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Kirje Polyphenols and resveratrol from discarded leaf biomass of grapevine (Vitis sp.): Effect of cultivar and viticultural practices in Estonia : [data](Estonian University of Life Sciences, 2020) Rätsep, Reelika; Karp, Kadri; Maante-Kuljus, Mariana; Aluvee, Alar; Bhat, RajeevGrapevine leaves are a major by-product of viticulture practices derived from the leaf-removal from the fruit cluster zone in all vine growing regions. These leaves can be a valuable source of antioxidants to be used in pharmaceuticals or other health-related products. In this study, the leaves of grapevine cultivars were analysed by ultra-high performance liquid chromatograph-diode array detector () for the total polyphenols (TPC) and resveratrol a ected by cultivar, leaf-removal time and viticultural practice. The e ect of cultivar varied yearly, European grapevine cv. ‘Regent’ had increased TPC and resveratrol in comparison to ‘Boskoop’s Glory’, ‘Rondo’ and ‘Solaris’ in 2017, but ‘Solaris’ in 2018. TPC (1213–1841 mg 100 g-1) and resveratrol (1.061 mg 100 g-1) were higher in leaves of interspecific hybrid cvs. ‘Zilga’ and ‘Hasansky Sladky’ during full fruit ripeness. Cv. ‘Rondo’ grown under the polytunnel had decreased TPC in leaves. In conclusion, cultivar selection, viticultural practice and leaf-removal time contribute significantly to the accumulation of total polyphenols and resveratrol. Results of this study will contribute to better utilization of biomass produced in the vineyards, help to decrease the negative environmental impacts, and provide an overview on various factors a ecting the biochemical constituents, especially in leaves.Kirje Valorisation of sea buckthorn pomace by optimization of ultrasonic-assisted extraction of soluble dietary fibre using response surface methodology : [data](EMU DSpace, 2021) Hussain, Shehzad; Sharma, Minaxi; Bhat, Rajeev; ERA-Chair for Food (By-) Product Valorisation Technologies (VALORTECH). Estonian University of Life ScienceFruits and vegetable wastes/by-products of the dependent processing industries are considered to be a potential source of bioactive compounds. This fruit and vegetable waste is regarded as an underutilised resource and can be efficiently valorised to obtain value-added products. Sea buckthorn pomace is a valuable industrial waste/by-product obtained after juice production that contains bioactive, health promoting dietary fibres. After processing of the sea buckthorn berries (to obtain juice, jam and jellies), huge amounts of processing pomace is produced. Although, this pomace finds usage as animal feed or is simply discarded, owed to the lack of appropriate handling or processing facilities. As a result, significant amounts of nutrients are untapped and lost annually. The development of extraction techniques have validated the valorisation of pomace from fruits like sea buckthorn. Hence, the present study was designed to evaluate the effects of green extraction technologies such as ultrasonic-assisted extraction on the yield of soluble dietary fibre from sea buckthorn pomace. Response surface methodology coupled with Box–Behnken design was applied for optimization of SDF yield. Sonication temperature, sonication time and extraction power significantly increased the yield of soluble dietary fiber.Kirje Extraction of carotenoids from pumpkin peel and pulp: Comparison between innovative green extraction technologies (ultrasonic and microwave-assisted extractions using corn oil) : [data](EMU DSpace, 2021) Sharma, Minaxi; Bhat, Rajeev; ERA-Chair for Food (By-) Products Valorisation Technologies (VALORTECH). Estonian University of Life SciencesNatural pigments improve aesthetic value as well as antioxidant potential of a food product. This study was designed to determine the effects of green extraction techniques on carotenoids, polyphenols and antioxidant activities of pulp and peel of two varieties of pumpkin (Cucurbita maxima). Innovative green extractions (IGE; Ultrasound and Microwave-Assisted Extractions) synergised with corn oil (used as green solvent) were compared with conventional extraction (CE; hexane/isopropyl alcohol; 60:40, v/v). Results showed total carotenoids to be almost double on employing IGE (PM2-UAE-peel = 38.03 ± 4.21; PM4-UAE-peel = 33.78 ± 1.76 µg/g) when compared to conventional extraction (PM2-CE-peel = 19.21 ± 4.39; PM4-CE-peel = 16.21 ± 2.52 µg/g). Polyphenolic contents ranged between 510.69 ± 5.50 and 588.68 ± 7.26 mg GAE/100 g of extract in IGE, compared with conventional extracts (269.50 ± 2.17 to 318.46 ± 6.60 mg GAE/100 g) and percent inhibition of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) ranging between 88.32 ± 1.51 and 93.53 ± 0.30% in IGE when compared with conventional extraction (50.61 ± 1.44 to 57.79 ± 2.09%). Further, oxidative stability of carotenoids extracts from IGE (protection factor = 1.59 ± 0.01 to 1.81 ± 0.05) were found to be significantly higher (p < 0.05) than conventional extracts. Based on results, this study supports the use of innovative green extraction techniques to obtain bioactive pigments like carotenoids. It is anticipated that results generated will find potential applications in food, pharmaceutical and cosmetic industries.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 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 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 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 Natural pigments (anthocyanins and chlorophyll) and antioxidants profiling of European red and green gooseberry (Ribes uva-crispa L.) extracted using green techniques (UAE-citric acid-mediated extraction) : [data](Estonian University of Life Sciences, 2023) Hussain, Shehzad; Sharma, Minaxi; Jarg, Tatsiana; Aav, Riina; Bhat, RajeevGreen techniques to extract natural pigments are gaining prominence among consumers and food industries. This trend is predominantly due to the harmful effects imparted by commonly used synthetic dyes and the unwarranted stress created on our ecosystem. The objectives of this study were to obtain natural pigments (anthocyanins and chlorophyll) from Estonian-gown European green and red gooseberries by ultrasonic-assisted citric acid-mediated extraction method and perform antioxidant profiling (quantification via HPLC analysis). Green gooseberry extracts showed lower content of targeted compounds, with low concentrations of rutin (0.7–1.2 mg/ L) and quercetin 3-glucoside (0.9–1.3 mg/L), while in the red gooseberry extracts, the amount was slightly higher (1.4–6.9 and 1.0–1.3 mg/L, respectively) with 0.6–6.8 mg/L cyanidin 3-glucoside and 0.32–0.35 mg/L peonidin 3 glucoside recorded. Further, the yield of anthocyanins ranged between 1.14–1.79 and 1.86–3.63 mg/100 g in green and red gooseberries, respectively. Total phenols ranged between 162–392 and 263–987 mg GAE/100 g in green and red gooseberry extracts, respectively. The DPPH free radicals scavenging activity showed 73–86% and 87–91% inhibition in both green and red gooseberry, respectively. Results showed significant improvements in pigment extraction with higher values obtained for targeted antioxidant compounds using conventional and UAE extraction (aqueous extract), thus confirming that green extractions are a reliable technique to obtain pigments of interest from natural sources. The results support consumers’ demand and open up the avenue to explore pigments as natural colourants in food and cosmetics applications.Kirje Evaluation of different blackcurrant seed ingredients in meatballs by using conventional quality assessment and untargeted metabolomics : [data](Estonian University of Life Sciences, 2023) Kerner, Kristi; Kazernavičiūtė, Rita; Jõudu, Ivi; Rocchetti, Gabriele; Lucini, Luigi; Tänavots, Alo; Hussain, Shehzad; Venskutonis, Petras RimantasBlackcurrants are sources of phenolic compounds, such as anthocyanins, possessing strong antioxidant, anti- microbial and antifungal activity. Therefore, the addition of different blackcurrant pomace ingredients may affect the overall meat quality. The actual chemical profile and bioactivities of blackcurrant pomace ingredients may strongly depend on its preparation; for instance, in our study the highest values of the in vitro antioxidant capacity were determined for blackcurrant seeds after supercritical CO2 extraction. Starting from these back- ground conditions, in this work, we evaluated the ability of three different concentrations (namely 1, 3, and 5% w/w) of blackcurrant (BC) seeds following EtOH/water extraction (BC-AE), before supercritical fluid CO2 extraction (BC-RS), and after supercritical fluid CO2 extraction (BC-ASC) to affect different quality parameters of pork meatballs. These latter were stored considering three different time-points, namely 1, 3 and 6 days at 4 ◦C packed under modified atmosphere (i.e., 70% N2 and 30% CO2). Untargeted metabolomics allowed to identify several lipid and protein-related oxidation products involved in redox reactions, such as 13-L-hydroperoxylino- leic acid, (12S,13S)-epoxylinolenic acid, 9,10-epoxyoctadecenoic acid, glutathione, glutathione disulfide, L- carnosine, L-ascorbic acid, and tocotrienols. Besides, multivariate statistics applied on the metabolomics dataset confirmed that the chemical profile of meatballs was an exclusive combination of both BC inclusion levels and type of BC-ingredients considered. Our findings showed that the higher the concentration of BC seed ingredients in meatballs, the lower the cooking loss and the higher the fibre content. Also, all the ingredients significantly affected the colour parameters.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 Untargeted metabolomics and conventional quality characterization of rowanberry pomace ingredients in meatballs : [data](Estonian University of Life Sciences, 2023) Sarv, Viive; Kerner, Kristi; Venskutonis, Petras Rimantas; Rocchetti, Gabriele; Becchi, Pier Paolo; Lucini, Luigi; Tänavots, Alo; Bhat, RajeevIn this study, a rowanberry pomace defatted with supercritical CO2 (2%-AC), its ethanolic extract (1%-E) and extraction residue (2%-R), were tested in meatball preparation. The meatballs with 1%-E demonstrated the highest in vitro radical scavenging capacity. In the case of 1%-E the pH of meatballs was significantly lower compared to the control sample (P = 0.0132) on the 5-day. The lowest cooking loss was achieved when the meatballs contained mainly fibre-rich 2%-R. The UHPLC method detected 184 metabolites, including strong antioxidants, such as chlorogenic acids, 3′,4′-methylenedioxy-5,7-dimethylepicatechin, hyperin, isoquercitrin. The 1%-E was particularly effective against the development of unpleasant off-flavours caused by carbonyl compounds. Consistently, the decrease in lipid oxidation, indicated by reduced 7-dodecenal and 2,4-heptadienal contents, has been observed following the addition of rowanberry extract to meatballs. Metabolomics coupled with conventional quality evaluations provided a deeper understanding of the potential utilization and valor- isation of different rowanberry pomace extracts as meat ingredients.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.