Effect of amylose/amylopectin ratio and extent of processing on the physical properties of expanded maize starches

Beech, Daniel; Beech, John; Gould, Joanne; Hill, Sandra

Abstract

Low-density expanded starchy products are often desirable, particularly in the snack food industry. Levels of shear and amylose are often deemed crucial factors for expansion. In this study, maize starches containing low (waxy), normal and high levels of amylose were compared after processing. Low shear processing used a popping head (similar to a rice-cake machine), while high shear (~450 kJ kg−1) samples (pellets and directly expanded) were created using twin-screw thermomechanical extrusion. Native starches and ground extruded materials (<106 µm) were popped using the same conditions (230 °C, 4 s, water content 12% wwb). All samples tested created fused aerated cakes, which had little or no remaining crystallinity, except for the directly popped waxy sample, which retained ~17% of its original crystallinity. Water absorbances and solubilities were influenced greatly by the starch source and marginally by the amount of processing. On processing, waxy samples showed increased solubility while those with normal amylose content had greater absorption. The densities of all the popped samples were similar despite marked differences in shear regime history and the major variations in the amylose and amylopectin ratios. These results challenge the expected relationships between shear and different starches’ potential to expand.

Citation

Beech, D., Beech, J., Gould, J., & Hill, S. (2022). Effect of amylose/amylopectin ratio and extent of processing on the physical properties of expanded maize starches. International Journal of Food Science and Technology, 57(4), 2298-2309. https://doi.org/10.1111/ijfs.15581

• Journal Article Type: Article
• Acceptance Date: Jan 15, 2022
• Online Publication Date: Feb 8, 2022
• Publication Date: 2022-04
• Deposit Date: Jan 28, 2022
• Publicly Available Date: Feb 8, 2022
• Journal: International Journal of Food Science and Technology
• Print ISSN: 0950-5423
• Electronic ISSN: 1365-2621
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 57
• Issue: 4
• Pages: 2298-2309
• DOI: https://doi.org/10.1111/ijfs.15581
• Keywords: Industrial and Manufacturing Engineering; Food Science
• Public URL: https://nottingham-repository.worktribe.com/output/7344559
• Publisher URL: https://ifst.onlinelibrary.wiley.com/doi/abs/10.1111/ijfs.15581