AGEN2002 Lecture Notes - Lecture 3: Epb41, Dietary Fiber, Food Safety
15 May 2018
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3. Analysis of food for safety and quality
Ø Quality attributes of fresh produce include visual (appearance, colour), textural, flavour
(taste, aroma) and nutritional characteristics
o Attempt to be objective but are very subjectively perceived
Ø Fresh produce management
o Manage quality, functionality, shelf-life & safety to meet consumer demands
Ø Assessment of quality attributes takes several approaches
o Measurement of underlying physicochemical properties
o Measurement of sensory manifestation
o Evaluation of consumer perception
Measuring quality & safety
Reliable and accurate across a wide range of sample types, not subject to inter-laboratory/operator
variation
Typical analyses of foods
• Energy value (protein 4.1 cal/g, fat 8.8 cal/g, carbohydrate 4.1 cal/g)
• Moisture
• Protein (measuring N, some amino acid analysis)
o Since measuring N is debatable, trying to find other ways to measure eg. hydrolysing
• Fats (total, saturated, unsaturated)
• Ash
• Carbohydrate (Sugars, dietary fibre) – measured by total- (protein+fat+water+ash+alcohol)
• Salt (sodium)
Analytical methods
Physical analysis & chemical analysis
• Measure specific properties or components (e.g. sugar, protein)
• Well defined, precise, accurate
• Usually difficult to relate properties of specific constituents to functionality of the whole
Functional tests
• Practical & relevant to apps
• Measure collective properties of complex materials
Sensory methods
• Color, taste, odour, visual appearance, size, shape, texture, firmness
• E.g. color & image analyzers, texture analysers, electronic noses; sensory panels
Document Summary
Analysis of food for safety and quality. Quality attributes of fresh produce include visual (appearance, colour), textural, flavour (taste, aroma) and nutritional characteristics: attempt to be objective but are very subjectively perceived. Fresh produce management: manage quality, functionality, shelf-life & safety to meet consumer demands. Assessment of quality attributes takes several approaches: measurement of underlying physicochemical properties, measurement of sensory manifestation, evaluation of consumer perception. Reliable and accurate across a wide range of sample types, not subject to inter-laboratory/operator variation. Physical analysis & chemical analysis: measure specific properties or components (e. g. sugar, protein, well defined, precise, accurate, usually difficult to relate properties of specific constituents to functionality of the whole. Functional tests: practical & relevant to apps, measure collective properties of complex materials. Sensory methods: color, taste, odour, visual appearance, size, shape, texture, firmness, e. g. color & image analyzers, texture analysers, electronic noses; sensory panels, or subjective: survey to determine consumer acceptability.
