Headspace volatiles along with other instrumental and sensory analyses as indices of maturation of horse mackerel miso

Development of aroma-active compounds during fermentation in the preparation of fermented fish-meat paste product (fish miso) from horse mackerel meat was quantitatively determined and characterized by olfactometric and organoleptic assessments. The critical ripening time was estimated by quantitative and/or qualitative analyses of volatile compounds, peptides, amino acids, product color, and total phenolics of the fish miso matrix throughout fermentation. The results confirmed that the application of koji for the fermentation of horse mackerel meat to produce fish miso significantly reduced the fishy off odor and promoted the development of highly acceptable fish miso with a nutty, cheesy, and fruity aroma. Ethyl acetate, ethyl heptanoate, ethyl decanoate, 2-methylpropanal, 3-methylbutanal, 2,3-butanedione, dimethyl trisulfide, and 3-(methylthio) propanal were identified as key odor-active compounds in fish miso prepared from horse mackerel meat. Among the volatiles, 2-methylpropanal, 3-methylbutanal, and 2,3-butanedione were identified to serve as potential indicators of the maturation of fish miso. Amino acid content could also be a potential indicator of maturation of protein-rich, fermented products such as fish miso. In addition, surface color analysis of fish miso revealed a high correlation between sensory attributes and color components. Specifically, r and b values were considered potential indicators of maturation. Practical Application: Variability is a major drawback in fermented products such as fish miso and it requires establishing the optimum ripening time, defined as that providing the aroma attributes qualitatively and quantitatively mostly appreciated by consumers. We have carried out this work for comprehensive determination of the critical ripening time by applying several instrumental and sensory tools including quantitative and/or qualitative analysis of volatile compounds, peptides, amino acids, product color, and total phenolics of the fish miso matrix throughout the fermentation period. The outcome of the present study can be efficiently applied for detection of maturation in similar types of fermented product for large-scale production.