics Acids Heterocyclic compounds Esters Hydrocarbons Metals Bases

13. Origins of off-flavours origins

15. Butyric

16. Dimethyl sulphide

17. Hydrogen sulphide

18. Methanethiol

19. Dimethyl disulphide

20. Indole

21. Skatole

22. Isovaleric

23. Guaiacol

24. Styrene

25. Ethyl acetate

26. Acetaldehyde

27. ‘Sour’

28. Acetic

29. ‘Mousy’

30. ‘Mushroom’

31. 1,3-Pentadieneoff-flavours

33. Traced to combination of diacetyl and butyric acid – confirmation by GC

34. The two flavours found to act synergistically to give a flavour intensity which belied their low concentration

35. Butyric acid produced at one stage of the production processed influenced diacetyl concentrations at a later stage – two different microbiological eventsoff-flavours

37. Traced to presence of guaiacol – confirmation by GC

38. Source identified as growth of Alicyclobacillus bacteria

39. This organism can grow at very low pH values in fruit juice to cause flavour spoilage – can also produce 2,6-dibromophenol and 2,6-dichlorophenol

40. Organism survives juice pasteurization and grows in supply chainoff-flavours

42. cis-3-Hexenal

43. trans-2-Nonenal

44. trans-trans-2,4-Heptadienal

45. ‘Bitter’

46. ‘Metallic’off-flavours

48. Dimethyl sulphide

49. Furfural and related compounds

50. Beta-Damascenone

51. ‘Burnt’off-flavours

53. 2-Furfuryl ethyl ether

54. 1-Napthol

55. 3-Methyl-2-butene-1-thioloff-flavours

57. Affected almost all beers made in several breweries simultaneously

58. Traced to specific batches of malt produced after a certain date

59. Causative agent identified as a sulphur compound – 4-methyl-4-mercapto-pentan-2-one

60. Source was material derived from paint used in the maltings which reacted with yeast-derived H2S in the breweryoff-flavours

62. Predisposing factors identified before causative compound was identified analytically – 3-methyl-2-butene-1-thiol

63. Extremely odour-active – ng to pg flavour threshold

64. Long-range UV light cleaves fatty side chain from hop bitter acid – requires vitamin co-factor – side chain reacts with sulphur compound to generate MBT

65. Modified hop materials eliminate riskoff-flavours

67. Water

68. Product water

69. Process water

70. Gases

71. Environmental air

72. Process gases

73. Packaging materials

74. Environmenttaints

76. 2,4,6-Tribromoanisole

77. 2,6-Dichlorophenol

78. 2-Bromophenol

79. 2-Isobutyl-3-methoxypyrazine

80. o-Aminoacetophenone

81. 5-alpha-Androst-16-en-3-onetaints

83. 2-Methyl-isoborneol

84. 2-Isopropyl-3-methoxypyrazine

85. 2-Isobutyl-3-methoxypyrazine

86. Methyl tertiary-butyl ether (MTBE)

87. o-Cresol

88. trans-trans-2,4-Heptadienal

89. 2,6-Dichlorophenol

90. 2-Bromophenol

91. Trihalomethanestaints

93. 2,4,6-Tribromoanisole

94. 2-Methyl-isoborneol

95. 2-Isopropyl-3-methoxypyrazine

96. 2-Isobutyl-3-methoxypyrazine

97. o-Cresol and cresol derivatives

98. 2,6-Dichlorophenol and other chlorophenols

99. 2-Bromophenol and other bromophenolstaints

101. Dimethyl sulphide

102. Dimethyl disulphide

103. Dimethyltrisuphide

104. Methanethiol

105. Ethanethiol

106. Acetaldehyde

107. Various hydrocarbonstaints

109. Caused ‘illness’ and led to mass hospitalizations

110. Product withdrawn from several European markets

111. Wiped billions off the Company’s share price

112. Traced to sulphur compounds, including methanethiol, dimethyl disulphide, dimethyl trisulphide – derived from CO2 gas ingredient

113. Consumer reaction believed to have been psychosomatictaints

115. 2,4,6-Trichloroanisole

116. 2,4,6-Tribromoanisole

117. ..... and a huge number of compounds derived from inks, plasticizers, glues, lubricants etc

118. Recycling is a big risktaints

120. Analysis revealed many compounds

121. Sensory work showed that most of the compounds present did not give rise to the type of flavour identified

122. Selective extraction and GC-MS identified 6-chloro-o-cresol as the cause

123. The origin of the taint was not establishedtaints

125. Medicinal, phenolic, iodine-like

126. Identified by GC-MS as 2,4,6-trichloroanisole, together with its precursor 2,4,6-trichlorophenol

127. Concentrations of ng/l

128. Source not yet identified but likely to involve exposure to wood preservatives and the action of moulds on those preservativestaints

130. ‘Acidic’ / ‘sour’

131. 6-Chloro-o-cresol

132. 6-Chloro-2-methylphenol

133. 2-Iodophenol

134. 2,4,6-Trichloroanilinetaints

136. Screening of in-process samples

137. Screening of packaging materials

138. Screening of finished product

139. Screening of stored product

140. Screening of product in the market

141. Screening of the assessors who do the screeningprevention

142. Sensory testing prevention 2-Isobutyl-3-methoxypyrazine

144. Training with reference standards can be used to build up the required skill

145. In the brewing industry a performance assessment scheme has been operating for almost 10 years - >7,000 assessors in 450 breweriesprevention

147. Understanding of the mechanisms by which such off-flavours and taints arise in the process

148. Understanding the factors which pre-dispose a production process to problems – implementation of robust preventative measuresprevention

150. Look for patterns of flavour non-conformances to identify root causesprevention % of samples affected

152. Off-flavours are generated internally within the product

153. Taints arise externally and are carried by a vector

154. Sensory testing is the key defence with analytical techniques helping with identification of root causes

155. Myriad sources of problems but considerable literature and knowledge on the subject with knowledge of relevance to multiple industriessummary

156. Contact details Cara Technology Limited Leatherhead Enterprise Centre Randalls Road Leatherhead Surrey KT22 7RY UK Tel +44 1372 822218 Fax +44 1372 821599 www.cara-online.com bill.simpson@cara-online.com contact