Feeding a high oleic acid (C18:1) diet improves pleasing flavor attributes in pork
Introduction
Flavor is one of the main drivers in consumer preferences for meats. Tenderness, juiciness, and roast flavor positively influence customer preference (Aaslyng et al., 2007). All these characteristics are closely linked to the meat composition, especially the intramuscular fat abundance and degree of fatty acid (FA) saturation (Song et al., 2017). Tikk and co-workers established a link between specific FA profiles and flavor attributes in pork (Tikk et al., 2007). In particular, the degree of unsaturation of FA appears to have a major influence on taste characteristics (Mottram, 1998). A high level of the monounsaturated fatty acid (MUFA) oleic acid (C18:1), together with a low level of polyunsaturated fatty acid (PUFA) linoleic acid (C18:2) affected the production of volatile compounds and the resulting pork ham flavor (Benet et al., 2015). In brief, a high MUFA/PUFA ratio improved the release of pleasant aromatic notes from Maillard reactions in cooked ham (Benet et al., 2016).
The FA profile in pork adipose tissue and muscle can be modified by changing the fatty acid profile of the pig diet (Cava et al., 1997). Previous research showed that levels of the PUFA linoleic acid (C18:2) in pork tissues increased linearly with dietary inclusion (Wood and Wiseman, 1984). In contrast, dietary MUFAs (i.e. C16:1 and C18:1) were hardly affected by dietary concentrations (Teye et al., 2006). The traditional Spanish Iberico breed has a high gastronomic reputation due to its tender and juicy meat which is associated with rearing practices that include foraging on oleic acid-rich acorns (Daza et al., 2005). Overall, little is known about the efficiency of transfer of dietary C18:1 from C18:1-rich oils to fat and muscle tissues in pork.
High levels of PUFA are common in cereal-based pig commercial diets. While corn-soybean diets are widely used globally, in some geographical areas pig feed formulations might be based on other locally available grains and pulses mainly wheat, barley, sorghum, lupins or canola to mention only a few (Boye et al., 2010, Sevillano et al., 20182018). Little has been reported on how specific cereals and pulses may impact the amount and composition of fat deposits in pork.
The aim of this study was to produce pork with a distinctively pleasant bouquet signature associated with a high C18:1 content transferred from feed. In particular, the study assessed the impact of high dietary C18:1 in pigs on C18:1 in pork longissimus dorsi (LD) using three different feed formulations representing standard Australian, European, or North American feeds and two oils selected based on high (macadamia) or low (corn) C18:1 content. In addition, the project studied the impact of high C18:1 levels in pork on the physicochemical characteristics of the meat and on the sensory attributes of the roasted pork, with especial attention to potential differences in taste preferences with Chinese-background consumers, the main non-Western ethnic community in Australia.
It was hypothesized that C18:1-rich feeds would result in increased C18:1 levels in pork LD improving the hedonic value perceived by consumers across feed formulations relevant to Australia, Europe and North America. In addition, it was hypothesized that the improved hedonic value related to C18:1 will be independent of ethnic background.
Section snippets
Diets and animals
Three isoenergetic and isonitrogenous diets (14.1 MJ/kg and 17.4% CP) were formulated based on current standard diets used in Australia, Europe, and North America. A diet based on corn (cereal) and soybean meal (pulse) was chosen as representative of diets used in North America. A diet based on wheat and canola oil was chosen as likely to be used in parts of Europe (and potentially Western Australia). Finally, a diet with sorghum and lupins aimed to represent a uniquely Australian formulation.
Results and discussion
Future trends in pork market are heavily influenced by consumer demands towards healthier, safer, and better-quality meat (Yang & Lien, 2016). Pork eating quality has been associated with tenderness and flavor (Dunshea et al., 2005). An iconic pork flavor for succulence has been referred to as the Spanish Iberico breed typical of Western Spain (Ventanas et al., 2007). Compared to more prevalent commercial crossbreeds, the traditional Iberico shows slower growth rates associated with unique
Conclusions
Our study provides evidence that dietary C18:1-rich oils have the potential to manipulate fat profiles by increasing C18:1 in pork LD and produce a flavor signature of a high pleasing standard. The results provided valuable insight regarding the complexity of producing a high C18:1 meat profile in pigs. In particular, the interaction between oil sources (e.g. macadamia or corn oil in this project) and the main dietary ingredients (cereals and pulses) are key aspects to take into account that
CRediT authorship contribution statement
Marta Navarro: Investigation, Data curation, Methodology, Project administration, Writing - original draft, Writing - review & editing. Frank R. Dunshea: Conceptualization, Methodology, Writing - review & editing. Allan Lisle: Data curation, Formal analysis, Writing - review & editing. Eugeni Roura: Funding acquisition, Conceptualization, Methodology, Investigation, Writing - original draft, Writing - review & editing.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
The research was funded in part by the Australian Pork Limited. The authors would like to thank Dr. Heather Smith, Louis Dany, Nuria Elias and Jia Wen for their contribution to the sensory lab tests.
The authors acknowledge the contribution of Dr Darryl D’Souza, Robert Hewitt and Andres Corso and the Animal Ethics Committee of SunPork Solutions in the development of the animal experiment.
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