Effect of high-pressure pretreatment on enzymatic hydrolysis of a mixture of rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) rest raw material

Abstract

IntroductionFish rest raw material generated from the fish processing industry may be a useful resource for recovery of added value compounds. The application of non-thermal novel technologies can improve the extraction. High-pressure processing (HPP) has long been used for the preservation and extension of the shelf life of seafood. It also constitutes a promising technology for the increased recovery of valuable compounds, such as lipids and proteins. The objective of this study was to assess the yield and the chemical composition of the fractions obtained after enzymatic hydrolysis on a mixture of Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) rest raw material pretreated by high-pressure (HP).MethodsSix different pretreatments were applied prior to enzymatic hydrolysis; 600 MPa x 8 min, 600 MPa x 4 min, 400 MPa x 8 min, 400 MPa x 4 min, 200 MPa x 8 min, 200 MPa x 4 min.Results and discusssionThese applied pretreatments did not yield higher oil extraction compared to the control. However, the fish protein hydrolysates (FPH) contained higher amount of protein when compared to the FPH obtained from the control.

Quality Assessment of Fish Oil Obtained after Enzymatic Hydrolysis of a Mixture of Rainbow Trout (Oncorhynchus mykiss) and Atlantic Salmon (Salmo salar) Rest Raw Material Pretreated by High Pressure

“…Fresh Atlantic salmon and rainbow trout rest raw material, including heads, tails, skin, bones, and trimmings, were minced in a ratio of 1:1 w / w . This same raw material was previously utilized in a study by Kotsoni, Daukšas, Aas, Rustad, Tiwari and Cropotova [ 21 ] and underwent HPP prior to enzymatic hydrolysis, as detailed in their research. The HPP was conducted at pressures of 200, 400, and 600 MPa, with hold times of 4 and 8 min.…”

“…To optimize the quality of the final product, the hydrolysis process was conducted away from direct sunlight and flushed by nitrogen. Furthermore, chamomile and oregano extracts, prepared as described by Kotsoni, Daukšas, Aas, Rustad, Tiwari and Cropotova [ 21 ], served as natural antioxidants in a 1:1 ratio and were introduced in the hydrolysis vessel at a concentration of 1.5 mL/kg of raw material. A portion of the oil fraction obtained after enzymatic hydrolysis from the previous study by Kotsoni, Daukšas, Aas, Rustad, Tiwari and Cropotova [ 21 ] was set aside for a storage period of 8 weeks to assess changes in quality.…”

“…The quantity of oil released is often linked to the degree of protein denaturation, influenced by the conditions of the applied HPP [ 20 ]. However, in our earlier publication the oil yield was mostly unaffected by HPP [ 21 ]. This process can induce lipid oxidation, particularly affecting PUFAs abundant in fish oil, which may alter the sensory and nutritional properties of the oil [ 22 ].…”