Antioxidant activity of crude tannins of canola and rapeseed hulls

The antioxidant activity of crude tannins of canola and rapeseed hulls was evaluated by β-carotene-linoleate, α,α-diphenyl-β-picrylhydrazyl (DPPH) radical, and reducing power assays. Crude tannins were extracted from three samples of Cyclone canola (high-tannin) hulls and Kolner, Ligaret, and Leo Polish rapeseed (low-tannin) hulls with 70% (vol/vol) acetone. The total phenolic content in crude tannin extracts ranged between 128 and 296 mg of sinapic acid equivalents per 1 g of extract. The ultraviolet spectra of methanolic solution of canola extracts showed two absorption maxima (282 and 309 nm), whereas those of rapeseed extracts exhibited a single maximum (326 nm). Crude tannins isolated from canola hulls exerted significantly (P<0.025) greater antioxidant activity than those from rapeseed in all three assays. The scavenging effect of all crude tannins, at a dose of 1 mg, on the DPPH radical ranged from 35.2 to 50.5%. The reducing power of Cyclone canola hull extracts on potassium ferricyanide was significantly (P≤0.0025) greater than that of rapeseed hull extracts, and the observed data correlated well (r=0.966; P=0.002) with the total content of phenolics present.     

Effect of Operating Parameters on Oil and Phenolic Extraction Using Supercritical CO<Subscript>2</Subscript>

Supercritical fluid extraction (SFE) with carbon dioxide was used to extract oil from canola press cake. Different operating conditions, e.g. pressure, temperature, and co-solvent % were investigated to optimize extraction parameters to yield canola meal with <4% oil. The residual oil content in the extracted canola meal reduced to 2.1–2.9% in our experimental trials. Residues of the optimum conditions based on oil yield were compared for the total phenolic content and the main phenolic compounds. Sinapine (the choline ester of sinapic acid) was the major phenolic constituent in both the SFE and n-hexane extracted canola meals and press cakes. n-Hexane extracted residues showed the retention of the highest sinapic acid, sinapine, sinapoyl glucose and total phenolic contents (mg/g) while the SF-extracted residues showed the lowest values for these compounds.     

A rapid high-performance liquid chromatographic method for the determination of sinapine and sinapic acid in canola seed and meal

A high-performance liquid chromatographic (HPLC) method has been developed to separate sinapine and sinapic acid from other phenolics in canola seed and meal in a single run. The separation was achieved with a reverse-phase C18 column. Owing to the higher recovery of phenolics and ease of use, refluxing with 100% methanol for 20 min was selected as the extraction method for HPLC analysis and determination of total phenolics using Folin-Ciocalteu reagent. A 10-min isocratic/linear/concave gradient and a 15-min isocratic/linear gradient were selected as the best gradients for the separation of these phenolic compounds. Peak identities for sinapine and sinapic acid were verified with ion exchange separation followed by HPLC analysis. The method was calibrated using sinapine bisulfate and sinapic acid standards; correlation coefficients (R ²) for the calibration curves were 0.997 and 0.999 for sinapine bisulfate and sinapic acid, respectively. The extinction coefficient of sinapine was determined to be 1.16 times that of sinapic acid at the detector wavelength (330 nm). Applying this method to routine canola phenolic analyses can greatly reduce the cost by simplifying the procedures and reducing the time required for each determination.     

The Interactions Between Rapeseed Lipoxygenase and Native Polyphenolic Compounds in a Model System

The focus of the present research was to study inhibition of lipoxygenase activity by rapeseed native polyphenols and the interactions between those compounds and the enzyme. The enzyme and polyphenolic compounds (polyphenols, phenolic acids) were extracted from rapeseed (Brassica napus) varieties Aviso and PR45DO3. The total phenolic compounds concentration in tested rapeseed was 1,485–1,691 mg/100 g d.m. (dry matter) and the free phenolic acids content in both rapeseed varieties was about 76 μg/100 g d.m. The isolated proteins showed lipoxygenase activity. Prooxidant properties of phenolic compounds in the presence of lipoxygenase and linoleic acid were observed rather in the case of extracts containing a relatively high concentration of miscellaneous polyphenols. Antioxidant properties were recorded in the case of phenolic acid extracts which contain only 1.4–1.9% of phenolics present in raw phenolic extracts. We propose that the prooxidant effect of phenolic compounds comes from quinone and oxidized polyphenols formation. The observed antioxidant activity of phenolic acid extracts is probably due to their ability to scavenge free radicals formed from linoleic acid. However, reduction of lipoxygenase ferric to ferrous ions, which prevent the activation of the enzyme and inhibited its activity, was also observed.     

Antioxidant activity of rapeseed phenolics and their interactions with tocopherols during lipid oxidation

Commercial rapeseed press cakes are rich sources of phenolic compounds, namely, sinapic acid derivatives, which can be extracted as free sinapic acid and its bound forms (such as sinapine, the choline ester of sinapic acid). Fractionated rapeseed extracts rich in sinapic acid and sinapine were compared for their capacity to inhibit the formation of lipid oxidation products. Oxidation at 40°C was monitored by the formation of hydroperoxides (indicating primary oxidation products) and propanal (secondary oxidation products). The 70% methanolic extract of rapeseed meal, added as an equivalent of 500 μmol/kg oil (based on sinapic acid equivalent for sinapic acid-rich extracts or sinapine equivalent for sinapinerich extracts) showed good antioxidative activity compared with the addition of 500 μmol/kg oil sinapic acid. Apart from this, the interaction between a mixture of α-/γ-tocopherol and sinapic acid was investigated using response surface methodology for the experimental design. The experiments indicated that the addition of sinapic acid (concentration dependent) caused inhibition of peroxide formation, complementing further lower endogenous tocopherol concentration in oils. This paper was initially presented at the 95th AOCS Annual Meeting and Expo in Cincinnati, Ohio, May 1–4, 2004.     

Attenuation of sinapic acid and sinapine-derived flavor-active compounds using a factorial-based pressurized high-temperature processing

De-oiled canola meals are sources of protein-containing flavor-active phenolic compounds. Conventional canola oil processing utilizes an excess amount of solvents and is associated with the release of high-intensity bitter flavor-active phenolic compounds, limiting the use of the canola meal. Recent advances in the extraction and isolation of the bitter favor-active phenolic compounds from canola by-products produce protein isolates, however, would benefit the industry by producing a side-stream ingredient rich in phenolics. High temperature and pressure-aided processing, namely the accelerated solvent extraction (ASE) was investigated to extract the flavor-active bitter molecules from the canola meal. The extractability of flavor-active phenolic compounds including the major sinapates, kaempferol derivatives, and other thermo-generative compounds including thomasidioc acid (TA) was evaluated. The effects of temperature, solvent extractant and concentration, and the particle size of the meal were examined on the extraction efficiency of these phenolic compounds. Extraction temperature (180°C) was the primary determinant (p < 0.05) for the attenuation of major sinapates including sinapine and sinapic acid. Both ethanol and methanol extractants at a concentration of 70% (v/v) significantly (p < 0.05) extracted the flavor-active phenolic compounds. The pressurized high temperature through optimized ASE conditions attenuated the bitter undesirable flavor-active phenolic molecules from canola meal, thereby facilitating a potential value-added phenolic-rich by-product.     

Production of Canolol from Canola Meal Phenolics via Hydrolysis and Microwave-Induced Decarboxylation

A potent antioxidant, anti-inflammatory and anti-mutagenic agent; 4-vinyl-2,6-dimethoxyphenol (canolol) was obtained from canola meal in a significant yield via alkaline (NaOH)/enzymatic (ferulic acid esterase) hydrolysis followed by microwave-assisted decarboxylation. The hydrolysis was carried out either through using canola meal directly as a substrate or by using the 70 % aqueous methanolic extract filtrates. The hydrolyzed extracts underwent RP-HPLC analysis which showed that 81.0 and 94.8 % of the total phenolics were hydrolyzed to sinapic acid after the alkaline hydrolysis of the meal and the methanolic extracts, respectively. The enzymatic hydrolysis showed lower conversion rates (49.5 and 58.3 %). The hydrolyzed extracts were consequently decarboxylated using 8-diazabicyclo[5.4.0]undec-7-ene under microwave irradiation at different conditions. The HPLC profiling of decarboxylated extracts showed that using microwave at 300 W of microwave power for 12 min brought the highest sinapic acid conversion to canolol (58.3 %) yielding 4.2 mg canolol from each gram of canola meal suggesting that the process could be commercially economical.     

Radical scavenging activity of canola hull phenolics

Possible use of canola hulls as a source of natural anti-oxidants was explored. Cyclone canola hulls were extracted with methanol (30 to 80%, vol/vol) and acetone (30 to 80%, vol/vol). The free radical-scavenging activity of phenolic extracts so prepared was evaluated using the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical ion (ABTS^o−), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and chemiluminescence assays. The total content of phenolics in prepared extracts from canola hulls ranged from 15 to 136 mg sinapic acid equivalents per gram of extract. Higher levels of condensed tannins were detected in the acetone extracts than in the corresponding methanolic counterparts. Seventy and 80% (vol/vol) acetone extracts displayed markedly stronger antioxidant activity than any of the other extracts investigated. Statistically significant linear correlations were found between TEAC (Trolox equivalent antioxidant capacity) values (expressed in mM of Trolox equivalents per gram of extract) and total pehnolics, TEAC and total condensed tannins (i.e., determined using the modified vanillin and pronthocyanidin assays), as well as TEAC and protein precipitation activity of phenolic extracts (i.e., measured using the dye-labeled assay). The antioxidant activities of extracts as determined by the ABTS^o− radical ion assay correlated highly with those of the chemiluminescence and DPPH radical assays.     

Primary Metabolites and Polyphenols in Rapeseed (Brassica napus L.) Cultivars in China

Defatted meals of 10 rapeseed (Brassica napus L.) varieties were investigated for their total phenolic, phenolic acid (free, esterified, and insoluble-bound forms), and tannin contents. The antioxidant capacities (AC) of methanol extracts from samples were assessed using the 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH•), Folin–Ciocalteu method and ferric reducing antioxidant power (FRAP), and β-carotene–linoleic acid tests. In the fraction of free phenolic acids, sinapic, caffeic, ferulic, syringic, gallic, and p-coumaric acids were identified. In the fraction of esterified phenolic acids, sinapine, sinapoyl glucoside, and disinapoyl gentiobiose were identified. After basic hydrolysis, sinapic, ferulic, cinnamic, and 4-hydroxybenzoic acids were identified, and sinapic acid (SA) constituted 98.3% to 99.6% of the total esterified phenolic acids. Eleven components (sinapic, protocatechuic, p-coumaric, syringic, vanillic, gallic, caffeic, ferulic, salicylic, cinnamic, and 4-hydroxybenzoic acids) in the fraction of insoluble-bound phenolic acids were identified. The AC of the samples correlated with the total phenolic content. Overall, the total phenolics showed a better correlation with AC than the individual phenolic compounds. Moreover, SA, sinapoyl glucoside, and disinapoyl gentiobiose showed a highly significant and strong positive correlation with the AC of rapeseed meals, and the derivatives of cinnamic acid showed a higher correlation with AC than the derivatives of benzoic acid. The change in the canolol content in rapeseeds under microwave irradiation is discussed. The correlation of the canolol formed with SA and its derivatives is discussed.     

Antibacterial Activity of Essential Oil and Extracts of <Emphasis Type="Italic">Cleistocalyx operculatus</Emphasis> Buds Against the Bacteria of <Emphasis Type="Italic">Xanthomonas</Emphasis> spp.

This study was undertaken to assess the antibacterial efficacy of the essential oil and extracts of Cleistocalyx operculatus buds against plant pathogenic bacteria of Xanthomonas spp. The diameter of inhibition zones of oil (1,000 μg/disc) and extracts (1,500 μg/disc) against the tested bacteria were found in the range of 7–23 mm. The MIC and MBC values of the oil and extracts against the tested Xanthomonas spp. ranged from 31.25–125 to 62.5–250 μg/ml and 125–500 and 250–1,000 μg/ml, respectively. The cell viability study demonstrated a potential detrimental effect of the oil (1,000 μg/ml) and hexane extract (250 μg/ml) on the tested Xanthomonas spp. Also the oil displayed significant antibacterial effects in vivo against Xoo KX019 and Xsp SK12 conducted on greenhouse-grown oriental melon plants (Cucumis melo L. var. makuwa). The results of this study suggest that C. operculatus-derived essential oil and extracts could be used as natural bactericides in the food and agriculture industries.     

Characterization of Terebinth Fruit Oil and Optimization of Acidolysis Reaction with Caprylic and Stearic Acids

Characterization of the fatty acid and triacylglycerol composition of terebinth fruit oil and the synthesis of structured lipids (SL) were performed in this study. Interesterification reaction of terebinth fruits oil (Pistacia terebinthus L.) with caprylic acid (CA) and stearic acid (SA) to produce a SL was performed in n-hexane using immobilized sn-1,3 specific lipase from Mucor miehei. The effect of reaction conditions and relationship among them were analyzed by response surface methodology (RSM) with a four-factors five-level central composite rotatable experimental design. The four major factors chosen were enzyme load (10–30 wt% based on substrates), reaction time (7–18 h), reaction temperature (40–60 °C) and substrate mole ratio (terebinth oil:SA:CA 1:1:1–1:1:3). The best fitting quadratic model was determined by regression and backward elimination. Based on the fitted model, the optimal reaction conditions for the incorporation of CA and SA were found to be temperature 50 °C; time 18 h; enzyme load 30 wt%; substrate ratio 1:1:3. Under these optimum conditions, the incorporation of SA and CA could be obtained as 19 and 14%, respectively.     

Transformation of 3,5-dimethoxy-4-hydroxy cinnamic acid and its derivatives using enzyme from white-rot fungus Trametes versicolor: Enzyme characteristics and its application

Transformation of 3,5-dimethoxy-4-hydroxy cinnamic acid (sinapic acid), sinapaldehyde, sinapine and sinapoyl in the model system containing an enzyme secreted by the fungus Trametes versicolor was investigated. The affinity of this enzyme was highest for sinapic acid followed by sinapaldehyde and sinapine. The optimum temperature and pH for these transformations were 50°C and pH 3·3, 50°C and pH 4·5, 60°C and pH 4·0 for sinapaldehyde, sinapine, and sinapic acid, respectively. The apparent heat of the enzyme-sinapic acid complex formation is −2557·6 J mol⁻¹. Higher concentrations of sinapine and sinapic acid caused enzyme inhibition. When canola meal was treated with this enzyme the phenolics content in this commodity was decreased by 90%.     

Chemical Characterization of the Seed and Antioxidant Activity of Various Parts of <Emphasis Type="Italic">Salvadora persica</Emphasis>

This study investigated the fatty acid, tocopherol, sterol and total phenolic compounds of Salvadora percica seeds as well as the potential antioxidant activity of the leaves, bark and seedcake extracts. Two samples of S. persica seed collected from Kordofan (sandy soil) and Gezira (heavy clay soil) states in Sudan were used. The predominant fatty acids were 14:0, 16:0 and 18:1 representing 45.50, 35.12 and 10.20% for Kordofan and 45.20, 34.49 and 10.66% for Gezira samples. Gamma-tocopherol was the predominant tocopherol in both samples representing 61.3 and 61.7% of the total tocopherols, respectively, followed by α-tocopherol at 21.1 and 20.2%, respectively. Total sterol content was 3399.6 and 3385.3 mg/kg for Kordofan and Gezira samples, respectively. Beta-sitosterol, campesterol, stigmasterol and Δ5-avenasterol were predominant. The content of total phenolic compounds was determined in S. persica bark (SPB), S. persica leaves (SPL), and S. persica seedcake (SPC) extracts of each sample according to the Folin–Ciocalteau method as 111.70, 132.60, and 66.10 mg GAE/g extract for the Kordofan sample. They were found to be 105.90, 129.10 and 62.90 mg GAE/g extract in the Gezira sample, respectively. The two samples were significantly (P < 0.05) different in total phenolic content with SPL as the highest in both samples. The methanolic extracts of SPL, SPB, and SPC in both samples were markedly effective in inhibiting the oxidation of linoleic acid and subsequent bleaching of β-carotene in comparison with the control. But they were less effective than butylated hydroxyanisole.     

Effects of Geographical Origin on the Conjugated Linolenic Acid of <Emphasis Type="Italic">Trichosanthes kirilowii</Emphasis> Maxim Seed Oil

Trichosanthes kirilowii Maxim (T. kirilowii) seeds from four geographical locations (Changxing, Quzhou, Yuexi, Dongzhi) contained 26.15–49.41% oil and 28.68–37.90% protein. The seed oil was distinguished by the conjugated linolenic acids, punicic acid (PA) and α-eleostearic acid (α-ESA). The main fatty acids in T. kirilowii seed oils were ranked in the following order: punicic acid (33.09–39.15%), linolenic acid (33.77–38.66%), oleic acid (15.15–24.88%), palmitic acid (2.36–4.86%). PA was the main isomer of CLNA (33.09–39.15%). No significant differences were found either in PA content or in α-ESA content of T. kirilowii seed from these geographical locations. Little difference was observed in the quantitative composition of the lipid contents of seeds from different geographical locations. The α-tocopherol content of T. kirilowii seed ranged from 6.34 to 31.74 mg/100 g, with the highest levels in Changxing seeds. The present results showed that T. kirilowii seeds were especially rich in PA, and their contents were not influenced by the geographical locations. Variation in some proximate compositions by geographical locations may be caused by ecological conditions, temperature, climate condition, technical and cultural conditions.     

The Fatty Acid Profile and Phenolic Composition of Descurainia sophia Seeds Extracted by Supercritical CO2

Oil and phenolics were extracted from Descurainia sophia (Sophia) seeds by a supercritical CO₂ system. Extractions were conducted in two sequential steps, first using 100 % CO₂ and then adding 10 % ethanol as co‐solvent. The extracts were collected in each step using two separate collectors operating at different pressures. The extraction run was 3 and 4 h for the first period, and 2 h for the second period. The majority of the oil was collected in the first extraction period while phenolic compounds were obtained in the second extraction period. A combined mode of static/dynamic extraction (3 h running and 1 h soaking in CO₂) was also used in the first extraction period, which enhanced the total extraction yield (29.3 ± 0.5 %) and was comparable to the 4 h extraction yield (31.4 ± 0.1 %). The total fatty acid (FA) content of oil in collector 1 (0.94 g) was nearly twice that in collector 2 (0.60 g). The oil contained 14 FAs with α‐linolenic being predominant (48.5 %), with a total 91.1 % unsaturated FAs, a ω3/ω6 ratio of 2.7, and an erucic acid content of 6.2 %. More than 10 phenolic compounds were detected by HPLC in the Sophia seed extracts of which sinapic acid was the dominant compound. Sophia seed extracts showed high levels of antioxidant activity. These results suggest that Sophia seed oil and phenolics have the potential for functional food and pharmaceutical applications.     

Structural changes of sinapic acid during alkali-induced air oxidation and the development of colored substances

Structural changes of sinapic acid were induced by air oxidation in aqueous solutions at pH 7–10 and followed by spectral and high-performance liquid chromatographic (HPLC) analysis. Color properties of the sinapic acid solutions were determined by taking the transmittance spectra, calculating the Commission Internationale de l’Eclairage (CIE) 1931 tristimulus values, and converting to Hunter L a b values. Reaction rate constants for sinapic acid were determined by a kinetic study based on the quantitative results from HPLC analysis. These reactions were first order with respect to sinapic acid and fit the appropriate equation with a coefficient of R ² >0.97. Sinapic acid was converted to thomasidioic acid with reaction rate constants (k) of 8.54×10⁻⁶, 2.51×10⁻⁵, and 4.87×10⁻⁵ s⁻¹ in phosphate-boric acid buffers of pH 7, 8.5, and 10, respectively. Similar reactions in ammonium bicarbonate buffers were more than 10 times faster. With time, thomasidioic acid further converted to 2,6-dimethoxy-p-benzoquinone and 6-hydroxy-5,7-dimethoxy-2-naphthoic acid. Air oxidation of sinapic acid aqueous solutions caused darkening of the color for the system, with the 2,6-dimethoxy-p-benzoquinone as a major color contributor.     

Ozone Reactivity and Free Radical Scavenging Behavior of Phenolic Secondary Metabolites in Lichens Exposed to Chronic Oxidant Air Pollution from Mexico City

Lichen secondary metabolites putatively protect lichens from a variety of environmental stress factors, but it is unknown whether these substances respond to air pollution. To assess such a possibility, the three major phenolics of two epiphytic lichen species with contrasting tolerance to chronic air pollution from Mexico City were studied by combining experimental reactivity data and measured field contents. The antioxidant activity and antiradical power of boninic (BO), 2-O-methylsekikaic (MA), and usnic (US) acids, isolated from the tolerant Ramalina asahinae and salazinic acid (SA), atranorin (AT), and chloroatranorin (CA), from the sensitive Parmotrema stuppeum, were determined in vitro by kinetic experiments with ozone and the free radical diphenyl picryl hidrazyl (DPPH^•), respectively. In addition, the field contents of these phenolics in the lichens, and the potential antioxidant capacity (PAC) they provide, were compared among three forested sites exposed to urban emissions and a similar, relatively clean site. The six phenolics had antioxidant activity and antiradical power according to these trends: CA >> AT > US > SA ≥ BO ≥ MA for O₃; and CA > AT > US > MA > SA = BO for DPPH^•. The three most reactive phenolics are cortical compounds, located in the lichen portion most exposed to the surrounding environment. In contrast, the less reactive SA, BO, and MA are medullary. Such reactivity patterns indicate that some phenolics may provide antioxidative protection at the air–lichen interface. The higher antioxidant power of CA and AT may be due to the reactive hydroxyl groups at positions 2 and 4 of ring A, instead of the less reactive methoxyl at the same positions in both BO and MA. In the field comparisons, total quantified phenolics were significantly higher near Mexico City for both lichens, except for the tolerant R. asahinae at one site. Nevertheless, only the latter species had significantly increased PAC values at all sites near the city. This result is explained by species-dependent changes in individual phenolics. At the polluted sites, R. asahinae had consistently higher contents of its most reactive phenolic, US, with values approximately twice that of the control site. In contrast, P. stuppeum only increased its less reactive SA (26–35%), but this was counteracted by CA and, to a lesser extent, AT degradation. Thus, the substantial increase in US at the polluted sites appears to be associated with the current ecological success of R. asahinae near the city. On the other hand, the inability of P. stuppeum to overcome degradation of its most reactive phenolic (CA) at the same sites seems to partially explain the declining status of this lichen. These results provide evidence for a protective mechanism in lichens against air pollution based on secondary metabolites, which may eventually determine which species survive in forests stressed by oxidative air pollution.     

Characteristics of Oil from Seeds of 4 Mungbean [<Emphasis Type="Italic">Vigna radiata</Emphasis> (L.) Wilczek] Cultivars Grown in Pakistan

Mungbean is a widely consumed legume globally. This study was carried out for detailed characterization of oils from mungbean seeds from four indigenously cultivated varieties, as very little information is available on the oil composition of mungbean seeds and inter-varietal variation in oil composition. The oil content was relatively low (2.1–2.7%). The investigated physiochemical parameters included refractive indices (RI) at 40 °C (1.4673–1.4698), relative density (0.9580–0.9618), iodine value (IV) (111.4 –117.1), saponification value (SV) (173.1–181.7 mg KOH/g) and unsaponifiable matter (UM) (13.8–15.01%). Phospholipids and triglycerides were the dominant lipid fractions followed by monoglycerides. Linoleic acid and oleic acid were the dominant fatty acids (FA). Characterization was also made by TLC. Tocopherol analysis demonstrated highest content of γ-tocopherol among its isomers, while α-tocotrienol was present in highest amount in all studied cultivars, among its isomers. Results from most of the parameters revealed significant (P ≤ 0.05) differences among the cultivars. The findings of the study reveal mungbean [Vigna radiata (L.) wilczek], to be a potentially valuable legume crop with comparable nutritional quality oil among all the cultivars.     

Effect of baicalein and acetone extract of Scutellaria baicalensis on canola oil oxidation

There is an increasing interest in natural antioxidants present in traditional Chinese herbal medicines. The present study examined the antioxidant activity of heane, acetone, and methanol extracts, as well as baicalein purified from the dry roots of Scutellaria baicalensis Georgi (common name: Huangqin), in heated canola oil. Oxygen consumption and decreases in linoleic acid linolenic acid content were monitored in canola oil held at 90–93°C. Among the three extracts, the acetone extract was most effective against oxidation of canola oil, followed by the methanol extract of the dry roots. The antioxidant activity of these three extracts correlated well with their content of baicalein, which provided strong protection to canola oil from oxidation. The antioxidant activity of Huangqin acetone extract was dose-dependent. The acetone extract at 100 ppm or above was even more effective than butylated hydroxytoluene at 200 ppm in protecting canola oil from oxidation. The present results suggest that the acetone extract of these roots should be further explored as a potential source of natural antioxidants for use in the processed foods.     

Investigating Some Physicochemical Properties and Fatty Acid Composition of Native Black Mulberry (<Emphasis Type="Italic">Morus nigra</Emphasis> L.) Seed Oil

The physicochemical properties of seed and seed oil obtained from the native black mulberry (Morus nigra L.) were investigated in 2008 and 2009. The results showed that the seed consisted of 27.5–33% crude oil, 20.2–22.5% crude protein, 3.5–6% ash, 42.4–46.6% carbohydrate and 112.2–152.0 mg total phenolics/100 g. Twenty different fatty acids were determined, with the percentages varying from 0.02% myristic acid (C14:0) to 78.7% linoleic acid (C18:2). According to the GC analysis of fatty acid methyl esters, linoleic acid (C18:2), followed by palmitic acid (C16:0), oleic acid (C18:1) and stearic acid (C18:0) were the major fatty acids, which together comprised approximately 97% of the total identified fatty acids. High C18:2 content (average 73.7%) proved that the black mulberry seed oil is a good source of the essential fatty acid, linoleic acid. Linolenic acid (C18:3) was also found in a relatively lower amount (0.3–0.5%). The α-tocopherol content was found to be between 0.17 and 0.20 mg in 100 g seed oil. The main sterols in the mulberry seed oil were β-sitosterol, Δ5-avenasterol, Δ5, 23-stigmastadienol, clerosterol, sitosterol and Δ5, 24-stigmastadienol. The present study stated that the native black mulberry seed oil can be used as a nutritional dietary substance and has great usage potential.