Low acyl gel strength testing method
1. Instruments: magnetic stirrer, Brook field texture analyzer, 50*30mm aluminum box or other equivalent gel testing equipment, incubator.Measurement conditions: a) set the magnetic stirrer to 80°C, speed to 380r/min. b) Probe model: Stainless steel probe with a bottom area of 1cm². c) Probe speed: 0.1mm/s. d) Measuring temperature: 20 ℃ (room temperature).
2. Analysis step: prepare a 0.5% gellan gum gel.
a) prepare 120g (accurate to 0.01g) of distilled water,draw into a 250 mL Erlenmeyer flask equipped with a magnetic head;
b) Take 0.6g gellan sample with clean and dry weighing paper (accurate to 0.001g), and at the same time, turn on the stirring and slowly and evenly add the above sample into an Erlenmeyer flask containing 120g distilled water to disperse and dissolve the sample. Weigh and record the gross weight of the Erlenmeyer flask;
c) Place the above-mentioned Erlenmeyer flask on a magnetic stirrer to heat and dissolve. When the temperature reaches 80°C, start stirring for 10 minutes.
d) Take 2 mL of 2.7% calcium chloride solution, add the solution into the Erlenmeyer flask of the magnetic stirrer drop by drop , and continue stirring for 1 minute.
e) Weigh the gross weight of Erlenmeyer flask, record the number of differences, use a pipette to measure a certain amount of boiling distilled water to add the evaporated water to the original weight, place the Erlenmeyer flask on a magnetic stirrer and stir for 1 minute, then quickly pour them into the 2 aluminum boxes(50g for each box)then place it in the turnover box for 30 minutes to gel, place the aluminum box with a lid in a 20°C constant temperature box for 20 hours to be tested.
4. Measurement: Place the 0.5% gellan gum gel on the Brookfield texture analyser stage, measure under the above measurement conditions, place the probe in the center of the weighing dish for measurement, and the instrument reading will be the gel strength value . Two results were measured in parallel and the average value was taken.
High acyl gel strength testing method
1. Instruments: magnetic stirrer, Brook field texture analyzer, 70*35mm aluminum box or other equivalent gel testing equipment, incubator.
2. Measurement conditions: a) set the magnetic stirrer to 90°C, speed to 600r/min. b) Probe model: ΓΈ6mm gel probe. c) Probe speed: 0.1mm/s. d) Measuring temperature: 25 ℃ (room temperature).
3. Analysis step: prepare a 1% gellan gum gel.
a) prepare 120g (accurate to 0.01g) of distilled water,draw into a 250 mL Erlenmeyer flask equipped with a magnetic head;
b) Take 1.2g gellan sample with clean and dry weighing paper (accurate to 0.001g), and at the same time, turn on the stirring and slowly and evenly add the above sample into an Erlenmeyer flask containing 120g distilled water to disperse and dissolve the sample. Weigh and record the gross weight of the Erlenmeyer flask;
c) Preheat the above-mentioned Erlenmeyer flask, and then place it on a magnetic stirrer to heat and dissolve. When the temperature reaches 90°C, start stirring for 20 minutes until it is completely dissolved((In this process, no muddy bottom or sample overflows allowed)).
d) Take 2 mL of 2.7% calcium chloride solution, add the solution into the Erlenmeyer flask of the magnetic stirrer drop by drop , and continue stirring for 1 minute.
e) Weigh the gross weight of Erlenmeyer flask, record the number of differences, use a pipette to measure a certain amount of boiling distilled water to add the evaporated water to the original weight, place the Erlenmeyer flask on a magnetic stirrer and stir for 1 minute, then quickly pour it into an aluminum box,then place it in the turnover box for 30 minutes to gel, place the aluminum box with a lid in a 20°C constant temperature box for 20 hours to be tested.
4. Measurement: Place the 1% gellan gum gel on the Brookfield texture analyser stage, measure under the above measurement conditions, place the probe in the center of the weighing dish for measurement, and the instrument reading divided by 0.2826 to get the gel strength value . Two results were measured in parallel and the average value was taken.
High acyl viscosity detection method
1. Instrument: viscometer (S62 rotor, 1.5 revolutions)2. The total change is calculated as 0.045% HG, 0.03% NaCl, 4% sucrose
3. Operation steps: Weigh 0.18 g sample (accurate to 0.001 g) Placed in a 500mL beaker containing 400g of distilled water, add 600uL of 20% NaCl, and then add 16g of sucrose, place it on an electric stove to boil and stir with a glass rod. After the sample is completely dissolved, cool down to the room temperature (25℃). )check the reading after 5 minutes to get the viscosity value.
Low Acyl Gellan Gum Transparency rate test
1. Instruments
Magnetic stirrer, 722 spectrophotometer or equivalent instruments.
2. Determination conditions:
a) wavelength: 497nm。
b) cuvette: 1*1cm
3. Analytical procedure:Preparation of a gel containing 0.5% of the sample solution
a)measure 120ml distilled water in 250ml triangular bottle with a magnetic head;
b) with a clean, dry paper accurately weighing 0.6g samples(accurate to 0.001g), while stirring and evenly pour the samples into the 120ml distilled water flask containing. The samples was dispersed and dissolved, then weighing flask total weight and recording.
c)place above flask containing on a 80 ℃ magnetic stirrer heating for 30 mimutes, then stir(the temperature was raised to 80 ℃ start time), add 2.7% calcium chloride 2ml, stirring was continued uniformly on a magnetic stirrer, remove the triangle bottle with distilled water and add to the original weight of water evaporated, stirring evenly into the 1*1cm cuvette, then retain the cuvette to a 20℃ incubator.
4.Determine and reading
Remove cuvette, using 722 spectrophotometer to determine the gel transmittance with distilled water as a control at 497nm. Parallel determination of three samples averaged.
