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Analysis of crab meat volatiles as possible
spoilage indicators for
blue crab(Callinectes sapidus) meat
by gas chromatography–mass spectrometry
Food Chemistry
Paul J. Sarnoski, Sean F. O’Keefe ,
Michael L. Jahncke,
ParameswarakumarMallikarjunan ,
George J. Flick
授課老師 : 邱素芬 老師學 生 : 王凱澤 B005020027
吳伊証 B995020006
Introduction
Seafood is more perishable, compared with other
muscle foods such as beef, pork, chicken, etc.
Poor handling practices
cause deterioration in fish and shellfish → the consumer(Ashie, Smith, & Simpson, 1996).
Introduction
Crab meat = free amino acids
+ high moisture content
+ loose connectivity between the collagen fibers
→ Microbial growth = Volatile → Indicator of spoilage
(Suyama & Konosu, 1987).
The objective of this study
→ Analytical method rapidly and normally
Materials and methods
Blue crab samples for GC–MS analysis
Blue Crab (Callinectes sapidus)界: 動物界 Animalia
門: 節肢動物門 Arthropoda
綱: 軟甲綱 Malacostraca
目: 十足目 Decapoda
科: 梭子蟹科 Portunidae
屬: 美青蟹屬 Callinectes
種: 藍蟹 C. sapidus
(WIKI)
Materials and methods
Blue crab samples for GC–MS analysis
Chesapeake Bay
The harvest season
→ from April to October
Materials and methods
Blue crab samples for GC–MS analysis
Cooked under pressure
at 1210C for 7–10 min.Blue Crab
Seal- Paking and
immediately frozen
Air cooled and
placed in refrigeration (2 C)
Completed within 2.5 h
Materials and methods
Blue crab samples for GC–MS analysis
Reference (0 day) samples
→ 1. -180C for 12–20 h
→ 2. -80 0C still freezer
Remaining samples
→ 1. 40C for 4,5,6 and 7 days
→ 2. -180C for 12–20 h
→ 3. -80 0C still freezer
Materials and methods
Volatile compound analysis
Solid-phase microextraction–gas chromatography–mass spectrometry
(SPME–GC–MS)
Materials and methods
Volatile compound analysis
Solid-phase microextraction–gas chromatography–mass spectrometry
(SPME–GC–MS)StableFlex™ fiber (65 um PDMS / DVB)
Injection port 270 0C for 0.5 hour.
Adsorbed Volatiles
→15 min at ambient temperature (~210C)
or →with the vial submerged
in boiling water (99.7 0C)
Fiber removed for 4 mins.
Materials and methods
15 min at temperature (~210C) Vial submerged in water (99.7 0C)
Volatile compound analysis
Solid-phase microextraction–gas chromatography–mass spectrometry
(SPME–GC–MS)
Materials and methods
Volatile compound analysis
SPME-GC-MS :For scan mode
m/z → 15-450
For SIM (Selected ion monitoring) mode
m/z → 15, 30, 42, 58, 59, 62, 63, 89, 90, and 117.
All sample groups were run in triplicate.
Especially for low concentration chemical compounds
Materials and methods
Quantitative analysis for spoilage compounds
Quantitative(Standardization)values (Sigma–Aldrich)
→ Five sample of Ammonia, TMA, and Indole.
Aqueous solutions of the standards
→ Comparison of retention and positive identification
Materials and methods
Microbial and sensory analysis
Initial bacterial load
→ AOAC approved methods( FDA Bacteriological Analytical Manual)
25 g portions + 225 mL sterile 0.1% peptone buffer
(dilution X 10)
2 min 230 RPM
35 0C for 48 h.
Aerobic plate counts (APC)
→ per gram of crab (cfu/g).
Materials and methods
Microbial and sensory analysis
Spectrum™ Descriptive Analysis Method
(Meilgaard, Civille, & Carr, 2007)
8–12 months
6 member trained sensory panelists
Classifications
High pass, mid-pass, low pass,
low fail, and high fail
Sweet, sour, bitter, salty,
ammonia, card boardy,
Materials and methods
Microbial and sensory analysis
The Result of Microbial and sensory analysis
The References and Comparing of Chemical analysis
Materials and methods
Statistical analysis
Analysis of the GC–MS data
SAS Institute
→ ANOVA
α = 0.05
Significance using a **Fisher’s LSD**
Results and Discussion
scan mode
Results and Discussion
SIM mode
Results and Discussion
Microbial and sensory analysispredict
Results and Discussion
Indicator of spoilage in some fishery products (USDC, 2009)
→ Ion-selective electrode (ISE)
but this technique measures ‘‘apparent ammonia”
→ Not only ammonia (Pivarnik, Ellis, Wang, & Reilly, 2001)
scan mode
SIM mode
Results and Discussion
Used as an indicator of spoilage in marine species
Range from 3.8 - 15.3 ppm in frozen crab meat (Yerlikaya & Gokoelu, 2004)
scan mode
SIM mode
Sample TMA peak from water HS - SPME
Crab meat contains roughly 80% moisture
Avoid water-derived
background fragments
Results and Discussion
TMA may be a more receptive indicator of
the earlier stages of spoilage.
Results and Discussion
Used as an indicator of spoilage in shrimp(Snellings et al., 2003)
scan mode
SIM mode
Sample DI - SPME
Insufficient concentrations of indole
were volatilized to be detected.Able to be detected
without heating
(99.7 0C)
Results and Discussion
Agrees well with sensory and APC group
classification.
Good chemical indicator of microbial
growth in crab meat.
Results and Discussion
Dimethylsulfoniopropionate (DMSP) → Dimethyl sulfide
微生物
Results and Discussion
Highest for day 6 samples and then decreased for the day 7 samples.
Sulfur metabolizing microorganisms may have been more active at
this point, and by day 7 became less active in the crab meat matrix.
The enzyme responsible for the breakdown reached its maximum
activity on day 6.
Results and Discussion
Ammonia
Rapidly and normally analytical method.
TMA
may be a more receptive indicator of the earlier stages
of spoilage.
Indole
Good chemical indicator of microbial growth in crab
meat.