*Article* **Gas Chromatography–Mass Spectrometry-Based Metabolomic Analysis of Wagyu and Holstein Beef**

#### **Tomoya Yamada \*, Mituru Kamiya and Mikito Higuchi**

Division of Livestock Feeding and Management, National Agriculture and Food Research Organization, Nasushiobara, Tochigi 329-2793, Japan; m\_kamiya@affrc.go.jp (M.K.); mikito@affrc.go.jp (M.H.)

**\*** Correspondence: toyamada@affrc.go.jp; Tel.: +81-287-37-7811

Received: 6 February 2020; Accepted: 5 March 2020; Published: 6 March 2020

**Abstract:** Japanese Black cattle (Wagyu) beef is characterized by high intramuscular fat content and has a characteristic sweet taste. However, the chemical components for characterizing the sweet taste of Wagyu beef have been unclear. In this experiment, we conducted a metabolomic analysis of the longissimus muscle (sirloin) in Wagyu and Holstein cattle to determine the key components associated with beef taste using gas chromatography–mass spectrometry (GC-MS). Holstein sirloin beef was characterized by the abundance of components such as glutamine, ribose-5-phosphate, uric acid, inosine monophosphate, 5-oxoproline, and glycine. In contrast, Wagyu sirloin beef was characterized by the abundance of sugar components (maltose and xylitol). Dietary fat is known to increase the intensity of sweet taste. These results sugges<sup>t</sup> that the sweet taste of Wagyu beef is due to the synergetic effects of higher sugar components and intramuscular fat.

**Keywords:** metabolome; beef; Wagyu; Holstein
