Comparison of Cheese Aroma Intensity Measured Using an Electronic Nose (E-Nose) Non-Destructively with the Aroma Intensity Scores of a Sensory Evaluation: A Pilot Study

Abstract

Cheese aroma is known to affect consumer preference. One of the methods to measure cheese aroma is the use of an electronic nose (e-nose), which has been used to classify cheese types, production areas, and cheese ages. However, few studies have directly compared the aroma intensity scores derived from sensory evaluations with the values of metal oxide semiconductor sensors that can easily measure the aroma intensity. This pilot study aimed to investigate the relationship between sensory evaluation scores and e-nose values with respect to cheese aroma. Five types of processed cheese (two types of normal processed cheese, one type containing aged cheese, and two types containing blue cheese), and one type of natural cheese were used as samples. The sensor values obtained using the electronic nose, which measured sample aroma non-destructively, and five sensory evaluation scores related to aroma (aroma intensity before intake, during mastication, and after swallowing; taste intensity during mastication; and remaining flavor after swallowing (lasting flavor)) determined by six panelists, were compared. The e-nose values of many of the tested cheese types were significantly different, whereas the sensory scores of the one or two types of processed cheese containing blue cheese and those of the natural cheese were significantly different. Significant correlations were observed between the means of e-nose values and the medians of aroma intensity scores derived from the sensory evaluation testing before intake, during mastication, and after swallowing. In particular, the aroma intensity score during mastication was found to have a linear relationship with the e-nose values (Pearson's R = 0.983). In conclusion, the e-nose values correlated with the sensory scores with respect to cheese aroma intensity and could be helpful in predicting them.

Keywords: aroma; cheese; electronic nose (e-nose); non-destruction; sensory evaluation.

Figure 1

Electronic nose for sample bottom aroma: (a) measurement of a cheese sample; (b) diagram of the electronic nose.

Figure 2

Diagram of sensory evaluation for cheese aroma intensity scores and related scores.

Figure 3

Aroma intensity scores and related sensory scores of the 6 cheese samples in sensory scores (Median).

Figure 4

Comparison of aroma intensity scores and related sensory scores for 6 cheeses: (a) Before_Aroma; (b) Mastication_Aroma; (c) After_Aroma; (d) Mastication_Taste; (e) Lasting_Flavor.

Figure 5

Electronic nose sensor values for 6 cheeses (n = 3). The Tukey HSD test (a), and paired t-test (b), were used for comparison (*: p < 0.05; §: p < 0.005). Error bar: standard deviation. (a) Sensor values of cheese samples (30 min); (b) comparison of placement time between 30 and 90 min at room temperature.

Figure 6

Correlation of electronic nose sensor values (mean values in Figure 5a) and sensory scores (median values in Figure 4). R: Pearson’s correlation coefficient. Rs: Spearman’s rank correlation coefficient. (a) Before_Aroma; (b) Mastication_Aroma; (c) After_Aroma; (d) Mastication_Taste; (e) Lasting_Flavor.