1H-Nmr Spectroscopy to Measure the Ki Index of Bombay Ducks During Chilling Storage As An Approach to Determine Freshness

Abstract

The quality of fish freshness plays a crucial role in the acceptance of consumers and human health. Considering that food safety has recently become a major concern on a global scale, establishing and evaluating fish freshness is crucial for research and development. Some methods that can be used to assess fish freshness are the K-values and the Ki index. Those methods evaluate the fish freshness based on the degradation of nucleosides in fish that occurred during the deterioration process. This study aimed to assess quality freshness (Ki index) in Bombay duck (Harpodon nehereus), one of the tropical fisheries products, using concentration nucleosides in chilling temperature storage conditions for 12 days. Analysis of nucleosides in this study was conducted using a 1 H-NMR (Nuclear Magnetic Resonance) metabolomics approach. Four nucleosides (Inosine, Hypoxanthine, inosine 5' monophosphate, and ATP) were successfully analyzed during this study. This study showed Hypoxanthine was slightly fluctuated, IMP Increased until 4 days then decreased markedly, ATP decreased markedly up to 6 days, then relatively stagnant in the remaining storage and inosine decreased up to 4 days, significantly increased from 6 days until 12 storage. Furthermore, freshness calculation showed that the Ki index of Bombay duck fish significantly increased during chilling storage conditions from 0 days to six days (47% - 94%). Furthermore, the Ki index showed a stable pattern from 6 – 12 days of storage (94% - 95%). The Ki index of Bombay duck value exceeded 80% after storing the fish for four days. Therefore, based on these calculations after 4 days storage in the chilling temperature Bombay ducks is categorized as the fish which is not fresh anymore.