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19 Páginas.-- 5 Figuras.-- 5 Tablas, The phytochemical composition of leaves, stems, pericarps and rhizomes ethanolic extracts of Asparagus acutifolius were characterized by HPLC-DAD-MS. A. acutifolius samples contain at least eleven simple phenolics, one flavonon, two flavonols and six steroidal saponins. The stem extracts showed the highest total phenolic acid and flavonoid contents, where cafeic acid and rutin were the main compounds. No flavonoids were detected in the leaf, pericarp or rhizome while caffeic acid and ferulic acid were the predominant. Steroidal saponins were detected in the different plant parts of A. acutifolius, and the highest contents were found in the rhizome extracts. The stem extracts exhibited the highest antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) and the highest 2,2-azino-bis (3 ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging activity was found in the pericarp extracts. The rhizome and leaf extracts showed a potent cytotoxic activity against HCT-116 and HepG2 cell lines. Moreover, the pericarp and rhizome extracts revealed a moderate lipase inhibitory activity. The leaf and rhizome extracts were screened for their antimicrobial activity against human pathogenic isolates. The leaf extract exhibited a powerful inhibitory activity against all the bacteria and fungi tested., This research was funded by the Tunisian Ministry of Scientific Research and Technology and by the Ministerio de Ciencia e Innovación of Spain (AGL2017-82428-R).

11 Páginas.-- 6 Figuras.-- 3 Tablas, In Algeria, Fraxinus angustifolia Vahl (Oleaceae) is a prominent ingredient for the treatment of inflammatory diseases caused by oxidative stress. This study aimed to make a comparison between the phenolic compound compositions of the ethanolic and aqueous extracts (decoction and infusion) of this plant and to test the antioxidant, cytotoxic and anti-pancreatic lipase activities of the ethanolic extracts from the leaf and bark. The identification and quantification of phenolic compounds was carried out by HPLC-DAD-MS and the antioxidant activity was assessed according to three methods: Ferric Reducing Antioxidant Power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical scavenging activity and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging activity. The cytotoxic effect was investigated using the human colon adenocarcinoma cell line HCT-116; while pancreatic lipase inhibitory activity was examined using 4-nitrophenyl butyrate (NPB) as a substrate. A large variety of phenolic compounds were detected and the content of the leaf was much higher than that of the bark. The ethanolic extracts from the leaf had a higher antioxidant capacity than those of the bark, however, the latter showed greater antilipase activity and cytotoxicity than the former. These results suggest that this plant may be an important source of active compounds with a variety of biological activities which justify its use in traditional medicine., This work was supported by the Spanish Ministry of Science and Innovation (AGL2017-82428-R).

The aim of this work was to study the saponin profiles from spears of different wild asparagus species in the context of its genetic diversity aside from geographical seed origin. They included Asparagus pseudoscaber Grecescu, Asparagus maritimus (L.) Mill., Asparagus brachiphyllus Turcz., Asparagus prostrates Dumort., and Asparagus officinalis L. The saponin analysis by LC-MS has shown that saponin profile from wild asparagus is similar to that previously described for triguero asparagus from Huetor-Tajar landrace (triguero HT), which had not ever been reported in the edible part of asparagus. All the samples, except A. officinalis, were characterized for having saponins distinct to protodioscin and the total saponin contents were 10-fold higher than those described for commercial hybrids of green asparagus. In particular, A. maritimus from different origins were rich in saponins previously found in triguero HT. These findings supported previous suggestion, based on genetic analysis, about A. maritimus being the origin of triguero HT. Multivariate statistics including principal component analysis and hierarchical clustering analysis were used to define both similarities and differences among samples. The results showed that the greatest variance of the tested wild asparagus could be attributed to differences in the concentration of particular saponins and this knowledge could be a tool for identifying similar species.

32 Páginas; 7 Tablas; 3 Figuras, Soluble dietary fiber (SDF) has got increasing interest because of its prebiotic effects and technological applications. The enzymatic hydrolysis is an effective treatment to convert insoluble dietary fiber (IDF) into SDF. Date fiber concentrate (DFC) is a very good source of dietary fiber, but its IDF/SDF ratio is very high. In this study an enzymatic treatment has been optimized to enrich DFC in SDF: Viscozyme® L from Novozymes A/S at 2.38 mL enzyme/100 mL reaction volume, in a solid/liquid ratio 1 g/35 mL, at 55 °C during 30–60 min. In these conditions, the amount of SDF increased from 1.8–6.3 to 5.4 g/100 g, and the ratio IDF/SDF changed from 19 to 2–3. In the SDF, besides an increase in the antiradical activity, gluco-, manno-, and xylo-oligosaccharides have been identified. Their molecular weights varied in a wide range, depending of hydrolysis duration, which suggests that this enzymatic treatment could be a promising process for obtaining tailor-made prebiotic oligosaccharides., This research was supported by the Banq Islamique de Développement BID (Saudi Arabia) REF. 36/11201707

33 Páginas; 5 Tablas; 4 Figuras, Asparagus by-products were submitted to hydrothermal treatments to improve their solubility and antioxidant capacity. Four severity conditions were applied (logRo 3.05, 3.64, 4.23, 4.82) and two fractions were isolated from each treatment. The solid fibrous residues were enriched in cellulose, and depleted of hemicelluloses and phenolics. Their antioxidant activities were higher than those presented for asparagus bioactive fibers (81–154 vs 21–26 mmol Trolox/Kg) and did not correlate with phenol content. The soluble liquors were rich in phenolics and also contained changeable amounts of mono-, oligo-, and polysaccharides as a function of severity. The majority of the released oligosaccharides (xylooligosaccharides) are considered as prebiotic and their percentage could be optimized by modifying hydrothermal treatment conditions. This fraction presented very high antioxidant activity (131–232 mmol Trolox/Kg), and had a moderate correlation with phenols. Melanoidins are suggested to be present in both fractions. A new fiber fraction with potential prebiotic activity and high antioxidant activity has been obtained from asparagus by-products. Its high solubility in water and a pleasant flavor broaden its applications in food formulations., This research was supported by the project AGL2017-82428-R from MINECO, Spanish Government.

Asparagus cultivation and consumption are widely spread throughout the world. Several investigations about fresh asparagus have evidenced that they are a nutritionally well-balanced and one of the best sources of antioxidants being the green spears richer than the white ones. However, there is scarce information on quality of canned asparagus. In the present work, we have studied chemical and phytochemical composition of 21 distinct presentations of asparagus, representative of the distinct brands available in Spanish markets. Our results revealed that this appreciated product continued to be of high nutritional quality after industrial processing, containing 1-1.8% bioactive fiber and 1-3% proteins. In addition, it contained significant quantities of several bioactive compounds, mainly ascorbic acid (6-12 mg/100g) and phenolics that in green asparagus ranged 16-46 mg/100g. Asparagus variety seems to be the factor that most influence the composition and quality of the final product. There were two samples of green asparagus that stand out from all others and that correspond to triguero asparagus from southern Spain. It can be concluded that the selection of varieties taking into account not only agronomic factors, but also phytochemical profile is determinant to obtain a product of the highest quality for both fresh and processed commercialization., This work was supported by the the Ministerio de Ciencia e Innovación of Spain (AGL2011-29632).

Glucosinolate extracts from sprouts of common Brassica nigra, B. juncea cv. Scala, B. carinata cv. Eleven, and Sinapis alba cv. Ludique were analysed by reversed phase high-performance liquid chromatography-diode array detection-mass spectrometry. The effect of the glucosinolate–myrosinase system on in vitro mycelial growth of Phytophthora cinnamomi Rands and Pythium spiculum B. Paul was assessed. Likewise, sinigrin and sinalbin monohydrate commercial standards were also tested. The extracts from B. carinata, which contained 159 mmol/g plant DW equivalent (85% sinigrin, 5% gluconapin, and 3% glucotropaeolin), were the most effective against Phytophthora and Pythium isolates used in this study. However, the extract from S. alba, which contained 1 180 mmol/g (100% sinalbin), did not inhibit the mycelial growth of the isolates tested. The use of the glucosinolate-myrosinase system provides important additional information to advance in the implementation of field application of brassicaceous amendments for the control of soil-borne pathogens.

Secondary varieties of date from Tunisia are underutilized due to their low commercial quality. Fiber concentrates (DFC) can be obtained from these fruits after a steam pretreatment. DFCs were evaluated as a source of antioxidant dietary fiber for bakery products. Muffins were prepared with 2.5 and 5% flour substitution with DFCs obtained by treatments at 165 and 180C. The DFC-doughs presented a similar yield to the control but the muffins reached a lower volume. The density increase did not imply an increase in texture. In fact, the muffins with DFC-165 were the softest tested, although they had lower cohesiveness and springiness. The proximate composition was similar among samples. The DFC-muffins had higher antioxidant capacity than the control, and obtained good scores in the sensory evaluation. DFC-165 is a valuable ingredient for baked goods, but its effect on fat rancidity and staling delays should be confirmed. Practical Applications Listing dietary fiber on the ingredient label of a product is always viewed positively by consumers. Several dietary fibers coming from underutilized varieties of Tunisian dates were added to bakery products. In some cases, texture and organoleptic characteristics of fortified muffins were the best tested, increasing also their antioxidant activity. From a technological point of view, the addition of date dietary fiber could also extend the self-life of baked goods due to a delay of staling and fat rancidity caused by storage.

3 Figuras.-- 1 Tabla, Colorectal cancer is the third most common cancer in the world. Many efforts have focused on finding natural molecules with potential chemo-preventive activity due to their low toxicity compared to synthetic drugs. However, comprehensive information on the bioactive fractions and components is still missing. In this study, we developed a method for the quantitative separation and isolation of saponins from asparagus genotypes consisting of an adsorption chromatography and subsequent liquid chromatographic separation on a reversed-phase column. The saponins isolated were tested for their cytotoxic activity against human colon cancer cell lines, which could develop cross-resistance to a wide variety of chemotherapeutic drugs. Our results showed that Huétor-Tájar asparagus saponins (HTSAP), mainly protodioscin and HTSAP-10 have higher cytotoxic activity than HTSAP-1, HTSAP-6, and HTSAP-8. This study links the potential anticancer effect of asparagus to specific saponins and unveils the triguero Huétor-Tájar asparagus as a nutraceutical particularly in colon cancer therapies., Sergio López acknowledges the financial support from the Spanish MINECO (JCI‐2012‐13084, Juan de la Cierva, MINECO) and the ‘V Own Research Plan’ of the University of Seville (VPPI‐US) for his research contracts. These contracts are cofunded by the European Social Fund.

27 páginas; 4 tablas; 2 figuras, Two hydrothermal treatments were assayed on secondary date varieties from the Tunisian coastal oasis in order to obtain valuable solid extracts, rich in dietary fiber and antioxidants. The steam explosion treatment (SET) is based on high temperatures and pressures, with an explosive decompression. The steam treatment (ST), without rapid decompression, has lower pressures and temperatures, but longer treatments than SET. The recovery of the fiber concentrates (FCs) was very similar for the different assayed conditions. Only its granulometry showed differences, increasing the fraction with size lower than 4 mm in more intense treatments. Treatment conditions had higher influence than date variety in the FCs chemical composition. It was approximately 0.1–2% soluble sugar, 0.7–2% uronic acids, 4–8% phenols, 5–11% fat, 5–22% non-cellulosic sugars, 9–14% protein, 12–20% cellulose, and 44–71% lignin, depending on treatment conditions. They had also very high antiradical activity (230–580 mmols Trolox/Kg FC). The use of ST reactor is highly recommended because it could be easily scaled up to the industry. The FC obtained by hydrothermal treatments from date fruits could be considered as a very interesting ingredient for healthier food, especially for bakery or dairy products due to its pleasant chocolate/coffee flavor., This research was supported by the Ministerio de Asuntos Exteriores y Cooperación – Agencia Española de Cooperación Internacional para el Desarrollo MAEC-AECID REF. 550352 (Spain), and by the Banq Islamique de Développement BID (Saudi Arabia REF. 36/11201707).

5 Tablas.-- 3 Figuras, The ethanolic extracts from the leaves, pericarps and rhizomes of Asparagus albus L. were investigated for their phytochemical composition, antioxidant (DPPH and FRAP assays), anti-microbial against human pathogenic isolates and cytotoxic (human colon carcinoma HCT-116 cells) activities. The highest flavonoid content was obtained in the leaf extract followed by the pericarp but there were no flavonoids detected in the rhizome. However, the rhizome had a high concentration of saponins. Flavonoid and saponin profiles were similar to those previously described for the triguero Huetor Tajar asparagus landrace. It was found that the pericarp ethanolic extract exhibited higher antioxidant activity than rhizome and leaf extracts. Moreover, the rhizome possessed more evident cytotoxic activity against HCT-116 cells in comparison to leaf and pericarp. All extracts showed varying degrees of antimicrobial activity against most of the human pathogenic isolates. In addition, the leaves showed more powerful inhibitory activities against the maximum number of bacteria and all the fungai isolated and the highest activity was in the pericarp extract against multidrug resistant Pseudomonas aeruginosa (MDR) and Erythromycin resistant Streptococcus agalactiae (ER) with an inhibition zone of 21 mm and 19 mm, respectively. The results show that A. albus could be a new crop with pharmaceutical interest because its richness in bioactive compounds provides considerable benefits for human health., This work was supported by the Tunisian Ministry of Scientific Research and Technology and by the Ministerio de Ciencia e Innovación of Spain (AGL2011-29632). The authors are enormously grateful to Dr. Ilhem Boutiba Ben Boubaker (Antibiotic resistance laboratory, Faculty of Medicine of Tunisia) and Dr. Saadia Gargouri (Department of parasitology, Military Hospital of Tunis) for their assistance during the antimicrobial analysis and to Dr. Smaoui Abderrazek for botanical identification of the plants.

In the Nerpio region (Albacete, Spain), endogenous walnut cultivars have been grown since ancient times. None of them has been chemically characterized to valorize them in comparison to commercial varieties. In this work, 47 native (N) and 7 foreign (F) walnut cultivars grown in Nerpio, and 13 commercial (C) samples were studied during three seasons. The average yield, moisture, and protein and oil contents were slightly lower in the N samples than in C. The composition of fatty acid suggested that the N walnuts could be more stable against oxidation due to their higher amount of MUFA and lower amount of PUFA. The biological protein value for the samples was similar but the antioxidant capacity marked important differences among them: N cultivars reached the highest scores, with intermediate F values. Local walnut varieties from Nerpio should be valorized on the basis of their potentially enhanced health benefits, although further studies must be developed on their phytochemicals.

The main goal of this study was to determine the saponin profiles of different "triguero" asparagus genotypes and to compare them to green asparagus commercial hybrids. The samples consisted of 31 commercial hybrids and 58 genotypes from the Huétor-Tájar (HT) population variety ("triguero"). The saponin analysis by high-performance liquid chromatography-mass spectrometry allowed for the determination of 12 saponins derived from a furostan-type steroidal genin, 4 of which had never been described in the edible part of asparagus. The saponin profile of "triguero" asparagus was a combination of these new saponins and protodioscin. Although protodioscin was the major saponin found in commercial hybrids, some of these 12 saponins were detected as major components in some of the commercial hybrids. The total contents of saponins described in some of these HT genotypes reach values as high as 10-100 times higher than those found in commercial hybrids.

The main goal of this study was the optimization of a HPLC-MS method for the qualitative and quantitative analysis of asparagus saponins. The method includes extraction with aqueous ethanol, cleanup by solid phase extraction, separation by reverse phase chromatography, electrospray ionization, and detection in a single quadrupole mass analyzer. The method was used for the comparison of selected genotypes of Huétor-Tájar asparagus landrace and selected varieties of commercial diploid hybrids of green asparagus. The results showed that while protodioscin was almost the only saponin detected in the commercial hybrids, eight different saponins were detected in the Huétor-Tájar asparagus genotypes. The mass spectra indicated that HT saponins are derived from a furostan type steroidal genin having a single bond between carbons 5 and 6 of the B ring. The total concentration of saponins was found to be higher in triguero asparagus than in commercial hybrids.

The aim of this work was to study the saponin profiles from spears of different wild asparagus species in the context of its genetic diversity aside from geographical seed origin. They included Asparagus pseudoscaber Grecescu, Asparagus maritimus (L.) Mill., Asparagus brachiphyllus Turcz., Asparagus prostrates Dumort., and Asparagus officinalis L. The saponin analysis by LC-MS has shown that saponin profile from wild asparagus is similar to that previously described for triguero asparagus from Huétor-Tájar landrace (triguero HT), which had not ever been reported in the edible part of asparagus. All the samples, except A. officinalis, were characterized for having saponins distinct to protodioscin and the total saponin contents were 10-fold higher than those described for commercial hybrids of green asparagus. In particular, A. maritimus from different origins were rich in saponins previously found in triguero HT. These findings supported previous suggestion, based on genetic analysis, about A. maritimus being the origin of triguero HT. Multivariate statistics including principal component analysis and hierarchical clustering analysis were used to define both similarities and differences among samples. The results showed that the greatest variance of the tested wild asparagus could be attributed to differences in the concentration of particular saponins and this knowledge could be a tool for identifying similar species.

30 Páginas.-- 2 Figuras.-- 4 Tablas, The dietary fibers (DF) of 10 date varieties from Tunisian oases have been investigated. Further knowledge on the content, composition, and technological applications of those fibers could support their genetic variability and promote the socioeconomical development of growing areas. The composition, water- and oil-holding capacities, solubility, and antiradical activity have been determined. The DF content ranged from 4.7% (Matteta, Rochdi) to >7% (Deglé Nour, Garen Gaze, Smeti). Composition varied significantly among cultivars, and the results evidenced that uronic acids and lignin determine to a great extent the organoleptic quality of dates. Many of the varieties that have been studied (Garen Gaze, Matteta, Kenta, Rochdi, Mermella, Korkobbi, Eguwa) were selected because of great interest from technological and functional points of view. Among their physicochemical characteristics, these samples presented water- and oil-holding capacities of higher than 17 and 4 mL/g fiber, respectively, which make them suitable for use as additives in fiber-enriched foods. Also, DF of Garen Gaze, Smeti, Mermella, and Eguwa had a high antiradical capacity (>230 Trolox equiv/kg fiber). It was concluded that some of these varieties could be grown as potential sources of DF, which could be included in the formulation of fiber- and antioxidant-enriched foods. © 2012 American Chemical Society., We are grateful to the Institut des Regions Arides (Medenine, Tunisia) for the financial support of travel expenses of A.M. for his stay with the Instituto de la Grasa (Sevilla, Spain).

The determination of flavonoid profiles from different genotypes of triguero asparagus and their comparison to those from green asparagus commercial hybrids was the main goal of this study. The samples consisted of 32 commercial hybrids and 65 genotypes from the Huetor-Tajar population variety (triguero). The analysis of individual flavonoids by HPLC-DAD-MS has allowed the determination of eight naturally occurring flavonol derivatives in several genotypes of triguero asparagus. Those compounds included mono-, di-, and triglycosides of three flavonols, that is, quercetin, isorhamnetin, and kaempferol. The detailed analysis of the flavonoid profiles revealed significant differences among the distinct genotypes. These have been classified in three distinct groups as the result of a k-means clustering analysis, two of them containing both commercial hybrids and triguero asparagus and another cluster constituted by 21 genotypes of triguero asparagus, which contain several key flavonol derivatives able to differentiate them. Hence, the triglycosides tentatively identified as quercetin-3-rhamnosyl-rutinoside, isorhamnetin-3-rhamnosyl-rutinoside, and isorhamnetin-3-O-glucoside have been detected only in the genotypes grouped in the above-mentioned cluster. On the other hand, the compound tentatively identified as isorhamnetin-3-glucosyl-rutinoside was present in most genotypes of triguero asparagus, whereas it has not been detected in any of the commercial hybrids.

© 2014 American Chemical Society. Asparagus byproducts are a good source of cationic soluble peroxidases (CAP) useful for the bioremediation of phenol-contaminated wastewaters. In this study, cell wall bound peroxidases (POD) from the same byproducts have been purified and characterized. The covalent forms of POD represent >90% of the total cell wall bound POD. Isoelectric focusing showed that whereas the covalent fraction is constituted primarily by anionic isoenzymes, the ionic fraction is a mixture of anionic, neutral, and cationic isoenzymes. Covalently bound peroxidases were purified by means of ion exchange chromatography and affinity chromatography. In vitro detoxification studies showed that although CAP are more effective for the removal of 4-CP and 2,4-DCP, anionic asparagus peroxidase (AAP) is a better option for the removal of hydroxytyrosol (HT), the main phenol present in olive mill wastewaters., S.J.-C. and S.L. acknowledge financial support from the Spanish CSIC (JAE-doc Program), a contract cofunded by the ESF. S.V.-C. thank the Spanish CSIC for her contract (JAE Pre Program).

Soluble peroxidase (POD) from asparagus byproducts was purified by ion exchange chromatographies, and its kinetic and catalytic properties were studied. The isoelectric point of the purified isoperoxidases was 9.1, and the optimum pH and temperature values were 4.0 and 25 C, respectively. The cationic asparagus POD (CAP) midpoint inactivation temperature was 57 C, which favors its use in industrial processes. The Km values of cationic asparagus POD for H2O2 and ABTS were 0.318 and 0.634 mM, respectively. The purified CAP is economically obtained from raw materials using a simple protocol and possesses features that make it advantageous for the potential use of this enzyme in a large number of processes with demonstrated requirements of thermostable POD. The results indicate that CAP can be used as a potential candidate for removing phenolic contaminants. © 2013 American Chemical Society., S.J.-C. and S.L. acknowledge financial support from Spanish CSIC (JAE-doc Program), a contract cofunded by the ESF. S.V.-C. thanks Spanish CSIC for her contract (JAE Pre Program).

13 Páginas.-- 2 Figuras.-- 2 Tablas, We have previously shown that the Andalusian-cultivated Asparagus officinalis L. “triguero” variety produces hypocholesterolemic and hepatoprotective effects on rats. This asparagus is a rich source of phytochemicals although we hypothesized there would be some of them more involved in these functional properties. Thus, we aimed to study the effects of asparagus (500 mg/kg body weight (bw)/day) and their partially purified fractions in flavonoids (50 mg/kg bw/day), saponins (5 mg/kg bw/day) and dietary fiber (500 mg/kg bw/day) on oxidative status and on lipid profile in rats fed a cholesterol-rich diet. After 5 weeks treatment, plasma lipid values, hepatic enzyme activities and liver malondialdehyde (MDA) concentrations were measured. With the exception of the saponin fraction (SF), the administration of lyophilized asparagus (LA), fiber fraction (FF), and flavonoid fraction (FVF) to hypercholesterolemic rats produced a significant hypolipidemic effect compare to a high-cholesterol diet (HCD). In addition, the LA and FVF groups exhibited a significant increase in enzyme activity from multiple hepatic antioxidant systems including: superoxide dismutase, catalase, and gluthatione reductase/peroxidase as well as a decrease in MDA concentrations compared to HCD group. These results demonstrate that “triguero” asparagus possesses bioactive constituents, especially dietary fiber and flavonoids, that improve the plasma lipid profile and prevent hepatic oxidative damage under conditions of hypercholesterolemia., This study has been supported by funds from the “Comisión Interministerial de Ciencia y Tecnología” (Spanish CICYT) (Project AGL-2007-63703/ALI). The authors are grateful to the Food Biotechnology Group of the CSIC, Seville, Spain, for supplying the asparagus samples.

Asparagus (Asparagus officinalis L.) by-products, which represent around 50% of the processed vegetable, are a potential source of dietary fibre. The way that these by-products are treated affects the composition and functional properties of fibre-rich powders. Factors such as treatment intensity, solvent, and drying system were studied. Only the more soluble components (soluble sugars, uronic acids and proteins) showed significant differences. All the fibre-rich powders had high concentrations of TDF (62–77%). The IF/SF proportion decreased with the severity of treatment, in this way increasing the physiological quality of the fibre. Functional properties, namely water-holding capacity (WHC), oil-holding capacity (OHC), solubility (SOL), and glucose dialysis retardation index (GDRI), varied according to the preparation procedure. WHC and GDRI were higher in intensely extracted fibres; due to the effect of thermal processing. WHC showed values (11–20 ml water/g powder) similar to those described for other agricultural by-products, but OHC and GDRI were much higher (5–8 ml oil/g powder and 25–45%, respectively). These properties make fibre-rich powders from asparagus by-products a valuable source of dietary fibre to be included in the formulation of fibre-enriched foods., This research was supported by the Ministerio de Ciencia y Tecnología (Spain), Proyect PETRI PTR1995-0968-OP.

Asparagus (Asparagus officinalis L.) spears are highly appreciated for their composition of bioactive compounds. The method by which their by-products are treated affects the phytochemical composition and antioxidant activity of the fibre-rich powders. Factors such as the treatment intensity, the solvent used, and the drying system were studied. Among the asparagus phytochemicals, hydroxycinnamic acids (HCA), saponins, flavonoids, sterols, and fructans were quantified. HCA varied from 2.31 and 4.91 mg/g of fibre, the content being affected by the drying system and, in some cases, the solvent. Fibres from intense treatments had significantly higher amounts of saponin than samples isolated by gentle treatments. Saponin content ranged from 2.14 to 3.64 mg/g of fibre. Flavonoids were the most affected by processing conditions, being present (0.6–1.8 mg/g of fibre) only in three of the samples analysed. Continuous stirring during processing could be the main reason for this result. Sterols and fructans were present in minor amounts, 0.63–1.03 mg/g of fibre and 0.2–1.4 mg/g of fibre, respectively. Soluble and total antioxidant activities were also measured. Fibres with the highest activities corresponded to those with the highest levels of flavonoids and HCA., This research was supported by the Ministerio de Ciencia y Tecnología (Spain), Proyect PETRI PTR1995-0968-OP, and Centro Sur S.C.A. (Huétor-Tajar, Granada, Spain).

Previous studies on bioactive components of asparagus have revealed that the by-products are rich in many of the phytochemicals located in the edible part of the spears. The main components responsible of asparagus bioactivity are phenols (flavonoids and hydroxycinnamic acids) and saponins. We have developed a process for obtaining added-value compounds from asparagus by-products by the hydrothermal treatment of the samples. Two fractions are separated after the hydrothermal treatment, consisting on an aqueous functional extract containing most soluble bioactive compounds from asparagus by-product, and a fibrous residue that, after being dried, constitutes the asparagus bioactive fibre. The process includes a column purification step, using an adsorbent polymeric resin, which allows aqueous extracts, partially purified to be obtained and enriched in specific compounds (phenolics and/or saponins). All these presentations have been investigated for their biological activity. The preliminary results showed that the distinct products obtained from asparagus by-products are of interest for their biological activity and are suitable for being used as functional ingredients. Based on their antioxidant capacity, it could be proposed that their regular use could help the prevention of several diseases related to the oxidative damage.