Seed oils of ten traditional Portuguese grape varieties with interesting chemical and antioxidant properties

Abstract

The main objective of the present work was to optimize the extraction conditions for simultaneous maximization of total reducing (TRC) and antioxidant (AC) capacities for lettuce (Lactuca sativa L.) by-products extracts, using response surface methodology. For this, a design of experiments (DOE) with different combinations of solvents (water, methanol and acetone) extraction temperatures (30-60 ºC) and time (10-60 min) on the TRC and AC was applied. Higher and consistent fittings using second order polynomial models of the experimental data with regard to TRC (R 2 =0.529, p lack of fit >0.05) and AC (R 2 =0.900, p lack of fit >0.05) were obtained with methanol. The optimum extraction conditions based on combination responses for TRC and AC were: 30 % methanol (v/v), 60 ºC and 60 min. A close agreement between experimental and predicted values was found when applying these conditions. Furthermore, when aqueous extracts were prepared (e.g. 45 °C, 10 min), these presented similar TRC and AC properties to those obtained by the above optimum extraction conditions, having the advantage of applying mild extraction conditions and avoiding the use of organic solvents in their preparation.

Chemical composition of cold pressed Brazilian grape seed oil

“…Our finds showed close values from Brazilian GSO to other grape seed oils (Fernandes et al, 2013;Madawala et al, 2012;Crews et al, 2006). In this context, γ-tocotrienol activity has received great attention due to its anti-inflammatory effects, acting on the NF-kB signaling pathway, confirming the functional effect of these compounds (Kaileh & Sen, 2010) and the inhibition of oxidative stress in HepG2 cells (Choi et al, 2010).…”

“…Tocols are the major primary antioxidant group present in vegetable oils (Fernandes et al, 2013). The γ-tocotrienol isomer was observed as a major GSO constituent.…”

“…the presence of minor constituents contributes to product quality and nutritional value improvements. There are numerous studies reporting minor compound concentrations in GSO produced in many countries, such as Portugal, Spain, Italy and France (Fernandes et al, 2013;Navas, 2009;Rubio et al, 2009;Crews et al, 2006). Similarly, it was important to characterize GSO from the Brazilian market as no data were found in the literature.…”

“…Bail et al (2008) investigated Austrian GSO antioxidant capacity (from 9.0 to 116.0 µM TE 100 g -1 of oil) and Fernandes et al (2013) worked with ten different oils from many varieties of Portuguese grapes, founding a range from 33.4 to 48.9 mmol TE 100 mL -1 of oil.…”

Determinação Da Difusividade Efetiva E Da Energia De Ativação De Sementes De Uva Bordô

“…Objetivando-se encontrar soluções viáveis para o aproveitamento desse resíduo, a produção do óleo de sementes de uva cultivadas no país apresenta-se como uma alternativa promissora, uma vez que as sementes apresentam teores de óleos que oscilam de 13 a 20 % dependendo da variedade, e este óleo é rico em ácidos graxos insaturados e antioxidantes (Fernandes et al, 2013).…”