Selection of optimal thermal process parameters for the production of sea buckthorn beverages with high antioxidant activity and long shelf-life
2012
Kyriakopoulou, K. (National Technical University of Athens (Greece). School of Chemical Engineering, Design and Process Analysis Laboratory) | Katsaros, G. (National Technical University of Athens (Greece). School of Chemical Engineering, Laboratory of Food Chemistry and Technology) | Taoukis, P. (National Technical University of Athens (Greece). School of Chemical Engineering, Laboratory of Food Chemistry and Technology) | Krokida, M. (National Technical University of Athens (Greece). School of Chemical Engineering, Design and Process Analysis Laboratory)
Sea buckthorn (Hippophae rhamnoides L.) is a unique medicinal and aromatic plant and belongs to the family of Elaeagnaceae. Sea buckthorn juice, derived from the sea buckthorn berries, provides a nutritious beverage, high in suspended solids and rich in vitamin C and carotenes. In view of its highly perishable nature, sea buckthorn juice has to be processed in order to extend its shelf-life. The objective of this study was to evaluate the effect of mild heat treatment on microbial behavior and the shelf-life extension of sea buckthorn beverages during storage at temperatures from 5 to 20 °C. Two different beverages were produced by mixing sea buckthorn juice with concentrated fruit juices from orange or pomegranate. These beverages were evaluated through storage time. Thermal treatments were applied at 60, 70 and 80 °C for 1, 3 and 5 min. Total aerobic microflora and yeasts and moulds were enumerated through the whole storage period at appropriate time intervals. Total antioxidant activity was measured for produced samples. Sensory evaluation was performed before microbial analysis of all samples. All thermal treatments delayed the recovery and the growth of all studied microorganisms during storage. All the obtained results were kinetically described. The effect of temperature on the deterioration rates was studied. The shelf-life of all beverages was determined based either on the growth of microorganisms or on the reduction of antioxidant activity, depending on the storage temperature. The optimum process conditions were chosen based on the shelf-life extension which was estimated according to the higher antioxidant activity and the simultaneous lower microorganisms’ growth rates.
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