Araçá (Psidium cattleianum Sabine) fruit extracts with antioxidant and antimicrobial activities and antiproliferative effect on human cancer cells

Araçá or strawberry guava (Psidium cattleianum Sabine) is an attractive tasty small fruit native to temperate zones of Brazil. In this study, functional chemical constituents and the nutraceutical and therapeutic potential of aqueous and acetone extracts of red and yellow accessions of araçá were characterised. While carotenes, ascorbic acid, and anthocyanins were present as minor constituents, araçá fruit presented high levels of phenolic compounds (up to 768 mg 100 g⁻¹ fresh fruit pulp, ffp), particularly (−)-epicatechin (up to 2.7 mg g⁻¹ ffp), which were in general more efficiently extracted with acetone. Abundance of phenolic compounds was positively correlated with antioxidant activity, antimicrobial and antiproliferative effects.     

An industrial approach in the search of natural antioxidants from vegetable and fruit wastes

Eleven fruit and vegetable byproducts and two minor crops were screened for industrial polyphenol exploitation potential by determination of their extraction yield, total phenolic content (TPC, Folin–Ciocalteu), and antioxidant activity (NTZ/hypoxanthine superoxide assay, ferric thiocyanate method). Extracts with the highest activity, economic justification and phenolic content were obtained from apple (TPC maximum 48.6 ± 0.9 mg Gallic acid equivalents g⁻¹ dry extract), pear (60.7 ± 0.9 mg GAE g⁻¹), tomato (61.0 ± 3.0 mg GAE g⁻¹), golden rod (251.4 ± 7.0 mg GAE g⁻¹) and artichoke (514.2 ± 14.9 mg GAE g⁻¹). Apple, golden rod and artichoke byproducts were extracted at pilot plant scale and their antioxidant activity was confirmed by determination of their free radical scavenging activity (DPPH) and the inhibition of stimulated linoleic acid peroxidation (TBA and Rancimat^® methods). The preservative effect of the three extracts (determination of the peroxide value in test crème formulations with 0.1–1.0% extract concentrations) was similar to the established antioxidants Oxynex^® 0.1%, Controx^® KS 0.15%, and butylated hydroxytoluene (BHT) 0.01%. This study demonstrates the possibility of recovering high amounts of phenolics with antioxidant properties from fruit and vegetable residuals not only for food but also cosmetic applications.     

Nutrient contents of kale (Brassica oleraceae L. var. acephala DC.)

Fructose, glucose and sucrose, as the major soluble sugars and citric and malic acids, as the major organic acids, were identified and determined in kale (Brassica oleraceae L. var. acephala DC., black cabbage) leaves. Fructose was the predominant sugar (2011 mg 100 g⁻¹ dry wt) identified, followed by glucose (1056 mg 100 g⁻¹ dry wt) and sucrose (894 mg 100 g⁻¹ dry wt). The contents of citric and malic acids were at 2213 and 151 mg 100 g⁻¹ dry wt in the leaves. The 16:0, 18:2n − 6 and 18:3n − 3 fatty acids were the most abundant fatty acids in the leaves. Considering the level of these fatty acids, 18:3n − 3 was found to be the highest (85.3 μg g⁻¹ dry wt), contributing 54.0% of the total fatty acid content. Linoleic acid (18:2n − 6), being the second most abundant fatty acid was present at 18.6 μg g⁻¹ dry wt, contributing 11.8% of the total fatty acid content. In the seed oil of kale, 22:1n − 9 was the most abundant fatty acid (4198 μg g⁻¹ dry wt, 45.7%), with 18:2n − 6 (1199 μg g⁻¹ dry wt, 12.3%) and 18:1n − 9 (1408 μg g⁻¹ dry wt, 14.8%) being the second next most abundant fatty acids. The most abundant amino acid was glutamic acid (Glu) which was present at 33.2 mg g⁻¹ dry wt. Aspartic acid, which was the second most abundant amino acid, was present at 27.6 mg g⁻¹ dry wt and accounted for 10.2% of the total amino acid content of kale leaf. The amino acid content was assessed by comparing the percentages of the essential amino acids in kale leaf versus those of a World Health Organization (WHO) standard protein. The protein of kale leaf compares well with that of the WHO standard. Only one amino acid, lysine, had a score that fell below 100%; the lysine score of kale leaf was 95%. This study attempts to contribute to knowledge of the nutritional properties of the plant. These results may be useful for the evaluation of dietary information.     

Chemical composition and antioxidant activity of Gaylussacia brasiliensis (camarinha) grown in Brazil

This paper presents the centesimal and mineral composition, fatty acid profile of the lipidic fraction, phenolic and anthocyanin contents, and antioxidant activity of Gaylussacia brasiliensis fruit. The results indicated the following composition: moisture (81.30%), lipids (0.62%), proteins (0.56%), carbohydrates (10.74%), dietary fiber (6.53%), and ash (0.25%). The main elements comprising the mineral composition were K, Mg, Ca, and Fe. The fatty acid composition was characterized by a high content of polyunsaturated fatty acids (62.2%) and a high PUFA/SFA ratio (2.92). The G. brasiliensis fruit contained considerable amounts of phenolics (492.87 mgAG/100 g) and anthocyanins (240.43 mg/100 g), which contribute to its high antioxidant activity. This study highlights the potential of this fruit as an important source of both nutritional and bioactive compounds available in the native Brazilian flora.     

Preliminary evaluation of nutraceutical and therapeutic potential of raw Spondias pinnata K., an exotic fruit of India

The underutilized, edible green raw (whole) fruits of amra, Spondias pinnata K. (Anacardiaceae family) from the eastern region of India were investigated for their nutraceutical and therapeutic potential. A thorough nutritional characterization of this fruit demonstrated it as a source of energy (348 kcal/100 g DM), phenolic compounds, natural antioxidants and minerals. It is also a moderate source of ascorbic acid, malic acid, calcium, phosphorus and other nutrients. The phytochemical screening revealed 5.12 ± 0.32 mg 100 g^− 1 DM of alkaloids followed by saponins and tannins. All assays were carried out in three different solvent extracts of the fruit. Total phenolic, flavonoid and flavonol contents were obtained as 210 ± 1.89 mg GAE, 28.0 ± 0.91 mg CE and 9.97 ± 0.72 mg RE respectively in 100 mg mix solvent extract (MSE). Antioxidant activity of different extracts (as DPPH scavenging) ranged from 0.73 to 0.59 mg ml^− 1 as IC₅₀ value, ABTS with a trolox equivalent antioxidant concentration (TEAC) value as 0.68 to 0.83 and FRAP 5.97 to 7.93 mg TE 100 mg^− 1 extract. LC- MS/MS analysis revealed the presence of gallic acid, salicylic acid, chlorogenic acid, ellagic acid, p-coumaric acid, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, quercetin, catechin, myrecetin and rutin. The MSE showed the highest antimicrobial activity (against Listeria monocytogenes (MIC 1.8 mg ml^− 1)) and ??-amylase inhibition capacity (as IC₅₀: 29.3 mg ml^− 1 extract). GC/MS screening showed the presence of vitamin E, furfural, phytosterol, campesterol and fatty acids. Analysis of volatile flavor showed isopropyl myristinate as a major compound followed by the other monoterpenes and sesquiterpenes. The current study explains the nutritional as well as medicinal utility of the fruit which is a rich source of minerals and antioxidants such as phenols and flavonoids.     

Antioxidant capacity and phenolic compounds in commercially grown native Australian herbs and spices

The antioxidant capacities and phenolic composition in six native, commercially grown, Australian herbs and spices were investigated. Tasmannia pepper leaf, followed by anise myrtle and lemon myrtle contained the highest levels of total phenolics (TP; 102.1; 55.9 and 31.4 mg gallic acid equivalents (GAE)/g dry weight (DW), respectively). Tasmannia pepper leaf exhibited the highest oxygen radical absorbance capacity (ORAC assay) followed by lemon myrtle and anise myrtle. Anise myrtle exhibited the highest total reducing capacity [TRC; Ferric Reducing Antioxidant Power (FRAP) assay], followed by Tasmannia pepper leaf and lemon myrtle. Australian bush tomato, with TP content of 12.4 ± 0.9 mg GAE/gDW and TRC of 206.2 μMol Fe⁺²/gDW, resembled the Chinese Barbary Wolfberry fruit. The TP content of Tasmannia pepper berry (16.86 mg GAE/gDW) was similar to that of black pepper, but it’s TRC was 25% lower. Cinnamic acids and flavonoids, tentatively identified by mass spectrometry, were identified as the main sources of antioxidant activities.     

European elderberry (Sambucus nigra L.) rich in sugars,organic acids,anthocyanins and selected polyphenols

Sugars and organic acids in the fruit of two cultivars and three selections of black elderberry (Sambucus nigra L.): ‘Haschberg’, ‘Rubini’, ‘Selection 13’, ‘Selection 14’ and ‘Selection 25’ were quantified. The anthocyanin as well as quercetin profiles of this plant material were also established by the use of HPLC/MS. Significant differences in the concentration of sugars and organic acids were detected between the widely spread cultivar ‘Haschberg’ and all other cultivars/selections; ‘Haschberg’ was the richest in organic acids (6.38 g kg⁻¹ FW), and it contained the least sugar (68.5 g kg⁻¹ FW). The following major cyanidin based anthocyanins were identified in the fruit of black elderberry: cyanidin 3-sambubioside-5-glucoside, cyanidin 3,5-diglucoside, cyanidin 3-sambubioside, cyanidin 3-glucoside and cyanidin 3-rutinoside. The most abundant anthocyanin in elderberry fruit was cyanidin 3-sambubioside, which accounted for more than half of all anthocyanins identified in the berries. The ‘Rubini’ cultivar had the highest amount of the anthocyanins identified (1265 mg/100 g FW) and the lowest amount was measured in berries of the ‘Selection 14’ (603 mg/100 g FW). The ‘Haschberg’ cultivar contained a relatively low amount of anthocyanins in ripe berries (737 mg/100 g FW). From the quercetin group, quercetin, quercetin 3-rutinoside and quercetin 3-glucoside were identified; the latter prevailing in black elderberry fruit. The cultivar with the highest amount of total quercetins was ‘Selection 25’ (73.4 mg/100 g FW), while the ‘Haschberg’ cultivar contained average amounts of quercetins (61.3 mg/100 g FW). The chemical composition of the ‘Haschberg’ cultivar, the most commonly planted, conforms to the standards for sugars, anthocyanins and quercetins and exceeds them in the content levels of organic acids, the most important parameter in fruit processing.     

Phytochemical composition and thermal stability of two commercial açai species, Euterpe oleracea and Euterpe precatoria

Açai fruit are native to the Amazon region of South America and two predominant species are commercially exported as fruit pulps for use in food and beverage applications. Detailed characterisation of the polyphenolic compounds present in the de-seeded fruits of Euterpe oleracea and Euterpe precatoria species were conducted by HPLC–ESI–MSⁿ analyses and their thermal stability and overall influence on antioxidant capacity were determined. Anthocyanins were the predominant polyphenolics in both E. oleracea (2247 ± 23 mg/kg) and E. precatoria (3,458 ± 16 mg/kg) species, and accounted for nearly 90% of the trolox equivalent antioxidant capacity in both E. oleracea (87.4 ± 4.4 μmol TE/g) and E. precatoria (114 ± 6.9 μmol TE/g) fruits. Various flavones, including homoorientin, orientin, taxifolin deoxyhexose and isovitexin; various flavanol derivatives, including (+)-catechin, (−)-epicatechin, procyanidin dimers and trimers, and phenolic acids, including protocatechuic, p-hydroxybenzoic, vanillic, syringic and ferulic acids, were also present in both species. Thermal stability of these compounds was evaluated, following a thermal holding cycle (80 °C for up to 60 min) in the presence and absence of oxygen. Both species experienced only minor changes (<5%) in non-anthocyanin polyphenolic contents during all thermal processes whereas 34 ± 2.3% of anthocyanins in E. oleracea and 10.3 ± 1.1% of anthocyanins in E. precatoria were lost under these conditions, regardless of the presence of oxygen. Proportional decreases (10–25%) in antioxidant capacity accompanied the anthocyanin changes. Results suggest that both açai species are characterised by similar polyphenolic profiles, comparable antioxidant capacities, yet only moderate phytochemical stability during heating.     

Comparison of free amino acid,carbohydrates concentrations in Korean edible and medicinal mushrooms

Ten popular species of both edible and medicinal Korean mushrooms were analysed for their free amino acids and disaccharides. The average total free amino acid concentration was 120.79 mg g⁻¹ in edible mushrooms and 61.47 mg g⁻¹ in medicinal mushrooms, respectively. The average total of free amino acids for all mushrooms, edible mushrooms and medicinal mushrooms was 91.13 mg g⁻¹. Agaricus blazei (227.00 mg g⁻¹) showed the highest concentration of total free amino acids; on the other hand, Inonotus obliquus (2.00 mg g⁻¹) showed the lowest concentration among the 10 species of mushrooms. The average total carbohydrates concentration was 46.67 mg g⁻¹ in the 10 species of mushrooms, where the edible mushrooms contained 66.68 mg g⁻¹ and the medicinal mushrooms contained 26.65 mg g⁻¹. The carbohydrates constituents of the 10 mushroom species were mainly mannose (36.23%), glucose (34.70%), and xylose (16.83%).     

Effect of phosphorus on the fruit yield and food value of two landraces of Trichosanthes cucumerina L.- Cucurbitaceae

Studies were conducted in the early season of 2002 and 2003 at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Nigeria to evaluate the effect of phosphorus (P) on fruit yield and chemical composition of two landraces of Trichosanthes cucumerina L. For the purpose of the study, two landraces of T. cucumerina named Landrace I and Landrace II were used. The five levels of phosphorus evaluated were 0, 30, 60, 90 and 120 kg P₂O₅ ha⁻¹ using single super phosphate fertilizer (8% P). Statistical analysis showed that 90 kg P₂O₅ ha⁻¹ gave statistically significant higher fruit yield (16.4 tons ha⁻¹) compared to other P levels. The fruit yield of the two Landraces did not differ significantly. Except for crude protein content, the 90 kg P₂O₅ ha⁻¹ produced significantly higher ether extract (1.22 g 100 g⁻¹), crude fibre (1.93 g 100 g⁻¹), moisture content (90.5 g 100 g⁻¹), ash (0.90 g 100 g⁻¹), total sugars (0.81 g 100 g⁻¹) and ascorbic acid (28.7 mg 100 g⁻¹) than other P levels. The essential amino acids compositions were also significantly higher at 90 g 100 g⁻¹ compared to other lower P levels. Landrace I had significantly higher ether extract (0.90 g 100 g⁻¹) content than Landrace II (0.62 g 100 g⁻¹) while Landrace II in turn had significantly higher total sugar (0.76 g 100 g⁻¹) compared to Landrace I (0.61 g 100 g⁻¹). The essential amino acids composition is high and the oxalate composition is low. The high ascorbic acid and amino acid content together with a low oxalate composition suggested a strong basis for encouraging the cultivation of this indigenous fruit vegetable to augment nutrient requirement, improve diet and consequently alleviate poverty, preserve the biodiversity and increase the gene bank of neglected wild species of high quality nutrient sources.     

Phenolic content and antioxidant capacity of tropical highland blackberry (Rubus adenotrichus Schltdl.) during three edible maturity stages

Tropical highland blackberry (Rubus adenotrichus Schltdl.) is a good source of antioxidants and contains appreciable levels of phenolic compounds, mainly ellagitannins and anthocyanins. This study examined the influence of three ripening stages on phenolic contents. Major anthocyanin pigments increased from 0.20 (red fruit) to 1.34 mg g⁻¹ fresh weight (FW) (fully ripe fruit), whereas ellagitannins and ellagic acid derivatives dropped from 3.8 to 2.2 mg ellagic acid equivalents g⁻¹ (FW). Flavonols also dropped from 5.1 to 2.0 mg quercetin equivalents 100 g⁻¹ (FW). Consequently, values for total phenolic compounds ranged from 5.8 to 5.2 mg gallic acid equivalents g⁻¹ (FW), showing no specific trend. Antioxidant activity (H-ORAC) increased from 38.29 to 64.00 μmol of Trolox equivalents g⁻¹ (FW) during ripening. When compared with other commercial cultivars, R. adenotrichus stands out for high H-ORAC value, although comparatively it possesses low anthocyanin content and average total phenolic content.     

Phenolic acid profiles of mangosteen fruits (Garcinia mangostana)

The composition of phenolic acids in various parts of mangosteen fruit (Garcinia mangostana) was determined by GC and MS. The total content of phenolic acids, identified by GC-FID ranged from 265.7 ± 12.7 (aril) to 5027.7 ± 188.0 (peel) mg per kg of dry matter of sample. Ten phenolic acids were identified in mangosteen fruit. Of these, protocatechuic acid was the major phenolic acid in the peel and rind, while p-hydroxybenzoic acid was the predominant phenolic acid in the aril. m-Hydroxybenzoic acid was detected only in the peel, while 3,4-dihydroxymandelic was present only in the rind. The phenolic acids liberated from esters and glycosidic bonds were the major fractions of phenolic acids in mangosteen fruit.     

Estimation of neuroprotective effects of Laurocerasus officinalis Roem. (cherry laurel) by in vitro methods

Dichloromethane, ethyl acetate, acetone, methanol, and water extracts prepared from the fruits and leaves of Laurocerasus officinalis Roem. (LO) (Rosaceae) were screened for their cholinesterase inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), the key enzymes in pathogenesis of Alzheimer's disease (AD), using ELISA microplate reader at 50, 100, and 200 ??g mL⁻¹. As AD is associated with oxidative stress, the antioxidant activity of the extracts was also tested by radical-forming methods against 2,2-diphenyl-1-picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylendiamine (DMPD), and superoxide radicals as well as iron-related methods; iron-chelating capacity and ferric-reducing antioxidant power (FRAP) assays. Total phenol and flavonoid quantification was achieved using Folin-Ciocalteau and AlCl₃ reagents, respectively. The highest AChE (44.01 ± 1.75%) and BChE (19.91 ± 0.37%) inhibition was caused by the LO-leaf-methanol extract 200 ??g mL⁻¹, while it showed the best radical-scavenging activity against DPPH at 2000 ??g mL⁻¹. Only, the dichloromethane and water extracts of the fruits and the leaf water extract had an iron-chelating capacity, while the leaf methanol extract displayed the highest FRAP. The leaf methanol extract (113.45 ± 0.71 mg g⁻¹ extract) was found to be the richest in total phenols, while the leaf acetone extract (139.90 ± 4.64 mg g⁻¹ extract) had the most abundant amount of total flavonoids.     

Phenolic compounds and fatty acids in different parts of Vitis labrusca and V. vinifera grapes

trans-Resveratrol, antioxidant activity, phenolic compounds, proximate composition, and fatty-acid composition were quantified in different parts (peel, pulp, and seeds) of four grape varieties: Brazil (Vitis vinifera), Benitaka (V. vinifera), Isabel (Vitis labrusca) and Niagara (V. labrusca). Large concentrations of polyunsaturated fatty acid (18.84 and 9204.27 mg 100 g^− 1), linoleic acid (LA, 18:2n-6), from 5890.87 to 9148.93 mg 100 g^− 1, and alpha-linolenic (LNA, 18:3n-3), from 5.25 to 56.85 mg 100 g^− 1, were found in different parts of the four grape varieties. The lowest concentrations necessary for 50% inhibition of DPPH were (9.26 to 126.91 ??g mL^− 1) in seeds; the pulp did not have antioxidant activity. The total phenolic content varied between 0.04 and 122.35 mg EAG g^− 1; seeds had the highest concentrations (89.83 to 122.35 mg EAG g^− 1), especially in Niagara and Isabel varieties. trans-Resveratrol was detected in peels (1.17 to 12.96 ??g g^− 1) and seeds (2.03 to 2.44 ??g g^− 1) of the four varieties; however, it was absent in the pulp.     

In vitro absorption and antiproliferative activities of monomeric and polymeric anthocyanin fractions from açai fruit (Euterpe oleracea Mart.)

Anthocyanins are among the most important and widely consumed natural pigments in foods, and have attracted increased attention as natural food colourants and potent bioactive agents. However, anthocyanins are generally unstable and may undergo chemical changes that include oxidative and polymerisation reactions during processing and storage. The role of anthocyanin polymerisation reactions on in vitro intestinal absorption and anti-cancer properties has not been assessed. This study investigated the chemical composition, antioxidant properties, antiproliferative activity, and in vitro absorption of monomeric and polymeric anthocyanin fractions from açai fruit (Euterpe oleracea Mart.). Cyanidin-3-rutinoside (58.5 ± 4.6%) and cyanidin-3-glucoside (41.5 ± 1.1%) were the predominant compounds found in monomeric fractions, while a mixture of anthocyanin adducts were found in polymeric fractions and characterised using HPLC–ESI-MSⁿ analyses. Monomeric fractions (0.5–100 μg cyanidin-3-glucoside equivalents/ml) inhibited HT-29 colon cancer cell proliferation by up to 95.2% while polymeric anthocyanin fractions (0.5–100 μg cyanidin-3-glucoside equivalents/ml) induced up to 92.3% inhibition. In vitro absorption trials using Caco-2 intestinal cell monolayers demonstrated that cyanidin-3-glucoside and cyanidin-3-rutinoside were similarly transported from the apical to the basolateral side of the cell monolayers (0.5–4.9% efficiency), while no polymeric anthocyanins were transported following incubation for up to 2 h. The addition of polymeric anthocyanin fractions also decreased monomeric anthocyanin transport by up to 40.3 ± 2.8%. Results from this study provide novel information regarding the relative size, absorption, and bioactive properties of anthocyanin monomers and polymer adducts.     

Influence of strawberry tree (Arbutus unedo L.) fruit ripening stage on chemical composition and antioxidant activity

Arbutus unedo is a widespread shrub with economic importance, derived from the use of its berries in the production of alcoholic beverages and in folk medicine. This work intends to evaluate for the first time the effect of fruit ripening stage on antioxidant activity, total phenolic content, fatty acid profile and tocopherol composition. Ripe fruits shown higher extraction yield (45.04 ± 2.23%) when compared to other fruit ripening stages. By contrast, total phenol contents were higher in the unripe and intermediate stage of ripeness (108 and 111 mg GAES/g dry fruit, respectively, against 60 mg/g dry fruit when ripe). Ripe and intermediate fruits shown the lower EC₅₀ values on the DPPH radicals (0.25 ± 0.02 mg/mL) and reducing power assay (1.09 ± 0.05 mg/mL), respectively. A significant correlation was established between antioxidant activity and fruits ripening stage. Fatty acid profiles were very similar between the ripening stages, being alfa-linolenic, linoleic and oleic, the three major ones. Polyunsaturated fatty acids (PUFA) represent as much as 60% of the total fatty acids, with a highly favorable omega 3/omega 6 ratio. From the analysis of the vitamin E vitamers, the most important was ??-tocotrienol, with a clear reduction in the total free vitamin E content with ripening.These results highlight that the fruits of intermediate ripeness can be regarded important sources of biologically active compounds with a fatty acid profile rich in omega-3 PUFA, properly supplemented with high vitamin E amounts.     

Polyphenolic composition and content in the ripe berries of wild Vitis species

To explore wild genetic resources for improving fruit and processing quality of cultivated grape cultivars, the polyphenolic composition and content in the ripe berries of 147 grape accessions from 16 Vitis species for two consecutive years were characterised. A total of 48 polyphenolic compounds, including 28 anthocyanins, 6 flavonols, 6 flavanols, 6 hydroxycinnamic derivatives, and 2 hydroxybenzoic acids, were identified via HPLC-MS and quantified by HPLC-DAD. These wild grape species had unique presence of abundant di-glucoside derivatives of anthocyanins. In addition, anthocyanins in most wild species were predominantly nonacylated. The mean contents for anthocyanins, flavanols, flavonols, hydroxycinnamic derivatives, and hydroxybenzoic acids were 9.610, 0.769, 0.093, 0.441 and 0.027 mg g⁻¹ FW, respectively. They were about 2 to 10 folds higher than their respective counterparts in the most widely cultivated grape species Vitis vinifera. As expected, most of these groups of compounds were correlated negatively with berry weight, but positively with the content of total soluble solids.     

Optimization of the extraction of flavanols and anthocyanins from the fruit pulp of Euterpe edulis using the response surface methodology

The response surface methodology (RSM) was employed to optimize the ultrasound extraction of flavanols and anthocyanins from the pulp of jussara (Euterpe edulis), using a second-order polynomial equation to describe the experimental data for total flavanol (TF), total phenolic (TP), and total monomeric anthocyanin (TMA) contents, as well as the total antioxidant activity (TAA). A central composite design with two-variables (extraction time and solid to liquid ratio) was then applied. The optimized conditions that maximized the yields of flavanol-enriched extract were a solvent methanol/0.1 M HCl, solid to liquid ratio of between 1:50 and 1:100 and extraction time of 15 min. For anthocyanin-enriched extracts the respective optimal parameters were a solvent methanol/1.5 M HCl, solid to liquid ratio of between 1:30 and 1:50 and extraction time of 24 h. The results showed good fits with the proposed model for both the flavanol-enriched extract (R² = 0.94) and for the anthocyanin-enriched extract (R² = 0.99).     

Polyphenol composition, vitamin C content and antioxidant capacity of Mauritian citrus fruit pulps

The pulp extracts of twenty-one varieties of citrus fruits (oranges, satsumah, clementine, mandarins, tangor, bergamot, lemon, tangelos, kumquat, calamondin and pamplemousses), commonly grown in Mauritius, were characterised in terms of their total soluble solids (TSS), titratable acidity (TA), polyphenol composition and vitamin C contents. Total phenolics ranged from 406.3 ± 14 to 1694 ± 19 ??g g^− 1 fresh weight (FW). Total flavonoids varied between 133 ± 6 and 965 ± 7 ??g g^− 1 FW and vitamin C contents were from 166 ± 19 ??g/mL to 677 ± 22 ??g/mL. The pulp of a pamplemousse variety had the highest TSS/TA ratio whereas lemon pulps had lowest TSS/TA ratios. The antioxidant activities of the pulp extracts were assessed and total phenolics correlated strongly with the trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant capacity (FRAP) and hypochlorous acid (HOCl) scavenging activity assays. Based on their antioxidant activities, nine citrus fruits namely, one orange, tangor, kumquat, calamondin and pamplemousse variety and two mandarin and tangelo varieties were further characterised for their flavanone, flavonol and flavone levels by HPLC. Hesperidin (6.89 ± 0.06 to 26.98 ± 0.07 mg/g FW) and narirutin (0.27 ± 0.01 and 20.91 ± 0.10 mg/g FW) were present at high concentrations compared to the other flavonoid glycosides in the pulp extracts. Naringin was detected only in pulp extracts of pamplemousses. In the light of the data obtained, citrus fruit pulps represent an important source of phytochemicals with potent antioxidant capacity.     

Near infrared reflectance spectroscopy predicts the content of polyunsaturated fatty acids and biohydrogenation products in the subcutaneous fat of beef cows fed flaxseed

This study examined the ability of near infrared reflectance spectroscopy (NIRS) to estimate the concentration of polyunsaturated fatty acids and their biohydrogenation products in the subcutaneous fat of beef cows fed flaxseed. Subcutaneous fat samples at the 12th rib of 62 cows were stored at − 80 °C, thawed, scanned over a NIR spectral range from 400 to 2498 nm at 31 °C and 2 °C, and subsequently analysed for fatty acid composition. Best NIRS calibrations were with samples at 31 °C, showing high predictability for most of the n−3 (R²: 0.81-0.86; RMSECV: 0.11-1.56 mg g^− 1 fat) and linolenic acid biohydrogenation products such as conjugated linolenic acids, conjugated linoleic acids (CLA), non-CLA dienes and trans-monounsaturated fatty acids with R² (RMSECV_, mg g^− 1 fat) of 0.85-0.85 (0.16-0.37), 0.84-0.90 (0.21-2.58), 0.90 (5.49) and 0.84-0.90 (4.24-8.83), respectively. NIRS could discriminate 100% of subcutaneous fat samples from beef cows fed diets with and without flaxseed.