Effect of high power ultrasound on the anthocyanins content and nonenzymatic browning in blueberry fruit nectre

Abstract

Svrha ovog rada je utvrditi djelovanje ultrazvuka visoke snage (amplitude, vremena i temperature) na udio antocijana, ukupnih fenolnih spojeva, te na neenzimatsko posmeđivanje i promjene boje nektra od borovnice. Primijenjen je tretman ultrazvučnom sondom promjera 12,7 mm. Eksperiment je dizajniran pomoću računalnog programa STATGRAPHICS Centurion, faktorijalnim planom eksperimenta, te su korištene tri amplitude (60, 90 i 120 μm tj. 50, 75 i 100 % snage) i različita vremena tretiranja (3, 6 i 9 min). Rezultati su statistički obrađeni metodom odzivne površine. Rezultati HPLC analize pokazuju da su najzastupljeniji antocijani cijanidin-3-glukozid, cijanidin-3- glukozilrutinozid, cijanidin-3-rutinozid i cijanidin-3-soforozid od kojih se kvantitativno najviše ističe cijanidin-3- soforozid. Iz rezultata je vidljivo da je najsvjetliji uzorak BO2 tj. najsličniji netretiranom uzorku. Najveći stupanj neenzimatskog posmeđivanja ima uzorak BO5 koji je tretiran najvišom amplitudom i najduljim vremenom tretiranja. Kod ukupnih fenola najveću koncentraciju također ima uzorak BO5 a najmanju uzorak BO8 tretiran 3 minute pri amplitudi 50 %.The aim of this work was to determine the effect of high power ultrasound (amplitude, time and temperature) on the content of anthocyanins, total phenolic compounds, as well as nonenzymatic browning and color of the nectar of blueberries. Experiment has been designed in STATGRAPHICS Centurion software using factorial design. The treatment was performed using ultrasonic probe diameter of 12,7 mm, at three amplitudes (of 60, 90 and 120 μm, equivalent to 50, 75 and 100% of power) and different times of treatment (3, 6 and 9 min). The results were statistically analyzed by a computer program using response surface methodology. HPLC results showed that cyanidin-3-glucoside, cyanidin-3-glucosylrutinoside, cyanidin-3-rutinoside and cyanidin-3-sophoriside were the major anthocyanins of which are quantitatively the most notable cyanidin-3-soforozid. The results show that the brightest sample is BO2 and untreated sample was immediately followed by the brightness. The greatest degree of nonenzymatic browning has a sample BO5 which was treated with highest amplitude and the longest treatment. The highest concentration of total phenolic has sample BO5 treated 9 minutes at amplitude 100 % while the sample BO8 has minimum treated 3 minutes at amplitude 50 %