不同方式提取的近江牡蛎糖蛋白的体外抗氧化活性

比较研究了水浸提、盐液浸提及超声辅助盐液浸提的近江牡蛎糖蛋白粗提物对羟自由基、DPPH自由基、超氧阴离子自由基的清除效果。结果表明:水浸提、盐液浸提及超声辅助盐液浸提的糖蛋白中可溶性蛋白与总糖含量之比分别为1.83∶1、4.49∶1和2.51∶1;3种糖蛋白粗提物均具有一定的清除羟自由基、DPPH自由基和超氧阴离子自由基的能力;它们对羟自由基的清除能力高于对DPPH自由基和超氧阴离子自由基;盐液浸提物清除超氧阴离子的能力最弱;超声辅助盐液浸提的糖蛋白粗提物清除羟自由基、超氧阴离子自由基及DPPH自由基的能力比水浸提和盐液浸提的糖蛋白的能力强。     

芒果粉对真空油炸面包虾裹浆特性及其品质的影响

【目的】研究添加芒果粉对真空油炸面包虾裹浆特性及其品质的影响。【方法】以小麦粉和大豆分离蛋白的裹浆作为对照,研究芒果粉替代部分小麦粉和大豆分离蛋白的裹浆流变学特性;以裹涂率、油脂含量、水分含量、色泽及质构特性为考察指标,研究芒果粉替代部分小麦粉和大豆分离蛋白的裹浆对真空油炸面包虾品质的影响;以最佳芒果粉添加量的真空油炸面包虾为研究对象,测定外裹层黄酮物质含量,并采用羟自由基和DPPH自由基体系对产品外裹层黄酮物质的抗氧化性进行分析。【结果】所有配方的裹浆均表现为触变性,呈现剪切稀化特性,具有假塑性流体特征,并符合幂率流体,芒果粉可显著提升裹浆的黏度;芒果粉可显著增大面包虾裹涂率,改善产品质构和色泽特性,降低产品油脂含量并提升其水分含量(P <0.05)。当芒果粉添加量从10%增加到30%时,面包虾产品油脂质量分数从24.84%降低到20.58%,产品的脆性和色泽中的亮度值(L*)、黄度值(b*)均得到了显著提升(P <0.05)。当小麦粉质量分数66%、大豆分离蛋白质量分数4%、芒果粉质量分数30%时,真空油炸面包虾产品的各项品质最佳;真空油炸面包虾产品外裹层黄酮物质质量分数为(46.75±2.87)mg/100g,其对羟自由基和DPPH自由基的清除效果方面都均强于维生素C。【结论】芒果粉可提升裹浆黏度,改善真空油炸面包虾产品品质,其外裹层较强的抗氧化性对于真空油炸裹涂制品延长货架期具有一定积极作用。     

The antioxidant effects of complexes of tilapia fish skin collagen and different marine oligosaccharides

An excess of reactive oxygen species (ROS) leads to a variety of chronic health problems.As potent antioxidants, marine bioactive extracts containing oligosaccharides and peptides have been extensively studied.Recently, there is a growing interest in protein-polysaccharide complexes because of their potential uses in pharmaceutical and food industries.However, only few studies are available on the antioxidant activities of such complexes, in terms of their ROS scavenging capability.In this study, we combined different marine oligosaccharides (isolated and purified) with collagen peptides derived from tilapia fish skin, and evaluated the an-tioxidant activity of the marine peptide-oligosaccharide complexes vis-à-vis the activity of their original component molecules.Bio-chemical and cellular assays were performed to measure the scavenging effects on 1, 1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide radicals, and to evaluate the influences on the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the level of malondialdehyde (MDA) in UV-induced photoaging models.The results indicated that the antioxidant activities of all the complexes were stronger than those of their individual components.Among the 11 complexes tested, two complexes, namely MA1000+CP and κ-ca3000+CP, turned out to be highly effective antioxidants.Although the detailed mechanisms of this improved scavenging ability are not fully understood, this work provides insights into the design of highly efficient peptide-oligosaccharide complexes for potential applications in pharmaceutical, cosmetics and food industries.     

Study on the Free Radical Scavenging Activity of Sea Cucumber （Paracaudina chinens vat.） Gelatin Hydrolysate

Gelatin from the sea cucumber （Paracaudina chinens var.） was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff （MWCO）. The portion （less than 5 kDa） was further separated by Sephadex G-25. The active peak was collected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals （O2·^-） and hydroxyl radicals （·OH） of the fraction with the highest activity were 29.02% and 75.41%, respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria.     

The preparation and antioxidant activity of glucosamine sulfate

Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O-2)/hydroxyl (·OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfa...     

Study on the Free Radical Scavenging Activity of Sea Cucumber(Paracaudina chinens var.) Gelatin Hydrolysate

Gelatin from the sea cucumber(Paracaudina chinens var.) was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff(MWCO). The portion(less than 5 kDa) was further separated by Sephadex G-25. The active peak was col-lected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals(O2·-) and hydroxyl radi-cals(·OH) of the fraction with the highest activity were 29.02% and 75.41%,respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria.     

Free radical scavenging abilities of polypeptide from Chlamys farreri

1 INTRODUCTION Active oxygen free radicals can damage cell structure, even kill the cells, causing aging and cer- tain serious diseases (Bors et al., 1989). Usually, the production and scavenging of active oxygen free radicals are in balance in healthy hu…     

Studies on free radical scavenging activity in Chinese seaweeds part I. Screening results

INTRODUCTIONIthaslongbeenknownthatfatsundergoslowautoxidationduringstorage;andthatantioxidantswhichscavengefreeradicalsexistingduringtheinitialstageorearlypropagationstageoflipidoxida tioncanpreventrancidity ,soantioxidantsareoftenusedasfoodadditivescapableofdelaying ,re tardingorpreventingtherancidityinlipidsduetooxidation .Inthissense ,anidealantioxidantshouldhavethefollowingcharacteristics:safeinuse ,noodor,flavororcolor,effectiveatlowcon centration ,easytoincorporateandavailableatlowco…     

The scavenging of free radical and oxygen species activities and hydration capacity of collagen hydrolysates from walleye pollock (Theragra chalcogramma) skin

Fish skin collagen hydrolysates (FSCH) were prepared from walleye pollock (Theragra chalcogramma) using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of <1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical (DPPH), superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione (GSH). FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore, FSCH may have potential applications in the medicine and food industries.     

The Scavenging of Free Radical and Oxygen Species Activities and Hydration Capacity of Collagen Hydrolysates from Walleye Pollock(Theragra chalcogramma) Skin

Fish skin collagen hydrolysates (FSCH) were prepared from walleye pollock (Theragra chalcogramma) using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of <1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical (DPPH), superox-ide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione (GSH). FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scav-enge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore, FSCH may have potential applications in the medicine and food industries.     

The Effect of Hydrolysis with Neutrase on Molecular Weight,Functional Properties,and Antioxidant Activities of Alaska Pollock Protein Isolate

In this study, the Alaska pollock protein isolate(APPI) was hydrolyzed by Neutrase for 20, 40, 80, 120, 160, 200, and 240 min. Hydrolysates with different molecular weights were produced and they were named as H1–H7. Furthermore, the effects of hydrolysis on the average molecular weights, functional properties(solubility, oil-holding capacities, foaming activities, and emulsifying properties), and antioxidant activities(1, 1-diphenyl-2-picrylhydrazyl, superoxide, and hydroxyl free radical-scavenging activities) were determined. It was found that when the degree of hydrolysis(DH) increased, the average molecular weights of the hydrolysates decreased significantly. The functional properties of APPI were also significantly improved. The hydrolysates of APPI exhibited better solubility, emulsifying activities, and foaming activities. Hydrolysates with low molecular weights(1 kDa) had better solubility, oil-holding capacities, and emulsifying activities, while hydrolysates with higher molecular weights(1 kDa) had better foaming activities. In addition, the hydrolysates exhibited excellent antioxidant properties, while the inhibition values of 1, 1-diphenyl-2-picryl hydroxyl(DPPH), superoxide, and hydroxyl free radical-scavenging activities, were 85.22%, 53.56%, and 75.00% respectively, when the concentration of the hydrolysates was 5.0 mg mL~(-1). The lower the average molecular weight was, the higher was the antioxidant activity. These results indicated that hydrolysis with Neutrase is an effective method for improving the functional and antioxidant properties of APPI. The hydrolysates of APPI displayed great potentials to be used as natural antioxidants in protein-rich aqueous foods such as nutrient supplements and sports beverages.     

扁舵鲣抗氧化肽分离纯化及结构鉴定

【目的】从扁舵鲣(Auxis thazard)的木瓜蛋白酶酶解产物中分离鉴定具有较高1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率的抗氧化肽。【方法】用木瓜蛋白酶水解扁舵鲣,以DPPH自由基清除能力为检测指标,通过超滤、凝胶过滤层析和反向高效液相色谱分离抗氧化肽,再经过超高效液相/三重四级杆飞行时间质谱(UPLC/Xevo G2-XS QTOF)进行结构鉴定。【结果】从酶解产物中获得3种抗氧化肽,其氨基酸序列分别为β-丙氨酸-1-甲基-L-组氨酸(241 u)、Gly-Ala-Gly-Gly-Pro(357 u)和Val-Glu(246 u)。【结论】扁舵鲣的木瓜蛋白酶酶解产物含有抗氧化活性的肽类,可为其抗氧化肽的开发提供理论依据。     

Comparative Study on the Antioxidant Activity of Peptides from Pearl Oyster(Pinctada martensii) Mantle Type V Collagen and Tilapia(Oreochromis niloticus) Scale Type Ⅰ Collagen

In this study, Pearl oyster mantle type V collagen(POMC) and tilapia scale type I collagen(TSC) were extracted and hydrolyzed by various proteases in order to obtain peptides. The antioxidant activity of the peptides was investigated by DPPH, hydroxyl radical scavenging experiments and a dynamic digestion model in vitro. The results show that there are significant differences in amino acid composition between POMC and TSC. The collagen peptides obtained from pearl oyster mantle(POMCP) by treating with alkaline protease exhibited higher antioxidant activity than that from tilapia scale(TSCP) treated with papaya protease, and both of them showed greater DPPH and hydroxyl radical scavenging activity than other peptides. After being separated via Sephadex G-25 chromatography, the M1 fraction isolated from POMCP, and the S1 fraction from TSCP with which both had higher molecular weights showed the strongest antioxidant activity than other fractions, and the M1 fraction exhibited stronger antioxidant activity than the S1 fraction in scavenging free-radicals and protecting cells from the oxidation damage. Furthermore, after treating the dynamic digestion system model in vitro, the DPPH and hydroxyl radical scavenging activity of the M1 fraction increased slightly. These results suggest that POMCP exhibits stronger antioxidant activity than TSCP, which means that PMOP may be a good candidate to be a potential natural antioxidant in the food-processing industry.     

Optimization of pectin extraction and antioxidant activities from Jerusalem artichoke

Jerusalem artichoke is an economic crop widely planted in saline-alkaline soil. The use of Jerusalem artichoke is of great significance. In this study, the response surface method was employed to optimize the eff ects of processing variables(extraction temperature, p H, extraction time, and liquid-tosolid ratio) on the yield of Jerusalem artichoke pectin. Under the optimal extraction conditions: p H 1.52, 63.62 min, 100°C and a liquid-to-solid ratio of 44.4 m L/g, the maximum pectin yield was predicted to be 18.76%. Experiments were conducted under these optimal conditions and a pectin yield of 18.52±0.90% was obtained, which validated the model prediction. The eff ects of diff erent drying methods(freeze drying, spray drying and vacuum drying) on the properties of Jerusalem artichoke pectin were evaluated and they were compared with apple pectin. FTIR spectral analysis showed no major structural diff erences in Jerusalem artichoke pectin samples produced by various drying treatments. The antioxidant activities of pectin dried by diff erent methods were investigated using in vitro hydroxyl and DPPH radical scavenging systems. The results revealed that the activities of spray dried pectin(SDP) and apple pectin(AP) were stronger than those of vacuum oven dried pectin(ODP) and vacuum freeze dried pectin(FDP). Therefore compared with the other two drying methods, the spray drying method was the best.     

Expression of the Phycoerythrin Gene of Gracilaria lemaneiformis （Rhodophyta） in E. coil and Evaluation of the Bioactivity of Recombinant PE

Phycoerythrin (PE) is one of the most important proteins involved in light capturing during photosynthesis in red algae. Its potential biological activities had gained wide concerns. In the present study, tumor cytotoxic and hydroxyl radical assay were preformed to detect the bioactivity of recombinant PE. Recombinant plasmids pGEX-PE and pBGL were transformed into E. coli BL21 to make two recombinant strains BEX (pGEX-PE) and BGL (pBGL). PE expressing in BEX (pGEX-PE) was validated by SDS-PAGE and Western blotting analysis. SDS-PAGE analysis indicated that the PE-GST fusion protein was mostly inclusion bodies. Specific expression of PE was confirmed by Western blotting analysis. The recombinant E. coli BEX (pGEX-PE) cells were collected and sonicated. The supernatants were reserved for the tumor cytotoxic experiments. The result of tumor cytotoxic assay indicated that the supernatants containing PE had the activity of inhibiting the growth of Hela cells and with the increase of protein concentration, the inhibiting rate increased from 37.31% to 63.26%, which showed significant difference from the control. Hydroxyl radical scavenging effect was tested with supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates treated with sonication and heating. For the sonication samples, the scavenging rates of the supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates were significantly higher than the negative control BL21(pGEX-4T) (P<0.02), and the scavenging rates increased slowly following the increase of the protein content. For the heating samples, except for the 0.2 mg mL⁻¹ BGL (pBGL) products, the scavenging effects of the supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates were stronger than that of negative control BL21(pGEX-4T). However, the effect intensity was not positively correlated with the increase of the protein concentration. Though a partially decreased hydroxyl radical scavenging activity was led by heating, the biological activity was still retained and conspicuous. This research showed that phycoerythrin protein expressing in E. coli has the potential medical and sanitarian value.     

Anti-oxidant and anti-inflammatory activities of ultrasonic-assistant extracted polyphenol-rich compounds from Sargassum muticum

Polypehnol is an important, potentially bioactive component of Sargassum muticum. In this study, ultrasonic assisted extraction of polyphenol-rich substances was performed using a 38% ethanol solution at a solid:liquid ratio of 1:30 at 68℃ for 32 min, determined by single-factor and response surface methodology(RSM) optimization. The content of polyphenol was 5.66 mg/g in the crude extract. Further extraction showed that the polyphenol mainly distributed in ethyl acetate(SKEE) and water phases(SKEW).The anti-oxidation test by electron spin resonance(ESR) spectrum showed that the SKEE had the strongest scavenging activity on DPPH(1,1-diphenyl-2-picrylhydrazyl) and alkyl radicals. SKEE was shown noncytotoxic but could inhibit the generation of cellular ROS, showing protective effects in H_2O_2 and AAPHinduced Vero cells and UV-B irradiated HaCaT cells. SKEE also significantly inhibited the release of NO of LPS-induced RAW 264.7 cells. Therefore, the polyphenol-rich extracts in ethanol and ethyl acetate showed excellent anti-oxidant and anti-inflammatory activities, which is beneficial to the development of high-value bio-substances.     

Expression of the Phycoerythrin Gene of Gracilaria lemaneiformis (Rhodophyta) in E. coli and Evaluation of the Bioactivity of Recombinant PE

Phycoerythrin (PE) is one of the most important proteins involved in light capturing during photosynthesis in red algae. Its potential biological activities had gained wide concerns. In the present study, tumor cytotoxic and hydroxyl radical assay were preformed to detect the bioactivity of recombinant PE. Recombinant plasmids pGEX-PE and pBGL were transformed into E.coli BL21 to make two recombinant strains BEX (pGEX-PE) and BGL (pBGL). PE expressing in BEX (pGEX-PE) was validated by SDS-PAGE and Western blotting analysis. SDS-PAGE analysis indicated that the PE-GST fusion protein was mostly inclusion bod- ies. Specific expression of PE was confirmed by Western blotting analysis. The recombinant E. coli BEX (pGEX-PE) cells were col- lected and sonicated. The supernatants were reserved for the tumor cytotoxic experiments. The result of tumor cytotoxic assay indi- cated that the supernatants containing PE had the activity of inhibiting the growth of Hela cells and with the increase of protein con- centration, the inhibiting rate increased from 37.31% to 63.26%, which showed significant difference from the control. Hydroxyl radical scavenging effect was tested with supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates treated with sonication and heating. For the sonication samples, the scavenging rates of the supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates were significantly higher than the negative control BL21(pGEX-4T) (P<0.02), and the scavenging rates increased slowly following the increase of the protein content. For the heating samples, except for the 0.2 mg mL-1 BGL (pBGL) products, the scavenging effects of the supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates were stronger than that of negative control BL21(pGEX-4T). However, the effect intensity was not positively correlated with the increase of the protein concentration. Though a partially de- creased hydroxyl radical scavenging activity was led by heating, the biological activity was still retained and conspicuous. This re- search showed that phycoerythrin protein expressing in E. coli has the potential medical and sanitarian value.     

Sulfated polysaccharides with antioxidant and anticoagulant activity from the sea cucumber Holothuria fuscogliva

Sea cucumber is a traditional nutritional food and medicinal resource with many bioactive components in China.Holothuria fuscogliva is a big sea cucumber with a rich of bioactive polysaccharides.To investigate the bioactivities of the polysaccharides from sea cucumber H.fuscogliva,we prepared the sulfated polysaccharides(HfP) from sea cucumber H.fuscogliva using a protease hydrolysis method.Antioxidant activities of HfP were investigated,including hydroxyl radical scavenging activity and superoxide radical scavenging activity.And,the anticoagulant activities of HfP were studied,including the activated partial thromboplastin time(APTT),prothrombin time(PT) and thrombin time(TT).The average molecular weight was 1 867.1 Da,with a sulfate content of 20.7%.In addition,the molar ratio of monosaccharide composition of HfP was Man:Rha:Glc A:Glc:Gal:Xyl:Fuc=0.083 6:0.437:0.134:0:1.182:0.748:1.It had a strong antioxidant activity,the hydroxyl and superoxide radical scavenging activity EC_(50) of HfP was 3.74 and 0.037 mg/mL,respectively.It also showed a good anticoagulant activity in our study.The APTT of HfP was much higher than that of heparin sodium,and the PT and TT of HfP was close to that of heparin sodium at a low concentration.Therefore,HfP shows a good antioxidant and anticoagulant activity and it may become a potential candidate of the natural antioxidant and anticoagulant and will have a good application future in health product or medicine industry.     

Effects of carboxymethyl-chitosan on wound healing in vivo and in vitro

Effects of carboxymethyl-chitosan with different molecular weights on wound healing were investigated in vivo and in vitro.A second degree burn model was performed in rats and the accelerative effects of carboxymethyl-chitosan on wound repair were observed.Contents of transforming growth factor(TGF)-β1,interleukin(IL)-6 and matrix metalloproteinase(MMP)-1 in wounds were determined by enzyme-linked immunosorbent assay(ELISA).In vitro study evaluated the influence of carboxy-methyl-chitosan on cytokines secretion of fibroblasts and macrophages.In vivo results showed that carboxymethyl-chitosan effec-tively accelerated the wound healing process in burned rats(P<0.05).Levels of TGF-β1,IL-6 and MMP-1 in carboxymethyl-chitosan groups were significantly elevated,compared with control group(P<0.05).In vitro results indicated that carboxymethyl-chitosan significantly promoted the proliferation of fibroblasts and stimulated its IL-8 and IL-10 secretion at different incubation time,but it did not affect collagen secretion of fibroblasts.Carboxymethyl-chitosan enhanced phagocytosis ability of macrophages,and in-creased its tumor necrosis factor(TNF)-α secretion.In conclusion,carboxymethyl-chitosan promoted wound healing by activating macrophages,accelerating fibroblasts growth and exerting considerable effects on the secretion of a series of cytokines.     

Recovery of astaxanthin from discharged wastewater during the production of chitin

In this paper, studies were carried out to extract astaxanthin from discharged wastewater during the production of chitin and to reveal the scavenging effect of the obtained pigment on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. Different ratios of dichloromethane/methanol (V/V) were used to extract astaxanthin. When the ratio of dichloromethane/methanol was 2:8 and the ratio between the mixed organic solvent (dichloromethane/methanol, 2:8, V/V) and wastewater was 1:1, the highest yield of pigment was obtained (8.4 mg/ 50 mL). The concentration of free astaxanthin in the obtained pigment analyzed by HPLC was 30.02%. The obtained pigment possessed strong scavenging ability on DPPH radical and IC50 was 0.84mg/ml.