In this paper, the antioxidant capacities and compositions of two commercialized tea products and extracts from Fuzhuan brick tea (FBT) were investigated using three HPLC methods comparing the retention times of injected standards. Principal component analysis and DPPH-spiking HPLC analysis were used to analyze correlation between antioxidant capacity and the compounds detected to screen which compounds contribute to antioxidant activity. Results indicated that all samples contained high amounts of polysaccharides, phenols, and flavonoids and had good antioxidant activity and a high level of correlation among them. Furthermore, gallic acid, epigallocatechin, epicatechin, and epigallocatechin gallate were screened and found to be stronger antioxidant candidates. In summary, the quality of the FBT extracts was not inferior to that of commercialized tea products, suggesting the feasibility that extracts may directly act as instant tea products.

We assessed the effects of ultrasonic frequency, power, temperature and exposure time on the electric conductivity (EC) of wine to evaluate the feasibility of the online EC monitoring as an indicator to reflect the changes of wine quality under the ultrasound irradiation. Results showed that the continuously monitored curve of EC was significantly different from the values recorded at the beginning and end of sonication. An abrupt rise and a rapid drop of wine EC were observed at the start and end points of sonication, respectively, in all working conditions. With regards to the assayed wine temperatures, the effect exerted by this parameter on EC before sonication was totally different from that observed when the samples were cooled down after ultrasound treatment. All in all, these results suggest that the online EC monitoring of wine may be used as an efficient indicator to control and reflect the real changes of wine under ultrasound treatment. Seguimiento online de la conductividad eléctrica del vino inducido por ultrasonido RESUMEN Hemos estudiado los efectos de la frecuencia de ultrasonido, la potencia, la temperatura y el tiempo de exposición en la conductividad eléctrica (EC) del vino para evaluar la viabilidad del seguimiento EC online como indicador para reflejar los cambios en la calidad del vino bajo irradiación de ultrasonido. Los resultados mostraron que la curva de EC supervisada en continuo fue significativamente diferente de los valores registrados al principio y al final de la sonicación. Se observaron un aumento brusco y una rápida caída de EC del vino al principio y al final de la sonicación, respectivamente, para todas las condiciones estudiadas. En referencia a las temperaturas testadas del vino, el efecto ejercido por este parámetro en EC antes de la sonicación fue totalmente distinto de aquel observado cuando se enfriaron las muestras después del tratamiento de ultrasonido. En resumen, estos resultados sugieren que el seguimiento online de EC del vino podría ser utilizado como un indicador eficiente para controlar y reflejar los cambios reales en el vino con el uso de tratamiento de ultrasonido.

In this paper, the physicochemical properties of the Semen Astragali Complanati wine was first investigated including the pH, electrical conductivity (EC), titratable acid, alcohol content, residual sugars, chromatic characteristics and flavonoids, and thereafter the in-vitro antioxidant capacity and its correlation with the total phenolic and flavonoids content were systematically evaluated and analyzed for the different fractions of the Semen Astragali Complanati wine by six antioxidant assays and the Pearson product-moment correlation, respectively. On a whole, there are no significant differences between the Semen Astragali Complanati wine and the grape wine regarding most of the conventional enological parameters. The antioxidant assays showed that the Semen Astragali Complanati wine exerts great antioxidant capacity, which is attributed to the high content of polyphenols and flavonoids contained such as complanatoside A and rhamnocitrin, since high correlations exhibited between the total content of phenols and flavonoids, and the in-vitro antioxidant activity, respectively. All these results indicate that the Semen Astragali Complanati could be fermented to wine and be as a natural source of antioxidants preventing damage associated with free radicals and offer alternatives to develop high value-added products to enhance health benefits.Las propiedades fisicoquímicas y la capacidad antioxidante in vitro del vino de Semen Astragali Complanati RESUMEN En este estudio se han investigado las propiedades fisicoquímicas del vino de Semen Astragali Complanati incluyendo el pH, la conductividad eléctrica, la acidez valorable, el contenido de alcohol, los residuos de azúcares, las características cromáticas y los flavonoides, después se evaluó sistemáticamente la capacidad antioxidante in vitro y su correlación con el contenido total de fenoles y flavonoides. Además se analizaron diferentes fracciones de vino de Semen Astragali Complanati mediante seis ensayos antioxidantes y la correlación producto-momento de Pearson, respectivamente. En conjunto, no se encontraron diferencias significativas entre el vino de Semen Astragali Complanati y el vino de uva en lo que concierne a los principales parámetros enológicos. Los ensayos antioxidantes mostraron que el vino de Semen Astragali Complanati ejerce una gran capacidad antioxidante, la cual se atribuye al alto contenido de polifenoles y flavonoides que contienen complanatoside A y ramnocitrina, debido a las altas correlaciones exhibidas entre el contenido total de fenoles y flavonoides, además de la actividad antioxidante in vitro, respectivamente. Todos estos resultados indican que Semen Astragali complanati podría ser fermentado a vino y ser una fuente natural de antioxidantes que previene los daños asociados con los radicales libres, además de ofrecer alternativas al desarrollo de productos con un alto valor añadido para favorecer beneficios para la salud. ARTICLE HISTORY

Change in electrical conductivity is considered a potential indicator for the on-line monitoring of wine aging accelerated by ultrasound, as determined in our previous study; however, the exact mechanism of change is currently unclear. In this study, the ion content and the total ionic strength were analyzed by ion-exchange chromatography to investigate the change mechanism of the electrical conductivity of wine under ultrasound irradiation. The results indicate that the changes in wine electrical conductivity during ultrasound treatment correlate with the changes in the cations (Na+, K+, Ca2+, Mg2+, and NH4+) and in the anions from the organic acids (malic acid, citric acid, tartaric acid, oxalic acid, and formic acid) and inorganic acids (Cl-, SO42-, and PO43-), especially for the ionic strength of the wine. Overall, electrical conductivity may be used to reflect the chemical reactions related to wine aging to a certain extent because the reactions can be initiated by the conversion of cations and by the degradation or auxiliary function of organic acids.