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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Publications at this Location » Publication #406406

Research Project: New Sustainable Processes, Preservation Technologies, and Product Concepts for Specialty Crops and Their Co-Products

Location: Healthy Processed Foods Research

Title: Benefits of isochoric freezing for carrot juice preservation

item Bilbao-Sainz, Cristina
item Olsen, Carl
item Chiou, Bor-Sen
item RUBINSKY, BORIS - University Of California Berkeley
item Wu, Vivian
item McHugh, Tara

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2024
Publication Date: 2/5/2024
Citation: Bilbao-Sainz, C., Olsen, C.W., Chiou, B., Rubinsky, B., Wu, V.C., McHugh, T.H. 2024. Benefits of isochoric freezing for carrot juice preservation. Journal of Food Science. 89(3).

Interpretive Summary: Carrot juice is one of the most popular and preferred juices. Carrot juice is also a good source of carotenes. However, fresh carrot juice has a very short shelf life. The food industry commonly uses thermal treatments at high temperatures to extend the shelf life. However, the heat in such treatments can induce the loss of heat sensitive nutrients. This study shows the suitability of isochoric freezing for preserving the quality of carrot juice and maintaining its microbiological stability for 12 weeks. Isochoric frozen juice has a higher total carotenoid content, total soluble phenolic content and total antioxidant capacity than the fresh and heat-treated juices after 12 weeks. This is due to better extractability of nutrients under high pressure as well as processing at subfreezing temperatures that prevents the fast degradation of bioactive compounds. In addition, isochoric freezing enhances the orange color of the juice.

Technical Abstract: Isochoric freezing at -5 °C/77 MPa and -10 °C/100 MPa was used to preserve carrot juice for 12 weeks. The juice qualities were compared to those using heat treatment at 95 °C for 15s followed by cold storage at 4 °C. The native population of total aerobic bacteria, yeasts and molds in isochoric frozen juice remained below the detection limit for 12 weeks. In comparison, microbes started to grow in heat-treated juices after 3 weeks of refrigeration. The color of isochoric frozen juice appeared more deep orange than the fresh juice due to an increase in carotenoid extractability. Isochoric freezing was not effective in reducing the activities of peroxidase, polyphenol oxidase and pectin methyl esterase compared with heat treatment. However, the isochoric samples showed higher carotenoid content, polyphenol content and antioxidant capacity compared to the fresh and heat-treated juices. In addition, the isochoric samples retained a comparable viscosity to the fresh juice.