Unit 4-5 Flashcards
How can we plan to synthesize a flavor compound:
- retrosynthesis
- reverse engineering
- disconnection approach
Target molecule:
The molecule to be synthesized
An imaginary bond breaking corresponding to the reverse of a real reaction:
disconnection
Functional group interconversion (FGI):
The process of interconverting one functional into another during retrosynthetic analysis
The process of breaking down a target molecule into available starting materials by disconnection or FGI:
Synthesis backwards
A double line arrow used to indicate the reverse of a synthetic reaction:
retrosynthetic arrow
What is a synthon:
an idelised fragment (usually a cation or anion) resulting from a disconnection
A real chemical compound (reagent) carrying out the function of a synthon:
synthetic equivalent
__________________ is breaking (disconnecting) a target molecule (a molecule we want to synthesize in the lab) on the paper into 2 simpler fragments in such way that they can be reconnected by a known chemical transformation
retrosynthesis
T or F: Heat causes the formation of heterocyclic compounds
T
The overall flavor of foods results not only from carbohydrates, lipids, alcohols, phenols and carbonyl compounds, but also from the various _______________
heterocyclic compounds
T or F: Heterocyclic compounds are present in flavors in such minute traces that before the advent of gas-liquid chromatography (GC), specially in combination with mass spectrometry (GC-MS), they were impossible to detect
T
Although heterocyclic compounds are present only in minute amounts in foods, they constitute the most important character impact compounds (top notes) because of their ___________________
low threshold values
T or F: almost half of the six thousand flavor compounds identified till now, are heterocyclic in nature
T
Many N- and S- containing heterocyclic compounds have been identified in the aroma fraction of foods. In roasted products such as coffee and heat-treated foods (baked bread or fried meat). These heterocyclic compounds are formed from reducing sugars and amino acids by the _______________
Maillard reaction
T or F: numerous furan and pyran derivatives, many of which originate from heat treatment of carbohydrates, largely determine the odor of _________________
processed food
T or F; 2,5-dimethyl-4-hydroxy-2H-furan -3-one and maltol are used in fairly large quantities
T
Furans are mainly associated with ______________________ notes
- caramel-like
- sweet
- fruity
- nutty
- meaty
- burnt
Furans are formed in food by:
*they are almost present in all food aromas and essential oils
thermal degradation of cabohydrates and by the Maillard reaction
Maltol is used in aroma compositions with a ______________ and as a taste intensifier in fruit flavors, particularly in strawberry flavor compositions
caramel note
Thiophenes can significantly contribute to the sensory properties of foods, but they are not as numerous as __________
furans
of the 26 sulfur containing compounds identified in pressure-cooked lean ground beef ___ were thiophenes
20
