isomerization and dextrinization s
TRANSCRIPT
ISOMERIZATION AND DEXTRINIZATION
ISOMERIZATION
Isomers : same molecular formula but different configuration/structure
In carbohydrate chemistry
Glucose isomerase (D-glucose ketoisomerase)
HIGH FRUCTOSE CORN SYRUPS
Source : Applexion® Process for the Production of HFS 55 from Starch, Novasep
GLUCOSE ISOMERASE (GI)
D-Glucose/xylose isomerase : most important industrial enzyme
The production of HFCS by using glucose isomerase was developed first in Japan and later in the United States.
This isomerase also has capability to convert xylose into xylulose , in vivo . This property is utilized in bioethanol formation(as xylose accumulation forms a metabolic block in ethanol formation)
HFCS, an equilibrium mixture of glucose and fructose (1:1) is 1.3 times sweeter than sucrose and 1.7 times sweeter than glucose
High fructose corn syrup is composed of either 42 percent or 55 percent fructose, with the remaining sugars being primarily glucose and higher sugars.
Major Use of HFCS :
In food and beverage industry : AS SWEETNER (Replacing sucrose)
GIS IN MARKET
Brand Name Producer MO System
Sweetzyme Novo-Nordisk Bacillus coagulans suspension
Swetase Nagase Streptomyces phaeochromogenes
suspension
Sweetzyme T Novo-Nordisk S. murinus Bacillus coagulans
Whole cell immobilization
Spezyme Genencor International
S. Rubiginosus Cell freeimmobilization
IMMOBILIZED ENZYME SYSTEMS– MORE EFFICIENT
DEXTRINIZATION
Browning Reaction in Food material :
Reasons :
1. Caramelization [ at High Temp, sugar/starch breakdown]
2. Dextrinization [Starch in Dry conditions]
3. Enzymatic Browning [at low/moderate temp]
4. Sugar-Amine Browning [usually at cooking temp]
DEXTRINS
Dextrins : carbohydrate intermediates between sugar and starch , produced by enzymatic or thermal degradation of starch
Oligomers (-glucose-)n
Amorphous Yellow or white powder
Partially water soluble
Low viscosity (compared to starch)
DE*(degree of hydrolysis on dextrose equivalency) =< 20
*DE (starch)= 0 , DE(dextrose)=100, DE(Corn syrup)=20-99.4
DEXTRINIZATION-PROCESS
Not fully understood
Apparently 3 steps*
1. Hydrolysis (acidic) – α (1-4) and α(1-6) glycosidic bonds (controlled hydrolysis using endo amylases)
2. Transglucosidation
3. Repolymerization
Endo-amylases and Debranching enzymes (isoamylase ,pullulanase and amyolpullulanase) are used.
*Source : Modified Starches: Properties and Uses", O. B. Wurzburg, CRC Press Inc., 1987.
DEXTRINS
Malto-dextrins (Enzymatic)
Pyro-dextrins (Thermal) – Non food applications
Cyclo-dextrins : closed ring oligosaccharide(6,7 or 8 residue)(Intramolecular transglycosylation)
3 types of Dextrins in Market
1. British gum
2. White Dextrin
3. Yellow Dextrin
COMPARATIVE ACCOUNT
Property White Dextrin Yellow Dextrin British Gum
Hydrolysis - - Low (higher pH)
Transglucosidation - higher -
Repolymerization - Very high -
Temperature 80-110 C 150-170 C High temp
Water solubility poor high Poor
COMMERCIAL PRODUCTS
SEBAmyl XCP ( alpha amylase) – Advanced Enzymes (Grain Processing and bakery)
SEBAmyl MTL (alpha amylase) - Advanced Enzymes (Malting and Brewing)
SEBStar MTL (alpha amylase) (malting)
APPLICATIONS OF DEXTRINS
Thickener in Sauces and Soups
Gel Former in Puddings
Suspension Stabilizer
Bodying agent in Baking
adhesive industry AND the paper industry,
the pharmaceutical industry(cyclo-dextrins in controlled drug release )
the food industry, and the textile industry.
Rocket Propelent Binder (Nitropulse Ltd.)
THANK YOU!