High intensity pulsed electric fields or thermal treatments effects on the amino acid profile of a fruit juice-soymilk beverage during refrigeration storage

Resumen

This paper aims to evaluate the effects of high intensity pulsed electric fields (HIPEF) (35 kV/cm with 4 μs bipolar pulses at 200 Hz for 800 and 1400 μs) or thermal pasteurization (90°C for 60 s), on the free amino acid (AA) profile of a fruit juice-soymilk (FJ-SM) beverage stored at 4°C. The free AA profile of the FJ-SM beverage was constituted by Arg, Pro, Glu, Asp and Ala, as the most abundant AAs, and Ser, Phe, Leu, Lys, Thr, Tyr, Met, Val, Gly, Hys and Ile in lower concentrations. Immediately after HIPEF-800 μs process no significant changes on individual free AA content of the FJ-SM beverage were observed, except for Val concentration which increased. Conversely, when HIPEF-1400 μs or heat treatments were applied, Glu, Gly, Tyr, Val, Leu, Phe, Lys and Ile content was significantly reduced, while the concentration of Arg, Ala and Met slightly increased. Hence, total free AA content of HIPEF-800 μs treated FJ-SM beverage was similar to that of the untreated one (64.5-64.79 mg/100 mL), whereas those HIPEF-1400 μs or heat treated beverages presented lower values (60.25-61.82 mg/100 mL). Regardless of the treatment applied, the concentration of most individual free AAs, as well as total content, significantly increased along the storage; although, Pro content diminished with time. Additionally, His, Tyr, Met and Leu content of thermally treated beverages decreased as storage time increased. Overall, HIPEF treated FJ-SM beverages had higher free AA content than those thermally processed. Hence, free AA composition of mixed beverages could be well retained after applying HIPEF processes. Industrial relevance: HIPEF process is a potential technology in order to obtain mixed beverages with similar content of health-related compounds than fresh products. The FJ-SM beverage evaluated in this study represents a good source of almost essential AA recommended for good health. Food industry could apply this novel process to preserve liquid foods with high content of bioactive compounds and fresh-like characteristics, avoiding the detrimental effects caused by heat. © 2012 Elsevier Ltd.