Combined effects of coating, modified atmosphere packaging, and gamma irradiation on quality maintenance of ready-to-use carrots (Daucus carota).
The objective of this study was to evaluate the effect of an edible coating combined with modified atmosphere (MA; 60% O2, 30% CO2, and 10% N2) packaging and gamma irradiation on the microbiological stability and physicochemical quality of minimally processed carrots. A coating based on calcium caseinate and whey protein isolates was used. Coated and uncoated peeled minicarrots were packed under the MA or air (78.1% N2, 20.9% O2, and 0.036% CO2), irradiated at 0.5 or 1 kGy, and stored at 4 +/- 1 degrees C for 21 days. Samples were evaluated periodically for aerobic plates counts (APCs) and physicochemical properties (firmness, white discoloration, and whiteness index). Gamma irradiation did not significantly affect the physicochemical properties of the carrots (P > 0.05). Microbiological analysis revealed that for uncoated carrots irradiation at 0.5 and 1 kGy under air and MA reduced the APCs by 3.5 and 4 log CFU/g and by 4 and 4.5 log CFU/g, respectively. For coated carrots, irradiation at 0.5 and 1 kGy under air and MA reduced the APCs by 4 and 4.5 log CFU/g and by 3 and 4.25 log CFU/g, respectively. The coating was able to protect carrots against dehydration during storage under air. Coating and irradiation at 1 kGy were also able to protect carrot firmness during storage under air. MA packaging retarded whitening of uncoated carrots but had a detrimental effect on firmness. The edible coating used in this study did not significantly inhibit (P > 0.05) microbial growth on carrots.
Lafortune
R
R
Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Quebec, Canada.
Caillet
S
S
Lacroix
M
M
D002245:Carbon Dioxide / Q000378:metabolism; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D018552:Daucus carota / Q000382:microbiology* / Q000528:radiation effects / Q000592:standards; D004307:Dose-Response Relationship, Radiation; D005511:Food Handling / Q000379:methods; D005514:Food Irradiation; D005516:Food Microbiology; D018857:Food Packaging / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D005520:Food Preservatives / Q000494:pharmacology*; D005720:Gamma Rays; D006801:Humans; D010100:Oxygen / Q000378:metabolism; D011786:Quality Control; D013997:Time Factors
D005520:Food Preservatives; D002245:Carbon Dioxide; D010100:Oxygen