Probing the combined impact of pulsed electric field and ultra‐sonication on the quality of spinach juice

Abstract

This study aimed to investigate the combined effects of ultrasound (US) and pulsed electric field (PEF) treatment on spinach juice. The spinach juice was sonicated at a frequency of 40 kHz, radiating power 200 W, and temperature 30°C for 21 min in an ultrasonic bath, followed by PEF treatment (pulse frequency: 1 kHz, flow rate: 60 ml/min, temperature: 30°C, time: 335 µs, and electric field strength 9 kV/cm). The combined treatment (US-PEF) has achieved the highest value of flavonoids, phenolic, flavonols, anthocyanin, carotenoids, total chlorophyll, vitamin C, DPPH, and total antioxidant capacity than single treatments of US and PEF as well as untreated sample. The inactivation of peroxidase and polyphenol oxidase was increased during US-PEF treatment from 0.85 and 0.025 Abs/min (untreated) to 0.18 and 0.011 Abs/min, respectively. There was a slightly visible variation in color values among all the treatments. Practical applications Nowadays, novel processing techniques, are employed to improve the nutritional quality and stability of juices. The consequences of the present research showed that combined treatment (US-PEF) could improve the TPC, TFC, total flavonols, antioxidant activities, chlorophyll, carotenoids, vitamin C, and anthocyanins content while reducing the activity of the enzyme. The verdicts described that US-PEF can enhance the quality of spinach juice at an industrial scale.