Plasma frio como tecnologia de modulação química: avaliação dos perfis volátil e fenólico do suco de abacaxi

Abstract

Cold plasma is an innovative technology with potential to selectively modulate chemical compounds in foods, enhancing both sensory and nutritional properties. This study aimed to evaluate the effects of two types of cold plasma—dielectric barrier discharge (DBD) and glow discharge (GD)—on the volatile and phenolic composition of pineapple juice (Ananas comosus), as well as their sensory impacts on juice aroma. DBD plasma was applied at excitation frequencies of 50, 500, and 1000 Hz for 10 and 20 min, while GD plasma was conducted at varying gas flow rates of 10, 20, and 30 mL/min for 20 min. Volatile composition analysis, performed via GC-MS, revealed that plasma treatment primarily promoted successive demethylation of long-chain esters and the conversion of methyl esters into ethyl esters. These chemical modifications improved fresh and fruity sensory notes and reduced the pungently sweet aroma of methyl hexanoate, particularly under the conditions DBD at 50 Hz/10 min, DBD at 500 Hz/10 and 20 min, and GD at 20 mL/min for 10 and 20 min, maintaining an acceptable balance between freshness and sulfurous notes. Regarding the phenolic profile, eleven compounds were identified by GC-MS, with syringic acid being the most abundant. Both plasma treatments resulted in significant changes to these phenolic compounds, notably increasing syringic acid concentrations and significantly reducing vanillic acid levels, especially under DBD at 500 Hz and GD at 20 mL/min, indicating activation of the phenylpropanoid pathway and selectivity of the involved enzymes depending on processing conditions. Structural changes in benzoic acid derivatives suggested specific reactions such as methyl group abstraction induced by plasma-generated reactive species. These findings reinforce that cold plasma, when optimally adjusted, can enhance the volatile and phenolic profiles of pineapple juice, improving its sensory and nutritional properties. Such capabilities pave the way for its application in functional beverages tailored to consumer sensory preferences and nutritional demands.