This experiment aims to determine the presence of different polysaccharides in different food types.
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This experiment seeks to determine of the presence of beta-glucan and how its contents differs in several glucose polymers. The investigation also explores the role of beta lichenase in determining the beta-glucan content.
The experiment determines the significance of standard procedures in determining the quantity of individual food constituents. Therefore, the experiment’s overall aim is to investigate some of the analytical methods used for plant-based food polysaccharides.
Procedure 1: Determination of amylose in potato starch
Approximately 20 mg of potato starch sample was weighed into a 10 mL glass tube. 20 mg of three calibration standards were also weighed into separate 10 mL (0% amylose/100%, 25% amylose/75%, 50% amylose/50% amylopectin). Accurately, 2 mL of 2 M of NaOH was added to the samples and the standards. The tubes were capped and heated in a 95 degrees water bath while constantly shaking for 20 to 30 minutes. The samples were cooled, and 4 mL of deionized water was added with vortex mixing. 0.1 mL of each solution was taken and put into uncapped glass tubes, and 5 mL of 5% trichloroacetic acid (TCA) was added to each glass tube. 0.05 mL of I2-KI solution was added (0.13% I2 and 0.3% KI). The mixtures were incubated at room temperatures for 30 minutes. The absorbance of the samples was read at 620 nm against a water blank. The percentage amylose in the content was then calculated.
Procedure 2: Determination of β-glucan in cereals
The cereal samples were ground separately into flour using a pestle and mortar (approximately 2.0 g each). 100 mg of each sample was weighed into 15 mL centrifuge tubes. 0.2 mL of 50% ethanol was added to the tubes and swirled to mix. 4.0 mL of sodium phosphate buffer (20 mM, pH 4.0) was added and vortexed gently, and placed in a water bath for 60 seconds. The tube was vortexed moderately and was returned to the boiling water for another 2 minutes. The tube was removed out of the water bath and vortexed again. The tube was placed in a 50 degrees Celsius water bath to equilibrate. 0.4 mL of lichenase was added to the contents in the tube and swirled to mix. The tube was covered with parafilm and incubated at 50 degrees Celsius for 30 minutes. The contents of the tube were mixed 2-3 times during the incubation period. 5.0 mL of sodium acetate buffer (200mM, pH 4.0) was then vortexed and incubated at room temperatures for 5 minutes. The parafilm was removed, and the tube was centrifuged at 3,000 rpm for 5 minutes. Two 0.1 mL aliquots of each sample were transferred to two clean test tubes. 0.1 mL of β-glucosidase was added to one of the tubes 0.1 ml of sodium acetate was added to another tube to act as a control. The tubes were then incubated at 50 degrees Celsius for 10 minutes. A glucose standard curve was prepared by adding 0, 0.05, 0.1, 0.15, and 0.2 mL glucose to five tubes. The contents were made to volume (0.2 mL) with 50 mM sodium acetate (pH 4.0). 3.0 mL of GOPOD reagent was added to all the tubes and incubated at 50 degrees Celsius for 20 minutes. The absorbance of the samples and the standards was read at 510 nm against a water blank. The β-glucan content of the samples was then calculated.
Method 3: RVA analysis of various starches
Pasting properties of starch.
Polysaccharides are a macro-portion of our food constituents, and their analysis and determination of their contents are helpful (Van Dam et al. 2017). In this experiment, the determination of their presence and their content was the objective. In the first experiment, the determination of amylose in potato starch, the experiment’s result was positive. The absorbance results determined that there was a substantial amount of amylose in potato starch (Lemos et al. 2019). In the second experiment, the absorbance results showed the presence of β-glucan in both oat and barley samples. The β-glucosidase hydrolyses the oligosaccharides to free glucose (Zielke et al. 2018). The results found in this experiment test positive for the presence of glucose. The third experiment is the Rapid Visco Analyzer experiment used to test for starch’s viscoelasticity in various food samples (Balet et al. 2019). The viscosity results in the experiments indicate that there is a presence of polysaccharides in the samples tested.
Balet, S., Guelpa, A., Fox, G. and Manley, M., 2019. Rapid Visco Analyser (RVA) as a Tool for Measuring Starch-Related Physiochemical Properties in Cereals: a Review. Food Analytical Methods, 12(3), pp.1-17.
Lemos, P., Barbosa, L., Ramos, I., Coelho, R. and Druzian, J., 2019. Characterization of amylose and amylopectin fractions separated from potato, banana, corn, and cassava starches. International Journal of Biological Macromolecules, [online] 132, pp.32-42. Web.
Van Dam, J., Van den Broek, L. and Boeriu, C., 2017. Polysaccharides in Human Health Care. Natural Products Communication Journal, [online] 12(6). Web.
Zielke, C., Stradner, A. and Nilsson, L., 2018. Characterization of cereal β-glucan extracts: Conformation and structural aspects. Food Hydrocolloids, 79, pp.218-227.