Determination of oil palm fruit phenolic compounds and their antioxidant activities using spectrophotometric methods.

There is scarce information on the phenolics of oil palm fruits (Elaeis guineensis). In this study, phenolics were extracted from oil palm fruits and analysed using spectrophotometry for information on the different types of palm phenolics and their antioxidative activities. Analyses of the total phenolic content (TPC), total flavonoid content (TFC), o-diphenols index, hydroxycinnamic acid index, flavonols index and phenol index showed ranges between 5.64 and 83.97 g L−1 gallic acid equivalent (GAE), 0.31–7.53 g L−1 catechin equivalent, 4.90–93.20 g L−1 GAE, 23.74–77.46 g L−1 ferulic acid equivalent, 3.62–95.33 g L−1 rutin equivalent and 15.90–247.22 g L−1 GAE, respectively. The antioxidant assay, 2,2-diphenyl-2-picrylhydrazyl radical scavenging assay, showed antioxidative activities in all the extracts with results ranging from 4.41 to 61.98 g L−1 trolox equivalent. The high antioxidant activities of the oil palm fruit phenolics were also found to increase with increasing TPC and TFC

Effect of thermal treatment and storage on bioactive compounds, organic acids and antioxidant activity of baobab fruit (Adansonia digitata) pulp from Malawi

Bioactive compounds of baobab (Adansonia digitata) pulp from Malawi were investigated. The effect of thermal treatment and storage on selected quality attributes of the juice was also evaluated. Organic compounds were analysed by HPLC; total phenol content (TPC) and total antioxidant activity (FRAP, ABTS and DPPH) were measured by spectrophotometry. Malawi baobab pulp contains high levels of procyanidin B2 (533 ± 22.6 mg/100 g FW), vitamin C (AA + DHA) (466 ± 2.5 mg/100 g FW), gallic acid (68.5 ± 12.4 mg/100 g FW) and (−)-epicatechin (43.0 ± 3.0 mg/100 g FW) and showed a maximum TPC of 1.89 × 103 ± 1.61 mg GAE/100 g FW. The maximum antioxidant activity was 2.81 × 103 ± 92.8 mg TEAC/100 g FW for FRAP, 1.52 × 103 ± 17.1 mg TEAC/100 g FW for ABTS and 50.9 ± 0.43% DPPH for DPPH. Thermal pasteurisation (72 °C, 15 s) retained vitamin C which further showed extended half-life under refrigeration temperature (6 °C). Procyanidin B2, (−)-epicatechin, TPC and antioxidant activity fluctuated during storage. Antioxidant activity was significantly correlated (p ≤ 0.05) with bioactive compounds and TPC

The production of hydrolysates from industrially defatted rice bran and its surface image changes during extraction

BACKGROUND This research employed mild-subcritical alkaline water extraction (SAW) technique to overcome the difficulty of active compounds extractability from an industrially defatted rice bran (IDRB). Mild-SAW (pH 9.5, 130 °C, 120 min) treatment, followed by enzymatic hydrolysis (Protease G6) were applied to produce rice bran hydrolysate (RBH). Response surface methodology was used to identify proteolysis conditions for maximizing protein content and ABTS radical scavenging activity (ABTS-RSA). The microstructural changes during the extraction occurring in the IDRB were monitored. The selected RBH was characterised for protein recovery, yield, antioxidant activities, phenolic profile and hydroxymethylfufural (HMF) content. RESULTS Optimal proteolysis conditions were at 20 mL kg-1 IDRB (E/S) for 6 h. Under these conditions, the yield, ABTS-RSA, Ferric reducing antioxidant power and the total phenolic content of the RBH were 46.1%, 294.22 μmol trolox g-1, 57.72 μmol FeSO4 g-1, and 22.73 mg gallic acid g-1, respectively, with relatively low HMF level (0.21 mg g-1). The protein recovery was 4.8 times greater than the recovery obtained by conventional alkaline extraction. Its major phenolic compounds were p-coumaric and ferulic acids. The microstructural changes of IDRB confirmed that the mild-SAW/Protease G6 process enhanced the release of active compounds. CONCLUSION The process of mild-SAW followed by proteolysis promotes the release of active compounds from IDRB

Effect of storage temperature on Vitamin C, total phenolics, UPLC phenolic acid profile and antioxidant capacity of eleven potato (Solanum tuberosum) varieties

Storage of potato tubers at low temperature affects their metabolism and may alter their phytochemical properties. There is a need to elucidate the changes in antioxidant compounds, activity and enzymes during storage of tubers. Eleven Indian potato varieties were evaluated for antioxidant parameters, after 0, 30, 60 and 90 days of storage at room temperature, 15 °C and 4 °C. Total phenolics (0.0786–0.1546 mg gallic acid equivalents⋅g−1 FW) and vitamin C content (0.0828–0.2416 mg⋅g−1 FW) varied among the varieties and were different with storage temperature; their levels fluctuated during storage but remained above the initial level until the last day of observation. Phenolic acid profiling by UPLC identified 12 compounds among which the most abundant was chlorogenic acid followed by gallic acid, sinapic acid and ellagic acid. Except para-coumaric acid which decreased at 4 °C, all the phenolic acids increased with storage. Caffeic acid, chlorogenic acid, protocatechuic acid and gallic acid mostly correlated with total phenolic content (r = 0.456, 0.482, 0.588 and 0.620, respectively). Antioxidant activity against both DPPH and ABTS radicals increased during the initial days of storage and then dropped to a level comparable or lower than the original value, irrespective of the storage temperature. Correlation study revealed that chlorogenic acid, gallic acid and ferulic acid mostly contributed to antioxidant activity. Activity of both antioxidant enzymes, superoxide dismutase and ascorbate peroxidase, increased initially but then decreased to values lower than the initial level and were not influenced by storage temperature. Correlation with antioxidant activity indicated that the enhancement of reactive oxygen scavenging species in cold stored tubers could result mainly from ascorbate peroxidase activity. Our results demonstrate that storage temperature adversely influences the metabolism and the content of antioxidant compounds in potato tubers, with subsequent increase on their antioxidant capacity

Flavonoids, Phenolics, and Antioxidant Capacity in the Flower of Eriobotrya japonica Lindl.

Flavonoids and phenolics are abundant in loquat flowers. Methanol had the highest extraction efficiency among five solvents, followed by ethanol. Considering the safety and residue, ethanol is better as extraction solvent. The average content of flavonoids and phenolics of loquat flower of five cultivars were 1.59 ± 0.24 and 7.86 ± 0.87 mg/g DW, respectively, when using ethanol as extraction solvent. The contents of both bioactive components in flowers at different developmental stages and in the various flower tissues clearly differed, with the highest flavonoids and phenolics content in flowers of stage 3 (flower fully open) and petal, respectively. The antioxidant capacity was measured using FRAP, DPPH, and ABTS methods. The values of ABTS method was highest, followed by DPPH, the lowest was FRAP, when using vitamin C equivalent antioxidant capacity (VCEAC) as unit. Correlation analysis showed that the ABTS method showed the highest correlation coefficients with flavonoids and phenolics, i.e., 0.886 and 0.973, respectively

Antioxidant and anti-inflammatory activities of freeze-dried grapefruit phenolics as affected by gum arabic and bamboo fibre addition and microwave pretreatment

This is the peer reviewed version of the following article: García Martínez, Eva María, Andújar Pérez, Isabel, Yuste Del Carmen, Alberto, Prohens Tomás, Jaime, Martínez Navarrete, Nuria. (2018). Antioxidant and anti-inflammatory activities of freeze-dried grapefruit phenolics as affected by gum arabic and bamboo fibre addition and microwave pretreatment..Journal of the Science of Food and Agriculture, 98, 8, 3076-3083. , which has been published in final form at http://doi.org/10.1002/jsfa.8807. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] BACKGROUND: Recent epidemiological studies have suggested that phenolic compounds present in grapefruit play an important role in the bioactive properties of this fruit. However, the consumption of fresh grapefruit is low. Freeze dried powdered grapefruit can be an alternative to promote this fruit consumption. To improve the quality and stability of the powdered fruit, the addition of encapsulating and anticaking agents can be used. In this work, different grapefruit powders obtained by freeze drying with addition of gum arabic (1.27 g/100 g), and bamboo fibre (0.76 g/100 g) with and without a pre-drying microwave treatment were compared with the fresh and freeze-dried fruit with no carriers added in order to evaluate the effect of these preservation processes on phenolics content and on its antioxidant (DPPH, ABTS and FRAP) and anti-inflamatory (evaluated in RAW 264.7 macrophages) capacities. RESULTS: Freeze drying and gum arabic and bamboo fibre addition significantly increased the total phenolics, and antioxidant and anti-inflammatory activities (by inhibiting NO production of LPS activated RAW 264.7 macrophages) of grapefruit. An additional increase in these parameters was obtained with a microwave pretreatment before freeze-drying. CONCLUSIONS: The combined addition of gum arabic and bamboo fibre to the grapefruit puree and the application of a microwave pretreatment improve the functional properties of the fruit without showing cytotoxicity in vitro.We thank the Ministerio de Economia y Competitividad and FEDER for financial support given through the Project AGL 2012-39103.García Martínez, EM.; Andújar Pérez, I.; Yuste Del Carmen, A.; Prohens Tomás, J.; Martínez Navarrete, N. (2018). Antioxidant and anti-inflammatory activities of freeze-dried grapefruit phenolics as affected by gum arabic and bamboo fibre addition and microwave pretreatment. Journal of the Science of Food and Agriculture. 98(8):3076-3083. https://doi.org/10.1002/jsfa.8807S3076308398

A novel procedure to measure the antioxidant capacity of Yerba maté extracts

Yerba maté extracts have in vitro antioxidant capacity attributed to the presence of polyphenolic compounds, mainly chlorogenic acids and dicaffeoylquinic acid derivatives. DPPH is one of the most used assays to measure the antioxidant capacity of pure compounds and plant extracts. It is difficult to compare the results between studies because this assay is applied in too many different conditions by the different research groups. Thus, in order to assess the antioxidant capacity of yerba maté extracts, the following procedure is proposed: 100 µL of an aqueous dilution of the extracts is mixed in duplicate with 3.0 mL of a DPPH 'work solution in absolute methanol (100 µM.L-1), with an incubation time of 120 minutes in darkness at 37 ± 1 °C, and then absorbance is read at 517 nm against absolute methanol. The results should be expressed as ascorbic acid equivalents or Trolox equivalents in mass percentage (g% dm, dry matter) in order to facilitate comparisons. The AOC of the ethanolic extracts ranged between 12.8 and 23.1 g TE % dm and from 9.1 to 16.4 g AAE % dm. The AOC determined by the DPPH assay proposed in the present study can be related to the total polyphenolic content determined by the Folin-Ciocalteu assay

Properties of Bread Dough with Added Fiber Polysaccharides and Phenolic Antioxidants: A Review

During breadmaking, different ingredients are used to ensure the development of a continuous protein network that is essential for bread quality. Interests in incorporating bioactive ingredients such as dietary fiber (DF) and phenolic antioxidants into popular foods such as bread have grown rapidly, due to the increased consumer health awareness. The added bioactive ingredients may or may not promote the protein cross-links. Appropriate cross-links among wheat proteins, fiber polysaccharides, and phenolic antioxidants could be the most critical factor for bread dough enhanced with DF and phenolic antioxidants. Such cross-links may influence the structure and properties of a bread system during baking. This article presents a brief overview of our current knowledge of the fate of the key components (wheat proteins, fibers, and phenolic antioxidants) and how they might interact during bread dough development and baking