Development of Fermented Dried Salted Spanish Mackerel and Analysis of Its Flavor Compounds, Fermentation Conditions, and Preparation of a Directed Vat-Set Starter

In this study, fermented, dried, salted Spanish mackerel (FDSSM) was prepared using a composite fermentation agent, and its flavor compounds, fermentation conditions, and preparation of a directed vat-set starter were investigated. The results showed that adding a combination of Lactobacillus sakei (LS), Pediococcus pentosaceus (PP), and Lactobacillus casei (LC) at a ratio of 1:1:1 yielded FDSSM with the best sensory quality. LS+PP+LC samples exhibited the highest 5′-IMP and HX content at 492.07 and 526.36 mg/100 g, respectively, and the lowest TBARS content at 0.76 mg/100 g. A total of 77 flavor compounds were detected across the five samples. The key flavor compounds in the FDSSM were 3-methylbutanal, n-hexanal, n-heptanal, n-octanal, nonanal, 1-octen-3-ol, and heptanol. The optimal fermentation conditions for FDSSM were a fermentation time of 5.5 h, a fermentation temperature of 28.5 °C, and a strain addition amount of 4%. The optimal composite protectant for the directed vat-set starter was 15% inulin, 5% gum arabic, 5% skim milk powder, and 5% sodium glutamate at a 1:1:1:5 ratio, yielding the highest microbial protection rate of 69.86 ± 0.23%. The optimal storage temperature for the directed vat-set starter was −20 °C. The viable bacterial count in starter cultures stored for 60 days exceeded 109 CFU/g. The addition of a directed vat-set starter yielded FDSSM with superior sensory quality compared with mixed bacterial cultures. These findings provide a theoretical foundation for the large-scale industrial production of FDSSM.