Class notes
Summary Advanced biochemical anlysis of foods
- Course
- Institution
This document consists of a summary of all the lectures given in the course.
[Show more]
1 review
By: kiriakoctugpsd • 1 year ago
Seller
Followsadhanachangoer
Reviews received
Content preview
ABAF lecture notesInhoud
Week 1..................................................................................................................................................... 2
Intro lecture – Peter Wieringa 15-03-2021 ......................................................................................... 2
Separation by gas and liquid chromatography – Wouter de Bruijn 16-03-2021 ................................ 4
Mass spectrometry – Wouter de Bruijn 18-03-2021 .......................................................................... 8
Week 2................................................................................................................................................... 15
QAQC – Peter Wieringa 22-03-2021................................................................................................. 15
Carbohydrates – Henk Schols 23-3-2021 .......................................................................................... 19
Proteins – Peter Wieringa 25-03-2021 .............................................................................................. 24
Week 3................................................................................................................................................... 29
Bio-functional carbohydrates – Henk Schols 29-03-2021 ................................................................. 29
Bioassays: Introduction and general principles – Nico van den Brink 30-03-3021 ........................... 35
Bioassays: Food safety – Nico van den Brink 01-04-3021 ................................................................. 37
Week 4................................................................................................................................................... 39
Food Fraud and Authentication – Saskia van Ruth 06-04-2021 ........................................................ 39
1
,Week 1
Intro lecture – Peter Wieringa 15-03-2021
Learning outcomes:
• Interpret results from analytical methods
• Identify errors in results from analytical methods
• Explain which analytical techniques are typically applied in different fields
• Describe the basic principles of analytical methods
• Select the analytical techniques needed to study different compounds
• Steps in analysis: Sampling (may cause some variation), sample preparation, detection and
quantification.
• Reasons for food analysis are product composition analysis, for labelling, quality assurance
and control, for research and development.
• Food safety, fraud and defence: Key marker compounds and bioassays. Also, report and
recalls.
• You cannot measure all the produced products; therefore you need to take samples.
• How to prevent error in analysis:
- What analysis methods are currently used
- How do these methods work?
- How reliable are those measurements? Confidence and how to increase confidence.
- How to draw strong conclusions.
• In this course: Product authenticity and toxicology.
• Describing the quality of the analysis: Precision and accuracy: Accuracy describes the extent
of over or underestimation of the results.
• Sampling protocols: Product → Analysis → Signal → Amount
- Random: ensure that every item in the population of the food being sampled has an
equal chance of being collected and incorporated into the sample to be analysed
- Stratified: random sampling in pre-defined subpopulations
- Selective sampling: Only in part of the subpopulations
- Convenience sampling: Only accessible etc
• Understanding levels of variation:
- Determine variation in the population: Selection of representative products to sample
- Reduce variation in each product by: Taking representative samples and increasing
sample size.
- Determine variation in analysis: Analyse samples in replicate (multiple times)
2
,• Challenges: Compound of interest:
• The detection of very small amount of analytes is difficult, the sample preparation needs to
concentrate the analyte, and remove other compounds.
• Examples of sample preparation, with precision:
- Extraction
- Precipitation
- Filtration
- Centrifugation
- Drying
- Heating
- Chemical conversion
• Detection: You don’t determine ‘proteins’, but you determine absorbance, RI, m/z, weights.
• Basics of detection method calibration:
Trick: Always re-calculate the concentration of your standards based on your calibration line.
• Other components in the sample can change the detector response. Especially in MS
presence of other compounds (co-elution) can lead to a lower signal intensity of your
analyte.
• Statistics: The normal distribution Comparing two samples:
• Comparing results: For duplicate measurements of two samples, the average values for the
two samples should at a distance of 12σ to be significantly different.
3
, • Testing for compound presence: Screening:
Identification of positive (Suspicious) samples – low precision. False positives are OK → will
be verified later in confirmation analysis. False negatives to be avoided.
• Method validation: Stronger conclusion and improved confidence in results by understanding
of the method principles, identifying sources of variation and tools to validate the method →
Schemes in the slide and knowledge clip Intro4.
Separation by gas and liquid chromatography – Wouter de Bruijn 16-03-2021
• General principles of chromatography: Detecting individual compounds after separation
• Goal: Separation of a mixture to enable analysis of individual compounds
• Method: Competition of compounds being adsorbed on the stationary phase or being
carried by the mobile phase.
• Methods: Liquid chromatography: Mobile phase which is liquid. Gas chromatography: Mobile
phase which is gas. Compounds with low affinity to the stationary phase elute early.
• Method selection and their detectors:
• Polarity intermezzo: More Acid groups/-OH/-NH2/Ether per molar mass is more polar.
4
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller sadhanachangoer. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $6.58. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
79650 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now