Quality of Green Beans And Energy Required For High Temperature Processing

Abstract

The objectives of this research were to compare processing of green beans at 15 psig with processing at ten psig to determine if differences in ascorbic acid retention, energy consumption and eating quality would result. Green beans were processed, according to current USDA recommendations (ten psig for 20 minutes), at ten psig for 43 minutes, and at 15 psig for 15 minutes. A significant difference among the three treatments was found in energy consumption, with processing beans at ten psig for 43 minutes requiring significantly more energy than the other two treatments. There were no significant differences among the three treatments in ascorbic acid retention as determined by the 2,4 dinitro‐phenyl hydrazine method, and in eating quality as indicated by the results of triangle sensory tests, or in Warner‐Bratzler shear values.

Antioxidant Activity of Processed Table Beets (Beta vulgaris var, conditiva) and Green Beans (Phaseolus vulgaris L.)

“…Thermal processing of green beans under constant temperature of 115 °C at various time intervals of 10, 20, and 40 min showed a small but significant initial reduction of vitamin C content ( p < 0.05) followed by a increase to pre-thermal processing levels ( Table ), which is consistent with previous studies ( , ). The commercial processing conditions of canned green beans were 115 °C for 20 min (5.00 ±.…”

“…Leaching of vitamin C during blanching prior to packaging for processing is also a key step in vitamin C loss. The estimated D 115°C value for canned beets (the time taken for 90% reduction of the initial vitamin C content at 115 °C) was approximately double of the previously reported values of 218-276 min (35,(6)(7) and even longer values for canned green beans because there was no degradation of vitamin C. The consistent values reported for vitamin C content in green beans among the thermal heating conditions was reinforced by previous findings that time and temperature parameters contribute directly very little to vitamin C degradation (33).…”