Effect of Superchilling Combined with Modified Atmosphere Packaging on Quality Indicators of Truffle and Correlation among Them as Analyzed by Principal Component Analysis

Objective: To investigate the effect of superchilling combined with modified atmosphere packaging (MAP) on the quality indicators of truffle during storage. Methods: Truffle samples were stored at −(4.4 ± 0.2) ℃ under normal atmosphere (control) and 40% O2 + 60% CO2 atmosphere (group A), and quality changes during storage were determined. Discriminant models were established using principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). Results: Each quality index showed different trends under the two different storage atmospheres. Truffle was preserved significantly better in group A than the control group; the water loss and decay rate were effectively reduced in group A. On the 20th day of storage, the moisture content, decay rate and mass loss rate of group A were 63.62%, 6.94% and 1.02%, respectively; moisture content was significantly higher than control group (P < 0.05), and decay rate and mass loss rate were lower than control group, respectively (P < 0.05). Truffle quality was maintained better in group A than the control group, in terms of maintaining textural characteristics such as hardness and elasticity and delaying the decline in the contents of polysaccharides, total polyphenols, total flavonoids and crude protein and ferric ion reducing power. After 20 days of storage, the contents of polysaccharides, total polyphenols, total flavonoids and crude protein, and ferric ion reducing power were reduced by 27.94%, 32.51%, 16.18%, 68.58%, and 18.13%, respectively, which were lower than those in the control group. Correlation analysis and the developed discriminant models could effectively distinguish the quality differences of the samples under different treatments, indicating that physicochemical indexes influenced the quality of truffle during the storage period. OPLS-DA could also effectively differentiate the components of the truffle samples under different treatments. Conclusion: Superchilling combined with MAP can better preserve fresh truffle, and this study provides a theoretical basis for the development of new truffle preservation technologies.