Antioxidant properties of Argentine peanut skins: a comparative study of Runner and Virginia varieties

The objective of this work was to extract antioxidant components from peanut skins using different solvents and to determine antioxidant activity of the extracts. Methanolic, ethanolic, acetonic and aqueous extracts were prepared from defatted and non defatted peanut skins. Total dry matter content and total phenolic content, radical-scavenging activity and antioxidant activity in sunflower oil were determined from the extracts. The peanut skins used in this work had the following proximate composition: 16.60 % oil, 12.32 % protein, 2.83 % ash and 69.8 % other components. High content of total dry matter was found in methanolic (17.11 %), ethanolic (17.70 %) and acetonic (18.54 %) extracts from non defatted peanut skins. The acetonic extract from defatted peanut skins had lower dry matter extraction than the non defatted peanut skin extract. High content of total phenolics was detected in methanolic (158.6 mg/g) and ethanolic (144.1 mg/g) extracts from deffated peanut skins. These last two extracts in concentration of 1 μg/mL, the radical-scavenging activities were 32.59 % in methanolic extract and 31.5 % in ethanolic extract. All extracts (0.05 % w/w) in sunflower oil showed antioxidant activity. This antioxidant activity from the extracts was lower than that activity from BHT.

Background: Peanut skins are a by-product from peanut but with low socio-economic value despite having appreciable amounts of bioactive phytochemicals. Studies are on-going to remove some astringent properties in peanut skins and improve its values. In this study, the in vitro antioxidant activity of raw peanut skins and roasted peanut skins extracts were determined in hydro alcoholic medium. Materials and Methods: The raw and roasted peanut skins powders were each subjected to extraction procedure in 70% methanol for 48 hr. The phytochemical screening including total phenolic and flavonoid contents (TPC, TFC) were determined. The antioxidant activity including DPPH radical scavenging, Fe2+-chelating, ferric reducing antioxidant property (FRAP), OH- radical scavenging and reducing power assays were determined and compared against standard antioxidants. Results: The results showed significantly higher (p<0.05) TPC and total antioxidant capacity in the raw extract compared to the roasted extract. The roasted peanut skins extract showed significantly higher (p<0.05) DPPH radical, OH- radical scavenging capacity, Fe2+-chelating and ferric reducing antioxidant property compared to the raw peanut skins extract. Both extracts each produced concentration dependent percentage inhibitions which were significantly lower than the antioxidant standards used. Conclusion: The results showed that roasting improved the in vitro antioxidant properties of the peanut skins compared to the raw peanut skins. This could add value to its use as functional food component, antioxidant and in animal feed industries.

As an effort to develop functional ingredients and to discover their antioxidant activity, the total polyphenol content, total flavonoid content, 2,2-diphenyl-1-pcrylhydrazyl (DPPH) radical scavenging activity, trolox equivalent antioxidant capacity (TEAC), oxygen radical absorption capacity (ORAC), and ferric reducing antioxidant power (FRAP) of Daphniphyllum macropodum were measured using a methanol extract and various solvent fractions. Based on the result, the total polyphenol content was highest in an ethyl acetate fraction of 212.33±1.05 mg GAE/g where the total flavonoid content was 77.96±0.21 mg QE/g. The DPPH radical scavenging activity was highest in an ethyl acetate fraction (IC50 : 47.10±1.32 μg/mL). The ethyl acetate fraction showed the highest TEAC (1052.23±13.94 mM TE/g), ORAC (9308.71±480.69 mM TE/g), and FRAP (2064.76±42.31 mM FE/g) in antioxidant capacity value. The total polyphenol and flavonoid contents significantly correlated with the antioxidant activity of D. macropodum extracts and fractions. In addition, the survival rate of HaCaT and HepG2 cells at 200 μg/mL was higher than 70%. With these results, it was confirmed that the ethyl acetate fraction of D. macropodum has great antioxidant potential. Thus, it can be expected to be developed into a specific functional ingredient.

This study was performed to evaluate and compare the antioxidant substance content and antioxidant activities of white (Superior) and colored (Hongyoung, Jayoung, Jasim, Seohong, and Jaseo) potatoes. The potatoes were extracted with 80% ethanol and were evaluated for the total polyphenol, flavonoid, and anthocyanin contents and for 1,1-diphenyl- 2-picrylhydrazyl (DPPH)/2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity, reducing power, and ferrous metal ion chelating effect. The total polyphenol, flavonoid, and anthocyanin contents of Hongyoung and Jayoung were higher than white and other colored potatoes. All colored potato extracts, except for Jaseo and Seohong, showed higher ABTS radical scavenging activities than the general white potato extract. Hongyoung and Jayoung had the highest ABTS and DPPH radical scavenging activities. Optical density values for the reducing power of Jayoung and Jaseo at concentration of 2 mg/mL were 0.148 and 0.090, respectively. All colored potato extracts had lower ferrous metal ion chelating effect than the white potato. A significant (P<0.05) positive correlation was observed between total polyphenol content and total flavonoid content (r=0.919), anthocyanin content (r=0.992), and ABTS radical scavenging activity (r=0.897). Based on these results, this research may be useful in developing the Hongyoung and Jayoung cultivars with high antioxidant activities.

Chemical characterization and antioxidant properties of fractions separated from extract of peanut skin derived from different industrial processes

The objective of this study was to evaluate the antioxidant and anti-inflammatory activity of vinegar with added sea tangle (Laminaria japonica) (VAST). To determine the antioxidant activity, DPPH and ABTS radical scavenging activity, reducing power, and total polyphenolic and flavonoid contents were evaluated. The anti-inflammatory activity was determined using lipopolysaccharide (LPS) induced macrophage (RAW 264.7). Finally, the antioxidant and anti-inflammatory activities of VAST were compared with those of vinegar without added sea tangle (VNAST). The antioxidant activity, total polyphenol content, and total flavonoid content were all higher in VAST than in VNAST. Moreover, neither VAST nor VNAST displayed toxicity toward RAW 246.7 cells at up to 200-fold dilution. In LPS-induced RAW 264.7 cells, VAST treatment significantly decreased the production of nitric oxide and inflammatory cytokine (TNF-α) compared with VNAST treatment. Overall, VAST showed exhibited superior antioxidant and anti-inflammatory activities compared with VNAST. These results clearly indicate that VAST has the potential for use as an anti-oxidant and anti-inflammatory agent in functional foods.

In the literature, the chemical composition of Rhododendron tomentosum is mainly represented by the study of isoprenoid compounds of essential oil. In contrast, the study of the content of flavonoids will contribute to the expansion of pharmacological action and the use of the medicinal plant for medical purposes. The paper deals with the technology of extracts from Rh. tomentosum shoots using ethanol of various concentrations and purified water as an extractant. Extracts from Rh. tomentosum were obtained by a modified method that combined the effects of ultrasound and temperature to maximize the extraction of biologically active substances from the raw material. Using the method of high-performance thin-layer chromatography in a system with solvents ethyl acetate/formic acid/water (15:1:1), the following substances have been separated and identified in all the extracts obtained: rutin, hyperoside, quercetin, and chlorogenic acid. The total polyphenol content (TPC) and total flavonoid content (TFC) were estimated using spectrophotometric methods involving the Folin-Ciocalteu (F-C) reagent and the complexation reaction with aluminum chloride, respectively. A correlation analysis was conducted between antioxidant activity and the polyphenolic substance content. Following the DPPH assay, regression analysis shows that phenolic compounds contribute to about 80% (r2 = 0.8028, p < 0.05) of radical scavenging properties in the extract of Rh. tomentosum. The extract of Rh. tomentosum obtained by ethanol 30% inhibits the growth of test cultures of microorganisms in 1:1 and 1:2 dilutions of the clinical strains #211 Staphylococcus aureus and #222 Enterococcus spp. and the reference strain Pseudomonas aeruginosa ATCC 10145.

본 연구에서는 전통 식품 소재로의 활용성을 높이기 위해 참죽나무 순을 동결건조하여 일반성분과 무기질 함량을 측정하였고, 추출용매를 달리하여 얻은 열수 추출물과 70% 에탄올 추출물로부터 총 폴리페놀 및 플라보노이드 함량과 항산화능을 살펴보았다. 참죽나무 순의 일반성분 및 무기질 분석 결과, 조단백질, 조섬유, 칼슘과 칼륨 함량이 높게 측정되었다. 총 폴리페놀과 플라보노이드는 참죽나무 순 분말 열수 추출물보다 70% 에탄올 추출물에서 함량이 더 높았으며, DPPH 유리 라디칼 소거능과 FRAP 또한 70% 에탄올 추출물에서 더 높은 항산화력을 나타냈다. 이상의 결과로 볼 때 참죽나무 순 분말은 영양성과 식이섬유소의 기능성이 높아 식품의 재료로 이용가능성이 높으며, 참죽나무 순 분말로부터 유용성분 용출 및 기능성 증대를 위해서는 70% 에탄올로 추출하는 것이 바람직하다고 생각된다. In this study, the nutritional value, total polyphenol content, total flavonoid content, and antioxidant activity of freeze-dried Cedrela sinensis tender leaf powder were examined. Among the nutritional values, the crude protein, crude fiber, calcium, and potassium were abundantly present in Cedrela sinensis. The Cedrela sinensis powder was extracted with two solvents, 70% ethanol and distilled water (D.W.), to evaluate its functional properties. Total polyphenol and flavonoid contents were measured in the two different extracts, and the extracts were screened for their potential antioxidant activities using tests such as DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), and ABTS radical scavenging assay. Although both extracts exhibited good antioxidant activities against trolox, the ethanolic extract exhibited higher antioxidant activities than the D.W. extract. These results indicated that the Cedrela sinensis powder is a high-valued food ingredient and the extraction with 70% ethanol will be useful as a nutritional source with natural antioxidant activities.

Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts’ antioxidative properties when added to soybean oil.

Variations in amino acid and volatile component contents, and in total flavonoid, polyphenol contents and their vitro antioxidant activities at different aging times of pomelo wine were investigated; scavenging rates against DPPH, ABTS, and ferric reducing antioxidant powers were also explored. Most amino acids reached maximum values in the third aging year; and volatile components of pomelo wine also indicated good wine quality in the third year. Total flavonoid and polyphenol contents in pomelo wine were increased and antioxidant activities enhanced during the first 3 years. Samples aged for 3 years had the highest total flavonoid and total polyphenol contents, and the strongest antioxidant activities (38.23±2.16% for DPPH· scavenging effect, 91.84±4.14% for ABTS· scavenging effect, and 0.90±0.07 mmol/L for FRAP value). These parameters gradually decreased after the 3 year period. A significant (p<0.05) correlation between antioxidant activity, and total flavonoid and polyphenol contents was identified.

In the industrial processing of fruits, co-products are generated, which are often not used. The pracaxi co-product, obtained by cold pressing its seeds, contains phenolic compounds with antioxidant activity, which in this work were extracted and microencapsulated by spray drying. The pracaxi extract was characterized by Fourier-transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC-DAD), and its antioxidant activity was quantified by the ABTS and DPPH assays. Total polyphenol and flavonoid contents in the extract and microparticles were determined by UV-Vis spectrophotometry. Microparticles were then characterized regarding their moisture content, morphology (by scanning electron microscopy), size, polydispersity index and zeta potential. The FTIR spectra revealed functional groups that may be related to phenolic compounds. The extract showed good antioxidant activity according to both selected assays, while the HPLC-DAD analysis evidenced epicatechin as the main compound, whose content was quantified and validated according to the guidelines of recognized national and international agencies. The total polyphenol contents were 20.61 ± 0.20 mg gallic acid equivalent (GAE)/g in the extract and 18.48 ± 0.10 mg GAE/g in the microparticles, while the total flavonoid contents were 28.29 ± 0.70 mg quercetin equivalent (QE)/g and 13.73 ± 0.10 mg QE/g, respectively. Microparticles had a low moisture content, spherical shape, size less than 1 μm and negative zeta potential. Furthermore, they were able to satisfactorily retain phenolic compounds, although in a smaller amount compared to the extract due to small losses resulting from degradation during the drying process. These results, taken as a whole, demonstrate that the pracaxi co-product can be a promising candidate in obtaining products of interest for the cosmetic and food sectors by aiming to exploit its antioxidant activity.

Polyphenols obtained from agricultural and industrial residues are also considered as remarkable sources of natural antioxidants to replace synthetic ingredients. In this study, the contents of total polyphenols (TP) and total flavonoids (TF), antioxidant capacity (AC) and in-vitro bioaccessibility of polyphenols (as gastric and intestinal stages) of the extract from peanut skin using water were investigated. Additionally, the potential use of peanut skin extract in noodle production was researched in order to add functionality to noodle, which is a widely consumed product. The results showed that 71.67 mg gallic acid equivalent (GAE)/g dry matter (DM) of TP, 123.11 mg rutin equivalent (RE)/g DM of TF and 66267.46 mmol ascorbic acid equivalent (AAE)/100g DM of AC were found in peanut skin. After the gastric and intestinal stages, the TP content and AC of the skin extract were found to be lower than the initial (before digestion) value. It was determined that polyphenols were more stable in gastric conditions than in the small intestine. The addition of the skin extract (0.4%) to the noodle dough increased the TP and AC of the final product compared to the noodle without the skin extract (control). It was observed that the stability of the polyphenols from the noodle sample was higher in gastric stage than intestinal one. The addition of peanut skin extract to the noodle dough increased the bioaccessibility of the polyphenols. Therefore, this study showed that peanut skin, as an important source of polyphenols, may be useful for food enrichment.

Objective: Basil has various biological activities, and sufficient research on its extracts can help to clarify the main components that exert biological activity. Methods: Solvents with different polarities were used to extract the basil crude extract (CE), and the total polyphenol (TP) and total flavonoid (TF) contents of extracts were measured. The compounds of extracts were identified using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Their antioxidant and immune-enhanced activities were evaluated. Results: The CE and its four solvent fractions were obtained including petroleum ether extract (PE), ethyl acetate extract (EE), n-butanol extract (BE), and water extract (WE). Among them, BE had the highest TP and TF contents, followed by EE, and all five extracts contained maltol and arbutin. The BE and EE have better 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, while CE with less TP and TF contents showed better 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity than that of BE and EE. Besides, BE and EE also exert a better effect on relevant indicators of immunosuppressive mice than other extracts. Conclusion: The basil extracts (BE and EE), which have higher TP and TF contents, demonstrate better in vitro antioxidant activities and immune-enhancing effects on immunosuppressed mice. This provides a theoretical basis for the application of basil.

In this study, the polyphenol content [total polyphenol content (TPC), total flavonoid content (TFC), and total anthocyanin content (TAC)] and antioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric ion reducing antioxidant power (FRAP), phosphomolybdenum complex assay (PMA), and oxygen radical absorbance capacity (ORAC)] of hydrangea leaf extract, collected based on the cultivation method of each variety, were confirmed, and the correlation between them was evaluated. To confirm the polyphenol content, TPC, TFC, and TAC contents were measured. The TPC was highest in Morning Star (open field) at 4.65 ± 0.00 mg tannic acid equivalent/g, while the TFC was highest in Hydrangea serrata (open field) at 6.44 ± 0.00 mg catechin equivalent/g. The anthocyanin content was highest in H. serrata (open field) at 1.56 ± 0.00 mg CGE/100 g DW. The antioxidant activity (PMA and FRAP) using the reducing power of transition metal ions was 6.17 ± 0.00 mg ascorbic acid equivalent/g in H. serrata (greenhouse) and 140.76 ± 0.00 mM Trolox equivalent (TE)/g in H. serrata (open field). The antioxidant activities measured by radical scavenging assays were highest in White ari (open field) for ABTS at 9.97 ± 0.00 mM TE/g, H. serrata (open field) for DPPH at 28.48 ± 0.00 mM TE/g, and H. serrata (open field) for ORAC at 81.09 ± 0.31 mM TE/g. Our study established a significant quadruple correlation between TPC and radical scavenging activity (ABTS, DPPH, and ORAC) and between transition metal ion (FRAP) and radical scavenging activity (ABTS, DPPH, and ORAC).

This study investigated the quality characteristics of Yanggaeng with different amounts (in ratios of 0, 1, 2, 4% to the total materials) of tumeric powders. The proximate composition and total polyphenol content, antioxidant activities, Hunter's color values, pH, Brix and sensory properties of tumeric hanging were examined. Results of analysis of the proximate composition analysis showed that ash content was increased significantly by adding turmeric powder and the more content of turmeric powder. The higher content of tumeric powder, the higher total polyphenol and total flavonoids contents. Brix and brightness were lowered and yellowness was increased. The sensory properties were highly rated for the control without turmeric powder in four organoleptic (sensory) properties (taste, texture, odor, acceptance) except color. The group with-1% addition of turmeric powder was highly rated in the second place. Key words: Yanggaeng, tumeric powder, quality characteristics, antioxidant activity