Effect of PEF on ginger roots: improving juice extraction yield or product quality

Description

This study investigated the combined effect of Pulsed Electric Field (PEF) treatment and (mild) heat treatment on the extraction yield and product quality of ginger roots. Treatments were compared to a thermal treatment (30 min 80°C) which is an industrial standard.
Fresh ginger roots were subjected to PEF treatment (E = 2 kV/cm, τ = 8 µs, w = 6 kJ/kg: 5/7 ginger-water ratio, w/w/) combined with different heat treatments (30 min 80°C, 2 min 90°C, 10 min 80°C, 10 min 50°C). After PEF treatment, 500 g of the ginger roots were processed, which includes an initial juicing step using a 1st angel juicer to separate pulp and juice. The separated pulp and juice were then recombined and heated. This mixture was processed again using a 2nd Angel juicer to further extract juice. Control samples without PEF treatment were also prepared for comparison. The juice yield was measured by weighing the extracted juice. Quality parameters such as dry matter, soluble solids, color, and the gingerol content were analyzed.
The results indicated that a combination of PEF with heat treatment (30 min 80°C) improves the extraction yield of juice with 3% compared to the control sample using only heat, while combinations of PEF and milder heat had the same extraction yield as the control. For both PEF treated and control samples, extensive heat treatments tend to darken the juice and reduce the yellow intensity, while combination of PEF with milder heat treatments retain the natural color.
Combination of PEF with heat can lead to interesting alternatives for conventional thermal treatment. Either one can add PEF to the current existing thermal treatment to increase juice extraction yield, while keeping the same quality. Alternatively, one can combine PEF with a milder heat treatment, leading to the same extraction yield as is the current standard practice, but with a better quality, and reduction of energy use.

Period	18 Sept 2024
Event title	World Conference on Electroporation & Pulsed Electric Fields in Biology, Medicine, Food and Environmental Technologies
Event type	Conference/symposium
Location	Rome, ItalyShow on map
Degree of Recognition	International