Evaluation of quality parameters of orange juice stabilized by two thermal treatments (helical heat exchanger and ohmic heating) and non-thermal (high-pressure processing)

This work aims to compare the impact of three thermal (helical coil heat exchanger HCHE, ohmic heating OH, and mild pasteurization MP) and one non-thermal (high-pressure processing HPP) treatments on orange juice by using industrial plants. Nutritional (total phenolic content (TPC), ascorbic acid (AA) and total antioxidant capacity (TAC)), physical (viscosity, colour, browning index (BI) and suspended pulp (SP)), sensory (Triangle test and QDA) as well as chemical (H-1 NMR spectroscopy) aspects were analyzed. Results revealed a significant (p < 0.05) increase in viscosity for HPP (+20%) compared to untreated samples while the opposite effect was observed for all thermal treatments (-22%). The lowest a* values were observed in HPP and HCHE samples. Total phenolic content decreased significantly only in HCHE (-14%), while the highest ascorbic acid content was observed in HPP samples and it resulted not significantly different from untreated. Regarding the chemical profile, treated samples (except for MP) led to a significant (p < 0.05) decrease of all selected marker peaks, mainly including sugars (alpha- and beta-glucose, beta-fructose, and sucrose) and amino acids compared to untreated ones. HPP samples showed a similar sensory profile if compared with the untreated sample, showing only a significant difference (p < 0.05) in terms of orange aroma; on the contrary, OH, HCHE, MP rated the lowest acceptances due to, among all considered descriptors, orange aroma, cooked aroma, sweetness, cooked taste.