Phenolic profile and antioxidant capacities of dried red currant from Serbia, extracted with different solvent

The antioxidant capacity and the phenolic content of 3 dried red currant samples from different geographical regions were studied. Three solvent systems were used (methanol, ethanol, and acetone) at the same concentrations (70%) and with 100% deionized water in presence 0.1% HCl. The antioxidant capacity of the dried fruit extracts was evaluated using DPPH radical scavenging assays. The efficiency of the solvents used to extract phenols from the 3 dried red currant samples varied considerably. The polyphenol content of the dried red currant samples was 3.26 to 12.68 mg gallic acid equivalent/g dried fruit. The high phenolic content was significantly correlated with the high antioxidant capacity. The following compounds were identified and quantified using HPLC with photodiode-array detection: 3 anthocyanins, 2 flavonols, 2 flavan-3-ols, and 3 hydroxycinnamic acids in all samples. Generally, red currant fruits are a rich source of phenolics, which shows an evident antioxidant capacity.     

Phenolic contents,antioxidant activities and potential bioaccessibilities of industrial pomegranate nectar processing wastes

Antioxidant potential and bioaccessibility of co‐products from industrial pasteurised pomegranate nectar (PN) processing such as peel (PP), press cake (PC) and precipitate after clarification (PAC) in comparison with raw material (arils) and final products (CON and PN) were determined. Total phenolic (TPC), flavonoid (TFC), anthocyanin (TAC), tannin contents (TTC) and antioxidant activity (TAA) were determined besides identifying major phenolics and investigating in vitro bioaccessibility after gastrointestinal (GI) digestion. PP showed the highest values, except for TAC. Phenolics (12.7–43.0%) were found to be more stable than anthocyanins (0.6–2.1%) after in vitro GI digestion. PAC was found to be a better source for anthocyanins than CON and also showed higher phenolic bioaccessibility (28.8%) than PN (19.6%). PC and PAC possessed as much TPC, TFC, TTC and TAA levels as CON, with some exceptions. Therefore, these results indicated that not only PP but also PC and PAC should be valorised as a good source for phenolics and anthocyanins.     

Effect of in vitro‐simulated gastrointestinal digestion on the stability and antioxidant activity of blueberry polyphenols and their cellular antioxidant activity towards HepG2 cells

In this study we investigated the influence of in vitro‐simulated gastrointestinal digestion on the bioaccessibility and antioxidant activity of polyphenols from blueberries (Vaccinium spp.). Total phenolic, anthocyanin, and flavonoid content was determined, and extract and digesta compositions were analysed by HPLC‐ESI‐MS/MS. The phenolic compounds were relatively stable under a gastric environment, whereas polyphenols and anthocyanins were unstable under an intestinal environment. The bioaccessibility of polyphenol, anthocyanin, and flavonoid was greatly decreased after the intestinal digestion, and the recoveries were only 13.93%, 1.95%, and 15.68% (the IN sample), respectively. Polyphenolic profile alteration occurred during in vitro‐simulated gastrointestinal digestion. Changes of phenolic compound antioxidant activity during digestion correlated with polyphenol, flavonoid, and caffeic acid concentrations. Digested extract cellular antioxidant activity was lower than non‐digested extract activity (P < 0.05). Polyphenol dose–response correlations with cellular antioxidant activity were observed. These results indicated that in vitro‐simulated gastrointestinal digestion significantly impact polyphenols and their antioxidant activity.     

Stability and antioxidant activity of anthocyanins from purple sweet potato (Ipomoea batatas L. cultivar Eshu No. 8) subjected to simulated in vitro gastrointestinal digestion

The study was aimed to investigate the stability and antioxidant activities of anthocyanins obtained from purple sweet potato via an in vitro digestion system. Three fractions of anthocyanin-rich extracts were obtained via ODS packing column. Anthocyanins and copigment (primary phenolic acids) of fraction 2 were investigated during simulated an in vitro gastrointestinal digestion. Anthocyanins and copigment were recognised by UPLC-LTQ-MS/MS. Besides, anthocyanins were found effectively stable under the acidic gastric digestion conditions. However, the anthocyanins recovery was greatly decreased at around 10% after intestinal digestion. An association between the type, number of acylated group and stability to intestinal digestion was found. Di-acylated anthocyanins possessed higher stability compared with mono-acylated anthocyanins and the stability of acylated group in digestion process followed the order of p-hydroxybenzoyl > feruloyl > caffeoyl. However, there was no much difference in copigment content which was found during digestion process. Moreover, the radical scavenging ability and xanthine oxidase (XO) inhibition showed that the digestion products possessed good biological activities mainly due to its anthocyanin composition.     

Effects of gastrointestinal digestion models in vitro on phenolic compounds and antioxidant activity of juçara (Euterpe edulis)

This study evaluated the effects of different gastrointestinal digestion models in vitro on the bioaccessibility of phenolics and antioxidant activity in juçara frozen pulp. In the sequence, method 3 was applied to juçara fruit in three different stages of maturation (vitrin – reddish fruits, mature – purple fruits, tuíra – deep purple fruits). In the method applied, the final pH adopted was 5.0, in order to avoid interference in the assay used to determine the antioxidant activity, and BHT was used to prevent excessive oxidation in the system. In this method, higher values for antioxidant activity were obtained (3574.95–3719.10 μmol L^?1 Trolox 100 g^?1 pulp) compared with the other two methods tested (1969.14–3034.74 μmol L^?1 Trolox 100 g^?1 pulp). In relation to juçara fruit, the mature stage was found to be ideal for processing, showing generally higher values of the bioaccessibility for phenolics and antioxidant activity compared to other maturation stages.     

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.     

Effect of thermal processing and digestive protease on the antioxidant capacity of fruit juice–milk beverage model systems under simulated gastrointestinal digestion

The effects of thermal processing and digestive protease on the antioxidant capacity of fruit juice–milk beverage (FJMB) models containing whey protein (WP) and chlorogenic acid or catechin (CAT) under in vitro digestion were investigated. After gastric digestion, the FJMB showed a significant (P < 0.05) increase in ABTS, but little change in ferric reducing antioxidant power (FRAP). Intestinal digestion decreased the FRAP and increased ABTS except in the model containing 0.1% CAT. There were different effects (none, masking, synergistic effect) in the antioxidant activity of the WP and phenolics under digestion. Pasteurisation (63 °C/30 min) had no significant effect on the FJMB's antioxidant capacity, while sterilisation (121 °C/10 min) significantly (P < 0.05) increased, decreased or had no significant effect on ABTS and FRAP under digestion, depending on the model. Pepsin and pancreatin significantly (P < 0.05) decreased the fruit phenolics' ABTS. Ferric reducing antioxidant power was not significantly influenced by pepsin during gastric digestion, but was significantly (P < 0.05) decreased by pancreatin during intestinal digestion. These results would be helpful to improve the efficacy of fruit phenolics in FJMB subjected to thermal processing and to maintain the health benefits of this kind of functional products in the food industry.     

Jam Processing Effect on Phenolics and Antioxidant Capacity in Anthocyanin-rich Fruits: Cherry, Plum, and Raspberry

ABSTRACT: Four cultivars of sour cherries (Balaton, Karneol, Kroeker and Northstar), 2 cultivars of plums (BY 8158.50 and Methley), and 1 red raspberry cv. Prelude were analyzed for total phenolics, antioxidant capacity, and total anthocyanins before and after jam production to evaluate their changes after thermal processing. Fruits had total phenolics ranging from 245.7 to 398.5 mg gallic acid equivalent (GAE)/100 g. Antioxidant capacity of fruits ranged from 354.8 to 692.3 mg/100 g, expressed as vitamin C equivalent antioxidant capacity (VCEAC). Total anthocyanins of fruits ranged from 30.9 to 67.1 mg cyanidin 3-glucoside equivalent (CGE)/100 g. In 100 g of jam, total phenolics varied from 132.9 to 218.9 mg GAE, while antioxidant capacity ranged from 205.6 to 373.5 mg/100 g VCEAC. Jams had total anthocyanins of 5.4 to 30.4 mg CGE/100 g. On the basis of fresh fruit (100 g), the processing and heating during jam making generally decreased the contents of total phenolics, VCEAC, and total anthocyanins. Major losses occurred in anthocyanin content where overall retention varied from 89% to 21%. HPLC analysis of individual anthocyanins from cherry cv. Balaton to its jam showed that processing caused 90% decrease in anthocyanins. The results indicated that more than 73% total phenolics and more than 65% antioxidant capacity were retained after processing fruits into jams. Optimization of food processing would help to conserve the bioactive phenolic compounds in fruits.     

Effects of in vitro simulated digestion on the free and bound phenolic content and antioxidant activity of seven species of seaweeds

The effects of simulated gastrointestinal digestion on the content and antioxidant activity of phenolics of seven seaweeds were investigated: Two methods of digestion were used – simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) to mimic the stomach and upper intestinal environment. Results showed that SIF can significantly increase the free phenolic content of all tested seaweeds. The total phenolic content of the seaweeds increased in range from 4.16 to 17.24 mg GAE/g before simulated digestion to 4.08 to 40.37 mg GAE/g after digestion. The antioxidant activity of seaweed-bound phenolics was superior to that of free phenolics. Among the seven varieties of seaweeds, Sargassum thunbergii and Sargassum kjellmanianum contained the highest content of bound phenolics after SGF digestion. Bound phenolics of Undaria pinnatifida and Sargassum thunbergii showed the highest in vitro ABTS⁺ free radical scavenging ability, while Sargassum thunbergii and Sargassum fusiforme showed the highest in vitro FRAP antioxidant activity.     

Antioxidant capacity and related parameters of different fruit formulations

Fruits and vegetables are known as good sources of phytochemicals, essential to prevent degenerative diseases like cancer and cardiovascular diseases (CVD). They contain a variety of antioxidants, which are useful to scavenge radical oxygen species (ROS). Besides smoothies, fruit purees, concentrates and juices - used by the food industry for these new beverages - were analysed. Total phenolics by Folin-Ciocalteu method, vitamin C content and antioxidant capacity (AOC) by FRAP, TEAC and ORAC assay were analysed by using high-throughput methods on a microplate reader. Vitamin C content ranged from 31 ± 3 mg/100 g in drinkable pomegranate concentrate to 1373 ± 125 mg/100 g in acerola puree; total phenolics content was quantified between 51 ± 1 mg gallic acid equivalents (GAE)/100 g in the mango-peach smoothie and 1152 ± 62 mg/100 g in the ascorbic acid rich acerola puree. The AOC differed depending on kind of fruit and antioxidant assay used. In most fruit products the major portion of AOC was generated by polyphenolic compounds, except acerola puree and orange juice. Very good correlations between total phenolics content and antioxidant capacity were found in the single fruit products, however not in the fruit and vegetable smoothies. Most of the analysed smoothies were able to supply with one package nearly the recommended dietary intake (RDI) of vitamin C for adults of 100 mg per day.     

Exploring the effect of microwave treatment on phenolic flavonoids,antioxidant capacity,and phenolic in vitro bioaccessibility of sorghum

The effect of microwave treatment on phenolics, flavonoids, antioxidant capacity, and phenolic in vitro bioaccessibility of white and red sorghum was evaluated. After microwave treatment for 40 s, the contents of free, bound, and total phenolics in white and red sorghum increased by 15.6–42.6, 4.0–23.4, and 19.7–66.0 mg gallic acid equivalents 100 g⁻¹ dry weight (DW), respectively, and the contents of free, bound, and total flavonoids increased by 9.4–11.2, 4.8–5.4, and 14.2–16.6 mg rutin equivalents 100 g⁻¹ DW, respectively. With increasing microwave treatment time, the contents of phenolic acids and flavonoids in white and red sorghum first increased and then decreased. Additionally, the changes in antioxidant capacity indicated a similar trend with phenolic contents for white and red sorghum. In vitro gastrointestinal digestion indicated that microwave treatment had no effect on the phenolic bioaccessibility of white and red sorghum but increased the release amount of phenolic acid and antioxidant capacity.     

Solvent extraction and in vitro simulated gastrointestinal digestion of phenolic compounds from purple sweet potato

The total content of phenolic compounds in purple sweet potato (PSP) was determined and the release of such compounds from PSP in gastrointestinal digestion was studied in vitro. The extraction conditions for the maximum recovery of free phenol (FP) and bound phenol (BP) from PSP were determined by response surface methodology (RSM). The maximum recovery of FPPSP was 14.16 ± 0.87 mg GAE per g short for dry weight (DW), which was obtained using 60% (v/v) ethanol maceration with a liquid–solid ratio of 57.21:1 (mL g⁻¹) at 51.93 °C for 2.12 h. The maximum recovery for BPPSP was 7.54 mg GAE per g DW, which was obtained upon hydrolysis with 1.87 mol L⁻¹ NaOH at a liquid–solid ratio of 35.93:1 (mL g⁻¹) for 4.74 h. The maximum phenolic content was released after 1 and 2 h for the in vitro gastric and intestinal digestion respectively. The release of the phenolics was promoted by pepsin and gastric acid during gastric digestion, while it was further promoted by trypsin during intestinal digestion.     

Phenolics, betacyanins and antioxidant activity in Opuntia joconostle fruits

Sour prickly pears (xoconostles) are fruits from Opuntia joconostle cactus, which are cultivated in the central Mexico area. Phenolic and pigment content in various parts of O. joconostle fruits were analyzed. The antioxidant activity of a methanolic extraction and different semi-purified fractions were also evaluated by the DPPH⁺ method. Xoconostle fruits were obtained from a commercial orchard in Mexico State. Fruits were analyzed as whole fruit and each fruit part including pericarp, mesocarp and endocarp. Samples were homogenized and kept at 4 °C until sample preparation. Total phenolic content and total flavonoid content varied among the different parts of the fruit. The highest amount of phenolic compounds and total flavonoids content were found in pericarp 2.07 mg gallic acid equivalents (GAE)/g fresh weight (FW) and 0.46 mg(+)-catechin equivalents (CE)/g FW respectively. Seven phenolics were identified as protocatechuic, 4-hydroxybenzoic, caffeic, vanillic and syringic acids, rutin, and quercetin. The color of the fruit parts was mainly due to the presence of betacyanins. The betacyanin concentration was higher in the endocarp (23.03 mg betanin equivalents/100 g fresh weight) than in the pericarp and mesocarp. Betacyanins were identified by HPLC-PDA-MS as betanin, isobetanin, betanidin, isobetanidin, and phyllocactin. Methanolic extracts and semi-purified fractions A (phenolics and flavonols) and B (betacyanins) of xoconostle showed high antioxidant activity mainly in the pericarp. These results suggest that xoconostle is a rich source of antioxidant compounds such as phenolic compounds and betacyanins.     

野生蓝果忍冬多酚鉴定及其抗氧化、降血糖活性

目的：对野生蓝果忍冬进行多酚成分鉴定和抗氧化、抗淀粉酶活性研究。方法：以我国小兴安岭地区的野生蓝果忍冬果实为材料,通过固相萃取技术分离纯化得到花色苷和非花色苷分离液,测定分离液中的化学成分,并测定多酚粗提液中总酚和总花色苷含量,抗氧化活性（1,1-二苯基-2-三硝基苯肼自由基清除能力、铁离子还原能力、2,2’-联氮-双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力、氧自由基吸收能力）,抗α-淀粉酶、α-葡萄糖苷酶活性和脂肪酶活性。结果：野生蓝果忍冬果实中含有丰富的花色苷和非花色苷多酚,尤其是矢车菊素-3-葡萄糖苷和山柰酚-3-芸香糖苷含量很高;蓝果忍冬多酚粗提液中总酚含量为82.7 mg/100 g,总花色苷含量为49.8 mg/100 g,具有较强的抗氧化活性;对α-淀粉酶、α-葡萄糖苷酶活性的半抑制质量浓度分别为0.39 mg/mL和0.933 mg/mL,对脂肪酶活性的半抑制质量浓度为12.31 mg/mL,说明蓝果忍冬可以作为一种有前景的淀粉酶抑制剂。     

Effects of exogenous abscisic acid on phenolic characteristics of red <Emphasis Type="Italic">Vitis vinifera</Emphasis> grapes and wines

The effects of exogenous abscisic acid (ABA) on phenolic characteristics of grapes and wines were investigated in Vitis vinifera cvs. Merlot and Cabernet Sauvignon. Exogenous ABA treatment at veraison significantly improved phenolic contents, mainly anthocyanins and flavonols, and antioxidant properties of the grape skins, but had no effects on total phenolics and antioxidant activities in the seeds or on basic fruit qualities. The wines made from ABA-treated grapes were also consequently enhanced in total phenolics, anthocyanins, flavonols and antioxidant activities. The proportions of methylated anthocyanins in the skins and acylated anthocyanins and derived pigments in the wines were decreased to some degree by exogenous ABA treatment. No distinct relationships were observed between ABA concentrations and phenolic characteristics, and the effects were observed even with 200 mg/L ABA. The results revealed that exogenous ABA applied at veraison offered opportunities to improve phenolic contents and nutritional values of grape skins and wines.     

Antioxidant activity,phenolic and anthocyanin contents of various rhubarb (Rheum spp.) varieties

Antioxidant activity (ABTS assay), total phenolics and total anthocyanins were determined in the petioles of twenty‐nine rhubarb (Rheum spp.) varieties. Antioxidant activity ranged from 463 ± 50 (Rheum officinale) to 1242 ± 2 μmol Trolox per g DW (Valentine). The phenolic content varied from 673 ± 41 (Loher Blut) to 4173 ± 23 mg GAE/100 g DW (Plum Hutt) and had a low correlation (r = 0.663) with antioxidant results. Seven of the varieties (Plum Hutt, Valentine, Minnesota No. 8, Cherry Red, Cawood Delight, Coulter McDonald and OR 23) had higher total phenolics than kale, a vegetable rich in phenolics. The concentration of anthocyanins ranged from 19.8 ± 1.5 (Crimson Red) to 341.1 ± 41.6 mg/100 g DW (Valentine). The percentages of two main anthocyanins in rhubarb, cyanidin 3‐glucoside and cyanidin 3‐rutinoside varied from 66.07:33.93, respectively, in Valentine to 9.36:90.64, respectively, in R. officinale.     

The profile,content and antioxidant activity of anthocyanin in germinated naked barley grains with infrared and hot air drying

Anthocyanin-rich naked barley has attracted considerable attention recently. In this study, the naked barley was allowed to germinate and took samples every 12 h, and dried by infrared or hot air. A total of 11 anthocyanins were detected, and germination and drying did not cause their profile to change. The total content of anthocyanins increased after germination, and hot air drying (53.45–68.53 mg/100 g) was more reserved than infrared drying (46.44–55.46 mg/100 g). Moreover, the sprouting improved the ferric reducing antioxidant power and the free radical scavenging ability of ABTS, DPPH, hydroxyl and superoxide anion capacity, and the germinated for 24 h by hot air drying sample had the strongest antioxidant capacity. Meanwhile, the metabolic position of seven anthocyanins was accurately found in the anthocyanin metabolic pathway. This study provides a theoretical basis for germination and hot air drying to improve the bioactive components and antioxidant properties of naked barley.     

Effect of different freezing methods on the bioaccessibility of strawberry polyphenols

Freezing is one of the most well-established food preservation technique that is used to prolong the shelf life and maintain the quality of strawberries. The aim of the present study was (i) to investigate the changes in polyphenols from fresh and frozen strawberries during in vitro digestion and (ii) to compare effects induced by individual quick freezing (IQF) and conventional freezing (CF). Spectrophotometric methods were used to determine total phenolics, flavonoids, anthocyanins and antioxidant capacity, whereas identification and quantification of major polyphenols were carried out using UPLC-ESI-MS/MS and HPLC-PDA, respectively. The results showed that the bioaccessible amount of major anthocyanin from frozen strawberries, i.e., pelargonidin-3-glucoside, corresponding to 72–89% of the total anthocyanins, was significantly higher than that of fresh strawberries (10.8–13.3 and 5.8 μg g⁻¹ sample, respectively; P < 0.05). Overall, the current study highlighted that freezing, independent of process type, i.e., IQF or CF, enhances the total amount of bioaccessible anthocyanins in strawberries.     

Effects of Food Processing on Blueberry Antiproliferation and Antioxidant Activity

Cultivated highbush (Vaccinium corymbosum L.) and wild lowbush (Vaccinium angustifolium Ait.) blueberries are excellent sources of phytochemicals that are believed to have significant biological activity. The objective of this study was to determine whether incorporation of blueberries into food products affects their phenolic content or antioxidant and antiproliferation activity. Several blueberry fruit‐containing products including fresh, individually quick frozen (IQF), freeze‐dried, spray‐dried, heat‐dried, cooked, juice concentrate, pie filling, and jam were fractionated to remove sugars and isolate groups of phytochemicals based on solubility. The fractions were analyzed for total phenolics and assayed for ferric reducing antioxidant power (FRAP) antioxidant activity, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity, and hepa‐1c1c7 antiproliferative activities. For both cultivated and wild berries, fresh and IQF berries had the highest total phenols, antioxidant activity, and antiproliferation activity. Whole freeze‐dried wild blueberries also retained significant antiproliferative activity in 2 fractions eluted with acetone (fraction 4, 4% of control cell growth at 20 (μg/mL) and 50% aqueous acetone (fraction 5, 69% of control cell growth at 20 (μg/mL) and ranked close to the activities recorded for fresh (30% of control cell growth at 20 (μg/mL for fraction 5) and IQF whole fruit (27% of control cell growth at 20 (μg/mL for fraction 5). Products that were heat‐processed retained most of the antioxidant activity and total phenolics found in unprocessed whole fruit. However, the heat‐treated products lacked or had diminished antiproliferation activity, suggesting that although products may be high in phenolic compounds and antioxidant activity, some forms of bioactivity may be compromised by harsh processing methods.     

Effects of spirulina biomass on the technological and nutritional quality of bread wheat pasta

The objective of this study was to evaluate the effect of the incorporation of spirulina on technological and nutritional quality of dried pasta. Wheat flour was substituted by spirulina biomass at three levels: 5, 10 and 20 g/100 g, and a sample without spirulina biomass was made as control. The technological quality was analyzed in terms of cooking properties and texture profile, while pasta surface was observed by confocal microscopy. In addition, protein content, in vitro protein digestibility, phenolic compound content and in vitro antioxidant activity were the major bio-functional characteristics measured. An in vitro starch digestion was performed in order to estimate the glycemic index. Only pasta with 20 g of spirulina / 100 g of flour did slightly modify technological quality parameters; microstructure studies revealed the impact of spirulina addition, resulting in a more heterogeneous surface. The glycemic index was not affected by the addition of spirulina. The incorporation of spirulina resulted in an increase of protein content; however, protein digestibility was reduced as microalgae content increased. Pasta with spirulina exhibited high phenolic compounds content and antioxidant activity compared to control pasta, which could be used to enhance the nutritional profile of the product.