Abstract: X-ray computed tomography (CT) was used to explore texture characteristics of semi-sweet hard biscuit, and the correlations between physical properties and CT index were also evaluated. The results showed that the internal texture of the biscuits could be distinctly observed two-dimensionally and three-dimensionally by means of CT reconstruction. CT indexes (CT density, porosity, and average cross-sectional area of bubbles) exhibited significant correlations (R > 0.9, P < 0.05) with protease dosage, sodium metabisulfite (SMS) concentration and biscuit physical properties (thickness and apparent density), indicating that biscuit texture variations with protease or SMS could be quantitatively determined by CT method. When similar reductions in gluten strength were applied to the biscuit dough by protease and SMS, significant differences were found in biscuit physical properties and CT indexes between two kinds of biscuits (P < 0.05) as well as in distribution patterns of average cross-sectional area of bubbles, suggesting that biscuit texture variations with reducing gluten strength by different methods could also be measured by CT method. Therefore, CT method is effective in qualitatively and quantitatively testing biscuit texture, providing valuable information for biscuit production and research.

Key words: X-ray computed tomography (CT), semi-sweet hard biscuit, texture, protease, sodium metabisulfite