Abstract

The main aim of the current investigation was to contemplate the impact of high-voltage electric field cold plasma (HVCP) on different quality characteristics (enzymes, microbial activities, coloring pigments, ascorbic acid, polyphenolic compounds, °Brix, acidity, and color index) of carrot juice in correlation with thermal processing. A carrot juice (250 mL) sample sealed in pre-sterilized food-grade bottles, which placed between two dielectric quartz plates for HVCP treatment. The gap between the plates was 30 mm, and a stable and uniform plasma dielectric barrier discharge (DBD) generated for 3 and 4 min at 60, 70, and 80 kV. Air was used as a working gas during the DBD-based plasma treatment. The observed rise in temperature was 2–5 °C during the HVCP treatment. A water bath was used to carry out thermal treatment (100 °C for 5 min). The maximum inactivation of enzymes and microorganisms was achieved with thermal treatment and then with HVCP treatment at 70 kV for 4 min. However, maximum retention of coloring compounds, ascorbic acid, total phenols, flavonoids, and tannins was found following HVCP (70 kV for 4 min) treatment compared to thermal treatment. The °Brix, pH, and acidity remained unchanged irrespective of treatments. These findings suggest that HVCP treatment at 70 kV for 4 min may be a good alternative to thermal treatment, and it may successfully be applied in carrot juice production, resulting in reduced enzymes, lower microbial activity, and improved bioactive compounds. The prospects of overcoming the existing conventional physical and chemical methods for sterilization make it a novel and more economical technique to maintain food’s natural nourishment, composition, appearance, structure, and freshness.

Highlights

  • The carrot (Daucus carota L.) is an important root vegetable with a pleasant taste, high nutritional value, and several benefits to human health due to its specific anti-anemic, anticancer, antioxidant, Antibiotics 2019, 8, 235; doi:10.3390/antibiotics8040235 www.mdpi.com/journal/antibioticsAntibiotics 2019, 8, 235 sedative, and healing characteristics [1]

  • The results indicated that thermal processing (TP) treatment has significantly improved the color values (L*, a*, and b*) of carrot juice

  • high-voltage electric field cold plasma (HVCP) processing processing has has the the potential potential for for improving improving The the quality and safety of carrot juice, and it may successfully be employed in beverage industries

Read more

Summary

Introduction

The carrot (Daucus carota L.) is an important root vegetable with a pleasant taste, high nutritional value, and several benefits to human health due to its specific anti-anemic, anticancer, antioxidant, Antibiotics 2019, 8, 235; doi:10.3390/antibiotics8040235 www.mdpi.com/journal/antibiotics. Enzymes can be involved in the deterioration of food products that cause undesirable color, flavor, or nutritional changes [4] These enzymes include peroxidase (POD), pectin-methylesterase (PME), polyphenol-oxidases (PPO), and lipoxygenase (LOX). The shelf life of vegetable juices improved by the inactivation of the enzymes and microorganisms through heat treatments [6] These thermal treatments often cause adverse changes in the food products that account for color alterations, loss of nutrients, and off-flavor development [7]. The influence of the plasma used to sterilize large-scale liquid foods on the quality of fruit juices needs to be evaluated; it is important to study the effect on color changes during HVCP treatment. As consumers are more conscious about health and diet, and their demand for fresh food brought about increased interest in the mild processing technologies used

Chemicals
Peroxidase Enzyme Residual Activity
Polyphenol Oxidase Enzyme Residual Activity
Pectin Methylesterase Enzyme Residual Activity
Determination of Lipoxygenase Residual Activity
Determination of Total Carotenoids
Determination of Lycopene Contents
Determination of β-carotene and Lutein
Determination of Chlorogenic Acid
Determination of Sugar Content in Carrot Juice
Determination of Mineral Contents
Total Phenolic Content
Total Flavonoid Contents
Total Tannin Contents
Determination of pH in Carrot Juice
Determination of Titratable Acidity
Determination of Color Changes in Carrot Juice
Determination of Ascorbic Acid
Microbiological Analysis
2.10. Statistical Analysis
Effect of HVCP on Enzyme Inactivation
Results
Effect of HVCP on Lycopene and Lutein Contents
Determination of Sugars Content in Processed Carrot Juice
Impact
Effect of HVCP on Ascorbic Acid of Carrot Juice
Effect of HVCP Treatment on Phenolic Compounds
Antimicrobial Activity Assay
Conclusions

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.