Effect of gamma irradiation on microbiological, chemical, and sensory properties of fresh ashitaba and kale juices

• Published in: Radiation physics and chemistry (Oxford, England : 1993) England : 1993), 2012-08, Vol.81 (8), p.1076-1078
• Main Authors: Jo, Cheorun, Ahn, Dong Uk, Lee, Kyung Haeng
• Format: Article
• Language: English
• Subjects: Brassica; Chemical properties; Decimals; Demand; Fruits; Gamma irradiation; Irradiation; Juices; Microbiological properties; Microorganisms; Reduction; Sensory properties; Vegetable juice; Vegetables
• ISSN: 0969-806X; 1879-0895
• DOI: 10.1016/j.radphyschem.2011.11.065

Due to the popularity of health effects upon intake of fresh fruits and vegetables, the demand for fresh vegetables and fruit juices has rapidly increased. However, currently, washing is the only procedure for reducing contaminated microorganisms, which obviously limits the shelf-life of fresh vegetable juice (less than 3 days). In this study, we examined the effects of irradiation on the microbiological, chemical and sensory properties of ashitaba and kale juices for industrial application and possible shelf-life extension. Freshly made ashitaba and kale juices already had 2.3×105 and 9.5×104CFU/mL, respectively. Irradiation of 5kGy induced higher than 2 decimal reductions in the microbial level, which was consistently maintained during storage for 7 days under refrigerated conditions. Total content of ascorbic acid in vegetable juice decreased upon irradiation in a dose-dependent manner. However, the content of flavonoids did not change, whereas that of polyphenols increased upon irradiation. In sensory evaluation, the ashitaba and kale juices without irradiation (control) scored lower than the irradiated samples after 1 and 3 days, respectively. This study confirms that irradiation is an effective method for sterilizing fresh vegetable juice without compromising sensory property, which cannot be subjected to heat pasteurization due to changes in the bioactivities of the products. ► We examined the effects of irradiation of fresh vegetable juices (ashitaba and kale) for industrial application. ► Irradiation of 5kGy induced higher than 2 decimal reductions in the microbial level. ► Ascorbic acid in vegetable juice decreased upon irradiation in a dose-dependent manner. ► Content of flavonoids did not change whereas that of polyphenols increased. ► There was no change in sensory properties after irradiation.