ABSTRACT
Abstract Effect of sonication on the blueberry juice was studied by evaluating the pH, viscosity, electric conductivity, color, total sugars, soluble solids, polyphenol, anthocyanidin, and radical scavenging activities. There were not any remarkable (p > 0.05) change in pH and electric conductivity. However, viscosity and color of blueberry juice markedly (p < 0.05) enhanced with the extension of sonication time. Meanwhile, total sugars, soluble solids, polyphenol, and anthocyanidin were obviously enhanced (p < 0.05). Moreover, prominent increase (p < 0.05) was observed on DPPH, superoxide, and hydroxyl radicals scavenging activities of sonicated blueberry juice. The current results exhibited sonication effectively improved blueberry juice quality and enhanced its antioxidant activity.
ABSTRACT
ABSTRACT: To obtain blueberry juice with a high content of antioxidants it is necessary to introduce an enzymatic depectinization step into the process. Due to the importance of this step in the final properties of blueberry juice it is critical that the operation conditions be optimized. The aim of this research was to evaluate the effects of temperature, duration of treatment and enzymatic complex concentration on anthocyanin content and juice yield during enzymatic depectinization. Results indicated that the best factor combination was 50ºC during 1.3h and 4mg 100g-1 of LAFASE(r) CLARIFICATION and 8mg 100g-1 of LAFASE(r) HE GRAND CRU enzymatic complex concentration. Under these conditions, blueberry juice with 798.41±8.03mg of cyanidin-3-glucoside L-1 and a juice yield of 87% was obtained. The combination of the response surface and desirability function methodologies enabled the optimization of the blueberry juice during the depectinization step, in terms of anthocyanin content and juice yield.
RESUMO: Para obter o suco de mirtilo com um alto teor de antioxidantes, é necessário realizar uma etapa de despectinização enzimática durante o processo. Esta etapa influenciará nas propriedades finais do suco de mirtilo, então, é necessário que as condições de operação sejam otimizadas. O objetivo deste trabalho foi avaliar os efeitos da temperatura, duração do tratamento e concentração do complexo enzimático na concentração de antocianinas e no rendimento do suco durante a despectinização enzimática. Os resultados indicaram que a melhor combinação de parâmetros foi de 50ºC, durante 1 à 3h e uma concentração de complexo enzimático de 4mg 100g-1 de LAFASE(r) CLARIFICATION e 8mg 100g-1 de LAFASE(r) HE GRAND CRU. Sob estas condições, foi obtido o suco de mirtilo com 798.41±8.03mg de-cianidina-3-glicosídeo L-1 e um rendimento de suco de 87%. A combinação das metodologias de superfície de resposta em função da preferência possibilitaram a otimização da despectinização do suco de mirtilo, em termos de teor de antocianinas e rendimento de suco.
ABSTRACT
PURPOSE: Fruit and vegetable juices are known to be rich sources of antioxidants, which have beneficial effects on diseases caused by oxidative stress. The purpose of this study was to directly compare the antioxidant activities of fruit and vegetable juices marketed in Korea. METHODS: We analyzed four fruit juices, two vegetable juices, two yellow-green juices, and six mixed vegetable juices. Antioxidant activities were analyzed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonate) (ABTS) test, and oxygen radical absorbance capacity (ORAC) assay. Protective effects against DNA damage were determined using an ex vivo comet assay with human lymphocytes. RESULTS: DPPH radical scavenging activities were in the following order: blueberry juice > mixed vegetable C juice > kale juice > mixed vegetable P juice > grape juice. ABTS radical scavenging activities were in the following order: blueberry juice > mixed vegetable C juice > grape juice > mixed vegetable P juice > kale juice. Peroxyl radical scavenging activities as assessed by ORAC assay were in the following order: blueberry juice > kale juice > mixed vegetable C juice > grape juice. Grape or blueberry juice showed strong abilities to prevent DNA damage in lymphocytes, and the difference between them was not significant according to the GSTM1/GSTT1 genotype. CONCLUSION: Antioxidant activities of fruit and vegetable juices and ex vivo DNA protective activity increased in the order of blueberry juice, grape juice, and kale juice, although the rankings were slightly different. Therefore, these juices rich in polyphenols and flavonoids deserve more attention for their high antioxidant capacity.