Impact of sous vide cooking on quality and shelf-life of dried sour-salted fish

Quality changes of dried sour-salted fish, a typical traditional fermented fish in Thailand, packed under vacuum condition (Con-La), and treated with the sous vide (SV) technique at 40℃ for 30–120 min (S4-30, S4-60, S4-90 and S4-120) and 60℃ for 15–30 min (S6-15 and S6-30) during storage at room temperature (28–30℃) for 1 month, were monitored and compared with traditional packaging (polypropylene bag with hot sealed; Con-PP). The result found that Con-PP underwent spoilage within 1 week by exceeding yeast and mold (>500 CFU/g sample). Among all samples, S4-90, S4-120, S6-15, and S6-30 exhibited the greater increase in pH, peroxide value and TBARS, browning intensity (A₄₂₀), and microbial population than others (p < .05), resulting in limitation of shelf-life themselves (3 weeks), whereas samples stored in vacuum packed (Con-La) and having mildly SV cooking (S4-30 and S4-60) can prolong the shelf-life of this product up to 4 weeks. Additionally, the two latter had the greater sensory scores, suggesting more consumer's perception. Thus, vacuum packaging, incorporated with an optimal level of SV cooking, revealed the great potential for quality improvement and shelf-life extension of dried sour-salted fish.

Practical applications

This study investigated the potential of using the sous vide technology on shelf-life extension and quality improvement of fermented food, which finally provides a useful strategy to food industries in their quest to meet the suitable packaging and processing for each product. The result revealed that using vacuum packaging, incorporation with SV cooking at 40℃ for 30 and 60 min can prolong the shelf-life of dried sour-salted fish, which normally spoilage within 1 week, up to 4 weeks at room temperature. Moreover, sous-vide samples exhibited better desirable characteristics, especially flavor and odor, assessed by consumer's sensory evaluation.