Antioxidant activities of onion (Allium cepa L.) peel extracts produced by ethanol,hot water,and subcritical water extraction

Onion (Allium cepa L.) peels were extracted by ethanol, hot water and subcritical water (SW) extraction and their antioxidant activities were evaluated. Extraction yields of SW extraction were 4-fold higher than ethanol extraction. However, the ethanol extraction increased the total phenolics contents (327.5 mg GAE/g extract) and flavonoids contents (183.95 mg QE/g extract) in the onion peel extract. The onion peel extracts by ethanol extraction showed greater DPPH radical scavenging activities and greater antioxidant activities determined by ferric thiocyanate assay than those by hot water extraction and SW extraction at 165°C. Antioxidant activity of onion peel extract by SW extraction at 110°C was similar to that of ethanol extraction. HPLC profiles revealed that SW extraction at lower temperature (110°C) increased the concentration of quercetin. These results demonstrated that the onion peel extracts produced by SW extraction technique have great potential as a source for useful antioxidant.     

黄色洋葱皮不同溶剂多酚提取物的总酚、总黄酮含量及抗氧化活性

以黄色洋葱皮为原料,分别利用70%甲醇、70%乙醇和70%丙酮作为提取溶剂进行多酚类物质提取。测定提取物中的总酚含量、总黄酮含量并研究其抗氧化活性(DPPH自由基清除能力、ABTS自由基清除能力以及铁还原能力)。研究结果显示:利用甲醇作为提取剂所得的多酚类物质提取率最高(12.35%),并且提取物中总酚和总黄酮含量最高,分别为83.17、34.31 mg/g。同时,甲醇提取物对DPPH自由基和ABTS自由基的半抑制浓度IC₅₀分别为0.059和0.031 mg/mL,低于抗坏血酸而高于乙醇提取物和丙酮提取物。     

Effects of onion on physicochemical properties,lipid oxidation and microbial growth of fresh pork patties

Onions with or without heating (100 °C, 30 min) were extracted with water or methanol, and antioxidant and antimicrobial activities of onion extracts were evaluated. Product characteristics of fresh pork patties containing various onion extracts were measured during refrigerated storage. Water extracts of onions showed higher extraction yield and iron chelating ability than methanol extracts (P < 0.05), whereas, the latter was more effective than the former in phenolic compounds and reducing power (P < 0.05). The addition of onion extracts [water extract from fresh onion (WEFO), methanol extract from heated onion (MEHO) and their combinations (WEFMEHO)] to pork patties decreased redness, increased yellowness, and inhibited lipid peroxidation (P < 0.05). One per cent of WEFMEHO in pork patties had antioxidant activities as effective as butylated hydroxyl toluene (BHT, 0.01%). Redness and yellowness decreased and increased with the addition of onion extract, respectively (P < 0.05).     

Evaluation of pre‐heating and extraction solvents in antioxidant and antimicrobial activities of garlic,and their application in fresh pork patties

The objectives of this study were to screen the optimum conditions for antioxidant and antimicrobial activities of garlic as affected by pre‐heating and different extraction solvents, and to evaluate the antioxidant and antimicrobial effects of these extracts in ground meat during refrigerated storage. Methanol extracted garlic had a greater total phenolic content, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH)‐radical scavenging activity and reducing power than water extracted one (P < 0.05), whereas the latter had a greater yield and iron chelating ability than the former (P < 0.05). Moreover, water extract from fresh garlic (WEFG) and methanol extract from heated garlic (MEHG) produced an inhibition zone against Escherichia coli O157:H7 and Listeria monocytogenes. The addition of garlic extracts (WEFG, MEHG and their combinations WEFMEHG)) to pork patties decreased the pH, hunter a values (redness), thiobarbituric acid substances values and the number of total plate count and Enterobacteriaceae (P < 0.05), while the hunter b values (yellowness) increased (P < 0.05). Results of this study indicated that the use of the garlic extracts was able to control lipid oxidation and microbial growth in pork patties.     

The antioxidative properties of Holy basil and Galangal in cooked ground pork

The ethanolic extracts from Holy basil and Galangal were examined for their extraction yield, total phenolic content, antioxidant activity against a β-carotene-linoleic acid emulsion system, DPPH scavenging activity and reducing power. Ethanolic extracts of Holy basil exhibited higher extraction yield, total phenolic content, antioxidant activity, DPPH scavenging activity and reducing power than ethanolic extracts of Galangal. Antioxidative efficiency to inhibit lipid oxidation of dried Holy basil and dried Galangal powder, ethanolic extracts of Galangal and Holy basil and commercial antioxidant mixture in cooked ground pork was investigated during refrigerated storage at 5°C for 14 days. The quantitative measurements of thiobarbituric acid reactive substances (TBARS), conjugated diene, peroxide value (POV) and hexanal content were used as indicators of lipid oxidation. Increased levels of TBARS value, POV and hexanal content were noticed in all meat samples during storage, however most marked in cooked ground pork without antioxidants, whereas conjugated diene tended to decrease with increasing storage time. Ranking of the treatment in order of their antioxidant effectiveness showed that commercial antioxidant mixture (0.3% citric acid+0.5% ascorbic acid+0.02% α-tocopherol)>dried Galangal powder>dried Holy basil powder>ethanolic extracts of Galangal>ethanolic extracts of Holy basil>control. Furthermore, in cooked ground pork samples a high correlation between TBARS value and hexanal contents was obtained.     

Functional properties of raw and cooked pork patties with added irradiated, freeze-dried green tea leaf extract powder during storage at 4 °C

Functional and sensory properties of raw and cooked pork patties with added irradiated freeze-dried green tea leaf extract powder were studied. Components of green tea were extracted by 70% ethanol, and the extract was irradiated to obtain a bright color. The irradiated green tea extract was freeze-dried and the powdered sample (0.1%) was added to the pork patties (Trt C). Pork patties without any ingredient (Trt A) and with nonirradiated, freeze-dried green tea extract powder (Trt B) were also prepared for comparison. Lipid oxidation, radical scavenging effect, color, and sensory properties of pork patties with treatments were analyzed at 5-day intervals for 15 days with storage at 4?°C. The lipid oxidation had a lower (P<0.05) and radical scavenging effect was greater (P<0.05) in the raw and cooked pork patties with added Trt B and Trt C, than those of Trt A (control). The pork patties with Trt B and Trt C had a higher Hunter color a*-value and less cooking loss than that of Trt A. Sensory panelists preferred the odor of the raw pork patties and color of the cooked pork patties of Trt C (P<0.05). Generally, no significant difference between Trt B and Trt C was found. Therefore, irradiated, freeze-dried green tea extract powder can be used for producing functionally-improved meat products.     

Antioxidant potential of curry (Murraya koenigii L.) and mint (Mentha spicata) leaf extracts and their effect on colour and oxidative stability of raw ground pork meat during refrigeration storage

The aim of this study was to investigate the antioxidant activity of different solvent extracts of curry and mint leaf and their effect on colour and oxidative stability of raw ground pork meat stored at 4 ± 1 °C. The results indicated that among the two individual leaf categories, the ethanol extract of curry leaf (EHEC) and the water extract of mint leaf (WEM) showed higher DPPH and ABTS⁺ activity. EHEC also exhibited the highest total phenolic contents while these were the lowest for WEM. WEM showed the highest superoxide anionic scavenging activity (%). The pork meat samples treated with EHEC and WEM showed a decrease in the Hunter L- and a-values and a increase in b-value during storage at 4 °C. However, the pH and TBARS values were higher in control samples irrespective of storage periods. In conclusion, EHEC and WEM have the potential to be used as natural antioxidants to minimise lipid oxidation of pork products.     

石榴皮提取物对猪肉饼冷藏过程中脂肪氧化稳定性的影响

选用陕西省优势天然资源产物石榴皮提取物,测定其总酚及总黄酮含量,采用5 种方法对其抗氧化活性进行评价,并研究不同质量浓度石榴皮提取物的添加对猪肉饼冷藏过程中脂肪氧化稳定性的影响。结果表明：石榴皮提取物具有高效的2,2’-联氮双-（3-乙基苯并噻唑林-6-磺酸）二胺盐（2,2’-azinobis-（3-ethylbenzothi azoline-6-sulfonic acid）ammonium salt,ABTS）自由基（ABTS＋·）、?OH和1,1-二苯基-2-三硝基苯肼自由基清除能力以及一定的金属离子（Fe2＋）螯合能力;石榴皮提取物的添加（0.01%、0.05%和0.10%）能明显减缓猪肉饼冷藏过程中的脂肪氧化;总体来说,随着石榴皮提取物添加量的增加,其脂肪氧化抑制效果增强,且添加0.01%石榴皮提取物时的抑制效果与添加0.01%（以脂肪含量为基准）丁基羟基茴香醚相当。     

Antioxidant activity of microwave-assisted extract of longan (Dimocarpus Longan Lour.) peel

The longan (Dimocarpus Longan Lour.) peel was extracted with 95% ethanol employing microwave-assisted extraction and Soxhlet extraction method, the total phenolic content of microwave-assisted extract of Langan peel (MEL) and Soxhlet extract of Langan peel (SEL) reached 96.78 mg/g and 90.35 mg/g dry weight, respectively, expressed as pyrocatechol equivalents, which were quantified using Folin–Ciocalteu reagent. Subsequently, antioxidant properties of two extracts were investigated employing various established systems in vitro including 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, hydroxyl radical scavenging assay using a new resonance scattering (RS) method, reducing power and total antioxidant capacity. MEL and SEL showed excellent antioxidant in all test systems compared to synthetic antioxidant 2,6-di-ter-butyl-4-methylphenol (BHT) and the antioxidant activities of MEL were all superior to those of SEL. Furthermore, the suitability of MEL and SEL as substitute of BHT were determined in peanut oil, and the decrease of lipid oxidation were monitored using thiobarbituric acid-reactive substances (TBARS) assay. MEL and SEL treatment significantly (P < 0.05) reduced lipid oxidation in peanut oil compared to the control. No significant differences (P=0.05)$P=0.05)$ in lipid oxidation were detected between MEL, SEL and BHT samples of peanut oil.     

Antioxidant activity of black currant (Ribes nigrum L.) extract and its inhibitory effect on lipid and protein oxidation of pork patties during chilled storage

This experiment was conducted to assess the antioxidant efficacy of black currant (Ribes nigrum L.) extract (BCE) in raw pork patties during chilled storage. The extracting conditions of frozen BCE including ethanol concentrations (0-100%) and extracting times (0.25-12h) were studied. BCE extracted with 40% ethanol for 2h had the highest anthocyanin content, the strongest radical scavenging activities as well as the second strongest reducing power. BCE was condensed and added to pork patties at 5, 10 or 20 g/kg. Compared with the control, BCE treatments significantly decreased the thiobarbituric acid-reactive substance values and carbonyls formation and reduced the sulfhydryl loss of pork patties in a dose-dependent manner (P<0.05), which showed that the BCE significantly inhibited lipid and protein oxidation. The BCE-treated patties showed significantly higher redness (P<0.05) than the control. The findings demonstrated strong potential for BCE as a natural antioxidant in meat and meat products.     

大叶紫薇叶提取物抗氧化性能的研究

采用不同溶剂对大叶紫薇叶进行浸泡提取,计算提取率,并用FolinCiocalteu方法测定总酚含量;采用DPPH分析法和FRAP分析法评估了不同溶剂提取物的抗氧化活性,选出抗氧化活性最高的提取物添加到猪肉中,于4℃光照下贮存12d,通过测定贮存期间猪肉的TBARS值、pH值和亨特L、a、b值,评估了提取物抗脂质氧化、防腐保鲜和护色作用,并与BHT、VE、茶多酚比较。结果表明,不同溶剂提取物显示出不同的抗氧化活性,其中甲醇提取物抗氧化活性最高(高于BHT),其提取率和总酚含量也最高。大叶紫薇叶甲醇提取物在生猪肉中具有明显的抗脂质氧化和防腐保鲜的作用,且随着提取物含量的增大,抗氧化的效果增强,有明显的量效关系。     

洋葱皮乙醇提取物对冷却牛肉颜色、脂质和蛋白质氧化稳定性的影响

将牛肉切片在3种浓度（0.5 %、1.0%、2.0%）的洋葱皮乙醇提取物（Ethanol Extract of Onion Skin,EEOS）溶液中浸渍后在4 ℃条件下冷藏12 d,并与空白对照组和添加了抗坏血酸（ascorbic acid,V_C）的处理组进行比较,分析EEOS对牛肉在冷藏期间的颜色褐变、脂肪和蛋白质氧化以及腐败程度的影响。结果表明:EEOS总酚含量较高,具有很强的自由基清除活性;添加EEOS可延缓牛肉pH上升,提高颜色稳定性,减少高铁肌红蛋白的生成,同时延缓脂肪和蛋白的氧化进程。2% EEOS有效降低了牛肉样品硫代巴比妥酸反应物（Thiobarbituric acid reactive substances,TBARS）和蛋白质羰基含量,与空白对照组相比分别降低56.9%和17.6%。此外,2% EEOS还可显著降低挥发性盐基氮（Total Volatile Basic Nitrogen,TVB-N）的含量（P<0.05）。因此,添加2% EEOS可抑制牛肉冷藏期间的颜色褐变和脂肪、蛋白质的氧化,可在牛肉冷藏保鲜中作为天然抗氧化剂。     

黑小麦麸皮抗氧化活性成分提取及其抗氧化能力评价

黑小麦麸皮是黑小麦加工过程中的副产物,其富含多种生理活性物质,包括花青素、酚酸类物质、膳食纤维等。以黑小麦麸皮为原料,利用不同溶剂对其抗氧化活性成分进行提取并对其抗氧化能力评价研究。结果表明,75%乙醇提取物干物质得率最高,为10.72%;50%乙醇提取总酚含量最高,为2.9 mg/100 mL;50%乙醇提取物对1,1-二苯基-2-三硝基苯肼（DPPH）清除力最强,75%乙醇提取物对DPPH抗氧化物提取能力最强;75%丙酮提取物对2,2′-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）清除力最强,75%甲醇提取物对ABTS抗氧化物提取能力最强。综合比较得出,50%乙醇更适于黑小麦麸皮抗氧化活性成分提取。     

石榴皮提取物对生猪肉饼品质的影响

研究石榴皮提取物的抗氧化性能及不同质量分数（0.01%、0.05%和0.10%）石榴皮提取物的添加对生猪肉 饼pH值、蒸煮损失、色差和冷藏过程中脂肪及蛋白氧化的影响。结果表明：石榴皮提取物富含多酚和黄酮,其总 抗氧化能力、自由基清除能力、Fe2＋螯合能力随石榴皮提取物质量分数增大而增强;石榴皮提取物的添加对生猪肉饼的 pH值和蒸煮损失率无显著影响,但对生猪肉饼的亮度值、红度值有一定的负面作用;石榴皮提取物能有效抑制生猪肉 饼冷藏过程中氢过氧化物、丙二醛及蛋白羰基生成,且质量分数越高抑制效果越好,整体效果优于丁基羟基茴香醚。     

Anthocyanin characterization and bioactivity assessment of a dark blue grained wheat (Triticum aestivum L. cv. Hedong Wumai) extract

Defatted bran of dark blue grained wheat (Triticum aestivum L., cv. Hedong Wumai) was extracted using ethanol and chemically characterized by HPLC and ESI-MS. Cyanidin-3-glucoside was the predominant anthocyanin in the pigmented wheat which also contained cyanidin-3-galactoside, pelargornidin-3-glucoside, and peonidin-3-glucoside. Ferulic acid was identified as the major simple phenolic acid, with lesser amounts of p-hydroxybenzoic acid, caffeic acid, syringic acid and p-coumaric acid also present. Anthocyanins were separated from phenolic acids using solid phase extraction, and respective fractions were determined for DPPH radical, ABTS radical scavenging tests as well as oxygen radical absorption assay. Results showed that 69% of the overall free radical scavenging capacity of dark blue grained wheat was attributed to the anthocyanin content, compared to 19% for the extractable phenolic acids. In cell based models, the pigmented wheat extract significantly suppressed both hydrogen peroxide-induced intracellular oxidation (p < 0.01) and bacterial lipopolysaccharide-induced nitric oxide (p < 0.05) production. These data report for the first time the major phytochemical composition of pigmented grained wheat and associated bioactivity towards free radical scavenging and suppression of ROS and RNS activity.     

Evaluation of the Ability of Eleutherine americana Crude Extract as Natural Food Additive in Cooked Pork

ABSTRACT:  The scavenging activities of crude ethanolic extract from  Eleutherine americana , on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals were investigated. The results revealed that the extract produced IC₅₀ values of 8.4 μg/mL and 0.78 mg/mL on DPPH and hydroxyl free radicals, respectively. The total phenolic content of the extract was determined using the Folin–Ciocalteu reagent and the crude extract yielded high phenolic content of 4.56 μmol gallic acid equivalent per milligram dried extract. The extract, at different concentrations, was incorporated into pork, cooked in the microwave, and stored at 4 °C for 9 d. The crude extract demonstrated antioxidant activity, which increases with increased extract concentrations and retarded lipid oxidation in the cooked pork. Antibacterial activity of the extract against  Staphylococcus aureus  in the cooked pork revealed that at a concentration of 10.8 mg/100 g, the extract reduced the bacterial population by 0.57 log compared to control at 9 d of storage. The sensory results revealed that the pork samples treated with the extract and the control sample were not significantly different from day 0 to 6; however, on day 9 the treatments were significantly scored higher than the control. Furthermore, addition of the extract led to an increase in the redness values of the pork and this was acceptable from the sensory point of view.  E. americana  crude extract could be a promising novel antioxidant to prevent lipid oxidation and a potential natural color enhancer of red meat and meat products.     

Inhibition of Lipid Oxidation and Rancidity in Precooked Pork Patties by Radical‐Scavenging Licorice (Glycyrrhiza glabra) Extract

This study investigated the efficacy of licorice extract (LE) to curtail lipid oxidation and protect sensory attributes of ground pork during refrigerated and frozen storage. Pork patties (20% fat) were formulated with 0%, 0.02%, 0.05%, and 0.1% (meat basis) LE or rosemary extract (RE) as comparison or 0.01% (fat basis) BHA with 0 or 1.5% NaCl. Raw and precooked (75 °C) patties were packaged in polyvinylchloride overwrapped trays and stored at 2 °C up to 7 and 14 d, respectively, or at –20 °C up to 6 mo. Lipid oxidation (thiobarbituric acid‐reactive substances [TBARS]) and sensory attributes of stored patty samples were evaluated, radical scavenging activity of the LE was measured, and the active phenolic compounds were identified. Cooking yield (<85%) was similar among antioxidant treatments, and lipid oxidation was minimal in refrigerated or frozen raw samples. However, TBARS values in refrigerated precooked control patties (0.22 mg/kg) rose to 9.3 to 9.4 mg/kg after 14 d, compared to 3.4 to 4.4 and 4.4 to 6.9 mg/kg in patties treated with 0.1% LE and RE, respectively. In frozen precooked samples, TBARS (0.22 mg/kg) increased to 1.3 mg/kg (P < 0.05) in control patties after 6 mo and had no significant change in patties treated with 0.1% LE or 0.01% butylated hydroxyanisol. Sensory panel evaluation confirmed strong inhibition of rancidity production by LE, corroborating its remarkable antiradical activity due to the presence of multiple phenolics. The results indicate that licorice has great potential as a natural antioxidative additive to extend the shelf‐life of precooked pork.     

Incorporation of yellow onion peel extract into the funoran-based biodegradable films as an antioxidant packaging material

This study was conducted to develop a biodegradable antioxidant film using yellow onion peel extract (YOPE) and funoran extracted from Gloiopeltis furcata. The mechanical, optical and antioxidant properties of the funoran films containing various amounts of YOPE (0.3%, 0.5% and 1.0%) were examined. YOPE dose-dependently increased the flexibility as well as the DPPH and ABTS free radical scavenging activities of the funoran films. Additionally, the total phenolic and total flavonoid contents of the funoran films increased from 31.92 to 61.31 mg gallic acid equivalent g⁻¹ film and from 21.80 to 79.22 mg quercetin equivalent g⁻¹ film after the incorporation of YOPE, respectively. These results suggest that the funoran-based film incorporated with YOPE, which was prepared from underutilised red alga and discarded onion peel, can be used as an antioxidant biodegradable packaging material.     

不同品种山药皮醇提物的抗氧化性能

本文以菜山药皮为研究对象,烘干后粉碎过筛,通过不同浓度乙醇溶液对菜山药皮粉浸提回流,测定醇提物中多酚、黄酮、皂苷等活性物质含量及以其对DPPH自由基、羟基自由基、超氧阴离子自由基的清除能力以及对铁离子的还原力,评价其抗氧化能力,从而选择出最佳乙醇浓度。然后对铁棍山药皮、蕲春山药皮、利川山药皮、佛手山药皮进行最佳乙醇浓度的浸提,并分析其活性成分和抗氧化能力差异。结果表明:菜山药皮经70%乙醇提取所得到的醇提物,活性成分和抗氧化能力较高;不同品种山药皮醇提物中活性成分和抗氧化能力差异显著(p<0.05),且不同品种山药皮醇提物中活性成分含量与抗氧化能力之间存在显著相关性(p<0.05);其中佛手山药皮醇提物多酚(2.46 mg/g)、皂苷、黄酮以及其他活性成分总量均显著高于其他四种山药皮醇提物(p<0.05),多酚、皂苷、黄酮、活性成分总量分别为12.52、6.12、21.06 mg/g,对羟基自由基、DPPH自由基的清除率以及铁离子还原力也处于较高水平,而对于超氧阴离子自由基的清除率以及亚油酸氧化的抑制能力,佛手山药皮醇提物虽不是最优的,但也处于较高的水平,因此综合来看,佛手山药皮的抗氧化效果要优于其他3种山药皮。     

Antioxidant activity of ethanolic extract of Cortex fraxini and use in peanut oil

Cortex fraxini was extracted with 95% ethanol to obtain a crude antioxidant extract. The antioxidant activity was evaluated using the linoleic acid peroxidation method and the free radical scavenging assays, namely 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals. Cortex fraxini extract (CFE) showed high inhibition of peroxidation of linoleic acid when compared with butylated hydroxytoluene (BHT). CFE also exhibited excellent scavenging activity on DPPH and hydroxyl radicals. Total antioxidant activity was measured by the reduction of Mo(VI) to Mo(V) by the extract, and subsequent formation of a green phosphate/Mo(V) complex at acid pH. CFE had significant total antioxidant activity and the effects were increased with increasing reaction time. The total phenolic content of the sample, analyzed by using Folin–Ciocalteu’s reagent, was 91.33 mg/g dry weight expressed as pyrocatechol equivalents. Then the suitability of CFE as an antioxidant was determined in peanut oil, and the decrease of lipid oxidation was monitored using thiobarbituric acid-reactive substances (TBARS) assay. CFE treatment significantly (P < 0.05) reduced lipid oxidation in peanut oil compared to the control. No significant differences (P = 0.05) in lipid oxidation were detected between CFE antioxidant and BHT antioxidant samples.