Extended Shelf Life of Soy Bread Using Modified Atmosphere Packaging
Abstract: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°C ± 3°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%.
Document Type: Research Article
Affiliations: Department of Food Science and Technology, Ohio State University, 2015 Fyffe Road, Columbus, Ohio 43210, USA