Glucose from Starch

Glucose Production:

There are several methods of producing Glucose syrup from starch:

1- Acid conversion method

2- Enzymatic process

3- Carbon free method

First method is the most economic and traditional process, Enzymatic process is the most common one and Carbon free method is the most advanced one which is economic for high capacity processing line.

Depends on the applications, Glucose syrup has verities of DE ranging from around 30 to around 95. Higher DE required for acting as a sweeteners mainly. Glucose syrups can be divided into 4 groups based on the degree of conversion, Low Conversion 20-35 DE, Intermediate Conversion 35-55 DE, High Conversion 55-70 DE and Very High Conversion 70-98 DE.

The following flowchart provides a brief overview to the main Glucose production processes based on Carbon Free method.To see the flowchart, please click here


Glucose Production Process Description:

Here is a brief description of Glucose syrup production based on carbon free method. For all other methods which are more economic and applicable to small and medium processing line, please call our process engineers:

1- Slurry preparation

Starch slurry is pumped into the slurry preparation tank. By adding water the concentration is adjusted to about 18°-21bé, and then pH value is adjusted to about 6.0, finally liquefying amylase is added.

2- Liquefaction

The aim of the liquefaction process is to convert the starch slurry into liqueur by breaking the starch molecules with enzyme under determined temperature, pressure and reaction time. The prepared starch slurry is pumped into the feeding tank in which it is pre-heated to about 50℃. Then it is pumped into an ejector for cooking. After ejection its temperature is controlled at 110℃for 5-10 minutes, and then it is cooled down to 100℃in a very short time and insulated for about 2 hours. After killing amylase it is cooled down again to 58-60℃in a very short time.

3- Saccharification

In this step, Glucoamylase enzyme or another type of enzyme is used to complete the breakdown of starch into dextrose. The amylase is added immediately and the slurry is pumped into Saccharification tank. It takes about 40 hours for Saccharification. When the Saccharification liquid reaches the required DE value, it is heated to 70℃ immediately.

4- Preliminary and Membrane filtration

Before entering to MEMBERANE SYSTEM, glucose is filtered from slags created during liquefaction and scarification process. Saccharified solution containing several organic compounds (for example: proteins, fatty substances, not liquefied starch, long chain polysaccharides, fatty acids, protein and fiber). The traditional method for removing these impurities was using activated carbon and diatomaceous earth and filtrating them using filter press and rotary vacuum filter. But new technology is using MEMERANE FILTERATION. This system has a lot of advantages including the following but not limited to:

a) Better quality of starch sugar

b) Very low weigh in comparison with other systems and can significantly decrease building load

c) Flexibility for layout design at it can be placed wherever even on the floor.

d) High efficiency

e) As it works in a closed system, the bacteria growth is very low in comparison with other methods

f) Reduces number of labors for operation

5- Demineralization ( Ion Exchanging)

When the liquid is cooled down to below 50℃, it is fed to the ion exchange system. Ion exchangers are cation and anion ion-exchanger.

6- Evaporation

The refined liquid from ion exchanging section then comes to the evaporator to be concentrated to the required value. Three main common evaporators are used for glucose concentration to required DE, falling film, plate and MVR evaporators; each one has its own advantages and disadvantages.