Effect of pulsed electric field and thermal treatments on the bioactive compounds, enzymes, microbial, and physical stability of almond milk during storage

Abstract

This study was designed to examine the impact of thermal treatment (TT) and pulsed electric field (PEF) on the overall quality of almond milk. The storage study showed a reduction in bioactive compounds and antioxidant activities with periods, while PEF-treated almond milk exhibited a higher amount than untreated and TT samples. PEF and TT improved the product microbial shelf-life during storage. Lipoxygenase and peroxidase of the PEF-treated sample at 28 kV/cm were inactivated by 50% and 45%, respectively; whereas TT achieved 59% and 68%, respectively. The less color variation was observed in PEF-treated samples than TT. The colloidal stability was significantly increased as a result of particle size and sedimentation index reduction after the PEF treatment. Results showed an increase in free amino acid production with increasing after PEF processing, while the fatty acids profile did not change significantly. Furthermore, the processing treatments did not significantly change the pH, soluble solids, and acidity values. Practical applications Nowadays, different non-thermal techniques are used to enhance the nutritional quality and stability of different fruits and vegetable juices. The present research showed that pulsed electric field (PEF) could enhance the bioactive compounds, antioxidant activities, colloidal stability, and free amino acid, while reducing the activity of the enzyme and microbial load. The results of this research proposed that the PEF can enhance the quality of almond milk and may be applied at an industrial scale.