Comparative study of six pear cultivars in terms of their phenolic and vitamin C contents and antioxidant capacity

The main phenolic compounds in six pear cultivars were identified and quantified using high‐performance liquid chromatography/diode array detection (HPLC/DAD) and HPLC/electrospray ionisation mass spectrometry (HPLC/ESIMS). Major quantitative differences were found in the phenolic profiles. The peel contained higher concentrations of chlorogenic acid, flavonols and arbutin than the flesh, where only chlorogenic acid was detected. Total phenolics ranged from 1235 to 2005 mg kg^?1 in the peel and from 28 to 81 mg k g^?1 in the flesh. Ascorbic acid and dehydroascorbic acid were detected in the peel, whereas only dehydroascorbic acid was present in the flesh. The ranges of vitamin C content were from 116 to 228 mg kg^?1 in the peel and from 28 to 53 mg kg^?1 in the flesh. The antioxidant capacity was correlated with the content of chlorogenic acid (r = 0.46), while ascorbic acid made only a small contribution to the total antioxidant capacity of the fruit. Copyright © 2003 Society of Chemical Industry     

Antioxidant properties of various solvent extracts of potato peel,sugar beet pulp and sesame cake

BACKGROUND: Growing interest in the replacement of synthetic food antioxidants by natural ones has fostered research on vegetable sources and screening of raw materials to identify new antioxidants. The food‐processing industry generates substantial quantities of phenolic‐rich by‐products that could be valuable natural sources of antioxidants. In this study the antioxidant properties and total phenolic, flavonoid and flavonol contents of three industrial by‐products, sugar beet pulp, sesame cake and potato peel, extracted with various solvents were examined. Since different antioxidant compounds have different mechanisms of action, several methods were used to assess the antioxidant efficacy of extracts. RESULTS: Among the six solvents tested, methanol gave the highest extract yield of potato peel and sugar beet pulp, while diethyl ether gave the highest extract yield of sesame cake. Methanol exhibited the highest extraction ability for phenolic compounds, with total phenolics amounting to 2.91, 1.79 and 0.81 mg gallic acid equivalent g^?1 dry weight in potato peel, sugar beet pulp and sesame cake extracts respectively, and also showed the strongest antioxidant capacity in the three assays used. All three methods proved that potato peel extract had the highest antioxidant activity owing to its high content of phenolic compounds and flavonoids. CONCLUSION: On the basis of the results obtained, potato peel, sugar beet pulp and sesame cake extracts could serve as natural antioxidants owing to their significant antioxidant activity. Therefore they could be used as preservative ingredients in the food and/or pharmaceutical industries. Copyright © 2009 Society of Chemical Industry     

‘Limoncella’ apple,an Italian apple cultivar: Phenolic and flavonoid contents and antioxidant activity

‘Limoncella’ is a variety of apple traditionally cultivated in south-central Italy since ancient Roman times. The relationship between phenolic composition and antioxidant activity of apple peel and flesh was investigated. Apple extracts analysed by high-performance liquid chromatography, showed that compared with flesh, peel was richer in all the quantified phenols. The most abundant polyphenols were the flavanols catechin and epicatechin, and the chalcones phloridzin and phloretin xyloglucoside.     

Analysis of Phenolic Composition of Noble Muscadine (Vitis rotundifolia) by HPLC‐MS and the Relationship to Its Antioxidant Capacity

Abstract: Phenolic compounds and anthocyanins in muscadines have attracted much attention due to their diverse biological activities. With bioassays of antioxidant activities in terms of total phenolic content (TPC), total anthocyanin content (TAC), total procyanidin content (TPA), oxygen radical absorbance capacity (ORAC), and ferric reducing antioxidant power (FRAP) of different parts of the Noble muscadine, the butanol (BuOH) extract of the muscadine skin showed the highest TPC (317.91 ± 1.83 mg GAE/100 g FW), which might be ascribed to its high TAC of 227.06 ± 1.29 mg/100 g fresh weight (FW). The ethyl acetate (EtOAc) extract of the muscadine seed contained the highest TPA (55.30 ± 0.63 mg CE/100 g FW). Correlation analyses demonstrated a significant linear relationship of TPC and TAC compared to their ORAC and FRAP values within the range of R² from 0.9283 to 0.9936, which suggested that phenolics and anthocyanins in the extracts contributed significantly to their antioxidant potential. Nineteen individual phenolics and 5 anthocyanins were identified by HPLC‐MS, which indicated different chemical profiles of anthocyanins and other phenolics in the muscadine extracts. Practical Application: The paper has provided rich information of bioactive phytochemical profiles in different solvent extracts and their correlation with the antioxidant activity in the muscadine that is a very special regional fruit in U.S. Its high content of phenolic compounds demonstrates that muscadine could be beneficial to human health.     

Phenolic compounds in some apple (Malus domestica Borkh) cultivars of organic and integrated production

Eleven organically grown apple cultivars and 11 apple cultivars of integrated production from Austria and Slovenia were analyzed by HPLC for the content of phenolic compounds in peel and pulp. We identified chlorogenic acid, p‐coumaric acid, procyanidin B3, protocatechuic acid, (?)‐epicatechin, phloridzin, rutin and quercetin‐3‐rhamnoside in apple peel. In apple pulp, (+)‐catechin was also identified in all the cultivars. Some other phenols (procyanidin B3, rutin and quercetin‐3‐rhamnoside) could not be identified or were not properly separated. With regard to the phenolic content in the apple peel, there were no differences between organically grown apple cultivars and apple cultivars of integrated production. Organically grown apples, however, exhibited a higher content of phenolic substances in the apple pulp compared with the apple cultivars of integrated production. This may be due either to the different genotype source or to the growing technology. Higher concentrations of phenolic compounds in organically grown cultivars could be a result of plant response to stress. The apple peel contained higher concentrations of identified phenols than the pulp. The apple peel represents up to 10% of the whole fruit; therefore the phenolsic compounds in the pulp are of greater importance to the consumer than the phenolic compounds in the peel. Copyright © 2005 Society of Chemical Industry     

不同品种李子多酚组成及抗氧化活性

为研究不同品种李子果皮、果肉多酚组成及抗氧化活性,以9个不同品种的李子(芙蓉李、巫山李、玫瑰李、红布李、黑布李、西梅李、脆红李、江安李、青李)为原料,提取游离酚和结合酚,测定其1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力和抗氧化能力(oxygen radical absorbance capacity,ORAC)值,并通过高效液相色谱分析其多酚组成。结果显示:9种李子果皮总酚含量范围为111.52~775.88 mg GAE/100 g;果肉总酚含量范围为120.65~301.91 mg GAE/100 g,其中红布李果皮、果肉总酚含量均最高,西梅李总酚含量均最低。在多酚组成上,游离酚含量显著高于结合酚,且多酚组分主要为酚酸(原儿茶酸、绿原酸、咖啡酸)。体外抗氧化结果显示:9种李子果皮、果肉多酚均具有一定的抗氧化活性,DPPH自由基清除IC50值范围为4.38~46.46μg/m L,ORAC值范围为0.24~210.50μmol TE/g,其中巫山李果肉游离酚对DPPH自由基的清除能力最强,红布李果皮游离酚ORAC值最高。     

Flavonoid and chlorogenic acid profiles of English cider apples

The phenolics in 20 apple cultivars comprising 19 English cider apple varieties and one dessert apple variety were analysed by high‐performance liquid chromatography/tandem mass spectrometry. The cider varieties contained higher levels than the dessert apple and the peel was richer in phenolics than the flesh. The phenolic concentrations ranged between 230 and 4920 mg kg^?1 fresh weight in the flesh and between 546 and 6306 mg kg^?1 fresh weight in the peel. Fifteen compounds from five different phenolic groups, flavan‐3‐ols, flavonols, anthocyanins, hydroxycinnamates and dihydrochalcones, were detected. The major components in the flesh were 5‐O‐caffeoylquinic acid, procyanidin B2 and (?)‐epicatechin, while (?)‐epicatechin and quercetin glycosides predominated in the peel. Copyright © 2007 Society of Chemical Industry     

八种水果多酚的定量分析与抗氧化活性研究

本文对比研究了8种水果的果皮、果肉、果汁及全果中维生素C与总酚含量,采用高效液相色谱法测定其多酚种类及含量,并评价其抗氧化活性。8种水果Vc含量从高到低,依次为:番石榴脐橙菠萝=木瓜青苹果=皇冠梨=金桔=芒果;总酚含量最高的水果为芒果;从8种水果中共鉴定出16种多酚类化合物,以绿原酸、儿茶素、表儿茶素、芦丁、杨梅酮和根皮苷含量较高。根据8种水果全果中多酚物质种类与含量,分为4类:(1)脐橙;(2)芒果;(3)金桔;(4)青苹果、皇冠梨、番石榴、菠萝和木瓜;DPPH自由基清除能力从强到弱,依次为芒果番石榴青苹果皇冠梨=金桔=脐橙=菠萝=木瓜;氧自由基吸收能力从强到弱,依次为脐橙番石榴皇冠梨=芒果青苹果=金桔=菠萝=木瓜。本研究可为水果精深加工及功能性食品开发提供理论指导。     

Monomeric phenolics in different parts of high‐acid apple (Malus sieversii f. niedzwetzkyana (Dieck) Langenf): a promising source of antioxidants for application in nutraceuticals

The high‐acid apple (Malus sieversii f. niedzwetzkyana (Dieck) Langenf) possessing deep red peel and light red flesh is widely distributed in China. To determine if a useful apple variety is being ignored, the monomeric phenolic profiles and antioxidant activities of peel, flesh, pomace, whole fruit and juice were evaluated. The results were compared to those of ‘Fuji’ and ‘Granny Smith’ apples. The high‐acid apple possessing the highest total phenolic and anthocyanin contents among three apple varieties contained the most chlorogenic acid, phloridzin, epicatechin, ferulic acid, catechin, vanillic acid, p‐coumaric acid and caffeic acid. The extraction yields of phenolics (64%) and anthocyanins (89%) from the high‐acid apple to juice were the highest. The high‐acid apple possessing the greatest antioxidant activity had the strongest antihaemolysis activity, indicating that it could be used to produce juice and value‐added ingredient to assist in the prevention of chronic disease.     

Phenolic Profiles and Antioxidant Properties of Apple Skin Extracts

ABSTRACT:  Lipid oxidation, especially the oxidation of polyunsaturated fatty acids, is a significant issue in the food industry impacting both food quality and health of consumers. Apple skin was investigated as a source of natural antioxidants. The phenolic compound composition and antioxidant properties of 21 selected apple genotypes were evaluated. The lipid stabilizing ability of the apple skin extracts was examined using an aqueous emulsion system of methyl linolenate. The total phenolic concentrations determined by high-performance liquid chromatography tandem mass spectrometry of methanolic extracts of skins of the apple genotypes varied from 150 to 700 mg/100 g DW. The antioxidant capacity measured by Folin–Ciocalteu (16.2 to 34.1 mg GAE/100 g DW), ferric reducing antioxidant power (1.3 to 3.3 g TE/100 g DW), oxygen radical absorbance capacity (5.2 to 14.2 g TE/100 g DW), and percent inhibition of oxidation of methyl linolenate (73.8% to 97.2%) varied among the apple genotypes. The apple skin extracts, specifically the crab apple varieties such as "Dolgo," were revealed to be effective inhibitors of oxidation of polyunsaturated fatty acid in a model system and thus can be considered as a potential source of natural food antioxidants.     

The effect of postharvest 1-MCP treatment and storage atmosphere on ‘Cripps Pink’ apple phenolics and antioxidant activity

This study investigated the effect of a postharvest 1-methylcyclopropene (1-MCP) treatment, controlled atmosphere and storage time on the total antioxidant activity (TAA) and phenolic compounds in the peel and flesh of ‘Cripps Pink’ apples (Malus domestica Borkh.). Preclimacteric apples were harvested and treated with 1-MCP then stored in normal atmosphere (NA) or controlled atmosphere (CA) at 0 °C for up to 160 days. In general, the level of phenolics decreased by 9% in the peel and significantly increased twofold in the flesh during cold storage, regardless of storage atmosphere or 1-MCP treatment. However, treatment with 1-MCP resulted in significantly lower concentrations of chlorogenic acid and procyanidin B2 in apple flesh, and catechin and epicatechin in the peel compared to the control fruits. There was no significant effect of CA on the phenolic compounds during long-term storage, except for quercetin 3-galactoside and quercetin 3-glucoside, which both significantly increased under CA storage. Total antioxidant activity (TAA) is an important nutritional attribute of apples in the human diet. The results showed that TAA in the peel tissue was about eight times higher than that of the flesh, with mean values of 4.75 g TE/kg FW and 0.56 TE/kg FW, respectively. The TAA in both the peel and flesh tissue increased significantly during storage by 40% and 70%, respectively. The storage atmosphere did not significantly affect TAA in either the peel or flesh, whilst the 1-MCP treatment significantly reduced the TAA in the peel tissue only. These results show the beneficial combined effects of pre-storage 1-MCP treatment and CA on ‘Cripps Pink’ apple phenolic composition and antioxidant capacity during long term storage.     

Phenolic content and antioxidant activities of selected potato varieties and their processing by-products

The total content of free, esterified and bound phenolics of the peel and flesh of four potato varieties (Purple, Innovator, Russet and Yellow) were determined using the Folin–Ciocalteu method. The respective antioxidant activities of these potatoes and/or their skins were evaluated using several in vitro assays. The phenolic profiles of potato peel and flesh samples were determined using high-performance liquid chromatography with photodiode array detection (HPLC-DAD). Bound and esterified phenolics contributed as much or even more than the free phenolics to the antioxidant activity of the peels; extracts from Purple variety showing the highest activity. The peels of all varieties showed significantly (p < 0.05) higher phenolic content and antioxidant activities than their respective flesh. Chromatographic data showed differences in the amounts, but not in types, of phenolic compounds in the potato peel samples. Thus, potato processing discard may be used in food formulations and their extracts could potentially be employed as an effective source of antioxidants in food systems.     

不同品种梨果实酚类物质和抗氧化性能分析

以我国北方11 个主栽梨品种黄冠、绿宝石、雪梨、鸭梨、丰水、南水、圆黄、黄金、华山、五九香和早酥的果实为试材,分别测定了果皮、果心和果肉中可溶性酚的含量,并对酚类物质进行了高效液相色谱（highperformance liquid chromatography,HPLC）分析。通过分别测定果皮、果肉、果心的乙醇提取液对DPPH自由基和羟自由基的清除能力,对其所含酚类物质的抗氧化性能进行了评价。结果表明：1）梨果心酚类物质含量高于果皮,果肉最低;2）在果心和果皮中均检测出熊果苷、没食子酸、儿茶素、绿原酸、咖啡酸、表儿茶素、香豆酸和芦丁8 种酚类物质,而在果肉中检测出熊果苷、没食子酸、绿原酸、表儿茶素和芦丁5 种物质;3）熊果苷、绿原酸和表儿茶素都为果肉和果皮的主要酚类物质,果肉中绿原酸的含量高于熊果苷,果皮则反之,果心所含酚类物质以绿原酸和熊果苷为主,且绿原酸的含量高于熊果苷;4）果皮、果肉、果心不同部位的酚类物质的含量与1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力和羟自由基清除能力间均分别呈显著正相关关系,表明酚类物质与自由基清除能力的关系密切。     

Determination of antioxidant activity and phenolic compounds of Muntingia calabura Linn. peel by HPLC‐DAD and UPLC‐ESI‐MS/MS

Antioxidant activity in Muntingia calabura Linn. peel was evaluated by DPPH radical, ORAC, ABTS cation radical, FRAP assays and total phenolic contents by different extraction conditions. In addition, a method for determination of phenolic compounds in calabura peel samples harvested in Brazil using methanol:water and magnetic stirring as the extraction method, HPLC‐DAD and UPLC‐ESI‐MS/MS analysis were developed. Calabura peel showed antioxidant activity for all extraction conditions and assays evaluated, the most polar solvents being more effective. The developed HPLC‐DAD method allowed the accurate determination of phenolic compounds, with recoveries in the range of 72–107% and precision values ≤4%, with exception for chlorogenic acid. Gallic acid was determined at the highest concentration levels, followed by myricetin, ferulic acid and vanillic acid. However, all the five proposed phenolic compounds were identified in calabura peel samples by UPLC‐ESI‐MS/MS. Thus, calabura peel, an uncommon edible fruit part, can be appointed as a rich source of phenolic compounds.     

不同品种苹果果实主要酚类物质含量的研究

用高效液相色谱仪测定了不同品种苹果果实绿原酸、儿茶素、表儿茶素、根皮素和槲皮素等主要酚类物质的含量。结果表明,不同品种苹果果肉酚类物质总量以富士和新红星最高,金冠最低。富士苹果果肉酚类物质以绿原酸为主,新红星和王林苹果果肉以表儿茶素为主。不同品种苹果果皮酚类物质总量以新红星最高,各品种苹果果皮酚类物质总量均高于果肉。果皮中酚类物质以黄烷-3-醇类为主。     

The phenolic composition and antioxidant capacity of soluble and bound extracts in selected dietary spices and medicinal herbs

Phenolic compounds, commonly found in plant‐based foods, exist in free or bound form. Despite much research on the soluble phenolics in spices and herbs, their bound phenolics have not been intensively investigated. In this study, six common dietary spices and medicinal herbs (Padang cassia, oregano, clove, Chinese cassia, Japanese knotweed and peel of pomegranate) were selected to evaluate and compare their phenolic composition and antioxidant capacity in soluble extracts (SEs) and bound extracts (BEs). Generally, the samples had high total phenolic content and antioxidant capacity, with lower levels in the BEs. From the HPLC results, (+)‐catechin, (?)‐epicatechin, eugenol, cinnamaldehyde and carvacrol were the major phenolic compounds in the SEs, and gallic acid, p‐coumaric acid and ellagic acid in the BEs. Phenolic compounds are likely the major contributors to the antioxidant capacity of these plant samples. Overall, these dietary spices and medicinal herbs can be excellent sources of natural antioxidant phenolics.     

不同品种苹果籽总酚含量与抗氧化相关性研究

为探讨苹果籽总酚含量与抗氧化相关性及其抗氧化的物质基础,以7 个品种苹果籽为材料,采用 Folin-Ciocalteu法测定总酚含量,FRAP法、ABTS＋·法、O2－·清除法、·OH清除法和DPPH自由基清除法评价抗氧化活性,高效液相色谱法进行多酚成分分析。结果表明：7 个品种苹果籽总酚含量范围为5.74～17.44 mg GAE/g（以干质量计）,抗氧化性优于茶多酚、VC和2,6-二叔丁基-4-甲基苯酚（2,6-di-tert-butyl-4-methylphenol,BHT）,蜜脆苹果籽具有最高的总酚含量和最好的抗氧化能力。除DPPH自由基清除法外,多酚含量与其他4 种方法测得的抗氧化数据具有显著正相关（r=0.771～0.984）。根皮苷为苹果籽多酚抗氧化的主要成分。     

Chemical Components and Antioxidant Activity of the Peels of Commercial Apple‐Shaped Pear (Fruit of Pyrus pyrifolia cv. pingguoli)

Abstract: The apple‐shaped pear, the fruit of the Pyrus pyrifolia cv. pingguoli (Rosaceae) tree, is one of the most popular fruits in the northern part of China. The current study is the 1st report of its bioactive components. We identified 10 metabolites from the peels (exocarp) of apple‐shaped pear and assessed their toxicity. We then compared the anti‐oxidant activity, amount of total phenolic compounds, and total condensed tannin content of the peels and flesh (mesocarp) of apple‐shaped pear. The 6 major components in the peels and flesh of this fruit were quantified with Ultra Performance Liquid Chromatography–Electrospray Ionization Mass Spectrometry. Results revealed that the peels possessed stronger anti‐oxidant activity and contained larger amounts of phenolic compounds than the flesh. These results provide insights into the potential health benefits of this fruit and support the use of the fruit peels and products containing peels or peel components. Practical Application: The present research provided evidences that the pulp and peel waste from the juice industry of apple‐shaped pear may be a source of useful compounds.     

Total antioxidant capacity and content of flavonoids and other phenolic compounds in canihua (Chenopodium pallidicaule): an Andean pseudocereal

Total antioxidant capacity (TAC), total phenolic compounds (TPH), total flavonoids (TF) and individual phenolic compounds were determined in canihua collected at approx. 3850 m altitude. The TAC values varied among samples from 2.7 to 44.7 by the ferric reducing antioxidant power (FRAP) method and from 1.8 to 41 by the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method expressed as micromol of Trolox equivalents/g dw. The content of TPH was 12.4-71.2 micromol gallic acid equivalents/g dw and that of the TF ranged between 2.2 and 11.4 micromol of catechin equivalents/g dw. The data obtained by the four methods showed several significant correlations. Prior to analysis by HPLC, the samples were subjected to acid hydrolysis and in the water-soluble extracts this led to an up to 20-fold increase in the TAC values in comparison with the values of the nonhydrolysed samples. HPLC analysis showed the presence of eight major compounds identified as catechin gallate, catechin, vanillic acid, kaempferol, ferulic acid, quercetin, resorcinol and 4-methylresorcinol. Their estimated contribution to the TAC value (FRAP method) indicated that resorcinols contributed most of the antioxidant capacity of the water-soluble extract. The results show that canihua is a potential source of natural antioxidant compounds and other bioactive compounds which can be important for human health.     

Phenolic Profiles,Antioxidant Activities,and Neuroprotective Properties of Mulberry (Morus atropurpurea Roxb.) Fruit Extracts from Different Ripening Stages

The present work investigated the phenolic profiles (including nonanthocyanin and anthocyanin phenolics), antioxidant activities, and neuroprotective potential of mulberry fruit (MF) (Morus atropurpurea Roxb.) grown in China at different ripening stages. High‐performance liquid chromatography‐tandem mass spectrometry method (HPLC‐MS/MS) was used to identify and quantify the phenolic compounds. The antioxidant capacity, total phenolic content (TPC), total flavonoid content (TFC), and total monomeric anthocyanin content (TAC) were determined using spectrophotometric methods. The neuroprotective effects of MFs at different ripening stages were investigated using Aβ_25‐35‐treated PC12 cells as the cellular model of Alzheimer's disease. Of the 19 phenolic compounds characterized from the MF extracts, the contents of rutin and anthocyanins increased and that of chlorogenic acid decreased significantly with maturity. At the fully ripened stage, MF extracts showed the highest amounts of TPC (11.23 mg gallic acid equivalents/g fresh weight), TFC (15.1 mg rutin equivalents/g fresh weight), and TAC (1177 mg cyanidin 3‐O‐glucoside equivalents/100 g fresh weight). Meanwhile, antioxidant activity of MF extracts at this stage was highest according to ABTS (an IC50 value of 4.11 μg/mL) and DPPH (an IC50 value of 10.08 μg/mL) assays. Cellular assays revealed increased cell viability in cells treated with the ripe MF extracts; compared with the control groups, the ripening fruits also increased the antioxidant enzyme levels in PC12 cells. Together, these results suggest that the antioxidant activities and neuroprotective properties of ripening MFs are related to the contents and types of phenolic compounds that are present in the fruits.