Effects of exogenous calcium salt treatments on inhibiting irradiation-induced softening in diced Roma tomatoes

Freshly diced tomatoes were dipped into either 0.2% or 1% calcium chloride or 2% calcium lactate solution and exposed to gamma-irradiation at 1.25 kGy. With increasing levels of calcium, firmness was enhanced, water-soluble pectin was decreased, and oxalate-soluble pectin was increased. Irradiation decreased instrumental firmness in all samples; however, the 1% calcium chloride and 2% calcium lactate-dipped samples remained firmer than the water-dipped control. Irradiation alone did not have a significant impact on pectic substances. Trained sensory panelists did not detect a significant loss of firmness due to irradiation in the calcified tomatoes, but some judges detected a change in flavor following the calcium dips.