Generation and Characterization of Pyrodextrins and Maltodextrins from Pea and Maize Starches
Date
2025-01-06
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ORCID
Type
Thesis
Degree Level
Masters
Abstract
Peas are largely grown for their protein component to produce pea protein concentrate and isolate. After the protein extraction, pea starch is generated as the main co-product. Thus, there is substantial untapped potential in the development of value-added products from pea starch, the leading component in pea grains. The low cost, in combination with the underutilization status of pea starch, fosters research efforts in transforming this polysaccharide into higher-value products, which will allow for increasing growth in this relatively overlooked market. Such development will enable the utilization of the starch in a wider variety of products and provide additional options for valuable health benefits such as increased dietary fiber. Dietary fiber is a high-value food ingredient as it is well documented to have numerous positive effects on health, such as aiding in weight management, glycemic and insulinemic control, and improvement of colon health. One good example of dietary fiber that can be derived from pea starch is pyrodextrin. Similarly, the production of maltodextrin from pea starch will aid in the development of new products because pea-based maltodextrin is expected to have different properties as compared to the more common maize-based maltodextrins. These different properties will not only create new applications for pea starch but also aid in further development of new applications in a large variety of sectors.
For the first study, pea, waxy maize, and normal maize starches were stirred with hydrochloric acid at a pH of 3.0 for 30 min, dewatered, and dried at 40°C to reach a moisture content of 15.0% ± 2.5%. The samples were then heated at 180°C for 1, 2, or 4 h, followed by equilibration under atmospheric conditions and milling with a 0.5-mm sieve. The pea-, waxy maize-, and normal maize-based pyrodextrins had a decrease in amylose content of 35.1% to 1.1%, 2.3% to 0.7%, and 27.7% to 10.8%, respectively. The samples also had an increase in water solubility of 1.1% to 94.1%, 0.2% to 40.7%, and 0.1% to 39.9%, respectively. Additionally, the modification increased the enzymatic resistance of pyrodextrin. The pea-based pyrodextrin had approximately 30% enzymatic digestion resistance, while the normal maize- and waxy maize-based pyrodextrins only had around 10%. Overall, the pea-based pyrodextrin showed greater changes across the tested properties, indicating that pea starch is a better substrate for pyrodextrinization than maize starches.
For the second study, the same pea, waxy maize, and normal maize starches were hydrolyzed using α-amylase with and without ultrasonication to determine if the application of ultrasonication during the enzyme reaction resulted in a greater degree of enzymatic hydrolysis and changes to the physicochemical properties of the derived maltodextrins. Results showed the enzyme activity was minimally impacted by the addition of ultrasonication. The pea-, waxy maize-, and normal maize-based maltodextrins all had minimal change to their molecular-weight distributions with the addition of ultrasonication. However, notable change was observed in the water solubility of pea-based maltodextrins, while the waxy maize- and normal maize-based samples both showed minimal change in water solubility at room temperature. The transmittance of light through the samples in aqueous medium was also affected by ultrasonication. The pea-based and normal maize-based maltodextrins showed a notable increase in the transmittance while minimal change was observed in the waxy maize-based samples. Overall, the ultrasonication during the α-amylase hydrolysis of pea, waxy maize, and normal maize starches led to notable effects on the physicochemical properties of the produced maltodextrins.
The new findings from this thesis research will be useful for the production of pea-based pyrodextrin and maltodextrin that will have diverse applications in the food system. The gained new knowledge and technologies will enable the pulse processing industry to identify new markets for this main component in pulse grains.
Description
Keywords
Pyrodextrin, Maltodextrin, Ultrasonication, Pea starch, Waxy maize starch, Normal maize starch, Molecular structure, Physicochemical property, Enzymatic digestibility
Citation
Degree
Master of Science (M.Sc.)
Department
Food and Bioproduct Sciences
Program
Food Science