超高压结合酶解法提取鱼油工艺优化

【目的】优化黄鳍金枪鱼(Thunnusalbacares)副产品(鱼头)提取鱼油的工艺参数。【方法】以鱼油提取率为评价指标,采用单因素实验确定最佳超高压处理压强和保压时间,采用Box-Behnken响应面试验设计优化关键酶解工艺参数。【结果】建立鱼油提取率与加酶量、液料质量比、酶解温度和酶解时间之间的回归模型,加酶量、液料质量比、酶解温度和酶解时间对鱼油提取率均有显著影响(P <0.05),影响由高到低依次为加酶量、液料质量比、酶解时间、酶解温度;当超高压处理压强200 MPa、处理时间10 min、加酶量(质量分数)为1.125%、液料质量比为1∶1、酶解温度65℃和酶解时间60min时,根据质量法计算,鱼油提取率达99.51%,与模型预测值之间差异无统计学意义(P> 0.05)。【结论】采用响应面法建立的回归模型较好地描述超高压结合酶解提取鱼油的工艺过程,优化的工艺参数可有效提高鱼油提取率。     

酶解法提取鱼油的工艺参数优化

利用蛋白酶酶解法从黄鳍金枪鱼(Thunnus albacares)加工的下脚料———鱼头中提取鱼油。以鱼油提取率和感官特征为指标,通过正交优化实验设计,获得了胰蛋白酶提取鱼油的最佳酶解工艺参数:酶解温度45℃,酶添加量1.5%,料液质量比1∶1,酶解时间4 h,酶解pH 8。在该条件下,鱼油的提取率为4.34%,理化指标除过氧化值外均达到SC/T3502-2000的粗鱼油二级标准,多不饱和脂肪酸总含量高达38.47%,其中DHA和EPA的含量分别为23.63%和4.84%。     

酶解法提取鱼油的工艺参数优化

利用蛋白酶酶解法从黄鳍金枪鱼（Thunnus albacares）加工的下脚料——鱼头中提取鱼油。以鱼油提取率和感官特征为指标，通过正交优化实验设计，获得了胰蛋白酶提取鱼油的最佳酶解工艺参数：酶解温度45℃，酶添加量1．5％．料液质量比1：1，酶解时间4h，酶解pH8。在该条件下．鱼油的提取率为4．34％，理化指标除过氧化值外均达到SC／T3502-2000的粗鱼油二级标准。多不饱和脂肪酸总含量高达38．47％,其中DHA和EPA的含量分别为23．63％和4．84％。     

响应面法优化制备牡蛎短肽工艺

【目的】探究前处理方式对酶解效果的影响,优化牡蛎短肽制备工艺。【方法】在确定高效酶种类和前处理方式的基础上,以氮回收率、短肽得率为指标对酶解时间、料液比、酶解温度、加酶量进行单因素试验,再利用响应面设计建立数学模型,以短肽得率为响应值,进行4因素3水平的响应面分析。【结果与结论】牡蛎经80℃热处理10 min后使用动物蛋白酶的酶解效果最佳。响应面结果显示,最佳酶解工艺为料液比(g/m L)1∶3.9、温度47℃、加酶量3 300 U/g、自然pH(6.5)、酶解3 h,其短肽得率为(58.53±1.20)%,比原酶解工艺提高24.8%。     

响应面法优化南极磷虾酶法制备DPP-IV抑制肽工艺条件的研究

采用动物蛋白水解酶酶解制备南极磷虾二肽基肽酶-IV(DPP-IV)抑制肽,以DPP-IV抑制率和可溶性蛋白含量为主要指标,考察温度、反应时间、pH、酶添加量对南极磷虾的酶解效果。在单因素的基础上,依据中心组合实验设计原理,运用4因素3水平的响应面分析法,建立动物蛋白水解酶酶解南极磷虾制备DPP-IV抑制肽的二次多项式数学模型,并以DPP-IV抑制率为响应值作响应面。结果表明:南极磷虾酶法制备DPP-IV抑制肽的最佳工艺参数为酶解时间3.85 h、温度45.02℃、pH值7.58、酶添加量237.55 U/g原料;在此条件下,酶解液DPP-IV抑制率的预测值为64.82%,验证值为64.78%,优化方法可行。     

牡蛎酶解工艺优化及其酶解产物对小鼠睾酮分泌的影响

【目的】优化太平洋牡蛎(Crassostreagigas)酶解工艺条件,并研究酶解产物及其超滤组分对体外培养的睾丸间质细胞增殖及睾酮分泌的影响。【方法】以多肽得率为参考标准,对木瓜蛋白酶酶解牡蛎的加酶量、初始pH、酶解时间、酶解温度进行单因素及正交实验优化;通过MTT法及酶联免疫吸附试验(ELISA)检测不同浓度牡蛎酶解产物及其超滤组分对TM3小鼠睾丸间质细胞增殖及睾酮分泌的影响。【结果】木瓜蛋白酶最佳酶解条件为加酶量3 000 U/g,初始pH 6. 5,酶解温度62.5℃,酶解时间4.5 h,在此条件下其多肽质量浓度为14.95 mg/mL;牡蛎酶解液及其超滤组分在0.25～1.00 mg/mL质量浓度范围内,与空白对照组相比,能够显著增加TM3细胞的增殖活性(P0.05),且具有浓度依赖性和时间依赖性。其中,5 ku和5～10 ku超滤组分细胞增殖活性及促进睾酮分泌活性均最强。【结论】牡蛎酶解产物及其超滤组分可有效增强小鼠睾丸间质细胞增殖活性并促进其分泌睾酮。     

海参性腺酶解物制备及其体外清除自由基活性测定

【目的】酶解海参性腺并分析其体外清除自由基活性。【方法】采用外源性蛋白酶水解工艺制备海参性腺酶解产物,通过酶解效果比较分析,考察其体外清除DPPH自由基和羟自由基能力。【结果】确定木瓜蛋白酶为水解用酶,利用响应面优化实验确定酶解条件为酶解时间14 h、酶添加量3 000 U/g、料液比1∶40;酶解液灭酶后经离心、浓缩、干燥后得到粉状海参性腺酶解物,其主要成分质量分数分别为蛋白肽48.4%、矿物质16.8%、粗脂肪12.4%、水分9.8%;酶解产物清除DPPH自由基和羟自由基的IC50值分别为3.39、5.83 mg/mL。【结论】海参性腺酶解物具有良好的抗氧化活性。     

木瓜蛋白酶在制取青鳞鱼可溶性蛋白中的应用

研究了木瓜蛋白酶的酶解温度、酶浓度、酶解时间、加水量、pH值对青鳞鱼可溶性蛋白得率的影响 ,探讨了α 氨态氮含量与青鳞鱼可溶性蛋白得率的关系。结果表明 :温度小于 5 0℃ ,随着酶解温度的提高、酶浓度的增加、酶解时间的延长青鳞鱼可溶性蛋白得率及α 氨态氮的含量均增加 ,α 氨态氮含量增加比可溶性蛋白得率的增加明显 ;加水量的增加 ,可溶性蛋白得率增加 ;pH值对水解效果及可溶性蛋白得率影响不大。综合考虑 ,最佳水解条件为 :温度 5 0℃ ,酶浓度为 1 5 0 0u/g ,酶解时间 80min ,m原料 :m水 =1∶2 ,pH 6 8。酶解所得可溶性蛋白经氨基酸分析仪检测 ,其氨基酸总量为 49 47mg/mL ,必需氨基酸占氨基酸总量的 41 0 % ,游离氨基酸含量为 6 3mg/mL ,肽含量为 87 2 %。     

南海北部湾秋季蓝圆鲹与竹筴鱼的摄食生态及食物竞争

【目的】研究南海北部湾海域秋季蓝圆鲹与竹筴鱼的摄食生态特征和种间食物竞争。【方法】采用胃含物分析法,对2017年10月北部湾底拖网调查和港口随机取样收集的119尾蓝圆鲹(Decapterusmaruadsi)和198尾竹筴鱼(Trachurus japonicus)胃含物样品进行分析,通过肉眼直接观察或显微镜间接观察胃中残留的饵料,饵料种类鉴定、计数、称重等对食性做定量分析,以估算两种鱼类的营养级和生态位宽度,并利用生态位重叠研究两种鱼类的食物竞争关系。【结果与结论】蓝圆鲹的饵料种类19种(属),以桡足类和小型鱼类为主,优势饵料生物为布氏半棱鳀(Encrasicholinapunctifer);竹筴鱼的饵料种类18种(属),以小型鱼类和浮游甲壳类为主,优势饵料为中国毛虾(Acetes chinensis)。两种鱼类均为游泳动物食性,均存在摄食转换,随着叉长的增长,蓝圆鲹的饵料生物由小型浮游动物为主转变为小型鱼类为主,竹筴鱼的饵料生物由小型鱼类为主转变为以樱虾类和较大鱼类为主。蓝圆鲹和竹筴鱼的空胃率、竹筴鱼的平均胃饱满指数均随个体生长呈显著变化(P0.05),但蓝圆鲹的平均胃饱满指数随个体生长无显著变化(P0.05)。蓝圆鲹和竹筴鱼的营养级分别为3.63和3.40,营养生态位宽度分别为1.70和1.24,生态位重叠系数0.56,表明两种鱼类之间存在一定的食物竞争。     

鲢鱼降血压肽的酶解条件

以鲢鱼蛋白为原料,采用5种不同复合蛋白酶(P1,P2,P3,P4,P5)进行酶解,综合研究了复合生物酶酶量、酶解时间、pH、酶解温度等对鲢鱼蛋白酶解降血压肽ACE活性抑制效果的影响。结果表明,复合酶P1酶解降血压肽对ACE抑制率经体外检测为88.08%,具有最佳的酶解效果。对应最佳条件为:酶量25 IU/mL,酶解时间2 h,pH7.0,酶解温度60℃。     

平菇多糖的提取工艺

对平菇多糖提取进行优化研究 ,结果表明 ,平菇多糖提取最佳工艺条件为 :90℃浸提 8h ,m(原料 )∶m(水 ) =1∶30 ,醇析时乙醇体积分数为 80 % ,去除蛋白质时V(粗提液 )∶V(氯仿 +正丁醇 ) =1∶1,V(氯仿 )∶V(正丁醇 ) =10∶3,萃取 30min效果最佳 ,其得率为 1.5 4%。     

Enzymatic hydrolysis of defatted mackerel protein with low bitter taste

Ultrasound-assisted solvent extraction was confirmed as a novel,effective method for separating lipid from mackerel pro-tein,resulting in a degreasing rate (DR) of 95% and a nitrogen recovery (NR) of 88.6%.To obtain protein hydrolysates with high ni-trogen recovery and low bitter taste,enzymatic hydrolysis was performed using eight commercially available proteases.It turned out that the optimum enzyme was the ‘Mixed enzymes for animal proteolysis’.An enzyme dosage of 4%,a temperature of 50℃,and a hydrolysis time of 300 min were found to be the optimum conditions to obtain high NR (84.28%) and degree of hydrolysis (DH,16.18%) by orthogonal experiments.Glutamic acid was the most abundant amino acid of MDP (defatted mackerel protein) and MDPH (defatted mackerel protein hydrolysates).Compared with the FAO/WHO reference protein,the essential amino acid chemical scores (CS) were greater than 1.0 (1.0 1.7) in MDPH,which is reflective of high nutritional value.This,coupled with the light color and slight fishy odor,indicates that MDPH would potentially have a wide range of applications such as nutritional additives,functional ingredients,and so on.     

总状蕨藻多糖提取工艺的研究

采用酶法提取与热水抽提相结合的方法研究了总状蕨藻多糖的提取工艺,结果显示,采用固液质量比1∶10,蛋白酶用量136.5 U/g,于60℃下酶法提取2.5 h后,再将固液质量比调至1∶20,在温度95℃条件下继续进行热水提取2.5 h,多糖得率为6.7%,比单用热水提取法提高了131.0%。     

基于SWAT模型和多源DEM数据的流域水系提取精度分析

流域水系是研究水文水资源、地貌演化和生态环境及水土治理等的基础数据,高精度的水系提取对流域研究十分重要。本文以空间分辨率均为30 m的 AW3D30 DSM、SRTM1 DEM和ASTER GDEM2数字高程模型作为基本的地形数据,基于SWAT模型提取犟河流域水系,通过河网“套合差”、水系相对误差、Google Map水文数据及蓝线河网对提取结果进行误差分析与综合评价,探讨河道剖面和地形特征对水系提取精度的影响。结果表明：① 集水面积阈值是决定河网水系提取精度的关键参数,阈值越大,提取的河网密度越小,反之提取的河网密度越大;② 基于河网密度与集水阈值二阶导数的幂函数与直线相切的数学求值方法确定流域最佳集水面积阈值,能避免最佳集水阈值取值的主观性,提取的河网水系与实际河道相符;③ AW3D30 DSM数据提取的流域河网水系与Google Map高分辨率影像的水系偏差最小,且AW3D30 DSM数据提取的水系与蓝线河网的河网“套合差”和水系相对误差值均最低,能真实反映中低山丘陵山区流域水系发育的疏密程度,吻合度最好;④ 多源DEM数据提取结果均显示为河床比降大和横剖面曲线为窄深式的“V”形河谷提取的水系精度高于河床比降小和横剖面曲线为 “碟”形河谷的提取精度;⑤ AW3D30 DSM数据的地形起伏和坡度标准差最大,有利于山区河网水系的提取。因此,基于SWAT模型和AW3D30 DSM数据提取的山区流域水系可最大限度反映流域水系的真实情况,精度最高,此方法和数据源可应用于中低山丘陵山区流域的水系提取研究。     

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.     

Optimal content and ratio of lysine to arginine in the diet of Pacific white shrimp, Litopenaeus vannamei

The optimal quantity of dietary lysine (Lys) and arginine (Arg), and the optimal ratio of dietary Lys to Arg for Pacific white shrimp Litopenaeus vannamei were investigated. Coated Lys and Arg were added to a basal diet (37.99% crude protein and 7.28% crude lipid) to provide graded levels of Lys and Arg. The experimental diets contained three Lys levels (2.51%, 2.11%, and 1.70% of total diet), and three Arg levels (1.41%, 1.80%, and 2.21% of total diet) and all combinations of these levels were tested. Pacific white shrimp, with a mean weight of 3.62±0.1 g, were randomly distributed in 36 fiberglass tanks with 30 shrimp per tank and reared on the experimental diets for 50 days. After the feeding trial, the growth performance, survival, feed conversion rate (FCR), body composition and protease and lipase activities in the hepatopancreases of the experimental shrimps were determined. The results show that weight gain (WG), specific growth rate (SGR), FCR, body protein, body Lys and Arg content were significantly affected by dietary Lys and Arg (P <0.05) and improved when dietary Lys and Arg levels were 2.11% ～ 2.51% and 1.80%～2.21%, respectively. Protease and lipase activities in the hepatopancreases of the shrimps appeared higher when dietary Lys and Arg quantities were 2.11% ～2.51% and 1.80%～2.21%, although the difference was not statistically significant (P >0.05). Therefore, according to our results, the optimal Lys and Arg quantities in the diet of Pacific white shrimp, L. vannamei, were considered to be 2.11%–2.51% and 1.80%–2.21%, respectively, and the optimal ratio to be 1:0.88–1:1.05.     

罗非鱼下脚料自溶条件的初步探讨

采用单因素和正交优化实验L9(43)确定酶法自溶罗非鱼下脚料的最适条件,结果表明,最适自溶条件为:料液质量比1∶3,反应温度50℃,pH7.5,反应时间6.5h;酶解结束蛋白质回收率为81.75%。     

Study on Application of Polyenzyme Method to Offal of Harengula zunasi

The new polyenzyme method for making gravy from Harengula zunasi offal involves protein enzymolysis with flavorase after proper alkaline and neutral protease levels were established by orthogonal trials to select the best hydrolytic conditions for processing offal with alkaline and neutral protease. The conditions for the polyenzyme method were pH of 7.0, temperature of 50℃ , alkaline and neutral protease concentration of 1.5% respectively, hydrolysis time of 120 min, andflavorase concentration of 2.0% , for 60 min. The new gravy-making technology yields a nutritious and delicious gravy containing 40.3 % of total essential amino acids, with delicious amino acids Glu, Asp, Gly, Ala, Pro and Ser comprising 49.5% , total and amino nitrogen being respectively1.9 and 1.1 g/100 g (amino acid nitrogen being 61.0% of total nitrogen), The polyenzyme method was used to make 14.8% protein gravy from Harengula zunasi offal. In addition, in inorganic elements, the phosphorus content is the highest.     

超声波辅助提取河豚毒素的研究

以月腹刺鲀(Gastrophysus lunaris)卵巢为原料,利用超声波辅助提取河豚毒素(Tetrodotoxin,TTX)。通过单因素实验及二次回归旋转组合设计实验研究液料比、超声温度、超声时间等因素对提取率的影响,确定超声波辅助提取河豚毒素的最佳工艺条件。结果表明:在实验范围内影响河豚毒素得率的各因素大小依次为液料体积质量比、超声温度、超声时间;超声波辅助提取河豚毒素的最佳工艺条件为液料体积(mL)质量(g)比3.03∶1,超声温度39℃,超声时间22 min,该工艺条件下提取河豚毒素得率为63.57μg/g。