Carbohydrates lecture 2 Flashcards
Ring Formation:
Ring forms when a c4 or 5 atom attacks a carbonyl group producing a hemiacetal ring. The hemi-acetal ring then reacts with another hydroxy group and forms a full acetal glycosidic ring which makes up polymeric structures.
Number of possible dissacharides:
Different dissacharides are made possible by the various different bond linkages made between glucose molecules, ex: alpha 1,4 linkages and beta 1,6 linkages.
Heterogenous dissaccharides:
Dissaccharides made between two different types of glucose molecule units Ex: glucose bonded to fructose.
Malto oligomers:
Units of glucose arranged in three or more subunits that have the same glycosidic bonds as maltose. The terminal group is a reducing sugar which allows malto oligmers to use it’s carbonyl group to react with other compounds to engage in browning reactions, more glycosidic bonding etc.
cyclodextrins
These are compounds which contain dextrins sugars chair conformations bonded in a cyclic form to contain a hydrophobic interior where hydrophobic molecules can be sucked into to bond Ex: how febreeze freshener sucks out all the dirt molecules in the air.
Polydextrose
glucose molecules bind together in a process called reversion which occurs at a low ph and low moisture content. A wide variety of glycosidic bonds connect the glucose molecule and the ending group is a hydrogenated form of glucose (sorbitol) which can’t participate in any reaction. It has a low volume, viscosity, high molecular weight molecule, is broadly spread out and is resistant to enzymatic degradation
Fructans and Inulin
Fructans are made of chains of oligo and polysaccaride glucose units with a terminal end that does not react any further. The extent of polymerization varies upon the source it comes from and they are all bonded like sucrose units. Inulins contain higher degree of polymerization (more glucose units), are the major source of carbohydrate energy for the roots of plants and are hydrolyzable under a variety of cond.
Rattinose and starchyo
Found in beans and contains a 1,6 galactopyranose and enzymes exist in beans to break it down releasing gas in the stomach before enzymes in gut microbiota need to
Hydrolysis of glycocidic bonds and depolymerization of starch
Acid or enzymes break glycocidic bonds into individual glucose units. Acid hydrolysis is used to thin starch or reduce it’s molecular weight before it is broken down in by enzymes into individual glucose units. It can also be done by acid hyrolysis or enzymatic hydrolysis individually.
Startch hydrolysis
Amylose +Amylopectin is broken down into acid thinned starch, which is then broken down into maltodextrins and then corn syrup and then glucose syrup which contains glucose and glucooligemers
DE Value
Refers to the average molecular weight of a starch molecule and is calculated by using the formula: total molecular weight divided by the number of molecules. It is inversly proportional to the molecular weigh and is a good indicatior of how many sugar molecules are present in the soluti
oxidation of carbonyl group
this is a reaction meant to show the amount of sugar molecules present in a solution hence it’s DE value. There are benidict reagents which oxidize carbonyl groups of aldose molecules indicating the presence of aldoses
Feheling reagent and tolling-general reducing sugars
tollen silver mirror test:
reducing sugar that reacts with a silver diamide to produce a silver color at the bottom of the solution indicating the presence of silver color indicating the presence of reducing sugars
lactones
D gluconate»_space;>Glucolactone: conversion of a glucose to a ring structured lactone through the reaction between a straight chain carbonyl group it’s OH group. The enzyme is glucose oxidase which is a good indicator of the number of glucose molecules present in a solution.
Uses for gluconolactone
Hydrolysed to lower the pH in a homogenous manner providing a smooth texture to gels especially with the release of ions from calcium salt, produce co2, and coagulate proteins.
