JOURNAL OF FISHERIES AND ENVIRONMENTVolume 45, No. 02, Month MAY, Year 2021, Pages 1 - 17
Preliminary study of some aroma compounds of salted shrimp paste (kapi): using chemometrics to categorize characteristics of different manufacturers
Walai Kleechaya, Nongnuch Raksakulthai, Jiraporn Runglerdkriangkrai
Abstract Download PDFShrimp paste (kapi) is a fermented condiment made from planktonic shrimp widely used in Southeast Asian cooking. Its flavor is formed from a complex combination of aroma compounds (ACs). The present study examined kapi that was produced by six manufacturers that used different shrimp species and varying ratios of shrimp and salt. A preliminary study of AC was conducted using GC-MS during six months of fermentation. Correlations were found among production factors and significant ACs determined by chemometric methods. Thirty-six peaks were detected in kapi samples, with only 11 ACs playing an important role in odor. S-containing compounds (dimethyl disulfide and dimethyl trisulfide) and aldehydes (2-methyl-propanal, 3-methyl-butanal, and 2-methyl-butanal) were the key ACs in all types of kapi. Eleven ACs were discriminated effectively by principal component analysis (82.02 % cumulative variance), hierarchical cluster analysis, and linear discriminant analysis (99.66 % cumulative variance). Kapi samples produced from the same species (Acetes sp.) and salt quantity showed the best AC correlation. The formula with added sugar showed the highest content of N-containing compounds (N, N-dimethyl methylamine, 3-ethyl-2,5-dimethyl pyrazine) and S-containing compounds, whereas 2,3-butanedione was only found in kapi produced from Mesopodopsis sp., which was also sun-dried for a longer period. Thus, the developed aroma of kapi was significantly affected by the species of planktonic shrimp, the formulation, and the fermentation period. It should be noted that this study used SPME GC-MS technique with DB-1ms capillary column and thus may have captured only a small fraction of the ACs present in kapi.
HS-SPME/GC-MS, Multivariate statistical analysis, Planktonic shrimp, Volatile compound