Vacuum impregnation as a tool to introduce biopreservatives in gilthead sea bream fillets (Sparus aurata)

Abstract

The aim of this study was to determine the possible technological uses of biopreservation and vacuum impregnation techniques to extend shelf life of gilthead sea bream fillets. Two impregnation media were studied: a solution containing lactic acid bacteria (LAB) and a nisin solution. Vacuum impregnation was carried out at 4 °C. Fillets were immersed in a vessel containing the impregnation solution and vacuum was applied during 5 min. After this time atmospheric pressure was restored leaving samples under the liquid for 5 min more. Weight gain, physico-chemical properties (moisture, pH, water activity and TVBN), color and microbiological counts were studied during 15 days of storage at 4 °C. The quantities of biopreservative added to the product after impregnation were about 2.16 × 107 CFU/100 gfish for LAB solution and 5294 IU nisin/100 gfish or 0.13 mgnisin/100 gfish for nisin solution. Changes on physico-chemical properties were not significant between fillets impregnated and fillets without impregnation. Impregnation of fillets caused small changes in color attributes, specially an increase the luminosity (L*). Vacuum impregnation with biopreservative solutions can extend the shelf life of gilthead sea bream fillets, reducing the initial count and/or delaying the growth of microorganisms.