Effect Of Ultrasound On Oualitv Of Fresh-squeezed Orange Juice

Orange juice is one of the most popular fruit juice, but commercially available orange juice is thermal sterilization, sensory quality, nutrient composition and aromatic substances of orange juice causing serious damage. Ultrasonic technique as a non-thermal processing methods, can keep the orange juice to a larger extent, natural flavor. At present, rarely reports about the effect of ultrasonic treatment on fresh-squeezed orange juice aromatic substances, so the research in this aspect is examined. In this paper, fresh-squeezed orange juice as experimental objects, from the study of fresh-squeezed orange juice volatile aromatic substances by the change of inquiry after ultrasonic treatment, ultrasonic effect on the sensory quality, fresh-squeezed orange juice basic physicochemical properties and some active components, and use the simulation effect of ultrasonic system for orange juice flavor characteristics effect. The main results are as follows:1、Fresh-squeezed orange juice volatile aromatic substances detected is38. Among them,18species of olefin,4kinds of esters,7alcohols,4aldehydes,2ketones and3other substances. From different conditions of ultrasonic experimental results, most types of volatile aromatic substances were45,47and45species at temperatures of5℃、10℃, and25%5min strength of ultrasound strength. After ultrasound, olefin by up to3(25%amplitude level), and reduce the maximum is7(45%amplitude level and25min); esters, alcohols and aldehydes increased respectively2,1and3, respectively is1, reduced3and3;except ketone there have no change in other materials by ultrasonic.2、Limonene was the highest, followed by valencene Limonene after ultrasonic treatment were substantially decreased, while the valencene was increased. The core content of orange juice aroma myrcene, a-pinene and decanal were reduced, while linalool is increased after the treatment. The main off-flavors such as a-terpineol, carvone and also changes with different ultrasonic treatment.3、The pH, total soluble solids (TSS) and titratable acid (TA) were3.66,10.80°Brix and0.68%(citric acid), respectively. Ultrasound can’t influence the pH, TSS and TA of fresh-squeezed orange juice, but will increase the cloud value and browning index. When the same cloud value, ultrasound reaches a certain degree, and the effect of intensity on the browning index of the most obvious. In addition, study on orange juice color, effect of temperature and time on the more obvious.4、Ultrasound can cause the content of ascorbic acid in fresh-squeezed orange juice decreased. The effect of temperature is the most obvious, at20℃ascorbic acid contents decrease to a maximum of53%, and with the prolongation of time but a slight increase. After ultrasonic treatment, total phenolics content in fresh-squeezed orange juice reduced, while the content of total flavonoids increased significantly, increased up to200%in the35%strength. 5、After ultrasonic processing model solutions of orange juice, the content of limonene and linalool was decreased, while increasing the content of carvone. The largest decline in limonene ultrasound at0℃is up to47%, strength of5%linalool decreased by a maximum of47%. Among them, influence of temperature on limonene, linalool is influenced by the strength of great impact.