以淮山粉、脱脂奶粉为原料,探究淮山酸奶的发酵工艺.以感官评价为响应值,在单因素实验的基础上,利用Plackett-Burman实验、最陡爬坡实验、响应面优化法进行分析,确定了淮山粉、奶粉、白糖的添加量、发酵时间和发酵温度,并对酸奶成品进行理化及微生物指标检测.结果表明:淮山酸奶发酵的优化工艺条件为淮山粉添加量4.9％、奶粉添加量8.0％、白糖添加量5.9％、发酵时间5.5 h、发酵温度43℃,此条件下的酸奶感官评分为92分,与预测值(93.129分)相差较小.理化及微生物指标检测结果为酸度81 oT,糖度为8.13oBrix,乳酸菌数量为1.09×108 mL-1,未检测出大肠杆菌,蛋白质含量为3.1％,以上结果均符合国家食品标准.

为优化银叶金合欢组培苗生根培养基条件,通过单因素试验确定IBA、NAA、IAA几种激素对银叶金合欢组培苗生根状况的影响,选出IBA、NAA 2种激素的最佳范围,以银叶金合欢组培幼苗根数、生根率为响应值,利用Design-Expert8.0.6软件对中心组合设计所得实验数据进行二次回归拟合,并进行响应曲面法分析.结果表明:银叶金合欢最优生根培养基为1/2MS+IBA0.8 mg/L+NAA0.3 mg/L+蔗糖15 g/L,此条件下银叶金合欢幼苗根数3.756条,生根率71.506％.认为通过响应面法建立的模型预测性良好,可有效优化银叶金合欢组培生根培养基条件.

以葛根粉、全脂奶粉以及白砂糖为原材料,通过单因素试验、Plackett-Burman试验、最陡爬坡试验和响应面优化试验确定葛根酸奶最佳发酵工艺,对葛根酸奶的酸度、糖度、乳酸菌数、大肠杆菌数以及抗氧化性进行检测.结果 表明,葛根酸奶的最佳发酵工艺为白砂糖添加量6％,发酵温度42℃,葛根粉添加量3.8％,全脂奶粉添加量8.2％,发酵时间5h.在此优化工艺条件下,酸奶感官评分为90分,与预测值(89.37分)相近;葛根酸奶的酸度72 °T,糖度为8.6％,乳酸菌数为1.3×108 CFU/mL,大肠杆菌未检出,检测结果均符合各项相对应的食品安全国家标准;葛根酸奶对DPPH和羟自由基的清除率分别为39.8％和35.8％,清除能力均强于原味酸奶(34.8％和31.5％).

本试验以珍珠相思带腋芽的茎段为外植体,采用响应面法优化珍珠相思诱导及增殖培养基,以期提高珍珠相思外植体的诱导率以及不定芽的增殖系数,为珍珠相思建立组培快繁体系提供参考依据.通过单因素试验确定不定芽诱导及增殖的基本培养基以及激素添加范围,并利用响应面法中的CCD设计进行优化分析.结果表明,由单因素试验法分析MS培养基可作为珍珠相思不定芽诱导培养的最佳基本培养基;不定芽诱导与增殖培养基激素添加范围分别为6-BA 1.5～2.5 mg/L,NAA 0.1～0.3 mg/L,2,4-D 0.10～0.20 mg/L、6-BA 0.6～1.0 mg/L,NAA 0.3～0.5 mg/L,GA3 0～0.2 mg/L.再通过响应面法得到最佳诱导培养基、增殖培养基分别是 MS+6-BA 2.00 mg/L+NAA 0.2 mg/L+2,4-D 0.14 mg/L、MS+6-BA 1.00 mg/L+NAA 0.40 mg/L+GA3 0.06mg/L,其实际诱导率、增殖系数分别为89.36％、3.54,与预测值十分接近,说明回归方程与真实试验拟合度较好.本研究创新性应用响应面方法优化珍珠相思不定芽诱导及增殖培养条件,减少了实验次数,节省了试验成本和时间,能广泛应用于工厂化育苗,为珍珠相思的良种选育及推广种植奠定理论和实践基础.

目前,植物组织培养的优化策略较多,其中大多数使用单因素试验法或正交试验法研究各因素之间的交互作用,最终得到最优方案.而响应面法(RSM)是采用数学统计方法进行模型拟合并展开优化分析,从而得到最优研究方案.该文从响应面法在初代培养(诱导培养)、继代培养(增殖培养)、生根培养以及其他培养条件中的应用等方面综述了目前响应面法在植物组织培养中的应用现状,并对今后的运用进行了展望,以期为优化植物组织培养过程和实现规模化生产提供参考.

螺旋藻富含优质蛋白质,为有效利用这一蛋白质资源,试验探究了复合蛋白酶水解螺旋藻制备多肽的工艺路线.通过单一酶解及复合酶解试验考察了不同蛋白酶对螺旋藻水解效果的差异,以及不同蛋白酶对螺旋藻水解作用的协同效果,由此筛选出适合螺旋藻水解的最佳蛋白酶为:由碱性蛋白酶、胰蛋白酶、木瓜蛋白酶按酶活比2∶1∶1的比例构成的复合蛋白酶.采用单因素及响应面试验对复合蛋白酶水解螺旋藻的工艺条件进行了优化,得到螺旋藻酶解的最适工艺条件为:螺旋藻浓度50 g/L,pH9.0,加酶量6 000 U/g蛋白,温度52℃,酶解时间6.2h.在优化的工艺条件下,水解螺旋藻的多肽得率可以达到(77.82±1.21)％.多肽的氨基酸组成分析结果显示,酶解制备得到的多肽基本上保持了原螺旋藻蛋白的氨基酸组成,氨基酸组成齐全,必需氨基酸占到氨基酸总量的43％以上,具有很高的营养价值.研究结果表明,复合蛋白酶水解螺旋藻制备多肽的工艺路线具有可行性.

为有效利用鸢乌贼资源,对酶解鸢乌贼组织蛋白制备酸溶性肽的工艺进行了研究.比较了不同蛋白酶对鸢乌贼组织蛋白水解能力的差异,确定胰蛋白酶为水解鸢乌贼组织蛋白的最佳蛋白酶类型.先后采用单因素和响应面试验对酶解工艺条件进行了系统的研究及优化.确定了胰蛋白酶水解鸢乌贼组织蛋白的最佳工艺条件为:蛋白浓度3％,加酶量4210 U/g蛋白,pH9.23,酶解温度52.3℃,酶解时间5h.在优化的工艺条件下,酸溶性肽的得率可以达到(74.02％±0.41％).此外,氨基酸分析结果表明,经酶解得到的酸溶性肽基本保持了原鸢乌贼组织蛋白的氨基酸组成,8种必需氨基酸含量丰富,约占氨基酸总量的38％.试验结果表明,采用胰蛋白酶水解鸢乌贼制备酸溶性肽的工艺具有可行性.

通过单因素试验、Plackett-Burman实验、最陡爬坡试验和响应面优化法确定百香果酸奶最佳发酵工艺.结果表明:以果汁添加量、白糖添加量和发酵温度为自变量,响应面法优化出百香果酸奶的最佳发酵工艺为白糖添加量7.4％,接种量0.1％,百香果果汁添加量5.5％,发酵温度42.7℃,发酵时间5h.在此条件下,酸奶感官评分约达到94.33分,与预测值(93.97分)相差较小.百香果酸奶的酸度、乳酸菌数和大肠杆菌数检测结果均符合食品安全国家标准.

目的:探讨粉碎工艺对仙人掌多糖得率及抗氧化活性的影响.方法:将仙人掌干粉粉碎至不同碎度后,比较其仙人掌多糖(Opuntia dillenii Haw.polysaccharides,ODPs)的得率、纯度、糖醛酸含量及抗氧化活性.结果:随着粉碎程度增加,ODPs得率、纯度及对O2-·和·OH的清除作用显著增加,表现出粗粉级、60目与100目级、200目与300目级3个等级(等级之间两两比较P＜0.05),但是糖醛酸含量无差异;300目碎度与粗粉比较,多糖得率、含量及对O2-·清除作用分别提高了100％、25％和150％.结论:结果提示,粉碎技术有助于提高仙人掌多糖的释放量,保持其品质及功效活性.

Use of natural polysaccharides in medicine and food has wide interest in research. In this study, we extracted and purified some polysaccharides from cactus Opuntia dillenii Haw. (ODP). Some preliminary functions of these products were characterized. Under the optimal purification conditions, the yield of ODP extracted from the 2–4 month-old Opuntia dillenii Haw. (T-ODP) was 30.60% ± 0.40%, higher than that of ODP from the 5–10 month-old materials (O-ODP) (18.97% ± 0.58%). The extracted ODP was purified by DEAE sepharose fast flow anion exchange and Sephacryl S-400 chromatography with four fractions obtained (ODP-Ia, ODP-Ib, ODP-IIa and ODP-IIb). Analysis with UV-vis chromatography indicated that ODP-Ia and ODP-IIa were relatively homogeneous molecules with a molecular weight of 339 kD and 943 kD, respectively. Results of infrared spectroscopy indicated that ODP, ODP-Ia, and ODP-IIa were acidic polysaccharides. Further, the antioxidant activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radical, hydroxyl radicals, and superoxide radical in vitro demonstrated that the T-ODP exhibited higher antioxidant activity than the O-ODP, and the purified fraction (ODP-Ia) was superior to the ODP. These results will offer a theoretical basis for further research on the structure-function relationship of ODP and the rational utilization of Opuntia dillenii Haw.

A strain of bacillus can degrade nitrite that was isolated from the cultured wastewater, which was named as Y1.The effect of initial concentration of nitrite,incubation time,pH,temperature and inoculation amount on degradation efficiencies was studied in the experiment.The optimal degrading conditions were:initial concentration of nitrite 10 mg/L,temperature of 30,pH 8.0,inoculation amount of 5 ,under the optimal conditions,the best degradation of nitrite mainly occurred in the logarithmic phase of the Bacillus sp.Y1 and the degrading efficiency could reach more than 93.04% after 9 h.In simulation test of polluted water in which the concentration of nitrite is 5 mg/L,the degradation rate of Y1 strain on the nitrite achieved at 98.50% for 72 h in 30OC via adding fermentation broth.The experimental results show that the Y1 strain can effectively degrade nitrite in aquaculture wastewater,and it can be used as a good bacteria species of microbial water treatment agent.

In order to study the extraction technology of flavonoids from Sclerophylla fruit,using THE single factor experiment and response surface methodology to investigate the impacts of ethanol volume fraction,solid-to-liquid ratio,extraction temperature and extraction time on the extraction rate of flavonoids from Sclerophylla fruit.Combined with the response surface interaction,the optimum extraction conditions of flavonoids from Sclerophylla fruit were an ethanol volume fraction of 50％,the solid-to-liquid of 1∶36 g/mL,extraction time of 2.5 h and extraction temperature of 83 ℃.Under these conditions the measured extraction rate of flavonoids was 2.107 mg/g,which was identical with predicted value(2.091 mg/g).

The extraction techniques of pigment from cherry tomato peel by solvent method were studied on the basis of single factor test and orthogonal test. The results suggested that the optimal technical condition was as follows: the best extraction technology was extracted solution of 90% ethanol + 0.5% citric acid(5∶1, V/V) in the mixture, the ratio of cherry tomato peel and extraction being 1 ∶14(g/m L), the p H was 4.0 and the extraction time was 70 min. This extraction technology, taking the ethanol as the extraction solvent, had features of low cost, easy operation and high safety, and had good prospects for development in the industry. The virgin skin pigment extract on the superoxide free radical scavenging effect and hydroxyl free radical scavenging effect and DPPH radical was positively correlated with concentration.

优化热水浸提法提取野生仙人掌多糖(Opuntia dillenii Haw.polysaccharides,ODPs)的工艺.在单因素实验的基础上,利用Box-Behnken实验和响应面分析法,研究提取温度、提取时间以及液料比对ODPs提取结果的影响;通过回归分析模拟得到二次多项式回归方程的预测模型;最后测定不同提取温度下ODPs蛋白质含量及DPPH自由基清除率.结果显示,最佳提取工艺为提取温度93℃,液料比62∶1,提取时间3.5h,由模型预测得率达到25.14％,验证实验结果为25.05％,与预测值较接近,表明模型具有较好预测性.提取温度、液料比、提取时间对野生仙人掌多糖得率的影响具有统计学意义(p＜0.001).提取温度为95℃时,多糖含量、DPPH自由基清除率都最高,但多糖中蛋白质含量也最高.说明响应面优化得到的提取工艺有利于提高ODPs得率,95℃的提取温度有利于增加多糖的抗氧化活性.

为探索果胶酶对番石榴果浆的出汁率的影响,以廉江本地番石榴为试材,采用单一果胶酶酶解方法,研究果胶酶添加量、酶解温度及酶解时间三个因素对番石榴出汁率的影响.结果表明,酶解的最佳工艺为:酶添加量0.05％、酶解时间4h、酶解温度为45℃.在此基础上进行验证试验,测得番石榴出汁率为81.54％,相比于未加果胶酶处理的空白试验,番石榴的出汁率提高了13.78％.

采用煮制法提取香菜中的有效成分,研究其体外抗氧化活性.运用硝酸铝显色法,检测总黄酮含量,并测定香菜提取液的总抗氧化能力以及其对羟自由基的清除能力.结果表明,芦丁在0.01～0.1 mg/mL (R2=0.999 1)质量浓度范围内,吸光度与浓度之间呈良好线性关系,香菜提取液的黄酮含量为1.73 mg/g鲜重;香菜具有显著的抗氧化活性,且呈剂量依赖性,总抗氧化能力为44.19 mg VC/g鲜重,其清除羟自由基的能力IC50=67.11 mg/mL.由此说明了香菜具有丰富的黄酮类化合物,且具有良好的体外抗氧化活性.

本实验研究了香菜对细菌的抑制作用.用无菌水将香菜汁进行稀释,研究不同浓度香菜汁的抑菌作用;并将100％香菜汁与香菜95％乙醇提取液对大肠杆菌的抑制作用进行比较;进一步研究温度、pH对香菜抑菌成分活性的影响.结果表明:香菜对大肠杆菌有较强的抑制作用,浓度越大,抑菌作用越大,反之越小;而香菜95％乙醇提取液对大肠杆菌无明显抑制作用;温度、pH对香菜汁稳定性显著;最后,介绍了香菜与其他抑菌物质抑菌效果的比较.

从自然发酵酸菜中分离出20株菌,经革兰氏染色后得到12株革兰氏阳性菌,对这12株菌进行形态学特征的观察、室温下产酸速率的测定以及乳酸定性后筛选出7株高产乳酸的乳杆菌,运用经典分类法对这7株高产乳酸菌株进行生理生化实验鉴定,初步鉴定该7株菌均为鼠李糖乳杆菌(Lactobacillus rhamnosus).通过牛津杯法研究该7菌株抑菌效果;通过对羟自由基、DPPH自由基和超氧阴离子自由基的清除效果来检测该7株菌的抗氧化性.结果表明,除了LR6菌发酵液对枯草杆菌无抑菌效果外,该7株菌对大肠杆菌,金黄色葡萄球菌,苏云菌杆菌均有抑菌作用,其他6株菌对枯草杆菌也有明显的抑菌效果;在抗氧化性方面,该7株菌的发酵液对羟自由基、DPPH自由基和超氧阴离子自由基具有明显清除作用,抗氧化效果显著.

以红肉火龙果果皮为原料,在单因素试验基础上,根据Box-Behnken试验设计原理采用三因素三水平相应面分析法,优化火龙果果皮色素提取条件;并通过测定其色素提取液对羟自由基(·OH)、超氧阴离子自由基(O2-·)和DPPH自由基的清除能力评价其抗氧化活性.结合实际可操作性得出红肉火龙果果皮色素提取的最优工艺条件是:选用体积分数80％乙醇+0.5％柠檬酸(体积比5∶1)为提取剂、液料比为10∶1 (mL∶g)、提取温度43℃、提取时间65min.火龙果果皮色素提取液对·OH、O2-·和DPPH·的清除作用明显,清除能力与色素提取液浓度呈一定的正相关关系,但其清除能力稍低于抗坏血酸.

The nitrite contamination and the variations of nitrite contamination under different conditions (room temperature, 4℃, cooked) in the 14 kinds of vegetables sold in Zhanjiang city were detected by N-Naphthylethylenediamine Dihydrochloride. Results showed that the content of nitrite in vegetables from high to low were leafy vegetables, melons vegetables, legumes, alliaceous vegetables. There were differences in the content of nitrite in the same type vegetables, but all far less than the limit value of 4.0 mg/kg. The changing rate of nitrite in the cold storage vegetables were significantly lower than those in room temperature. Under the condition of room temperature, cowpea could be saved for 1 d, the other three kinds of vegetables storage time was no more than 1 d, In the cold storage (4 ℃), beet and cabbage could be saved for 1 d, mustard and cowpea could be saved for 2 d. Under the condition of room temperature,the nitrite in cooked vegetables increased more rapidly than that in vegetables cooked placed in 4 ℃. The four kinds of generally vegetables cooked could be saved for 2~3 d under the 4 ℃ condition.