Exploring the Lipids Involved in the Formation of Characteristic Lactones in Japanese Black Cattle.

Shuji Ueda,Rio Nakabayashi,Eiji Iwamoto,Minoru Yamanoue,Yasuhito Sirai,Ryo Sasaki

doi:10.3390/metabo11040203

Abstract

The meat from Japanese Black cattle (Japanese Wagyu) is finely marbled and exhibits a rich and sweet aroma known as Wagyu beef aroma. To clarify the key metabolites involved in the aroma, we analyzed the correlation between lactone and lipid composition in Japanese Black cattle. Using gas chromatography-olfactometry, we identified 39 characteristic odorants of the intermuscular fat. Seven characteristic lactones considered to be involved in Wagyu beef aroma were quantified and compared in the marbled area and intermuscular fat using a stable isotope dilution assay. Among them, γ-hexalactone was the only lactone whose level was significantly higher in the marbled area. To explore the lipid species involved in lactone formation, we analyzed samples with different aroma characteristics. Liquid chromatography-mass spectrometry revealed eight lipid classes and showed significant differences in triacylglycerides (TAGs). To determine the molecular species of TAGs, we performed high-performance liquid chromatography analysis and identified 14 TAG species. However, these analyses showed that seven lactones had a low correlation with the TAGs. However, γ-hexalactone showed a positive correlation with linoleic acid. This study suggests that lipid composition affects the characteristic lactone profile involved in the Wagyu beef aroma.

Highlights

Japanese Black cattle, known as Japanese Wagyu, are used to produce one of the world’s most renowned types of beef [1]
Holstein cattle, which are mostly characterized by lean meat, are often used experimentally in comparisons with Japanese Black cattle, as their proportions of intramuscular fat [4], which is responsible for marbling in the muscles, differ significantly
We aim to investigate the relationship between lipid composition and Wagyu beef aroma using intermuscular fat and marbled area of steak to clarify the key metabolites contributing to Wagyu beef aroma development

Summary

Introduction

Japanese Black cattle, known as Japanese Wagyu, are used to produce one of the world’s most renowned types of beef [1]. Its defining characteristics are the excellent marbling of crossed fat in muscle tissues and its rich and sweet aroma (the so-called Wagyu beef aroma). There are two types of lactones produced during beef cooking, namely, γ-lactone and δ-lactone, and they have different heterocyclic carbon atoms. Holstein cattle, which are mostly characterized by lean meat, are often used experimentally in comparisons with Japanese Black cattle, as their proportions of intramuscular fat [4], which is responsible for marbling in the muscles, differ significantly. As the characteristic lipid metabolism of Japanese Black cattle has a significant influence on meat quality (tenderness, flavor, and juiciness) [6,7], there are several studies on genes which are crucial for the marbling trait [8,9,10,11]. Studies have attempted to analyze the aroma of Wagyu beef [12,13,14]

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