A new alternative technique for extending shelf life of white fresh cheese without salting: Reducing atmosphere packaging (RAP)

In this study, for the first time in the world Reducing Atmosphere Packaging (RAP) technique based on the use of a gas mixture containing reducing gas (H2) for preservation of the fresh white cheese without salting step was evaluated. The white cheese samples after preparation were immediately packaged in Reducing Atmosphere Packaging (MAP), Modified Atmosphere Packaging (MAP), and unpackaged (control) conditions without adding salt, brine or any preservatives. Six different sample groups: RAP 1 (%90 CO₂, %6N₂, %4 H₂), RAP 2 (%50 CO₂, %46 N₂, %4 H₂), MAP 1 (%90 CO₂, %10 N₂), MAP 2 (%50 CO₂, %50 N₂), MAP 3 (air) and CONTROL (Unpackaged/+4°C) were assigned and stored for 7 weeks at +4 C cold conditions. The dry matter, fat content, titratable acidity, color (L* and b*) and microbiological analyses (total mesophilic-aerobic bacteria (TMAB) and yeast-mold count) of the samples were evaluated. Color analysis showed that while L * value decreased, b* value increased for all sample groups. According to the titratable acidity results, an increase in titratable acidity was observed over time for all sample groups. In terms of both color parameters and titratable acidity; the closest values to the fresh sample group (time 0) was observed for RAP 1 group (p<0.01). The results of microbiological analysis showed that the TMAB content of all sample groups inceased along the time with the highest and lowest TMAB content observed for CONTROL (Unpackaged/+4°C) and RAP 1 samples, respectively. Yeast-Mold content of all sample groups increased along the time; where RAP 1 exhibited the lowest content and was similar to RAP 2 group (p<0.01). In the light of the results obtained from all analyses; the similarity between samples packed under reducing atmosphere conditions (RAP 1 and RAP 2) and the fresh samples (time 0 week) attracts attention to the importance role of hydrogen (H2) in preserving fresh cheese. The use of H2 besides CO2 extended the shelf life of the white fresh cheese without using any preservatives. The results of the present study prove the possibility to store the fresh white cheese for 6 weeks with keeping its sensorial and microbiological qualities. These results provide also a healthy and alternative product to many types of patients who are sensitive to salt consumption such as high blood pressure, Chronic kidney and Cardiovascular diseases.