Lecture 1 - Introduction Flashcards
Scope of food analysis?
- government/industrial regulations and recommendations
- food safety and quality control
- Research and development
describe role of government/industrial regulations and recommendations
- to ensure wholesomeness and safety of food
- ensure nutritional composition of foods
- enable fiar industrial competitions (authenticity/grade)
- eliminate economic fraud
describe role of food and safety and quality control
- avoid hazardous agents and ensure consumer safety
- avoid economic backlash arising from unsafe constituents
- product consistencyy
- monitoring food during transit through the value chain
- adherence with GMP and HACCP
what is HACCP
Hazard analysis and critical control points
what is GMP
good manufacturing practice
steps in quality management in the industry?
- raw materials
- processing
- final product
roles of research and development
- remain competitive within food industry
- basic research on interactions of food components
- product process development
importance of R&D on food component interactions?
- shelf life and spoilage
- impact of quality and texture of the food with other factors (ie light and O2)
- impacts on nutritional quality
- don’t want production of toxins
composition is defined in terms of…
- atoms
- specific molecules
- types of molecules
- specific substances
- total ash and moisture
what is proximate analysis of foods?
refers to determining the major components of food: moisture, ash (total minerals), lipids, proteins and carbohydrates
what is AOAC
association of official analytical chemistry
describe AOAC’s triangle scheme for diving foods into matrix categories
3 main matrix categories: fat, carb, pro
- nine possible combinations of high, med, and low levels of fat, carb and pro
- general analytical methods used for handling the food depends on which combination the food is (ie different categories should not be analyzed the same way)
the structure of food is determined by
- molecular structure of constituents
- microscopic structure
- macroscopic structure
define the structure of food
the physical form in which food components are packed in the matrix
what are the 4 physicochemical properties?
- rheological properties
- optical properties
- physical firmness
- chemical stability
what is rheology
flow of matter
individuals perceptions of sensory attributes are often…
subjective
factors that may influence individual perception are…
state of mind and body
age
educational background
ambience of the test environment
workflow of food analysis?
- planning stage: what methods? why? how?
- sampling plan: using a batch to represent a whole population
- sample processing/prep: ensure homogeneity of sample (ie crushing sample first)
- analysis and detection
- data and results
define precision
A measure of the ability to reproduce an answer between determinations performed by the same scientist (or group of scientists) using the same equipment and experimental approach
define reproductibility
A measure of the ability to reproduce an answer by scientists using the same experimental approach but in different laboratories using different equipment.
define accuracy
A measure of how close one can actually measure the true value of the parameter being measured, e.g., fat content, or sodium concentration
define simplicity of operation
A measure of the ease with which relatively unskilled workers may carry out the analysis.
define cost
The total cost of the analysis, including the reagents, instrumentation and salary of personnel required to carry it out.
define speed
The time needed to complete the analysis of a single sample or the number of samples that can be analyzed in a given time.
define sensitivity
a measure of the lowest concentration of a component that can be detected by a given procedure
define specificity
a measure of the ability to detect and quantify specific components within a food material, even in the presence of other similar components
define online/offline
some analytical methods are used to measure the properties of a food during processing. Ohters can be used after the sample has been taken from the production line
what influences the type of method used to carry out an analysis?
composition, structure and physical properties of the matrix material surrounding the analyte
3 legally accredited organizations
AOAC: association of official analytical chemists
AOCS: american oil chemists society
AACC: american association of cereal chemists
what is the primary objective of sample selection?
to ensure that the properties of the lab sample are representative of the properties of the population to avoid erroneous results
analytical techniques for acidity and pH?
pH meter
pH indicator strip
analytical techniques for moisture or dry matter
drying
distillation
chemical (karl fisher method)
physical
analytical techniques for total N or crude protein
Kjeldahl method
Dumas Method
analytical techniques for fat?
fat extraction using solvent (soxhlet)
- saponification value
- iodine value
- peroxide value
analytical techniques for carbohydrate?
- polarimetry
- refractometry
- specific gravity methods or desitometry
- chromatography
- chemical methods
analytical techniques for minor compounds?
- spectrophotmetric
- chromatographic
- enzymatic
- fluorometric
- imunological methods
analytical techniques for total ash (minerals)
dry ashing
wet ashing
