LIPIDS OF WHEAT, CORN AND POTATO STARCH

The lipid constituents from wheat, corn and potato starches were analyzed, as was the composition of nonstarch compounds present in these lipid extracts. The lipids were extracted from starch granules using n- propanol-water (3:1, v/v) via cold and hot extraction into surface and internal lipid fractions, respectively; fatty acid profiles of the fractions so obtained were then carried out. The content of surface lipids was greatest from potato and wheat starches, whereas cornstarch was characterized as having the highest relative percentage of internal lipids. Hot extraction resulted in an increase in the lipid content for all extracts, and of the starches investigated, the lipids from cornstarch contained the highest percentage of polyunsaturated fatty acids. Unlike that of wheat starch, it was noted that the fatty acid, C20: 1 (n-9), could only be extracted from corn and potato starch granules by the hot extraction technique. Lysophosphatidylcholine (LPC) and some phenolics were found to bind to wheat starch granules, but not to those of corn and potato. Using HPLC-UV-DAD analysis, five phenolic compounds were detected in the lipids extracted from wheat starch by hot extraction. Maxima from UV-DAD spectra of the compounds were observed at a wavelength of 337.4 or 332.7 nm, and are characteristic of phenolic acids or their derivatives.     

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.     

蔬菜及其制品中不同形态酚酸成分分析

采用超高效液相色谱-串联质谱法对10?种蔬菜及其制品,包括豇豆、西兰花、黄豆芽、茄子、番茄、黄瓜、菠菜、白菜、马铃薯和番茄酱中的游离型、游离酯型和结合型酚酸进行测定和分析。结果表明不同种类蔬菜酚酸含量差异较大,游离型酚酸以白菜中含量最高;游离酯型酚酸在豇豆中含量最高,其次是菠菜;结合型酚酸在菠菜中含量最高。主成分分析表明,对香豆酸是豇豆中的特征性物质,阿魏酸和异阿魏酸是菠菜区别于其他种类蔬菜的特征性组分,而芥子酸是白菜中的特征性物质。本研究可以为蔬菜中功能性成分的开发利用提供有益参考。     

Effects of drying temperature on the flavonoid,phenolic acid and antioxidative capacities of the methanol extract of citrus fruit (Citrus sinensis (L.) Osbeck) peels

There are many active functional compounds in citrus peels, such as flavonoid and phenolic acid. Scientists tried to obtain more bioactive components from citrus peels by various methods. This research investigated the effects of different drying temperatures (50, 60, 70, 80, 90 and 100 °C) on changes in the flavonoid, phenolic acid and antioxidative activities of citrus fruit (Citrus sinensis (L.) Osbeck) peels. The total phenolic and flavonoid contents of drying treated orange peels were decreased by lower drying temperature (50 and 60 °C) and increased by higher drying temperature (70, 80, 90 and 100 °C). Amounts of phenolic compounds in the 100 °C treated sample extract were significantly higher than the amounts in the samples heated at other temperatures (P < 0.05). EC₅₀ values of orange peel extracts by DPPH radical scavenging effects and ABTS^·+ scavenging effects were increased with lower drying temperature and decreased with higher drying temperature, and the values of 100 °C treated sample extract were significantly lower than the samples heated at other temperatures (P < 0.05). However, the chelating Fe^{2 +} activities of samples showed the opposite trend.     

Ultrasound‐assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

Ultrasound‐assisted extraction (UAE) at 33 and 42 kHz has been investigated in the extraction of polyphenols from peels of two potato varieties, cream‐skinned Lady Claire (LC) and pink‐skinned Lady Rosetta (LR), commonly used in snack food production. Extraction efficacy between the UAE‐untreated (control) and the UAE‐treated extracts was assessed on the total phenolic content and antioxidant capacities (DPPH and FRAP). Application of UAE showed significantly higher recovery of phenolic compounds compared to solid–liquid extraction process alone. Lower ultrasonic frequency (33 kHz) was more effective in recovering polyphenols compared to 42 kHz ultrasonic treatment. The liquid chromatography‐tandem mass spectrometry revealed that chlorogenic acid and caffeic acid were the most prevalent phenolics in LR peels, whereas caffeic acid was dominant in LC peels. Peleg's equation showed a good correlation (R² > 0.92) between the experimental values and the predicted values on the kinetics of UAE of phenolic compounds.     

UPLC-MS/MS同时测定铁皮石斛茎、叶、花中酚类组分的含量

建立超高效液相色谱-串联质谱同时、快速分析18 种酚类物质的方法,测定比较铁皮石斛茎、叶、花部位含量差异。样品用甲醇-水溶液提取,提取液中的目标化合物经Waters T3 C18柱梯度洗脱分离,电喷雾串联三重四极杆质谱仪正、负离子扫描方式多反应监测模式检测。结果表明：以18 种酚类物质标准品作为对照,在铁皮石斛样品中共检出15 种酚类组分,分别为3,5-二羟基苯甲酸、橘皮素、绿原酸、槲皮素、芦丁、对羟基苯甲酸、咖啡酸、丁香酸、香草酸、山柰酚、对香豆酸、芥子酸、阿魏酸、3-羟基肉桂酸、水杨酸。铁皮石斛不同部位多酚组分含量为花＞叶＞茎,相对于其他酚类组分,芦丁在铁皮石斛茎、叶、花中的含量均为最高。铁皮石斛不同部位主要酚类组分表现出一定的差别：铁皮石斛花中主要含有芦丁、咖啡酸、阿魏酸和对羟基苯甲酸,铁皮石斛叶中芦丁和阿魏酸的含量相对较高,而铁皮石斛茎部主要酚类组分则为芦丁、阿魏酸与香草酸。实验结果可为铁皮石斛不同部位酚类组分的利用提供一定的科学依据。     

Minerals, phenolic compounds, and antioxidant capacity of citrus peel extract by hot water

ABSTRACT:  Some dried citrus peels, more familiar as chenpi in China, have been widely used in traditional Chinese medicines from ancient times. This paper reports the efficiency of infusion cooking on extracting minerals and phenolic compounds (flavanone glycosides [FGs], polymethoxylated flavones [PMFs], and phenolic acids), and also antioxidant activity of hot water extract of citrus peels. Peels of 2 citrus varieties, namely, Satsuma mandarin ( C. unshiu Marc.) and Ponkan ( C. poonensis Hort. ex Tanaka), which belong to C. reticulata , were selected. As a result, hot water extraction was efficient in extracting phenolic acids and some minerals. As for citrus flavonoids, narirutin, nobiletin, and tangeretin were easier to extract than hesperidin. The result of antioxidant capacity assays indicated that for citrus peels, hot water extract had almost the same capacity as the methanol extract. We suggested that Ponkan was more suitable as the source of chenpi , since its hot water extract had much higher content of phenolic acids, FGs and PMFs, and higher antioxidant capacity than those of Satsuma mandarin. Generally, to raise the extraction temperature or to prolong the time could not yield higher content of phenolic compounds and stronger antioxidant capacity, though the content of minerals increased to some extent. Furthermore, a 2nd-time extraction seemed necessary since considerable minerals and phenolic compounds could be obtained by doing so. Finally, we suggested that 2 times extraction at 100 °C for 30 min was proper to extract the minerals and phenolic compounds in chenpi .     

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.     

Utilization of mango peels as a source of pectin and polyphenolics

Two different options for the combined recovery of pectin and phenolic compounds from mango peels, a byproduct of industrial mango processing, were developed. After extraction of dried mango peels with diluted sulfuric acid, the phenolic compounds were adsorbed using a styrene–divinylbenzene copolymerisate resin, and pectin was obtained from the effluent by precipitation with ethanol. Phenolic compounds were recovered from the resin with methanol and the eluate was lyophilized (Process I). Alternatively, the pectin was precipitated by adding the crude extract to ethanol. After removal of the organic solvent, the phenolic compounds were obtained from the aqueous phase of the precipitation bath using the adsorbent resin as described before (Process II). While in total, 129.4 mg/g polyphenols were detected in the lyophilizate obtained from Process I, only 71.0 mg/g dm could be recoverd from Process II. The profiles of the polyphenols were almost identical, revealing that during pectin precipitation preferential adsorption of polyphenolic compounds to the pectin may be excluded. Besides the characterization of the pectins and the phenolic compounds, investigations into the influence of the drying temperature on the polyphenolic content of the peels were carried out, indicating a significant loss of flavonol glycosides depending on heat exposure. On the other hand, some xanthone glycosides were formed during the drying process. Furthermore, antioxidative capacities of the lyophilized eluates were investigated using the DPPH, TEAC and FRAP assays. The antioxidative capacity of the extracts exceeded that of mangiferin and quercetin 3-O-glucoside, respectively, thus demonstrating mango peels to be a suitable source of health-beneficial compounds. The lyophilizates obtained from Process I showed higher antioxidative capacities in all three assays. These findings indicate a correlation between the amount of phenolic compounds and the antioxidative capacity.

Industrial relevance

Byproducts of mango processing amount to 35–60% of the total fruit weight. Their complete exploitation for further product recovery is a promising measure from both an environmental and economic point of view. In our previous study mango peels were found to be a rich source of pectin, with a high degree of esterification and phenolic compounds, like flavonol O- and xanthone C-glycosides. Therefore, two alternative processes for the combined recovery of pectin and polyphenols, which can easily be integrated in an existing pectin production process, were developed in the present study.     

Preparation of free, soluble conjugate, and insoluble-bound phenolic compounds from peels of rambutan (Nephelium lappaceum) and evaluation of antioxidant activities in vitro

The soluble phenolic compounds of rambutan peels (RP) were extracted by microwave-assisted extraction (MAE) and the operating parameters were optimized. The optimal conditions obtained were ethanol concentration of 80.85%, extraction time of 58.39 s, and the ratio of liquid to solid of 24.51:1. The soluble phenolic content by MAE was 213.76 mg GAE/g DW. The free, soluble conjugate, and insoluble-boaund phenolic compounds were prepared by alkaline hydrolysis, and the contents of 3 fractions were 185.12, 27.98 and 9.37 mg GAE/g DW, respectively. The contents of syringic acid and p-coumaric acid were high in the free fraction, showing 16.86 and 19.44 mg/g DW, and the soluble conjugate and insoluble-bound phenolics were mainly composed of gallic acid and caffeic acid. Furthermore, the antioxidant activities of 3 fractions were evaluated in 5 model systems. Results indicated that the free fraction had high antioxidant activities, compared with the soluble conjugate and insoluble-bound fractions.     

Antioxidant capacities,procyanidins and pigments in avocados of different strains and cultivars

Avocado (Persea americana) is an important tropical fruit, but little is known about their antioxidant capacities and phytochemical composition. The objective of this research was to determine antioxidant capacities, total phenolic content and identify and quantify major antioxidant compounds in avocados of different strains and cultivars. Ripe Florida avocados from seven cultivars (Slimcado, Booth 7, Booth 8, Choquette, Loretta, Simmonds, and Tonnage) of West Indian or Guatemalan strains were separated into seeds, peels and pulp, and freeze dried. Hass avocado of Mexican strain was chosen for comparison. Samples were extracted with acetone/water/acetic acid solvent and analysed using the Folin–Ciocalteu assay for total phenolic content. Antioxidant capacities were determined by oxygen radical absorbance capacity (ORAC) and DPPH assays. Procyanidins were identified and quantified using HPLC-MSⁿ. Antioxidant pigments (chlorophylls and carotenoids) were estimated spectrophotometrically. For all varieties, seeds contained the highest antioxidant capacities, phenolic content, and procyanidins, whereas the pulp had the lowest. Procyanidins, including catechin, epicatechin, A- and B-type dimers, A- and B-type trimers, tetramers, pentamers and hexamers, were identified in peels and seeds using normal-phase HPLC–ESI-MSⁿ. Antioxidant capacities, phenolic contents and procyanidins in avocados were highly correlated, suggesting that procyanidins were the major phenolic compounds that contributed to antioxidant capacities. Carotenoids and chlorophylls were found to be concentrated in avocado peels but did not correlate with antioxidant capacities. This study suggested that avocado seeds and peels, industrial wastes of avocado processing, can be exploited as source of antioxidants.     

甘薯及马铃薯提取物的抗氧化活性研究

用活性氧法（ＡＯＭ）及滤纸硫氰化铁新法研究了甘薯与马铃薯皮部与肉部提取物对大豆油的抗氧化活性。结果表明提取物具有很强的抗氧化活性。用简易的滤纸硫氰化铁法与酚试剂显色法初步考查显示，其有效成分含绿原酸、异绿原酸、４－Ｏ－咖啡酰奎尼酸和新绿原酸。各提取物分别含总酚０．５０～１３．８ｍｇ／ｇ提取物。     

椪柑、温州蜜桔果皮中酚类物质组成及抗氧化能力研究

目的:研究椪柑、温州蜜桔果皮中酚酸与黄烷酮糖苷组成及其抗氧化能力。方法:高效液相法测定椪柑、温州蜜桔果皮中九种酚酸和两种黄烷酮糖苷的组成与含量。用福林酚法、ABTS法和FRAP法对椪柑、温州蜜桔果皮甲醇提取液抗氧化能力进行评价。结果:柑橘果皮中可溶酯化酚酸部分所占比例最大,肉桂酸型酚酸是柑橘皮中的主要酚酸,且主要以酯化形式存在,其含量排列顺序一般为:阿魏酸>对香豆酸>芥子酸>咖啡酸。温州蜜桔果皮中有较高总酚酸含量(p<0.05)。椪柑果皮主要含橙皮苷,温州蜜桔果皮含橙皮苷和少量柚皮芸香苷。温州蜜桔果皮中总黄烷酮糖苷含量高于椪柑(p<0.05)。总的来说椪柑果皮提取液抗氧化活性略高于温州蜜桔。结论:HPLC测定柑橘皮中酚酸与黄烷酮糖苷可取得良好结果,抗氧化实验表明柑橘皮具有一定的抗氧化能力。     

HS-SPME和GC-MS联用法对甘薯醋挥发性香气成分的分析

采用顶空固相微萃取和气相色谱质谱联用技术分析了甘薯醋液中的挥发性香气成分。结果表明,从甘薯醋液中检测并鉴定出 49 种化合物。其中酸类9种（61.96%）、酯类9种（9.89%）、醇类9种（8.98%）、杂环类化合物11种（8.22%）、醛类2种（2.04%）、酚类1种（0.09%）、酮类4种（0.08%）及其他化合物4种（4.72%）。含量较高的乙酸和5-氨基颉草酸、2,3-丁二醇和乙醇、乙酸乙酯和L（-）-乳酸乙酯以及2,3,5,6-四甲基吡嗪是形成甘薯醋风味特征的主要物质。     

Dietary fibre components,antioxidant activities and hydration properties of ripe persimmon (Diospyros kaki L. cv. Daebong) peel powders as affected by different washing treatments

Dietary fibre components, hydration properties and antioxidant activities such as 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging, reducing power, metal chelating and 2,2′‐azino‐bis,3‐ethyl‐benzo‐thiazoline‐6‐sulphonic acid (ABTS) radical scavenging activities of persimmon peel powders using different washing treatments (tap water at 20 °C and hot water) were investigated. Peel powder obtained from hot water‐washed peels (74.95 g per 100 g) had higher dietary fibre content than tap water‐washed (65.50 g per 100 g) and unwashed (60.99 g per 100 g) peels. The higher content of total phenolic and ascorbic acid were found in peel powder obtained from unwashed peels, whereas washed peels had more β‐carotene content. The EC₅₀ values of scavenging DPPH and ABTS radical for peel powders obtained from unwashed, tap water‐washed and hot water‐washed peels were 75.44, 142.18 and 110.17 μg mL^?1 respectively and 5.31, 5.34 and 5.39 μg mL^?1 respectively. Therefore, hot water washing is recommended to obtain better quality products from persimmon peel for use as a fibre supplement.     

果皮中酚类物质含量、抗氧化活性及在体外消化过程中成分的变化

从21 种果皮中筛选出总酚、总黄酮含量较高的果皮,并选择1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基、2,2’-联氨-双-3-乙基苯并噻唑啉-6-磺酸（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS）阳离子自由基清除力评价其抗氧化活性。对筛选出酚类物质含量高且抗氧化活性强的果皮进行体外模拟胃肠液消化,研究不同消化时间对总酚、总黄酮释放量的影响,并通过透析袋模拟肠道的吸收作用,考察其生物利用率,同时利用超高效液相色谱-二极管阵列检测器/电喷雾飞行时间质谱（ultra performance liquid chromatography-diode array detector/electrospray ionization-time of fight-mass spectrometry,UPLC-DAD/ESI-TOF-MS）研究模拟胃肠液消化前后酚类物质变化。结果表明：21 种果皮中石榴皮（总酚含量为（58.09±0.46）mg/g、总黄酮含量为（47.50±0.39）mg/g）和山竹皮（总酚含量为（52.09±1.52）mg/g、总黄酮含量为（36.07±0.46）mg/g）中酚类物质含量较高;石榴皮的抗氧化能力强于山竹皮;模拟胃液消化阶段,石榴皮中总酚和总黄酮释放量均增加,模拟肠液消化阶段总酚和总黄酮的释放量先增加后减少;与胃液消化阶段相比,肠液消化阶段总酚和总黄酮含量明显降低;生物利用率测定结果表明总酚的生物利用率在每个时间点均强于总黄酮;通过UPLC-DAD/ESI-TOF-MS从石榴皮提取物中共检测出的5 种酚类化合物（分别为α-安石榴苷、β-安石榴苷、鞣花酸己糖苷、鞣花酸脱氧己糖苷、鞣花酸）,其在胃液消化过程中损失率小于肠液消化,说明石榴皮中酚类物质在酸性环境中结构稳定。     

苹果梨酚类物质抗氧化活性研究

通过对DPPH 自由基、羟自由基(·OH)和亚硝酸根离子的清除能力实验,测定苹果梨幼果和成熟果果皮中提取的酚类物质抗氧化活性。结果表明：苹果梨酚类物质对DPPH 自由基、·OH 和亚硝酸根离子均有较好的清除效果,其中幼果中提取的酚类物质清除效果要好于成熟果果皮。     

Antioxidant efficacy of potato peels and sugar beet pulp extracts in vegetable oils protection

The antioxidant properties of potato peels and sugar beet pulp, in comparison with synthetic antioxidant, were investigated. The bioactive materials were extracted with methanol and examined for their antioxidant activity under accelerated oxidation conditions, using sunflower and soybean oils as oxidation substrates at different concentrations for 72 h at 70 °C. Inverse relationships were noted between peroxide values and oxidative stabilities and also between secondary oxidation products, measured by p-anisidine value and stabilities at termination of the storage. Absorptivity at 232 nm and 270 nm increased gradually with the increase in time, due to the formation of conjugated dienes and polyenes. The order of oxidative stability was as follow: TBHQ > potato peels > BHT = sugar beet pulp > BHA. The predominant phenolic compounds identified by thin-layer chromatography in potato peels and sugar beet pulp were chlorogenic and gallic acids. The results of different antioxidant parameters demonstrated that potato peels and sugar beet pulp are potent sources of natural antioxidants that might be explored to prevent oxidation of vegetable oils.     

Investigation of the contents of phenolic and alkaloidal compounds of gamma irradiated potatoes during storage

The contents of phenolic cinnamic acids and coumarins as well as of the glycoalkaloids of gamma irradiated potato tubers have been studied in detail. Gamma irradiation up to 3 k Gy had no effect on the glycoalkaloid contents of two potato tuber varieties during a four months storage period. The phenolic compounds behave differently and show a considerable change during storage in potatoes irradiated at the highest dose level, 3 k Gy. A time dependent change of phenolic extracts was observed. This change of phenolic compounds could be partly ascribed to the β-glycoside of scopoletin (coumarin, 7-hydroxy-6-methoxy) and was accompanied by a general decrease of chlorogenic acid, the main hydroxy-cinnamic acid of potatoes.     

Effect of defatting and decortication on distribution of fatty acids,phenolic and antioxidant compounds in sorghum (Sorghum bicolor) bran fractions

Sorghum bran components could be a potential source of nutrients and phytochemicals for industrial applications. The effect of defatting with hexane and different degrees of decortication on distribution of fatty acids, phenolic compounds, colour (L, a and b) and antioxidant activity (DPPH) of red (RS) and white (WS) sorghums was studied. The decortication process was carried out at time intervals of 1–6 min. Defatted and nondefatted fractions were analysed. The content of polyunsaturated fatty acids (PUFA) was higher than monounsaturated fatty acids (MUFA); the content of MUFA was higher than saturated fatty acids (SFA). Linoleic, oleic and palmitic acids predominated in all fractions. Significant differences in the content of palmitic and linolenic acids between sorghums were found. RS had higher content of palmitic, and WS was higher in linoleic acid. Defatted samples contained lower amounts of phenolic compounds and higher antioxidant activities, than nondefatted samples. RS was a better source of total phenolic compounds and antioxidant activity compared with WS, but WS presented a more suitable profile of fatty acids. In conclusion, fractions of both types of sorghums can be used in cereal‐based products to enhance their phytochemical profile.