Diminution of quinolizidine alkaloids,oligosaccharides and phenolic compounds from two species of Lupinus and soybean seeds by the effect of Rhizopus oligosporus

Lupinus, like Glycine max (soybean), is an ancient leguminous plant. It has been used as a food by people living around the Mediterranean Sea and in the Andean Highlands. This legume contains quinolizidine alkaloids (Qas), oligosaccharides (OGS) and phenolic compounds (PC). The objective of this study was to evaluate the effect of the growth of Rhizopus oligosporus on the levels of Qas, OGS and PC from L. mutabilis, L. campestris and G. max through tempeh elaboration. The results showed that the soaking and cooking processes of legume seeds diminished the Qas content of L. mutabilis and L. campestris by 50%, and after 48 h of fermentation these compounds decreased by more than 90% in total. OGS diminished by more than 90% in the lupin seeds. The PC content of the three seed species subjected to these processes increased their absorbance value, probably due to the enzymatic action of a fungal tannase. These results suggested that the L. mutabilis, L. campestris and G. max fermentation with R. oligosporus is an efficient method for diminishing antinutritional factors and for obtaining a product with optimal nutritional value. Copyright © 2007 Society of Chemical Industry     

Interactions between Lupinus angustifolius seeds lipoxygenase and native phenolic compounds in the model system

The aim of this study was to investigate the activity of lipoxygenase extracted from Lupinus angustifolius seeds and its interactions with native lupin polyphenols. The examinated enzyme is active at pH 7.5 causing peroxidation of linoleic acid. The main hydroperoxide produced in the presence of investigated lupin lipoxygenase was 13-hydroperoxy-octadecadienoic acid (13-HPODE t-t). In the presence of the phenolic compounds extracted from L. angustifolius seeds, the changes of lipoxygenase activity were observed. A distinct antioxidant effect of lupin polyphenols observed at their low concentration (0.58???g/ml) was almost completely overcome at higher concentration of phenolic compounds (2.91???g/ml). It comes probably from oxidation of polyphenols in the presence of lupin lipoxygenase. In this mechanism, polyphenol radical formation is possible. The formed radicals decrease the antioxidant efficiency of the phenolic compounds. Eventual phenoxyl radical-mediated peroxidation may be inhibited by the presence of antioxidants able to regenerate flavonoids.     

Production of a yogurt‐like product from Lupinus campestris seeds

A Lupinus campestris milk‐like product was obtained with 6.3% protein by using an alkaline thermal treatment. The colour of the suspension showed a greater similarity to cow's milk than to commercial soymilk. To adjust the carbohydrate concentration and induce fermentation, 3% of sucrose and 1.5% of lactose were added. The product was pasteurized and inoculated with a culture of Streptococcus thermophilus and Lactobacillus delbrueckii ssp bulgaricus. A lupin yogurt‐like product with pH 4.02, 0.87% lactic acid, and a lactic acid bacteria count (3.2 × 10⁸ CFU ml^?1) and viscosity similar to commercial cow's milk yogurt was obtained. The amino acid composition of the proteins in the lupin milk and yogurt products had a good balance, with the exception, as in other legumes, of the sulphur‐containing amino acids. Sensory evaluation indicated that the product was well accepted by consumers. These results offer a good possibility for the utilization of this legume in human nutrition through the elaboration of products that are analogous to others already present in the commercial market. Copyright © 2003 Society of Chemical Industry     

Antioxidant activity of phenolic compounds identified in sunflower seeds

The antioxidant activity and phenolic compound profiles of six fractions (I–VI) obtained from sunflower seed extract were studied. HPLC–MS(ESI) analysis was applied for quantitative and qualitative determination of phenolic compounds of the fractions. The antioxidant activity of the fractions was studied in terms of their ability to scavenge DPPH^· and ABTS^·+ and to reduce Fe³⁺/ferricyanide complex to the ferrous form and was expressed as EC₅₀, TEAC and reducing power values, respectively. The results of all antioxidant activity tests showed good correlations among each other and with the phenolic contents for the individual fractions. The fractions IV–VI were characterized by high antioxidant activity. 5-O-Caffeoylquinic acid was a predominant compound of fractions IV and V, while dicaffeoylquinic acid isomers and caffeoyl-dimethoxycinnamoylquinic acid isomers accounted for 76.6 % of phenolic compounds of fraction VI. Ferulic acid, p-coumaroylquinic acid isomers, ferulic acid dehydrotrimer isomers and some quercetin derivatives were also identified. The highest content of those compounds was noted in fraction III.     

油茶饼中酚类化合物的抗氧化性研究

用异丙醇、正己烷、乙醚分别从油茶饼中提取酚类化合物,所得到的3种提取物中酚类化合物的含量分别为:764、105、276μg/mL。研究这3种酚类提取物的抗氧化活性,包括对DPPH·自由基、羟基自由基、超氧阴离子的清除作用,以及对Fe2+的络合能力和Fe3+的还原能力。结果表明,异丙醇提取物对DPPH自由基和羟基自由基的清除能力和对Fe3+的还原力极显著地大于正己烷提取物和乙醚提取物。而正己烷提取物对超氧阴离子有较强的清除能力,3种提取物对Fe2+的络合能力没有极显著性差异。说明油茶饼提取物有显著的抗氧化性,而异丙醇提取物的抗氧化活性较好。     

Antimutagenic activity of natural phenolic compounds present in the common bean ( Phaseolus vulgaris ) against aflatoxin B 1

Polyphenols with antimutagenic and anticarcinogenic properties are present in fruits, vegetables and legumes. In this study, the Salmonella typhimurium tester strains TA98 and TA100 were used in the microsuspension assay to examine the antimutagenic effect of phenolic compounds extracted from the common bean (Phaseolus vulgaris) against mutagenicity induced by aflatoxin B 1 (AFB 1 ). A dose-response curve was constructed for AFB 1 ; from which a level of 40ng AFB 1 /tube was selected for all antimutagenicity assays. The AFB 1 and phenolic extract (PE) were not toxic to the bacteria at concentrations tested. In the case of PE, results were similar to the number of spontaneous revertants for TA98 and TA100. The inhibitory effect of PE against AFB 1 mutagenicity was dose-dependent at the lower concentrations tested (2.5, 5, 10, 12.5, 15 and 25 μg-equivalent ( + )-catechin/tube for TA98; 0.5, 1, 1.5, 2.5, 5, 10 and 25 μg-equivalent ( + )-catechin/ tube for TA100). Further, a two-stage incubation procedure was used to investigate the potential interaction between PE and AFB 1 . The greatest inhibitory effect of the PE on AFB 1 mutagenicity occurred when PE and AFB 1 were incubated together. When the bacteria were first incubated with PE followed by a second incubation with AFB 1 , lower inhibition was observed. Lower inhibition was also observed when the bacteria were first incubated with AFB 1 followed by a second incubation with PE. The results suggest that the mechanism of inhibition could involve the formation of a chemical complex between of PE and AFB 1 .     

Effect of aqueous and alkaline thermal treatments on chemical composition and oligosaccharide,alkaloid and tannin contents of Lupinus campestris seeds

The utilisation of Lupinus campestris seeds has been limited for some years owing to the presence of toxic quinolizidine alkaloids (QAs) and antinutritional factors (ANFs). The oligosaccharide content was analysed by high‐pressure liquid chromatography (HPLC). Gas chromatography coupled with mass spectrometry (GC/MS) was used to detect alkaloids, using caffeine (0.2 mg ml ⁻¹) as internal standard. Tannins were determined by the Folin–Dennis colorimetric method. Two methods were tested to reduce or eliminate the QAs and ANFs, (a) aqueous thermal treatment and (b) alkaline thermal treatment (NaHCO₃ 0.5% solution), both of them for 6 h at boiling temperature. In both cases the removal of oligosaccharides, in amounts of 70 and 90% respectively, was also achieved. The alkaloid contents were reduced to innocuous levels in both cases (less than 0.4–0.5%). The alkaline thermal treatment, in which the seed had a final alkaloid content of 0.002%, was more efficient than the aqueous thermal treatment. The tannin content also showed a reduction of 71% with the aqueous treatment and 77% with the alkaline treatment. The results show that alkaline thermal treatment is more efficient at eliminating these ANFs. © 2001 Society of Chemical Industry     

Bacterial removal of quinolizidine alkaloids from Lupinus albus flours

The bacterial detoxification of bitter lupine seed flours using two bacterial strains, previously shown to catabolize lupanine and to degrade other lupine alkaloids in liquid culture media containing protein, is described. The experimental starting conditions were selected to match the compositions and temperatures that might be expected in an industrial operation. A response surface methodology was used to pinpoint trends in alkaloid removal and to determine the best operating conditions for each strain. Alkaloid removal was modeled and the major constraints were identified. Based on the results obtained, it is suggested that enzymatically active bacterial lysates or purified enzyme complexes may possess a high potential for the detoxification of this material, thus constituting a new potential alternative for the processing of lupine seed material into valuable food ingredients.     

Antioxidant activity and phenolic compounds of fractions from Portulaca oleracea L.

Portulaca oleracea fractions obtained from the crude extract of the plant by reversed-phase separation were investigated for their antioxidant activities and phenolic compounds content. Five fractions were classified based on optical absorption between the wavelength range of 200–400 nm. Fraction 3 displayed higher absorption than the other fractions. The total amount of quantified phenolics in this fraction was found to be quite high compared to that of crude extract. Chlorogenic, caffeic, p-coumaric, ferulic and rosmarinic acids were the free phenolic acids, and quercetin and kaempferol were the free flavonoids detected in Fraction 3. IC₅₀ value of crude extract was found to be 511.8 μg/ml whereas Fraction 3 exhibited an IC₅₀ value of 154.1 μg/ml. TEAC of Fraction 3 was found to be almost four times higher than that of the crude extract. Fraction 3 was also found to show the highest lipid peroxidation inhibiting capacity, determined by TBARS assay.     

Aqueous extraction kinetics of phenolic compounds from jamun (Syzygium cumini L.) seeds

In this study, aqueous extraction of phenolic compounds from jamun (Syzygium cumini L.) seed was undertaken. The effects of various parameters such as extraction temperature (34.8–85.2°C), extraction time (49.8–100.2 min), and liquid-to-solid ratio (9.8–60.2 mL/g) on the extraction yield, extract purity (i.e., total polyphenol content), and its antioxidant activities (1,1-diphenyl-2-picrlthydrazyl free radical scavenging assay and ferric reducing antioxidant power) were investigated. Response surface methodology was used to optimize the extraction conditions. The optimum extraction conditions (49.2°C, 89.4 min, and 51.6:1 mL/g) produced an extract with 17.3% extraction yield, high total polyphenol content (415 mg gallic acid equivalent/g dried extract) and significant antioxidant activity (IC₅₀: 35.4 ± 0.7 µg/mL). The high-performance liquid chromatography analysis of seed extract revealed the presence of gallic acid (90.8 mg/g dried extract), ellagic acid (36 mg/g dried extract), caffeic acid (26.07 mg/g dried extract), p-coumaric acid (0.26 mg/g dried extract), catechin (9.05 mg/g dried extract), epicatechin (0.42 mg/g dried extract), and quercetin (1.54 mg/g dried extract). Tannic acid (188.5 mg/g dried extract) was also identified as a major phenolic compound. The extraction kinetics was also studied and experimental data were fitted to four kinetic models such as first-order model, second-order model, Peleg’s model, and Minchev and Minkov model, to evaluate their applicability.     

On the extraction and antioxidant activity of phenolic compounds from winery wastes

Winery waste (from red winemaking, variety Agiorgitiko) was extracted under various conditions using different solvents. The minimum time required for ensuring maximum extraction of phenols was 180 min at a solvent to sample ratio 9:1 v/w and at pH 1.5. The antioxidant activity of solvent extracts was investigated by DPPH radical scavenging method, by determination of peroxide value on virgin olive oil and by the Rancimat method on sunflower oil. Ethanol extract exhibited the highest antioxidant activity compared to the other solvent extracts, to synthetic food antioxidants BHT, ascorbyl palmitate and to the natural food antioxidant, vitamin E. No correlation was found between antioxidant activity and total phenol content. HPLC analysis of the extracts showed that gallic acid, catechin and epicatechin were the major phenolic compounds in winery waste. Hydroxytyrosol, tyrosol, cyanidin glycosides and various phenolic acids such as caffeic, syringic, vanillic, p-coumaric and o-coumaric acids were also identified.     

油茶籽多酚超声辅助提取的响应面优化

采用Plackett-Burman(PB)筛选和中心组合设计(cen-tral composite design,CCD)对影响油茶籽多酚甲醇超声辅助提取过程的5个因素进行筛选及优化,确定最优超声辅助提取条件:提取温度50℃,料液比1∶38(m∶V),超声时间40min,甲醇体积分数60%,pH值为7,该条件下油茶籽多酚提取量可达21.037 7mg/g。     

Antioxidant activity of the phenolic compounds of hawthorn,pine and skullcap

The significance of antioxidants in preventive medicine is well known. Increasing interest has been devoted to naturally occurring compounds – polyphenols – because of their beneficial health effects. The subject of this study was to examine the antioxidative activity of polyphenolic preparations containing oligomeric procyanidin from the bark of common pine (Pinus sylvestris L.) and hawthorn (Crataegus oxyacantha L.) and flavones of skullcap (Scutellaria baicalensis Georgi) roots. Multi-constituent mixtures were fractionated, and the antioxidative activity of fractions was tested in vitro with linoleic acid oxidation by AAPH-generated radicals. All preparations at 6 and 12 ppm concentrations exhibited protective activity, from 45% to 95% in relation to the control sample. The average activity of preparations was higher than those of their fractions used at the same concentrations, and it was similar to trolox and BHT activity.     

Respiratory activity and phenolic compounds in pre-cut celery

The effect of temperature on respiratory activity and total phenol and flavonoid contents in pre-cut celery was assessed within the 24 h following this minimal processing. To this end, celery petioles were cut as strips, conditioned in crystal polyethylene terephthalate trays covered with PVC film and stored at 0, 10 and 20 °C. Samples were removed at 0, 2, 4, 6 and 24 h after processing to analyse respiratory activity and concentrations of total phenols and flavones. For the samples kept at 0 °C for 24 h, chlorogenic acid was also determined, along with total flavonoids and antioxidant power. At this temperature, the total phenol contents remained basically constant, though at 10 °C it increased considerably two hours after applying the cutting stress. At 20 °C the increase observed was less important. The flavones, identified by HPLC in pre-cut celery were apigenin and luteolin, whose concentrations also increased between two to six hours after processing. However, exposure for 24 h at 0 °C produced a considerable decrease in total flavonoids.     

多齿红山茶籽多酚组分的抗氧活性研究

采用半制备高效液相色谱法对多齿红山油茶籽中的多酚类物质进行分离制备,收集分离色谱图中10个主要峰,采用DPPH法和ABTS法测定其抗氧化活性.结果表明:10种馏分的DPPH·自由基清除能力均低于L-抗坏血酸;馏分3对ABTS·+自由基的清除能力强于生育酚,其它9种馏分的清除能力低于生育酚.     

Antioxidant activity of phenolic compounds from canola (Brassica napus) seed

The antioxidant activities of various extracts from canola (Brassica napus) seed were investigated using the DPPH assay, ABTS radical assay, and reducing power. An 80% methanol extract from canola seed was sequentially fractionated and separated according to the solvent polarity and Sephadex LH-20 chromatography, respectively. The antioxidant activities of various extracts and their total phenolic content (TPC) and total flavonoid content (TFC) were closely correlated, resulting in correlation coefficient values higher than 0.87. Of all extracts, the sub-fraction 3 had the highest TPC (462.3 μg/mg) and TFC (75.4 μg/mg) while it showed the lowest EC₅₀ value (183.1 μg/mL). The EC₅₀ value of sub-fraction 3 measured using the DPPH radical assay was 1.3 times lower than that of butylated hydroxytoluene (BHT). The major free phenolic compound was trans-sinapic acid (193.4 μg/mg) and sinapic acid derivatives identified as 1-O-β-d-glucopyranosyl sinapate and 1,2-di-O-sinapoyl-β-d-glucose in sub-fraction 3.     

Primary structure of 2S albumin from seeds of Lupinus albus

 The 2S albumin from the seeds of white lupin (Lupinus albus L.) was purified by ammonium sulfate precipitation and ultrafiltration followed by anion-exchange and reversed-phase HPLC. The complete amino acid sequences of the large and the dominating small subunit were determined by automated Edman degradation of the reduced and S-pyridylethylated polypeptides and of their enzymatic fragments. The small subunit of the 2S albumin (a) consists of 37 amino acid residues resulting in a molecular mass M _r of 4407. The large subunit (b) contains 75 amino acid residues (M _r=8827). The two polypeptide chains are linked by two interchain disulfide bonds (Cys^a8-Cys^b24 and Cys^a20-Cys^b13 or, more probably, Cys^a20-Cys^b12). In addition, the large polypeptide contains two intrachain disulfide bridges (Cys^b26-Cys^b68 and Cys^b12-Cys^b60 or, more probably, Cys^b13-Cys^b60) and one free sulfhydryl group (Cys^b40). A high degree of homology (88%) exists between the primary structure of the 2S albumin from L. albus and that of a comparable 2S protein from L. angustifolius, designated conglutin δ. Received: 4 April 1996