Effect Addition of Lactic Acid and Pomegranate Peel Extract Combined with Paprika Powder on the Safety and Quality of Refrigerated White Grouper Fish (Epinephelus aeneus).

Abstract

White grouper (Epinephelus aeneus) is an economically important fish found in the southern Mediterranean Sea. This study was done to assess the effect of lactic acid buffer (LAB), pomegranate peel extract combined with paprika powder (PPP), and their combinations on the safety and quality of white grouper stored at 4 ℃. Fresh fish was treated with LAB (2 %, 4 %, 6 %, and 8 %), pomegranate peel extract (100 mg/kg) combined with paprika powder (5 g/kg) (PPP) and combinations of LAB with PPP. Microbiological quality, pH value, and organoleptic characteristics were assessed during refrigerated storage. Results showed that psychotropic aerobic bacteria; H2S-producing bacteria and Enterobacteriaceae were strongly inhibited by all treatments applied, which would enhance safety, quality and prolong the shelf life of fish. The highest inhibition was observed with 8% LAB combined with PPP. pH reductions of 0.64, 1.14, 1.61 and 1.99 were observed by treatment with 2%, 4%, 6%, and 8% LAB, respectively. The sensory evaluation showed that lowering the pH to 4.38 did not influence the organoleptic properties of fish, which was supported by the microbiological changes. Fish treated with either 2% LAB or PPP could be refrigerated safely for 7 days at 4 ℃, as compared to 6 days with the untreated samples. Increasing LAB concentration to 4, 6, and 8% increased the shelf life to 8, 9 and 10 days, correspondingly. Additionally, combining LAB (2%,4%, 6%, and 8%) with PPP could further expand the shelf life to 8, 9, 10 and 11 days, respectively.