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1.
在蛋白酶水解法制备香菇酱的工艺中,首先研究了超声波对原料进行细胞破碎处理的操作条件,采用正交实验设计对影响蛋白酶水解效果的条件进行了选择优化。结果表明,超声波处理的最佳功率为200W、最佳处理时间为30min,蛋白酶水解的最佳工艺条件为酶解温度40℃、pH值4.5、酶用量1%、酶解时间60min,在此工艺条件下香菇酱的氨基酸含量为0.88%。  相似文献   

2.
鱼鳞中含有丰富的蛋白质资源,如何充分利用该资源越来越受到关注.利用碱性蛋白酶水解海洋鱼鳞蛋白制备鱼鳞蛋白多肽.通过考察温度、时间、酶量、底物浓度等单一因素对水解鱼鳞蛋白的影响,确定并设计了L9(34)正交试验因素和水平,最终获得了碱性蛋白酶水解海洋鱼鳞蛋白优化工艺条件,即温度60℃,时间1.5h,酶量3%(质量分数),底物质量分数10%.在此条件下,酶解所得水解度为32.38%.与其他方法比较,该工艺条件下水解时间大大缩短.检测了该条件所得蛋白肽段的分子质量分布,结果表明酶解产物主要集中在1~6ku.由此可见,该优化条件适合规模化生产,所得蛋白肽可以满足食品、化妆品行业的需求.  相似文献   

3.
以条斑紫菜为原料,研究紫菜的酶解及其风味香精制备技术.通过比较不同蛋白酶对条斑紫菜的水解能力及对水解后风味的影响,进而筛选水解用蛋白酶.利用筛选的风味蛋白酶酶解紫菜,以水解度和感官评价为评价指标,通过正交试验确定风味蛋白酶水解紫菜的较佳工艺条件为:温度55℃,时间3h,加酶量3%.以此酶解液进行美拉德反应制备紫菜风味香精,通过响应面分析法确定美拉德反应的工艺配方与工艺条件为:谷氨酸1 mg/mL,甘氨酸0.5 mg/mL,半胱氨酸0.15 mg/mL,木糖8 mg/mL,葡萄糖4 mg/mL,硫胺素0.4 mg/mL,温度110℃,pH6,时间50 min,制备的紫菜风味香精香味浓郁、鲜味明显,腥味减弱.氨基酸分析结果表明,酶水解后谷氨酸和丙氨酸含量增加明显,参与美拉德反应的氨基酸主要有甘氨酸、谷氨酸、半胱氨酸等.采用GC-MS测定产物中的挥发性风味成分,共检测出41种风味物质.  相似文献   

4.
Alcalase酶解鸡肉蛋白及产物的自由基清除活性   总被引:4,自引:0,他引:4  
采用高效液相色谱研究了Alcalase酶解鸡肉蛋白过程中氨基酸、肽的释放规律,并通过邻二氮菲-Fe^2+氧化法、邻苯三酚自氧化法分析产物的羟自由基、超氧自由基清除活性.结果表明:可溶性蛋白质、游离氨基酸含量在酶解过程中逐渐增加;酶解产物中肽的总量在前16h不断增加,随后下降;不溶性蛋白的溶出以厦相对分子质量大于10000的肽段的降解在酶解初始4h内基本结束;相对分子质量在5000一10000间的肽占总肽的量值在酶解初始4h内显著增加,4—8h内明显下降,随后变化不大(P〉0.1);相对分子质量在3000—5000间的肽占总肽的量值在整个酶解过程中变化不明显(P〉0。1);而相对分子质量小于3000的肽在水解初始8h内占总肽的量值显著增加,随后也无明显变化(P〉0.1).鸡肉未酶解样、不同酶解时间产物均具有显著的羟自由基、超氧自由基清除活性,但前者活性更强,这与鸡肉酶解产物中肽和氨基酸的组成有关,  相似文献   

5.
希望借助超声波预处理,提高玉米黄粉酶解制备ACEI活性肽的反应效率.通过单因素试验和响应面分析法优化得到玉米黄粉脉冲超声预处理的最优工艺:超声频率20 kHz,超声功率1 000 W,超声时间13.18 min,料液温度51.59 ℃,脉冲超声工作间歇时间比2 s/2 s.在上述条件下酶解产物对ACE抑制率达66.24%.与未超声的对照组相比,在保持酶解产物IC50值基本不变的情况下,超声预处理原料后酶解产物的抑制活性提高了74.08%,生产效率提高了55.11%,蛋白转化率提高了55.06%,米氏常数km降低了33.30%.  相似文献   

6.
实验研究主要是以碎米糖化制糖以后剩下的下脚料米渣为生产原料,依照米渣的蛋白高温变性优势,充分利用超声波技术对米渣蛋白进行改性,通过超声作用来使紧致的蛋白质分子出现松散,进而利用多酶复合水解米渣蛋白的方式,控制水解条件,获得最优水解度。针对水解后的产物展开膜法分离,再依据活性肽的分子分布水平来截取出米渣蛋白的水解产物,然后对水解产品的理化特性和营养学价值进行评估,来设计出合适的产品配方,提高大米蛋白活性肽的市场应用价值。  相似文献   

7.
江苏大学开发的“紫菜降血压肽制备技术研究”日前通过省科技厅组织的鉴定.该成果建立了超声渡与酶水解耦合技术制备条斑紫菜降血压肽的方法,进行了条斑紫菜降血压肽的纯化与结构鉴定,从条斑紫菜酶解液中获得了Cys—Ser—Asn—Arg和Pro—Cys—His—Trp两条新的高活性降血压肽。其抑制ACE活性的IC50值分别为24.71和5.38μg/ml,具有良好的耐高温性和酸稳定性.条斑紫菜降血压肽对原发性高血压大鼠具有降血压作用,呈量效关系.该研究成果将与南通、连云港等我省重要的紫菜产地企业、我省乃至全国的功能食品、医药等高新技术企业密切联系、合作。加速产业化进程.  相似文献   

8.
探讨了超声波辅助前处理对花生分离蛋白复合酶解的影响,比较了碱性蛋白酶、木瓜蛋白酶、胰蛋白酶、胃蛋白酶、中性蛋白酶、风味蛋白酶等六种蛋白酶解物清除DPPH自由基的效果,确定碱性蛋白酶和胰蛋白酶较佳的复合比例为8∶2.在此基础上,开展响应面优化试验,以DPPH自由基清除率和水解度为指标,探讨复合酶与风味蛋白酶酶解的较佳工艺参数,并分析DPPH清除率和水解度相关性.实验结果表明,复合蛋白酶制备花生分离蛋白抗氧化肽的较佳酶解工艺为pH 8.5,温度49.36℃,酶添加量(E/S,质量分数m/m)3.40%,酶解时间203.59 min.  相似文献   

9.
米糠蛋白活性肽的制备工艺研究   总被引:1,自引:0,他引:1  
初步研究酶法水解米糠蛋白制备米糠活性肽的工艺条件,同时探讨了不同料液比、pH值、温度和提取时间对蛋白水解率的影响.通过正交优化实验得出酶水解米糠蛋白的最佳条件是:酶解温度37℃,加酶量为0.5%,酶解时间是3h,酶解pH值为9.结果表明碱性蛋白酶酶解法和三氯乙酸酸溶法相结合,是一种很理想又有效的制备蛋白肽的方法.  相似文献   

10.
以搅碎的兔肉末为原料,以超声辅助酶解制备抗氧化肽,对其抗氧化活性进行评价,发现抗氧化活性较好.比较不同酶制备的抗氧化肽的DPPH自由基清除率,从胰蛋白酶、碱性蛋白酶、中性蛋白酶、菠萝蛋白酶和木瓜蛋白酶中筛选出最佳用酶,利用单因素实验和响应面法优化了兔肉酶解的工艺条件.结果表明,酶解效果最好的是胰蛋白酶,在超声时间22.5 min,超声温度37℃,超声功率330 W的条件下酶解得到的抗氧化肽DPPH自由基清除率最好,为81.17%,与响应面优化实验回归模型的预测值基本一致;在此基础上制备兔肉抗氧化肽,对酶解液的ABTS、羟基自由基和超氧阴离子清除率进行检测,值分别为44.03%、94.69%和34.32%,均大于未酶解液.该研究可以为制备兔肉抗氧化肽方面提供理论依据和数据支持.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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