STARCH & GLUCOSE SYRUP

Starch a linear fraction amylose & a branched fraction amylopectin.
Most starches contain about 20-39 % amylose
Normal starch contain 70-80% amylopectin while waxy starch contains almost 100 % amylopection
Physical Quality of Starch
Size Distribution
Determines its swelling functionality with granules
Solubility
Starch is not soluble in water
Viscosity
High gelatinized temperatures, high viscosity
Taste
Critical for dairy products, e.g. yogurt
Color
Chemical Quality of Starch
Gelatinization
With higher temperatures granules begins to swell and loses maltese crosses (60-70 oC)
Birefringence
The loss of birefringence determine gelatinization temperature
Starch paste
Viscous mixture of gelatinized starch and liquid
Retrogradation
Crystallization of starch chains in gel
Microbiological Quality of Starch
α-amylases
active at the high temperatures of gelatinization (100-110°C) and liquefaction (80-90°C) to economize processes
therefore there has been a need for more thermophilic and thermostable α-amylases.
Thermostable enzymes from thermophilic organisms
Bacillus, Actinomycetes, Thermomonospora
Physical and Chemical Requirements of Glucose Syrup
Dextrose equivalent
Degree of hydrolysis of the starch, the range of 20 to 75 DE.
Degree of polymerisation
Describes the carbohydrate composition of a syrup
Baumè
Describes the density of specific gravity of a syrup
Physical and Chemical Requirements of Glucose Syrup
Color formation
Maillard reactions
Brown colors in the syrups tend to develop during evaporation or during storage (450C-550C)
Caramelization
Bodying agent
Provide sweetness and mouthfeel
Foam development and stabilization
Low DE products better for emulsion stabilization than high DE products
Physical and Chemical Requirements of Glucose Syrup
Glaze Formation
Low DE glucose for glazing
Used on baked foods to improve their appearance and give some surface protection.
Humectancy
Osmotic pressure and water activity
Glucose syrups
self-preserving, prevent microbial growth
high dissolved solids content in the syrups, binding all the free water
high osmotic pressure and low water activity
Physical and Chemical Requirements of Glucose Syrup
Refractive index
RI increases as the solid content of the syrup increases
RI decreases as the DE of the syrup increases at the same solid content
RI decreases as the temperature of the syrup increases at the same solid content
Specific rotation
Affect the optical and specific rotation of a syrup
Corn
Starch Production
Maize Receipt Quality analysis
Storage
Cleaning Broken maize/debris to animal feed
Steeping Corn steep liquor-fermentation
Coarse milling
Degermination Germ oil extraction
Second milling
Degermination
Fine milling
Fibre seperation Animal feed
Desanding
Gluten seperation Animal feed/fermentation
Starch Refining
Maize Starch Glucose syrups
Corn Starch Production
Maize receipt
üBy a wet milling process, because of maize high oil content
Maize delivery, storage and cleaning
Maize sieves to remove any larger contaminants
Grain is pneumatically transferred to a series of vibratory sieves and winnowing tower to remove both light and heavy contaminations. Broken and damaged nibs removed at this stage
Clean maize nibs are then pneumatically transferred to holding silos
Corn Starch Production
Steeping
Softens the grain to allow milling, moisture content to the optimum for milling
Maize is soaked for 30-50 hours in stainless steel tanks holding at 45-600C using a counter current process
Very important for the quality of starch
Degermination
First stage of the separation process
Release the germ from the endosperm
Germ can be separated from starch, fibre and protein components by its low specific gravity
Corn Starch Production
Fine milling
Produces a finely ground mixture of starch, gluten and fibre
Maximum size reduction of the protein and starch
Fibre fraction is sieved out using multistage bow sieves
Gluten separation
To separate starch from gluten continuous high speed centrifuge is used.
Starch refining
Starch is washed to remove any remaining fibre, gluten and solubles.
End product (starch stream) has 40% dry solids and protein contents less than 0.15%.
Glucose
Syrup Production
Starch Slurry
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