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Clinical Trial
. 2021 Jan 22;26(3):575.
doi: 10.3390/molecules26030575.

Subjective Effects of Inhaling Kuromoji Tea Aroma

Eri Matsubara  1 , Takeshi Morikawa  1 , Norihisa Kusumoto  1 , Koh Hashida  1 , Naoyuki Matsui  1 , Tatsuro Ohira  1
Affiliations
Clinical Trial

Subjective Effects of Inhaling Kuromoji Tea Aroma

Eri Matsubara et al. Molecules. .

Abstract

Teas and various herbal teas are well-known beverages and are commonly consumed around the world. In this study, we focused on kuromoji tea. Kuromoji is a deciduous shrub of the Lauraceae family, and the plucked leaves and branches have been drunk as a tea in production areas for a long time. However, no studies have investigated the subjective and physiological effects of kuromoji tea. In this study, the effects of kuromoji tea were examined on the basis of the measurements of heart rate variability and cerebral blood flow, core body temperature and subjective assessments. Moreover, the results of this study showed that a pleasant subjective feeling could be obtained by sniffing the aroma of kuromoji teas, especially tea leaves. It was also found that the aroma of kuromoji teas has the potential to stimulate saliva secretion and increase subjective and physiological excitements in the oral cavity. 1,8-Cineole, linalool, terpinen-4-ol, carvone and geraniol were determined in both kuromoji leaves and branches. In this study, the beneficial effects of kuromoji teas when drunk conventionally were investigated.

Keywords: Japanese herbal tea; branches; kuromoji; leaves; subjective effects.

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Conflict of interest statement

The authors declare that they have no conflict of interest.

Figures

Figure 1
Figure 1
Subjective assessments of aroma for the experimental materials. Visual analog scale (VAS) scores in experiment 1 (A) and 2 (B) are shown. Irritation scores and hedonic scores in experiment 1 (C) and 2 (D) are also shown. Different letters represent statistically significant differences among experimental materials. Data are shown as means ± SEM.
Figure 1
Figure 1
Subjective assessments of aroma for the experimental materials. Visual analog scale (VAS) scores in experiment 1 (A) and 2 (B) are shown. Irritation scores and hedonic scores in experiment 1 (C) and 2 (D) are also shown. Different letters represent statistically significant differences among experimental materials. Data are shown as means ± SEM.
Figure 2
Figure 2
Headspace–solid-phase microextraction (HS-SPME)/gas chromatography–mass spectroscopy (GC–MS) chromatograms of the experimental materials used in this study. Numbers accompanying each peak indicate the peak number in Table 1.
Figure 3
Figure 3
Relationships between subjective feelings and physiological responses. Plots represent the relationships between the values of LF norm or oxyHb and the subjective assessments in experiment 1 (A) and 2 (B).
Figure 3
Figure 3
Relationships between subjective feelings and physiological responses. Plots represent the relationships between the values of LF norm or oxyHb and the subjective assessments in experiment 1 (A) and 2 (B).
Figure 4
Figure 4
Experimental procedure. Heart rate variability, oxygenated hemoglobin and core body temperature were continually measured before, during and after the experiment. Questionnaires for subjective assessments, the irritation scale, the hedonic scale and the VAS were administered immediately after sniffing or inhaling the aroma of the experimental materials. Abbreviations are as follows: HRV, heart rate variability; OxyHb, oxygenated hemoglobin; Temp, core body temperature; Sniff, sniffing; Inhale, inhaling; Ques, questionnaires; Expt.1, experiment 1; Expt.2, experiment 2.
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