Journal of the Science of Food and Agriculture J Sci Food Agric 84:1741–1749 (online: 2004) DOI: 10.1002/jsfa.1876 Effect of high-pressure treatments on mechanical and functional properties of restructured products from arrowtooth flounder (Atheresthes stomias) Roc´ ıo M Uresti, 1† Gonzalo Velazquez, 1,2 Jos ´ e A Ram´ ırez, 1∗ Manuel V ´ azquez 1,3‡ and J Antonio Torres 2§ 1 Department of Food Science and Technology, U A M Reynosa-Aztl ´ an, Universidad Aut ´ onoma de Tamaulipas, Apdo Postal 1015, Reynosa, Tamaulipas, 88700 Mexico 2 Food Process Engineering Group, Department of Food Science and Technology, Oregon State University. 100 Wiegand Hall Corvallis, OR 97331, USA 3 ´ Area de Tecnolog´ ıa de los Alimentos, Departamento Qu´ ımica Anal´ ıtica, Escuela Polit ´ ecnica Superior, Universidad de Santiago de Compostela—Campus de Lugo, 27002-Lugo, Spain Abstract: Restructured fish products from arrowtooth flounder (Atheresthes stomias), an abundant and subutilized species from the Gulf of Alaska, were obtained by hydrostatic pressure processing (HPP) at 400 and 600 MPa with 0 – 5 min pressure-holding time. Minced fish meat was massaged with 20 g kg −1 salt at 10 ◦ C during 5 min, stuffed in commercial sausage case and HPP-treated. Raw and cooked (90 ◦ C for 15 min) pressure-treated gels were characterized by changes in mechanical properties (texture profile analysis and punch test), protein solubility, electrophoretic profile, expressible water and color. The mechanical properties of raw fish gels increased with pressure level and pressure-holding time while solubility decreased. Myosin aggregation shown by SDS-PAGE was associated with changes in mechanical and functional properties. The values for mechanical properties of heat-induced gels were higher in cooked pressure-treated samples than in the heat-only control.  2004 Society of Chemical Industry Keywords: fish; restructured; high hydrostatic pressure; gelling INTRODUCTION Commercial restructured fish are produced as heat- induced gels in the form of fish fingers and bars of kam- aboko. Restructured fish products have been devel- oped using vacuum tumbling and massaging to solubi- lize and extract myofibrillar proteins with salt to obtain sticky exudates used to bind meat pieces. 1 The use of binding additives has been reported also. 2–4 A con- cern about using minced raw fish to prepare uncooked food is the risk of food-borne diseases associated with microbial contamination during post-capture manip- ulation and processing, particularly during deboning (or filleting and mincing), solubilizing with salt and product forming. However, thermal treatments for gel formation decrease total microbial counts. Hydrostatic-pressure processing (HPP) can reduce microbial loads and could be an alternative to induce gel formation without heat treatment to obtain prod- ucts resembling raw fish. Table 1 summarizes studies reporting pressure effects on the mechanical and func- tional properties of fish proteins. Additional data can be found in the review by Jim´ enez-Colmenero. 5 These studies have shown that HPP induces non-thermal aggregation of myofibrillar proteins affected by pres- sure level and pressure-holding time. Most report treatments at moderate pressure (less than 400 MPa) and for a long time (10–30 min and even more than 1 h). HPP profitability improves for shorter process- ing times even when it requires a higher pressure. 6 Dong et al 7 found that the larvae of the nematode ∗ Correspondence to: Jos ´ e A Ram´ ırez, Department of Food Science and Technology, U A M Reynosa-Aztl ´ an, Universidad Aut ´ onoma de Tamaulipas, Apdo Postal 1015, Reynosa, Tamaulipas, 88700 Mexico E-mail: ramirez@uat.edu.mx † Current address: PMB 374, 501 N Bri ` dge St, Hidalgo, TX 78557, USA. E-mail: ramirez@uat.edu.mx ‡ E-mail: vazquezm@lugo.usc.es § E-mail: J Antonio.Torres@oregonstate.edu Contract/grant sponsor: CONACYT-OMNILIFE; contract/grant number: 35951-B (Received 4 February 2004; revised version received 15 April 2004; accepted 22 April 2004) Published online 4 August 2004  2004 Society of Chemical Industry. J Sci Food Agric 0022–5142/2004/$30.00 1741