Extending Oxidative Stability of Fish Burgers Using Propolis Ethanolic Extract during Storage

Processed ready-to-eat seafood is one of the most important sources of animal proteins for humans, which synthetic preservatives are used to extend their shelf-life. In the current study, possibleuse of a natural preservative compound (propolis ethanolic extract) was investigated.

After formulating and preparing fish burgers, various freeze-dried propolis powder concentrations (0, 0.1, 0.2 and 0.4 g/100 g) were added to the grounded fish fillets. Prepared samples were packed in polyethylene bags and stored at -18oC ±1. Then, relevant qualitative factors of the samples were assessed at various time intervals (0, 30, 60 and 90 days).

Replacement of propolis powder (0.4 g/100 g) was able to decrease peroxide and TBA values to nearly 31.77 and 22.71% during 90 days of storage. The highest amount of total volatile nitrogen index(corresponding to the lowest pH) was related to the control sample (on the 90th day of storage). Also, the result show that, there was no statistically significant difference (p>0.01) between the samples in terms of color changes.

Based on the results of sensory evaluation and quality assessment, using 0.2–0.4 (g/100 g) of propolis powder can be recommended for the industrial production of fish burgers.