Effect of single-cycle and multiple-cycle high-pressure treatments on the colour and texture of chicken breast fillets Ana Del Olmo, Pilar Morales, Marta Ávila, Javier Calzada, Manuel Nuñez ⁎ Departamento de Tecnología de Alimentos, INIA, Carretera de La Coruña Km 7, Madrid, 28040, Spain abstract article info Article history: Received 7 July 2009 Accepted 24 January 2010 Editor Proof Receive Date 8 February 2010 Keywords: High pressure Chicken breast Colour Texture High-pressure processing, a useful tool to improve the microbiological quality and safety of foods, may also bring about changes in the colour and texture of foods, which might influence their acceptability by consumers. In the present work, the effect of single-cycle and multiple-cycle high-pressure treatments at 400 MPa on the colour and texture of chicken breast fillets was investigated. Colour parameters L*, a* and b* were significantly higher for all pressurized fillets than for the vacuum-packaged control fillets. When single- cycle treatments were applied, maximum values of texture parameters were generally found for fillets pressurized for 10 or 15 min, depending on whether Kramer or Warner-Bratzler cells were used, and decreased for fillets submitted to longer cycles. In the case of multiple-cycle treatments, texture parameters initially increased with the number of 1-min cycles, but fillets submitted to the most severe treatments showed lower values. Industrial relevance: The objective of the present study was to evaluate the effect of single-cycle and multiple-cycle high-pressure processing at 400 MPa on the colour and texture of chicken breast fillets. Significant changes in colour occurred even for the shortest treatment applied, a 1-min cycle. Texture parameters increased with length of treatment, but beyond a certain severity of treatment these parameters declined. Acceptability by consumers, and marketing of high-pressure treated chicken breast fillets, might be negatively affected by changes in visual appearance. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction High-pressure (HP) processing, a non-thermal food preservation procedure, is an adequate tool to reduce microbial contamination in foods which might be altered by heat treatments. By eliminating pathogenic bacteria, the microbiological safety of foods can be improved (Knorr, 1993). In the particular case of chicken meat, the prevalence of pathogens such as Salmonella may be high (Antunes, Réu, Sousa, Peixe, & Pestana, 2003; Capita, Alvarez-Astorga, Alonso- Calleja, Moreno, & García-Fernández, 2003; Naugle, Barlow, Eblen, Teter, & Umholtz, 2006). High-pressure processing of chicken breast fillets inoculated with Salmonella achieved 4.0 and 4.6 log reductions after one 10 min-cycle and three 3 min-cycles at 400 MPa, respec- tively, with no recovery of injured cells during later refrigerated storage (Morales, Calzada, Rodríguez, De Paz & Nuñez, 2009). Also, the shelf life of chicken meat can be prolonged by HP processing (O'Brien & Marshall, 1996). According to these authors, untreated raw ground chicken with an initial microbial load of 5.25 log cfu/g showed counts close to 7.5 log cfu/g after 7 days at 4 °C, whereas they remained below 7 log cfu/g after 70 days at 4 °C in raw ground chicken pressurized at 408 MPa for 10 min. Similarly, bacterial counts in minced chicken pressurized at 500 MPa for 15 min at 40 °C did not increase significantly after storage for 6 months at 3 °C, whereas they reached 7 log cfu/g after 8 days at 3 °C (Linton, McClements, & Patterson, 2004). Multiple-cycle HP treatments may be more effective than single- cycle treatments of the same dwelling time. This has been proven for the elimination of Salmonella in liquid whole egg (Ponce, Pla, Sendra, Guamis, & Mor-Mur, 1999; Bari, Ukuku, Mori, Kawamoto, & Yamamoto, 2008) or in chicken breast fillets (Morales et al., 2009), and of Escherichia coli O157:H7 in ground beef (Morales, Calzada, Avila, & Nuñez, 2008). However, multiple-cycle treatments did not perform better than single-cycle treatments for the reduction of the population of mesophile and psychrotroph bacteria in mechanically recovered poultry meat (Yuste et al., 2001). High-pressure processing may affect the colour and texture of foods (Knorr, 1993). Information on the effect of HP on the colour and texture of chicken meat is scarce. Regarding the colour, it has been shown that treatments at 500 MPa for 60 min at different temperatures increased lightness and reduced redness and yellowness of minced chicken thighs (Beltran, Pla, Capellas, Yuste, & Mor-Mur, 2004). Hardness of chicken breast muscle increased with both HP and heat treatments, which acted synergistically at temperatures from 20 to 50 °C, although it decreased when pressures above 200 MPa were applied at temperatures of 60 or 70 °C (Zamri, Ledward, & Frazier, 2006). Innovative Food Science and Emerging Technologies 11 (2010) 441–444 ⁎ Corresponding author. Tel.: + 34 91 3476799. E-mail address: nunez@inia.es (M. Nuñez). 1466-8564/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ifset.2010.01.012 Contents lists available at ScienceDirect Innovative Food Science and Emerging Technologies journal homepage: www.elsevier.com/locate/ifset