Food Taints and Off-Flavours

Front Cover
M.J. Saxby
Springer Science & Business Media, 1996 - 326 pages
Contamination of food with extremely low levels of certain compounds can cause an unpleasant taste. This can result in the destruction of vast stocks of product, and very substantial financial losses to food companies. The concentration of the alien compound in the food can be so low that very sophisticated equipment is needed to identify the components and to determine its source. It is vital that every company involved in the production, distribution and sale of foodstuffs are fully aware of the ways in which contamination can accrue, how it can be avoided, and what steps need to be taken in the event that a problem does arise. This book provides the background information needed to recognize how food can become tainted, to draw up guidelines to prevent this contamination, and to plan the steps that should be taken in the event of an outbreak. The new edition has been extensively revised and updated and includes substantial new material on the formation of off flavors due to microbiological and enzymic action, and on sensory evaluation of taints and off flavors A new chapter on off flavors in alcoholic beverages has been added. Written primarily for industrial food technologists, this volume is also an essential reference source for workers in research and government institutions.

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Contents

Sensory evaluation of taints and offflavours
1
12 Thresholds and their measurement
4
13 Sensory descriptions of taints and offflavours
11
14 Principles of sensory evaluation of food
15
142 Hedonic tests
19
143 Requirements for a sensory evaluation operation
20
15 Sensory testing for taint
21
152 Diagnostic taint testing
25
References
163
Oxidative pathways to the formation of offflavours
168
62 Unsaturated lipids as offflavour precursors
170
622 Photosensitised oxidation
172
623 Factors affecting the rate of lipid oxidation
173
624 Formation of hydroperoxides offflavour precursors
181
63 Decomposition of hydroperoxides and types of offflavour compounds
186
631 Aldehydes
188

153 Preventive tainttransfer testing
26
154 Sensory quality control taint testing
30
155 Storage and shelflife testing
31
16 Ethical considerations
34
17 Future developments
37
References
38
A survey of chemicals causing taints and offflavours in food
41
22 Taints derived from known chemicals
44
222 Chlorophenols
46
223 Bromophenols
48
224 Haloanisoles
49
225 Compounds containing sulphur
53
226 Alcohols
55
227 Hydrocarbons
56
228 Esters and ethers
60
229 Amines
61
2210 Chlorinated hydrocarbons
62
2211 Carbonyl compounds
63
2212 Furans and oxygenring compounds
65
2213 Fatty acids
66
Analysis of taints and offflavours
72
32 Instrumental analysis
73
322 Separation
79
323 Identification
82
33 Sensory methods
83
333 Selection of offflavour compounds
84
334 Confirmation of the contribution of identified compounds to the offflavour
87
342 Application of dilution techniques
88
343 Odorous contaminants
95
35 Conclusions
103
Taste and odor problems in drinking water
107
43 Classifying tastes and odors
108
44 The causes of tastes and odors in water supplies
110
45 Causeandeffect relationships in drinking water taste and odor problems
114
46 Specific taste and odorcausing compounds
115
464 Chloramine
116
465 Chlorination byproducts
117
47 Treatment of specific odorous chemicals
123
48 Taste and odor treatment of offodors by chlorination and chloramination
124
49 Taste and odor treatment of offodor by ozonation
128
410 Taste and odor treatment by carbon adsorption
132
411 Summary
133
Undesirable flavors in dairy products
139
53 Transmitted offflavors
141
532 Cowy flavor
142
534 Weed flavor
143
54 Lipolyzed flavor
144
542 Microbial lipases
145
543 Flavor characteristics of lipolytic products
146
55 Microbial flavors
148
553 Fruity flavor
149
554 Green flavor
150
555 Malty flavor
151
56 Heatinduced flavors
152
57 Oxidized flavor
155
572 Reaction products
158
58 Miscellaneous offflavors
160
Acknowledgement
162
632 Ketones
202
633 Furans
206
634 Furanoid fatty acids and dicarbonyl compounds
208
635 Alcohols
210
636 Acids
212
637 Hydrocarbons
214
64 Miscellaneous offflavours and precursors
215
65 Conclusions
217
Acknowledgement
218
Packaging material as a source of taints
226
72 Standard odour and taint assessment methods
229
722 Test methods
230
723 Precautions in selecting transporting and handling samples for sensory testing
235
731 Printing ink and varnish types
236
732 Precautions to prevent odours and tainting from printed packaging
237
733 Methods for determining levels of residual solvents
239
734 Some reported odour and taint investigations
241
74 Paper and board packaging
242
75 Plastics packaging
246
76 Chlorophenols and chloroanisoles
252
77 Scalping of food aromas and flavours by packaging
254
78 Analytical methods for isolating and identifying odorous and tainting substances
256
References
260
A retailers perspective
264
82 Product recall
265
822 What is the problem?
266
823 How widespread?
267
83 Case histories
268
84 Avoidance of taint
271
Acknowledgement
273
Formation of offflavours due to microbiological and enzymic action
274
92 Milk and dairy products
275
923 Other defects
276
932 Legumes
277
933 Brassicas
279
934 Potato
280
94 Wine and beer
281
942 Beer
283
95 Meat and fish
284
96 Concluding remarks
286
Offflavours in alcoholic beverages
290
102 Beer
292
1021 Raw materials
294
7022 Processing
297
1023 Microbiological spoilage
300
1024 Packaging
303
1025 Storage
305
1026 Accidental contamination
308
103 Cider
309
1032 Processing
310
1034 Packaging
311
105 Wine and fortified wine
312
1052 Process
314
1053 Microbial spoilage
315
1055 Storage
316
Acknowledgements
317
Index
321
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