Effects of high pressure processing on cocoyam, Peruvian carrot, and sweet potato: Changes in microstructure, physical characteristics, starch, and drying rate

Abstract

Abstract This study investigated the effect of high pressure processing (HPP) at 600 MPa for 5 and 30 min on cocoyam, Peruvian carrot, and sweet potatoes cylinders. The impact of the process was evaluated through syneresis analysis, water activity, polarized optical microscopy, thermal properties, texture profile, and drying rate. The results demonstrated that regardless of the process time, the HPP caused physical damage to the structure of the vegetables, providing greater syneresis (up to 12%), disruption of cell wall, reduction of the maximum force to cut the sample (up to 60%), and increased drying rate (~ 30%). Starch gelatinization ranged between 30% (in Peruvian carrot) and 70% (in sweet potato). Additionally, this process reduced the gelatinization temperature of the sweet potatoes starch. Therefore, the results suggest that HPP modifies the tubers structure, being an alternative for tubers softening and reduces the time required in its drying process. Industrial Relevance The results showed that HPP processing at 600 MPa for 5 or 30 min can be used as an interesting tool for pretreatment of dry tubers, increasing its drying rate and consequently reducing its process time. Additionally, the changes caused by the HPP process promote softening and pre-gelatinization of tubers starch, making them easier to be cooked by the final consumers.