猪肉助色剂的研究及配方优化

研究不同异抗坏血酸钠、烟酰胺、茶多酚添加量对猪肉色差、发色率、肌红蛋白存在形式比例及亚硝酸钠残留量的影响,并通过正交交互分析方法来确定减少亚硝酸钠用量的最佳发色配方。结果表明,亚硝酸钠的添加量为100mg/kg时,最佳助色剂配方为:异抗坏血酸钠400mg/kg、烟酰胺500mg/kg、茶多酚300mg/kg。在此条件下,a*为12.78,发色率为56.67%,经过腌制,猪肉在感官上表现为鲜艳的玫瑰红色,发色均匀,且在保藏期间长期不退色。     

基于真空压差膨化技术的无花果脆片无硫护色工艺优化研究

研究了无花果果片在真空压差膨化条件下的最佳护色工艺条件,解决无花果脆片干燥过程中的变色问题。在单因素试验条件下挑选柠檬酸、D-异抗坏血酸钠、L-半胱氨酸3种护色剂。根据Box-Behnken的试验设计原理,设计响应试验,进行交互作用分析。试验结果表明,柠檬酸、D-异抗坏血酸钠、L-半胱氨酸的交互作用对无花果脆片的总色差ΔE的影响显著。试验得到的最佳的无硫护色工艺条件为:柠檬酸0.42%、D-异抗坏血酸钠0.62%、L-半胱氨酸0.42%,最佳条件下ΔE的实测值为5.815。     

风鹅腌制优化工艺技术的研究

采用正交试验设计探讨了蛋白酶种类、腌制时间、腌制温度对风鹅风味和游离氨基酸产生及硝酸钠、亚硝酸钠、异抗坏血酸钠、乳酸用量和腌制时间对风鹅发色的影响，结果表明蛋白酶种类、腌制时间、腌制温度对风鹅风味及游离氨基酸产生及硝酸钠、亚硝酸钠、异抗坏血酸钠、乳酸用量和腌制时间对风鹅的发色均有显著性的影响。其最佳腌制条件如下：蛋白酶种类为毛霉蛋白酶＋青霉蛋白酶＋木瓜蛋白酶，腌制时间6h，腌制温度19℃，硝酸钠、亚硝酸钠、异抗坏血酸钠和乳酸用量分别为250mg/kg、100mg/kg、200mg/kg和200mg/kg。     

灌肠制品中亚硝酸钠残留量及肉品发色率预测模型的建立

通过对亚硝酸钠添加量、异抗坏血酸钠添加量及原料肉中总色素含量与亚硝酸钠残留量及肉品发色率之间的关系的研究,对实验数据进行了统计分析,建立了本研究范围内的亚硝酸钠残留量及肉品发色率的预测模型:Y1=17.082+0.181X1-0.017X2-0.026X3和Y2=58.466+0.007X1+0.033X2+0.022X3,其中Y1、Y2、X1、X2、X3分别代表亚硝酸钠残留量(mg/kg)、肉品发色率(%)、亚硝酸钠添加量(mg/kg)、异抗坏血酸钠添加量(mg/kg)、原料肉中的总色素含量(mg/kg)。     

雪梨多酚氧化酶酶学特性及其果汁褐变控制技术研究

雪梨在加工过程中极易发生酶褐变,为抑制雪梨汁的酶褐变,试验以雪梨为原料制备多酚氧化酶(Polyphenol oxidase,PPO)粗酶提取液,加入邻苯二酚为底物,采用分光光度法对其PPO的酶学特性及不同护色剂对PPO活性的影响进行了研究;并选择L-半胱氨酸、D-异抗坏血酸钠、抗坏血酸3种添加剂对雪梨汁进行护色,通过响应面优化试验确定雪梨汁最优护色组合。结果表明:雪梨PPO的最适pH为4.5,最适温度为30 ℃;雪梨PPO具有一定的热稳定性,随着温度的提高,抑制PPO活性所需要的时间逐渐减少;雪梨PPO催化底物邻苯二酚的酶促反应动力学与米氏方程高度符合,最大反应速率Vmax=217.39 U/min,米氏常数Km=0.152 mol/L。雪梨汁加工的最优护色剂组合为:6.56 mmol/L的L-半胱氨酸、4.58 mmol/L的D-异抗坏血酸钠和6.18 mmol/L的抗坏血酸,在此条件下对雪梨汁褐变的抑制率可达90.82%。     

肉腌制工艺参数研究

通过添加腌制剂、助发色剂等食品添加剂对猪肉进行湿法腌制,并对腌制成品的发色率、肉中亚硝酸钠残留量进行测定,得到了湿法腌制肉的最佳工艺参数,即食盐用量为2.5%、复合磷酸盐用量为0.3%、硝酸钠用量为0.04%、亚硝酸钠用量为0.009%、抗坏血酸用量为0.02%、腌制温度为4℃、腌制时间为32h,该结论可为工业生产腌制肉提供参考。     

发色助剂对熏马肉色泽及亚硝酸钠残留的影响

试验通过添加抗坏血酸、α-生育酚和烟酰胺对马肉进行腌制,经滚揉和烟熏处理后测定其红度(a*)、发色率及亚硝酸钠残留量。在单因素试验的基础上,采用正交试验设计,确定这3种发色助剂的最佳混合比例。结果表明:当抗坏血酸、α-生育酚、烟酰胺添加量分别为:500、300、300 mg/kg时,熏马肉的发色效果好且亚硝酸钠残留量最低,为9.269μg。     

风鸭腌制新技术

采用正交试验设计，探讨了蛋白酶种类、腌制时间、腌制温度对风鸭风味和游离氨基酸产生，及亚硝酸钠、异抗坏血酸钠、乳酸用量和腌制时间对风鸭发色的影响。结果表明，蛋白酶种类、腌制时间、腌制温度对风鸭风味及游离氨基酸产生，及亚硝酸钠、异抗坏血酸钠、乳酸用量和腌制时间对风鸭的发色，均有显著性的影响。其最佳腌制条件：蛋白酶种类为毛霉蛋白酶 青霉蛋白酶 木瓜蛋白酶，腌制时间5h，腌制温度18℃，亚销酸钠、异抗坏血酸钠和乳酸用量分别为100mg/kg、300mg/kg和250mg/kg。     

火龙果果汁饮料护色工艺

选用D-异抗坏血酸钠、茶多酚、VE、无水亚硫酸钠和植酸5种抗氧化剂为护色剂进行试验,通过火龙果汁色泽的保持率,评判其护色效果,同时对3种灭菌方式进行对比研究。实验结果表明:煮沸灭菌结合添加D-异抗坏血酸钠的护色效果最佳,当D-异抗坏血酸钠的添加量为0.013%时,保持率为最大达到77.42%。     

包装材料和L-抗坏血酸对酿造酱油色泽的影响

针对酿造酱油在贮存过程中易出现色泽加深、色调下降的现象,比较了不同的包装材料和不同剂量L-抗坏血酸对酱油的色率和红色指数的影响。实验结果表明:采用内衬黑色膜的聚乙烯包装材料、添加L-抗坏血酸等措施,可有效稳定贮藏阶段袋装酱油的色泽。     

磷酸化亚硝基猪血红蛋白代替亚硝酸盐部分作用及其对乳化肠品质的影响

为降低亚硝酸盐的添加对乳化肠安全品质的影响,研究磷酸化亚硝基血红蛋白（phosphorylated nitrosohemoglobin,P-NHb）替代亚硝酸钠（NaNO2）对乳化肠的色泽、抗氧化能力和感官品质等的影响。结果表明,随贮存时间的延长,P-NHb对乳化肠挥发性盐基氮的影响与NaNO2无显著差异（P＞0.05）;添加P-NHb可减少乳化肠pH值下降;P-NHb组亚硝酸盐残留量最高为（6.22±0.01）mg/kg;P-NHb组和NaNO2组的硫代巴比妥酸反应物值最高分别为（0.62±0.01）mg/kg和（0.67±0.01）mg/kg,表明P-NHb能够抑制脂肪氧化,其抗氧化效果优于NaNO2;P-NHb可赋予乳化肠理想色泽;P-NHb组整体可接受度与NaNO2组无显著差异（P＞0.05）。综上所述,P-NHb可改善乳化肠色泽,降低亚硝酸盐残留,具有较强的抗氧化作用,可以作为一种新型天然色素,考虑其代替NaNO2在肉制品中使用。     

硝酸钠对发状念珠蓝细菌生长的促进作用

研究了添加不同浓度的藻类培养常用无机氮源NaNO,对发状念珠蓝细菌生长、光合速率、胞外多糖积累、蛋白质含量、色素含量以及磷酸根与硝酸根消耗的影响。结果表明,添加NaNO3对发状念珠蓝细菌的生长具有促进作用,2．0g／L的NaNO3对细胞生长的促进作用最大,藻细胞干重达到0．83g／L,净光合速率最大,随着添加浓度的继续增加,细胞干重达到平衡。细胞呼吸作用在NaNO3为2．5g／L时最大。细胞蛋白质含量随NaNO3浓度的增大逐渐升高,与此相应,细胞对NO3^-与PO43^-的利用率也逐渐增高。在不同NaNO3浓度下,培养15d后的培养液的pH值差异不显著,但是添加组的最终pH值明显比不加硝酸钠的空白对照要小。     

不同添加物对菠萝蛋白酶酶活稳定性和抑制作用的影响

选择几种添加物于菠萝蛋白酶酶液中,并在不同pH值缓冲液中保存,定期测定其酶活力,研究添加物及缓冲液对菠萝蛋白酶的稳定性和抑制作用的影响。结果显示:VB1、L-半胱氨酸、异抗坏血酸钠、NaCl对菠萝蛋白酶酶活均有促进作用。保存的第1天,添加0.100g/100mL VB1的酶活比对照组提高了22%。添加0.2g/100mLL-半胱氨酸、0.005g/100mL异抗坏血酸钠的酶活比对照组分别提高了60%、37%。而NaNO2、乙酸锌、ZnCl2对菠萝蛋白酶酶活都有一定的抑制作用。随着NaNO2浓度的升高,抑制作用逐渐增强。乙酸锌、ZnCl2能将菠萝蛋白酶酶活分别降低到原酶活力的11%、1%。而KCl和NaNO3对菠萝蛋白酶活力影响不显著。     

Nitrite-induced injury of Listeria monocytogenes and the effect of selective versus nonselective recovery procedures on its isolation from frankfurters

Sodium nitrite (NaNO2) is used as a curing agent in frankfurters. Although previous studies have documented the bacteriostatic abilities of NaNO2 toward Listeria monocytogenes, few if any studies have been conducted that consider the possibility of sublethal injury to L. monocytogenes by exposure to NaNO2. The goals of this study were to determine whether NaNO2 has the ability to injure L. monocytogenes, to determine whether nitrite injury is reversible, and to compare the recovery of L. monocytogenes from frankfurters containing nitrite with Listeria repair broth (LRB) and University of Vermont modified Listeria enrichment broth (UVM). NaNO2, when used at concentrations of 100 and 200 ppm, was found to injure L. monocytogenes. The injury was completely reversible, or growth of uninjured Listeria occurred in LRB when injury was between 98.5 and 98.7%. However, total recovery was not observed in LRB when injury exceeded 99%. UVM was unable to reverse the effects of nitrite-injured L. monocytogenes. With respect to time, inoculum, and meat type, LRB was found to be consistently superior to UVM at recovering L. monocytogenes from frankfurters. Nitrite injury might be a factor influencing detection and recovery of L. monocytogenes from frankfurters.     

“保色红”对广式香肠腌肉色形成和保持的影响

“保色红”是一种复合的肉制品亚硝酸钠助发色剂 ,分别对添加“保色红”的模拟广式香肠腌制、加热和光照时的L 、a 、b 值进行测定 ,结果实验组a 值明显高于对照组 ,说明“保色红”能促进亚硝酸钠与肌肉的发色反应 ,具有稳定腌肉红色 ,增强香肠颜色稳定性的作用。     

硝酸钠对发状念珠蓝细菌CO2间断通气培养的影响

研究了不同浓度NaNO3对CO2间断通气培养与NaHCO3添加培养条件下发状念珠蓝细菌生长、光合速率、胞外多糖积累、蛋白质含量、色素含量、磷酸根与硝酸根消耗、细胞固碳率以及光合效率的影响。结果表明,在CO2通气条件下添加NaNO3能够显著促进发状念珠蓝细菌的生长。2.0 g/L的NaNO3为最佳浓度,干重达到1.56 g/L,为对照的2.29倍,呼吸与净光合速率达到最大。当NaNO3浓度达到2.5 g/L时,藻细胞干重停止增加。细胞叶绿素含量随着NaNO3浓度的增加而增加。硝酸钠添加组胞外多糖的含量相比不添加组均下降,但添加组的多糖含量随NaNO3浓度的增加而增加。细胞蛋白质含量随NaNO3浓度的增加而增加,在2.0 g/L时达到最高。与生物量的增加相对应,细胞对两种盐分的利用率在NaNO3为2.0 g/L时达到最大。CO2通气培养时添加NaHCO3可进一步促进细胞的生长。在两种碳源同时存在时,NaNO3对细胞的生长促进作用与单一碳源存在培养时类似。     

The effects of temperature, pH, sodium chloride and sodium nitrite on the growth of Listeria monocytogenes.

An automated turbidimetric system using multiwelled plates was used to examine the effects of different combinations of NaCl (0.5-8.0% w/v), NaNO2 (0-400 micrograms/ml) pH (4.6-7.4) and temperature (5-30 degrees C) on the growth of Listeria monocytogenes in tryptone soya broth. The data presented clearly illustrate the combinations that permit visible growth of the organism. The ability of L. monocytogenes to grow at low pH levels was strongly influenced by incubation temperature as well as NaNO2 concentration. At 20 degrees C and below, no visible growth was detected, even with 50 micrograms/ml NaNO2 at pH 5.3 (or below) within 21 days. At pH 6.0 and above, NaNO2 had little effect in delaying visible growth except at higher concentrations and also at lower incubation temperatures.     

软枣猕猴桃总黄酮含量测定的方法研究

选用ZrOCl2比色法、NaNO2-Al(NO3)3比色法、AlCl3比色法以及HPLC法测定软枣猕猴桃总黄酮含量,通过对黄酮粗提液和芦丁标准品与不同显色剂反应后进行200～600nm波长扫描,根据扫描结果确定各种反应的适合波长并进行定量分析比较。结果表明,NaNO2-Al(NO3)3比色法与AlCl3比色法不适合软枣猕猴桃总黄酮测定。在284nm波长处,ZrOCl2比色法的线性方程Y=0.0114X-0.0001,R2=0.9991,平均加样回收率为99.4%,RSD=1.61%(n=5)。ZrOCl2比色法是一种快捷、准确的检测方法,适用于软枣猕猴桃总黄酮含量测定。     

Denitrification mechanism of NaOH in the presence of carbon

We tested a mixture of NaOH and carbon and found it to react rapidly with NO gas, thus demonstrating a promising new method of flue gas denitrification (FGD). We determined the reaction products: gas phases were analyzed by GC-MS and NOx meter, and solid residues were analyzed by X-ray diffusion (XRD) and chemical analysis. The reaction process was clearly divided into two stages. In the first stage, the reaction proceeded extremely rapidly, with NO almost completely removed. The mechanism describing this stage consists of a series of reactions of NaOH and NO in the presence of carbon. The main conversion of sodium in this stage is proposed to be: NaOH-->NaNO3 (and NaNO2)-->Na2O2-Na2CO3. The pyrolysis of NaNO3 was examined and carbon was found to have the ability to reduce NOx emission during this process. In the second stage, NO reduction proceeds slowly and stabilizes at a constant value. The mechanism behind this stage is considered to be the reaction of carbon with NO in the presence of Na2-CO3 as catalyst. Quantitative study of the reaction system demonstrated that the total amount of denitrified NO is proportional to the amount of carbon and that the denitrified NO in the first stage is proportional to the amount of NaOH.     

Heme pigment content in meat as affected by the addition of curing agents

The effects of curing agents on the content of heme pigments (HP) in meat were examined. Minced porcine skeletal muscle was treated with NaCl, NaNO(2) and sodium ascorbate (NaAsA), separately or in combination, and stored at 2-3°C for 7 days. HP content decreased with increase in NaCl concentration and the decrease was about 50% and 80% at NaCl concentrations of 2% and 10%, respectively. Two percent NaCl prevented HP destruction, when previously mixed with 100 ppm NaNO(2) or 0·1% NaAsA. Although some decrease in HP content was noted following application of a mixture of NaCl, NaNO(2) and NaAsA, it was essentially the same as that of the control during 7 days of refrigerated storage. In a model solution containing the same curing agents as those applied to the meat. NaCl had no effect and myoglobin (Mb) content remained constant during storage. From the present results, endogenous muscle constituents appear to act in concert with NaCl to bring about a decrease in HP content.