Physico-chemical parameters, bioactive compounds and microbial quality of thermo-sonicated carrot juice during storage

• Published in: Food chemistry 2015-04, Vol.172, p.650-656
• Main Authors: Martínez-Flores, Héctor E., Garnica-Romo, Ma. Guadalupe, Bermúdez-Aguirre, Daniela, Pokhrel, Prashant Raj, Barbosa-Cánovas, Gustavo V.
• Format: Article
• Language: English
• Subjects: Ascorbic Acid - analysis; Beverages - analysis; Beverages - microbiology; Bioactive compounds; Carotenoids - analysis; Carrot juice; Chemical Phenomena; Cold Temperature; Colony Count, Microbial; Daucus; Daucus carota - chemistry; Daucus carota - microbiology; Food Contamination - analysis; Food Contamination - prevention & control; Food Microbiology; Food Quality; Food Storage - methods; Hydrogen-Ion Concentration; Microbial growth; Shelf-life; Sonication - methods; Storage; Thermo-sonication
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2014.09.072

•Ultrasound combined with mild temperatures was applied in fresh carrot juice.•Microbial growth and physicochemical quality were assessed in the treated juice.•Juice sonicated at 58°C had low microbial growth after 20d of storage at 4°C.•Juice sonicated at 58°C retained >98% of carotenoids and 100% of ascorbic acid. Thermosonication has been successfully tested in food for microbial inactivation; however, changes in bioactive compounds and shelf-life of treated products have not been thoroughly investigated. Carrot juice was thermo-sonicated (24kHz, 120μm amplitude) at 50°C, 54°C and 58°C for 10min (acoustic power 2204.40, 2155.72, 2181.68mW/mL, respectively). Quality parameters and microbial growth were evaluated after processing and during storage at 4°C. Control and sonicated treatments at 50°C and 54°C had 10, 12 and 14d of shelf-life, respectively. Samples sonicated at 58°C had the best quality; microbial growth remained low at around 3-log for mesophiles, 4.5-log for yeasts and molds and 2-log for enterobacteria after 20d of storage. Furthermore, thermo-sonicated juice at 58°C retained >98% of carotenoids and 100% of ascorbic acid. Phenolic compounds increased in all stored, treated juices. Thermo-sonication is therefore a promising technology for preserving the quality of carrot juice by minimising the physicochemical changes during storage, retarding microbial growth and retaining the bioactive compounds.