黑色dot_ring
Poachers have been netting salmon to supply the black market.
盗猎者一直在捕捞大麻哈鱼到黑市上去卖。
There is a plentiful supply of arms on the black market.
黑市上有大量武器出售。
I slowly zipped and locked the heavy black nylon bags.
我慢慢地把那些沉重的黑色尼龙袋的拉链拉上并锁好。
If Hardy had grown up on the Black Sea .
Pipe black eyes and mouth then leave to set.
Black Dice are a rock band who write songs.Phenolic and Tyrosyl Ring Deiodination of Iodothyronines in Rat Brain Homogenates
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淘豆网网友近日为您收集整理了关于Phenolic Profiles and Antioxidant Activity of Buckwheat （Fagopyrum esculentum MSench and Fagopyrum tartaricum L. Gaerth） Hulls, Brans and Flours的文档，希望对您的工作和学习有所帮助。以下是文档介绍：Phenolic Profiles and Antioxidant Activity of Buckwheat （Fagopyrum esculentum MSench and Fagopyrum tartaricum L. Gaerth） Hulls, Brans and Flours Available online atⅥ^^^Ⅳ. Phenolic Profiles and Antioxidant Activity of Buckwheat(Fagopyrum esculentum M6ench and Fagopyrum tartaricum L.Gaerth)Hulls,Brans and Flours LIFu—hua1,YUAN Ya ,YANG Xiao—lan ,TAO Shu—ying andM ING Jian , ,。 College of Food Science,Southwest University,Chongqing 400715 P.R.China 2Key Laboratory of Food Processing& Technology(来源：淘豆网[/p-7115411.html]) of Chongqing,Chongqing 400715,P.R.China Laboratory of Quality&Safety Risk Assessmentfo,Agro—Products on Storage and Presevation,,Mimnistry of Agriculture,Chongqing 400715,P.R.China Abstmct The extracts from hulls,brans and flours of Fagopyrum esculentum MOench(FEM,three varieties)and Fagopyrum tartaricum L.Gaerth(FTG,seven varieties)were screened for free and bound phenolic content or total phenolic content (TPC),as well as 1,1 diphenyl·2-(来源：淘豆网[/p-7115411.html])picryl hydrazyl(DPPH)free radical scavenging activity and reducing power.Free phenolics were predominant in buckwheat hulls,brans and flours.FEM hulls extract exhibited the highest reducing power and DPPH free radical scavenging activity with the average EC50 84.54 g mL一1 and IC50 1 1.54
g mL~respectively,FTG brans extract had the highest average TPC(24.87 mg GAE g-1 DW),and FEM flours extract showed the lowest TPC,reducing power and radical scaven(来源：淘豆网[/p-7115411.html])ging activity.Furthermore,the correlations among TPC,DPPH free radical scavenging activity and reducing power of all the sam ples were investigated.The rank correlation coefficient( )between reducing power and DPPH free radical scavenging activity of buckwheat hulls,between TPC and DPPH flee radical scavenging activity of buckwheat flours were 0.76 and 0.79,respectively(P&0.05).However,there is no significant correlation betw een the remaining in(来源：淘豆网[/p-7115411.html])dexes of hulls and flours,as well as the ten buckwheat brans.This result indicated that some non—pounds also contributed to the total antioxidant activity in hulls,brans and flours of buckwhe￣s.This study demonstrated that buckw heat hulls and brans,rather than flours,are good source of antioxidants. Key words:Fagopyrum esculentum MOench,Fagopyrum tartaricum L.Gaerth,phenolic content,antioxidative activity, buckwheat,correlation analysis lNTRODUCTlO(来源：淘豆网[/p-7115411.html])N The genus Fagopyrum includes ten—odd species (Morishita et a1.2007).Among them,Fagopyrum esculentum MOench(FEM,three varieties)and Fagopyrum tartaricum L.Gaerth(FTG,seven varieties) have been m ainly cultivated for their value as food ingredients.Buckwheat grain has a higher antioxidative activity and phenolic content than other cereal grains (Zieliski et a1.2000;Inglett et a1.20 1 1;S9dej et a1. 2012).EpidemiologJ cal studies revealed that buckwh(来源：淘豆网[/p-7115411.html])eat can reduce the risk of chronic diseases,and the benefi— cia1 effects of buckwheat have attributed to its high levels of antioxidants,such as tocopherols and polyphe— nols etc.(Holasovaa et a1.2002;Sun and Ho 2005: Guo eta1.2011 . Polyphenols have an ideal antioxidant structure,due Received 29 Ocotober,2012
Accepted 8 January,2013 LI Fu—hua,E—mail:fuhualee92@ ;c0rresp0ndence MING Jian,Tel:+86—23—,Fax:+86-23—,E-mail:mingjian1972@1(来源：淘豆网[/p-7115411.html])63.tom @2013,CAPS Allnghts reser,,,ed PuNishedbyElsevierLtd doi:10 1016/￥ Phenolic Profiles and Antioxidant Activity of Buckwheat(Fagopyrum esculentum M6ench and Fagopyrum tartaricum
1 6 8 5 to the presence of an arom atic phenolic ring that can stabilize the unpaired electron(Kong and Lee 20 1 0).Polyphenols especially phenolics of fruits, cereals and vegetables are the maj or pounds for health benefits,including antibacterial,(来源：淘豆网[/p-7115411.html])antiviral,anti—inflam matory,antiallergic, antithrombotic,and vasodilatoryactions(Vahereta1.2010;Babbareta1.2011: Inglett etaL 2011;Rockenbach et a1.2011;Sharma et a1.2012).Therefore, the potential of plant phenolics for the maintenance of health and protec. tion from coronary
heart disease and cancer is raising interest am ong researchers. The polyphenols of cereals occur in both free and bound forms.Usually. free phenolics are found in outer laye(来源：淘豆网[/p-7115411.html])r of the pericarp,and bound phenolic are esterified to eell walls(Dykes et a1.2007;Pereezqimenez et a1.201 l、. Hung and Morita(2008)found that buckwheat contains a majority of pounds present in the free form .In contrast.— pounds of other cereal grains are primarily bound to cell ponents (Adom and Liu 2002). The polyphenolic content and antioxidant capacity of buckwheat flour
have been previously investigated,especially,buckwheat flour Of FEM
(Pen(来源：淘豆网[/p-7115411.html])g et a1.2004;Hung et a1.2008;Sedej et a1.2010;Verardo et a1. 2O l 0:Inglett et a1.20 1l 1.However,there is few research on the distri— bution and quantification of polyphenols and antioxidant activity in hulls brans,and flours betw een different FEM
and FTG buckwheat cultivars growing in different locations.The objective of this study was to:(1) investigate the distribution and quantification of free and boun d pounds,as well as their antioxidant activity in hulls,brans and flours of FEM (three varieties)and FTG(seven varieties);(2)elucidate the possible correlations between total phenolic content,reducing power and DPPH free radical scavenging activity of hulls.brans and flours of FEM (three varieties)and FTG(seven varieties). RESULTS The distribution and quantification of free and bound phenolics in hulls, brans and flours of ten buckwheat cultivars w ere presented in Table 1, expressed as mg GAE g。DW (mg gallic acid equivalent per g dry—weight basis). The free and bound phenolics content of ten buckwheat hulls brans and flours The free phenolic content of ten buckwheat hulls ranged from 9.34 m g GAE g DW (S4)to 2 1.32 mg GAE g。DW (S2).The bound phenolic content ranged from 1.24 mg GAE g0 DW (S2)to 5.03 mg GAE g0 DW
(S5 .The total phenolic content(TPC)ranged from l3.59 mg GAE g0 DW (S4)to 26.19 mg GAE g DW (S1).Free phenolics were predomi— nant in buckwheat hulls。accounting for about 79。7O% of the TPC on a @2013 CAAS Allfightsreserved Published byElsevierLtd 口唇n1。U ^1芑uds。 暑口【s
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LI Fu—hua et al per weight basis.parisons of free,bound and TPC among FEM (S 1.s3)hulls and FTG(S4一S 1 0)hulls, the average values of free,bound and TPC of FEM
hulls were 20.23.3.61,and 23.83 m g GAE g~ DW , respectively,and the relevant average values of FTG hulls were 13.89.3.91 and 18.09 mg GAE g— DW
respectively.It is evident that FEM
hulls have higher TPC and free phenolics content than that Of FTG hulls. The free phenolic content of ten buckwheat brans ranged from 7.65 mg GAE g。DW (S3)to 25.56 mg GAE g。DW (S7).The bound phenolic content ranged from 0.19 mg GAE g。DW (S2)to 2.36 mg GAE g。 DW (S5).TheTPC rangedfrom 8.76mgGAEg。DW (S3)to 27.1 8 mg GAE g。DW (S7).Free phenolics were predom inant in buckwheat brans,accounting for about 92.89% Of the TPC on a per weight basis. parisons of free,bound and TPC among FEM (S 1. S3)brans and FTG(S4_S 1 0)brans the average values of free.bound and TPC of FEM brans were 11.63. 1.03 and 12.66 mg GAE g。DW ,respectively,and the relevant average values Of FTG brans w ere 23.1 6. 1.71 and 24.9 m g GAE g~DW .respectively. It is evident that the brans of FTG have higher TPC and free phenolics content than that of FEM
brans. The free phenolic content of ten buckwheat nours ranged from 8.05 mg GAE g DW (S2)to 15.11 mg GAE g。DW (S5).The bound phenolic content ranged from 0.57mgGAEg DW (S2)to 0.99mgGAEg DW (SlO).The TPC ranged from 8.62 mg GAE g DW (S2) to 1 5.85 mg GAE g。DW (S5).Free phenolics were predom inant in buckwheat flour,accounted fo r about 94.07% Of the TPC on a per weight basis. Hung and Morita(2008)reposed that free phenolic content ofbuck- wheat flour(FEM 、was significantly higher than that of the bound phenolic content.parisons offree,bound and TPC among FEM (S1一S3)flours and FTG(S4.S10) flours,theaveragevalues offree,boun dandTPC ofFEM
flour w ere 9.03.0.68 and 9.70 m g GAE g~ DW . respectively,an dthe relevantaveragevaluesofFTG brans were 13.08,0.78 and 13.86 mg GAE g DW ,respectively. It is evident that the flour s ofFTG have higher TPC and free phenolics content than that ofFEM
flour s. DPPH free radical scavenging activity DPPH free radical scavenging activity was widely used to evaluate antioxidant activity of pounds extracted from fruit and vegetable,cereal grain,etc. (Ferreira et a1.2007;Babbar et a1.2011:Eva et a1. 2012).The IC was defined as the extract concentra— tion that caused a decrease in the initial DPPH free radi- cal concentration by 50% ,and the lower IC 0,the higher the antioxidant activity of
pound is.This assay parison of the reactivity of powerful oxi— dants such as ascorbic acid with phenolic extracts ob— tained from hulls(Fig.1),brans(Fig.2),and flours (Fig.3、of ten buckwheats. In Fig.1,the free IC 0( g mL )ranged from 35.0 30.0 25 0 20 0 15.0 1O 0 5.0 O.O 皿 The IC5()ofVC ● The IC5o of free phenolics ofhulls 2
l0 Varieties Fig.1 The IC5o( g mL。)of free and bound phenolic extracts of ten buckwheat hulls and ascorbic acid in DPPH free radical scavenging assay.Values are means oftriplicate measurements￣SD. The same as below . 50 0 45 0 40.0 35 O 30.0 25 0 20 0 l5 0 l0.0 5.0 0.0 皿 The 1C50 ofVC ■ The/C_s0 of free phenolics of&brans 2
lO Varieties Fig.2 The IC50(gg mL。)of of free and bound phenolic extracts of ten buckwheat brans and ascorbic acid in DPPH free radical scavenging assay. @ 2013 CAAS All nghts reserved PublishedbyElsevierLtd Phenolic Profiles and Antioxidant Activity of Buckwheat(Fagopyrum esculentum M6ench and Fagopyrum tartaricum
1 687 3.45 gg mL。(S1)to 12.09 gg mL。(S10).The bound IC n(1ag mL。)ranged from 4.56 lag mL。(s1)to 22.13 gg mL。(S7),the free IC n were lower than that of the bound for the major hulls.The total ICsn(1ag mL。) ranged from 8.00 lag mL~(so to 29.70 g mL (S7), i.e.,most of the free phenolics in hulls had higher anti— oxidant activity than that of the bounds.and S 1 had the highest antioxidant activity in hulls tested here and ascorbic acid 0c
8.39 gg mL。),S7 had the lowest antioxidant activity among the ten buckwheat hulls tested. In Fig.2,the free ICs0( g mL。)ranged from 2.80 gg mL。(S8)to 6.44 gg mL (S1).The bound ICs0 (1ag mL。)ranged from 21.89 g mL (S8)to 36.86 lag mL。(S9),the free IC50 were lower than that ofthe bound for the major brans.The total IC50(1ag mL。) ranged from 24.69 lag mL。(S8)to 40.29 lag mL。(S9),i.e.,most ofthe free phenolics in brans had higher reducing pow er than that of the bounds.and S8 had the highest antioxidant activity in brans studied here, but lower than ascorbic acid(IC
8.39 lag mL。),S9 had the lowest antioxidant activity among the ten buck— wheat brans tested. In Fig.3,the free IC n(Pg mL。)ranged from 3.45 lag mL。(S6)to 8.82 lag mL (S3).The bound IC50 (1ag mL )ranged from 19.50 lag mL (S6)to 40.79 lag mL。(s8),the free IC50 were lower than that ofthe bound for the major flours.The total IC 0(/xg mL ) ranged from 22.95 lag mL。(S6)to 46.59 lag mL。(S2),i.e.,most of the free phenolics in flours had higher antioxidant activity than that of the bounds,and S6 had 60.0 50 0 — 40.0 望 30 0 20 0 i0·0 0.0 皿 TheIC ofVC ■ The IC50 of flee phenolics of flours 2
l0 Varieties the highest antioxidant activity in flours examined here, but lower than ascorbic acid(IC5o,8.39 g mL。),S2 had the lowest antioxidant activity among the ten buck— wheat flours tested. Reducing power In reducing power assay,the EC如was calculated from the graph of absorbance at 700 nln against extract con— centration and defined as the extract concentration pro— viding 0.5 of absorbance,and the lower ECs0,the higher the antioxidant activity of pound is(Ferreira et a1. 2007;Hung et a1.2008).This assay pari— son of the reactivities of powerful oxidants such as ascorbic acid with phenolic extracts obtained from hulls (Fig.4),brans(Fig.5),and flours(Fig.6)of ten buckwheats. In Fig.4,the free ECsn( g mL )ranged from 8.29 lag mL (S3)to 97.78 lag mL。(S2).The bound EC50 (1ag mL。)ranged from 4.25 lag mL。(S4)to 204.88 lag mL (S7),the free EC50 were lower than that of the bound for the major hulls.The total EC 0( g mL。) ranged from 42.2 g mL (S1)to 219.87 lag mL。(S7), i.e.,most ofthe flee phenolics in hulls had higher reduc— ing power than th at ofthe bounds,and S1 hadth e high— estreducingpowerinhulls studiedhereaswellas ascorbic acid(EC
57.63 g mL ),S7 had the lowest reducing power among the ten buckwheat hulls tested. In Fig.5,the free EC50(1ag mL。)ranged from 4.72 25O 200 毫 5 兰 100 5O 0 皿 The EC5fl ofVC ■ The ECs0 offlee phenolics ofhulls 口 The ECso ofbotmd phenolics ofhulls l
l0 Varieties Fig.3 The IC ( g mL一)of free and bound phenolic extracts of ten buckwheat flours and ascorbic acid in DPPH free radical
Fig.4 The EC50(gg mL。)of free and bound phenolic extracts of scavenging assay. ten buckwheat hulls an d ascorbic acid in reducing power assay- @2013,CAAS.All哟hts reserved PublishedbyElsevierLtd l688
LI Fu.hua et al 一 ￡∞ U
山 皿 The ECs0 ofVC — TheEC50offleephenolics ofbrans 口 The ECs0 ofbound phenolics ofbrans j
J0 Varieties Fig.5 The EC50(gg mL )offfee and bound phenolic extracts of ten buckwheat brans and ascorbic acid in reducing power assay. 350 0 300.0 250.0 l— g
200 0 暑 l50.0 U
山 100.0 50.0 0.0 皿 TheEC50 ofVC — The EC50 offlee phenolics offlours 口 The EC 0 of bound phenolics of flours 2
】0 Varieties Fig.6 The EC50(Pg mL )of free and bound phenolic extracts of ten buckwheat flours and ascorbic acid in reducing power assay. g mL
(S8)to 100.07 lag mL (S3).The bound EC50(1ag mL。)ranged from 13.97 lag mL。(S2)to 1 I8.69 lag mL。(S9),the free EC n were lower than that of the bound for the major brans.The total EC ranged from 31.12
g mL。(S2)to 159.82 lag mL (S3),i.e.,most ofme free phenolics in brans had higher reducing power than that of the bounds.and S2 had the highest reducing pow er in brans studied here as well as ascorbic acid(EC
57.63 lag mL。),s3 had the lowest reducing power am ong the ten buckwheat brans tested. In Fig.6,the free EC5o(1ag mL。)ranged from 29.99 gg mL (S4)to 68.91 lag mL。(S2).The bound EC5o (gg mL。)ranged from 32.06 g mL。(S5)to 283.75 lag mL。(S4),the free EC5n were lower than that ofthe bound for the major flours.The total EC50(1ag mL。) ranged from 82.78 lag mL‘(s51 to 313.75 lag mL (S4),i.e.most of the free phenolics in flours had higher reducing power than that of the bounds.and S5 had the highest reducing power,but lower than ascorbic acid(EC
57.63 lag mL ),S4 had the lowest reduc- ing power among the ten Buckwheat flours tested. Relationship between TPC,DPPH free radica scavenging abilities and reducing power The correlation between TPC and antioxidant activity has been widely studied jn different foodstuffs.such as fruits and vegetables(Kaur and Kapoor 2000;Hodzic ef a1.2009:Babbar et a1.20 ll 1.Previous studies dem onstrated a linear correlation between phenolic content and antioxidant ability in fruits and vegetables. W hereas,this was not true for all the stuffs analyzed fo r phenolic content and antioxidant activity fDeleu ef a1.2000;Kaur and Kapoor 2000;H olasovaa et a1. 2002;M orishita et a1.2007;Babbar et口,_20l11. In this paper,the possible correlations betw een TPC,re— ducing power and antioxidant activity of hulls,brans and flours of ten buckwheats were explored(Table 21. The hull extract of S4 with lowest TPC am ong all hulls analyzed here。exhibited higher DPPH free radical scavenging ability than hull extracts ofS3,S5一S10,as well as higher reducing power parison with hull extracts of S2,S3,S5,S7一S10.The relavent r were shown in Table 2.Especially,the
.re. ducing power was 0.75&ro_o 5f】0 0.648,i.e.,DPPH free radical scavenging ability and reducing power showed a high correlation for the buckwheat hull extracts ex. am ined here. The correlation among TPC.DPPH free radical scav. enging ability and reducing power of bran extracts showed a weak correlation(Table 2、.Bran extracts of S7.with highest TPC am ong all bran samples tested here,whereas,exhibited weaker reducing power than bran extracts of Sl,S2,S6,S8,and S10,as well as weaker DPPH free radical scavenging ability . parison with bran extracts of S1一S6 and S8.the relvent was shown in Table 2. The correlation between TPC and reducing power ￣ 2013,CAAS AU righis reserved Published by Elsevier Ltd 舳∞∞加∞蛐∞加如 0 Phenolic Profiles and Antioxidant Activity of Buckwheat(Fagopyrum esculentum M6ench and Fagopyrum tartaricum
1 689 Table 2 Correlation between TPC,reducing power and DPPH free radical scavenging ability,reducing power and DPPH free radical scavenging ability of ten buckwheat hulls,brans and flours ) ”The correlation between total phenolic content,reducing power and DPPH free radical scavenging ability of hulls,brans and flours of ten buckwheats varieties w as evaluated with Spearman rank correlation analysis,expressed as rank correlation coefficient( ). 0 o5f101 0.648 for the flour extracts of ten buckwheats was high (
0.79&r 0.05(10)￣0.648),the similar result was in agree— ment with previously reported literature.Holasovaa et a1. (2002)indicated that statistically significant relation— ships were observed betw een TPC and antioxidant ac— tivity
=0.987,P&O.002).In contrast,Inglett et a1. (20 1 1)reported that there were no significant differ- ences among four buckwheat flours(FEM)between the antioxidant activity and free,bound phenolic contents. DISCUSSlON This study showed that the average TPC of ten buck- wheat hulls.brans and flours were 19.61,21.12 and 12.61 mg GAE g—DW .respectively.Free phenolics content ofbuckwheat hulls,brans and flours,accounted for about 79.70,92.89,94.07% ,respectively,i.e.,free phenolics were the predominant form in buckwheat hulls, brans and flours.By contrast,the phenolics in wheat, rye,corn,oat,and rice exist primarily in the bound form (Adom and Liu 2002;Vaher et口f_2010:Pereez— jimenez and Torres 20l1).Besides,The TPC ofbuck— wheat hulls and brans analysed here were higher than that of flours.This result was in agreement with previ— ously reported literatures.Peng et a1.(2004)found that the content of(一)一epicatechin,rutin,hyperoside and quercetin,except(一)一epicatechin,in hulls were higher than in flours.Hung et a1.(2008)reported the outer layers of buckwheat grains with larger phenolics content than the inner fraction.Inglett et a1.(20 1l 1 indicated that the hull and aleurone layer are richer in m any
pounds than whole buckwheat flours. In term s of variety difference,the average values of TPC of FEM
hulls,brans,flours w ere 23.83,12.66 and 9.7 mg GAE g。DW ,respectively,the relavent av— erage values ofFTG were 18.09.24.87 and l3.86 mg GAE g‘ DW . Except hulls,TPC of FTG brans and flours w ere higher than FEM
brans and flours, especially,FTG brans had the highest TPC am ong all samples examined here.Free phenolics were predomi— nant in the two varieties which were also reported by Guo et a1.(201 11 and Hung et a1.(2008). In DPPH free radical scavenging assay,the IC n was defined as the sample concentration that caused a de— crease in 抽e initial DPPH concentration by 50%.and the lower IC 0,the higher the antioxidant activity of pound is. In this paring with flours (37-30 g mE-1),the average total IC50 of hulls(1 8.46 gg mL。)and brans(34.1 2 g mL。)were relatively 1ow.i…e the antioxidant activity ofhulls and brans were higher than flours.This results were made agree with the result of other cereals Eva et a1.(20 1 2)reported that flour fractions showed lower proportion of the to— tal antioxidant potential than bran fractions(fine bran and coarse bran)in wheat,triticale,rye and barley.In term s of variety difference,the average total IC50 Of FEM
hulls,brans,flours were 11.58,33.60 and 39.35 g m L~,respectively,the relevant average values of FTG were 21.41,34.35 and 36.41
g mL。。,respectively. The FEM
hulls had the highest antioxidant activity. W hereas,the FEM
flours had the lowest antioxidant activity.and Morishita et a1.(2007)reported that in DPPH free radical scavenging assay,the antioxidative activity of FTG flour was 3-4 times higher than that of FEM . In reducing power assay,the EC n was calculated from
the graph of absorbance at 700 nm against ex— tract concentration and defined as the extract concen— tration providing 0.5 of absorbance,the lower EC50, the higher the antioxidant activity of pound is.In this pared with flours(141.18 g mL。),the average total IC5n of hulls(1 1 2.34 gg mL。)and brans (98.98 g mE-1)were relatively lower,i.e.,the antioxi一@2013 CAAS All rights reserved PublishedbyElsevierLtd l690
LI Fu—hua et al dant activity of hulls and brans were higher than flours. In terms of variety difference,the average total EC5n Of FEM
hulls。brans,flours were 84.22,86.54 and l 3 1.54 g m L~,respectively,the relevant average values of FTG were 124.39,104.3 1 and 145.30 LLg mL~, respectively. It was evident that hulls and brans of FEM ,as well as FTG,had higher reducing power than the relevant flours,especially,hulls of FEM
had the highest reducing power. A11 the extracts obtained from the hulls.brans and flours of ten buckwheats showed antioxidant capacity, although with different e筒 ciencies. The correlation between TPC and antioxidant activities of hulls and brans were not statistically significant with the excep— tion of flours(Table 2、.The correlation between the DPPH free radical scavenging ability vs.reducing power of brans and flour s was not statistically significant with the exception ofhulls(Table 21.The bran of S7(27.17 mg GAE g~DW)had the highest phenolic content。 whereas,the hull of S8(IC
8.0 g mL。)showed the highest DPPH free radical scavenging ability.and the bran of S8(EC
31.12 g mL。)showed the highest reducing power
功 ns.the relationship between the an— tioxidant activity and TPC of buckwheat extracts
plex and diffi cult to describe by statistical tools. There are several reasons to explain the ambiguous rela— tionship betw een TPC,reducing power and DPPH free radical scavenging ability:(1)TPC ofbuckwheat did not include all the antioxidants(e…g ascorbic acid,carotenoid, vitamin E,p—glucan,etc.),and the synergism among the phenolics or non—phenolics affects the antioxidant activity,as a result,antioxidant activity not only depen— dent on the concentration of antioxidants,but also on the profile ofthe antioxidants(Sun and Ho 2005;Babbar ef a,.20l1、.Morishita et a1.(2007)reported that the sum of the contribution rate of all confirmed antioxi— dants((一)-epicatechin+(一)一epicatechingallate+rutin)was only about one—fifth of the total antioxidative activity. (2)Cultivars,environmental factors,growing season, fractions influenced the antioxidant activity ofbuckwheat f0omah and M azza 1 996;Sun and Ho 2005:Guo Pf日,.20ll、.Morishita et a1.(2007)reported that,in FEM,(一)一epicatechin was the maj or contributor of antioxidative activity,whereas,rutin was the maj or contributor in FTG.r3 1 Different methods to mea— sure antioxidant activity with various m echanisms m ay lead to different observations(Sun et a1.2005). M aking prehensive analysis on this paper,the hulls and brans often buckwheats,particularly,the hulls and brans of FTG showed higher antioxidant capacity than relevant flours. Thus,hulls and brans of buckwheats,due to the low cost and easy availability, can serve as good substrates offering significantly low— cost.nutritional dietary supplements and pounds.and had a trem endous potential in food and pharm aceuticalindustry.Otherwise.more studies are needed to determ ine the antioxidant ability of non— pounds present in buckwheat hulls,brans and flours,as well as,to establish bioavailability and real benefits of these extracts obtained from hulls and brans of buckwheats studied here in vivo. CONCLUSlON The results of this study showed that free phenolics were the predominant form
in buckwheat hulls,brans and flour s,and the TPC of buckwheat hulls and brans analysed here were higher than that of flours.In term s of variety difference.except fo r hulls.TPC Of FTG brans and flours were higher than that of FEM . especially.FTG brans had the highest TPC am ong all samples examined here. The extracts obtained from the hulls,brans and flours of ten buckwheats showed antioxidant capacity.although with difrerent effi ciencies. The correlation betw een TPC and antioxidant activities of hulls and brans were not statistically significant with the exception of flours. MATERIALS AND METHODS A11 the buckwheat samples used in this study were har. vested in 201 1.except for S10 which was harvested in 2012 (Table 3、.The ten buckwheat samples can be divided into two subspecies:FEM (three varieties)and FTG (seven varieties).A11 buckwheat varieties were roughly crushed in a blender,and separated into the hull,the bran and the flour on different sieves,the hull on the 40.m esh sieves, the flour under the 60.mesh sieves and the bran between 40.60 mesh sieves.A11 samples were stored at.20。C until analysis within 1 mort. Extraction of free and bound phenolics Free and bound phenolics of buckwheat fractions were @ 2013.CAAS All rights reserved PublishedbyElsevierLtd Phenolic Profiles and Antioxidant Activity of Buckwheat(Fagopyrum esculentum MSench and Fagopyrum tartaricum
1 69 1 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 Fagopyrum esculentum M Oench Fagopyrum esculentum M 6ench Fagopyrum esculentum M 6ench Fagopyrum tartaricum L.Gaerth Fagopyrum tartaricum L.Gaerth Fagopyrum tartaricum L.Gaerth Fagopyrum tartaricum L.Gaerth Fagopyrum tartarieum L.Gaerth Fagopyrum tartaricum L.Gaerth Fagopyrum tartaricum L.Gaerth Huanxian County.Gansu Province Suzhou County,Shanxi Province Qingyang County,Gansu Province Huanxian County.Gansu Province Taiyuan County,Shanxi Province Qingyang County,Gansu Province Liangshan prefecture,Sichuan Province Liangshan prefecture,Sichuan Province X iehang City,Sichuan Province Youyang County,Chongqing M unicipality S7 and S8 growing in the sam e location belong to tw o cultivars ofFagopyrum tartaricum L.Gaerth. and S8 was named Fagopyrum tartaricum L.Gaerth III extracted using a slight m odification of the method previ. ously reported by Adom and Liu(2002)and Hung et a1. (2008).Briefly,buckwheat hull,bran,flour(1 g)were blended with 50 mL of 80% chilled acetone for 1 0 min using high—speed hom ogenizer,respectively. A fter centrifuga— tion at 3 500xg for l 0 min。the supernatant was collected. The residue was re.extracted twice under the same conditions. A 11 supernatants w bined and evapo— rated at 45。C to dryness under reduced pressure.Then the concentrated slurry was dissolved with 25 mL methanol and got free phenolic extract.then stored at.80。C until analysis w ithin three days. The residue from
the free phe— nolic extraction was digested with 20 mL of 2 mol L~so. dium hydroxide at room temperature for 90 min with shak— ing in dark place.The hydrolysate was acidified to pH 2 and was extracted twice with hexane to remove free fatty acids and other lipid contaminants.The liberated phenolic acids were then extracted five times with ethy1 acetate. The ethyl acetate fractions were pooled and evaporated at 45。C to dryness under reduced pressure.and then bound pounds were dissolved with 1 0 mL methanol and got bound phenolic extract,then stored at一80。C until analysis within 3 d. Determination of phenolic content Phenolic content of buckwheat extracts were determined by the Folin.Ciocalteau colourimetric method as described by Adorn and Liu(2002)and Hung et a1.(2008).Briefly, 0.1 mL offree phenolics ofbuckwheat extracts(or 0.2 mL of bound phenolics of buckwheat extracts)were made to 1.0 mL with methanol,then,Folin.Ciocalteau reagent f0.2 mE) was added to the solution.2 mL of 7% Na,CO and 1.6 mL of deionised water were added after 6 min.Then mixed on a vortex mixer and the resulting solution were incubated in the dark for 90 min at room temperature.Absorbance was measured at 760 nm. Gallic acid was used as a standard and a calibration curve was prepared with a range of con. centrations from 0 to 60 ug mL。。.The results are expressed as mg GAE g~DW .The assays were carried out in tripli— cate and the results are expressed as mean values土standard deviations. Determ ination of DPPH free radical scavenging capacity The free radical scavenging capacity of the sample extracts was examined using a modification of the method previ. ously described by Alvarez—Jubete et aL(20 1 O1 and Vaher M
a1.(20 1 0).Buckwheat extracts fthe concentration of free and bound phenolic methanolic extracts ranged from 0.25 to 5 g mL~,0.55 to 1 1 g mL~,respectively)in metha- no1 f1 mE)were mixed with 5 mL of a freshly made DPPH methanolic solution f0.1 mmo1 L-11.The absorbance of the freshly prepared DPPH solution was measured prior to analysis.After being shocked,the mixture was incubated in the dark fo r 30 min at room temperature.The absor— bances were then measured at 5 1 7 am using a spectropho— tometer(UV-722,Jinghua,Shanghai,China).The DPPH free radical scavenging activity of the sample was calcu. 1ated as fo llows: DPPH free radical scavenging activity(%)=(1一Absor- bance of sample/Absorbance of contro1)x 1 0O As the DPPH was reduced by the amount of antioxi dants present in the sample,the colour of the solution faded in a proportional correlation to the antioxidant cOncentration. Ascorbic acid was used as standard and the concentration of the ascorbic acid ranged from 1 to 1 2 gm L~. Determination of reducing power The reducing power of methanolic extracts was determined according to the method of Ferreira et a1.(2007)and Babbar 口(20 ll、.Each sample of buckwheat extracts at differ— ent concentrations.Briefly,0.2,0.3,0.4。0.6,and 0.8 mL of bound phenolic methanolic extracts(the amount of free phenolic methanolic extracts by haln were made to 1 mL with methanol respectively.Then mixed with 2.5 mL of phosphate buffer(0.2 mol L一,pH 6.6)and 2.5 mL ofa potas— sium ferricyanide solution r 1%,w/v).The mixture was in. cubated at 50。C for 20 min.Then.2.5 mL of a TCA solution r 1 0%,w/v)was added,and the mixture was then centri. fuged at 3 000￣g for 10 min A 2.5 mL aliquot ofthe upper ￣ 2013,CAAS All rights reserved PublishedbyElsevierLtd l692
LI Fu—hua et al 1ayer bined with 2.5 mL of distilled water and 0.5 mL of a ferric chloride solution(0.1%,w/v),and the absor— bance was measured at 700 am.The assays were carried out in triplicate and the results are expressed as mean va1ues土standard deviations. Ascorbic acid was used as standard and the concentration of the ascorbic acid ranged from
10to 1O0 UgmL。。. Statistical analysis A1l experiments were done in triplicate and the results were reported as mean士standard deviation fSD1. Standard deviation,ICsn and EC n were calculated using M S Excel software.The difference between means was determined by Duncan’s m ultiple range tests by using the SPSS16.0 statistics softw are. Results were considered statistically significant at P&0.05.The correlation between total phe— nolic content,reducing power and antioxidant activity of hulls.brans and f1ours of ten buckw heats varieties w as evaluated with Spearman rank correlation analysis,ex— pressed as rank correlation coeffi cient
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