Andmekogud
Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/6921
Sirvi
Sirvi Andmekogud Autor "Ben-Othman, Sana" järgi
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Kirje Immobilization of pectinolytic enzymes on nylon 6/6 carriers : [data](EMU DSpace, 2021) Ben-Othman, Sana; Rinken, Toonika; ERA Chair for Food (By-) Products Valorisation Technologies Valortech. Estonian University of Life SciencesPectinolytic enzymes are an important tool for sustainable food production, with a wide range of applications in food processing technologies as well as the extraction of bioactive compounds from pectin-rich raw materials. In the present study, we immobilized commercial pectinase preparation onto pellet and thread shaped nylon 6/6 carriers and assessed its stability and reusability. Five commercial pectinase preparations were tested for different pectin de-polymerizing activities (pectinase, polygalacturonase, and pectin lyase activities). Thereafter, Pectinex® Ultra Tropical preparation, exhibiting the highest catalytic activities among the studied preparations (p < 0.0001), was immobilized on nylon 6/6 using dimethyl sulfate and glutaraldehyde. The immobilization yield was in accordance with the carrier surface area available for enzyme attachment, and it was 1.25 ± 0.10 U/g on threads, which was over 40 times higher than that on pellets. However, the inactivation of immobilized enzymes was not dependent on the shape of the carrier, indicating that the attachment of the enzymes on the surface of nylon 6/6 carriers was similar. The half-life of enzyme inactivation fast phase at 4 °C was 12.8 days. After 5 weeks, the unused threads retained 63% of their initial activity. Reusability study showed that after 20 successive cycles the remaining activity of the immobilized pectinase was 22%, indicating the good prospects of reusability of the immobilized enzyme preparations for industrial application.Kirje Impact of pre-treatments and ultrasound technology on polyphenolic compounds extracted from potato peels : [data](EMU DSpace, 2021) Aav, Alice; Ben-Othman, Sana; Rätsep, Reelika; Jõudu, Ivi; Bhat, Rajeev; ERA Chair for Food (By-) Products Valorization Technologies of the Estonian University of Life Sciences (VALORTECH); Chair of Food Science and Technology. Estonian University of Life Sciences; Polli Horticultural Research Centre. Institute of Agricultural and Environmental Sciences. Estonian University of Life SciencesPotato (Solanum tuberosum L: Solanaceae family) is an important food crop throughout the world and is widely used as a raw material to produce starch, potato chips, fries, flour, etc. Being the fourth largest crop after rice, wheat, and maize, potato represents an essential part in human diet (Leo et al., 2008; Wu, 2016). Majority of the potato is processed into a pre-fabricated foods nowadays, and for most of the products, peeled potatoes are utilized, which leaves behind a great amount of potato peels as a waste. The peels are often utilized as a cattle feed or located to landfills, whereby causing additional cost to the processor (Kumari et al., 2017). The management of potato by-products (peels, juice etc.) has been a challenge as well as environmental problem for the potato processing industry for a long time due to their high pollution potency (Debestani et al., 2017; Venturi et al., 2019), therefore effective measures, for example valorization into a value-added products, such as functional and bioactive compounds, has to be taken. Furthermore, many studies report the need to reduce food loss and waste through using the underused food parts (for example potato peels) as a possible resource instead of a waste (Foley et al., 2011; Kumari et al., 2017).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 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.