FSFS 6&7 (+THERMAL MAILLARD)

• Strecker degradation


  One of the most important flavour reactions associated with Maillard browning
• Strecker degradation


  1. Amino acids degrade (breakdown) at high temperatures or with catalysts

  2. Amino group of the amino acid reacts with the carbonyl group from a sugar molecule

  3. Produces an intermediate molecule containing nitrogen known as the Schiff base

  4. Releases water

  5. Condensation reaction

  6. Schiff base reacts further to eventual flavour generation
• Thermal Maillard reactions associated with flavour generation

  • Strecker degradation
  • Oxidative decarboxylation
  • Deamination
  • Formation of flavour compounds
• Strecker degradation


  • Alpha-amino acids breakdown at high temperatures or with the help of catalysts in the presence of a carbonyl group
  • Carbonyl group from a sugar molecule binds to the amino group of the amino acid
  • Reaction is key for Maillard browning
  • Reaction results in the formation of a Schiff base and water as it is a condensation reaction
  • Next, oxidative decarboxylation and deamination takes place
  • Schiff base undergoes and forms aldehydes (with one less carbon atom than the original alpha-amino acid) and alpha-ketosamines
  • These two molecules are what give flavour
• Psychology and physiology are crucial in sensory testing because they influence how people perceive taste, aroma, and other sensory cues
• Psychological factors


  Cognitive biases and expectations can affect how people interpret sensory information
• Physiological factors


  Genetics, age, and health can influence taste and smell perception
• Controlling for both psychological and physiological factors is essential to ensure reliable results in sensory evaluation
• Key variables to consider when designing and conducting a sensory test


  • The food (freshness, preparation method, portion size, etc.)
  • The people (selection criteria, training, number of participants, etc.)
  • The testing environment (lighting, temperature, noise level, etc.)
  • Test methods used (triangle test, QDA, etc.)
• Triangle Test


  Participants identify the odd sample out of three
• QDA (Quantitative Descriptive Analysis)


  Trained panelists describe sensory attributes of a product
• Sensory biases


  • Psychological factors (e.g., expectations, prior experiences)
  • Physiological factors (e.g., genetics, age, health)
  • Cultural factors (e.g., familiarity with flavors)
• Methods to mitigate sensory bias

  • Standardize testing procedures
  • Blind testing (participants don't know what they are tasting)
  • Balanced presentation of samples
  • Train panelists to recognize and minimize bias
• Thematic Analysis


  Identifying themes and patterns in qualitative data from sensory evaluation
• Coding


  Assigning labels to categorize and organize data for analysis
• Sensory evaluation provides valuable information about a product's perceived sensory characteristics, influences economic decisions based on consumer preferences, helps ensure product quality and consistency, and complements instrumental analysis for a holistic understanding
• Stages in designing sensory experiments

  1. Formulate objectives

  2. Decide on data collection

  3. Analyze and utilize data
• Types of sensory tests

  • Discrimination (determines if a difference exists between products)
  • Description (describes and measures sensory attributes of products)
  • Preference (identifies consumer liking or acceptability of products)
• Quality Index Method (QIM)


  Assigns scores based on appearance, firmness, odor, etc. to evaluate fish quality
• Sensory assessment uses sight, smell, taste, touch, and hearing to evaluate fish quality
• Freshness of fish is determined by appearance (bright, shiny skin), odor (mild, seaweedy), flavor (neutral or slightly sweet), and texture (firm, elastic)
• Sensory evaluation plays a crucial role in the food industry, ensuring product quality and consistency, leading to consumer satisfaction and business success, and providing insights into consumer preferences for product development and marketing strategies
• Instrumental analysis is a valuable tool that guides numerous economic decisions in the food industry, helping maintain quality, optimize costs, develop successful products, comply with regulations, and inform pricing strategies
• The effectiveness of instrumental analysis is often amplified when combined with sensory evaluation for a comprehensive approach
• The first step is to identify the problem, which can be done by asking questions such as "What are we trying to achieve?" or "Why do we need this system?