Trocino Lecture 6 Flashcards
Which of the following is an intrinsic trait of seafood quality?
A) Fishing methods
B) Chemical composition
C) Post-harvest management
D) Ethical implications
b
What is an extrinsic trait affecting the quality of seafood?
A) Size and yields
B) Traceability and labeling
C) Fishing and slaughtering methods
D) Freshness and shelf life
c
What are myomers in fish muscle?
A) Long muscle fibers organized in bundles
B) Bundles of short muscle fibers
C) Connective tissues surrounding muscles
D) Proteins within muscle fibers
b
Which type of protein makes up 65-75% of fish muscle proteins?
A) Sarcoplasmatic proteins
B) Myofibrillar proteins
C) Connective tissue proteins
D) Regulatory proteins
b
What is the primary energy source for white muscle fibers in fish?
A) Lipids
B) Glycogen
C) Myoglobin
D) Amino acids
b
What motor proteins are involved in muscle contraction?
A) Actin and myosin
B) Tropomyosin and troponin
C) Myoglobin and hemoglobin
D) Actin and myoglobin
a
During intense muscle activity, white muscles produce:
A) CO2 and water
B) Lactic acid
C) ATP
D) Glucose
b
What happens to fish muscle pH post-mortem?
A) It increases
B) It decreases
C) It remains constant
D) It fluctuates
b
Which process occurs when actin and myosin form stable complexes post-mortem?
A) Glycolysis
B) Rigor mortis
C) Autolysis
D) Bacterial spoilage
b
What effect does pre-slaughter stress have on rigor mortis?
A) Delays onset
B) Accelerates onset
C) Prevents rigor mortis
D) Has no effect
b
Which bacteria are commonly involved in fish spoilage within the first 7 days?
A) Escherichia coli
B) Staphylococcus aureus
C) Pseudomonas and Shewanella
D) Bacillus subtilis
c
What is the main cause of non-microbiological spoilage in fish?
A) Bacterial activity
B) Enzymatic activity
C) Fungal growth
D) Viral infection
b
TMAO degradation in fish leads to the production of:
A) Glycogen and glucose
B) Lactic acid and ethanol
C) Trimethylamine (TMA) and formaldehyde
D) Ammonia and methane
c
Which factor does NOT affect the onset of rigor mortis?
A) Muscle activity before slaughter
B) Storage temperature
C) Presence of parasites
D) Physical condition of the fish
c
High pre-slaughter activity in fish leads to:
A) Slower rigor mortis onset
B) Faster rigor mortis onset
C) No change in rigor mortis
D) Complete prevention of rigor mortis
b
Which method is NOT used for evaluating fish freshness?
A) Quality index method
B) Physical measurements
C) DNA sequencing
D) Microbiological analyses
c
What does a high level of Hypoxanthine (Hx) indicate in fish?
A) Freshness
B) Bitter taste
C) Sweet taste
D) High nutritional value
b
What causes the typical paper and mold taste in frozen seafood?
A) Protein oxidation
B) Lipid oxidation
C) Microbial growth
D) High water content
b
Which compound is associated with a metallic flavor in fish?
A) 1-octen-3-one
B) 2-trans,6-cis-nonadienale
C) 2-n-Pentilfurano
D) 3-cis-esenale
b
What is the origin of TMAO in marine fish?
A) Endogenous protein catabolism
B) Exogenous feeding
C) Both A and B
D) Neither A nor B
c
What does TMAO degrade into under anaerobic conditions?
A) DMA and MMA
B) IMP and Hx
C) TMA and formaldehyde
D) Lactic acid and CO2
c
Which chemical is NOT used to control spoilage in fish?
A) Chlorine
B) Sulfur dioxide
C) Ascorbic acid
D) Ethanol
d
What effect does gutting have on fish spoilage?
A) Increases microbial contamination
B) Reduces microbial contamination
C) Has no effect on spoilage
D) Only affects non-microbiological spoilage
b
Which bacteria is commonly associated with higher TMA production under anaerobic conditions?
A) Lactobacillus
B) Pseudomonas
C) Staphylococcus
D) Bacillus
b
What is the primary spoilage compound produced by Pseudomonas in fish?
A) TMA
B) Lactic acid
C) Ethanol
D) Methane
a
What percentage of fish muscle proteins are sarcoplasmatic proteins?
A) 10-15%
B) 25-30%
C) 40-50%
D) 60-70%
b
Red muscle fibers in fish are primarily responsible for:
A) Fast swimming activity
B) Slow swimming activity
C) Bursts of speed
D) Jumping out of water
b
What is the odor associated with 2-trans,4-cis,7-cis-decatrienale in fish?
A) Metallic
B) Fishy
C) Green leaves
D) Rancid
c
Which ketone compound is known for its liquorice flavor in fish?
A) 1-penten-3-one
B) 1-octen-3-one
C) 2-n-Pentilfurano
D) 5-Pantenil-2-furaldeide
c
During protein catabolism in fish, which amino acid is reduced to indole and pyruvic acid by bacteria?
A) Glycine
B) Tryptophan
C) Lysine
D) Alanine
b
Which enzyme is NOT involved in non-microbiological spoilage of fish?
A) Trypsin-like endopeptidases
B) Catepsin
C) Lipase
D) Amylase
d
Which of the following is NOT a freshness indicator in fish?
A) Eye pH
B) Malonaldehyde content
C) Putrescine levels
D) Water activity
d
IMP in fish muscle is responsible for:
A) Bitter taste
B) Sweet taste
C) Meat taste
D) Metallic taste
c
High levels of Hypoxanthine (Hx) in fish indicate:
A) Freshness
B) Spoilage
C) Improved taste
D) Higher nutritional value
b
The best method to control fish spoilage is:
A) High-temperature storage
B) Modified atmosphere packaging
C) Direct sunlight exposure
D) High humidity storage
b
Which method is NOT effective in reducing microbial contamination in fish?
A) Chlorine treatment
B) Modified atmosphere
C) Sun drying
D) Sea water saturated with CO2
c
What is the main factor affecting the onset of rigor mortis in fish?
A) Species of fish
B) Storage conditions
C) Pre-slaughter muscle activity
D) Fish size
c
The condition where muscle fibers break due to weak connective tissue post-mortem is called:
A) Autolysis
B) Gaping
C) Denaturation
D) Spoilage
b
The primary metabolic pathway for energy in red muscle fibers is:
A) Glycolysis
B) Beta-oxidation
C) Krebs cycle
D) Pentose phosphate pathway
b
Which protein is predominant in white muscle fibers of fish?
A) Myoglobin
B) Actin
C) Tropomyosin
D) Troponin
b
Which microorganism is NOT typically involved in fish spoilage?
A) Shewanella
B) Acinetobacter
C) Lactobacillus
D) Pseudomonas
c
The presence of biogenic amines in spoiled fish is primarily due to:
A) Lipid oxidation
B) Protein degradation
C) Carbohydrate fermentation
D) Water loss
b
What role does catepsin play in fish spoilage?
A) Oxidizes lipids
B) Hydrolyzes proteins
C) Synthesizes ATP
D) Degrades carbohydrates
b
Gut enzymes have a larger effect on spoilage when fish are captured during:
A) Spawning
B) Feeding activity
C) Migration
D) Hibernation
b
What is a common physical measurement used to evaluate fish freshness?
A) Eye color
B) Body length
C) Flesh firmness
D) Scale count
c
Which compound is a spoilage indicator in frozen fish?
A) TMA
B) DMA
C) MMA
D) Hx
b
The typical odor of spoiled fish is due to:
A) Lactic acid
B) TMA
C) Ethanol
D) CO2
b
Which process promotes lipid oxidation in fish?
A) Low temperatures
B) High humidity
C) Light exposure
D) Antioxidant supplementation
c
What is the primary cause of a rancid odor in spoiled fish?
A) Lipid hydrolysis
B) Protein denaturation
C) Lipid oxidation
D) Carbohydrate fermentation
c
