Abstract:

The aim of this study was to assess the feasibility of using near infrared spectroscopy (NIRS) to rapidly determine three textural properties of goat yoghurt: firmness, cohesiveness and water holding capacity. Forty five goat yoghurt samples fermented by different strains under different process conditions were subjected to near infrared spectral analysis, and their spectra were resolved, and based on pre-processing by second derivative (SD) method, prediction models for firmness, cohesiveness and water holding capacity were developed with partial least square (PLS), with determination coefficients (R2) of 0.6668, 0.6461and 0.7269, respectively. The correlation coefficient of external-validation for 12 goat yoghurt samples was 0.7577 for firmness, 0.7200 for cohesiveness and 0.7174 for water holding capacity. No significant difference was found in t tests between the predicted and experimental values of these three parameters (P＞ 0.05). The above results show that NIRS is applicable to assess the textural properties of goat yoghurt with good accuracy. However, further studies on statistical modeling need to be done for improving prediction precision.

Key words: goat yoghurt, near infrared spectroscopy, textural property, partial least squares