Changes in carbohydrates of Navy beans during hydration and subsequent thermal processing

Navy beans were subjected to six different hydration protocols that varied in time, temperature, and methodology after which they were thermally processed in both a brine solution and a typical baked bean sauce. Beans, isolated starch, and hydration fluid were analyzed immediately after the completion of hydration protocols. Significant differences were noted between those protocols utilizing low heat (1 and 2) and those utilizing high heat methods (3-6). Bean from low heat protocols were firmer overall. Starch granules from low heat beans were smaller in overall size, experienced less surface damage retained birefringence, and could absorb more water (higher swell factor). Analysis of the hydration fluid showed no noticeable differences. Analysis of the canned products showed that intense thermal processing effectively caused gelatinization in all protocols as confirmed by DSC and light microscopy. Isolated starch had little to no abilities to retain water. Granules from all protocols in both mediums showed extensive damage, cracking, and possible leaching which is believed to be the cause of substantially lower amylose findings in starch isolated from canned as compared to hydrated beans. Analysis of brine solution revealed increased leaching of carbohydrates, amylose, and proteins. The Kramer compression shear cell detected significant texture differences in beans canned in brine that were hydrated by novel protocols 5 and 6 but not in novel protocol 4, the current protocol (3), and the traditional protocols (1 and 2). Likewise, a probe texture analyzer, determined beans hydrated by protocols 5 and 6 to have firmer skin and flesh overall as compared to the other protocols. The Kramer sheer press was not able to detect differences in beans canned in sauce while the probe texture analyzer was able to detect differences in beans from traditional protocol 1 compared to protocols 3-6. Overall, it was discovered that novel hydration protocols 5 and 6 produce firmer beans when canned in brine solution compared to the current (3) and traditional protocol (1). Beans hydrated by current (3) and novel protocols (4 – 6) show no significant differences in texture when canned in typical baked bean sauce.