Microcalorimetry as a tool to measure shelf-life at postharvest of green asparagus

There are many methods to store and extend the postharvest life of asparagus spears, but their effectivity is measured by variables that do not reflect spears' senescence. The objective of the experiment was to utilised isothermal microcalorimetry as a tool to objectively measure the quality loss of asparagus spears during postharvest storage. Asparagus spears cv. Brock were stored at 2 degrees C and 5 degrees C and 90% humidity for 16 days. Metabolic heat and metabolic efficiency of asparagus spears were measured during 16 days. Also, water status, total soluble solids (TSS%), titratable acidity (TA%), pH, sugars, and space colour variables were recorded. We found a determination coefficient of 0.79 and 0.87 between metabolic heat and respiration rate in whole spears stored at 2 degrees C and 5 degrees C by a polynomic regression. It was recorded a regression between metabolic heat and fructose (0.5) and glucose (0.67) at 2 degrees C and fructose (0.79) and glucose (0.76) at 5 degrees C and sugar content. We detected slight changes in quality parameters (pH, Acidity, TSS), weight loss, and turgor pressure during storage. It was concluded that parameters obtained through isothermal microcalorimetry were sensitive and reliable indicators to detect changes in postharvest parameters commonly used to evaluate changes in asparagus spears quality.