Enhancement of the antioxidant content of elderberry ( Sambucus nigra) fruit by pulsed ultraviolet light followed by spray drying of the elderberry juice.

摘要

Atoms or groups of atoms with unpaired numbers of electrons are called free radicals with the potential to damage cells by reacting with cell components and these damages may lead to diseases such as cancer and accelerate the aging process. Fruits and vegetables contain a variety of antioxidant compounds and these antioxidants are important free radical scavengers. Elderberries (Sambucus nigra) are gaining attention since many researchers have demonstrated their high polyphenols and anthocyanin content and their bioavailable antioxidant properties.;Spray drying of elderberry juice was investigated with varying air inlet temperature and feed flow rate. These operating parameters were optimized in terms of total phenolic content retention, color and recovery percentage of spray dried powder. The inlet temperature of 80°C with feed flow rate of 180 mL/hr gave better phenolic content retention but lower recovery of the powder i.e. less than 50%. To increase the recovery percentage, the elderberry juice was spray dried with five different wall materials, namely gum acacia, maltodextrin, soya protein powder, soya milk powder and isolated soya protein. Wall materials were evaluated in terms of total phenolic content retention, color of the powder and recovery percentage. The gum acacia and maltodextrin gave better results and higher recovery percentage with more than 70% powder recovery. In the storage stability evaluation, gum acacia turned out to be the best wall material with high phenolic content retention and low degradation in powder color.;Pulsed light treatments are mainly used for disinfection purposes. Considerable research has been done to enhance the nutritional value of fruits using continuous UV light; however the application of pulsed UV light technology in functional development in foods is in its budding stage. The changes in total phenolic compounds in elderberry (Sambucus nigra) treated with various pulsed ultraviolet rays (UV) were investigated. Four pulsed UV durations (i.e. 5, 10, 20, 30 seconds) at three energy dosages (i.e. 0.45, 0.6, 1.1 J/cm2/pulse) were considered for this research. The highest increment in total phenolics, around 50%, was found with 1.1J/cm2/pulse for a 10 seconds treatment. Even though most of the treatments indicated an increase in total polyphenols, some treatments resulted in a decrease in phenolics when compared to the control.