Changes on phenolic and carotenoid composition of high intensity pulsed electric field and thermally treated fruit juice-soymilk beverages during refrigerated storage

Abstract

The effects of high intensity pulsed electric fields (HIPEF) (35kV/cm with 4μs bipolar pulses at 200Hz for 800 or 1400μs) or thermal (90°C, 60s) treatments over phenolic and carotenoid compounds of a fruit juice-soymilk (FJ-SM) beverage stored at 4°C were evaluated and compared, having the untreated beverage as a reference. Coumaric acid, narirutin and hesperidin were the most abundant phenolic compounds in the FJ-SM beverage, while the main carotenoids were lutein, zeaxanthin and β-carotene. Immediately after HIPEF or heat processing, hesperidin content of the beverage showed a huge rise, resulting in a significant increase on the total phenolic concentration. Regarding carotenoid concentration, HIPEF or thermal treatment lead to a significant decrease; lutein, zeaxanthin and β-cryptoxanthin being the most affected compounds. In contrast, the content of some individual phenolics and carotenoids increased with time, while others tended to decrease or remained with no significant changes with regards to their initial values. Total phenolic concentration seemed to be highly stable during storage; while, total carotenoid content gradually diminished, irrespectively of the treatment applied. Overall, the changes observed in HIPEF treated FJ-SM beverage were less than those in the heat processed one. Hence, HIPEF is a feasible technology to obtain FJ-SM beverages with extended shelf-life and a similar profile of antioxidant compounds to freshly made beverages.

Keywords: Carotenoid compounds; Fruit juice–soymilk beverages; High intensity pulsed electric fields; Phenolic compounds.