Superior Valorisation of Juglans regia L. Leaves of Different Maturity through the Isolation of Bioactive Compounds

Extracts rich in bioactive compounds from natural sources have received great interest due to their great impact on human health. The aim of this research is focused on the obtaining and characterization of several extracts from Juglans regia L. leaves in four different maturity phases: young green leaves (YGL), green leaves (GL), mature green leaves (MGL), and yellow leaves (YL), using different solvents: ethanol (e), water (w), or water:ethanol (1:1 (v/v)-m) by employing several methods: magnetic stirring (MS), ultrasound-assisted (UA), as well as maceration (M). The obtained extracts were quantitatively evaluated through spectrophotometric methods: Total Polyphenol Content (TPC-Folin-Ciocalteu assay) and Total Antioxidant Capacity (TEAC assay). Phytochemical screening by means of Fourier-Transform Ion-Cyclotron-Resonance High-Resolution Mass Spectrometry (FT-ICR-MS) indicated the presence of 40 compounds belonging to different phytochemical classes: phenolic acids, flavonoids, flavones, flavanones, flavonones, flavanols, vitamins, tereponoid, steroid, anthocyanidin, and other compounds. Based on TPC and TEAC assays, the water-ethanol mixture was found to be the proper extraction solvent, with the best results being obtained for YL plant material: 146.29 mg GAE/g DM (TPC) and 11.67 mM TE/g DM (TEAC). This type of extract may be used in various domains, such as the cosmetics industry, the biomedical field, and/or the design of functional foods, relying on their phytochemical composition.

Enzymatic pre-treatment of grape seeds for an oil with higher antioxidant activity

The paper investigates the effect of the enzymatic pre-treatment of grape seeds from six Romanian cultivars on the oil extracted. The grape seeds of some white and red Romanian grape varieties were separated from winery waste, washed, dried and ground, with the oil then obtained by extraction with petroleum ether. The extraction was performed directly or after a preliminary treatment with a commercial pectin lyase. The enzymatic procedure applied was more cost effective compared to other treatments previously described in which a cocktail of enzymes was used. The quantity of the extracted oil was measured in both types of processing, with an increase being observed for pre-treated samples. The fatty acid profiles (FAPs) of the oils resulted for the treated and untreated seeds were determined. No change in the composition was noticed. The reductive power of these oils was also investigated. Compared to the untreated samples for the same variety, the enzyme pre-treatment resulted in a superior antioxidant capacity.

Influence of composition on the thermal behavior of oils extracted from the seeds of some Romanian grapes

BACKGROUND

The oils obtained from grape seeds are becoming a valuable way of exploiting winery waste and their properties are scrutinized for evaluating the potential usages. We examined the oils extracted with petroleum ether from grape seeds of four varieties of grapes (Cabernet Sauvignon, Feteasca Neagra, Merlot and Pinot Noir) from Romania looking at the influence of the fatty acid profile and of the antioxidants on their thermal behavior.

RESULTS

The fatty acid profiles of the oils were evaluated by ¹ H-NMR spectroscopy, and the oil antioxidant capacity was determined by cupric ion reducing antioxidant capacity (CUPRAC) method. The main fatty acid component in all the oils is linoleic acid (over 70%), which, due to its known health benefits, make the oils of commercial interest. The thermal stability of grape seed oils appears to be mainly influenced by the percentage of polyunsaturated fatty acids in their composition, less polyunsaturated fatty acids making the oils more stable. The antioxidant compounds affect only the initial stage of the decomposition by limiting the formation of hydroperoxides in the allylic positions of the fatty acid chain.

CONCLUSION

Compared to pure samples of glyceryl-unsaturated fatty acids (glyceryl-trioleate, glyceryl-trilinoleate), the grape seed oils exhibit higher thermal stability, due to the presence of antioxidant compounds and to a synergistic action of unsaturated and saturated fatty acids, smaller percentage of the polyunsaturated and higher percentage of the saturated fatty acids enhancing the stability. © 2019 Society of Chemical Industry.

Fatty Acid Profile of New Varieties of Grape Seed Oils Based on NMR Data and Their Authentication

Grape seeds from five known red grape sorts and two new local sorts, obtained by hybridization of red and white varieties, have been valorized as vegetal oils, through good yield extraction. The fatty acid content the of obtained oils was determined by GC-FID, as methyl esters, and directly by 1H-NMR spectroscopy. The obtained grape seed oils have a high content in linoleic acid (over 70%) and a relatively low quantity of saturated fatty acid (stearic and palmitic). Both measurement methods gave similar results confirming the accuracy of the spectroscopic method, which is less time and reagent consuming. Based on the fatty acid profile (FAP) of the oils, determined by either FT-IR or 1H-NMR and using the Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA) statistical methods, the discrimination between the classical known grape sorts and the new local varieties could be achieved. The results show that such method is appropriate for discovering possible adulteration of the grape oils, valuable products due to the essential unsaturated acid content.

Authentication and Nutritional Benefits of Cheeses Based on Vegetable Oils

The fatty acid profile of a number of commercial fermented cheeses, based on vegetable oils or milk lipids have been evaluated by GC-FID (gas chromatography with flame ionization detector), disclosing the quantity of SFAs (saturated fatty acids), MUFAs (monounsaturated fatty acids) and PUFAs (polyunsaturated fatty acids), as well as the presence of small quantities of TUFAs (trans unsaturated fatty acids) in the dairy products. The authentication of the cheeses based on vegetable oil or milk was performed by GC or IR fingerprinting.