Quality of minimally processed carrots in perforation-mediated modified-atmosphere packaging (PM-MAP)

Abstract

Studies were carried out to investigate the effect of PM-MAP on minimally processed carrots with different number of perforations (0, 4, 12 and control) on flexible package, stored at 2 °C temperature. The effect of PM-MAP on headspace oxygen and carbon dioxide concentration, weight loss, surface color, firmness, pH, total soluble solid, β-carotene and microbial load were evaluated. It was observed that equilibrium modified atmospheric condition of 5–7 % oxygen and 7.8 % carbon dioxide was achieved in 4 perforation pack. Whiteness index (WI) increased in all the samples from the initial value of 22.75 to a range of 30–35 within 8 days of storage. After that, it remained almost constant for all samples except for 0 perforation packs where a decreasing trend was observed. Chroma value (CV) of samples also followed similar trends like WI and reduced from initial value of 63.08 to a range of 50–55 within 8 days of storage and remained in a constant range during further storage. Firmness of carrot slices decreased to 22–24 N and 25–28 N for 4 and 12 perforation pack respectively from initial value of 30 N after 40 days of storage. Lower oxygen availability in 4 perforation pack was main reason behind lower microbial count (5.2 log₁₀ cfu/g) after 30 days of storage. Reduction of 5.52 % and 10.10 % in β-carotene content was observed in 4 and 12 perforation pack samples. Thus for PM-MAP, 150 g of carrot samples in 4 perforation packs proved to be better than other conditions.