Effect of Atmospheric Cold Plasma on the Aroma of Pineapple Juice: Improving Fresh and Fruity Notes and Reducing Undesired Pungent and Sulfurous Aromas

Abstract

Pineapple aroma is characterized by several esters, which confers its fresh and fruity aroma. However, high concentrations of methyl hexanoate and thioesters bring an undesired pungently sweet aroma and sulfurous notes to pineapple juice. This study investigates the chemical effects of cold plasma on the aroma compounds and descriptors of pineapple juice, evaluating the effects of plasma on its esters and thioesters. Dielectric barrier discharge plasma was applied to pineapple juice, varying the excitation frequency (50 to 1000 Hz) and processing time (10 to 20 min) at constant voltage (20 kV). Plasma treatment induced successive demethylation of esters and the conversion of methyl esters into ethyl esters. Thioesters showed to be more stable under plasma treatment. Proper setting of plasma operating conditions enabled an improvement in the fresh and fruity descriptors of pineapple juice, a reduction of its undesired pungently sweet aroma, but an increase in the influence of sulfurous descriptors. Plasma treatment at 50 Hz reduced the undesired aromas of pineapple while maintaining its fresh and fruity descriptors.

Influence of Cold Plasma Processing on the Stability of Phenolic Compounds of Araça-Boi (Eugenia stipitata) Juice

“…These observations sum up to those of other reports on araça-boi showing the benefits regarding cold plasma processing on aroma compounds, volatiles, sugars, and other organic acids [18]. Furthermore, this study has contributed to other studies on plasma application to fruit juices, showing that nutritional quality improvement is much higher than the few drawbacks of the technology, such as the decrease in amino acid content [13,28]. This work has not performed a stability test of the phenolics on the juices because that was not the focus of this study.…”

“…The plasma-treated araça-boi juice presented a small concentration of p-coumaric acid formed during the plasma treatment, since no p-coumaric acid was detected in the untreated juice. In the DBDP, the increase in p-coumaric acid occurred mainly under 50 and 500 Hz, conditions that generate the highest amounts of hydroxyl free radicals [28], which may be responsible for the hydrolysis of cinnamic acid into p-coumaric acid, following the reaction shown in Figure 1. The GDP treatment has formed p-coumaric acid, but only in the conditions employing 20 and 30 mL/min.…”

Chemical and physical changes induced by cold plasma treatment of foods: A critical review

“…The abstraction of methyl units occurred mainly with some esters with more than six carbons such as methyl hexanoate and methyl octanoate. Ethyl acetate, methyl butanoate, and methyl 2-methyl butanoate were increased during the process (Porto et al, 2023).…”

Effect of Low-Frequency High-Power Ultrasound Processing on the Volatile Compounds and Aroma Profile of Cashew Apple Juice

“…The samples were desorbed for 1 min directly in the injector, set at 250 °C, and separation was attained using an Equity-1 column (30 m × 0.25 mm ID × 0.25 μm film). Oven programming followed the method described by Porto et al 29 The relative intensity of each compound has been calculated as the ratio between the area of the specific molecule and the sum of the areas of all identified peaks (peak area normalization method) in the chromatogram. 30 The mass spectra were compared with the NIST and Wiley mass spectra library.…”