Extended shelf life of soy bread using modified atmosphere packaging.
This study investigated the use of modified atmosphere packaging (MAP) to extend the shelf life of soy bread with and without calcium propionate as a chemical preservative. The bread samples were packaged in pouches made from low-density polyethylene (LDPE) as the control (film 1), high-barrier laminated linear low-density polyethylene (LLDPE)-nylon-ethylene vinyl alcohol-nylon-LLDPE (film 2), and medium-barrier laminated LLDPE-nylon-LLDPE (film 3). The headspace gases used were atmosphere (air) as control, 50% CO2-50% N2, or 20% CO2-80% N2. The shelf life was determined by monitoring mold and yeast (M+Y) and aerobic plate counts (APC) in soy bread samples stored at 21 degrees C +/- 3 degrees C and 38% +/- 2% relative humidity. At 0, 2, 4, 6, 8, 10, and 12 days of storage, soy bread samples were removed, and the M+Y and APC were determined. The preservative, the films, and the headspace gases had significant effects on both the M+Y counts and the APC of soy bread samples. The combination of film 2 in the 50% CO2-50% N2 or 20% CO2-80% N2 headspace gases without calcium propionate as the preservative inhibited the M+Y growth by 6 days and the APC by 4 days. It was thus concluded that MAP using film 2 with either the 50% CO2-50% N2 or 20% CO2-80% N2 was the best combination for shelf-life extension of the soy bread without the need for a chemical preservative. These MAP treatments extended the shelf life by at least 200%.
Department of Food Science and Technology, Ohio State University, 2015 Fyffe Road, Columbus, Ohio 43210, USA.
Ursula
U
Fernandez
Yael
Y
Vodovotz
Polly
P
Courtney
Melvin A
MA
Pascall
D001939:Bread / Q000382:microbiology / Q000592:standards; D002245:Carbon Dioxide / Q000378:metabolism; D015169:Colony Count, Microbial; D005516:Food Microbiology; D018857:Food Packaging / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D005520:Food Preservatives / Q000494:pharmacology*; D005658:Fungi / Q000254:growth & development; D006801:Humans; D006813:Humidity; D009584:Nitrogen / Q000378:metabolism; D011422:Propionates / Q000494:pharmacology*; D045730:Soy Foods / Q000382:microbiology / Q000592:standards; D013696:Temperature; D013997:Time Factors; D015003:Yeasts / Q000254:growth & development
D005520:Food Preservatives; D011422:Propionates; D002245:Carbon Dioxide; C514136:calcium propionate; C029658:propionic acid; D009584:Nitrogen