Winemaking by-products as a source of phenolic compounds: Comparative study of dehydration processes

New anti-α-Glucosidase and Antioxidant Ingredients from Winery Byproducts: Contribution of Alkyl Gallates

“…These concentrations were above those recorded in the present study, possibly due to ethyl gallate being expressed as p -hydroxybenzoic acid equivalents and not being quantified with the appropriate standard. Beyond ethyl gallate, the methyl derivative has also previously been detected in grape byproducts (seed, stem, and pomace) . However, to date, only one study performed by Mir-Cerdá et al recovered ethyl gallate from winery lees at the average concentration of 2.10 μg/g dw, close to that found in this work (3.85 μg/g dw in freeze-dried samples) (Table ).…”

“…Beyond ethyl gallate, the methyl derivative has also previously been detected in grape byproducts (seed, stem, and pomace). 13 However, to date, only one study performed by Mir-Cerdáet al recovered ethyl gallate from winery lees at the average concentration of 2.10 μg/g dw, 28 close to that found in this work (3.85 μg/g dw in freeze-dried samples) (Table 1). Nonetheless, to date, no comprehensive information on all alkyl gallates monitored in the present work has been described in the literature (e.g., regarding butyl and lauryl gallates) that limits significantly the scope of the discussion on this issue.…”

“…These results evidenced that, although freeze-drying preserved gallic acid and galloyl esters derivatives to a higher extent than oven-drying, the materials dehydrated by the latter process also exhibited valuable concentrations (Table 1 alternatives including oven-drying conducted by applying an optimized drying time (hours)/temperature conditions for grape pomace (27 and 10 h at 40 °C) and grape stems (17 and 5 h at 60 °C), microwave, and spiral flash dryer. 13 Nevertheless, given that the application of freeze-drying at industrial levels is not a sustainable option in most cases, the reduction of the phytochemicals burden as a result of alternative dehydration processes should be assumed to a given extent marked by the maintenance of the functional traits. Moreover, freeze-drying is also enclosed to additional higher costs due to the packaging and storage requirements, due to increased porosity and hygroscopy, which could be associated with lower shelf life relative to conventional industrial processes such as that assayed in the present work.…”

Phenolic Composition of Red and White Wine Byproducts from Different Grapevine Cultivars from La Rioja (Spain) and How This Is Affected by the Winemaking Process

“…Nowadays, grape stems are a low-value product for animal feed or soil fertilizer. Different aspects of phenolic compounds in bunch stems, their extraction, factors that affect their concentrations, their bioactivity, and use, have been reviewed in detail very recently by Ferreyra et al However, some studies have recently highlighted the potential of this byproduct as a rich source of biocompounds with a wide spectrum of beneficial health properties. ,,,, Interestingly, the stems were proposed as wine preservative to replace/reduce the use of sulfur dioxide . Therefore, a comprehensive characterization of the phenolic profile of different cultivars will increase the commercial value of the stems, and this information could also be used for targeted applications for nutritional and health purposes.…”

“…Pretreatment. Before the chromatographic analysis, a solid−liquid extraction was performed following the methodology described by Costa et al 16 Briefly, 4 mL of extraction solution (methanol/Milli-Q water/formic acid, 79:20:1, v/v/v) was added to 200 mg of the lyophilized sample, vortexed, and stored overnight in the dark at 4 °C. Then, samples were sonicated (5 min, 40 Hz frequency) in an ultrasonic bath and centrifuged at 9000 rpm for 10 min at 20 °C to collect the supernatants.…”