Development of modified atmosphere packaging (MAP) on shelf-life extension of pla-duk-ra (dried fermented catfish) stored at room temperature

Abstract

Pla-duk-ra (a typical dried fermented catfish), one of the most popular fermented foods consumed in Thailand, is normally easy to spoilage within 1–2 month at room temperature due to its compositions (7.63% NaCl with pH and Aw of 6.24 and 0.82, respectively). This study aimed to evaluate the potential of using modified atmosphere packaging (MAP) and vacuum packaging (VP) to extend product's shelf-life. Therefore, changes in physical, chemical, microbiological characteristics as well as sensory’ acceptability of dried fermented catfish packed under MAP condition at the level of CO2: O2: N2 = 80:0:20 (MAP 80–0), 80:10:10 (MAP 80–10), 90:0:10 (MAP 90–0) and 90:5:5 (MAP 90–5) as well as VP condition stored at room temperature were monitored, compared with two traditional packaging (polypropylene bag (Con-PP) and nylon/LLDPE bag (HS)). The result found that Con-PP and HS underwent spoilage within 30 and 60 days, respectively, as indicated by the exceed of yeast and mold (>3.00 log CFU/g sample). Samples packed in MAP and VP condition had the slower rate of quality changing, e.g., the increase in pH, oxidation products (PV and TBARS values), browning index and microbial counts, etc., compared with traditional packaging (P < 0.05). Among all samples, MAP-90 and VP are only 2 samples which can preserve the quality of dried fermented catfish up to 90 days (without any spoilage). Moreover, MAP 90-10 seem to be the highest potential packaging for this product, as indicated by the higher score in sensory evaluation (especially flavor-liking score), compared with others. This study indicated the potential of using MAP technology for fermented product packaging.