紫苏饼粕浓缩蛋白溶解性与乳化特性的研究

以氮溶解指数、乳化活性和乳化稳定性为考察指标,研究了温度、pH值、离子强度、蛋白质质量浓度、蔗糖添加量等对紫苏饼粕浓缩蛋白溶解特性和乳化特性的影响。紫苏饼粕浓缩蛋白的NSI在50～60℃范围内最大。紫苏饼粕浓缩蛋白的等电点在pH4.4,其溶解度与pH值的关系呈典型的V型。低浓度(<0.05 mol/L)的NaCl对蛋白质的溶解性和乳化性均表现为正面作用,而高浓度(0.1～0.25 mol/L)NaCl对其影响则截然相反。添加蔗糖(0%～2.5%)明显改善了紫苏饼粕浓缩蛋白的乳化活性与乳化稳定性。     

紫苏饼粕蛋白酶法提取工艺研究

以紫苏饼粕为原料,对紫苏蛋白质的纤维素酶法提取工艺进行了研究。选取提取液pH、反应时间、反应温度及纤维素酶添加量4个单因素进行试验。在单因素试验基础上,采用L9(34)正交设计方案,对紫苏蛋白质纤维素酶法提取工艺进行优化。结果表明,最佳提取工艺条件为:pH 5.0,反应时间50 min,反应温度55℃,纤维素酶质量分数2.0%。在最佳工艺条件下,紫苏饼粕蛋白提取率达到38.2%,纯度达到84.5%,得率最高可达86.5%。     

响应面优化紫苏饼粕蛋白提取工艺

以脱脂紫苏饼粕为原料,采取碱溶酸沉法提取紫苏饼粕蛋白.在单因素试验基础上,选取碱提pH、碱提温度、碱提时间3个考察因素,以紫苏饼粕蛋白提取率作为评价指标,采用响应面优化结合Box-Behnken设计试验获得最佳提取工艺条件.结果 表明,紫苏饼粕蛋白提取的最佳工艺参数为:饼粕颗粒大小＜0.25 mm,料液比1∶25(g/...     

美拉德反应修饰紫苏蛋白及其抗氧化活性研究

以紫苏饼粕为原料,采用碱溶酸沉法提取蛋白,以糖为修饰剂,以DPPH自由基清除率为考察指标,通过单因素实验、响应面分析法优化制备紫苏蛋白美拉德反应修饰产物工艺,研究其抗氧化活性。结果表明,在料液比1∶12、碱溶pH 9.0、 50℃、溶解40 min、酸沉pH 4.4条件下,提取的紫苏蛋白纯度达69.9%。单因素实验制备糖-紫苏蛋白美拉德反应产物的最适工艺为最适糖种类为木糖、紫苏蛋白于100℃加热4 h,紫苏蛋白与木糖最适质量比15∶1,初始pH 9.0。响应面优化结果显示各因素对抗氧化能力影响的主次顺序为起始pH值>紫苏蛋白与木糖的质量比>反应时间;结合实际,其最佳工艺为初始pH 8.2、反应时间4.85 h、紫苏蛋白与木糖的质量比15∶1,此时对DPPH自由基的清除率达55.3%,与预测值54.18%接近,紫苏蛋白美拉德反应产物有较好的抗氧化活性。     

混菌固态发酵紫苏饼粕工艺优化与紫苏饼粕蛋白特性研究

以发酵紫苏饼粕蛋白含量为指标,采用单因素和正交试验优化混菌固态发酵紫苏饼粕,并研究发酵对紫苏饼粕蛋白质功能性质、组成及微观结构的影响。结果表明:混菌固态发酵的最优工艺为马克斯克鲁维酵母与纳豆芽孢杆菌体积比1.5︰1,料液比1︰2(g/m L),发酵温度33℃,在此条件下混菌发酵后紫苏饼粕蛋白含量达到38.93%,混菌比例对发酵后紫苏饼粕蛋白含量的影响显著(P0.05),此条件下紫苏饼粕蛋白的持水性,溶解性均优于未发酵的紫苏饼粕蛋白。发酵后紫苏饼粕中相对分子量小的蛋白比例增多;发酵后提取的紫苏饼粕蛋白微观结构无可见的孔洞,呈现熔融状态。     

水酶法提取紫苏籽油脂和蛋白质的工艺条件

利用响应面法对水酶法提取紫苏籽油和蛋白的工艺进行优化。在单因素试验基础上,以pH值、温度、酶添加量、时间为影响参数,油和蛋白得率为响应值,应用Box-Behnken试验建立数学模型,进行响应面分析。结果显示,拟合得到的方程显著,可以用以预测不同条件下油与蛋白质提取率,水酶法提取紫苏籽油及回收蛋白质的最优工艺条件为料液比1:4(g/mL)、pH8.94、温度61.3℃、酶添加量(质量分数)为1.5%、时间4.47h,在此条件下,油脂及蛋白质提取率分别为85.59%、73.43%。     

鸡腿菇子实体蛋白提取工艺优化及其特性研究

以鸡腿菇子实体为原料,研究其蛋白的提取工艺及特性。以提取液pH值、提取温度、料液比、提取时间为提取鸡腿菇子实体蛋白的影响因素,采用正交试验优化碱溶酸沉法提取蛋白的工艺条件,结果表明:鸡腿菇子实体蛋白的最佳提取工艺参数为提取液pH11.5,提取温度50℃,料液比1:15,提取时间50min,此时蛋白提取率为24.3%。在pH3.5条件下沉淀蛋白效果最佳。对制备的鸡腿菇子实体蛋白特性的分析表明:其分子质量主要集中在50～90ku,20～35ku和13～17ku等区间内;必需氨基酸(EAA)占氨基酸总量(TAA)的40.57%,必需氨基酸与非必需氨基酸(NEAA)的比值为0.68,为理想蛋白质,且其所含人体必需氨基酸种类齐全,比例均衡,比值系数分(SRC)为80.69;在碱性条件下,鸡腿菇子实体蛋白具有良好的溶解性、乳化性和起泡能力。     

发酵紫苏粕制备抗氧化肽的工艺优化及抗氧化性

以脱脂后的紫苏炼油副产物紫苏粕为原料,选取酵母菌为发酵菌种,通过单因素和响应面试验探究紫苏粕发酵工艺对饼粕中蛋白质含量的影响,得到的优化条件为发酵液pH3.4、液料比5.0∶1（mL/g）、接菌量为8.5%（质量分数）、发酵时间24 h,此条件下蛋白质含量为0.679 mg/g。以最优条件下发酵后的紫苏粕酶解制备抗氧化肽,研究酶种类与酶用量对发酵后紫苏粕抗氧化性的影响。结果表明,发酵后紫苏粕蛋白经碱性蛋白酶水解后,其抗氧化能力强于胰蛋白酶水解后的酶解液,且当碱性蛋白酶的用量在5.0%（800 U/g）时,酶解液对DPPH 自由基、羟基自由基、ABTS+自由基、超氧阴离子自由基清除能力达到最佳。     

山核桃饼粕蛋白的酶辅助碱法提取工艺优化

以冷榨山核桃饼粕为原料，采用酶辅助碱法提取山核桃蛋白。以提取率为指标，在单因素试验的基础上通过正交试验优化提取工艺，并分析其分子质量。结果表明：最优工艺为pH 10.0、碱性蛋白酶添加量1 000 U/g、料液比1∶16(g/mL)、提取时间1.5 h、提取温度60℃,在此条件下得蛋白质提取率为84.8%;采用连续控制提取液pH恒定法，提取率可提高至89.7%。山核桃饼粕蛋白亚基分子质量为10～70 kDa。     

紫苏饼粕的残油醇提工艺及品质分析

为提取紫苏饼粕残油,减少有毒有机溶剂残留和污染,同时获得低脂、高蛋白紫苏饼粕,采用95%乙醇浸提法提取紫苏饼粕残油。在单因素试验的基础上,选出最优浸提温度、浸提次数、液固比、浸提时间。通过正交试验优化获得的工艺条件为:浸提温度75℃、浸提次数5次、液固比3.50:1、时间3 h。在该工艺下对紫苏饼粕残油的提取率可达96.04%,紫苏饼粕含油率降至0.51%,蛋白富集率提升至57.90%。对紫苏籽压榨油、紫苏饼粕乙醇浸提油及石油醚浸提油进行理化性质比较,结果表明三种油在酸值、过氧化值、碘值、皂化值方面均符合国家标准,其中石油醚浸提油的酸值和过氧化值较大分别为3.65 KOH/(mg/g)和5.96 mmol/kg,乙醇浸提油次之,低温压榨油较小为3.30 KOH/(mg/g)和5.22 mmol/kg。碘值无显著差异,而浸提油的皂化值要大于低温压榨油。通过气相色谱(GC)分析,乙醇浸提油的亚麻酸相对含量及不饱和脂肪酸占总脂肪酸比例分别为59.60%和89.31%,略低于低温压榨油的61.09%和90.33%,高于石油醚浸提油的57.29%和86.10%。综合来看乙醇浸提油品质高于石油醚浸提油,略低于低温压榨油。     

紫苏籽中不同蛋白组分的功能性质研究

以紫苏籽为原料,经粉碎过60目筛后石油醚脱脂得到紫苏籽脱脂粉,然后采用不同方法提取得到紫苏籽分离蛋白、清蛋白和球蛋白,研究了3种蛋白的氨基酸组成及持水性、溶解性、乳化性等功能特性。结果表明:紫苏籽脱脂粉中蛋白质含量丰富,不同紫苏籽蛋白的氨基酸组成相近,其中谷氨酸含量最高,且均含有8种必需氨基酸;分离蛋白的热变性温度稍高于其他两种蛋白;清蛋白的持水性、持油性较好;在pH 1～10范围内,3种蛋白的溶解性均呈现出U型变化趋势,其中球蛋白的溶解性最好;在不同pH下,球蛋白的乳化活性和乳化稳定性高于其他两种蛋白。     

Factors affecting production of a near-white protein isolate from grapeseed

Extraction and precipitation conditions were investigated to determine the optimum conditions for preparation of a near-white protein isolate from grapeseed flour, treated with ammonium hydroxide and defatted. Extraction and precipitation of protein was studied under the following conditions: Particle size (<20 to >80 mesh). flour to solvent ratio (1:5–1:40), pH (1–12), NaCl medium (1–10%), extraction time (15–60 min) and precipitation pH (3–5). Protein solubility was less than 65% above pH 10. Using 60–80 mesh flour and extracting at pH 11 for 30 min with a flour to solvent ratio of 1:15, a protein isolate was obtained by acidification to pH 4.5 containing 84.7% protein and representing 48.2% of the crude protein in the grapeseed. The isolate was relatively low in sulphur-containing amino acids and lysine but rich in other essential and non-essential amino acids and had a digestibility of 91.3%. The isolate showed reasonably good whipping and emulsifying characteristics as well as water and oil absorptions.     

Nitrogen extractability of sesame (Sesamum indicum L.) seed and the preparation of two protein isolates

Nitrogen extractability from sesame flour in water is greatest using a flour: solvent ratio of 1:40 and an extraction time of 15 min. At pH 4.0-6.5, <10% nitrogen is extracted, whilst >90% is extracted at pH 11.0. In the presence of NaCl (0.5-1.0M) nitrogen extractability is greatest at pH values > pH 4.0. The two sesame protein isolates produced were bland-tasting, light-coloured and contained approximately 95% protein. The alkali isolate (extracted in water at pH 10.0 and precipitated at pH 4.0) was readily solubilised and showed a good protein recovery (60%). The salt isolate (extracted in 1M NaCl at pH 6.0 and precipitated at pH 4.0) was less soluble and showed a lower protein recovery (50%). The sesame products were extracted sequentially using various solvents. Sesame flour proteins were mainly salt-soluble (67%), alkali isolate proteins mainly water-soluble (41%) and alkali-soluble (41%), and salt isolate proteins mainly alkali-soluble (35%). The amino acid composition of the sesame products is described. Oil-expelled cake showed poor nitrogen extractability (53% at pH 11.0 in water) and was, therefore, a poor source for protein isolate production.     

液压压榨澳洲坚果粕蛋白质提取工艺优化及其组成分析与功能性质

以液压压榨澳洲坚果粕为原料,采用碱溶酸沉法提取蛋白质,通过单因素与正交试验确定最佳提取条件,并对其组成与功能性质进行研究。结果表明:澳洲坚果粕蛋白质提取工艺各因素对提取率影响的主次顺序依次为料液比、碱溶p H值、提取时间、提取温度,且均达到了极显著水平(P0.01),最佳提取工艺条件为:料液比1∶50(g/m L)、碱溶p H 9、提取时间2 h、提取温度40℃。在此条件下提取率达到95.40%,纯度为65.46%。澳洲坚果粕蛋白质中清蛋白、球蛋白、醇溶蛋白、谷蛋白质量分数依次为:7.29%、14.58%、14.95%、63.18%。澳洲坚果粕蛋白质的等电点约为5.0。在适宜的p H值条件下,澳洲坚果粕蛋白质具有较好的溶解性、乳化性、乳化稳定性与泡沫稳定性,起泡性相对较差。在70℃温度条件下,吸油性达到最大值,为50.10%。     

Evaluation of mustard (Brassica juncea) protein isolate prepared by steam injection heating for reduction of antinutritional factors

A process for the preparation of mustard protein isolate, comprising steps such as dispersion of defatted meal in 0.1 mol/l NaCl solution, incubation, extraction at alkaline pH, followed by treatment of the protein solution with activated carbon was developed. The protein, coagulated by steam injection, was subjected to separation by centrifugation, washing and spray drying. The parameters evaluated were protein yield, purity, presence of antinutritional factors and nutritional quality of proteins. The protein yield was 58-60%. The purity of the protein isolate was 95%. The hydrolysed products of glocosinolates like isothiocyanates and oxazolidine thione levels, phenolics and phytic acid levels were low in the protein isolate. The in vitro digestibility of the protein isolate was 92.4% compared to 80.6% of the meal. Chemical score of the meal and protein isolate were similar; isoleucine was the first limiting amino acid. The calculated nutritional indices, essential amino acid index, biological value, nutritional index and C-PER of protein isolate were higher compared to meal. The protein quality as indicated by amino acid profile and PDCAAS scores for 10-12-years old and adults were 100.     

鳞杯伞可溶性蛋白提取工艺的优化及其营养评价

以五台山鳞杯伞子实体为原料,采用响应面分析法对鳞杯伞蛋白提取工艺进行优化,并对其蛋白氨基酸组成与营养价值进行分析。鳞杯伞可溶性蛋白的提取在单因素的基础上,选取料液比、提取液pH值、提取温度3个关键的因素进行响应面试验,最佳提取条件为:液料比31 mL/g、提取液pH 11、提取温度51℃、提取时间60 min,蛋白提取率达(33.65±0.17)%。在此提取条件下,样品蛋白的氨基酸分析表明:鳞杯伞蛋白氨基酸种类齐全,必需氨基酸(essential amino acid,EAA)占氨基酸总量(total amino acid,TAA)的39.35%,必需氨基酸与非必需氨基酸(nonessential amino acid,NEAA)的比值为64.89%,该样品蛋白接近联合国粮农组织(Food and Agriculture Organization,FAO)/世界卫生组织(World Health Organization,WHO)提出的推荐值;因此,可以作为一种优质的蛋白质。     

Physicochemical and Functional Properties of Winged Bean Flour and Isolate Compared with Soy Isolate

The proximate composition, amino acid profile and functional properties of isolated winged bean proteins were determined and compared with soy protein isolate. Winged bean protein extracted at pH 10 and pH 12 had protein contents of about 90% and 80%, respectively. Alkali extraction of winged bean proteins at pH 10 and pH 12 did not affect the amino acid distribution of the isolated proteins. Oil and water absorption, emulsion, and foaming properties of winged bean isolated compared favorably with soy isolate. Least gelation concentration for winged bean isolate was 18% compared to 14% for soy isolate. Thus, winged bean protein isolate with its high protein content, high lysine and other essential amino acid content and good functionality has a good potential as an ingredient in food products.     

花生分离蛋白提取工艺优化研究

采用碱提酸沉方法从脱脂花生蛋白粉中提取花生分离蛋白,在单因素试验的基础上,应用响应面法优化花生分离蛋白的提取条件。结果表明：浸提时间和碱液pH 值对提取的花生分离蛋白纯度都有显著影响,且呈非线性关系,最佳提取工艺参数为浸提时间131min、浸提温度50℃、碱液pH10、料液比1:12(g/mL)。在此条件下,花生分离蛋白的纯度为95.05%、提取率71%。响应面法对花生分离蛋白提取条件的优化是可行的。     

响应面优化花生分离蛋白提取工艺的研究

采用碱提酸沉法从低变性花生粕中提取花生分离蛋白,以花生分离蛋白提取率为响应值,应用Box-BehnkenDesign(BBD)对碱提温度、时间、pH和液料比4因素进行响应面分析,确定碱提的最佳工艺条件为:碱提温度57.5℃、时间100min、pH9.2和液料比12∶1;通过单因素实验确定最佳酸沉pH为4.5。在此条件下,花生分离蛋白最高提取率为87.57%,与预测值87.88%相对误差约为0.4%。     

Countercurrent extraction-isoelectric precipitation of sunflower seed protein isolates

A countercurrent extraction-isoelectric precipitation procedure for the preparation of protein isolates from defatted sunflower seed meal is described. Using 0.04M NaOH and a solvent:meal ratio of 20:1, as much as 95% of meal nitrogen was extracted. Precipitation at pH 4.0 resulted in an isolate containing 88.4% of the meal protein. Using 0.1% sodium sulphite with the alkaline solution in the countercurrent extraction resulted in a white, bland and highly pure protein isolate. Isolated sunflower seed protein is limiting in the amino acid lysine, while other essential amino acids are present in amounts which meet the dietary requirements of chicks and human adults.