Antioxidant activity,anthocyanins, and phenolics of rabbiteye blueberry (Vaccinium ashei) fluid products as affected by fermentation

Frozen rabbiteye blueberries (Vaccinium ashei) were processed into juice (BJ), wines made without (BW1) or with (BW2) skin contact fermentation, and vinegars made from BW1 (JV), BW2 (WV) or blueberries (BV). Total phenolics, total anthocyanins, antioxidant activities (beta-carotene bleaching assay and ferric thiocyanate assay), and antiradical activity (DPPH radical-scavenging method) of these fluid products were determined. The differences in total anthocyanin contents of all blueberry products were significant. The BW2 had the highest content of anthocyanins and polyphenols and the highest beta-carotene bleaching activity and antiradical activity. Acetification decreased total anthocyanin content, total polyphenols and antioxidant activities. Correlations indicate that anthocyanins made significant contributions than did phenolics to antioxidant activities of products. The abilities of BJ, BW1 (wine from blueberry juice), and BW2 to inhibit linoleic acid peroxidation were high (∼95%). The abilities of vinegar products to inhibit linoleic acid peroxidation were low. The results indicate that skin-contact fermentation is a better method for obtaining higher antioxidant activity of blueberry products. Also, acetification significantly decreased anthocyanins and antioxidant activities.     

Variation in antioxidant enzyme activities and nonenzyme components among cultivars of rabbiteye blueberries (Vaccinium ashei Reade) and V. ashei derivatives

Fruit from 42 blueberry (Vaccinium species) cultivars, including 36 rabbiteye cultivars (Vaccinium ashei Reade), 3 V. ashei hybrid derivatives and 3 northern highbush (V. corymbosum L.) standards, were evaluated for antioxidant activities (AA), levels of antioxidant enzymes [catalase (CAT), ascorbate peroxidase (AsA-POD), glutathione reductase (GR), glutathione peroxidase (GSH-POD), superoxide dismutase (SOD), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDAR) and guaiacol peroxidase (G-POD)], and antioxidant nonenzyme components [ascorbic acid (ASA) and glutathione (GSH)]. The results of this study showed that cultivars had varying levels of AA, a wide range of antioxidant enzyme activities and various amounts of nonenzyme components. The correlations between AA and all of the enzyme activities or nonenzyme components were positive and high in the 42 cultivars tested in this study. The correlation (R²) values between AA and CAT, SOD, DHAR, MDAR, GSH-POD, GR, G-POD and AsA-POD were 0.91, 0.91, 0.91, 0.91, 0.90, 0.90, 0.90, and 0.90, respectively. The correlations between AA and ASA and GSH were 0.94 and 0.92, respectively. Among all 42 cultivars, ‘Early May’ had the highest activities of the AA, AsA-POD, G-POD, DHAR and MDAR and the highest amounts of ASA and GSH, whereas ‘Elliott’ had the highest levels of GR, GSH and SOD.     

Aroma impact components of rabbiteye blueberry (Vaccinium ashei) vinegars

The aroma impact components of the rabbiteye blueberry vinegars made from wine fermented without skin-contact (JV), wine fermented with skin-contact (WV), or blueberries (BV) were evaluated. Headspace volatiles were isolated by solid-phase microextraction (SPME). Headspace volatiles were analysed by gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GCO). The potent odourants were evaluated by the ‘Osme’ method. Acetic acid, 2/3-methyl-butanoic acid, phenethyl acetate, 2-phenylethanol, octanoic acid, eugenol, and phenylacetic acid were the most important aroma-active compounds identified in all three treatments. The contributions of these compounds to each sample were different. There were more aroma-active compounds identified from the BV than from the other two treatments. The type of fermentation impacts the aroma components of rabbiteye blueberry vinegars.     

Flavonoid constituents and their contribution to antioxidant activity in cultivars and hybrids of rabbiteye blueberry (Vaccinium ashei Reade)

Fruit from 42 blueberry (Vaccinium spp.) cultivars, including 36 rabbiteye cultivars (Vaccinium ashei Reade), three V. ashei hybrid derivatives, and three northern highbush (Vaccinium corymbosum L.) standards were evaluated for antioxidant capacity, individual flavonoid content, and the contribution of each identified phenolic compound to total antioxidant activity. Considerable variation was found in flavonoid content, antioxidant activity, and their contribution to total antioxidant activity among cultivars. Among 42 blueberry cultivars, the rabbiteye ‘Early May’ contained the highest amount of chlorogenic acid, myricetin 3-arabinoside, quercetin derivatives, and delphinidin-, cyanidin-, petunidin-, and malvidin-basis anthocyanins. ‘Early May’ cultivar also had the highest antioxidant activity (88.2 μmol TE/g fw). ‘Owen’, ‘Bluegem’, ‘Clara’, Climax’, and ‘Centurion’ were among the other rabbiteye cultivars that also had high levels of flavonoids and antioxidant activities. In contrast, the pink-fruited V. ashei hybrid, ‘Pink Lemonade’, had the lowest content of flavonoids and lowest antioxidant activity. The mean flavonoid content and antioxidant activity of rabbiteye cultivars was higher than those among northern highbush and V. ashei hybrids. The antioxidant activity of V. ashei hybrid derivatives was derived mainly from chlorogenic acid, myricetin, and quercetin, which contributed 62.5% of total antioxidant activity, whereas anthocyanins (malvidin, petunidin, delphinidin, and cyanidin) were the main contributors to the antioxidant activity of rabbiteye cultivars (76.2%) and northern highbush standards (76.8%). Blueberry cultivars identified to have high phenolic content and high antioxidant activity could be used as parents for future blueberry breeding programmes to develop new blueberry cultivars with higher antioxidant activity and further improve human health.     

Chemical composition,anthocyanins, non-anthocyanin phenolics and antioxidant activity of wild bilberry (Vaccinium meridionale Swartz) from Colombia

Berries of Vaccinium meridionale Swartz native to Colombia were analysed for chemical composition, total phenolic content, anthocyanin content, and antioxidant activity. In addition, high-performance liquid chromatography with photodiode array detection (HPLC–DAD) and HPLC-electrospray ionisation tandem mass spectrometry (ESI–MS/MS) were used to determine anthocyanin and phenolic composition. Anthocyanin content was 329.0 ± 28.0 mg cyanidin 3-glucoside equivalents/100 g (fresh weight) FW and total phenolic content was 758.6 ± 62.3 mg gallic acid equivalent/100 g FW. Cyanidin 3-galactoside was the major anthocyanin while the most abundant non-anthocyanin phenolic was chlorogenic acid.     

Rheological behavior of blueberry (Vaccinium ashei) purees containing xanthan gum and fructose as ingredients

In the present work the influence of temperature, xanthan gum and fructose addition on rheological behavior in steady state of blueberry puree was evaluated. The blueberry pulp was formulated with addition of xanthan gum (1.6, 2.0, 2.5, 3.0 and 3.3%) and fructose (6.6, 10.0, 15.0, 20.0 and 23.4%). Rheological data were obtained by shear rate scan tests in a rotational rheometer, with geometry of concentric cylinders in temperatures of 27, 40, 60, 80 and 93 °C. The thixotropy analysis was made through the calculation of the difference between the areas under up and down cycles’ flow curves. The analysis of the formulation influence on puree viscosity was carried out in two stages: i) selection of an appropriate rheological model for representation of data obtained in experiments and ii) statistical analysis of formulation and temperature influence on rheological parameters of selected model. Three 2-parameter models (Bingham, Ostwald–de Waele and Casson) and three 3-parameter models (Herschel–Bulkley, Mizrahi–Berk and Sisko) were tested. Based on the values of correlation coefficients and variance of the estimated parameters, Casson model was chosen for fitting of experimental data. The content of xanthan gum appears as a determinant variable of the rheological behavior of the puree, both at short and long times. The correlation among the variables studied was represented through statistical models which could be used for the development of formulations with specified viscosity in the range of additive concentrations studied.     

Chemical constituents of the leaves of rabbiteye blueberry (Vaccinium ashei) and characterisation of polymeric proanthocyanidins containing phenylpropanoid units and A-type linkages

Chemical constituents of the leaves of rabbiteye blueberry (Vaccinium ashei READE) were investigated in detail. The major phenolic components were caffeoyl quinic acids, flavonol glycosides, flavan-3-ols and proanthocyanidins. Catechins and proanthocyanidins having additional phenylpropanoid units, such as cinchonains, kandelins and mururins, characterised the polyphenols of this plant. Among them, vaccinin A, an isomer of mururin A, was found to be a new compound, and the structure was characterised by spectroscopic methods. The most abundant polyphenols (11.3% of freeze-dried leaves) were oligomeric proanthocyanidins. Thiol degradation with mercaptoethanol indicated that the polymer was constituted of (+)-catechin and (−)-epicatechin as the terminal units and (−)-epicatechin, procyanidin A-2, and cinchonains Ia and Ib as the extension units. Mass spectral analysis suggested the presence of at least dodecamers with A-type linkages and phenylpropanoid moieties.     

Antioxidant anthocyanins screening through spectrum-effect relationships and DPPH-HPLC-DAD analysis on nine cultivars of introduced rabbiteye blueberry in China

Blueberries have drawn growing attention in China for various benefits to health. Nine rabbiteye blueberry cultivars which were introduced into China were systematically assessed based on two aspects of chemical profiles and antioxidant activity. The former was achieved by HPLC fingerprints, and the latter in terms of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging capacity was evaluated with a novel HPLC method. Subsequently, the predominant active anthocyanins were screened from these coloured biological samples by two useful methods, respectively. In method I, the spectrum-effect relationships between HPLC fingerprints and the antioxidant activities of blueberry extracts were investigated, whereas in method II, HPLC analysis followed pre-column reaction of samples with DPPH. The results indicated that Gardenblue and Powderblue showed stronger antioxidant activities among all introduced cultivars, and delphinins and anthocyanidin-3-glucosides were the main contributive components to the antioxidant activities of blueberries. This would be helpful to the quality-oriented cultivation of blueberry in China.     

Phenolic profile and antioxidant activity of highbush blueberry (Vaccinium corymbosum L.) during fruit maturation and ripening

The phenolic profile and quantitative composition of blueberries as well as the corresponding antioxidant activity of blueberries is well documented. Unfortunately, little is reported on the development of phenolic compounds and antioxidant activity during fruit maturation and ripening. In the present study, the total phenolic content and main phenolic compounds of four highbush blueberry cultivars (Vaccinium corymbosum L.) were analyzed at five stages of maturation and ripening. Antioxidant activity was screened with electron spin resonance spectrometry and trolox equivalent antioxidant capacity (TEAC) assay. An adequate picture of phenolic compounds developed during maturation and ripening was determined using HPLC-DAD. Anthocyanins of all varieties increased during successive harvest stages; meanwhile flavonols and hydroxycinnamic acids decreased from unripe green to ripe blue stage of berry ripening. Blueberry antioxidant activity, as well as total phenolic content tended to decrease during ripening.     

Antioxidant capacities vary substantially among cultivars of rabbiteye blueberry (Vaccinium ashei Reade)

Fruits from forty‐two blueberry cultivars, including thirty‐six rabbiteye (Vaccinium ashei Reade), three V. ashei hybrid derivatives and three northern highbush (V. corymbosum L.) standards, were evaluated for their antioxidant activities against peroxyl free radicals (ROO˙), hydroxyl radicals (OH˙), hydrogen peroxide (H₂O₂), superoxide radicals () and singlet oxygen (¹O₂) radicals. The differences in scavenging capacities for these radicals among forty‐two selected blueberry cultivars were significant. Oxygen radical absorbance capacity values ranged from 33.8 to 118.7 μmol Trolox equivalents (TE) g fresh wt^?1, 196.1 to 518.8 μmol TE g dry wt^?1 and 7.1 to 22.2 μmol cm^?2‐surface area. Extracts from fruit of pure rabbiteye had higher levels of scavenging capacities of oxygen species , ¹O₂ and H₂O₂ compared to V. ashei hybrid derivatives and northern highbush blueberry standards. The rabbiteye cultivars ‘Early May’ and ‘Centurion’ had the highest scavenging capacity for the reactive oxygen species, not only for ROO˙ and ˙OH, but also for , ¹O₂ and a strong oxidant, H₂O_2. In contrast, ‘Pink Lemonade’ (pink‐fruited) had the lowest ability to inhibit free radical activity of ROO˙,˙OH, ¹O_2, and H₂O_2.‘Snowflake’ had the lowest scavenging capacity for . Blueberry cultivars with high antioxidant activity and radical scavenging capacity have potential to improve human health and can possibly be used as parents for future blueberry breeding programs to develop new blueberry cultivars with higher antioxidant activity.     

Antioxidant capacity,phenolics and isoflavones in soybean by-products

This study aimed to determine proximate composition, antioxidant capacity, total phenolic content, isoflavones and free phenolic compounds in soy by-products. High carbohydrate and protein contents were found in grade A soymilk powder (GASP) compared to grade B soymilk powder (GBSP) and soy husk powder (SHP). Ash, moisture and total dietary fibre contents were reported to be the highest in soy husk, while GBSP had the highest fat content. Antioxidant capacity as assessed using β-carotene bleaching assay was in the order of SHP ≈ GBSP > GASP, and the ranking order of the Trolox Equivalent Antioxidant Capacity (TEAC) value was GASP ≈ GBSP > SHP, while the Ferric Reducing Antioxidant Power (FRAP) value was GASP > GBSP > SHP. The total phenolic content was in the range of 62.44–103.86 mg GAE/100 g wet weight, and the major phenolic compounds in free form were ferulic, vanilic as well as gallic acids. Acid hydrolysis increased the amount of total extractable isoflavone in all soy samples.     

Antioxidant activity of barley as affected by extrusion cooking

Grit from different hulled barley cultivars was subjected to extrusion cooking and the effect of extrusion moisture and temperature on the antioxidant properties was studied. A significant decrease in the total phenolic content (TPC) and total flavonoid content (TFC) was observed upon extrusion and a further decrease of 8-29% in TPC and 13-27% in TFC was observed when both the feed moisture and extrusion temperature were increased. The antioxidant activity (AOA) increased significantly upon extrusion and this increase was the highest (36-69%) at 150 °C and 20% feed moisture. The increase in feed moisture and temperature significantly increased the metal chelating activity. The reducing power decreased significantly upon extrusion as compared to their corresponding control samples. Extrusion lead to a greater increase in non-enzymatic browning (NEB) index however, increasing the moisture content of feed decreased the NEB index by 3-29% (at 180 °C) and 1-17% (150 °C), while increasing the temperature increased the NEB significantly.     

蓝莓果酒发酵期间抗氧化成分及活性研究

对蓝莓果酒发酵期间的花色苷含量、总酚含量、自由基清除率、还原力的动态变化进行了监测,并用R2.5.1相关性分析对所测指标进行相关性分析、聚类分析、回归分析、残差自相关性诊断。结果表明,发酵期间花色苷及总酚的含量缓慢下降;还原力和自由基清除能力与总酚和花色苷含量的变化规律一致,主要呈递减趋势;花色苷含量、总酚含量、自由基清除率、还原力有显著的相关性（p <0.01）;在聚类树状图上总酚与自由基清除率、还原力距离更近;以总酚含量预测抗氧化活性效果最佳,其与自由基清除率和还原力的回归方程依次为Y1=0.2976X+11.2918和Y2=2.052×10-3X+0.4608。     

UV-B-induced changes of volatile metabolites and phenolic compounds in blueberries (Vaccinium corymbosum L.)

There are many reports on the potential consequences of UV-B radiation on plants, but there is a rather limited understanding of the effect on secondary plant metabolites, e.g. phenolic compounds and volatiles, at all. The popularity of highbush blueberries (Vaccinium corymbosum L.) is mainly due to its unique flavour and its high content of bioactive compounds, i.e. phenolic compounds. However, information on UV-B elicitor mediated changes on secondary plant metabolites on blueberries is scanty. In the present study, blueberry fruits were harvested and exposed to UV-B radiation with different dosage and adaptation times. With regard to volatile secondary metabolites, C₆-aldehydes, terpenes and ketones, an increase of the relative peak area was observed after both UV-B treatments (0.075 and 0.15 Wh/m² = low [L] and high [H] dosage, respectively). Furthermore, there was a strong influence of the adaptation time. Increasing relative peak areas were determined already after a short adaptation time (2 h) at both, low and high UV-B dosages, but after 24 h adaptation time relative peak areas decreased significantly. However, alcoholic compounds, as degradation products of aldehydes, showed opposite results. In contrast, the non-volatile phenolic compounds revealed a continuously increase with UV-B intensity.     

蓝莓花色苷及冻干粉对猕猴桃籽油抗氧能力的研究

以贵州蓝莓为原料,分别采用冷冻干燥法提取得到蓝莓冻干粉以及用乙醇为溶剂从蓝莓中提取得到蓝莓花色苷。采用Schaal烘箱法,研究了蓝莓花色苷及冻干粉对猕猴桃籽油抗氧化能力。以猕猴桃籽油的过氧化值(POV)为评价指标,比较了抗坏血酸、BHT、柠檬酸与蓝莓花色苷及冻干粉对猕猴桃籽油的抗氧化作用。结果表明,蓝莓花色苷及其冻干粉可以有效地延缓猕猴桃籽油的氧化,且随着试验时间增加,抗氧化作用效果越显著。蓝莓花色苷及其冻干粉的抗氧化不如坏血酸、BHT。另外,抗坏血酸对蓝莓冻干粉具有明显的增强抗氧化作用。     

Influence of anthocyanins and derivative pigments from blueberry (Vaccinium myrtillus) extracts on MPP intestinal uptake: A structure–activity approach

The aim of the present study was to investigate the influence of an anthocyanin extract (extract I), and two other derivative extracts (extracts II and III), which are being developed aiming to be further applied in the food industry, on intestinal uptake of organic cations. For this purpose, the effect of these compounds on ³H-MPP⁺ uptake was evaluated in Caco-2 cells (an enterocyte-like cell line derived from a human colonic adenocarcinoma).     

Antioxidant phenolics and their microbial production by submerged and solid state fermentation process: A review

BackgroundBioactive phenolic compounds have recently received great attention in the food and clinical sectors due to their antioxidant potential. Extensive studies have been carried out to explore antioxidant potential of different phenolics from various natural sources in order to replace the use of health hazard synthetic antioxidants in food products.Scope and approachThe present review aims to provide an update of existing state-of-art and future prospect of both submerged fermentation (SmF) and solid-state fermentation (SSF) processes for the production/extraction of bioactive phenolics utilizing various substrates and microorganisms. Studies on enhancement of antioxidant potentials by increasing phenolics content of food materials including cereals and legumes by mainly SSF are reviewed and discussed thoroughly.Key findings and conclusionsMicrobial fermentation processes have been established as a potent tool for the production of antioxidant phenolic compounds due to their cost-effectiveness and environmental advantages. Extraction of phenolics through fermentation process is by far a more efficient process considering that conventional extraction methods using organic solvents do not allow complete release of bound phenolics from plant materials. During fermentation process, antioxidant phenolics are either produced by microorganisms through secondary metabolic pathway or released from the matrix of the substrate by extracellular enzymatic action. Fermentation technology is no doubt proving to be a boon for the food industry; however, extensive in vivo and toxicological researches are essential before the application of antioxidant-rich fermented foods for human health benefits.