6-Off-Flavors and Taints in Foods Flashcards
How Sensory evaluators differentiate off-flavor testing
- Improved sensitivity descriptors or scale of intensity
- experience, ability to describe, or sensitivity to the stimulus
Methods to distinguish off-flavors
- when source is known - use panelist sensitive to flavor defect
- 30 people use triangle test
- Using discrimination test and do it rapidly
- Get as much information as possible and combine with hedonic test
- Using Level of significance (Statistical Method)
- Don’t ignore minority opinion
Sources of Food Taints
- Airborne
- Waterborne
- Disinfectants, Pesticides, and Detergents
- Packaging
How airborne taints goes into the food
- Production
- Manufacturing
- Storage
Barny/Cowy off-flavors are formed due to _______
Poor Ventilation
Challenge of Airborne sources taints are
- Difficult to identify
- May occur randomly
- Chemicals occur at low threshold and difficult to isolate and identify
Chloroanisole cause _____ off-flavor and Chlorophenol cause _____ off-flavor
Musty ; Medicinal taints
2 Sources of Waterborne Taints
- Environment
- Major ingredients in food processing
Biological and Chemical factors that cause waterborne taints
- Bacteria and Algae
- Kerosene
- Iodine
- Geosmin
- Isoborneol
Cause of Disinfectants, Pesticides, Detergents taints in foods is
- Negligence by end-user
- Error in manufacturing part during cleaning
Risk of contamination can increase along with ________
Storage time
2 genetic type that cause off-flavors
Swine and Ovine
The differences between swine and ovine off-flavors
Swine - Severe impacts to industries- persisting problem - onion sweaty manure - like notes - 92% female can detect - Prevent by vaccination or breeding Ovine - actual flavor of mature ovine animal - Mutton or Sweaty notes
at which level (ppb) bromophenol become desirable flavor
low level ( 3ppb )
Higher bromophenol compounds cause _______-like taints
Iodine
Off-flavors that is caused by chemical changes
- Lipid Oxidation
- Non-enzymatic Browning
- Photo-induced off-flavors
- Enzymatic flavor Changes
Characteristic of lipid oxidation off-flavors are
- Stale
- Cardboard
- Tallowy
- Metalic
- Painty
- Fishy
6 factors of lipid oxidation that cause off-flavors are
- Length of the C-chain
- Presence of the trace metals ( Co2+, Fe2+, and Cu2+ )
- Level of Water activity
- Temperature
- Light exposure
- Presence of antioxidants
Light cause _______ and _______ which results off-flavors
- Protein degradation
- Lipid Oxidation
How to prevent photo-induced off flavors
- Packaging with light impermeable bottles/ cans
- Pre-processing of hops - reduction to make saturated isohumulones
Enzymatic Flavor Changes common cause
- Lipoxygenase
- Lipase
- Protease
Lipoxygenase involved in _________ of unsaturated fatty acid
autooxidation
Lipoxygenase mechanism that cause off-flavors
Tissue damage - decompartmentalization - exposure
Method to prevent lipoxygenase deteroriation
Blanching ( high temperature inactivate the enzyme )
Milk lipase perferentially cleave _______ from Traicylglycerol
Butyric Acid
Prevention of Microbial off-flavors
- Heating
- Irradiation
- Addition of chemical preservative
- Addition of antimicrobial agent
3 main cause of microbial off-flavors
- Fermentation goes wrong
- Microbial enzyme
- growth of microbes in food
How microbes cause off-flavors in fresh fish
Trimethylamine oxide goes into trimethylamine due to bacterial enzymes
Microbes that cause “earthy” taints
Molds and Actinomycetes
Hypopichia burtanii cause _____-like smell due to ________ content
Plastic ; Cinnamon
Malty-notes off flavors are cause by __________ bacteria
Lactobacillus maltaromicus
Malty-notes off flavors are cause by __________ bacteria
Lactobacillus maltaromicus
