Phenolic composition,antioxidant and antimicrobial activities of free and bound phenolic extracts of Moringa oleifera seed flour

Phenolic compounds, antioxidant and antibacterial activities of defatted Moringa oleifera seed flour (DMF) were investigated. The total phenolic and flavonoid contents were measured using colorimetric methods. Free phenolic acid and flavonoid profiles were analyzed by high performance liquid chromatography, while antioxidant capacities were evaluated using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power and total antioxidant capacity. The results showed that extractability of phenolic compounds was significantly higher (p < 0.05) in bound phenolic extract (4173.00 ± 32.22 mg gallic acid equivalents (GAE)/100 g) than in free phenolic extract (780.00 ± 14.2 mg GAE/100 g) and it showed higher antioxidant and antimicrobial activities. The IC₅₀ value for DPPH radical scavenging activity was 0.9 ± 0.05 and 14.9 ± 0.07 mg/mL for bound phenolic and free phenolic extracts, respectively. Bound phenolic extract was more effective (minimum inhibitory concentration (MIC), 0.06–0.157%) than free phenolic extract (MIC, 0.117–0.191%) against tested bacteria. Ten phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, caffeic acid, protocatechuic acid, cinnamic acid, catechin, epicatechin, vanillin and quercetin) were identified and quantified in both extracts. These natural plant phenolics from Moringa seeds could be a good source of antioxidants and antibacterials for food and pharmaceutical industries.     

Soluble phenolics and antioxidant properties of soybean (Glycine max L.) cultivars with varying seed coat colours

This research was the first to investigate nutritional components, including soluble phenolics (isoflavones and anthocyanins), protein, oil, and fatty acid as well as antioxidant activities in different coloured seed coat soybeans (yellow, black, brown, and green) for two crop years. The soluble phenolics differed significantly with cultivars, crop years, and seed coat colours, while protein, oil, and fatty acid exhibited only slight variations. Especially, malonylgenistin and cyanidin-3-O-glucoside compositions had the most remarkable variations. Green soybeans had the highest average isoflavone content (3079.42 μg/g), followed by yellow (2393.41 μg/g), and black soybeans (2373.97 μg/g), with brown soybeans showing the lowest value (1821.82 μg/g). Anthocyanins showed only in black soybeans, with the average contents of the primary anthocyanins, cyanidin-3-O-glucoside, delphinidine-3-O-glucoside, and petunidin-3-O-glucoside, quantified at 11.046, 1.971, and 0.557 mg/g, respectively. Additionally, Nogchae of green soybean and Geomjeongkong 2 of black soybean may be recommended as potential cultivars owing to the highest average isoflavone (4411.10 μg/g) and anthocyanin (21.537 mg/g) contents. The scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals also differed remarkably, depending upon isoflavone and anthocyanin contents, with black soybeans exhibiting the highest antioxidant effects.     

Evaluation of bioactive properties of Indian carrot (Daucus carota L.): A chemometric approach

Sixteen Indian commercial carrot cultivars were analysed for variations in β-carotene, total phenolics, total flavonoids, total monomeric anthocyanin and antioxidant activity. Antioxidant activity was measured using four in vitro assays viz. ferric reducing antioxidant power (FRAP), cupric reducing antioxidant power (CUPRAC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and Trolox equivalent antioxidant capacity assays (TEAC). Additionally six colour attributes were evaluated. Among carrot cultivars, significant differences (p < 0.05) were obtained with respect to antioxidant composition and antioxidant activity. Total phenols and total flavonoids varied from 7.98 to 291.48 mg/100 g fresh weight (fw) and 3.00 to 111.70 mg/100 g fw respectively. Chemometric tools like principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were applied to understand possible classification Indian carrot cultivars based on colour properties, bioactive antioxidant compounds and antioxidant potentiality. PCA revealed that the first two components represented 92.9% of the total variability in the total variation. AHC classified cultivars into four main groups on the basis of the measured parameters. Black coloured genotype was found to be rich source of phenols, flavonoids and anthocyanin with very high antioxidant activity. Orange cultivars were found to be rich sources for β-carotene compared to red & black cultivars.     

Anthocyanin and phenolic characterization,chemical composition and antioxidant activity of chagalapoli (Ardisia compressa K.) fruit: A tropical source of natural pigments

Chagalapoli (Ardisia compressa K.) is a tropical fruit of deep purple color with a high content of pigments. Anthocyanins, polyphenol composition, antioxidant activity and physicochemical characteristics of chagalapoli fruits (CF) are analyzed. The proximal and mineral composition is similar to that found in common berries (strawberry, blackberry and blueberry). A high content of total phenolics (1051.3 ± 43.5 mg of gallic acid equivalents/100 g of FW) is present, among which anthocyanins predominated (796.0 ± 2.3 mg of cyanidin 3-O-glucoside equivalents/100 g FW). Twelve anthocyanins were separated and ten of them identified by HPLC–DAD–MS. The main anthocyanins were malvidin-3-O-galactoside (35%), delphinidin 3-O-galactoside (28%) and petunidin 3-O-galactoside (19%). Other polyphenols identified included: flavonols, flavan-3-ols (catechin and proantocyanidin dimers) and hydroxycinnamoyl derivatives. The antioxidant activity of CF was 40% higher than that found in common berries, which were simultaneously analyzed. The high content of anthocyanins in CF and its peculiar anthocyanin profile make this under-utilized fruit a promising source of pigments and phenolic nutraceuticals.     

Chemical composition of wild edible mushrooms and antioxidant properties of their water soluble polysaccharidic and ethanolic fractions

Mushrooms have become attractive as functional foods and as a source of physiologically beneficial bioactive compounds. Herein, we describe and compare the chemical constituents (phenolic compounds, macronutrients, sugars, fatty acids, tocopherols and ascorbic acid) of four wild edible mushrooms widely appreciated in gastronomy: Armillaria mellea (Vahl) P. Kumm., Calocybe gambosa (Fr.) Donk, Clitocybe odora (Fr.) P. Kumm., Coprinus comatus (O.F. Müll.) Pers. Furthermore, the antioxidant activity of their water soluble polysaccharidic and ethanolic fractions was studied by three different in vitro assays. C. comatus revealed the highest concentrations of sugars (43.23/100 g dry weight), PUFA (77.46%), phenolic compounds (45.02 mg/kg), tocopherols (301.03 μg/100 g) and, among all of the fractions tested, its ethanolic fraction showed the highest antioxidant activity (EC₅₀ < 2.6 mg/ml). C. odora revealed one of the highest ascorbic acid (172.65 mg/100 g) contents and its water soluble polysaccharidic fraction showed the best antioxidant properties (EC₅₀ < 3.6 mg/ml) among the polysaccharidic fractions. The studied mushrooms species could potentially be used in well-balanced diets and as a source of bioactive compounds.     

Effect of storage on antioxidant activity of freeze-dried potato peels

A study was undertaken with the objective of evaluating the storage stability of the polyphenols and the antioxidant activity in the peel from two varieties of potatoes, Penta and Marcy, grown in Ontario, Canada. Samples were stored at ?20, 4 and 25 °C for 0, 2, 4 and 8 weeks. Peel from Penta variety contained higher levels of total polyphenolic compounds, 2.4 mg/g of peel d.w. compare to Marcy, 1.14 mg/g of peel d.w. Chlorogenic and caffeic acids were the major polyphenolic compounds present in both verities. Levels of polyphenolic compounds in the peel were influenced by storage temperature with maximum loss observed at 25 °C. Storage time caused a decline in the levels of polyphenolic compounds up to 4 weeks at all temperatures followed by a significant increase at the end of week 8. There was a parallel increase in the antioxidant activity of the peel samples during storage and until the end of 8 weeks of storage. At all temperatures of storage, there was a significant relationship (r = 0.43, P ≤ 0.05) between the amount of polyphenolic compound in the peel samples and their antioxidant capacity. Results suggest potato peel as a valuable source of polyphenolic compounds requiring proper storage condition to maintain their antioxidant properties.     

Optimization of solid–liquid extraction of phytochemicals from Garcinia indica Choisy by response surface methodology

A central composite rotatable design was employed to study the effect of ultrasound assisted extraction conditions namely sonication amplitude (10–90%), sonication cycle (0.1–1.0 s^?1), solid–liquid ratio (2–10) and extraction time (5–35 min) on the total anthocyanin extraction from Garcinia indica Choisy. Overall extractions of total anthocyanin, acidity and antioxidant activity were considered as response variables. The significant (p < 0.05) response surface models with high coefficients of determination values (R²) ranging from 0.91 to 0.93 were fitted for the experimental data, which indicated that the polynomial response models fitted well for describing the extraction efficiencies of anthocyanin, acidity and antioxidant activity. Based on the design, the optimal conditions for obtaining higher extraction were extraction time 35 min, cycle ranging from 0.44 to 0.48 s^?1, percentage amplitude ranging from 10 to 14%, and solid–liquid ratio 10. The graphical optimization of superimposed contour plots fulfilled the conditions to obtain total anthocyanin (Y₁) ≥ 135 mg/100 g DW, total titratable acidity (Y₂) ≤ 25 g/100 g DW and antioxidant activity (Y₃) ≥ 14.5 M Trolox/100 g DW. The study demonstrated that response surface methodology can be utilized for deriving the optimum conditions for extraction of anthocyanin from G. indica Choisy.     

Bean cultivars (Phaseolus vulgaris L.) have similar high antioxidant capacity,in vitro inhibition of α-amylase and α-glucosidase while diverse phenolic composition and concentration

Common beans are a good source of essential nutrients such as protein, fiber, vitamins, and minerals; they also contain phenolic compounds and other phytochemicals. Phenolic compounds exhibit high antioxidant capacity that promotes health benefits by reducing oxidative stress. The objective was to compare the composition and quantity of anthocyanins and other non-colored phenolic compounds in fifteen improved bean cultivars from Mexico and Brazil and their relation to antioxidant capacity and enzymes related to type-2 diabetes. Samples were analyzed for total phenolic compounds (TP), flavonoids, antioxidant capacity (AC), tannins and total anthocyanins. Type and quantity were evaluated by HPLC-ESI-MS. Delphinidin glucoside (0.9–129.0 mg/100 g dry coat), petunidin glucoside (0.7–115.0 mg/100 g dry coat) and malvidin glucoside (0.14–52.0 mg/100 g dry coat). Anthocyanidins were positively correlated when quantified by HPLC and colorimetric analysis (R = 0.99). Cultivar Negro-Otomi presented the highest concentration of anthocyanins (250 mg/100 g dry coat). Seventeen non-colored phenolic compounds were identified among cultivars; catechin, myricetin 3-O-arabinoside, epicatechin, vanillic acid, syringic acid and o-coumaric acid, presented the highest concentrations among identified phenolic compounds. The AC of all fifteen bean cultivars did not show significant differences (p > 0.05) ranging from 185.2 (FM-67) to 233.9 (FM-199) mmol TE/g coat. Compounds in the coat extracts of pinto and black cultivars were the most efficient to inhibit α-amylase and α-glucosidase. Studied cultivars differed in composition and concentration of phenolics including anthocyanins; however, there was no effect on AC as measured by oxygen radical absorbance capacity. Black beans contained delphinidin and ferulic acid, compounds commonly used as ingredients in functional foods due to their associated health benefits.     

The phenolic compounds and the antioxidant potential of infusion of herbs from the Brazilian Amazonian region

The consumption of tea increased significantly in the past few years as a result of its health benefits as potent antioxidants in the diet. However, studies on the antioxidant compounds from Brazilian tea are scarce. Thus, the aim of this work was to evaluate the total phenolic compounds (TPC) and total flavonoids (TF) contents and the antioxidant capacity (DPPH and β-carotene/linoleic acid system) of nine herb infusions from the Amazonian region, namely agirú (Chrysobalanus icaco), açoita-cavalo (Luehea speciosa), capim-santo (Cymbopogon citratus), erva-cidreira (Lippia alba), graviola (Annona muricata L.), jucá (Libidibia ferrea), pata-de-vaca (Bauhinia ungulata), parirí (Fridericia chica) and sacaca comum (Croton spp.). These herbs were chosen based on popular knowledge and consumption. C. ferrea (68.13 mg GAE/g), L. speciosa (47.54 mg GAE/g) and C. icaco (51.30 mg GAE/g) presented the highest TPC contents, while L. speciosa (12.85 mg CE/g) and L. alba (15.42 mg CE/g) showed the highest TF contents. The highest antioxidant capacity, using both assays, was shown by L. ferrea. The three herbs with the highest TPC contents were selected to be analyzed by high performance liquid chromatography (HPLC) coupled to a diode array detector (DAD). A commercial green tea (Camellia sinensis) was also analyzed as a reference. The main compounds tentatively identified were gallic acid (0.45 mg/g), myricetin (0.78 mg/g) and quercetin (0.14 mg/g) in C. icaco; (+)-catechin (1.20 mg/g) and quercetin (0.14 mg/g) in L. speciosa; gallic acid (0.59 mg/g) and quercetin (0.13 mg/g) in C. ferrea; and gallic acid (0.24 mg/g), (−)-epicatechin (2.44 mg/g), (+)-catechin (0.68 mg/g) and quercetin (0.66 mg/g) in green tea. Among the nine studied herbs, the importance of L. ferrea should be pointed out since it presented the highest TPC content and antioxidant capacity and its gallic acid content was much higher than that of green tea.     

Seed oils of ten traditional Portuguese grape varieties with interesting chemical and antioxidant properties

To increase the potential and better exploring of grape seeds that are an important wine-industrial waste, oils of ten traditional Portuguese grape varieties were evaluated in relation to their vitamin E content (tocopherols and tocotrienols), fatty acid profile, as well as, antioxidant properties. Our results showed that the grape-seed oils were a good source of γ-tocotrienol (499–1575 mg/kg), α-tocopherol (85.5–244 mg/kg) and α-tocotrienol (69–319 mg/kg). Concerning fatty acid profile, linoleic (C18:2cc), oleic (C18:1), palmitic (C16:0) and stearic (C18:0) acids were the predominant. Grape-seed oils demonstrated to be a good source of polyunsaturated fatty acids (PUFAs) (63.64–73.53%), whereas monounsaturated fatty acid (MUFA) and saturated fatty acid (SFA) ranged between 14.19–21.29% and 11.64–14.94%, respectively. Interesting values of DPPH and ABTS radical scavenging activities were also obtained. This study demonstrated that these seeds may be reused and their oils incorporated in other food products, taking into account the compounds with positive effects on human health that are present in their composition.     

Phenolic profile and antioxidant activity of the Algerian ripe date palm fruit (Phoenix dactylifera)

The aim of this study was to determine the phenolic profile of seven different varieties of ripe date palm fruit (Phoenix dactylifera) from Algeria by LC–DAD–MS (ESI+), to investigate their respective antioxidant activities by the DPPH^· method and to estimate their phenolic content using the Folin–Ciocalteu method. The total phenolic content was in the range of 2.49 ± 0.01 to 8.36 ± 0.60 mg gallic acid equivalents (GAE) per 100 g fresh fruit. This fruit was shown to possess an antioxidant activity, giving values of antiradical efficient (AE) from 0.08 ± 0.00 to 0.22 ± 0.00. The phenolic contents and the antiradical efficiencies of the different varieties were highly correlated (R²=0.975). All the varieties were found to contain mainly p-coumaric, ferulic and sinapic acids and some cinnamic acid derivatives. Three different isomers of 5-o-caffeoylshikimic acid were detected. Different types of flavonoids were identified, mainly flavones, flavanones and flavonol glycosides.     

Pinto bean hull extract supplementation favorably affects markers of bone metabolism and bone structure in mice

Hulls from dry edible beans are rich in phenolic compounds recognized as possessing antioxidant activity. The aim of this study was to characterize antioxidant properties of bean hull extract (BHE) and to determine whether BHE supplementation (at 400 or 800 mg/kg for 3 months) affects serum biochemical markers and bone structure in 12-month-old male C57BL/6 mice. Mice supplemented with 800 mg BHE/kg had lower serum tartrate-resistant acid phosphatase and parathyroid hormone concentrations than those on control diet or supplemented with 400 mg BHE/kg. BHE supplementation caused slight decrease in oxidized glutathione concentration in blood (P = 0.07). Compared to the control group, BHE supplementation at 800 mg/kg for 3 months improved bone structural indices, bone mineral density and trabecular thickness in the third lumbar vertebra. These results suggest that BHE supplementation may have beneficial effects on bone health in mice by decreasing bone resorption.     

Phytochemical,antioxidant and pigment stability of açai (Euterpe oleracea Mart.) as affected by clarification,ascorbic acid fortification and storage

Açai juice at two clarity stages (semi-clarified and clarified) was compared to 100% açai pulp following ascorbic acid fortification to evaluate phytochemical and antioxidant changes during storage at 4 and 20 °C. Cyanidin-3-rutinoside (202 ± 5.8 mg/L) and cyanidin-3-glucoside (75 ± 4.8 mg/L) were the predominant anthocyanins in açai while 11 non-anthocyanin polyphenolics were detected in concentrations from 1.1 to 55 mg/L of açai pulp. Clarification of açai pulp resulted in a 27% loss in total polyphenolics (197 ± 6.9 mg gallic acid/100 mL) and in a 20% reduction in both total anthocyanins (729 ± 3.4 mg/L) and antioxidant capacity (54 ± 1.7 μmol Trolox equivalents/mL). Anthocyanin degradation followed first order kinetics, with half-lives ranging from 9.4 to 43 days for cyanidin-3-glucoside and from 18 to 82 days for cyanidin-3-rutinoside. Fortification with ascorbic acid accelerated anthocyanin degradation in clarified juice at both storage temperatures, likely due to the loss of polymeric anthocyanin forms (21%) during clarification. Although clarification enhanced the amount of monomeric anthocyanins present in açai juice which relates positively to the aesthetic quality, processing and handling regimes must be optimized to achieve maximum retention of their functional properties during storage.     

Anti-inflammatory and antioxidant activities of red pepper (Capsicum annuum L.) stalk extracts: Comparison of pericarp and placenta extracts

Red pepper stalks, an agricultural waste product, are casually discarded at landfills where they oxidize and harm the local ecology. To our knowledge, no feasible method has been designed to evaluate the bioavailability of red pepper stalks. Therefore, the present study focused on the stalk waste investigating its superoxide dismutase (SOD) activity and inhibitory effect on nitric oxide (NO) production in macrophages. Interestingly, by comparison with red pepper pericarp and placenta extracts, the stalks were found to have higher phenolic, flavonoid, and capsaicin contents. Chromatographic data showed differences in the amounts of phenolic compounds in various parts of red pepper. At a concentration of 100 μg/mL, the stalk, placenta, and pericarp had SOD activities of 52.3%, 7.4%, and 10.4%, respectively. A very high level of chlorogenic acid (3.82 mg/g d w) and p-coumaric acid (2.98 mg/g d w) gave the stalks of red peppers the most powerful antioxidant activity among the three tested parts. The high phenolic and SOD activity-containing stalks also had the most significant NO inhibitory effect (53.5%) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. These results demonstrated that there is an opportunity to develop a new anti-inflammatory agent from agricultural wastes.     

Antioxidant activity of peanut seed testa and its antioxidative component,ethyl protocatechuate

The antioxidant activity of ethanolic extracts of peanut seed testa (EEPST) and its antioxidative component, ethyl protocatechuate (EP), was examined. It was found that EEPST and EP showed a dose-dependent activity on the inhibition of liposome peroxidation. EEPST and EP in the range of 50–500 mg/l were effective in protecting protein against oxidative damage. EEPST and EP at 100 mg/l showed 92.6% and 84.6% scavenging effect, respectively, on α,α-diphenyl-β-picrylhydrazyl radical, indicating that they act as a primary antioxidant. In addition, EEPST and EP, at a dose of 200 mg/l, showed 70.6% and 67.7% scavenging effect, respectively, on the hydroxyl radical. EEPST also exhibited a metal-binding ability, while EP did not. The inhibitory effect of EEPST on linoleic peroxidation correlated with their polyphenolic content. These results suggest that the antioxidant mechanism, for both EEPST and EP, could possibly be due to their scavenging effect on free radical and hydroxyl radical. In addition, its metal binding ability may contribute to antioxidant activity of EEPST.     

Characterization of the antioxidant functions of flavonoids and proanthocyanidins in Mauritian black teas

Tea drinking is associated with an improved antioxidant status in vivo which may contribute to the lowering of the risk of certain types of cancer, coronary heart disease and stroke. The polyphenolic bioactive composition and the antioxidant properties of Mauritian commercial black and fresh tea leaves were evaluated. Hot water infusates contained high levels of total phenols, total proanthocyanidins and total flavonoids. The concentrations of individual compounds, (+)-catechin, (−)-epicatechin, (−)-epicatechin 3-gallate, epigallocatechin, (−)-epigallocatechin 3-gallate, gallic acid, and procyanidin dimers B1 and B2 were high. The ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays were used to assess the antioxidant potential of tea infusates with the following order of potency: Ouvagalia tea > Buccaneer’s choice > Black Label > Red Label > Extra > Corson > Chartreuse > La Flora > 3-Pavillons. Linear regression analyses indicated high correlation coefficient with total proanthocyanidin (TEAC r = 0.96 and FRAP r = 0.95) and total phenol contents (TEAC r = 0.90 and FRAP r = 0.92) in infusates. Catechins and gallic acid significantly contributed to the overall antioxidant capacity of black tea extracts. In general, the fresh tea leaves had high levels of total phenols, total flavonoids, total proanthocyanidin and exhibited greater antioxidant potentials when compared with black teas. Thus Mauritian black teas and fresh tea leaves can be rich sources of polyphenolic compounds and antioxidants, which may be highly relevant to the maintenance of normal health and disease management, an observation that has led to the commencement of a clinical trial study to assess cardiovascular health in Mauritius.     

Evaluating eggplant (Solanum melongena L) genotypes for bioactive properties: A chemometric approach

Thirty four genotypes of eggplant and its wild relatives were evaluated for their total phenolics, flavonoid content and antioxidant capacity. Free radical scavenging was evaluated using four in-vitro assays, viz. FRAP (Ferric reducing antioxidant power), CUPRAC (cupric reducing antioxidant capacity), TEAC (Trolox equivalent antioxidant capacity) and DPPH (2, 2-diphenylpicrylhydrazyl). Total phenolics in eggplant showed a wide variation, ranging from 22.62 to 234.46 mg gallic acid equivalents (GAE)/100 g fw (244.28 to 2990.64 mg GAE/100 g dw). With the exception of Solanum aethiopicum and its accessions (Ac-1, Ac-2 and Ac-3), all wild relatives had significantly (p < 0.05) higher total phenolics and flavonoid content than cultivated ones. Total antioxidant capacity (FRAP) in wild genotypes ranged from 1.13 to 8.04 μmol Trolox (TE)/g. The hierarchy in decreasing order was Solanum khasianum > Solanum torvum > Solanum sisymbriifolium > Solanum incanum > Solanum integrifolium > S. aethiopicum. The antioxidant capacity correlated high with total phenolics in all assays. In cultivated group, JBR-99 and RCMBL-3 possessed high antioxidant capacity than the rest. Principal component analysis (PCA) and Hierarchical cluster analysis (HCA) revealed distinct similarity between JBR-99 (green), S. sisymbriifolium, S. khasianum and S. torvum. Overall results indicate that the wild species of S. torvum, S. incanum and S. sisymbriifolium are potential candidates for improving the functional quality of cultivated eggplant.     

Inactivation of polyphenol oxidase in muscadine grape juice by dense phase-CO2 processing

The effect of dense phase-CO₂ processing (DP-CO₂) on polyphenol oxidase (PPO) activity, polyphenolic and antioxidant changes in muscadine grape juice under different processing pressures (27.6, 38.3, and 48.3 MPa) and CO₂ concentrations (0, 7.5, and 15%) were measured. Subsequently two DP-CO₂ conditions (48.3 MPa at 0 or 15% CO₂) were evaluated for polyphenolic and antioxidant changes during storage (4 °C, four weeks). Pressure alone was responsible for a 40% decrease in PPO activity that resulted in 16–40% polyphenolic and antioxidant losses. Increasing CO₂ from 0 to 7.5% was responsible for an additional 35% decrease in enzyme activity and a two-fold greater polyphenolic retention. However, insignificant changes in PPO activity or polyphenolic retention were observed when CO₂ was increased to 15%. During storage, juices with residual PPO activity following processing resulted in greater polyphenolic (8- to 10-fold) and antioxidant capacity (four-fold) degradation compared to control juices with no PPO activity. This study demonstrated that partial PPO inactivation can be obtained by DP-CO₂ and that CO₂ level was the primary variable influencing PPO activity and polyphenolics and antioxidant capacity retention in muscadine grape juice.     

Bioactive substance contents and antioxidant capacity of raw and blanched vegetables

Five commonly consumed vegetables in Malaysia namely, four-angled bean (Psophocarpus tetragonolobus D.C.), French bean (Phaseolus vulgaris L.), long bean (Vigna sesquipedalis L.), snow pea (Pisum sativum var. macrocarpon L.) and snap pea (Pisum sativum) were blanched in boiling water for 10 min. The contents of total phenolics, ascorbic acid and β-carotene, and the antioxidant capacity as typified by β-carotene and free radical scavenging activity (DPPH) assays were determined for the raw and blanched vegetables. The study revealed that blanching caused a significant (p < 0.05) increase in β-carotene content [fresh (389–539 µg/100 g), blanched (510–818 µg/100 g)], except in snow pea. Conversely, there was a significant (p < 0.05) decrease in ascorbic acid content [fresh (1.2–7.8 mg/100 g), blanched (0.67–3.8 mg/100 g)]. After blanching, the total phenolic content and antioxidant activity either decreased or increased depending on the type of vegetables. The total phenolic content was positively correlated with the antioxidant activity of the studied vegetables to some extent, but not with ascorbic acid or β-carotene.Industrial relevanceBeans (four-angled bean, French bean and long bean), and peas (snow and snap pea) are commonly consumed vegetables in Malaysia. However, the scientific information regarding blanching and its effect on the total phenolic content and antioxidant activities is very limited. This work showed that blanching caused an increase in the carotene, total phenolic content and antioxidant activities in some of the selected vegetables. This work is important since, consumption of raw vegetables does not have high nutritional qualities and antioxidant activities as shown in this work.     

Biopolymer nanoparticles as potential delivery systems for anthocyanins: Fabrication and properties

Biopolymer nanoparticles and microparticles may be used as delivery systems for bioactive compounds in food and pharmaceutical applications. In this study, biopolymer nanoparticles were assembled from whey protein isolate (WPI) and beet pectin (BP) using thermal processing and electrostatic complexation. This approach involved mixing the two biopolymers at pH 5.8, heating (90 °C, 5 min) to induce protein nanoparticle formation and then adjusting the solution to pH 4.0 to promote coating of the protein nanoparticles with pectin. This process led to the formation of relatively small anionic biopolymer nanoparticles (d < 200 nm) at pH 4. The biopolymer particles had a high negative charged from pH 8 to 4.0 but became less anionic at lower pH values. The mean particle diameter was relatively small (d < 200 nm) around pH 4.0 but increased appreciably at lower and higher pH due to particle flocculation. The biopolymer nanoparticles were loaded with an anthocyanin-rich extract. A higher loading efficiency was observed when anthocyanin was added before heating the WPI-BP solution (LE = 55%) rather than after (LE = 35%), which was attributed to increased protein–polyphenol interactions. The encapsulation of anthocyanins within biopolymer particles improved their heat stability. However, encapsulated anthocyanin had a lower antioxidant activity than non-encapsulated anthocyanin, which was attributed to the thermal processing step required during particle fabrication and the binding of anthocyanins to biopolymers within the nanoparticles. Color measurements indicated that the encapsulation of anthocyanin within biopolymer particles did not inhibit its degradation after ascorbic acid addition. Overall, our results show that the encapsulation of anthocyanins within the biopolymer particles fabricated in this study was not particularly effective at improving their antioxidant activity or color stability. Alternative strategies are therefore needed to encapsulate this important color and nutraceutical agent.