Efectos del secado al aire y solar sobre la calidad nutricional del aceite, las semillas y pieles de las uvas Muscat Hamburg

Abstract

Grape pomace is an agro-industrial by-product from the production of must (grape juice) by pressing whole grapes. In order to evaluate the seeds and skins of the grape pomace, it must first be dried and then separated in a screen machine. The drying of pomace is an important and necessary process for the optimum separation of seeds. The main purpose of this study was to determine the optimum drying process for obtaining high-quality grape seed oil. In this research, open air and solar energy drying methods were compared in terms of water activity, total bacterial and mold-yeast count, along with the chemical and fatty acid compositions of pressed grape residues. Oleic acid and linoleic acid contents ranged from 16.56-16.96% and 71.45-71.96%, respectively. Antioxidant activities ranged from 2.33-2.80 µmol trolox/g. The results showed that the drying methods did not decrease the nutritional quality of grape residues and prevented microbial growth by decreasing water activity to below 0.60. RESUMEN: Efectos del secado al aire y solar sobre la calidad nutricional del aceite, las semillas y pieles de las uvas MuscatHamburg. El orujo de uva es un subproducto agroindustrial de la producción de mosto (jugo de uva) al prensar las uvas enteras. Para poder evaluar las semillas y las pieles del orujo de uva, primero debe secarse y luego separarse mediante una máquina de tamizado. El secado del orujo es un proceso importante y necesario para una separación óptima de las semillas. El objetivo principal de este estudio fue determinar el proceso de secado óptimo para obtener aceites de semillas de uva de alta calidad. En este trabajo, los métodos de secado al aire libre y la energía solar de los residuos de uva prensados se compararon en términos de actividad de agua, recuento total de bacterias y moho, así como la composición de ácidos grasos. Los contenidos de ácido oleico y linoleico variaron entre 16,56-16,96% y 71,45-71,96%, respectivamente. Las actividades antioxidantes variaron entre 2,33-2,80 μmol trolox/g. Los resultados mostraron que los métodos de secado no disminuyeron la calidad nutricional de los residuos de la uva y evitaron el crecimiento microbiano al disminuir la actividad del agua por debajo de 0,60.

Potential of grape byproducts as functional ingredients in baked goods and pasta

“…The studies confirm that the fatty acids composition of grape byproducts differs depending on the processing method, the oil contents of grape juice byproducts being lower than of the wine byproducts (Gülcü et al, 2019). Taşeri et al (2018) showed that the drying method significantly affected (p < .05) the free fatty acid contents of seeds, which depend on the lipase activity, the open air method providing better results.…”

“…Gülcü et al (2019) reported that the principal sugars of grape juice and wine byproducts are fructose and glucose, whereas saccharose can be found only in seeds. According to the results reported by Taşeri et al (2018), the drying method significantly affects (p < .05) the sugar content of grape peels, the open air solution being better than a solar collector. Mendes et al (2013) analyzed white grape peels and showed that the main neutral sugars were rhamnose, fucose, arabinose, xylose, mannose, galactose, and glucose.…”

“…The moisture directly affects the chemical and microbiological stability of grape byproducts (Mironeasa, 2017;Sousa et al, 2014). The final moisture of grape byproducts that can be used as food ingredients depends on the processing methods and drying conditions (Mironeasa et al, 2017;Taşeri et al, 2018).…”

“…Vegetables and fruit byproducts are valuable ingredients that can be used to enrich foods, wine industry being one of the fields that produce this kind of waste. Grape pomace is the solid waste that remains after pressing; it represents about 20% of the grape and is composed of peels, seeds, and stalks (Bordiga, Travaglia, & Locatelli, 2019;Taşeri et al, 2018;Walker, Tseng, Cavender, Ross, & Zhao, 2014). About 30% to 40% of winery byproducts are valorized worldwide, being used for different purposes, mostly as animal feeds or fertilizers (Karnopp et al, 2015;Lavelli, Torri, Zeppa, Fiori, & Spigno, 2016;Maner, Sharma, & Banerjee, 2017).…”

“…The antioxidant constituents in grape seed are in highest concentration than in peels and steams and include several flavonoids with a phenolic nature such as monomeric flavanols, procyanidins, and phenolic acids (Jaisanthi & Banu, 2014;Tang et al, 2018). The most important polyphenols from grape seeds and peels are proanthocyanidins, flavonoids, phenolic acids, and stilbenes (Bordiga et al, 2019;Taşeri et al, 2018). Polyphenols digestion consists of absorption in the intestine along with the DFs and releasing from the matrix formed with fibers into the colon due to the favorable antioxidant environment created by the bacteria (Kawabata, Yoshioka, & Terao, 2019;Saura-Calixto, 2011).…”