Improvement in popcorn popping performance through edible coatings and understanding inherent factors affecting moisture loss
Abstract
Proper moisture content is an essential factor for the final popping performance of microwaveable popcorn. Moisture loss reduces final popcorn quality. Our objectives were to investigate the potential use of edible coatings to retard the moisture loss during storage and microwaving, and to determine the relationship between reduced rate of moisture loss and popping performance. Also, factors governing the moisture loss were investigated. Lipid-based coating material was superior in retarding moisture loss during extended storage and microwaving, compared to carbohydrate and protein-based polymers. Lipid-coated popcorn had lower rate of moisture loss and better overall popping performance compared to uncoated and other coated samples. Genotypic variability among fourteen Indiana-grown popcorn hybrids was analyzed for their moisture retaining capability during extended storage, popping performance, and moisture retention during microwaving. Hybrids exhibited different moisture retentions during extended storage and also during microwaving. Generally, differences in popping performance were observed among these hybrids. The ability of popcorn to pop was dependent on their moisture retention during microwaving. The hybrid with a high rate of moisture loss during microwaving produced a high number of unpopped kernels. The moisture retaining capability during storage had no impact on the poppability. Removal of water from the kernels resulted in decreased flake size and expansion volume. Scanning electron microscopy revealed that pericarp thickness for the kernel crown area was comparably thin. Single-kernel moisture loss analysis showed that the rate of moisture loss per kernel in each hybrid was different. Kernels with more moisture loss during storage had thinner crown pericarp than others within the same hybrid. Differential scanning calorimetry profiles of ground pericarp displayed exothermal events. Hybrids with superior popping exhibited higher enthalpies. The amount of unpopped kernels was correlated with the pericarp enthalpy value. Cellulose and arabinoxylan were major components of pericarp as indicated by x-ray. Pericarp structural changes took place in the presence of moisture and heat, and considerable enhancement in the crystallinity occurred after heating in the presence of water. The cellulose component of the pericarp was responsible for exothermal events and increased crystallinity. These pericarp structural changes might strongly influence the moisture migration during microwaving.
Degree
Ph.D.
Advisors
Hamaker, Purdue University.
Subject Area
Food science
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