Effect of modified atmosphere packaging on sensory quality, chemical parameters and shelf life of carrot roots (Daucus carota L.) stored at chilled and abusive temperatures

Abstract

The influence of short-term storage in air atmosphere and modified atmosphere (MA) conditions obtained by different film perforations and storage conditions on carrot root quality was studied. The carrots were stored at temperature conditions simulating the commercial distribution chain. The quality was evaluated using chemical analyses, descriptive sensory analyses and evaluation of decay at the end of storage. One kilogram of carrots were packaged at a commercial packing house in pouches with (1) 13 laser perforations, (2) 11 warm needle perforations and 3) approximately 560 warm needle perforations per 10×10cm (“bread pouch”). The packages were stored at optimal (chill) storage conditions of 4°C for 6d followed by 6°C for 9d, or at an abusive temperatures (common retail storage) conditions of 4°C for 3d, 20°C for 3d and 6°C for 9d. The highest weight loss during storage was observed for the “bread” perforated packages stored at retail conditions (2.3%) and at chill conditions (1.4%). The weight loss was below 0.34% for all the other packages with different perforation and storage combinations. The gas concentration in the needle perforated packages was close to air both at chill and retail storage conditions. In laser perforated packages at chill conditions, the O2-concentration stabilised at 12–13kPa and the CO2-concentration at 9–10kPa, whereas at abused temperature the O2 concentration decreased to 4kPa the last day of storage at 20°C (day 6) and CO2 concentration approximately at 32kPa at day 6. The low O2 concentration and high CO2 concentration in laser perforated packages stored at retail conditions and the high ethanol content measured in these carrots could indicate anaerobic respiration. These carrots also had significantly higher scores for ethanol odour and flavour. The carrots in laser and needle perforated packages stored at chill conditions had the highest scores for terpene odour and flavour. Percentage diseased carrots were highest in the laser perforated packages stored at retail conditions. The experiment showed that the overall carrot quality was best maintained in needle perforated packages with a gas atmosphere close to air, giving no major weight loss, no ethanol formation and the lowest incidences of storage diseases at both chill and retail conditions.