葛仙米藻胆蛋白粗提物、藻蓝蛋白和藻红蛋白的体外抗氧化活性比较研究

在体外模型上,对人工养殖的葛仙米藻胆蛋白粗提物、藻蓝蛋白和藻红蛋白的抗氧化活性进行比较研究。通过考察羟基自由基清除能力、超氧阴离子自由基清除能力、脂质过氧化抑制能力,对葛仙米中藻胆蛋白粗提物、藻蓝蛋白和藻红蛋白的抗氧化活性进行评价。体外抗氧化作用结果显示藻胆蛋白、藻红蛋白和藻蓝蛋白都有明显的抗氧化作用,但作用方式和抗氧化程度也有不同,在羟基自由基清除试验中,抗氧化活性由强到弱依次为藻胆蛋白藻蓝蛋白藻红蛋白;在超氧阴离子清除试验中藻红蛋白≧藻蓝蛋白藻胆蛋白;在抑制脂质过氧化试验中藻红蛋白藻胆蛋白藻蓝蛋白。人工养殖的葛仙米中藻蓝蛋白、藻红蛋白及藻胆蛋白粗提物具有很好的体外抗氧化活性,但三者抗氧化方式略有差异。     

3种处理方式对葛仙米藻胆蛋白清除超氧阴离子自由基能力的影响

主要研究反复冻融、溶剂、pH值等对葛仙米藻胆蛋白清除超氧阴离子自由基能力的影响,并探讨藻胆蛋白的模拟胃肠液降解产物对超氧阴离子自由基清除能力的变化情况。结果发现反复冻融不会影响葛仙米藻胆蛋白清除超氧阴离子自由基的能力,磷酸缓冲液可提高藻胆蛋白清除超氧阴离子自由基的能力。pH 5.6和pH 7.3浸提物清除超氧阴离子自由基的能力差异不显著,但pH 8.1浸提液略优于其他两种。随着处理时间延长,模拟肠液消化产物清除超氧阴离子自由基能力逐渐增强,模拟胃液消化产物却逐渐下降。     

葛仙米藻红蛋白体外抗活性氧自由基作用的研究

葛仙米以其资源稀少、营养价值丰富,独特的生物活性和药理作用而引起人们广泛地关注。为探讨葛仙米中的生物活性成分,本文以野生葛仙米藻红蛋白为研究对象,在系统研究葛仙米藻红蛋白的提取、分离和纯化的基础上,采用微弱化学发光法,研究了葛仙米藻红蛋白清除氧自由基的能力。结果表明:清除氧自由基的能力为:粗提物>藻红蛋白>藻蓝蛋白;葛仙米藻红蛋白清除氧自由基的能力为:H2O2自由基的清除率>·OH自由基的清除率>O2·自由基的清除率。     

葛仙米藻蓝蛋白抗氧化作用研究

通过非脂质体系抗氧化实验、体外抗氧化实验研究了葛仙米藻蓝蛋白的抗氧化能力。结果表明:葛仙米藻蓝蛋白对清除O2·、·OH自由基和H2O2具有较好的量效关系。在体外反应体系中,葛仙米藻蓝蛋白能显著地降低MDA生成和血和肝中过氧化物的含量,起到保护细胞膜和红血球的作用。显示葛仙米藻蓝蛋白对小鼠肝线粒体损伤具有保护作用,并能显著影响血浆的抗活性氧能力。     

反复冻融增强葛仙米藻胆蛋白抗氧化特性研究

研究反复冻融处理对葛仙米藻胆蛋白抗氧化特性的影响,测定其对抗氧化活性和对H2O2诱导的红细胞溶血和脂质过氧化的抑制作用。结果发现:经过反复冻融处理的葛仙米藻胆蛋白以pH7.3的50mmol/L的磷酸氢二钾-氢氧化钠为溶剂溶解的样品对ABTS+.的抗氧化活性和对H2O2诱导的红细胞溶血和脂质过氧化抑制作用强于其他处理,同时对铁离子的还原能力也较强,主要原因是反复冻融处理增加了葛仙米藻胆蛋白的溶出量,改变其中藻蓝蛋白和藻红蛋白的比例关系。     

干燥方式对四角蛤蜊酶解物功能特性和 抗氧化活性的影响

目的比较不同干燥方式对四角蛤蜊木瓜蛋白酶酶解物功能特性和抗氧化活性的影响。方法采用冷冻干燥和喷雾干燥2种方式对四角蛤蜊木瓜蛋白酶酶解物进行干燥处理,比较其功能特性和抗氧化活性。结果冷冻干燥(freezing drying,FD)组的蛋白含量(49.56%)高于喷雾干燥(spray drying,SD)组(44.31%),2组均含有17种氨基酸,总氨基酸含量之间无显著性差异。两者均具有一定的抗氧化能力,FD组的DPPH?清除能力和还原能力均优于SD组,其IC50和AC0.5值分别为3.02、4.52 mg/mL和3.55、4.03 mg/mL。FD组和SD组颜色差异显著,且FD组的溶解性、起泡性和泡沫稳定性均好于SD组。结论 FD组的功能特性和抗氧化活性均优于SD组,四角蛤蜊酶解物采用真空冷冻干燥效果更好。     

葛仙米藻胆蛋白和藻蓝蛋白对S180荷瘤小鼠肿瘤生长的影响及其作用机制

目的:对人工养殖的葛仙米藻胆蛋白和藻蓝蛋白在S180荷瘤小鼠肿瘤生长的影响及作用机制研究。方法:通过考察S180荷瘤小鼠肿瘤体积、小鼠脏器指数和肿瘤组织切片观察,对葛仙米中藻胆蛋白、藻蓝蛋白的体内抗肿瘤活性进行评价,并初步研究了其作用机制。结果:体内抗肿瘤作用结果显示,葛仙米藻胆蛋白12.5、25、50 mg/kg剂量组对小鼠肉瘤S180的抑瘤率分别为11.19%、20.14%、37.65%。葛仙米藻蓝蛋白12.5、25、50 mg/kg剂量组对小鼠肉瘤S180的抑瘤率分别为19.74%、35.00%、52.06%。藻蓝蛋白能够明显促进抑癌蛋白P53和促凋亡蛋白Bax的表达,抑制凋亡抑制蛋白Bcl2的表达。结论:葛仙米藻蓝蛋白高剂量组可显著减少S180肉瘤细胞的增殖,葛仙米藻蓝蛋白低、中剂量和葛仙米藻胆蛋白高剂量也有一定的抑制作用,人工养殖的葛仙米中藻胆蛋白和藻蓝蛋白具有较好的体内抗肿瘤活性。     

喷雾冷冻干燥对鸡蛋清蛋白结构和特性的影响

为了探究喷雾冷冻干燥(Spray freeze drying,SFD)对鸡蛋清蛋白结构及功能特性的影响,将其与喷雾干燥(Spray drying,SD)蛋清粉进行对比,并通过质构仪、差示扫描量热(D S C)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)、低场核磁共振(LF-NMR)等对其结构及特性进行测定。结果表明:SFD粉的变性温度比SD粉低了15.7℃,表面巯基含量低42.40%;SFD粉的α-螺旋和β-折叠结构比例大,分子结构更有序,蛋白聚集程度小,从而使其乳化特性得到改善;SEM分析表明,SFD粉呈大孔隙颗粒网络结构,溶解度增大。两种蛋清粉溶解度随pH的升高均呈先下降后上升的趋势,SFD粉溶解性和乳化性明显高于SD粉(P<0.05),凝肢硬度和束缚水含量显著低于S D粉(P<0.05),保水性差,两者的起泡性无显著差异。综上所述:与SD粉蛋白相比,SFD粉蛋白在结构和部分功能特性方面发生了显著变化,尤其在溶解度和乳化特性方面更具优势。     

真空冷冻干燥对菊花多酚含量及其抗氧化活性的影响

以4种菊花(金丝皇菊、贡菊、雏菊、杭白菊)为原料,研究真空冷冻干燥对其多酚含量及抗氧化活性的影响。结果表明,真空冷冻干燥后,菊花总酚含量显著增加,其中雏菊的总酚含量增加率最高(增加了2.525倍);真空冷冻干燥后,除清除ABTS~+·能力差异不显著外,其清除DPPH·能力、铁还原能力以及ORAC变化显著,说明真空冷冻干燥对菊花多酚的抗氧化活性有较大影响。     

葛仙米藻胆蛋白提高小鼠免疫功能的研究

研究葛仙米藻胆蛋白对昆明小鼠的免疫增强活性。分别以100、300、500 mg/（kg·d）的葛仙米藻胆蛋白溶液剂量对小鼠连续灌胃30 d。然后分别对腹腔巨噬细胞吞噬率、自然杀伤（natural killer,NK）细胞活性,T淋巴细胞增殖、细胞因子、抗体、迟发型超敏反应（delayed type hypersensitivity,DTH）等免疫参数进行测定。结果表明：葛仙米藻胆蛋白可以提高腹腔巨噬细胞吞噬率、NK细胞活性、T淋巴系统增殖以及血清中白细胞介素（interleukin-2,IL-2）和IL-4细胞因子水平。同时葛仙米藻胆蛋白处理组的小鼠DTH显著高于对照组,表明葛仙米藻胆蛋白是一种潜在的免疫增强剂。     

乳酸钙对牛肉糜色泽稳定性的影响

为研究乳酸钙对牛肉糜色泽稳定性的影响,将牛背最长肌绞碎成肉糜,分别添加0.1%、0.3%、0.5%的乳酸钙溶液,研究在(4±1)℃的冷藏条件下,肉糜肉色稳定性、色素含量、脂肪氧化及高铁肌红蛋白还原酶活性随时间的变化。结果表明：在7d的贮藏期内,添加不同质量分数乳酸钙均可有效抑制高铁肌红蛋白的生成和脂肪氧化的发生,并显著提高高铁肌红蛋白还原酶活性和肉色稳定性,但会使肉糜L*值显著降低(P＜0.05)。其中0.3%的乳酸钙对稳定肉色有显著作用,护色效果明显。     

肌肽对牛肉糜肉色及脂肪氧化的影响

在牛背最长肌中添加肌肽(C_9H_(14)N_4O_3),研究在4±1℃冷藏条件下,不同浓度(0.05%、0.1%、0.5%、1.0%)肌肽对牛肉肉糜高铁肌红蛋白(MetMb)还原酶活性、色素含量、脂肪氧化及肉色稳定性的影响.结果表明:在7d的贮藏期内,添加不同浓度肌肽均可有效抑制肉糜MetMb含量上升、提高高铁肌红蛋白还原酶活性,并与无添加组有显著性差异(P<0.05),0.1%、0.5%浓度肌肽对抑制脂肪氧化、稳定肉色有显著作用,护色效果较理想     

Antioxidative/Antimicrobial effects of galangal and alpha-tocopherol in minced beef

The antioxidant and microbial stabilities of galangal (Alpinia galanga) extract in raw minced beef were examined at 4 +/- 1 degree C. Raw minced beef containing galangal extracts (0 to 0.10%, wt/wt) were prepared. Lipid oxidation during refrigerated storage was assessed by monitoring malonaldehyde formation, using the thiobarbituric acid reactive substances method. In minced beef, added galangal extract improved oxidative stability. Galangal extract at higher concentrations of 0.05% and 0.10% (wt/wt) were also found to extend the shelf-life of minced beef. Addition of alpha-tocopherol (0.02%, wt/wt) to galangal extract (0.05%, wt/wt) were observed to increase the oxidative but not the microbial stability of minced beef during the storage of 7 days. Galangal extract may prove useful in inhibiting lipid oxidation and increasing microbial stability of minced meat.     

Effects of calcium salts on beef longissimus quality

The objective of this research was to evaluate the effects of injection marination with calcium salts on beef longissimus quality traits. Strip loins were injected (11% by weight) with distilled water or a 0.1, 0.2, or 0.3 M solution of calcium ascorbate, calcium chloride, or calcium lactate. Non-injected loins served as controls. Visual and instrumental color evaluations indicated that calcium ascorbate accelerated myoglobin oxidation, and increasing molar concentration of any calcium salt caused faster (P<0.05) discoloration. Aerobic microbial plate counts were lower (P<0.05) for treatments containing calcium lactate than those with calcium chloride or calcium ascorbate. Calcium ascorbate inhibited lipid oxidation whereas calcium lactate and calcium chloride appeared to be pro-oxidants of lipid oxidation. No differences for Warner-Bratzler shear force or sensory panel tenderness were found among the calcium salts; however, 0.3 M treatments had lower shear values and were judged more tender than 0.1 M treatments. Calcium ascorbate and calcium chloride treatments resulted in less (P<0.05) beef flavor and more (P<0.05) off-flavors than calcium lactate treatments. In addition, 0.1 M treatments had higher (P<0.05) beef flavor scores while 0.3 M treatments had higher (P<0.05) off-flavor scores. Considering the effects on color life, microbial inhibition, shear force, and sensory traits, we recommend injecting beef longissimus with a 0.1 M solution of calcium lactate to enhance both uncooked and cooked quality.     

洋葱皮乙醇提取物对冷却牛肉颜色、脂质和蛋白质氧化稳定性的影响

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

The combined effect of antioxidants and modified atmosphere packaging on protein and lipid oxidation in beef patties during chill storage

Effect of rosemary extract and ascorbate/citrate (1:1) in combination with modified atmosphere packaging (100% N(2), 80% O(2)/20% N(2)) on protein and lipid oxidation in minced beef patties during storage in the dark for up to 6 days at 4°C was investigated. A high level of oxygen in the packaging atmosphere was found to increase both lipid and protein oxidation during storage as evaluated by TBARS analysis of secondary lipid oxidation products and by 2,4-dinitrophenylhydrazine derivatization of protein carbonyls. Both antioxidant systems tested were found to inhibit lipid oxidation but not protein oxidation. In contrast, ascorbate/citrate was found to promote protein oxidation. Rosemary extract was found to regenerate or protect α-tocopherol whereas the packaging atmospheres had no effect on α-tocopherol stability. In high oxygen atmospheres both antioxidants protected the fresh red meat colour with ascorbate/citrate being more efficient than the rosemary extract, whereas no effect of antioxidant on meat colour was found in beef patties stored in 100% nitrogen.     

Factors in Various Fractions of Meat Homogenates That Affect the Oxidative Stability of Raw Chicken Breast and Beef Loin

ABSTRACT:  The fractions of meat homogenates were analyzed to find the factors that determine the susceptibility of raw chicken breast and beef loin to lipid oxidation. The fractions used in this study were meat homogenate, precipitate, and supernatant of homogenate after centrifugation, and high and low molecular weight fractions from the supernatant. Chicken breast showed greater oxidative stability than beef loin during 10-d storage ( P < 0.05). All fractions from chicken breast showed lower amounts of free ionic iron and myoglobin and higher total antioxidant capacity (TAC) than those from beef loin during storage. The TAC level of chicken breast maintained during storage. This suggested that the oxidative stability of chicken breast was ascribed to high, stable total antioxidant capacity with low level of catalysts for lipid oxidation. The water-soluble high molecular weight fraction, which contained myoglobin, was responsible for the high lipoxygenase-like activity and lipid oxidation potential (LOP) in beef loin. TAC in all fractions from beef loin decreased during storage. This suggested that high myoglobin content in beef loin caused the imbalance between pro- and antioxidant factors leading to the high susceptibility of beef loin to lipid oxidation. Myoglobin served a major source of catalysts, ferrylmyoglobin, hematin, and/or free ionic iron, for lipid oxidation.     

宰后牛肉色泽稳定性及其影响因素

介绍了宰后影响牛肉色泽稳定性的主要因素及其机理,肌红蛋白的氧化状态是决定鲜肉产品的最主要因素,高铁肌红蛋白还原酶活力对于肌红蛋白氧化状态及肉色稳定性的影响最大,而在宰后储藏过程中各种内源性抗氧化成分对肉色稳定具有重要作用.并建议引入体外孵化和预测模型等相关研究方法.关于影响因子的精确研究对提高肉品色泽品质具有重要意义.     

Evaluation of cholesterol and lipid oxidation in raw and cooked minced beef stored under oxygen-enriched atmosphere

Oxygen-enriched modified atmosphere packaging (MAP) represents an important means to stabilize meat colour but may lead to an increase in lipid oxidation, influencing the acceptability and safety of the product. In this work, the effect on cholesterol and lipid susceptibility to oxidation was investigated in commercial minced beef held under MAP (80% O(2)/20% CO(2)). Cholesterol oxidation products (COPs), peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were determined, before and after pan frying, at 1, 8 and 15 days since packaging under refrigerated storage (3-4°C). 7α-Hydroxycholesterol, 7β-hydroxycholesterol and 7-ketocholesterol were the more abundant COPs identified. COPs significantly increased in raw beef during storage: after 1, 8 and 15 days since packaging COPs were at the levels of 10.4, 30.7 and 60.5μg/g of fat, respectively. Cooking did not affect cholesterol oxidation in freshly packaged minced beef but led to a rise in COPs amount with respect to raw muscle after 8 and 15 days of storage. The trend in cholesterol oxidation reflected the progressive increase in lipid peroxidation rate brought by MAP conditions.     

Effects of pyruvate on lipid oxidation and ground beef color

Our overall objective was to better understand the effects of added pyruvate on enhanced beef color stability. The 2 possible mechanisms assessed were the role of pyruvate in lipid oxidation and direct interaction between pyruvate and beef myoglobin. Microsomes were incubated with pyruvate at pH 5.6, 25 °C, and lipid oxidation was measured hourly for 3 h. Bovine oxymyoglobin at pH 5.6 was incubated with pyruvate and used to quantify both redox stability (metmyoglobin formation) and pyruvate-myoglobin adduction using mass spectrometry analysis. Surface color and lipid oxidation were measured on ground beef patties stored for 6 d in polyvinyl chloride over-wrap (PVC) or high oxygen. Addition of pyruvate to microsomes decreased lipid oxidation compared with controls (P < 0.05). Conversely, no effect on myoglobin was observed (no changes in redox stability and no peaks corresponding to pyruvate were observed; P > 0.05). However, pyruvate increased color stability and decreased lipid oxidation of ground beef patties packaged in PVC and high oxygen. Pyruvate decreased nitric oxide metmyoglobin-reducing capacity and oxygen consumption of patties compared with controls (P < 0.05). This research suggests that pyruvate may improve beef color stability primarily through its antioxidant effect on lipids. Practical Application: Discoloration of meat often results in significant revenue loss. This study suggests that pyruvate can improve the color stability of patties packaged in high oxygen and PVC primarily through its antioxidant effect on lipids.