Effect of roasting degree of coffee beans on sensory evaluation: Research from the perspective of major chemical ingredients

As the most consumed beverage in the world, the material basis of the sensory quality for roasted coffee beans has always received much attention. The objective of the present study was to clarify the physical morphology changes, main chemical ingredients and cupping scores of arabica coffee beans of different roasting degrees, by scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) and sensory analysis, respectively. Statistical analysis of the data by multivariate analysis demonstrated that trigonelline, sugars, malate, quinic acids, gamma-butyro-lactone and acetate have the potential to be new roasting markers. Additionally, in all the sensory indicators, body and acidity were found to be susceptible to roasting degree. Basing on cluster heatmap and sensory molecular network, the complex relationships between sensory indicators and ingredients were discussed. The results of partial least squares regression (PLSR) showed that the content of the main coffee ingredients can be used to predict the body score.