Effect of processing methods on the volatile components of Ethmalosa fimbriata using a two‐dimensional gas chromatography‐time‐of‐flight mass spectrometry (GC × GC‐TOF‐MS) technique

Influence of Drying Techniques on the Physicochemical, Nutritional, and Morphological Properties of Bighead Carp (Hypophthalmichthys nobilis) Fillets

Different experiment analyses were performed to evaluate the influence of two drying techniques (oven drying and microwave drying) on the fillets of bighead carp fish (Hypophthalmichthys nobilis). The processed and fresh samples were subjected to the chemical analysis of (amino acids, minerals, volatile compounds, fatty acids, and vitamins) as well as scanning electron microscopy, thermal analysis, and color measurement, in order to identify nutritional components that can be additives or supplementary in food industries. The drying techniques increased the protein content significantly. Amino acids were identified, and the level of essential amino acid (EAA) was higher under the microwave treatment compared with the oven drying process. The Ca+2 and K+1 were presented in high values, followed by Na+1 and Mg+2. In addition, the drying techniques showed and released more volatile compounds in the processed samples compared with the unprocessed samples. Under the drying process, polyunsaturated fatty acids were increased in the processed fillets, whereas the level of saturated and monounsaturated fatty acids reduced. Thermal degradation occurred from 100 to 150 °C. However, the processed samples were subjected to an intensive endothermic response, but remained stable until 100 °C. Therefore, the microwave technique showed some enhancements in the nutritional value and has the potential to be applied as an effective preservation method of bighead carp fish. Furthermore, dried fillets could be an alternative source of bighead carp fish for the food industry.

Contribution of the volatile components from fresh egg, adult female and male of Pestarella tyrrhena to odour production

Shrimps, including Pestarella tyrrhena, are highly susceptible to deterioration whereas odour production has been indicated as one of the factors determining the perishability and bait potential of shrimps. In this study, volatile components generated from fresh egg, adult female and male of P. tyrrhena were assessed using two-dimensional gas chromatography coupled to time-of-flight mass spectrometry to understand their contribution to odour production. Alkenes, alkynes, alcohols, aldehydes, a ketone, acids, esters, an amine, sulphur-containing and miscellaneous compounds were detected. Meanwhile, adult females and males of P. tyrrhena had a higher number of these volatile compounds. The detection of 2-methyl propan-1-ol with pungent odour only in the male sample of P. tyrhenna suggests that the male of this shrimp species may not completely attract fishes to hooks. Overall, the study established shrimp developmental stage and sex as additional factors influencing the production of volatile compounds, flavour/aroma/odour and fishing bait attributes of P. tyrrhena. Detection of N-nitrosodimethylamine (a carcinogen) in the shrimp samples, particularly the adult male, calls for caution in their direct human consumption and use as fishing bait.