Evaluation and characterisation of Citrullus colocynthis (L.) Schrad seed oil: Comparison with Helianthus annuus (sunflower) seed oil

The physicochemical properties, fatty acid, tocopherol, thermal properties, ¹H NMR, FTIR and profiles of non-conventional oil extracted from Citrullus colocynthis (L.) Schrad seeds were evaluated and compared with conventional sunflower seed oil. In addition, the antioxidant properties of C. colocynthis seed oil were also evaluated. The oil content of the C. colocynthis seeds was 23.16%. The main fatty acids in the oil were linoleic acid (66.73%) followed by oleic acid (14.78%), palmitic acid (9.74%), and stearic acid (7.37%). The tocopherol content was 121.85 mg/100 g with γ-tocopherol as the major one (95.49%). The thermogravimetric analysis showed that the oil was thermally stable up to 286.57 °C, and then began to decompose in four stages namely at 377.4 °C, 408.4 °C, 434.9 °C and 559.2 °C. The present study showed that this non-conventional C. colocynthis seed oil can be used for food and non-food applications to supplement or replace some of the conventional oils.     

Sterol content in sunflower seeds (Helianthus annuus L.) as affected by genotypes and environmental conditions

Phytosterols play essential roles in many plant cell mechanisms. They are of industrial interest since, as part of the diet, they can reduce low density lipoprotein cholesterol. An increase in plant sterol contents, by improved crop varieties or crop management, could help to answer industrial demands and also to develop environmentally friendly extraction methods. The aim of this study was to evaluate genotypic variability of sterol content in cultivated sunflower and, in particular, effects of sowing date. Results showed large variability among a collection of sixteen sunflower inbred lines and hybrids. Total sterols varied almost twofold between extreme genotypes. A delay of sowing, giving higher temperatures during seed formation, induced a general increase in total sterol concentration by up to 35%, as well as variation in sterol composition according to genotype. These results are considered with an aim of improving sterol content by sunflower breeding programmes.     

Free radical scavenging activities and bioactive substances of Jerusalem artichoke (Helianthus tuberosus L.) leaves

The total phenolic content and radical scavenging activities of Jerusalem artichoke (Helianthus tuberosus L.) leaves were investigated. Results indicated that the ethyl acetate fraction contained the highest total phenolic content (266.69 ± 2.51 mg GAE/g dry extract) accompanied with strongest free radical scavenging abilities. Following an in vitro radical scavenging activity-guide fractionation procedure, six phenolic compounds which strongly quenched free radicals were separated from ethyl acetate fraction. Among them, 3-O-caffeoylquinic acid and 1,5-dicaffeoylquinic acid played a dominant role due to their strong free radical scavenging abilities and their high contents. The content of 3-O-caffeoylquinic acid in n-butanol fraction was 74.58 ± 1.05 mg/g, while 1,5-dicaffeoylquinic acid in ethyl acetate fraction was 104.51 ± 2.86 mg/g. The results imply that the leaves of Jerusalem artichoke might be a potential source of natural antioxidants.     

Enzymatic browning and after-cooking darkening of Jerusalem artichoke tubers (Helianthus tuberosus L.)

Jerusalem artichoke tubers (Helianthus tuberosus L.) undergo enzymatic browning when peeled or cut, and turn grey after boiling, due to after-cooking darkening reactions between iron and phenolic acids. In an attempt to reveal the components responsible for these discolouration reactions, sensory evaluation and instrumental colour measurements were related to contents of total phenolics, phenolic acids, organic acids and iron in three varieties of raw and boiled Jerusalem artichoke tubers harvested in the autumn and the spring. No differences were found between varieties in sensory evaluated enzymatic browning, but Rema and Draga had higher scores than Mari in after-cooking darkening. Jerusalem artichoke tubers had higher contents of total phenolics, phenolic acids and citric acid in the autumn and low contents in the spring, while it was the opposite for malic acid. None of the chemical parameters investigated could explain the discolouration of the Jerusalem artichoke tubers.     

The in vitro and in vivo antioxidant properties of seabuckthorn (Hippophae rhamnoides L.) seed oil

The antioxidant capacity of seabuckthorn (Hippophae rhamnoides L.) seed oil was investigated with a number of established in vitro assays and in an in vivo study of carbon tetrachloride (CCl₄)-induced oxidative stress in mice. The results showed that DPPH radical scavenging activity, ferrous ion chelating activity, reducing power and inhibition of lipid peroxidation activity all increased with increasing concentrations of seabuckthorn seed oil. Moreover, the EC₅₀ values of seabuckthorn seed oil from the hydrogen peroxide, superoxide radical, hydroxyl radical scavenging assays were 2.63, 2.16 and 0.77 mg/ml, respectively. In the in vivo study, seabuckthorn seed oil inhibited the toxicity of CCl₄, as seen from the significantly increased activities of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. The GSH content in the liver was also increased, whereas hepatic malondialdehyde was reduced. Taken together, these results clearly indicate that seabuckthorn seed oil has significant potential as a natural antioxidant agent.     

Identification and quantification of phenolic compounds from sunflower (Helianthus annuus L.) kernels and shells by HPLC-DAD/ESI-MS

Phenolic compounds were extracted from defatted sunflower (Helianthus annuus L.) kernels and shells and characterised by HPLC with diode array and electrospray ionisation (ESI) mass spectrometric detection in the negative mode. Quantification of individual compounds was carried out by external calibration. Among the eleven compounds analysed 5-O-caffeoylquinic acid was predominant amounting up to 59.1 mg/100 g in the shells and 3050.5 mg/100 g in the kernels. The specific fragmentation patterns of mono- and dihydroxycinnamoylquinic acids allowed the unambiguous distinction of several stereoisomers which have not been described for sunflower seeds and seed shells so far. The total phenolic content of about 4200 mg/100 g on a dry matter basis revealed defatted sunflower meal to be a promising source of phenolic compounds that might be recovered and used as natural antioxidants. Furthermore, the press residues originating from sunflower oil extraction were shown to be still rich in phenolic antioxidants, thus, providing the opportunity to valorize these by-products in terms of sustainable agricultural production.     

Abelmoschus esculentus (L.) Moench. and Abelmoschus moschatus Medik: Seeds production and analysis of the volatile compounds

Nine accessions of Abelmoschus esculentus (L.) Moench. and three of Abelmoschus moschatus Medik were both grown in Central Italy for the evaluation of the production of seeds. Furthermore, the volatiles emitted by the mature seeds were sampled by mean of SPME. Seventy compounds were detected in the headspace of the seeds of A. esculentus. The principal constituents common to all the nine accessions were isopentyl 2-methyl butanoate (24.5–59.1%) and heptanoic acid 2-methylbutyl ester (6.6–13.5%). In the headspace around the seeds of A. moschatus 93 components were detected. Among the main volatiles shared by the three accessions, n-tridecane (1.5–26.9%), isopentyl 2-methyl butanoate (0.2–14.3%) and decanal (1.6–5.7%) should be mentioned. Many differences were present in the volatiles emitted by the various accessions and between the two Abelmoschus species.     

Antioxidative effects of daikon sprout (Raphanus sativus L.) and ginger (Zingiber officinale Roscoe) in rats

The antioxidative effects of vegetables are expected to prevent carcinogenesis. The intake of daikon sprout (Japanese name “kaiware-daikon”, Raphanus sativus L.) or ginger (Zingiber officinale Roscoe) significantly decreased the concentration of urinary thiobarbituric acid-reactive substances (TBARS) in rats as compared with those before the intake. Moreover, the intake of these vegetables reduced urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels in lipopolysaccharide (LPS)-treated rats as compared with those fed a basal diet only. These results show that these vegetables suppress lipid peroxidation and the formation of malonaldehyde, and protect DNA from LPS-induced oxidative damage in rats. The suppression of lipid peroxidation and oxidative DNA damage in rats by the intake of daikon sprout or ginger indicates that these vegetables have an antioxidative effect in vivo which could be related to the prevention of carcinogenesis.     

The dynamics of tocopherol and the effect of high temperature in developing sunflower (Helianthus annuus L.) embryo

To improve sunflower (Helianthus annuus L.) oil quality, the pattern of tocopherol and the effect of brief interval of high temperature on tocopherol accumulation during embryo development were investigated. Total tocopherol content increased linearly from 12 to 33 days after anthesis (DAA) and then remained stable until maturity. γ-Tocopherol content reached a maximum on 33 DAA and then decreased. δ-Tocopherol was not detected until 19 DAA. The effect of brief interval of high temperature (?35 °C for seven consecutive days) on tocopherol accumulation was studied. The accelerating effect of high temperature on tocopherol accumulation on a dry weight basis was detected, but the reduction of tocopherol yield occurred from 12 to 19 DAA because the embryo dry weight was reduced significantly. However, the embryos exposed to a temperature of 35 °C from 12 to 19 DAA significantly increased the tocopherol yield per embryo, with no effect on the dry matter weight. These results are useful for evaluating the tocopherol content in sunflower oil and may help recognizing high quality of the oil.     

Characterisation of fatty acids and bioactive compounds of kachnar (Bauhinia purpurea L.) seed oil

Information concerning the exact composition of kachnar (Bauhinia purpurea) seed oil is scare. In the present contribution, a combination of CC, GC, TLC and normal-phase HPLC were performed to analyse lipid classes, fatty acids and fat-soluble bioactives of kachnar seed oil. n-Hexane extract of kachnar oilseeds was found to be 17.5%. The amount of neutral lipids in the crude seed oil was the highest (ca. 99% of total lipids), followed by glycolipids and phospholipids, respectively. Linoleic, followed by palmitic, oleic and stearic, were the major fatty acids in the crude seed oil and its lipid classes. The ratio of unsaturated fatty acids to saturated fatty acid, was higher in neutral lipid classes than in the polar lipid fractions. The oil was characterised by a relatively high amount of phytosterols, wherein the sterol markers were β-sitosterol and stigmasterol. β-Tocopherol was the major tocopherol isomer with the rest being δ-tocopherol. In consideration of potential utilisation, detailed knowledge of the composition of kachnar (B. purpurea) seed oil is of major importance.     

Volatile compounds from pitanga fruit (Eugenia uniflora L.)

Extracts from pitanga leaves are considered to be effective against many diseases, and are therefore used in popular Brazilian medicines. In this study, the volatile constituents of pitanga fruits (Eugenia uniflora L.) were trapped on to Porapak-Q and eluted with ethyl acetate, and the chemical composition of the extract was analyzed by gas chromatography and gas chromatography/mass spectrometry. Fifty-four compounds were detected, and twenty-nine of those were identified by close matches with standard MS spectra. Monoterpenes (75.3% in mass) were found to comprise the largest class of the pitanga fruit volatiles, including trans-β-ocimene (36.2%), cis-ocimene (13.4%), the isomeric β-ocimene (15.4%) and β-pinene (10.3%). Several known therapeutic constituents of pitanga leaf extract, such as selina-1,3,7(11)-trien-8-one (the major constituent) were also found to be present in the fruit volatile extract, suggesting that the fruit may display therapeutic properties similar to those of the leaf extract.     

Isolation and chemical evaluation of carob (Ceratonia siliqua L.) seed germ

The present investigation was undertaken in order to study the influence of the dehusking procedure on the germ meal composition of carob (Ceratonia siliqua L.) seeds and also to investigate its detailed composition and nutritive value. Meals of carob seed germ were obtained by acid treatment or boiling water treatment of the whole seeds. These procedures allowed to separation of the tight-fitting brown coat of the seed and the removal of the endosperm. Results indicated that the carob germ meal composition could be affected by the isolation procedures. Small reductions were observed in protein and lipid contents in germ meals from acid extraction. The analysis of the carob germ meal (containing fine fragments of husk and endosperm), which could be really obtained industrially, showed the following composition: moisture 8.3%, ash 6.5%, lipids (neutral and polar) 6.6% containing ∼21% of polar lipids, crude proteins 54.7% and energy value 17.5 kJ/g.     

Fat and fatty acids of white lupin (Lupinus albus L.) in comparison to sesame (Sesamum indicum L.)

The study was undertaken to compare fat and fatty acid profiles in white lupin (Lupinus albus ssp. albus) and sesame (Sesamum indicum L.), representing two different families, Fabaceae and Pedaliaceae. Fat levels were 10.74% and 55.44% in seeds of white lupin and sesame, respectively. The results indicated that oleic, linolenic and arachidic acids in seed fat were higher in white lupin than in sesame cultivars. Oleic acid was the predominant fatty acid in white lupin, whereas linoleic acid was predominant in sesame. Fat content (%) was statistically significantly correlated with linoleic, linolenic and arachidic acids at the genotypic level. The fatty acid composition of white lupin is useful for human consumption. Although oil content of white lupin was lower than that of sesame, white sweet lupin could be improved.     

Studies on seed characteristics and chemical composition of three morphotypes of Mucuna urens (L.) Medikus – Fabaceae

Seed characteristics and nutrient composition of three morphotypes of big-grained Mucuna urens (L.) Medikus were studied. Results showed that 100-seed weight ranged from 3200.2 to 4700.9 g, cotyledon weight per seed (23.2–26.6 g) and testa weight per seed (9.0–21.2 g). The testa constituted 43.7%, 28.1% and 44.7% of the average seed weight for morphotypes 1, 2 and 3, respectively. The cotyledon also constituted 56.3%, 71.9% and 55.3% of the average seed weight for morphotypes 1, 2 and 3, respectively. Nutrient composition analyses showed that the three morphotypes of M. urens are good sources of crude protein (19.97–20.57 g 100 g⁻¹), carbohydrate (72.39–75.49 g 100 g⁻¹) and fat (1.84–5.05 g 100 g⁻¹). Other nutritional components, including ascorbic acid, calcium and phosphorus are present in the three morphotypes in moderate amounts. The iron content of the M. urens is low. The three morphotypes contain appreciable amounts of essential amino acid. The oxalate content is low. The variations observed in the seed characteristics and nutrient compositions are suspected to be due to genotype. Genetic improvement of this plant is recommended to remove the itching hair trait so as to encourage its cultivation.     

Antioxidant activity in different parts of roselle (Hibiscus sabdariffa L.) extracts and potential exploitation of the seeds

The calyx of the roselle plant has long been recognised as a source of antioxidants. The objective of this study was to evaluate antioxidant activity, free radical-scavenging and total phenolic content in other parts of the roselle plant. Roselle seed extracts were found to have the highest antioxidant activity and strongest radical-scavenging activity of all plants tested. Methanol extracts showed a positive correlation between phenolic content and antioxidant activity, as measured by β-carotene bleaching assay and DPPH radical-scavenging activity. The antioxidant efficacy of roselle seeds in a whole food system was investigated by testing the effect on lipid oxidation in cooked beef patties stored at 4 °C for 14 days. Results showed that patties treated with roselle seeds had reduced lipid oxidation compared to patties treated with BHT. This study suggests that roselle seeds have the potential to be used as food antioxidants.     

Nutritional properties of yellow mombin (Spondias mombin L.) pulp

Yellow mombin (Spondias mombin L.) is a tropical fruit with increasing acceptance in both national and international fruit markets. The aim of this work was to evaluate the centesimal composition, mineral content, total phenolics, antioxidant activity, and characterize the carotenoids of frozen yellow mombin pulp. Results indicated that the yellow mombin pulp contained an important amount of potassium and copper. The antioxidant activity and total phenolic values scored 17.5 mmol TEAC g⁻¹ and 260 mg galic acid/100 g respectively, higher than those reported for other fruits. Five carotenoids were identified, ??-cryptoxanthin, lutein, zeinoxanthin, ?? and ?? carotene, being ??-cryptoxanthin the major one, accounting for the high level of pro-vitamin A activity in the pulp. A 100 g portion of yellow mombin pulp can provide more than 37% of the recommended daily allowance of vitamin A.     

Chemical and antioxidative assessment of dietary turnip (Brassica rapa var. rapa L.)

The phenolic compounds and organic acids of turnip (Brassica rapa var. rapa L.) edible parts (leaves and stems, flower buds and roots) were determined by HPLC–DAD and HPLC–UV, respectively. The results revealed a profile composed of 14 phenolics (3-p-coumaroylquinic, caffeic, ferulic and sinapic acids, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-sophoroside-7-O-sophoroside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, kaempferol 3,7-O-diglucoside, isorhamnetin 3,7-O-diglucoside, kaempferol 3-O-sophoroside, 1,2-disinapoylgentiobiose, 1,2′-disinapoyl-2-feruloylgentiobiose, kaempferol 3-O-glucoside and isorhamnetin 3-O-glucoside) and six organic acids (aconitic, citric, ketoglutaric, malic, shikimic and fumaric acids). The quantification of the identified compounds showed kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, isorhamnetin 3,7-O-diglucoside and isorhamnetin 3-O-glucoside as the main phenolics, and malic acid as the organic acid present in highest amounts. A screening of the antioxidative potential was also performed by means of the DPPH radical scavenging assay. Turnip flower buds exhibited the strongest antioxidant capacity.     

Anthocyanins and polyphenol oxidase from dried arils of pomegranate (Punica granatum L.)

Anthocyanins are natural pigments responsible for red, purple, and blue colouration in plants. Human consumption of anthocyanins is increasing because of the rising awareness and interest in their potential health benefits. Pomegranate is one of the major sources of polyphenolic phytochemicals, such as anthocyanins. Dried pomegranate raisins (anardana) are consumed in large quantities in Asian countries, and contain substantial amounts of anthocyanins. Five anthocyanins were found to be present in pomegranate raisins. Drying adversely affected the amount of anthocyanins, with polyphenol oxidase (PPO) playing a possible role in oxidative degradation of anthocyanins. Anthocyanins are heat-stable compounds, and inactivation of PPO by processing at high temperature for short periods may prevent PPO-catalysed anthocyanin oxidation in pomegranate arils. Pomegranate PPO kinetics were partially characterised by investigating the effect of substrate (catechol) concentration; optimum pH for PPO activity was found to be 6.0.     

Nutrient composition of hazelnut (Corylus avellana L.) varieties cultivated in Turkey

In this study, chemical composition of the 17 different hazelnut varieties grown in the Black Sea Region of Turkey was investigated. The main fatty acids in hazelnut varieties were oleic (79.4%), linoleic (13.0%) and palmitic acid (5.4%). The ratios of polyunsaturated/saturated and unsaturated/saturated fatty acids of hazelnuts varieties were found to be between 1.23 and 2.87, and 11.1 and 16.4, respectively. The average niacin, vitamin B₁, vitamin B₂, vitamin B₆, ascorbic acid, folic acid, retinol and total tocopherol contents of hazelnut kernels were 1.45 mg/100 g, 0.28 mg/100 g, 0.05 mg/100 g, 0.5 mg/100 g, 2.45 mg/100 g, 0.043 mg/100 g, 3.25 mg/100 g and 26.9 mg/100 g, respectively. The amount of the essential amino acids, mostly as arginine (2003 mg/100 g) and leucine (1150 mg/100 g), and the non-essential amino acids, mostly as glutamic acid (2714 mg/100 g) and aspartic acid (1493 mg/100 g) were also determined in the hazelnut varieties. Mineral compositions of the hazelnut varieties, e.g., K, Mn, Mg, Ca, Fe, Zn, Na and Cu were (averagely) measured as 863 mg/100 g, 186 mg/100 g, 173 mg/100 g, 5.6 mg/100 g, 4.2 mg/100 g, 2.9 mg/100 g, 2.6 mg/100 g and 2.3 mg/100 g, respectively.