Novel and Conventional Steam Blanching Impacts on Potato Starch Digestibility and Physicochemical Properties

Abstract

Blanching plays a critical role in food production, and it is imperative to explore innovative techniques to overcome the limitations associated with conventional blanching methods. This study investigates the application of vacuum-steam pulse blanching (VSPB), an emerging technology, in the blanching of potatoes, comparing it to traditional steam blanching (SB). The evaluation was based on the potatoes’ browning enzyme inactivation, total phenols, antioxidation activity, starch digestibility, gelatinization degrees, and structural characteristics. The thermal and morphological analyses revealed that the blanching duration required for the browning enzyme inactivation totally gelatinized the potato starches. Prolonged blanching, whether using VSPB (with extended steaming cycles or lower vacuum pressure) or SB (for 180 seconds), decreased starch crystallinity and enhanced digestibility. VSPB effectively inactivated the browning enzyme while preserving total phenols and antioxidation activity in potatoes, yielding 39.14 mg GAE/100g fresh potato and 182.60 µmol TE/100 g fresh potato, respectively. In contrast, continuous steaming during SB for 60 s led to high enzyme activity, color difference, browning index, and FTIR absorption, reducing total phenols and antioxidant activity levels. Under optimum conditions (20 kPa vacuum pressure, three cycles, and 20 s steaming duration), VSPB increased the total phenol content and antioxidation activity, retained the potato structure and crystallinity, and recorded the lowest infrared absorbance level, providing an efficient scenario for potato blanching.