咀嚼能力が高く、咀嚼回数が多いほど、レトロナス性の香りが高まる

Higher Masticatory Performance and Higher Number of Chewing Strokes Increase Retronasal Aroma.

抄録

咀嚼は、食物を粉砕し、唾液と混ぜ合わせて飲み込むための生理的プロセスであり、食物から鼻の受容体に放出されるレトロナサール香の最初のプロセスでもあります。しかし、咀嚼の状態がレトロナサール香に与える影響については、あまり理解されていません。本研究の目的は、香りの濃度と咀嚼状態に関連する要因との関係を調べることです。研究デザインは、分析的観察研究とした。男性ボランティア12名（年齢、26.5±2.7歳）を募集し、咀嚼能力が低い群と高い群にそれぞれ5名と7名に分けました。参加者がパラフィンワックスを咀嚼している間の刺激唾液流量を測定した。まず，鼻孔に匂いセンサーを装着し，咀嚼能力評価用に標準化されたオレンジ味のグミゼリーを飲み込むまで噛んでいる間の香りの濃度を経時的に測定し，咀嚼ストロークをカウントして飲み込みの閾値を決定した。咀嚼回数をカウントして嚥下閾値とした後、一定回数（嚥下閾値の50％、100％、30回）の咀嚼を行い、嚥下せずにゼリーを吐き出すように指示した。30回の咀嚼時に粉砕されたゼリーの表面積を咀嚼能力とした。咀嚼能力の低い群と高い群で，香りの濃度，表面積，咀嚼ストローク数，刺激唾液流量の最大値と傾きを比較した．統計的有意性はα=0.05とした。30回の咀嚼ストロークで、最大香気濃度と傾きは、高咀嚼能力群が低咀嚼能力群よりも有意に大きかった。両群とも、最大香気濃度と香気放出を伴う咀嚼ストローク数との間に正の相関が認められた。最大香り濃度と刺激唾液流量の間には有意な相関は見られなかった。しかし，香りの濃度を従属変数とした重回帰分析では，表面積の増加，咀嚼ストローク数，刺激唾液流量が有意な説明変数であることが示された。この結果から、レトロナスの香りは咀嚼状態と咀嚼時の唾液流量に影響されることが示唆されました。

Mastication is a physiological process whereby food is comminuted and mixed with saliva to form a swallowable bolus; it is also the initial process for retronasal aroma that is released from foods to receptors in the nose. However, the influence of mastication state on retronasal aroma is poorly understood. The purpose of this study was to investigate the relationship between aroma concentration and factors related to mastication state. The study design was an analytical observational study. Twelve male volunteers (age, 26.5 ± 2.7 years) were recruited and divided into five and seven participants in the low and high masticatory performance groups, respectively. The stimulated salivary flow rate was measured while participants chewed paraffin wax. First, an odor sensor was placed in the nostril, and the aroma concentration was measured over time as participants chewed an orange-flavored gummy jelly standardized for masticatory performance assessment until swallowing; chewing strokes were counted to determine swallowing thresholds. Next, participants were instructed to chew the gummy jelly for a certain number of strokes (i.e., 50 or 100% of swallowing thresholds, as well as 30 strokes) and expectorate the jelly without swallowing. The surface area of comminuted jelly at 30 chewing strokes was defined as masticatory performance. Maximum and slope of aroma concentration, surface area, number of chewing strokes, and stimulated salivary flow rate were compared between low and high masticatory performance groups. Statistical significance was set at α = 0.05. At 30 chewing strokes, the maximum aroma concentration and the slope were significantly greater in the high masticatory performance group than in the low masticatory performance group. There was a positive correlation between the maximum aroma concentration and the number of chewing strokes with aroma release in both groups. No significant correlation was found between the maximum aroma concentration and the stimulated salivary flow rate. However, multiple regression analysis (with aroma concentration as a dependent variable) showed that the increase in surface area, the number of chewing strokes, and the stimulated salivary flow rate were significant explanatory variables. The results suggested that retronasal aroma was influenced by mastication state and salivary flow rate during chewing.