企鹅珍珠贝肉蛋白酶解及酶解产物的抗氧化活性

用水解蛋白酶、复合蛋白酶、中性蛋白酶和风味蛋白酶对企鹅珍珠贝蛋白进行水解,以酶解液中的氨基态氮及风味为指标,确定风味蛋白酶为水解企鹅珍珠贝蛋白的最适蛋白酶,单因素及正交实验确定风味蛋白酶的最佳水解条件为:加酶量0.8%、温度55℃、起始p H6.0、固液比1∶1.0、酶解6h后的氨基酸态氮为3.65g/100m L。抗氧化实验表明,酶解产物具有较强的羟自由基、超氧阴离子自由基、DPPH自由基抑制及还原能力。研究结果将为企鹅珍珠贝肉的开发提供参考。     

企鹅珍珠贝肉酶解产物的制备及其醒酒作用的初步研究

以企鹅珍珠贝肉为研究对象,通过不同种类的蛋白酶对其进行水解,获得具有醒酒效果的酶解产物。通过比较不同酶解产物水解度、蛋白回收率及其与酶解产物灌胃小鼠后血液中酒精浓度的相互关系,选择具有显著效果的酶解产物并对其主要成分进行分析。企鹅珍珠贝酶解产物具有一定的促进小鼠体内酒精代谢功能。中性蛋白酶酶解产物效果最好,水解度为19.8%的酶解产物能使血液中酒精浓度降低32.4%,经测定其含有大量糖原、牛磺酸、甜菜碱等醒酒功能因子。企鹅珍珠贝酶解产物具有一定的醒酒作用并具备进一步研究开发的价值。     

双酶水解蛋清蛋白最优工艺的研究

为优化蛋清蛋白质的酶水解条件,实验采用Alcalase~2.4LFG和Flavourzyme~500MG复合酶对蛋清蛋白进行水解,并获得了Alcalase~2.4LFG酶水解的最佳工艺条件是底物浓度(S)4.5%、pH值9.5、加酶量(E/S)5%、温度70℃、水解时间为4h。Flavourzyme~500MG酶水解的最佳工艺条件为pH值7、加酶量2%、温度50℃、时间为3h。     

珍珠贝水解肽的制备、氨基酸组成及抗炎活性

目的:高值化利用马氏珠母贝肉生物活性成分及马氏珠母贝肉抗炎活性肽。方法:以马氏珠母贝肉为原料,以水解度(DH)为指标,通过单因素试验和响应面试验优化珍珠贝水解肽工艺制备,并对珍珠贝水解肽的氨基酸组成和抗炎活性进行评价分析。结果:中性蛋白酶为最适酶,酶解最优工艺条件为料液比1∶1 (g/mL),酶解温度46.3℃,酶解时间1.4 h,酶底比0.3%,此时水解度为22.88%,与理论值无显著差异,回归模型可靠。酶解物中必需氨基酸含量达19.84%,疏水性氨基酸含量占比21.19%,带正电荷氨基酸含量为10.46%。在LPS诱导的小鼠巨噬细胞RAW264.7抗炎模型中,珍珠贝水解肽在0～4.0 mg/mL的质量浓度范围内无细胞毒性且有利于巨噬细胞增殖。质量浓度为2.0 mg/mL时,珍珠贝水解肽可有效抑制NO的产生,以及细胞炎症因子TNF-α、IL-6和IL-1β的生成,NO抑制率达到70.00%,TNF-α、IL-6和IL-1β抑制率分别达到83.01%,85.04%,83.11%。结论:珍珠贝水解肽的氨基酸种类齐全,其能有效抑制RAW264.7巨噬细胞NO及细胞炎症因子TNF-α、IL-...     

胰蛋白酶水解玉米胚芽蛋白的研究

研究了胰蛋白酶对玉米胚芽蛋白的水解作用,分析了酶浓度、pH、反应温度、底物浓度等因素对水解度的影响。结果表明:最佳水解条件为酶与底物比2%、温度40℃、pH8.0、底物浓度8%。在此条件下水解4 h,水解度可达10.4%。高效凝胶过滤色谱(HPSEC)分析酶解产物分子量分布发现,酶解产物的分子量主要集中在200~4 000 Da。     

枯草芽孢杆菌蛋白酶水解大豆蛋白的研究

本研究选用枯草芽孢杆菌蛋白酶对大豆蛋白进行水解,分别研究了酶浓度、温度、pH和底物浓度等对酶解效果的影响,得出高水解度低聚肽酶解的最佳工艺条件为:酶浓度8000u/g、温度55℃、pH7.0、底物浓度2%、水解时间4h。     

酶解冷榨菜籽蛋白制备肉味香精的工艺研究

文章以部分脱皮冷榨菜籽粕为原料,通过正交试验确定最佳酶解条件为:先用胰蛋白酶水解,温度45 ℃,pH 8.0,水解时间3 h,酶用量3%,固液比1∶15;再添加中性蛋白酶,温度50 ℃,pH 7.0,水解时间3 h,酶用量3%,固液比1∶15,此时菜籽粕水解度可达到19%.然后通过美拉德反应制备肉味香精,得到最佳制备条件为:温度120 ℃,pH 6.0,木糖浓度6.0%,L-半胱氨酸盐酸盐浓度1.2%,L-甲硫氨酸浓度0.8%,盐酸硫胺浓度0.1%,反应时间60 min.     

紫苏高F值低聚肽的制备研究

以紫苏粕为原料通过酶法水解制备紫苏高F值低聚肽,探讨Alcalase蛋白酶对紫苏粕中蛋白质水解的进程曲线。结果显示其最适条件为底物质量浓度5%(g/100ml)、pH8.5、温度60℃、酶添加浓度5ml/100g底物、时间240min,此水解液进一步用木瓜蛋白酶水解,水解条件为pH7.0、温度55℃、加酶量1%、时间4h,然后用活性炭吸附去除低聚肽中的芳香族氨基酸,吸附条件为pH4.0、温度40℃、活性炭用量7%(m/V)、时间3h,最后得到F值可达79.25的紫苏低聚肽。     

固定化胰蛋白酶水解乌鸡肉制备功能肽的研究

以海藻酸钠为载体,戊二醛为交联剂固定化胰蛋白酶,考察胰蛋白酶的固定化工艺,固定化酶水解乌鸡肉的工艺条件及固定化酶的稳定性。结果表明：固定化胰蛋白酶的最佳条件为：海藻酸钠浓度4%、加酶量10%、pH7.5、温度70℃,酶活力回收率为38.84%;水解乌鸡肉的最佳条件为：固液比1:3(m/V)、pH7.5、加酶量10%、温度60℃,氨基氮含量最高为2.18mg/ml,固定化酶重复使用8 次,酶活力仍保持50% 以上。     

双酶复合水解对玉米肽醒酒活性的影响

采用碱性蛋白酶与风味蛋白酶复合水解玉米蛋白粉制备玉米醒酒肽。研究水解温度,水解时间,酶底比与pH 4个因素对玉米蛋白在水解过程中羟基自由基(·OH)抑制率的影响,通过响应曲面分析方法优化其水解工艺,结果表明:最佳酶解条件为温度55℃、底物质量浓度5g/100mL、pH8.5,按3%的酶与底物比加碱性蛋白酶水解2h后,调整pH至6.95,温度为49.3℃,之后再按4.11%的酶与底物比加风味蛋白酶水解1.6h,·OH抑制率为55.45%。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.