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Questions and Answers
Which group of compounds is identified as useful for assessing freshness in fish?
What is one significant advantage of the SPME technology used for identifying freshness?
Which of the following substances primarily serves as the basis for checking spoilage in fish?
How many compounds were identified in total by SPME technology?
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What range of esters is included in the compound identification for assessing freshness?
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What role do external factors play in the accuracy of analysis results?
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What was Yagiz's comparison focused on?
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What does Misimi propose regarding the HIS technique?
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What was confirmed about the HIS system's prediction model for irradiated Atlantic salmon?
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What is suggested about the depth of research needed for the HIS technique?
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In what area does the combination of computer vision and HIS serve as a powerful tool?
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What aspect of analysis is impacted by the HIS technique?
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What is a major limitation outlined that affects the HIS technique?
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What is the disadvantage of using the K-value method for evaluating fish freshness?
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What does the K-value specifically measure in the context of fish freshness?
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What advantage does the K-value method offer for assessing fish freshness?
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Why is high precision crucial when employing the K-value method?
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Which compounds are primarily monitored to determine the K-value?
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What is a key characteristic of methods that use K-value for evaluating fish freshness?
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What was the main correlation found in the preliminary studies related to the K-value?
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What is the K-value formula used to calculate the freshness value of fish?
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What is responsible for the stiffness of fish muscles after death?
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Which compound is formed from TMAO during the spoilage of sea fish?
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What is indicated by a high K value in the context of fish spoilage?
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Within how many hours does spoilage typically begin in tropical conditions after fish is caught?
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Which of the following compounds is NOT part of the K value calculation?
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What role do digestive enzymes play in fish spoilage?
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What is a gas-sensitive hybrid gel material used for in relation to fish?
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Which of the following statements about the spoilage mechanisms in fish is correct?
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What role do TMA and TVB-N play in the analysis of fish muscle?
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Which compound is primarily associated with the spoilage of fish based on bacterial deterioration?
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What does the presence of sufficient TMAO-reducers in fish indicate?
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What is indicated by measuring the amount of TMA in fish muscle?
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What is the primary focus of Morsy et al. (2016) in relation to fish spoilage?
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Study Notes
Freshness Assessment of Fish
- Volatile Compound Analysis: Solid Phase Micro Extraction (SPME) identified 86 compounds; 20 of these are effective indicators of fish freshness, including alcohols, ketones, aldehydes, and esters (C2-C11).
- Technology Features: Non-destructive, reliable, and sensitive method; allows for quick assessment of spoilage without damaging the sample.
- Advantages and Disadvantages: High precision and accuracy required; however, it can be costly.
K-Value Freshness Indicator
- K-Value Definition: Developed as a ratio of total inosine and hypoxanthine to ATP-related compounds, indicating fish freshness.
- K-Value Calculation: Formula: K-value (%) = (HxR + Hx) / (ATP + ADP + AMP + IMP + HxR + Hx), where HxR is inosine and Hx is hypoxanthine.
- Importance of K-Value: Widely accepted for correlating ATP decomposition with fish quality; useful in monitoring freshness.
Spoilage Mechanisms
- Rapid Spoilage: In tropical climates, fish begin to spoil within 12 hours of catch; rigor mortis results in muscle stiffness post-mortem.
- Degradation Factors: Surface bacteria, digestive enzymes, and oxidation contribute to spoilage and quality degradation.
Chemical Indicators of Freshness
- Trimethylamine-Oxide (TMAO): Present in sea fish, broken down by bacteria to form TMA, serving as an indicator of spoilage.
- Bacterial Action: TMAO-reducing bacteria often present, ensuring TMA formation during spoilage.
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Monitoring Innovations:
- Gas-sensitive hybrid gel materials have been developed to monitor spoilage of fish like tilapia based on optical signal changes.
- Colorimetric sensors can detect spoilage in Atlantic Salmon by measuring levels of spoilage-related compounds such as TMA, DMA, cadaverine, and putrescine.
Summary of Chemical Changes
- TMA Accumulation: Initial muscle tissues contain minimal TMA; increased levels over time indicate bacterial deterioration and spoilage extent.
- TVB-N as an Indicator: Total Volatile Basic Nitrogen (TVB-N) levels reflect changes in fish muscle characteristics during spoilage.
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Description
Explore the analysis of Whiting Cod and Mackerel, emphasizing the use of SPME to identify compounds related to seafood freshness. This quiz covers the 86 identified compounds, focusing on the 20 key indicators including alcohols, ketones, and aldehydes. Test your knowledge on non-destructive techniques in seafood evaluation.