NATURAL ORGANIC SUBSTANCES IN FOOD
Learning outcomes of the course unit
At the end of the course the student is expected to be able to:
1) Know which natural organic substances are present in food, how they are analyzed, and what are their properties (Knowledge and understanding).
2) Evaluate the health, toxicological and sensorial properties of natural organic substances contained in food (Applying knowledge and understanding).
3) Communicate in a scientifically correct manner the health, toxicological and sensory properties of natural organic substances contained in food, even to a non-expert public (Communication skills).
4) Evaluate the properties of a food, according to the natural organic substances contained in it (Making judgments)
5) Consult texts with a high technical-scientific content in order to formulate judgments of merit on the properties of natural organic substances in food (Learning skills).
the aim of the course is to teach the students how to approach the problem of the presence of the natural
substances in foods, in particular: how to extract, analyse and characterise the
natural products in food and how to find the scientific demonstrations of their
eventual biological activity, specially in relation to health claims, toxicity and
No official pre-requisite is requested. In order to proficially attend the course, a good knowledge of basic organic and food chemistry is srongly suggested.
Course contents summary
The course is divided into several chapters that will deal with the mechanisms of secondary metabolism that lead to the formation of natural substances in foods, that will be discussed and elucidated through lectures. Additionally, as an integral part of the course, four laboratory experiences will be carried out, allowing students to experience first-hand the extraction and the characterization techniques for natural substances in food.
The course is composed of several parts:
Part 1- Secondary metabolism: biosynthetic pathways and principal mechanisms of
reaction ( alkylation, rearrangements, aldol and Claisen reactions, Schiff's base
formation, transamination, decarboxylation, ox-redox reactions, oxydative coupling
of phenols, glycosylation,etc.). Methods for studying the biosynthesis.
Part 2- The acetate pathway: fatty acids and polyketides. Unsaturated fatty acids
(essential fatty acids). Aromatic polyketides, phenols.
Part 3- The Shikimate pathway: aromatic amino acids, cinnamic acids, lignanes,
coumarines, flavonoids, isoflavonoids. Biological activity.
Part 4- The mevalonate pathway: terpenes (monoterpenes, iridoids,
sesquiterpenes, diterpenes, sterols, sesterpenes, tetraterpenes, carotenoids).
Part 5- Alkaloids: alkaloids derived from ornithine, lysine, nicotinic acids, tyrosine,
tryptophan, anthranilic acid, histidine. Purinic alkaloids, glycoalkaloids.
Part 6- Mycotoxins (aflatoxins, ochratoxin, patulin, trichothecenes, zearalenone):
biogenesis, toxicity, methods of extraction and detection
The lecturing part of the course is divided into several chapters:
1) Secondary metabolism. The biosynthetic precursors and the synthetic mechanisms: alkylation reactions, transpositions, aldol and Claisen reactions, formation of Schiff bases, transamination, decarboxylation, redox reaction, oxidative coupling of phenols, glycosylation reactions.
2) The biogenetic pathway of acetate: fatty acids and polyketides. Unsaturated fatty acids (essential acids). Aromatic polyketides, phenols.
3) The shikimate pathway: aromatic amino acids, cinnamic acids, lignans, coumarins, flavonoids, isoflavonoids. Biological activity.
4) The biogenetic pathway of mevalonate, terpenes: monoterpenes, iridoids, seqsuiterpenes, diterpenes, sesterpens, triterpenes, sterols, tetraterpenes, carotenoids.
5) Alkaloids: alkaloids derived from ornithine, from lysine, from nicotinic acid, from tyrosine, from tryptophan, from anthranilic acid, from histidine. purine alkaloids. Glycoalkaloids.
The laboratory experiences will concern:
1) Extraction of eugenol and methylugenol from spices, and their characterization and quantification with GC / MS
2) Discrimination of robusta coffee variety from arabica variety by methylcafestol extraction and NMR analysis
3) Extraction of lycopene from tomato derivatives and its quantification by UV-Vis
4) Extraction of LTP (main allergen) from peaches and its identification by LC / MS
-Paul M. Dewick, Chimica, Biosintesi e Bioattività delle Sostanze Naturali, Ed. Piccin, Padova
-Material provided by the teacher (scientific notes and articles)
1)Paul.M.Devick- Chemistry, biosynthesis and bioactivity of natural substances.Piccin
2) Slides contents and publications
Lectures take place through power point presentations, transparencies and on the blackboard. Discussions of scientific publications and European regulations will also be held in the classroom. The course is completed by four laboratories aimed at the extraction and characterization of organic substances in food.
The lessons are made by using power point presentations, transparencies and black board
demonstrations. Discussion of scientific papers and of the european regulations are also added.
Assessment methods and criteria
The exam is made by a written test containing a series of problems that are proposed to the students' solution.
Participation in the test is possible ONLY after registration through the ESSE3 system. Students not officially registered will not be admitted to take the test. There will be 8 test sessions per year.
The test consists of exercises that cover the whole program, both practical and theoretical, and exercises on laboratory experiences. The time for the test is 3 hours.
During the test the student can withdraw, and in this case the task is not corrected and the result will be recorded in the ESSE3 system as WITHDRAWAL.
The results of the written test will be published on ESSE3 and each student will receive an email with the result.
The test is considered passed and the grade can be officially recorded if the grade of the test is equal to or higher than 18. In case of a grade lower than 18, the test will have to be repeated.
In the event of a grade equal to or greater than 18, the student has two options:
- Accept the vote received, which will then be officially recorded.
- Reject the vote using the option in ESSE3, and repeat the exam. Attention: the refusal must be explicit, the silence-assent rule applies.
All slides and other materials used in class are provided to students at the beginning of the course, via the ESSE3 system.
In the same site, the students will find all the exercises that will be discussed in the classroom exercises, as well as all the written tests of the two previous years, as a further exercise.
The lecturer talks with the students for clarifications and discussions at the end of the lessons, and is also available to provide further clarification in his office, following an e-mail appointment.