Photochemiluminescence Assay Research Articles

Investigation on the antioxidant compounds and antioxidant capacity of Romanian Prunus species

The current investigation delineates the application of the photochemiluminescence assay in two distinct extracts, namely hydrophilic and lipophilic, alongside the utilization of the DPPH method to quantify the antioxidative potential of five fruits belonging to the Prunus genus (sweet cherry, sour cherry, apricot, peach and plum). The findings of this study revealed that the analyzed fruit samples exhibited noticeable concentrations of phenolic compounds ranging from 31.14 ± 0.29 to 171.61 ± 0.98 mg of Gallic Acid Equivalent per 100 g of fresh weight. In reference to the flavonoid content, the observed concentrations ranged from 8.61±0.19 to 22.15 ± 0.31 mg Rutin Equivalent per 100 g fresh weight, whereas the anthocyanin content displayed concentrations ranging between 0.26 ± 0.01 and 5.26 ± 0.51 mg cyanidin-3-glucoside equivalent per 100 g fresh weight. Remarkably, the sour cherry exhibited the highest antioxidant capacity among the tested fruits in both hydrophilic and lipophilic systems, followed by sweet cherry and apricot.

Antioxidant content and volatile composition of seedless table grape (Vitis vinifera L.) varieties

Grapes are important sources of phenolics, which are recognized to possess high biological value. In this work, we evaluated the total phenol content (TPC), total anthocyanin content (TAC), antioxidant activity (AA) and volatile composition of unstudied seedless table grape varieties (i.e., Autumn Crisp and Pristine as white cultivars, Scarlotta and Crimson as red cultivars and Adora and Melody as black cultivars). As a result, Adora and Melody exhibited higher TPCs, TACs and AA, measured by the 2,2-diphenyl-2-picrylhydrazil (DPPH) and photochemiluminescence (PCL) assays, than the rest of the varieties. A comparison between the two black cultivars proved that Adora possessed higher TPC (62.70 mg GAE 100 g−1), DPPH radical scavenging activity (IC50 of 3.69 mg ml−1) and PCL antiradical activity (72.14 µg Trolox ml−1) than Melody (47.30 mg GAE 100 g−1, IC50 of 5.0 mg ml−1 and 42.36 µg Trolox ml−1, respectively). The volatile composition, determined by solid phase microextraction (SPME)–gas chromatography/mass spectrometry (GC/MS), indicated a similar qualitative aroma profile for all varieties. However, quantitative differences were measured among them, which were reflected in distinct sensory perception by sensorial testing. From these results, Adora was selected for its antioxidant properties and flavor characteristics.

Evaluation of bioactive compounds and antioxidant capacity of Romanian berries

The objective of this paper was to evaluate seven different berries most consumed in Romania in order to determine the bioactive compounds: total phenolics content, total flavonoid content, total anthocyanins content, antioxidant activity by DPPH and total antioxidant capacity (water-soluble and lipid-soluble by photochemiluminescence assay, PCL). The analyzed fruits contain significant amounts of phenolic compounds between 18.91 and 383.06 mg gallic acid equivalents per 100 grams of fresh berries. Black currant extract had the highest content of total phenolic compounds, 383.06 mg GAE/100g, while the lowest level was obtained for the gooseberry, 18.91 mg GAE/100g. DPPH values varied between 22.15 and 892.35μmol Trolox Equivalent/100g fresh berries. Strong positive correlations between the antioxidant capacity of lipid-soluble compounds measured by PCL and DPPH was found (r= 0.9153). The results obtained demonstrated that different Romanian berries studied show a great antioxidant activity with possible benefits on human health.

Phenolic Compounds, Vitamins C and E and Antioxidant Activity of Edible Honeysuckle Berries (Lonicera caerulea L. var. kamtschatica Pojark) in Relation to Their Origin.

Honeysuckles are frost tolerant plants providing early-ripening fruits with health-promoting properties which have been used in traditional medicine in China. This study evaluates the impact of the climatic conditions of two areas on the chemical composition and antioxidant activity (AOA; by DPPH—2,2-diphenyl-1-picrylhydrazyl and photochemiluminescence assays) of eight cultivars of honeysuckle berries (Lonicera caerulea L. var. kamtschatica Pojark) of various ripening times. Expectedly, chemical composition and AOA values varied depending on the cultivars, locality and selected methods. Berries from Lednice (the area with more sunshine) showed higher average contents of total monomeric anthocyanins (TMAC; pH differential absorbance method), vitamins C and E and total phenolics (high-performance liquid chromatography). In contrast, berries from Žabčice (the area with more rain) performed higher average contents of total phenolics and flavonoids (UV/VIS spectroscopic analyses). Interestingly, fundamental amounts of chlorogenic acid were determined irrespective of the locality. Regarding TMAC and vitamin C content, early ripening Amphora from both areas has been assessed as the best cultivar; concerning the content of phenolic compounds, Fialka from both areas and Amphora from Lednice is considered as the most valuable. The obtained results may facilitate the selection of the most valuable cultivars for both producers and consumers.

Byproducts (Flour, Meals, and Groats) from the Vegetable Oil Industry as a Potential Source of Antioxidants.

The present study presents the use of photochemiluminescence assay (PCL) and 2,2 diphenyl-1-picryl-hydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), the ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) methods for the measurement of lipid-soluble antioxidant capacity (ACL) of 14 different byproducts obtained from the vegetable oil industry (flour, meals, and groats). The research showed that the analyzed samples contain significant amounts of phenolic compounds between 1.54 and 74.85 mg gallic acid per gram of byproduct. Grape seed flour extract had the highest content of total phenolic compounds, 74.85 mg GAE/g, while the lowest level was obtained for the sunflower groats, 1.54 mg GAE/g. DPPH values varied between 7.58 and 7182.53 mg Trolox/g of byproduct, and the highest antioxidant capacity corresponded to the grape seed flour (7182.53 mg Trolox/g), followed by walnut flour (1257.49 mg Trolox/g) and rapeseed meals (647.29 mg Trolox/g). Values of ABTS assay of analyzed samples were between 0 and 3500.52 mg Trolox/g of byproduct. Grape seed flour had the highest value of ABTS (3500.52 mg Trolox/g), followed by walnut flower (1423.98) and sea buckthorn flour (419.46). The highest values for FRAP method were represented by grape seed flour (4716.75 mg Trolox/g), followed by sunflower meals (1350.86 mg Trolox/g) and rapeseed flour (1034.92 mg Trolox/g). For CUPRAC assay, grape seed flour (5936.76 mg Trolox/g) and walnut flour (1202.75 mg Trolox/g) showed the highest antioxidant activity. To assess which method of determining antioxidant activity is most appropriate for the byproducts analyzed, relative antioxidant capacity index (RACI) was calculated. Depending on the RACI value of the analyzed byproducts, the rank of antioxidant capacity ranged from −209.46 (walnut flour) to 184.20 (grape seed flour). The most sensitive methods in developing RACI were FRAP (r = 0.5795) and DPPH (r = 0.5766), followed by CUPRAC (r = 0.5578) and ABTS (r = 0.4449), respectively. Strong positive correlations between the antioxidant capacity of lipid-soluble compounds measured by PCL and other methods used for determining antioxidant activity were found (r > 0.9). Analyses have shown that the different types of byproducts obtained from the vegetable oil industry have a high antioxidant activity rich in phenolic compounds, and thus their use in bakery products can improve their nutritional quality.

Characterisation of Muffins with Upcycled Sunflower Flour.

There is an increased interest and need to make our economy more circular and our diets healthier and more sustainable. One way to achieve this is to develop upcycled foods that contain food industry by-products in their formulation. In this context, the aim of this study was to develop muffins containing upcycled sunflower flour (a by-product from the sunflower oil industry) and assess the effects of sunflower flour addition on the fibre, protein, amino acid, mineral content, and antioxidant activity measured by a Ferric Reducing Antioxidant Power (FRAP) assay and Photo chemiluminescence (PCL) assay. Results show that the sunflower flour inclusion significantly improved all the parameters analysed as part of this study. A more balanced muffin amino acid profile was achieved, thanks to the increased levels of lysine, threonine, and methionine, the limiting essential amino acids of wheat flour. We can conclude that upcycled ingredients, such as sunflower flour, could be used for the nutritional improvement of baked goods, such as muffins. Their addition can result in several nutritional advantages that could be communicated on packaging through the use of the appropriate EU nutrition claims, such as those on protein, fibre, and mineral content.

DPPH free-radical scavenging activity, total phenolic contents and chemical composition analysis of forty-two kinds of essential oils

Forty-two commonly used essential oils were investigated for the antioxidant capabilities by DPPH free-radical scavenging activity, total phenolic contents and photochemiluminescence (PCL) assay. At the concentration of 5 mg/mL, cinnamon bark (91.4 ± 0.002%), origanum (86.66 ± 0.008%) and thyme wild (52.54 ± 0.016%) were shown to own the strongest DPPH free-radical scavenging activity. Their total phenolic contents were 658.40 ± 4.383, 1107.20 ± 0.768 and 275.50 ± 0.607 (μg GAE / 5 mg essential oil), respectively. To compare with the standard reference BHA (μg/mL), their EC50 were in the order: BHA (25.11 μg/mL) < cinnamon bark (90.63 μg/mL) origanum (62.63 ± 1.73 μmol trolox/g) > theme wild (5.88 ± 0.16 μmol trolox/g). The chemical compositions of cinnamon bark, origanum and thyme wild were analyzed by GC-MS and followed by DPPH free-radical scavenging activity assay to confirm that eugenol, carvacrol and thymol were the major compositions contributing the antioxidative capabilities of the essential oils.

Characterisation of the total phenolic, vitamins C and E content and antioxidant properties of the beebread and honey from the same batch

The aim of this study was to compare total phenolic and flavonoid content, antioxidant and reducing activity, as well as vitamin C and E content in beebread and honey. The antioxidant activity of samples was determined by photochemiluminescence (PCL) assay, while reducing potential was measured using FRAP and ORAC assays. Vitamin C was analysed by HPLC–MS-TripleTOF method and vitamin E by HPLC-DAD. Beebread was characterised by the higher level of the total phenolic (~90%), flavonoid (~97%), vitamin C (~99%) and E (~98%) as compared to the honey. The data showed that beebread had also higher values of antioxidant activity and reducing potential by ~99% and ~41–98%, respectively, than honey. Our findings indicate that beebread is valuable source of bioactive substances, with the high beneficial properties.

Capitalization of sea buckthorn waste by fermentation: Optimization of industrial process of obtaining a novel refreshing drink

This paper provides a solution for the management of waste from the sea buckthorn (Hippophae rhamnoides L.) processing industry. The application of fermentation technology on this practically nonvalue sea buckthorn material leads to the attainment of a novel beverage with functional properties. The optimum production conditions of a fermented low-alcoholic drink from sea buckthorn waste by Saccharomyces cerevisiae were determined. Response surface methodology coupled with Box–Behnken design was employed for the optimization studies. The study revealed an optimum inoculum size of 0.2% at fermentation temperature of 23.3 °C for 72 hr for obtaining a 3% of ethanol sea buckthorn beverage, with no microbial load of the samples during fermentation process. Quadratic polynomial models could predict and describe the physico-chemical responses of the final product. Furthermore, the high-performance liquid chromatography and photochemiluminescence assays revealed the functional properties of the obtained beverage, which had an important amount of phenolic compounds and high antioxidant activity. Practical applications This study proves that sea buckthorn waste can act as a suitable substrate for fermentation, resulting in a novel sea buckthorn beverage, which is not only refreshing and energizing (due to its content in carbon dioxide and low level of ethanol), but also healthy. Mathematical models described are of high importance for process conditions selection and response prediction in industrial environment. Therefore, this study provides useful information for the fermented drinks industry, helping beverage processing industries achieve optimum yield in low alcoholic wine production using sea buckthorn waste as sole substrate.

Inhibition of Advanced Glycation End-Product Formation by High Antioxidant-Leveled Spices Commonly Used in European Cuisine.

Spices and herbs, as good sources of polyphenols, could be strong inhibitors of advanced glycation end-product (AGE) formation. The aim of this research was to measure the ability of various spices to inhibit AGEs and to study the correlation of AGE inhibition with total phenolic (TP) content and antioxidant capacity. Fourteen spices commonly used in European cuisine were extracted with a 50% ethanol solution, and their water and total phenolic contents and antioxidant capacities were examined. Antioxidant capacity was evaluated using three methods: (1) Measurement of the radical scavenging ability of 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and (2) 2,2-diphenyl-1-picrylhydrazyl (DPPH●); and (3) photochemiluminescence (PCL) assay. Antiglycation properties were studied in vivo using two model systems: Bovine serum albumin-glucose (BSA-glucose) and bovine serum albumin-methylglyoxal (BSA-MGO). The most potent glycation inhibitors, according to the BSA-MGO assay, were star anise (88%), cinnamon (85%), allspice (81%), and cloves (79%), whereas in the BSA-glucose measurement, oregano was noted to be a very effective inhibitor of the glycation process. The ability to inhibit glycation was highly correlated with TP values in the BSA-MGO and BSA-glucose assay (r = 0.84 and 0.76, respectively). Our research showed the high antiglycation ability of cinnamon, cloves, and allspice, and we suggest, for the first time, that anise could also be considered a good glycation inhibitor.

Phenolic Composition and Antioxidant Activities of Soybean (Glycine max (L.) Merr.) Plant during Growth Cycle

It is important to identify the growth stage at which the plant has the maximum antioxidant properties for the production of bioactive compounds from crops or agricultural by-products or for forage as a possible source of antioxidants in livestock. Therefore, we investigated the phenolic composition and antioxidant capacity of the aerial part of soybean at seven stages classified as vegetative stages (V5 and V6) and reproductive stages (R1, R2, R3, R4, and R5). Aqueous-methanol extracts were evaluated for their total phenolic content (TPC), ferric-reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), antioxidant activity as determined by photochemiluminescence assay (PCL-ACL), Fe2+ chelating ability, and antiradical activity against DPPH•. The extracts with the highest TPC content were obtained at stages V6 and R5. The phenolic compounds profile, as determined by DAD-HPLC, was characterized by 19 compounds, that differed significantly by growth stage (p &lt; 0.05). Antioxidant tests showed significant differences among stages (p &lt; 0.05). The lowest TEAC value was found for the R2 stage and the highest values for the R3 and R1 stages. FRAP values ranged from 623 to 780 μmol Fe2+/g extract. PCL-ACL values ranged from 516 to 560 μmol Trolox eq./g extract; Fe2+ chelation ability ranged from 36.5 to 51.7%. The highest antiradical activity against DPPH• was found in the extract from the V5 stage, which had the lowest EC50 value. The extracts of soybean plant can be used in pharmacy for the production of nutraceuticals by virtue of their good antioxidant activity and content of flavonols and other bioactive constituents.

Determination of polyphenol component fractions and integral antioxidant capacity of Syrian aniseed and fennel seed extracts using GC–MS, HPLC analysis, and photochemiluminescence assay

The chemical components of both Syrian aniseed and fennel seeds collected from Idlib and Aleppo regions were identified using GC/MS spectrometry. Thirty-four component fractions representing an average of 98.5% of anise seed extract were characterized. The major average components were (E)-Anethole, Estragole, Limonene, Fenchone, Linalool, para-Anisaldehyde, (Z)-Anethole, and methyl chavicol. Also, thirty-one component fractions representing an average of 99.46% of fennel seed extract were identified. The major components were α-Pinene, α-Phellandrene, Fenchone, Methyl chavicol, Estragole, (Z)-Anethole, Limonene, 1,8-Cineole, Anisole-p-allyl, E,E-Farnesene, Estragole, (E)-Anethole, Anisaldehyde, and Carvacrol. The extract of aniseed was characterized by higher amounts of trans-anethole (52.2%) than fennel extract (38.3%). The integral antioxidant capacity (IAC) of two different extracts from both aniseed and fennel seeds have been determined using photochemiluminescence assay (PCL). The sum of antioxidant capacity (IAC) of hydrophilic and hydrophobic components in both aniseed and fennel seeds was determined, as a total equivalent per gram of dry material (nmolTE/gDM) at 166.69 ± 0.42 and 363.28 ± 1.11 nmol for hydrophilic and hydrophobic components, respectively. Eight major phenolic compounds known as possible antioxidant sources with their concentrations have been identified in both aniseed and fennel seeds by HPLC and GC–MS analysis.

The Use of the PHOTOCHEM Device in Evaluation of Antioxidant Activity of Polish Honey

Forty samples of varietal Polish honeys were investigated in order to assess their antioxidant capacity by photochemiluminescence (PCL) methods using standard ACW and ACL kits. The reference methods, FRAP and DPPH, were used. The total phenolics content (TPC) by Folin-Ciocalteau method was determined. The antioxidant properties of honeys as well as TPC were mainly dependent on honey botanical origin. The highest phenolic content and antioxidant activity for dark honeys, while the lowest for white honeys, were found. Moreover, the results obtained by used analytical methods were comparable and the best correlation between PCL and FRAP (r > 0.81) and DPPH (r = 0.74) methods was observed. The TPC in honeys was positively correlated with its antioxidant activity measured by PCL (r > 0.76). Used for the first time, PCL assay demonstrated usefulness in determining the antioxidant capacity of honey, divided into water-and lipid-soluble fractions, measured by ACW and ACL kits, respectively.

Use of Different Proteases to Obtain Flaxseed Protein Hydrolysates with Antioxidant Activity.

The antioxidant activity of flaxseed protein hydrolysates obtained using five different enzymes was evaluated. Proteins were isolated from flaxseed cake and were separately treated with papain, trypsin, pancreatin, Alcalase and Flavourzyme. The degree of hydrolysis (DH) was determined as the percentage of cleaved peptide bonds using a spectrophotometric method with o-phthaldialdehyde. The distribution of the molecular weights (MW) of the hydrolysis products was profiled using Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Tricine-SDS-PAGE) and size exclusion-high performance liquid chromatography (SE-HPLC) separations. The antioxidant activities of the protein isolate and hydrolysates were probed for their radical scavenging activity using 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS•+) and photochemiluminescence (PCL-ACL) assays, and for their ferric reducing antioxidant power (FRAP) and ability to bind Fe2+. The hydrolysates were more effective as antioxidants than the protein isolate in all systems. The PCL-ACL values of the hydrolysates ranged from 7.2 to 35.7 μmol Trolox/g. Both the FRAP and ABTS•+ scavenging activity differed among the hydrolysates to a lower extent, with the ranges of 0.20–0.24 mmol Fe2+/g and 0.17–0.22 mmol Trolox/g, respectively. The highest chelating activity (71.5%) was noted for the pancreatin hydrolysate. In general, the hydrolysates obtained using Alcalase and pancreatin had the highest antioxidant activity, even though their DH (15.4% and 29.3%, respectively) and the MW profiles of the peptides varied substantially. The O2•− scavenging activity and the ability to chelate Fe2+ of the Flavourzyme hydrolysate were lower than those of the Alcalase and pancreatin hydrolysates. Papain was the least effective in releasing the peptides with antioxidant activity. The study showed that the type of enzyme used for flaxseed protein hydrolysis determines the antioxidant activity of the hydrolysates.

Classification of Sunflower Oil Blends Stabilized by Oleoresin Rosemary (Rosmarinus officinalis L.) Using Multivariate Kinetic Approach.

The sunflower oil-oleoresin rosemary (Rosmarinus officinalis L.) blends (SORB) at 9 different concentrations (200 to 2000 mg/kg), sunflower oil-tertiary butyl hydroquinone (SOTBHQ ) at 200 mg/kg and control (without preservatives) (SO control ) were oxidized using Rancimat (temperature: 100 to 130 °C; airflow rate: 20 L/h). The oxidative stability of blends was expressed using induction period (IP), oil stability index and photochemiluminescence assay. The linear regression models were generated by plotting ln IP with temperature to estimate the shelf life at 20 °C (SL20 ; R(2) > 0.90). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) was used to classify the oil blends depending upon the oxidative stability and kinetic parameters. The Arrhenius equation adequately described the temperature-dependent kinetics (R(2) > 0.90, P < 0.05) and kinetic parameters viz. activation energies, activation enthalpies, and entropies were calculated in the range of 92.07 to 100.50 kJ/mol, 88.85 to 97.28 kJ/mol, -33.33 to -1.13 J/mol K, respectively. Using PCA, a satisfactory discrimination was noted among SORB, SOTBHQ , and SOcontrol samples. HCA classified the oil blends into 3 different clusters (I, II, and III) where SORB1200 and SORB1500 were grouped together in close proximity with SOTBHQ indicating the comparable oxidative stability. The SL20 was estimated to be 3790, 6974, and 4179 h for SO control, SOTBHQ, and SORB1500, respectively. The multivariate kinetic approach effectively screened SORB1500 as the best blend conferring the highest oxidative stability to sunflower oil. This approach can be adopted for quick and reliable estimation of the oxidative stability of oil samples.

Interactions between lipophilic antioxidants measured by photochemiluminescence assay and α-tocopherol equivalent antioxidant capacity assay as well as the influence of matrix compounds on the lipophilic antioxidant capacity

Antioxidant capacity as sum parameter necessarily includes interactions between antioxidants. Thus, two compounds out of α-tocopherol, lycopene, β-carotene and lutein were mixed and measured by lipophilic photochemiluminescence (PCL) assay and α-TEAC assay. In the α-TEAC assay, all mixtures showed an antagonistic effect. The highest antagonistic effect was found for all mixtures of β-carotene and lutein. In contrast, in the PCL system antagonistic, synergistic and additive effects were detected. The mixture β-carotene and lutein 2:1 had the highest synergistic effects. The presence of functional hydroxyl groups and hydrogen bonding effects may have an influence on the interactions. In both assays used, we observed a concentration-dependent effect.The influences of glucose, fructose, saccharose and starch on the antioxidant capacity were determined by PCL and α-TEAC, too. All sugars can have an effect on the lipophilic antioxidant capacity depending on the extraction solvent. The sugar samples, extracted with n-hexane, did not show any antioxidant capacity in α-TEAC assay. In the PCL, the antioxidant potentials of sugars were dependent on the extraction solvent and reflected the dissolubility of sugars in methanol. The better the solubility the higher the antioxidant capacity. Additionally, sugars did not interact with antioxidants, with exception of the methanolic fructose extract.

The impact of red cabbage fermentation on bioavailability of anthocyanins and antioxidant capacity of human plasma

The effect of red cabbage fermentation on anthocyanin bioavailability and plasma antioxidant capacity in humans was studied. In a randomized crossover study, 13 volunteers consumed fresh and fermented red cabbage. Blood and urine samples were collected before and after consumption. Analyses of anthocyanins by HPLC–MS/MS and plasma antioxidant capacity by photochemiluminescence assay were conducted. Red cabbage products contained 20 different nonacylated and acylated anthocyanins with the main structure of cyanidin triglucosides. The anthocyanins ingested were present in physiological fluids in form of 18 native anthocyanins and 12 metabolites (methylated, glucuronided, sulfated). Among cyanidin metabolites identified, methylated forms were predominant. Bioavailability of anthocyanin from fresh red cabbage was over 10% higher than from fermented red cabbage. Upon fresh cabbage consumption, volunteers plasma showed higher antioxidant capacity than after fermented cabbage intake. The study has shown that fermentation process affects red cabbage anthocyanins bioavailability and human plasma antioxidant capacity.

Multivariate Analysis for Kinetic Modeling of Oxidative Stability and Shelf Life Estimation of Sunflower Oil Blended with Sage (Salvia officinalis) Extract Under Rancimat Conditions

In this research, sunflower oil-sage (Salvia officinalis) extract blends (SOSB) at nine different concentrations (200–2000 ppm), sunflower oil-tertiary butyl hydroquinone (TBHQ) (SOTBHQ) at 200 ppm, and control (no added antioxidant) were oxidized using Rancimat (temperature 100, 110, 120, and 130 °C; airflow rate 20 L/h). The resistance of the oil samples against oxidative stability was measured by induction period (IP). Oxidative stability index (OSI) and % antioxidant activity (AA) of oil samples were calculated and compared with photochemiluminescence (PCL) assay. The linear regression models were generated by plotting ln IP vs. temperature to estimate the shelf life as IP at 20 °C (R 2 > 0.90). The Arrhenius equation adequately described the temperature-dependent kinetics (R 2 > 0.90, p 0.90, p < 0.05) was obtained between OSI and PCL assay. The kinetic parameters together with multivariate analysis effectively screened 1200–1500 ppm of sage extract as the best concentration range conferring the highest oxidative stability to sunflower oil.

Fatty acid, carotenoid and tocopherol compositions of 20 Canadian lentil cultivars and synergistic contribution to antioxidant activities

Understanding the profile of lipophilic phytochemicals in lentils is necessary to better understand the health benefits of lentils. The fatty acid, carotenoid and tocopherol compositions and antioxidant activities of the lipophilic extracts of 20 lentil cultivars (10 red and 10 green) were therefore examined. Lentils contained 1.52–2.95% lipids, of which 77.5–81.7% were unsaturated essential fatty acids. Total tocopherols ranged from 37 to 64μg/g DW, predominantly γ-tocopherol (96–98% of the tocopherol content), followed by δ- and α-tocopherol. trans-Lutein was the primary and major carotenoid (64–78%) followed by trans-zeaxanthin (5–13%). Carotenoids and tocopherols showed weak correlation with 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity (r=0.4893 and 0.3259, respectively), but good correlation when combined (r=0.6688), suggesting they may act synergistically. Carotenoids were found to contribute the most to the strong antioxidant activity measured by photochemiluminescence (PCL) assay. Results from this study contribute to the development of lentil cultivars and related functional foods with increased health benefits.

SCREENING OF BIOLOGICAL ACTIVITIES FROM NOSTOC SPP. (CYANOPHYTA)

Screening of antioxidant activity (AA), total polysaccharide content (TPC) and angiotensin I-converting enzyme (ACE) inhibitor from Nostoc spp., maintained at TISTR Algal Culture Collection (TISTR-ACC) was conducted. The AA was tested by free radical scavenging of lipid phase (antioxidant capacity of lipid-soluble compounds-ACL) against superoxide anion (O2) using photochemiluminescence (PCL) assay. From seventy-one samples of crude extracts, N. punctiforme TISTR 8167 showed the best AA of 481.55 µmol (Trolox equivalent)/g (crude extract), followed by N. parmelioides TISTR 8174, Nostoc sp. TISTR 9102, N. paludosum TISTR 9004, Nostoc sp. TISTR 9073 and N. commune TISTR 8870, the activities of which were in the range of 348-390 µmol (Trolox equivalents)/g (crude extract). The total polysaccharide content (TPC) was determined by phenol-sulfuric acid assay. From fifty-two samples, the high TPC at ≥120 mg g-1 (dry cell weight), were found in three strains. The highest TPC at 130 mg g-1 was obtained from N. commune TISTR 8299. Angiotensin I-converting enzyme inhibitory activity (ACE-IA) and soluble protein content (SPC) of Nostoc strains were determined from 70 to 58 samples, respectively. The ACE-IA was tested by the detection of hippuric acid (HA) content from the reaction between hippuryl-histidyl-leucine (HHL) and ACE in the presence or absence of ACE inhibitor through simulated digestion of the samples. The results revealed that the high activities in the range 78-86% were obtained from N. commune TISTR 8160, N. muscorum TISTR 8164, N. paludosum TISTR 8890, N. entophylum TISTR 8161 and N. punctiforme TISTR 8167, by which N. commune TISTR 8160 expressed the highest inhibitory activity at 86%. The results of SPC quantified by Bradford assay were in the range 0.03-1.41 mg ml-1, N. micro-scopicum TISTR 9078, exhibited the highest SPC among the tested samples. However, these results show no relationship between ACE-IA and SPC.