Ultrasound irradiation of grapes: effect on the anthocyanin profile of “Isabella” juice

Abstract

PurposeThe aim of this study was to evaluate the effect of ultrasound (US) treatment on the postharvest of “Isabella” grapes and the consistency of the obtained results regarding the composition of anthocyanins in grape juice over three successive harvest years using a combination of analytical techniques.Design/methodology/approachJuices produced from “Isabella” grapes sonicated for different durations (3, 5, 7 and 10 min) were analysed. The grapes were harvested and sonicated in 2013, 2014 and 2015, and each treated sample was stored for 1, 3 and 5 days in order to verify the time necessary for the development of the US response. The juices were analysed through physicochemical analysis (total monomeric anthocyanins). The anthocyanin profiles were quantified and identified using high performance liquid chromatography coupled to photodiode array and mass spectrometry detectors (HPLC-PDA-MSn).FindingsThe results demonstrated the potential of US in improving the quality of grape juice. In all three harvests, it was observed that the treatments were effective in increasing the concentration of anthocyanins. For the 2013 harvest, the application of US for 5 min led to a 103% increase in juice pigments. However, the US response profile varied among the three harvests, indicating that the US effect was influenced by the ripening conditions of the fruit. In total, 33 anthocyanins were identified in the grape juice. For the first time, peonidin-3-p-coumaroyl glucoside-5-glucoside was identified in “Isabella” juice.Originality/valueThe results of this study validated US treatment as a simple and effective physical method that can be used as an alternative technology for improving the general quality of products such as juice by increasing the pigment concentrations that are linked to the colour and antioxidant potential of drinks. Moreover, the results demonstrate that US treatment may be less effective in the case of a sample with distinct phenolic maturation.

Enhancing peach slices radio frequency vacuum drying by combining ultrasound and ultra-high pressure as pretreatments: Effect on drying characteristics, physicochemical quality, texture and sensory evaluation

“…Zhang et al [31] reported that US could substantially improve the contents of free, esterified and insoluble-bound phenolics in mangoes. Similar results were obtained by Comarella et al [32] on “Isabella” grape and Li et al [33] on blueberry.…”

Impact of ultrasonication applications on color profile of foods

“…Therefore the color values of raw milk and treated milk were not statistically different [143] . In a more recent study, Comarella et al [35] noticed an increased concentration of monomeric anthocyanins in “Isabella” grape juice due to US irradiation because of the synergism between sonication time and temperature leading to increased release of bioactive compounds. They divulged that the free radical formation and mechanical perturbation could trigger the defense responses in plants activating secondary metabolism and stimulating the production of phenolic substances like anthocyanins and flavonoids, which could, in turn, improve the color properties of such products.…”

“…Ultrasonic irradiation treatment/pre-treatment application also ensures increased effectiveness of the succeeding process or unit operation to be applied, for instance, drying or cooking. In addition, it is widely used to increase the extraction of bioactive compounds from fruit/vegetables and all kinds of food by-products [128] , oil recovery from oil seeds plant [85] , bioethanol yield from lignocellulosic materials [90] , or alcoholic/nonalcoholic beverages processing [114] , [35] . Besides these, using ultrasonic irradiation alone can also significantly affect foods' physical and chemical properties [197] .…”

Efecto del pretratamiento con ultrasonido sobre la calidad del aceite crudo de palma (Elaeis guineensis)

“…Los antioxidantes, compuestos fenólicos y polifenólicos totales del ACP tienen la capacidad de combatir el estrés oxidativo e inhibición de los radicales libres que causa enfermedades y envejecimiento prematuro a los seres humanos (Chinenye et al, 2020;Baena et al, 2021). Comarella et al (2021), reportó una mayor concentración de antocianinas monoméricas en el jugo de uva "Isabella" debido a la irradiación con US que causa sinergia entre el tiempo de sonicación y la temperatura que conduce a una mayor liberación de compuestos bioactivos, generando la formación de radicales libres y la perturbación mecánica que desencadenan las respuestas de defensa en las plantas activando el metabolismo secundario y estimulando la producción de sustancias fenólicas como antocianinas y flavonoides, que mejoraran las propiedades de color de dichos productos.…”