The aim of this study was to evaluate the effect of hot air drying, freeze drying and swell drying (which is a coupling of hot air drying to instant controlled pressure drop DIC) on strawberry to compare and contrast its quality in terms of texture, such as crunchy and crispy features, correlated with the expansion ratios and the microstructure's modification. The obtained results showed that swell-dried strawberry had a high crispness behavior. Also, its relative expansion ratio was thrice more than air-dried samples. Moreover, it was observed that saturated steam pressure of DIC texturing operation compared with the thermal holding time had a significant effect on the maximum penetration distance and the average of microruptures force on crunchiness and crispness, respectively. Hence, these structural changes provide a versatile swell-dried strawberry as highly functional snack that was able to be evaluated instrumentally by puncture test.

Hot air drying (HAD), freeze-drying (FD), and swell-drying (SD, coupling instant controlled pressure drop, DIC, to standard hot air) were applied to strawberries (Fragaria var. Camarosa). The total phenol, total flavonoid, and total anthocyanin contentswere evaluated versusthe drying methods. The correlations between the bioactive compounds and antioxidant activity were investigated. The obtained results showed that the differences in phenol levels were no quite comparing the three drying techniques; however, great variations were reported for anthocyanin and flavonoid content.A strong correlation between the antioxidant activity and anthocyanin content was found in SD strawberries. Also, it was observed that saturated steam pressure (P) of DIC texturing operation, had a significant effect on the studied parameters compared to the thermal holding time (t). The optimum conditions of DIC were P = 0.35 MPa for t = 10 s to obtain the highest levels of phenols, flavonoids, and anthocyanins, as well as antioxidant activity.