Pressurized low polarity water extraction of lignans from whole flaxseed

The application of pressurized low polarity water (PLPW) extraction to the production of flaxseed lignans-rich products has been studied, and the key geometric and process conditions, including temperature, flow rate, and total volume have been determined and optimized. Maximum amounts of lignans and other flaxseed bioactive, including proteins were extracted at 160 °C and 5.2 MPa. However, on a dry weight basis the most concentrated extracts in terms of lignans and other phenolic compounds were obtained at 140 °C and 5.2 MPa. A flow rate of 0.5 mL/min was optimal for the extraction of lignans from flaxseed (Linum usitatissimum L.) and a total volume of 30–40 mL/g of seed was required to maximize the recovery. Higher flow rates increased the rate of the extraction but required larger water volumes. Bed depth to ID ratios of 5–18 resulted in faster extraction and maximum recovery (90–95%) at water to seed ratios of 30–50 mL/g. Larger depth to ID ratios (15–18) would allow the use of lower solvent to solid ratios (14–20 mL/g) and would still result in yields of 84–90%.     

Influence of extraction process on antioxidant capacity of spent coffee

Spent coffee that is produced in tons by restaurants and cafeterias, and consumers at domestic levels, could be a good opportunity to have an important source of natural antioxidants. The main aim of this work was to study the influence of several process factors on the antioxidant capacity extraction from spent coffee. Total phenolic compounds, radical scavenging activity (ABTS and DPPH) and browned compounds (Abs 420 nm) of spent coffee extracts obtained with continuous (Soxhlet 1 h and 3 h) and discontinuous methods (solid–liquid extraction and filter coffeemaker), several solvents (water, ethanol, methanol and their mixtures), successive extractions, and water with different pHs (4.5, 7.0 and 9.5) were carried out. Spent coffee extracts with the highest antioxidant capacity were obtained after one extraction with neutral water (pH 7.0) in a filter coffeemaker (24 g spent coffee per 400 mL water). Furthermore, spent coffee defatting and extract lyophilization allowed us to obtain spent coffee extracts powder with high antioxidant capacity that can be used as an ingredient or additive in food industry with potential preservation and functional properties.     

Optimization of supercritical fluid extraction of bioactive compounds from grape (Vitis labrusca B.) peel by using response surface methodology

Supercritical fluid extraction (SFE) was applied for the extraction of valuable compounds from grape (Vitis labrusca B.) peel. Extraction was carried out according to an orthogonal array design (OAD) and independent variables selected were temperature, pressure and modifier concentration. SFE process was optimized by using response surface methodology (RSM) for the extract yield, total phenols, antioxidants and total anthocyanins from grape peel. Effects of extraction temperature and pressure were found to be significant on all responses. Optimal SFE conditions were identified as 45–46 °C temperature, 160–165 kg cm^? 2 pressure and 6–7% ethanol as modifier for maximum extract yield (12.31%), total phenols (2.156 mg GAE/100 mL), antioxidants (1.628 mg/mL) and total anthocyanins (1.176 mg/mL). Experimental values for response variables at these optimal conditions match well with the predicted values. Grape peel extracts obtained by SFE showed more than 93% DPPH radical scavenging activities.Industrial relevanceThis study describes the response surface optimization of supercritical fluid extraction (SFE) process for the enhanced recovery of total phenols, antioxidant and anthocyanins from grape peel. SFE uses CO₂ as supercritical fluid which is environment friendly solvent; allows extraction at lower temperature and the extracts obtained possess higher quality and safety. Industrially, it may be used as a promising technique for the extraction of bioactive compounds from plant materials.     

Green tea preparation and its influence on the content of bioactive compounds

The effect of different extraction conditions and storage time of prepared infusions on the content of bioactive compounds of green teas and their antioxidant capacity were investigated. The content of total phenols, total flavonoids and total non-flavonoids in green teas was determined spectrophotometrically, while 7 flavan-3-ols, 6 phenolic acids and 3 methylxanthines were identified and quantified by using high performance liquid chromatography (HPLC–PDA). Among the tested green teas bagged green tea Twinings of London was recognized as the richest source of phenolic compounds (3585 mg/L GAE of total phenols). The most abundant phenolic constituents of green tea were flavan-3-ols, of which EGCG was prevailing in all teas (94.54–357.07 mg/L). The highest content of caffeine, as the most abundant methylxanthine, was determined in powdered green tea. The findings of this investigation suggest that extraction efficiency of studied bioactive compounds from green tea depends on the extraction conditions and that maximum extraction efficiency is achieved during aqueous extraction at 80 °C, for 5′ (powder), 15′ (bagged) and 30′ (loose leaf). In order to determine the antioxidant capacity of teas the DPPH, ABTS and FRAP assays were applied. Regardless of the extraction conditions all green teas exhibited significant antioxidant capacity in vitro, which was in correlation with their phenolic content, confirming that green tea is one of the best dietary sources of antioxidants.     

Citharexylum solanaceum fruit extracts: Profiles of phenolic compounds and carotenoids and their relation with ROS and RNS scavenging capacities

Citharexylum solanaceum is a native fruit from Brazil, which both bioactive compounds and antioxidant potential were not yet investigated. Thus, the freeze-dried extracts of seed and pulp + skin of C. solanaceum fruits were obtained after solid-liquid extraction with ethanol and their bioactive compounds composition, namely phenolic compounds and carotenoids, were determined. The antioxidant capacity of both extracts against physiologically relevant reactive oxygen species (ROS) and reactive nitrogen species (RNS) was further investigated. Both C. solanaceum extracts showed high contents of phenolic compounds; however, pulp + skin extract presented 2.4-times more phenolic compounds (33.54 mg/g) than the seed extract (14.09 mg/g). Verbascoside (phenylpropanoid) was the major compound identified in both extracts (11–25 mg/g). Regarding the carotenoid composition, all-trans-lutein (14–42 μg/g) and all-trans-β-carotene (13–44 μg/g) were the major compounds in both extracts. The high content of phenolic compounds and carotenoids in pulp + skin extract might explain its higher scavenging capacity against all the ROS/RNS as compared to seed extract. In general, both extracts showed better scavenging capacity for the RNS than for the ROS. Our results indicate that C. solanaceum fruits can be explored as an important natural source of antioxidant compounds.     

Phenolic composition,antioxidant and antimicrobial activities of free and bound phenolic extracts of Moringa oleifera seed flour

Phenolic compounds, antioxidant and antibacterial activities of defatted Moringa oleifera seed flour (DMF) were investigated. The total phenolic and flavonoid contents were measured using colorimetric methods. Free phenolic acid and flavonoid profiles were analyzed by high performance liquid chromatography, while antioxidant capacities were evaluated using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power and total antioxidant capacity. The results showed that extractability of phenolic compounds was significantly higher (p < 0.05) in bound phenolic extract (4173.00 ± 32.22 mg gallic acid equivalents (GAE)/100 g) than in free phenolic extract (780.00 ± 14.2 mg GAE/100 g) and it showed higher antioxidant and antimicrobial activities. The IC₅₀ value for DPPH radical scavenging activity was 0.9 ± 0.05 and 14.9 ± 0.07 mg/mL for bound phenolic and free phenolic extracts, respectively. Bound phenolic extract was more effective (minimum inhibitory concentration (MIC), 0.06–0.157%) than free phenolic extract (MIC, 0.117–0.191%) against tested bacteria. Ten phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, caffeic acid, protocatechuic acid, cinnamic acid, catechin, epicatechin, vanillin and quercetin) were identified and quantified in both extracts. These natural plant phenolics from Moringa seeds could be a good source of antioxidants and antibacterials for food and pharmaceutical industries.     

Sequential high pressure extractions applied to recover piceatannol and scirpusin B from passion fruit bagasse

Passion fruit seeds are currently discarded on the pulp processing but are known for their high piceatannol and scirpusin B contents. Using pressurized liquid extraction (PLE), these highly valuable phenolic compounds were efficiently extracted from defatted passion fruit bagasse (DPFB). PLE was performed using mixtures of ethanol and water (50 to 100% ethanol, w/w) as solvent, temperatures from 50 to 70 °C and pressure at 10 MPa. The extraction methods were compared in terms of the global yield, total phenolic content (TPC), piceatannol content and the antioxidant capacity of the extracts. The DPFB extracts were also compared with those from non-defatted passion fruit bagasse (nDPFB). Identification and quantification of piceatannol were performed using UHPLC–MS/MS. The results showed that high TPC and piceatannol content were achieved for the extracts obtained from DPFB through PLE at 70 °C and using 50 and 75% ethanol as the solvent. The best PLE conditions for TPC (70 °C, 75% ethanol) resulted in 55.237 mg GAE/g dried and defatted bagasse, whereas PLE at 70 °C and 50% ethanol achieved 18.590 mg of piceatannol/g dried and defatted bagasse, and such yields were significantly higher than those obtained using conventional extraction techniques. The antioxidant capacity assays showed high correlation with the TPC (r > 0.886) and piceatannol (r > 0.772). The passion fruit bagasse has therefore proved to be a rich source of piceatannol and PLE showed high efficiency to recover phenolic compounds from defatted passion fruit bagasse.     

Jaboticaba Pomace Powder Obtained as a Co-product of Juice Extraction: A Comparative Study of Powder Obtained from Peel and Whole Fruit

This study presents the evaluation of an emergent co-product generated during the production of jaboticaba juice by steam drag: the jaboticaba pomace. A comparison of physicochemical, technological and morphological properties of the jaboticaba powders obtained from the pomace, from the whole fruit and from the peel was performed. All the powder samples underwent the same processing: freeze-drying, milling and sieving. The powders appeared reddish, with an average diameter of approximately 64.83–103.51 μm and pH values of 3.45–3.74, water activity of 0.3133–0.3270, water holding capacity of 2.63–4.28 g H₂O/g and oil holding capacity of 2.79–2.98 g oil/g. Differential scanning calorimetry analysis showed that the endothermic peak temperature was 158.9–164.4 °C. Proximate composition analysis showed a large amount of total dietary fibre and insoluble dietary fibre in jaboticaba pomace (20.54 and 16.42 g/100 g, respectively), while jaboticaba peel had a good amount of soluble dietary fibre (10.72 g/100 g). Jaboticaba pomace had a large quantity of phenolic compounds (43.39 mg GAE/g d.w.), especially monomeric anthocyanin (3.92 mg cyanidin-3-glucoside/g d.w.), compared to the whole fruit. Jaboticaba pomace is valuable due to its high phenolic content (2.5 times higher than the whole fruit) and total dietary fibre content (2.2 times higher than the whole fruit). The results obtained in this study reinforce the idea that this co-product could be re-used in the development of functional ingredients and show that the industrialisation of these materials is one possible alternative for food diversification. Pomace powder could be added to many types of foods, such as cereals, snacks, drink mixes, and breads, or could be used for pharmaceuticals, such as slow-release antioxidants in packaging films.     

Pressurized aqueous ethanol extraction of β-glucans and phenolic compounds from waxy barley

Beta-glucans and phenolics were extracted from waxy barley using pressurized aqueous ethanol in a stirred batch reactor at 25 bar and 500 rpm. The effect of temperature (135–175 °C), extraction time (15–55 min) and ethanol content (5–20%) was evaluated. Temperature had an opposite effect on the extraction of both compounds. The higher the temperature, the lower the β-glucan extraction yield due to fragmentation, but a significant increase on the phenolic recovery was observed. Long extraction times favored the extraction of β-glucans at low temperatures and phenolics at any temperature. The ethanol content was not statistically significant on the β-glucan extraction, but helped to maintain the molecular weight of the extracted β-glucan. To obtain liquid extracts rich in high molecular weight β-glucans and phenolics, mild conditions of 151 °C, 21 min and 16% ethanol are needed, leading to 51% β-glucan extraction yield with a molecular weight of 500–600 kDa and 5 mg GAE/g barley.     

Comparison of different methods for extracting polyphenols from Ipomoea batatas leaves,and identification of antioxidant constituents by HPLC-QTOF-MS2

This study aimed to compare the extraction efficiency of dynamic high pressure microfluidization-assisted extraction (DHPMAE) and other commonly used extraction methods on the antioxidant activities (AAs) of sweet potato leaves (Ipomoea batatas L., SPL), and to identify the antioxidant compounds by HPLC-QTOF-MS². Two highly consumed commercial varieties, orange-fleshed and cream-fleshed sweet potato leaves (OFL and CFL), were taken as materials. OFL was evidenced to be a better antioxidants resource than CFL due to higher polyphenols and AAs. DHPMAE had the best extraction efficiency on total phenolics and total flavonoids, with the values in OFL extract at 16.35 mg GAE/g DM and 16.51 mg RE/g DM, respectively. DHPMAE extract also exhibited the strongest DPPH· and ABTS·⁺ scavenging ability, chelating ability and reducing power. Multiple regression analysis revealed that polyphenols played an important contribution to the AAs of SPL extracts. After successive fractionation of DHPMAE extract by chloroform, ethyl acetate, and n-butanol, the ethyl acetate fraction showed the highest total phenolic (569.38 mg GAE/g Extract) and total flavonoid (43.15 mg RE/g Extract) content, as well as the highest AAs. HPLC-QTOF-MS² analysis of the ethyl acetate fraction resulted in identifying 37 compounds including 20 phenolic acids, 12 flavonoids, 3 organic acids, 1 nucleoside and 1 ester, and 20 of them were firstly detected in SPL. Caffeoylquinic acid derivatives and flavonoids were the most abundant antioxidant compounds. The presented results suggested that DHPM might be a promising assisted technology in extracting polyphenols from plants, and SPL could be utilized for the development of functional food.     

Phenolic profile and antioxidant properties of a crude extract obtained from a brewery waste stream

The main aims of this study were to determine the phenolic profile of a crude extract obtained (at pilot scale) from a brewery waste stream and to evaluate the antioxidant activity of the extract. The total phenolic content was determined by the Folin–Ciocalteu assay, which revealed that 50% of the extract comprised phenolic compounds. The polyphenols, identified and quantified by RP-HPLC–DAD and HPLC-ESI–TOF-MS, were mainly flavonoids (catechin, epicatechin, gallocatechin, epigallocatechin, quercetin) and phenolic acids (ferulic acid, p-coumaric acid, caffeic acid, protocatechuic acid). The crude extract displayed a high DPPH radical scavenging activity (0.18 g/L), similar to that of BHA (0.248 g/L) and higher than that of BHT (2.54 g/L). All three tested products displayed a similar ability to decrease oxidative bleaching of β-carotene (antioxidant activity coefficient of 623.8 for the crude extract, 653.3 for BHA, 559.6 for BHT). This type of brewery waste stream may be a promising source of natural antioxidants to replace the synthetic antioxidants currently used in the food industry.     

Temperature-dependent kinetics of grape seed phenolic compounds extraction: Experiment and model

The kinetics of a batch solid–liquid extraction of total phenolic compounds (PC) from milled grape seed (Vitis vinifera L. cv. “Frankovka”) using 50% ethanol at different extraction temperatures (25–80 °C) was studied. The maximum yield of PC was 0.13 kg_GAE/kg_db after 200 min of extraction in agitated vessel at 80 °C. A new model based on the assumptions of a first order kinetics mechanism for the solid–liquid extraction and a linear equilibrium at the solid–liquid interface was developed. The model involves the concept of broken and intact cells in order to describe two successive extraction periods: a very fast surface washing process followed by slow diffusion of phenolic compounds from grape seeds to the solvent.The proposed model is suited to fit experimental data and to simulate the extraction of phenolic compounds, which was confirmed by the correlation coefficient (r ? 0.965), the root mean square error (RMSE ? 0.003 kg_GAE/kg_db) and the mean relative deviation modulus (E ? 2.149%). The temperature influenced both equilibrium partition coefficients of phenolic compounds and transport properties, which is manifested by a relatively high value of activation energy (23–24) kJ/mol and by values of effective diffusivity in seed particles.     

Ultrasound-assisted enzyme catalyzed hydrolysis of olive waste and recovery of antioxidant phenolic compounds

The ultrasound-assisted enzyme hydrolysis (UAEH) procedure for extraction of phenolics from olive waste (OW) was established. The optimized conditions obtained with response surface methodology (RSM) were pH 5.75, treatment 40 min and temperature 55 °C, the yield obtained reached to 4.0%. The extraction kinetics model was fitted well to the ln (C_t/C₀) = kt, and the rate constants (k) increased with the increased in the extraction temperature. Moreover, the values of k were higher and the activation energy was lower than ultrasound treatment alone. The thermodynamic parameters indicated the extraction process was easier under the UAEH. Compared with the petroleum ether and n-butyl alcohol, ethyl acetate extract fraction had high phenolic content (64.4 mg/g), especially hydroxytyrosol and tyrosol (17.2 mg/g and 14.1 mg/g), and exhibited excellent antioxidant activities in DPPH·, ABTS⁺·and FRAP assay. These finding revealed that OW could be used for a enrich source of natural phenolic compounds for development of food industry.Industrial relevanceOlive waste (OW) has been widely paid attention as sources of high-added value compounds, such as phenolic which can be obtained by the several methods. And phenolic extract as a food additive can not only improve the sensory quality of food, but also can enhance antioxidant capacity in fatty food matrices. Moreover, the use of this extract has better economic benefits than synthetic additives usually used in food industry. In this study, a novel green, simple and efficient technology was employed to extract the phenolic compounds, which was suitable for large-scale industrial use. The results indicated that ultrasound-assisted enzyme hydrolysis (UAEH) has significant potential in the extraction process of phenolics from OW exhibiting higher phenolic yield in shorter extraction times.     

Triticale bran and straw: Potential new sources of phenolic acids,proanthocyanidins, and lignans

The distribution of phenolic acids (free and bound), proanthocyanidins, and lignans in defatted triticale bran and straw was determined. For comparison, wheat, rye and oat brans as well as triticale flakes and leaves were also assayed. Most phenolic acids were present in the bound form (89–98%), and released under alkaline extraction conditions. The content of phenolic acids ranged from 65.2 to 252.5 mg/100 g in samples in which ferulic acid predominanted. Triticale straw was the richest source of proanthocyanidins, containing 862.5 mg/100 g (catechin equivalents) of tissue. Triticale straw contained 0.27 mg/100 g of lignan secoisolariciresinol diglucoside (SDG), whereas the bran had only 0.01 mg/100 g. The oxygen radical absorbance capacity (ORAC, μM Trolox equivalents/g defatted material) showed that antioxidant activity of bound phenolics was higher than those of free phenolics. This is the first report on phenolic acids, proanthocyanidin, and lignans content of Canadian triticale by-products, indicating that they may have the potential for use as nutraceuticals and/or functional food ingredients.     

Bean cultivars (Phaseolus vulgaris L.) have similar high antioxidant capacity,in vitro inhibition of α-amylase and α-glucosidase while diverse phenolic composition and concentration

Common beans are a good source of essential nutrients such as protein, fiber, vitamins, and minerals; they also contain phenolic compounds and other phytochemicals. Phenolic compounds exhibit high antioxidant capacity that promotes health benefits by reducing oxidative stress. The objective was to compare the composition and quantity of anthocyanins and other non-colored phenolic compounds in fifteen improved bean cultivars from Mexico and Brazil and their relation to antioxidant capacity and enzymes related to type-2 diabetes. Samples were analyzed for total phenolic compounds (TP), flavonoids, antioxidant capacity (AC), tannins and total anthocyanins. Type and quantity were evaluated by HPLC-ESI-MS. Delphinidin glucoside (0.9–129.0 mg/100 g dry coat), petunidin glucoside (0.7–115.0 mg/100 g dry coat) and malvidin glucoside (0.14–52.0 mg/100 g dry coat). Anthocyanidins were positively correlated when quantified by HPLC and colorimetric analysis (R = 0.99). Cultivar Negro-Otomi presented the highest concentration of anthocyanins (250 mg/100 g dry coat). Seventeen non-colored phenolic compounds were identified among cultivars; catechin, myricetin 3-O-arabinoside, epicatechin, vanillic acid, syringic acid and o-coumaric acid, presented the highest concentrations among identified phenolic compounds. The AC of all fifteen bean cultivars did not show significant differences (p > 0.05) ranging from 185.2 (FM-67) to 233.9 (FM-199) mmol TE/g coat. Compounds in the coat extracts of pinto and black cultivars were the most efficient to inhibit α-amylase and α-glucosidase. Studied cultivars differed in composition and concentration of phenolics including anthocyanins; however, there was no effect on AC as measured by oxygen radical absorbance capacity. Black beans contained delphinidin and ferulic acid, compounds commonly used as ingredients in functional foods due to their associated health benefits.     

Subcritical water extraction of phytochemicals from Phlomis umbrosa Turcz

Subcritical water extraction (SWE) avoids the use of organic solvents when extracting active compounds. The SWE of phytochemicals from Phlomis umbrosa Turcz (PT) and the effect of antioxidant activity were investigated while varying the extraction temperature (from 100 °C to 200 °C) and time (from 5 to 25 min). The maximum yields of total polyphenols (142.02 ± 5.67 mg/g PT, mean ± SD) and flavonoids (33.69 ± 3.01 mg/g PT) were obtained for an extraction temperature and time of 200 °C and 20 min, respectively. The correlation of antioxidant activities in terms of their total phenolics and flavonoids contents suggest that the ABTS⁺ assay better reflects the antioxidant contents in SWE from PT than does the DPPH assay for extraction temperatures from 110 °C to 200 °C. At higher temperatures around 200 °C, SWE extracts affect the antioxidant activity due to the presence of not only flavonoids but also nonflavonoid phenolic compounds including prenylated flavonoids.Industrial relevanceThis study used subcritical water extraction (SWE) for the practical applications of the SWE process that extracts antioxidant compounds from medicinal herb such as Phlomis umbrosa Turcz. SWE is excellent technology to selectively extract bioactive compounds using temperature-dependent dielectric constant properties of water. As the temperature of water is increased, the polarity of water decreases. That's why it is selective extraction. The use of SWE in the present study was associated with high efficiency and antioxidant activities. These results indicate that SWE is an efficient and rapid method for extracting phytochemicals, and a safer product only using purified water. SWE has a potential to develop a commercial process for the extraction of phytochemicals. This method can be easily implemented on an industrial scale.     

Improving the pressing extraction of polyphenols of orange peel by pulsed electric fields

The influence of pulsed electric field (PEF) treatment on the extraction by pressing of total polyphenols and flavonoids (naringin and hesperin) from orange peel was investigated. A treatment time of 60 μs (20 pulses of 3 μs) achieved the highest cell disintegration index (Zp) at the different electric field strengths tested. After 30 min of pressurization at 5 bars, the total polyphenol extraction yield (TPEY) increased 20%, 129%, 153% and 159% for orange peel PEF treated at 1, 3, 5 and 7 kV/cm, respectively. A PEF treatment of 5 kV/cm to the orange peels increased the quantity of naringin and hesperidin in the extract of 100 g of orange peels from 1 to 3.1 mg/100 g of fresh weigh (fw) orange peel and from 1.3 to 4.6 mg100 g fw orange peel respectively. Compared to the untreated sample, PEF treatments of 1, 3, 5 and 7 kV/cm increased the antioxidant activity of the extract 51%, 94%, 148% and 192%, respectively.The results of this investigation demonstrate the potential of PEF as a gentle technology to improve the extraction by pressing of polyphenols from fresh orange peel. This procedure enhances the antioxidant capacity of the extracts, reduces extraction times and does not require using organic solvents.Industrial relevanceProcessing of orange fruits to obtain fresh juice or citrus-based drinks generates very large amounts of byproduct wastes, such as peels that are a rich source of polyphenols mainly flavonoids. Extraction of these compounds from orange peels is a crucial step for use of these compounds in the food and pharmaceutical industries as antioxidants. PEF-assisted extraction by pressing of polyphenols from fresh orange peels stands as an economical and environmentally friendly alternative to conventional extraction methods which require the product to be dried, use large amounts of organic solvents and need long extraction times.     

Phenolic composition,caffeine content and antioxidant capacity of coffee silverskin

Coffea arabica silverskin (CSS), the inner fruit layer surrounding coffee beans, was analyzed for its (poly)phenolic and caffeine content by means of liquid chromatography–tandem mass spectrometry and evaluated for its antioxidant properties by means of the Folin–Ciocalteu and FRAP methods. The most abundant quantified phenolics were caffeoylquinic acids, with the 5- and 3-isomers being the most relevant (199 mg/100 g and 148 mg/100 g, respectively). The three caffeoylquinic acid isomers reached a total concentration of 432 mg/100 g, corresponding to 74% of the total chlorogenic acids detected in CSS. The level of the three feruloylquinic acids detected was 143 mg/100 g, corresponding to 23%, and the two identified coumaroylquinic acids plus the two caffeoylquinic acid lactones were only marginally contributing to the final figure (only 3% of total hydroxycinnamates). No unconjugated phenolic acid was detected. Caffeine content in CSS was equal to 10 mg/g of product, 3.5 times lower than most coffee brews. The total antioxidant capacity (TAC) of CSS was 139 mmol Fe^2 +/kg, a value similar to those of valuable sources of food antioxidants like dark chocolate, herbs and spices. Besides its potential as a food supplement, CSS may represent an innovative functional ingredient exploitable to increase the TAC of a wide range of food products.     

Glycine max (L.) Merr., Vigna radiata L. and Medicago sativa L. sprouts: A natural source of bioactive compounds

The consumption of sprouts, common in Asia, has been growing in western countries, once they are a natural healthy food and considered as a valuable dietary supplement. Comparing with their mature counterparts, sprouts are usually richer in health-promoting phytochemicals. So, the nutritional composition and the biological potential of widely consumed sprouts of three species – Glycine max (L.) Merr., Vigna radiata L. and Medicago sativa L. – were compared for the first time. Phenolic compounds and phytosterols were analyzed by HPLC–DAD and organic acids by HPLC–UV. The volatile profile was determined by HS-SPME/GC–IT/MS. Fourteen phenolic compounds (including four isoflavones), three sterols one triterpene, sixteen fatty acids, seven organic acids and thirty volatile compounds were determined. The antioxidant activity was assessed against DPPH^?, superoxide and nitric oxide radicals. G. max sprouts were the most active against DPPH^? (IC₅₀ = 1.337 mg/mL), while those of M. sativa were the most effective against superoxide and nitric oxide radicals (IC₅₀ = 67 μg/mL and IC₅₀ = 426 μg/mL, respectively). Data provide evidence of great similarities between G. max and M. sativa sprouts, both being rich in phenolic compounds, fatty acids and volatiles, and exhibiting better antioxidant activity. On the other hand, V. radiata showed higher amounts of sterols, triterpenes and organic acids. In this study it was found that the sprouts are a good source of bioactive compounds in our diet with health-promoting antioxidants.     

Optimization of the enzymatic treatment during aqueous oil extraction from sunflower seeds

Partially dehulled sunflower seeds were subjected to a hydrolytic treatment with cellulases during aqueous processing for oil and protein extraction. Sub-optimal extraction conditions (particle size and separation technology) were established in order to appreciate the potential improvement caused by the enzymatic treatment and to select the best operational conditions. The effects of three operational variables (extraction–treatment time, water/seeds ratio and enzyme/seed ratio) were studied on three objective functions (the extent of hydrolysis reaction, the oil extraction yield and the percent polyphenolics removal). After 2 h of enzymatic treatment–extraction a practical optimum in the range 7.5–8 g water g⁻¹ seeds and 1.25–1.4 g enzyme 100 g⁻¹ seeds could be defined. Under these conditions the oil extractability and the polyphenolics removal are improved by more than 30 and 80%, respectively.