One issue surrounding the use of the SQI is that it is a ratio between two scores obtained with an interval scale (9-point hedonic
scale). Generally, interval scale data assume that there is an equal
distance between the points on the scale (Stone & Sidel, 1993).
Since interval scales do not have a true or rational zero point, a ratio between the scores have not yet been used as an index or a factor with sensory evaluation data. It was assumed that there would
be a linear relationship between the difference of a sample’s scores
measured by the 9-point hedonic scale and the SQI, which is a ratio
of the acceptability scores measured by the 9-point hedonic scale if
the ratio calculated by interval scale data is a suitable factor. Table
2 and Fig. 1 shows the strong positive correlation between the SQI
and the difference of acceptability scores (r = 0.997, p < 0.001).
Thus, the SQI might be a useful as a sensory quality hurdle.