EFFECTS OF HIGH INTENSITY PULSED ELECTRIC FIELDS OR THERMAL PASTEURIZATION AND REFRIGERATED STORAGE ON ANTIOXIDANT COMPOUNDS OF FRUIT JUICE-MILK BEVERAGES. PART I: PHENOLIC ACIDS AND FLAVONOIDS

摘要

The effects of high intensity pulsed electric fields (HIPEF) or thermal pasteurization (TP) over phenolic compounds in mixed beverages were evaluated after processing and during chilled storage, having untreated beverage as reference. Total phenolic (TPC, 57.0-58.8mg of galic acid/100mL) and flavonoid (TFC, 4.14-4.33mg of quercetin/100mL) contents remained constant in fruit juice-skim milk (FJ-SM) and -whole milk (FJ-WM) beverages just after HIPEF or TP. Nonetheless, concentration of most individual phenolics augmented. TPC in HIPEF treated beverages remained constant through storage, while in thermally pasteurized beverages tended to decrease (5-15%). No significant changes were observed in TFC in untreated and treated beverages over time. The concentration of individual phenolics in fresh and treated beverages remained constant or decrease with time, except hesperidin, which significantly increased (19-61%) after 56 days. Hence, HIPEF is a feasible technology to obtain mixed beverages with antioxidant properties.