Aplicação de alta pressão hidrostática no processamento de vieiras “Nodipecten nodosus” (Linnaeus, 1758)

Abstract

High Hydrostatic Pressure (HHP) is a non-thermal technology used to increase food safety and shelf life. In the fishery industry, HHP has been used for shelling seafood such as oysters and lobsters and extending shelf life of fishes, but it has been little investigated for processing scallops. Scallops are mollusks with high perishability that are typically sold alive or frozen (imported product). The objectives of this research were 1) to evaluate the effect of HHP on scallop quality attributes; 2) to optimize the main processing parameters (pressure level and holding time) to reduce microbial counts while maintaining attributes related to nutritional quality, texture and color and 3) to investigate biochemical and microbiological changes promoted by HHP and their influence on the quality of scallop adductor muscle stored at 4 ° C for 21 days. In Chapter I a review was carried out focused on the application of HHP to bivalve mollusks. In Chapter II, an experimental optimization plan, Box-Bhenken design, was carried out to obtain the most adequate condition for decreasing microbial load and maintaining physical characteristics of the adductor muscle. The adductor muscles were submitted to pressures ranging from 200 to 400 MPa for 0 to 5 min holding time and were compared to a non-processed control. The level of 200 MPa/5 min was efficient for controlling the microbiota, however, it promoted physicochemical modifications in the adductor muscle of the scallop. HHP promoted a slight increase in moisture and pH as well as a decrease in water retention capacity (WHC). The shear force related to the instrumental texture decreased and the Whiteness (W) and brightness (L*) parameters of the muscle increased at a more severe pressure level (400 MPa/5 min). The response surface methodology and the desirability function were used to perform the simultaneous optimization. Desirability indicated conditions of 365 MPa for 2 min as the most suitable condition for efficient processing. In Chapter III, the shelf life of the pressurized adductor muscles at 300 MPa for 2.5 min and 400 MPa/5 min were evaluated for 21 days at 4 ° C using microbiological and biochemical quality parameters in comparison to the control. The microbiota of samples treated by high pressure did not exceed the limit of 106 FCU/g and the quality parameters, N-BVT, pH and TBARS presented values below the established legal limits. The results of this study indicate the level of 300 MPa for 2.5 min as the most adequate conditions to increase the shelf life of refrigerated scallops.