oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 178 )

2018 ( 3538 )

2017 ( 3691 )

2016 ( 3920 )

Custom range...

Search Results: 1 - 10 of 171155 matches for " 赵谋明 "
All listed articles are free for downloading (OA Articles)
Page 1 /171155
Display every page Item
江蓠琼胶加工中碱处理的作用及机理

食品科学 , 1991,
Abstract: ?高温稀减法处理8份不同种类及不同产地的江蓠,所得琼胶的凝胶强度平均提高12.3倍,硫酸基含量平均减少67.0%,3.6—内醚半乳糖的含量平均提高26.1,凝固点和融点分别提高4.5℃及8.6℃.碱处理后江蓠藻体宏观上颜色明显变浅,同时藻体变得坚硬;微观结构上皮层明显变薄,外表变得凹凸不平,从里到外出现无数裂纹,髓部细胞的细胞壁,细胞膜部分出现破坏,形状不一,排列混乱而松散。
八种水果多酚的定量分析与抗氧化活性研究

- , 2017, DOI: 10.13982/j.mfst.1673-9078.2017.10.032
Abstract: 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。
The content of vitamin C and total phenolic content in peel, flesh, whole fruit and fruit juice of eight fruits were determined in this study. Phenolic profiles of eight fruits were determined by high performance liquid chromatography (HPLC), and their antioxidant activities were evaluated. The results showed that the content of vitamin C in eight fruits were in the order of guava > navel orange > pineapple = papaya > green apple = crown pear = kumquat = mango. Mango had the highest total phenolic content. Sixteen phenolic compounds were identified from eight fruits, and the content of chlorogenic acid, catechins, epicatechin, rutin, myricetin and phloridzin were higher. Eight fruits were divided into four categories in terms of the phenolic profiles: (1) navel orange; (2) mango; (3) kumquat; (4) green apple, crown pear, guava, pineapple and papaya. DPPH radical scavenging activities of the eight fruits were in a descending order as follows: mango > guava > green apple > crown pear = kumquat = navel orange = pineapple = papaya. Oxygen radical absorbance capacities decreased in the order of navel orange > guava > crown pear = mango > green apple = kumquat = pineapple = papaya. This study could provide the theoretical guidance for the development of fruit deep processing industry and functional food.
循环流体浸渍速冻工艺对鲻鱼贮藏品质的影响

- , 2016, DOI: 10.13982/j.mfst.1673-9078.2016.12.028
Abstract: 为探究循环流体浸渍速冻工艺对鲻鱼冻结过程及后期贮藏品质的影响,本文对比了经过-25 ℃循环流体浸渍速冻和-18 ℃风冷式冷柜直冻两种预处理后再置于-18 ℃冷柜中贮藏的鲻鱼样品,观察其冻结曲线及在0 d、3 d、6 d、9 d、14 d和30 d的保水性(解冻汁液流失率和蒸煮损失率),新鲜度(总挥发性盐基氮、TVB-N、感官评定和质构特性),油脂氧化(硫代巴比妥酸值,TBARS)与肌原纤维蛋白氧化(羰基含量、总巯基值和二聚酪氨酸含量)四项品质指标。实验表明:速冻组样品的各项指标均优于直冻组,理化品质下降程度低于直冻组。第30 d时,速冻组样品的解冻汁液流失率、蒸煮损失率分别为10.36%和10.16%(p<0.05);TVB-N值为11.40?10-2 mg/g,依然在新鲜范围内;油脂氧化与肌原纤维蛋白氧化程度远小于直冻组(p<0.05),TBARS值为0.14 mg MDA/kg,羰基值为6.52 nmol/mg蛋白,总巯基值为58.11 nmol/mg蛋白,二聚酪氨酸含量为8911.50±15.58 A.U.。
We investigated the use of circulated fluid impregnation (CFI) as a novel quick-freezing technique for Mullet and its impact on storage quality. Experimental Mullet fillet samples were subjected to -25 ℃ CFI treatment before storage at -18 ℃, while the control samples were directly stored at -18 ℃, for 0, 3, 6, 9, 14, and 30 d. The freezing curve was then monitored and the properties of Mullet after storage (up to 30 d) were also evaluated with regard to changes in 4 indicators. These included water holding capacity (drip loss rate and cooking loss rate), freshness (total basic-nitrogen [TVB-N], sensory evaluation, and texture), lipid oxidation (thiobarbituric acid reactive substances, TBARS), and myofibrillar protein oxidation (carbonyl content, total sulfhydryl content, and bityrosine content). The results indicated that samples from the experimental group were superior with regard to all indicators compared to the control group during the entire storage experiment; the decline in their physical and chemical qualities was also lower. By 30 d, the drip loss rate and cooking loss rate of the experimental group were 10.36% and 10.16%, respectively (p<0.05), while the TVB-N value was 11.40?10-2 mg/g, which was within the accepted range of freshness. In addition, the degree of lipid oxidation and protein oxidation in the experimental group was also significantly lower than that in the control group (p<0.05) with a TBARS value of 0.14 mg MDA/kg, carbonyl content of 6.52 nmol/mg protein, total sulfhydryl content of 58.11 nmol/mg protein, and bityrosine content of 8911.50±15.58 A.U..
SDE和HS-SPME法与GC-MS/O联用分析阳江豆豉的香气活性化合物

- , 2016, DOI: 10.13982/j.mfst.1673-9078.2016.5.040
Abstract: 采用同时蒸馏萃取法(SDE)和顶空-固相微萃取法(HS-SPME)结合气相色谱-质谱/嗅闻检测技术(GC-MS/O)深入研究阳江豆豉的香气成分,共鉴定出挥发性化合物174种。SDE法对高分子量、低挥发性物质,如呋喃酮、吡喃酮等,有良好的萃取效果;而HS-SPME法能萃取更多的高挥发性化合物,如小分子的酸和酯类。通过GC-O技术在两种方法的萃取物中共嗅闻到46个香气活性区域。其中9种共有化合物(2/3-甲基丁醛、2/3-甲基丁酸、3-甲硫基丙醛、苯乙醛、愈创木酚、3-羟基-2-甲基-4H-吡喃-4-酮和苯乙醇),以及香气强度较高(评分大于2.5分)的单方法检出化合物:SDE法4种(3-羟基-4,5-二甲基-2(5H)-呋喃酮、2-乙酰基-1-吡咯啉、2-丙烯基-3-甲基吡嗪和4-羟基-2,5-二甲基-3(2H)-呋喃酮)、SPME法1种(1-辛烯-3-醇),是阳江豆豉中的关键香气活性物质,对麦芽香、酸奶酪香、烤土豆香、花香、烟熏香、焦糖香和烤香等有贡献。
The aroma profiles of Yang jiang douchi were studied by simultaneous distillation extraction (SDE) and head space-solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry/olfactometry, and a total of 174 volatile compounds were identified. SDE is suitable for extraction of high-molecular weight and low-volatile substances such as furanones and pyrones, while SPME is effective for extracting high-volatile compounds such as small-molecule acids and esters. Using gas chromatography-olfactometry, 46 aroma-active regions were detected in the extracts by SDE and SPME. Among them, nine compounds [2/3-methylbutanal, 2/3-methylbutanoic acid, 3-(methylthio)propanal, phenylacetaldehyde, 2-methoxyphenol, 3-hydroxy-2-methyl-4H-pyran-4-one, and phenethyl alcohol] were identified in the extracts by both methods. Four compounds [sotolone, 2-acetyl-1-pyrroline, 2-allyl-3-methylpyrazine, and 4-hydroxy- 2,5-dimethyl-3(2H)-furanone] and one compound (1-octen-3-ol) with high aroma intensity were identified only by SDE and SPME, respectively. These compounds are key aroma-active substances that contribute to the malty, cheese-like, cooked potato-like, floral, smoky, caramel-like, and roasted-like smells of Yang jiang douchi.
纳豆菌液态发酵谷物产纳豆激酶及发酵产物抗氧化活性研究

- , 2018, DOI: 10.13982/j.mfst.1673-9078.2018.2.013
Abstract: 本文研究了纳豆菌液态发酵时间对纳豆菌生物量、蛋白酶酶活、纳豆激酶酶活的影响。在此基础上,研究添加四种谷物(糙薏仁、玉米、荞麦和糙米)对纳豆菌液态发酵产蛋白酶酶活、纳豆激酶酶活、谷物总酚迁移率、总酚残留率以及发酵产物抗氧化活性的影响。结果表明:添加糙米和荞麦可显著促进纳豆菌产蛋白酶(2444.19、1813.71 U/mL)、纳豆激酶(719.67、681.38 U/mL),且以荞麦为底物所产发酵产物的谷物总酚迁移率最高(0.64 mg/g干谷物)、抗氧化活性最强(30.37 μmol trolox equiv/mL);采用浸泡蒸煮处理四种谷物、延长发酵时间可显著提高其发酵产物的蛋白酶酶活、纳豆激酶酶活、谷物总酚迁移率以及抗氧化活性。采用浸泡蒸煮处理荞麦,利用纳豆菌液态发酵其48 h,可制备富含纳豆激酶、谷物多酚、肽类物质且具有强溶栓、抗氧化活性的功能性食品。
The effects of Bacillus natto liquid fermentation time on biomass and enzyme activities of nattokinase and protease were studied. In addition, the effects of four grains (brown adlay, corn, buckwheat, brown rice) on enzyme activities of protease and nattokinase, migration ratios and residue ratios of grain total phenols, and antioxidant activities of fermentation products by Bacillus natto liquid fermentation were also evaluated. The results showed that buckwheat and brown rice could significantly promote the enzyme activities of protease (2444.19, 1813.71U/mL) and nattokinase (719.67, 681.38 U/mL). The fermentation products obtained by Bacillus natto liquid fermentation with buckwheat possessed the highest of migration ratio of total phenols (0.64 mg/g dry grain) and exhibited the strongest antioxidant activity (30.37 μmol trolox equiv/mL). The enzyme activities of protease and nattokinase, migration ratios and residue ratios of grain phenols and antioxidant activities of fermentation products could be significantly improved by soaking and cooking four grains and extending fermentation time. The functional food rich in nattokinase, grain phenolics, and peptides possessed strong thrombolytic and antioxidant activity could be obtained by Bacillus natto liquid fermentation for 48 h with buckwheat pretreated by soaking and cooking.
10种市售鸡肉香精的挥发性风味化合物分析

- , 2016, DOI: 10.13982/j.mfst.1673-9078.2016.9.040
Abstract: 为了研究市售鸡肉香精的香气组成,本文通过顶空-固相微萃取(HS-SPME)与气相色谱-质谱联用(GC-MS)分析10种商业样品,共检出挥发性化合物131种。其中,萜类、醛类和含硫化合物检出种类最多,分别有25、28和29种,另外,检出化合物还包括酯、呋喃(酮)、酮、吡嗪、酚、醇、酸类等。不同香精其香气组成差异较大,以香气组成最复杂的香精为代表,首次通过气相色谱-嗅闻检测技术(GC-O)剖析鸡肉香精的香气组成,共检出香气活性化合物30种。其中代表性香气活性物质及其主要香型分类如下:主体肉香(甲基(2-甲基-3-呋喃基)二硫醚、甲基糠基二硫醚)、特征脂肪香((E,E)-2,4-庚二烯醛、(E,E)-2,4-壬二烯醛)、葱蒜香(二甲基三硫、二烯丙基二硫醚)、辛香(4-甲氧基苯甲醛、4-乙基愈创木酚)、烘烤香(3-甲硫基丙醛)、甜香(2,4-二氢-2,5-二甲基-3(2H)-呋喃酮、4-羟基-2,5-二甲基-3(2H)-呋喃酮)、酸香(乙酸)和奶香(2,3-丁二酮)。
In order to study the aroma compositions of commercial chicken flavors, headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used to analyze ten commercial products. A total of 131 compounds were identified with various types of the same compound, such as sulfur-containing compounds (29), terpenes (28), and aldehydes (25), followed by esters, furan(one)s, ketones, pyrazines, phenols, acids, and alcohols. Significant differences in the aroma composition were observed among these different chicken flavors. The flavor with the most complex aroma composition was used as the representative sample to study the aroma profiles of chicken flavor using gas chromatography-olfactometry (GC-O), and thirty aroma-active compounds were detected. The representative aroma-active compounds and their corresponding aroma types were classified as follows: meat-like flavors (2-methyl-3-furyl) disulfide and 2-[(methyldithio) methyl] furan), characteristic fat flavors ((E,E)-2,4-heptadienal and (E,E)-2,4-nonadienal), alliaceous flavor (dimethyl trisulfide and diallyl disulfide), spicy flavor (4-methoxybenzaldehyde and 4-ethyl-2-methoxyphenol), roasted flavor (3-(methylthio) propanal), caramel-like flavor (2,4-dihydro-2,5-dimethyl-3(2H)-furanone and 2,5-dimethyl-4-hydroxy-3(2H)-furanone), sour flavor (acetic acid), and milk flavor (2,3-butanedione).
一株深海来源苏云金芽孢杆菌SWJS07所产蛋白酶的分离纯化及性质研究

- , 2015, DOI: 10.13982/j.mfst.1673-9078.2015.8.027
Abstract: 利用超滤、硫酸铵盐析、DEAE Sepharose Fast Flow阴离子交换柱层析、Sephadex G-75分子筛柱层析对一株南海深海来源菌苏云金芽孢杆菌(B. thuringiensis)SWJS07所产蛋白酶进行分离纯化,纯化后经SDS-PAGE鉴定达到电泳纯,相对分子质量为37.0 kDa,酶的比活力提高了6.39倍,回收率为37.14%。研究其酶学性质表明,该蛋白酶最适催化温度为55 ℃,在30 ℃~45 ℃下稳定性较高,保温300 min残留酶活在80%以上;最适pH 6.5,在pH 6.0~9.0蛋白酶稳定,4 ℃放置24 h残留酶活在80%以上;2 mM Ca2+、Mn2+对蛋白酶有不同程度的激活作用,而Hg2+、Cd2+、Al3+则强烈地抑制蛋白酶活;当在蛋白酶中添加2 mM Ca2+、Mn2+时,其最适催化温度分别为60 ℃和55 ℃,蛋白酶活分别提高了32.86%和28.35%,60 ℃保温30 min相对酶活基本保持不变,与纯酶(相对酶活残留21.02%)相比蛋白酶的热稳定性显著提高;EDTA-Na2可强烈抑制蛋白酶活,推测该蛋白酶属于金属蛋白酶。
The protease produced by the marine strain B. thuringiensis SWJS07 was purified to homogeneity by ultrafiltration, ammonium sulfate precipitation, anion-exchange chromatography (DEAE-Sepharose Fast Flow) and gel filtration chromatography (Sephadex G-75), with a 6.39-fold increase in specific activity and 37.14% recovery and the molecular weight was estimated to be 37.0 kDa on SDS-PAGE. The optimal temperature and pH for the purified protease were determined to be 55 ℃ and pH 6.5. The protease was highly stable from 30 ℃ to 45 ℃ and between pH 6.0 and 9.0 and it was activated by Ca2+and Mn2+, while Hg2+, Cd2+, Al3+ had a strong inhibitory effect. The optimal temperature were 60 ℃ and 55 ℃ in the presence of 2 mM Ca2+and Mn2+, and the activity were increase by 32.86%, 28.35%, respectively. Meanwhile, thermostability of the protease was enhanced by Ca2+ and Mn2+. In the presence of 2 mM Ca2+and Mn2+, the activity of the protease were retained unchanged after heating for 30 min at 60 ℃, however, it retained 21.02% of its initial activity in the absence of them. It was strongly inhibited by EDTA-Na2, indicating that the protease may be metalloprotease.
不同HLB值的表面活性剂对核桃仁酶解特性的影响

- , 2016, DOI: 10.13982/j.mfst.1673-9078.2016.7.018
Abstract: 本文主要研究了表面活性剂不同HLB值对水酶法提取核桃油和制备抗氧化肽过程中油提取率、酶解清液析出率、乳化层形成率、酶解清液还原力和蛋白回收率的影响,并通过测定酶解清液的肽分子量分布和乳化层的粒径分布及其组成进一步探讨了其作用机理,研究发现:随着表面活性剂HLB值的逐渐增大,油提取率逐渐降低,乳化层形成率及酶解清液中>5000 u和>3000 u的肽段含量逐渐升高,而酶解清液析出率和蛋白质回收率则呈现出先减小后增大最后又减小的趋势。与空白相比,表面活性剂HLB值为1.0时,核桃油提取率可提高5%左右;表面活性剂HLB值为13.5时,可显著解析界面蛋白和多肽,增大乳化层中的脂肪球粒径,显著提高酶解清液中的蛋白回收率,且不会对核桃肽的抗氧化活性造成显著影响。
The effects of the hydrophile-lipophile balance (HLB) value of surfactants on the oil extraction rate, enzymatic hydrolysate supernatant yield, emulsified layer formation rate, protein recovery, and protein reducing power of walnut hydrolysates were examined in this research. And the molecular weight distribution of the peptides in the enzymatic hydrolysate, the droplet size distributions in the emulsified layer, and the composition of the emulsified layer were determined to further investigate the underlying mechanisms. The results showed that the oil extraction rate decreased gradually as the HLB value increased. The emulsified layer formation rate and the contents of proteins or peptides with molecular weights higher than 5000 or 3000 Da increased gradually as the HLB value increased. In addition, the yields of enzymatic hydrolysate supernatants and proteins initially tended to decrease, then increased, and finally decreased. Compared with the blank control, the oil extraction rate was increased by five percent at an HLB value of one. When the HLB value was 13.5, the contents of surface proteins and peptides in the emulsified layer decreased significantly, the particle sizes of the fat globules in the emulsified layer increased, and protein recovery in the enzymatic hydrolysate supernatant improved significantly. However, the antioxidant activity of the walnut hydrolysate was not significantly altered.
产耐盐蛋白酶深海细菌的分离鉴定

- , 2015, DOI: 10.13982/j.mfst.1673-9078.2015.3.009
Abstract: 本文采用高盐富集、复筛发酵及耐盐稳定性实验的方式,从深海海泥中筛选产耐盐蛋白酶的深海海洋细菌。从深海海洋微生物中共筛选出25株耐盐菌,在这25株菌株中有14株在酪蛋白平板上能产生较大的水解圈;通过发酵复筛及耐盐稳定性实验,筛选得到一株酶活性能高且耐盐稳定性好的菌株,将其编号为SWJSS3;对菌株SWJSS3进行16S rDNA的鉴定并初步研究了盐浓度对产酶情况和酶稳定性的影响。菌株SWJSS3在0~10% (m/V)的盐浓度条件下均能生长,在0~10%的盐浓度下,菌液OD600的吸光值范围为0.08-1.98;通过发酵复筛其所产生的蛋白酶酶活在盐浓度为1%时达最高,为233.56±2.16 U/mL;所产蛋白酶在终浓度为15% (m/V)的NaCl溶液下,混匀4 ℃保存1 h,残余酶活为初始酶活的40.70±2.06%,继续存放一段时间到第9 h,酶活基本保持不变;通过16S rDNA鉴定其为铜绿假单胞菌,与Pseudomonas aeruginosa RP28 16S rDNA的相似性达到99%以上。
This study was aimed at screening deep-sea bacteria that produce salt-tolerant proteases from deep-sea mud samples based on high-salt accumulation, fermentation rescreening, and salt-tolerant stability tests. Twenty-five strains of deep-sea marine microorganisms were selected, 14 of which demonstrated an increase in hydrolysis cycles on casein plates. A strain with high enzyme activity and salt stability was obtained based on fermentation rescreening and a salt-tolerance test, and was labeled as SWJSS3. Strain SWJSS3 was identified using 16S rDNA and a preliminary study on the effects of salt concentration on its protease yield and stability was conducted. The strain was able to grow in medium with salt concentrations between 0% and 10% and an OD600 of the bacterial suspension ranging from 0.08 to 1.98. The activity of proteases produced by SWJSS3 was maximal for a 1% salt concentration in the fermentation rescreening (233.56 ± 2 U/mL). After treatment with 15% (final concentration) sodium chloride solution at 4 °C for 1 h, the enzyme activity decreased to 40.70 ± 2.06% of the initial enzyme activity, but remained stable for up to 9 h. strain SWJSS3 was identified as Pseudomonas aeruginosa, exhibiting 99% 16S rDNA sequence similarity to P. aeruginosa RP28.
山苦茶多糖结构表征及抗氧化活性研究

- , 2015, DOI: 10.13982/j.mfst.1673-9078.2015.7.011
Abstract: 本文从山苦茶中提取得到两个多糖组分水溶性多糖(MOWP)和碱溶性多糖(MOAP),得率分别为6.00%和3.07%。采用高效凝胶渗透色谱法(GPC)分别测定了MOWP和MOAP的分子量分布;采用PMP柱前衍生-高效液相色谱法(HPLC)分别测定了MOWP和MOAP的单糖组成;采用甲基化-气相色谱质谱法(GC/MS)研究了MOWP和MOAP的糖苷键连接方式。此外,采用DPPH?清除法、还原力法以及氧自由基吸收(ORAC)法,评价了MOWP和MOAP的体外抗氧化活性。结果表明:MOWP分子量分别为906 kDa和49 kDa,MOAP的分子量为95 kDa。木糖、半乳糖及葡萄糖构成了酸性多糖MOWP的骨架结构,而酸性多糖MOAP由甘露糖、木糖及半乳糖构成骨架。MOWP和MOAP中→3)-Xylf-(1→、→3)-Galp-(1→以及→3)-Glcp-(1→残基含量均较高。MOWP和MOAP均有一定的抗氧化能力,MOWP清除DPPH?的能力较强,MOAP具有较强的还原能力和氧自由基吸收能力。
A water-soluble polysaccharide (MOWP) and an alkali-soluble polysaccharide (MOAP) were isolated from Mallotus oblongifolius. The MOWP and MOAP yields were 6.00% and 3.07%, respectively. The molecular weights of the MOWP and MOAP were determined by a high performance gel permeation chromatography assay. The molecular weights of the MOWPs were 906 kDa and 49 kDa, and the molecular weight of the MOAP was 95 kDa. The monosaccharide composition was determined by a pre-column derivatization assay. Based on the monosaccharide composition analysis, the MOWP was mainly comprised of glucose, galactose, and xylose. MOAP was mainly comprised of mannose, galactose, and xylose. The glycosidic bonds of MOWPs and MOAPs were determined by a methylation assay. The branched MOWPs and MOAPs were composed mainly of →3)-Xylf-(1→, →3)-Galp-(1→ and →3)-Glcp-(1→ in different ratios. MOWPs and MOAPs exhibited moderate antioxidant capacities. MOWPs showed better DPPH scavenging activity than did MOAPs. MOAPs showed better reducing power and oxygen radical absorbance capacity than did MOWPs.
Page 1 /171155
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.