Phytochemicals and antioxidant activity of different fruit fractions (peel,pulp, aril and seed) of Thai gac (Momordica cochinchinensis Spreng)

Three fractions (peel, pulp and aril) of gac fruit (Momordica cochinchinensis Spreng) were investigated for their phytochemicals (lycopene, beta-carotene, lutein and phenolic compounds) and their antioxidant activity. The results showed that the aril had the highest contents for both lycopene and beta-carotene, whilst peel (yellow) contained the highest amount of lutein. Two major phenolic acid groups: hydroxybenzoic acids and hydroxycinnamic were identified and quantified. Gallic acid and p-hydroxybenzoic acid were found in all fractions. Ferulic acid and p-hydroxybenzoic acid were most evident in pulp. Myricetin was the only flavonoid found in all fractions. Apigenin was the most predominant flavonoid in pulp (red), whereas rutin and luteolin gave the highest content in aril. The extracts of different fractions exhibited different levels of antioxidant activity in the systems tested. The aril extract showed the highest FRAP value. The greatest antioxidant activities of peel and pulp extracts were at immature stage, whereas those in the seed extracts increased from mature stage to ripe stage. The contents of total phenolic and total flavonoid in peel and pulp decreased during the fruit development stage (immature > ripe fruit) and subsequently displayed lower antioxidant capacity, except for the seed.     

Anthocyanin stability studies in Tibouchina semidecandra L.

The effects of pH, storage period, temperature, light and dark conditions on the stability of anthocyanins extracted from Tibouchina semidecandra flowers of different developmental stages was evaluated. Fully formed but unopened flower bud had the highest amount of total anthocyanin extracted from fresh petals. The anthocyanin contents for all flower developmental stages were stable at pH 0.5–3.0 but the colour of the extracts faded at higher pH values. Degradation percentages of total anthocyanins in the extracts kept at 25 °C were 7–20% lower than that maintained at 31 °C. Extracts stored in darkness at 25 °C maintained their purple colour for 26 days while light exposure reduced it to an average of 10 days. The study shows that suitable storage condition for coloured anthocyanin pigments in extracted form is in acidic conditions in the dark. This implies the potential usage of coloured anthocyanins as natural food colourants and shelf life indicator for acidic foods.     

Carotenoids and antioxidant capacities from Canarium odontophyllum Miq. fruit

Carotenoids were isolated and identified from peel, pulp and seed fractions of Canarium odontophyllum Miq., and their antioxidant capacities were evaluated. all-trans-β-carotene was present in a large amount in peel (69.5 ± 1.0 mg/kg), followed by pulp (31.1 ± 0.76 mg/kg) and seed (15.1 ± 3.0 mg/kg). Additionally, 15-cis-β-carotene, 9-cis-β-carotene and 13-cis-β-carotenes were also major contributors to carotenoid contents in peel, pulp and seed fractions. Pulp exhibited excellent β-carotene bleaching activity, significantly higher than peel and seed; high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, whereas peel exhibited significantly higher scavenging activity of 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals. All the extracts exhibited good inhibitory effect against hydrogen peroxide-induced haemoglobin oxidation, ranging from 45.3 to 59.7%. This is the first report about carotenoids and antioxidant capacities from C. odontophyllum fruit, and indicates that this fruit can be explored and promoted as a potential source of natural antioxidants.     

Chemical stability of açai fruit (Euterpe oleracea Mart.) anthocyanins as influenced by naturally occurring and externally added polyphenolic cofactors in model systems

The influence of different classes of naturally occurring and externally added polyphenolic cofactors on the phytochemical and colour stability of anthocyanins in açai fruit (Euterpe oleracea) was investigated. Model systems were based on anthocyanin isolates from açai fruit, rich in cyanidin-3-rutinoside (311 ± 27 mg/l) and cyanidin-3-glucoside (208 ± 18 mg/l), and isolated groups of naturally occurring polyphenolic cofactors in açai fruit (phenolic acids, procyanidins, and flavone-C-glycosides, each adjusted to ∼50 mg/l). Anthocyanin degradation kinetics were assessed as a function of pH (3.0, 3.5, and 4.0) and storage temperature (5, 20 and 30 °C). During storage, anthocyanins experienced pH and temperature-dependent losses, and the half life cyanidin-3-rutinoside (t_1/2 = 2.67–210 days) was consistently longer than cyanidin-3-glucoside (t_1/2 = 1.13–144 days). The presence of flavone-C-glycosides induced significant hyperchromic shifts and enhanced anthocyanin stability at all pH and temperature combinations, while no significant effects were attributed to the presence of phenolic acids or procyanidins. Additional models using externally added cofactors from rooibos tea, also rich in flavone-C-glycosides, resulted in up to 45.5% higher anthocyanin colour and up to 40.7% increased anthocyanin stability compared to uncopigmented anthocyanin isolates and had similar copigmentation effects to a commercial rosemary-based colour enhancer. Results suggest flavone-C-glycosides offer potential for their use as colour enhancers and stabilizing agents in products rich in cyanidin glycosides, particularly açai fruit-containing foods, juice blends, and beverages.     

Antioxidant activities of five different mulberry cultivars in Korea

Five major mulberry [Pachungsipyung (M-1), Whazosipmunja (M-2), Suwonnosang (M-3), Jasan (M-4) and Mocksang (M-5)] cultivated in Korea were assessed for their polyphenolic composition using spectrophotometric methodology, and tested for antioxidant potential by some different assays. The total polyphenol (TP) was found from 2235 to 2570 μg/g gallic acid equivalents, total anthocyanin (TA) content to vary from 1229 to 2057 μg/g, coloured anthocyanins (CA) from 126 to 190 μg/g, and total flavanol (TF) from 16.4 to 65.4 μg/g catechin equivalents except Mocksang (M-5). The ethanolic extract from mulberry fruit shows a rapid and concentration-dependent increase of antioxidant activity. Especially, the antioxidant activities of M-2 and M-4 are higher than those of the others in a hemoglobin-induced linoleic acid system. The reducing power compared with BHT was observed to high value in M-2, M-3 and M-4 extracts. Effectiveness in reducing powers was in a descending order of M-4>M-2>M-3>M-1>M-1. The DPPH-scavenging ability of the ethanolic extract from mulberry fruit was 60.0% at 200 and 212 μg of M-2 and M-4, respectively. M-2 and M-4 also showed sharply increase of hydroxyl scavenging ability with concentration of the extracts. IC₅₀ values in scavenging abilities on hydroxyl radicals were 30 mg and in a descending order of M-5>M-3>M-1>M-4>M-2. Superoxide anion-sacavenging activities of M-2, M-3 and M-4 showed 17.1, 14.5 and 14.8 SOD unit/mg, respectively.     

Changes in anthocyanins in arils of chitosan-coated pomegranate (Punica granatum L. cv. Rabbab-e-Neyriz) fruit during cold storage

Edible coatings as chitosan treatments (0%, 1% and 2%) were applied to ‘Rabbab-e-Neyriz’ pomegranate (Punica granatum L.). The effect of chitosan coating on individual anthocyanins and colour parameters of the juice during storage at 2 °C or 5 °C was examined. Six predominant anthocyanins were identified in the juice, with up to 935 mg/L total anthocyanins at the time of harvest. Cyanidin 3,5-diglucoside (402 mg/L) was the major pigment. The total anthocyanin content and chroma decreased with storage time in all applied treatments, although lightness and hue angle increased. These changes were reduced with chitosan treatments and at lower storage temperature (2 °C as compared to 5 °C). Based on the obtained results, the diglucoside anthocyanins were more stable than the monoglucosides. Chitosan coating followed by cold storage delayed anthocyanin degradation and prevented colour deterioration in the pomegranate arils.     

Bioactive compounds and antioxidant potential of mango peel extract

Bioactive compounds such as polyphenols, carotenoids and anthocyanins present in fruits and vegetables are receiving increased attention because of their potential antioxidant activity. Consumption of such antioxidants offers health benefits including protection against cardiovascular diseases and cancer. Mango peel is a major byproduct obtained during the processing of mango products such as mango pulp and amchur. In the present study, the antioxidant activity of mango peel extracts was examined. Polyphenol, anthocyanin and carotenoid contents in acetone extract of peels were determined. Ripe peels contained higher amount of anthocyanins and carotenoids compared to raw peels while raw mango peel had high polyphenol content. Antioxidant activity of ripe and raw mango peels extracted in acetone was determined using different antioxidant systems such as reducing power activity, DPPH free radical scavenging activity, iron induced lipid peroxidation of liver microsomes and soybean lipoxygenase inhibition. The IC₅₀ values were found to be in the range of 1.39–5.24 μg of gallic acid equivalents. Thus, the mango peel extract exhibited good antioxidant activity in different systems and thus may be used in nutraceutical and functional foods.     

Chemical and economic evaluation of natural antioxidant extracts obtained by ultrasound-assisted and agitated bed extraction from jussara pulp (Euterpe edulis)

This work aimed to evaluate the influence of ultrasonic and agitated bed extractions on the chemical composition and manufacturing costs of extracts obtained from jussara (Euterpe edulis) pulp. The effects of extraction time (5–180 min), temperature (25–55 °C), ethanol concentration (0–90% in acidified water) and solvent/pulp ratio (5–30 mL/g) on the extraction yield, phenolic content, anthocyanin content, antioxidant capacity and manufacturing costs were assessed. The yields provided by the ultrasound-assisted and agitated bed extractions were not significantly different. The anthocyanins and phenolic compound yields were significantly affected by the extraction time, the ethanol concentration in water and the solvent/feed ratio, but not by the temperature. In general, the antioxidant capacity of the extracts displayed tendencies similar to the anthocyanin and phenolic compound yields. The production of crude extracts obtained by ultrasound and agitated bed extraction incurred greater manufacturing costs compared to the market prices of assai extracts.     

Characterization of Anthocyanins in Fruit of Kadsura coccinea (Lem.) A.C. Smith by UPLC/Q-TOF-MS Analysis and Evaluation of Stability of the Major Anthocyanins

Anthocyanins in fruit of Kadsura coccinea (Lem.) A.C. Smith were identified by ultra-performance liquid chromatography–quadrupole–time of flight mass spectrometry analysis. Contents of anthocyanins in K. coccinea fruit were determined by HPLC analysis. Colour stability, thermal degradation and antioxidant activity of purified cyanidin-3-xylosylrutinoside were further analysed. As a result, four anthocyanins were identified as delphinidin-3-xylosylrutinoside (1), cyanidin-3-glucosylrutinoside (2), cyanidin-3-xylosylrutinoside (3), and cyanidin-3-rutinoside (4). The individual content of anthocyanins identified was 4.36?±?0.06, 3.01?±?0.03, 49.92?±?0.76 and 2.33?±?0.04 mg/500 g deseeded K. coccinea fruit, respectively. Cyanidin-3-xylosylrutinoside was stable at pH around 1. Moreover, cyanidin-3-xylosylrutinoside was very sensitive to temperature change and it was even unstable at room temperature. Cyanidin-3-xylosylrutinoside tended to degrade into cyanidin-3-rutinoside, cyanidin-sambubioside and cyanidin at high temperatures. Cyanidin-3-xylosylrutinoside exhibited much better 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical scavenging activities than those of butylated hydroxytoluene. However, cyanidin-3-xylosylrutinoside and other three anthocyanin components contributed little to the antioxidant activity of K. coccinea fruit.     

Antioxidant potentials of buntan pumelo (Citrus grandis Osbeck) and its ethanolic and acetified fermentation products

The antioxidant potentials of buntan pumelo (Citrus grandis Osbeck) and its fermented products were determined. The essential oil from peel had higher total phenolic (214 mM) and flavonoid (134 mg QE/g of dried material) contents than those of different solvent extracts from fruit pulp. In addition, DPPH free radical-scavenging activity and ferric-reducing antioxidant power values determined for the essential oil were 26.1 ± 1.2% and 2.3 ± 0.3 mM, respectively, which were significantly higher than those of various fruit pulp extracts. The ethanol-fermented products of pumelo juice had higher total phenolic and flavonoid contents than those of fresh juice. For maintenance of the substantial antioxidant properties of pumelo products, ethanol-fermented juice rather than fresh or acetate-fermented juice is recommended. Through correlation analysis, the phenolic compounds in the fermented pumelo products were found to be the major contributors to the free radical-scavenging activity and ferric-reducing power.     

Effect of low temperature storage on physical and physiological characteristics of eggplant fruit (Solanum melongena L.)

Eggplant (Solanum melongena L.) is a perishable and chilling-sensitive tropical fruit. The chilling injury (CI) symptoms as well as some physical and physiological implications were studied in eggplants Money Maker No. 2 stored at 0 and 10 °C for 15 days. Eggplants stored at 10 °C were not damaged by temperature, whereas fruit stored at 0 °C suffered CI. Eggplant stored at 0 °C exhibited a decrease in L₀ (lightness) and ΔL (oxidation potential), increase of pH and electrolyte leakage after CI symptoms are manifested. At this temperature, flesh tissue revealed ultrastructural damage. On the other hand, skin from upper fruit section showed more lightness, reddish colouration, and lower content of anthocyanins than the central fruit section at harvest and over the entire storage period at 0 °C. In fruit stored at this temperature and in upper section, changes of anthocyanin content with time were closely proportional to the Chroma evolution (lower content of anthocyanin, lower saturation of colour).     

Phytochemicals and antioxidant activity of different parts of bambangan (Mangifera pajang) and tarap (Artocarpus odoratissimus)

Mangifera pajang (family: Anacardiaceae; local name: bambangan) and Artocarpus odoratissimus (familiy: Moraceae; local name: tarap) are popular edible fruits in Sabah, Malaysia. The flesh, kernel and peel from M. pajang; seed and flesh from A. odoratissimus were analysed for total antioxidant activity, total polyphenol, total flavonoid and total anthocyanins contents. M. pajang kernel extract displayed the highest free radical scavenging and ferric reducing activities. Total phenolic content of the samples were in the range of 5.96–103.3 mg gallic acid equivalent/g. M. pajang kernel and M. pajang flesh contained the highest and lowest total flavonoid content with the values of 10.98 and 0.07 mg rutin equivalent/g, respectively. The antioxidant activities of extracts were significantly correlated with the total phenolic and flavonoid content (but not the anthocyanins content). The phytochemicals and antioxidant properties of M. pajang and A. odoratissimus, especially their by-products (kernel/seed), indicate that they may impart health benefits when consumed and should be regarded as a valuable source of antioxidant-rich nutraceuticals.     

Effects of nitric oxide fumigation on phenolic metabolism of postharvest Chinese winter jujube (Zizyphus jujuba Mill. cv. Dongzao) in relation to fruit quality

The effect of nitric oxide fumigation on phenolic metabolism of harvested Chinese winter jujube in relation to the fruit quality was investigated. The fruits were fumigated for 3 h with NO (0, 10, 20 and 30 μl/l) then stored at 22 °C and RH 95%. Changes in color, phenol and anthocyanin levels in pericarp, activities of the related enzymes, and total soluble solids and vitamin C from mesocarp were measured. The results showed that treatment with 20 μl/l NO significantly slowed the increase in red index, inhibited changes of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) activities, maintained a low total anthocyanin content and a high total phenol content, and delayed the increase of soluble solids and decrease of vitamin C. Treatment with NO solution at less than 1 μmol/l exhibited inhibitory effects on in vitro PPO and PAL activities in a dose-dependent manner.     

Change in anthocyanin concentrations in red apricot fruits during ripening

Here we report on accumulation patterns of anthocyanins and of β-carotene during fruit maturation, between 82 and 125 days after flowering, of two apricot (Prunus armeniaca L.) cultivars, A3576 and A3751. Both cultivars displayed an intense red colour of the skin but differed in their genetic background. The pigments were extracted from skin and flesh, separately, and analysed using HPLC-DAD-MS. Out of three anthocyanins detected here, the major compound, cyanidin-3-O-rutinoside was present at 75%. The two minor compounds were cyanidin-3-O-glucoside and peonidin-3-O-rutinoside. This is the first time that peonidin-3-O-rutinoside has been detected in apricot fruit. During maturation, A3751 accumulated anthocyanins in both skin and flesh, whereas anthocyanins were present only in the skin of A3576. The skin anthocyanin content was higher in A3751 (296 mg kg⁻¹) than in A3576 (41 mg kg⁻¹). Maximum anthocyanin levels were attained after 108 and 118 days of flowering in A3751 and A3576, respectively, in conjunction with loss of firmness and red colour acquisition on the un-blushed side of the fruit. At the end of ripening, the β-carotene flesh concentration reached 5 mg kg⁻¹ in A3576 and 15 mg kg⁻¹ in A3751. A significant effect of environment was observed on the anthocyanin content in the two cultivars.     

Nutritional constituents and antioxidant properties of indigenous kembayau (Dacryodes rostrata (Blume) H. J. Lam) fruits

The nutritional and antioxidant properties of peels, pulp and seeds of kembayau (Dacryodes rostrata) fruits were evaluated. Kembayau seeds and pulp were rich in fat, while peels had the highest ash contents. Potassium was the most prevalent mineral in peels (380.72-1112.00 mg/100 g). In kembayau fruits, total flavonoid content (1012.74-28,022.28 mg rutin equivalent/100 g) was higher than total phenolic and total monomeric anthocyanin contents. Kembayau seeds exhibited high flavonoid and phenolic contents compared to the contents in peels and pulp. Antioxidant capacities were also higher in seeds as typified by trolox equivalent antioxidant capacity assay (51.39-74.59 mmol TE/100 g), ferric reducing antioxidant power assay (530.05-556.98 mmol Fe²⁺/100 g) and by 1,1-diphenyl-2-picryl hydrazyl radical scavenging activity (92.18-92.19%) when compared to peels and pulp. Pulp and peels of kembayau fruit may be an important source of energy and minerals for human consumption, while seeds have a good potential as antioxidants.     

Anthocyanins composition and antioxidant activity of two major wild Nitraria tangutorun Bobr. variations from Qinghai-Tibet Plateau

Nitraria tangutorun Bobr., a unique kind of fruit, widely spreads in the Qinghai-Tibet Plateau. In the present study, nine anthocyanins were identified in two variations (purple fruit and red fruit) of N. tangutorun by HPLC/DAD-ESI/MS. Cyanidin-3-O-(trans-p-coumaroyl)-diglucoside (215.76 ± 22.91 mg of Mv3G5G equivalent per 100 g of fresh weight) and pelargonidin-3-O-(p-coumaroyl)-diglucoside (5.13 ± 0.35 mg of Mv3G5G equivalent per 100 g of fresh weight) were the main anthocyanins in the purple and red fruits respectively. In addition, most of the anthocyanins were acylated by coumaric acid, and the rare anthocyanins that naturally presented a coumaric acid in both cis and trans configurations have been detected. Furthermore, the extract of the two variations showed significantly different antioxidant activity (p < 0.01) according to DPPH, ABTS and FRAP assay. Purple fruit possessed higher antioxidant activity than red fruit. There were significant correlations between antioxidant activity and both the total polyphenol content and anthocyanins content. This work is valuable for elucidation of anthocyanins composition in N. tangutorun and for further utilization as a functional food and medicine material.     

Electrochemical behaviour and antioxidant capacity of anthocyanins from Chilean red wine,grape and raspberry

The anthocyanin fractions were extracted from Cabernet Sauvignon red wine, skins of Vitis vinifera grapes and raspberry fruits (Rubus idaeus). In red wine extract, 16 anthocyanins were identified, malvidin-3-O-glucoside being the main anthocyanin, which comprised 53.6% of the total anthocyanin in grape extract. Raspberry extract contained mainly delphinidin-3-O-glucoside and cyanidin-3-O-glucoside. The antioxidant capacity of the extracts was assayed by electrochemical methods. Best resolution of the oxidation peaks for the extracts and diluted wine was obtained by pulse differential voltammetry. The wine diluted 20× presented values of P1 (443 mV) and P2 (676 mV) similar to those corresponding to wine extract, and to the anthocyanin malvidin-3-O-glucoside. The antioxidant capacity of anthocyanins in extracts of wine, grape skin and raspberry fruit was also determined by the Trolox equivalent antioxidant capacity (TEAC) method.     

Effect of extraction conditions on the quality characteristics of pectin from passion fruit peel (Passiflora edulis f. flavicarpa L.)

Passion fruit (Passiflora edulis f. flavicarpa L.) yellow variety is composed of 50-55 g peel per 100 g of fresh fruit which is discarded as waste during processing. Utilization of passion fruit peel for pectin extraction was studied. Passion fruit peel obtained after juice extraction was blanched in boiling water for 5 min, dehydrated in a cross flow hot air drier at 60 ± 1 °C to a moisture content of 4 g/100 g of dried peel. The dehydrated passion fruit peel was used for extraction experiments of pectin. The effect of pH, peel to extractant ratio, and number of extractions, extraction time and temperature on the yield and quality characteristics of pectin were investigated. The optimized conditions for extraction of pectin from passion fruit peel yielded 14.8 g/100 g of dried peel. Pectin extracted from the dried peels had a methoxyl content of 9.6 g/100 g, galacturonic acid content of 88.2 g/100 g and jelly grade of 200. Extraction of pectin from dried peels of passion fruit may be considered for effective utilization of passion fruit processing waste.     

Characterization of anthocyanins in Kenyan teas: Extraction and identification

Characterization and quantification of anthocyanins in selected tea cultivars processed into black (aerated) and green (unaerated) tea products was carried out in this study. The anthocyanins were extracted from tea products processed from a number of newly bred purple leaf coloured Kenyan tea cultivars (Camellia sinensis) using acidified methanol/HCl (99:1 v/v). Extracted anthocyanins were purified by C₁₈ solid phase extraction (SPE) catridges and characterised by HPLC-UV-Visible. They were identified according to their HPLC retention times, elution order and comparison with authentic standards that were available. Total monomeric anthocyanins were determined by the pH-differential method. Although the tea cultivars gave different yields of anthocyanins, the unaerated (green) teas had significantly (p ? 0.05) higher anthocyanin content than the aerated (black) teas. This was attributed to the degradation of anthocyanins by polyphenol oxidase products (catechin O-quinones) formed during the auto-oxidation (fermentation) process of black tea manufacture. Of the six most common natural anthocyanidins, five were identified in the purified extracts from purple leaf coloured tea, in both aerated (black) and unaerated (green) teas namely; delphinidin, cyanidin, pelargonidin, peonidin and malvidin. The most predominant anthocyanidin was malvidin in both tea products. In addition, two anthocyanins namely, cyanidin-3-O-galactoside and cyanidin-3-O-glucoside were also identified. Tea catechins were also identified in the tea products derived from the purple coloured tea cultivars namely, epigallocatechin (EGC), catechin (+C), epicatechin (EC), epigallocatechin gallate (EGCG), and epicatechin gallate (ECG). Correlation between the total catechins versus the total anthocyanins and anthocyanin concentration in unaerated teas revealed significant negative correlations (r = −0.723^∗ and r = −0.743^∗∗, p ? 0.05 and p ? 0.01, respectively). However, in aerated (black) tea the correlations were insignificant (r = −0.182 and r = −0.241, p > 0.05).     

Antioxidative and anti-inflammatory properties of Citrus sulcata extracts

Citrus sulcata was subjected to ultrasound, high-pressure, and Soxhlet extractions. The antioxidant and anti-inflammatory activities of the extracts were evaluated qualitatively and quantitatively. The antioxidant content of the peel extract was twice that of the fruit extract. The quantitative analysis showed that the narirutin and hesperidin contents in the peel extracts were 8.8 and 7.5 mg/100 g, respectively. These extracts had a total phenolic content of 112.22 ± 2.89 gallic acid equivalent (GAE) mg/100 g, a total flavonoid content of 54.09 ± 1.01 rutin equivalent (RE) mg/100 g, DPPH radical scavenging activity of 46%, and antioxidant activity of 213.25 ± 2.82 μM of Trolox equivalents (TEAC). C. sulcata extracts could prevent hydrogen peroxide (H₂O₂)-induced oxidative stress, reduce expression of the inflammatory markers nuclear Factor kappa B (NFκB) and phosphorylated IκBα (p-IκBα) in A549 human lung carcinoma cells, and inhibit Lipopolysaccharide (LPS)-induced THP-1 monocyte differentiation to an extent of 85%.