Andmekogud
Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/6921
Sirvi
Sirvi Andmekogud Autor "Kaldmäe, Hedi" järgi
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Kirje Optimization of ultrasound-assisted extraction of phloretin and other phenolic compounds from apple tree leaves (Malus domestica Borkh.) and comparison of different cultivars from Estonia : [data](EMU DSpace, 2021) Ben-Othman, Sana; Kaldmäe, Hedi; Rätsep, Reelika; Bleive, Uko; Aluvee, Alar; Rinken, Toonika; ERA Chair for Food (By-) Products Valorisation Technologies VALORTECH. Estonian University of Life Sciences; Polli Horticultural Research Centre. Estonian University of Life SciencesPolyphenolic compounds, plant secondary metabolites essential for plant survival, are known for their high antioxidant and anti-inflammatory activity. In addition, several polyphenols, such as phloretin, also have potential antiviral effects, making these compounds potential ingredients of biofunctional foods. A promising source for the extraction of phloretin is a by-product of apple production—apple tree leaves. Focusing on green technologies, the first aim of the present study was to optimize the direct ultrasound-assisted extraction conditions to gain the maximum yield of phloretin from air-dried apple leaves. For the optimization of process parameters, we applied the response surface method with Box–Behnken design. The optimal extraction conditions were extraction time 14.4 min, sonication amplitude 10% and 10 g of sample per 100 mL solvent (70% ethanol, w/w). Using these conditions, we assessed the content of individual and total polyphenolic compounds along with antioxidant activity in the leaves of different autumn and winter apple cultivars grown in Estonia. The analyses were carried out with chromatographic (HPLC-DAD-MS/MS) and spectrophotometric methods. The phloretin concentration ranged from 292 to 726 µg/g and antioxidant activity from 6.06 to 11.42 mg GA eq./g, these being the highest in the local winter cultivars ‘Paide taliõun’ and ‘Tellissaare’, respectively.Kirje Phytochemical characterization of oil and protein fractions isolated from Japanese quince (Chaenomeles japonica) wine by-product : [data](Estonian University of Life Sciences, 2023) Ben-Othman, Sana; Bleive, Uko; Kaldmäe, Hedi; Aluvee, Alar; Rätsep, Reelika; Karp, Kadri; Maciel, Larissa Silva; Herodes, Koit; Rinken, ToonikaThe wine industry generates large quantities of by-products each year. Therefore, this work aimed to isolate and evaluate the oil and protein fractions of Japanese quince (Chaenomeles japonica, JQ) press residue, offering a partial utilization of valuable bioactive compounds of wine industry by-products. To study the JQ oil extract yield, composition and oxidation stability, we modified the co-solvent composition during the supercritical CO2 (SC–CO2) extraction of oil by adding different ethanol content. The remaining defatted material was used for the isolation of proteins. The SC-CO2 extraction yielded oil rich in polyunsaturated fatty acids, tocopherols, and phytosterols. The use of ethanol as a co-solvent increased the oil yield but did not enhance its oxidative stability or content of antioxidants. We recovered protein isolate after removing tannins with 70% ethanol extraction in the next step. The JQ protein isolate contained all essential amino acids. In addition to its balanced amino acid composition, the protein isolate exhibited excellent emulsifying properties highlighting its potential as a food additive. In conclusion, JQ wine by-products can be utilized for the extraction of oil and protein fractions which can be used in food or cosmetic product formulation.Kirje Recovery of polyphenols from vineyard pruning wastes - shoots and cane of hybrid grapevine (Vitis sp.) cultivars : [data](Estonian University of Life Sciences, 2021) Rätsep, Reelika; Karp, Kadri; Maante-Kuljus, Mariana; Aluvee, Alar; Kaldmäe, Hedi; Baht, RajeevGrapevine shoots and canes represent a significant amount of biomass, considered as a waste in viticulture. In cooler climates, grapevines are pruned in the autumn (October) and spring (March) due to harsh winter conditions (e.g., snow, low temperatures), and large amounts of biomass are produced at these different pruning times. This work was undertaken in order to investigate the potential of vineyard pruning waste for recovery of polyphenolic compounds for biomass valorization. Qualitative and quantitative analyses of grapevine shoot and cane polyphenols, including flavonoids and stilbenoids were performed using UHPLC MS/MS method. The results revealed the flavonols (quercetin) to be the most abundant compounds in shoots among all the three cultivars screened (Zilga, Hasansky Sladky, Rondo). Stilbenoids (ε-viniferin) dominated in the canes, while increased level of flavonols with lower contents of stilbenoids was detected in the endodormant canes, and higher amounts of flavanols and stilbenoids were recorded in eco-dormant canes. In conclusion, the content of polyphenols in grapevine shoots and canes differed among the cultivars and dormancy phases. The results generated from the present study contribute to the sustainable and environmentally friendly viticulture practice via valorization of vineyard pruning wastes.Kirje The use of oil-seed proteins as wall material for the production of plant-based spray-dried powders : [data](Estonian University of Life Sciences, 2024) Ben-Othman, Sana; Bleive, Uko; Kaldmäe, Hedi; Aluvee, Alar; Rätsep, Reelika; Sats, Andres; Pap, Nora; Järvenpää, Eila; Rinken, ToonikaData of the following article: The use of oil-seed proteins as wall material for the production of plant-based spray-dried powders.