方便面中丙烯酰胺含量的检测

建立了方便面中丙烯酰胺的液相色谱-串联质谱分析方法.样品用水提取,酶解,净化.以水(0.1%甲酸):乙腈=90:10(V/V)为流动相经反相色谱柱分离后,采用液相色谱串联质谱多反应监测正离子模式检测,丙烯酰胺定性定量离子对为m/z72.10/55.00,同位素内标物定性定量离子对为75.00/58.00.空白样品及其添加实验结果表明,特征离子相对强度比值稳定,无基质干扰,结合保留时间可实现准确的定性定量,方法检出限为25μg/kg(S/N=3),样本添咖水平在5～200μg/kg时,平均回收率为68.1～90.1%,相对偏差(n=6)为4.3%～6.1%.该方法前处理简单、回收率高、精密度好,可满足方便面中丙烯酰胺的确证分析要求.     

稻草生物炭对铕的吸附行为及机理研究

以农业残留物为原料制备的生物炭被广泛应用于去除重金属, 这对于环境保护具有双重意义。本研究以稻草为原料制备了生物炭, 通过系列静态实验和光谱技术研究其对重金属铕(Eu)的吸附行为及机理。研究发现溶液pH显著影响生物炭对Eu(III)的吸附量, 但不改变吸附反应时间; 腐殖酸/富里酸(HA/FA)在pH<7.0的溶液中能促进生物炭对Eu(III)的吸附, 而在pH>7.0的溶液中则抑制Eu(III)的吸附; 吸附过程主要涉及共沉淀或内表面络合机制; 该吸附属于化学吸附, 且吸附速率受内颗粒扩散过程的限制。此外, Freundlich模型对该吸附拟合最好, Langmuir模型显示稻草生物炭对Eu(III)的最大吸附量为40.717 mg/kg, 这可能与生物炭的层状结构和丰富的官能团有关; 热力学分析表明该吸附是自发的吸热过程。这些发现有利于评估稻草生物炭在去除水中重金属方面潜在的应用价值。     

包装材料对水磨糯米粉品质的影响研究

通过贮存实验,对不同材料袋包装的糯米粉进行了加速试验,以含水率、脂肪酸值、霉菌和酵母菌菌落数、色泽为主要评价指标,研究了包装材料对袋装糯米粉品质的影响。实验结果表明,在相对湿度为90%,温度为37 ℃条件下,随着贮存时间的延长,糯米粉的含水率、脂肪酸值、霉菌和酵母菌菌落数、黄度增加,白度下降;包装材料的透湿、透氧率越大,对糯米粉品质评价指标的影响越明显,品质下降越显著。     

Genome-Wide Association Study Identifies a Rice Panicle Blast Resistance Gene,Pb2, Encoding NLR Protein

Rice blast is one of the main diseases in rice and can occur in different rice growth stages. Due to the complicated procedure of panicle blast identification and instability of panicle blast infection influenced by the environment, most cloned rice resistance genes are associated with leaf blast. In this study, a rice panicle blast resistance gene, Pb2, was identified by genome-wide association mapping based on the panicle blast resistance phenotypes of 230 Rice Diversity Panel 1 (RDP1) accessions with 700,000 single-nucleotide polymorphism (SNP) markers. A genome-wide association study identified 18 panicle blast resistance loci (PBRL) within two years, including 9 reported loci and 2 repeated loci (PBRL2 and PBRL13, PBRL10 and PBRL18). Among them, the repeated locus (PBRL10 and PBRL18) was located in chromosome 11. By haplotype and expression analysis, one of the Nucleotide-binding domain and Leucine-rich Repeat (NLR) Pb2 genes was highly conserved in multiple resistant rice cultivars, and its expression was significantly upregulated after rice blast infection. Pb2 encodes a typical NBS-LRR protein with NB-ARC domain and LRR domain. Compared with wild type plants, the transgenic rice of Pb2 showed enhanced resistance to panicle and leaf blast with reduced lesion number. Subcellular localization of Pb2 showed that it is located on plasma membrane, and GUS tissue-staining observation found that Pb2 is highly expressed in grains, leaf tips and stem nodes. The Pb2 transgenic plants showed no difference in agronomic traits with wild type plants. It indicated that Pb2 could be useful for breeding of rice blast resistance.     

不同熟制干制方法对方便面品质的影响

研究了水煮和蒸煮的熟制方法对方便面品质的影响,以及熟制后采用不同的干燥方法对面条进行脱水,选出一种最优的熟制干制方法.结果表明蒸煮方法较优于水煮,微波干燥优于热风、远红外和油炸干燥方法.通过正交实验得出微波干燥的最佳工艺条件为:微波干燥处理时间40s、微波功率210kW、微波频率920MHz和传道速率1m/min综合得分最高.     

超高压辅助酶法提取大米蛋白的研究

采用单因素和响应面分析的方法对碱性蛋白酶提取大米蛋白的条件进行优化,最终确定碱性蛋白酶提取条件为:加酶量1.4%,酶解温度58℃,酶解pH值8.3,酶解时间4 h及液固比9∶1.在此条件下,大米蛋白质提取率为70%.并在此基础上研究了超高压对碱酶提取大米蛋白质提取率的影响,试验表明在压力为400 MPa下,蛋白质提取率升高到78.72%.     

丁二酸酐酯化改性糯米淀粉的研究

目的 为了提高糯米淀粉的粘度,以达到标签胶的要求。方法 对糯米淀粉进行丁二酸酐酯化改性,通过单因素试验及响应面优化确定出最佳酯化条件,测定其理化性质,并对其进行结构表征。结果 丁二酸酐酯化改性糯米淀粉的最优工艺条件：丁二酸酐添加量（丁二酸酐占淀粉干基的质量百分比）为10.3%,酯化温度为41.5℃,酯化时间为2.0 h,pH为9.0,在此条件下制得的糯米淀粉胶的粘度较高,可达到61.6 Pa·s,且溶解性与溶胀度均有不同程度的提高。电镜与热力学性质分析表明,酯化后淀粉颗粒结晶结构受到破坏,表面粗糙,出现凹陷与裂缝。结论 经过丁二酸酐酯化后,糯米淀粉胶的粘度得到提高。     

胶凝化工艺对年糕水分分布状态和微观结构的影响

以糊化度、白度值、感官评分、蒸煮特性及质构特性为年糕的品质评价指标,研究胶凝化时间、胶凝化温度及胶凝化湿度对年糕品质的影响,并采用正交试验优化工艺条件.在优化条件下,研究在不同胶凝化时间下,年糕的水分分布和微观结构的变化.结果表明:胶凝化时间、胶凝化温度及胶凝化湿度分别通过影响年糕的胶凝化程度、速率及水分分布,改变年糕...     

Identification and Functional Analysis of the Caffeic Acid O-Methyltransferase (COMT) Gene Family in Rice (Oryza sativa L.)

Caffeic acid O-methyltransferase (COMT) is one of the core enzymes involved in lignin synthesis. However, there is no systematic study on the rice COMT gene family. We identified 33 COMT genes containing the methyltransferase-2 domain in the rice genome using bioinformatic methods and divided them into Group I (a and b) and Group II. Motifs, conserved domains, gene structure and SNPs density are related to the classification of OsCOMTs. The tandem phenomenon plays a key role in the expansion of OsCOMTs. The expression levels of fourteen and thirteen OsCOMTs increased or decreased under salt stress and drought stress, respectively. OsCOMTs showed higher expression levels in the stem. The lignin content of rice was measured in five stages; combined with the expression analysis of OsCOMTs and multiple sequence alignment, we found that OsCOMT8, OsCOMT9 and OsCOMT15 play a key role in the synthesis of lignin. Targeted miRNAs and gene ontology annotation revealed that OsCOMTs were involved in abiotic stress responses. Our study contributes to the analysis of the biological function of OsCOMTs, which may provide information for future rice breeding and editing of the rice genome.     

利用多时相HJ卫星CCD遥感影像提取嘉祥县秋收作物

作物种植面积对调整农业结构、制定区域粮食安全政策有着十分重要的意义。本文以山东省嘉祥县为研究区,利用3景不同时相的HJ卫星CCD遥感数据,结合野外调查样本,通过分析研究区主要秋收作物(玉米、棉花和水稻)在不同生育期的光谱特征和归一化植被指数(NDVI)的特点,对分类影像进行系列阈值分割、掩膜处理,最后利用决策树算法成功提取了山东省嘉祥县的玉米、棉花和水稻的种植面积,总体精度分别达到93.31%、89.41%、95.82%。