碱液提取离子色谱法测定水产品中多聚磷酸盐的研究

建立了碱液提取水产品中多聚磷酸盐并同时测定焦磷酸盐、三聚磷酸盐和六偏磷酸盐的离子色谱法。以3mol/L NaOH溶液为提取液,回收率达90%以上,有效阻断了多聚磷酸盐的水解。在AS11-HC阴离子色谱柱上,焦磷酸盐、三聚磷酸盐和六偏磷酸盐分离度良好,在质量浓度为1.0～100.0mg/mL的范围内,其浓度与峰面积成良好的线性关系。在优化的色谱条件下,三种多聚磷酸盐的测定低限分别为：焦磷酸3.0mg/kg,三聚磷酸盐为3.0mg/kg,六偏磷酸盐为10.0mg/kg。以鲢鱼为空白样,添加三个浓度（1.0、10.0、50.0mg/mL）进行精密度和回收率实验,RSD在4.0%以下,回收率在95%～100%。     

采用离子色谱检测肉及肉制品中多聚磷酸盐

采用离子色谱技术同时检测肉及肉制品中的正磷酸盐、焦磷酸盐、三聚磷酸盐和三偏磷酸盐成分。对建立的方法进行检出限、定量限和最佳线性范围的确定,并进行加标回收和精密度测定,以及实际应用效果评价。4种磷酸盐分离度良好,正磷酸盐、焦磷酸盐、三聚磷酸盐、三偏磷酸盐检出限分别为0.01、0.15、0.15、0.15mg/L,定量限分别为0.05、0.5、0.5、0.5 mg/L,分别在0.05~200、0.2~200、0.2~200、0.2~200 mg/L浓度内,呈良好线性关系。在3个浓度水平加标,其中正磷酸盐1 000、2 000、5 000 mg/kg,焦磷酸盐、三聚磷酸盐和三偏磷酸盐50、100、200 mg/kg,加标回收率为83.2%~101.9%,相对标准偏差(relative standard deviation,RSD)小于2.02%。用建立的方法对市售产品进行检测分析,结果可以满足市售肉及肉制品样品的检测需求。     

在线超滤-离子色谱法检测鱼子酱中的多聚磷酸盐

目的建立在线超滤一离子色谱法检测鱼子酱中多聚磷酸盐的方法。方法利用超纯水超声提取鱼子酱中的多聚磷酸盐,经在线超滤装置自动在线净化样品,由电导检测器检测样品中的多聚磷酸盐含量。结果该方法检出限(LOD)为10 mg/kg。标准加入法测定所有被测物的高、中、低三个浓度加标水平的回收率范围分别为正磷酸盐95%~120%、焦磷酸盐68%~75%、三聚磷酸盐85%~88%、三偏磷酸盐100%~107%,相对标准偏差(RSD)在0.38%~1.36%之间。4种被测物在1~80μg/mL范围内线性良好,R~2均大于0.999。结论该方法稳定、快速、精密度高、线性范围宽,适合鱼子酱中多聚磷酸盐的含量测定。     

离子色谱法测定燕窝中的多聚磷酸盐

目的 利用离子色谱(IC)建立一种可以一次进样同时分离测定燕窝中的正磷酸盐、焦磷酸盐、三聚磷酸盐和三偏磷酸盐的分析方法。方法 将燕窝磨成粗粉, 经超声萃取, 再用氯仿沉淀蛋白, 过C18柱后采用AS11-HC离子色谱柱(4 mm?250 mm), 流动相为NaOH和超纯水, 梯度洗脱, 流速为1.0 mL/min, 电导抑制检测。结果 该方法在0.5~100 mg/L范围内有良好的线性关系, 相关系数均大于0.9996,在添加实验中, 方法的回收率在89.5%~106.3%之间 ,相对标准偏差为0.9%~7.3%。正磷酸盐、焦磷酸盐、三聚磷酸盐和三偏磷酸盐的检测限分别为0.2、0.05、0.05、0.1 mg/kg。结论 该方法检测限低, 灵敏度和重现性高, 抗干扰能力强, 结果准确, 操作方便快速, 适合燕窝中多聚磷酸盐的测定。     

离子色谱法同时测定海产品中的硝酸盐、亚硝酸盐和多聚磷酸盐

建立超声辅助提取离子色谱法测定海产品中硝酸盐、亚硝酸盐和多聚磷酸盐（包括正磷酸盐、焦磷酸盐、三聚磷酸盐和三偏磷酸盐）含量的方法,对样品中硝酸盐、亚硝酸盐和多聚磷酸盐的稳定性进行研究,并采用该法对典型海产品中的硝酸盐、亚硝酸盐和多聚磷酸盐含量进行测定。结果表明：采用亲水性阴离子交换分离柱,KOH溶液为淋洗液作梯度淋洗,硝酸盐、亚硝酸盐和多聚磷酸盐的线性相关系数在0.998 1～0.999 8之间,回收率为79.2%～93.6%,相对标准偏差小于8.2%。经处理后的样品中,焦磷酸盐、三聚磷酸盐和三偏磷酸盐的总量在14 h内保持稳定。利用该法对东海地区典型海产品中的硝酸盐、亚硝酸盐和多聚磷酸盐进行了测定,结果显示不同品种的海产品中硝酸盐、亚硝酸盐和多聚磷酸盐含量分布有较大差异,除其中一份虾制品中多聚磷酸盐含量超过5 g/kg外,其余均符合国家限量标准。     

肌肉中多聚磷酸盐水解的研究进展

该文主要阐述了添加到肌肉中的多聚磷酸盐的水解及其影响因素的研究现状。三聚磷酸盐首先水解成焦磷酸盐和单磷酸盐,生成的焦磷酸盐进一步水解成单磷酸盐,添加的焦磷酸盐则直接水解成单磷酸盐。多聚磷酸盐在肌肉中主要是通过相应的水解酶水解,受到较多物理化学因素影响。     

乳酸钠对铜绿假单胞菌生长的影响

为探讨乳酸钠对铜绿假单胞菌(Pseudomonas aeruginosa)的特定抑制作用,揭示乳酸钠质量浓度与介质pH值水平影响乳酸钠抑菌效果的规律,以营养肉汤培养基为介质,按照乳酸钠质量浓度(0、0.2、0.5、1.0、1.5、2.0g/100mL)单因素试验及乳酸质量浓度与介质pH值(4.0～6.2)的两因素交互试验设计,25℃恒温培养。结果表明：在适当的pH值范围内,乳酸钠(NaL)表现出良好的抑菌效果：当介质pH值小于NaL质量浓度的抑菌临界pH值时,NaL抑菌效果与其质量浓度成正比,介质pH4.8,抑菌效果2.0g/100mL NaL＞1.0g/100mL NaL＞0.5g/100mL NaL。NaL质量浓度一定,其抑菌效果与介质pH值成反比。     

青岛市售冻虾及冻虾仁中磷酸盐残留量的调查分析

通过对青岛市售冻虾及冻虾仁中磷酸盐残留量的调查分析,为水产品的质量安全及风险监测提供一定的科学依据。本文采用离子色谱法,先后对水产样品中正磷酸盐、焦磷酸盐、三聚磷酸盐、三偏磷酸盐含量进行测定。采集水产样品共计265份,其中冻虾64份、冻虾仁201份。结果表明,少数数水产样品中正磷酸盐含量较高,多聚磷酸盐中焦磷酸盐和三聚磷酸盐含量较高;冻虾及冻虾仁中正磷酸盐含量不存在显著性差异(P>0.05),多聚磷酸盐含量均存在一定的显著性差异(P<0.05),冻虾仁中多聚磷酸盐含量明显高于冻虾。     

多聚磷酸盐在罗非鱼片中扩散规律的研究

将罗非鱼片用不同浓度的多聚磷酸盐溶液浸泡处理,研究了多聚磷酸盐在鱼片中的扩散规律。结果表明,磷酸盐在鱼片和磷酸盐溶液体系中呈双向扩散,在2%、4%、6%浓度的溶液中,扩散分2个阶段进行,初始阶段磷酸盐由鱼片向溶液扩散明显,最后阶段由溶液向鱼片扩散明显。表现为,鱼片中磷酸盐含量随浸泡时间的延长,先下降,再上升,最后达到平衡的扩散规律,最低时其含量分别为:2.99、3.31和3.50g/kg;平衡时其含量分别为:4.51、4.99和6.20g/kg;在0%和0.5%浓度的溶液中,由鱼片向溶液中扩散占优势,鱼片中磷酸盐含量不断下降,最后达平衡。平衡时其含量分别为1.79g/kg和2.37g/kg。     

不同磷酸盐对猪肌肉嫩度及保水性的影响

以猪背最长肌为原料,选择不同浓度多聚磷酸盐、六偏磷酸盐和焦磷酸盐对样品进行盐水注射和滚揉处理,采用正交试验设计,测定肌肉嫩度、滴水损失率、离心损失率、蒸煮损失率,研究磷酸盐对肌肉嫩度及保水特性的影响。结果表明：不同磷酸盐对肌肉嫩度及保水性的不同指标影响不同,其中多聚磷酸钠对肌肉嫩度有显著影响(P ＜ 0.05)。当焦磷酸钠:多聚磷酸钠:六偏磷酸钠为0.3%:0.3%:0.2% 时,其嫩化效果最明显。多聚磷酸盐对滴水损失率、蒸煮损失率有影响显著(P ＜ 0.05)。依据蒸煮损失率确定的磷酸盐最佳组合为0.2% 焦磷酸钠-0.3%多聚磷酸钠-0.2% 六偏磷酸钠。     

响应面法优化复合磷酸盐提高鱼糜的保水性

通过响应面试验设计研究了复合磷酸盐对鱼糜保水性的影响.分析结果表明:磷酸三钠、三聚磷酸钠以及磷酸三钠与焦磷酸钠的交互作用对鱼糜的蒸煮损失具有显著性影响.并确定了鲤鱼鱼糜具有最低蒸煮损失时各磷酸盐的添加量分别为:磷酸三钠0.25 g/kg,三聚磷酸钠1.75 g/kg,焦磷酸钠0.86 g/kg,六偏磷酸钠1.47 g/kg.     

磷酸盐-大豆分离蛋白联合处理对草鱼肌原纤维蛋白凝胶化的影响

为探讨磷酸盐(三聚磷酸钠、六偏磷酸钠、焦磷酸钠(tetrasodium pyrophosphate,TSPP))和大豆分离蛋白(soy protein isolate,SPI)对草鱼肌原纤维蛋白凝胶化的影响,采用热处理方法,将不同质量浓度的磷酸盐、SPI与草鱼肌原纤维蛋白混合制成凝胶.用黏度、嫩度、持水性、显微结构和粗...     

THE INFLUENCE OF POLYPHOSPHATE MARINATION ON SIMMENTAL BEEF SHEAR VALUE AND ULTRASTRUCTURE

The beef semitendinosus muscles were marinated for 1, 2 or 3 days with every polyphosphate at concentration of 1, 3 and 5%. Disodium dihydrogen pyrophosphate significantly increased ( P <  0.01) soluble collagen content compared with the other polyphosphates; tetrosodium pyrophosphate (TSPP) and sodium hexametaphosphate (SHMP) disrupted myofibrillar structure completely; Z-disks disappeared under transmission electron microscope (TEM); and myofibril bundles collapsed together. Sodium tripolyphosphate (STPP) disrupted myofibrillar structure as well, but Z-disks were still perceptible under TEM. TSPP dissolved perimysium into collagen fibers and collagen fibrils, which arranged loosely and looked like dispersed silk. Perimysium was separated into collagen fibers and collagen fibrils by STPP and SHMP, but collagen fibrils were in close contact with each other. Polyphosphates all decreased shear force significantly compared with controls ( P <  0.05).

PRACTICAL APPLICATIONS

The tenderness and juiciness of meat are the most important focus of consumers. Food additives, especially polyphosphates, are generally added into fresh retail cuts as well as further processed products to improve water-holding capacity and tenderness by meat industries. The article compared the different effects of polyphosphates and the effect of concentration on the ultrastructure and shear force of meat samples, thereby offering a theoretic guidance for the practical application of polyphosphates.     

Effect of polyphosphates on the survival of pre-stressed Salmonella typhimurium cells in frozen chicken meat

Six different commercial polyphosphate preparations were evaluated for their lethal efficacies against inoculated pre-stressed stationary phase cells of Salmonella typhimurium LT₂ in frozen comminuted poultry meat subsequently stored at ?18°C for 28 days. At the 0·3% wt/wt concentration used, Puron 6040 was found most potent, achieving approximately 2 log cycle viability reduction, closely followed by Fibrisol N7 and sodium tripolyphosphate with 94·7% and 84·5% viability reductions, respectively. Curaphos 700 instant and tetrasodium pyrophosphate No. 7 both exhibited similar potency magnitudes of approximately 70% viability reduction each, while acid sodium pyrophosphate was the least potent. The polyphosphates slightly altered sample pH values and aided fluid retention without any detectable influence on the a_w value. The findings demonstrate the potential antimicrobial benefits derivable from polyphosphates incorporation coupled with the conferrable textural advantages. It is considered that the observed potencies are influenced by chemical factors including chain length, pH and the subsequent relative stabilities of the polyphosphates in the menstruum system.     

复合磷酸盐和木瓜蛋白酶对猪肉脯嫩化效果对比研究

主要对复合磷酸盐和木瓜蛋白酶嫩化猪肉脯的效果进行了对比研究。先利用响应面法优化得到了复合磷酸盐嫩化猪肉脯的最佳工艺条件:焦磷酸钠浓度0.3085g/100 mL;三聚磷酸钠浓度0.2102g/100 mL;六偏磷酸钠浓度0.2571g/100 mL;嫩化时间8h。然后利用正交试验优化得到了木瓜蛋白酶嫩化猪肉脯的最优工艺条件:木瓜蛋白酶用量360U/g,作用温度70℃,作用时间20 m in。最后对这两种嫩化方法的嫩化效果进行了对比,结果发现,复合磷酸盐和木瓜蛋白酶对猪肉脯剪切力下降的幅度分别为26.8%和46.9%,说明木瓜蛋白酶的嫩化效果更好,因此选择木瓜蛋白酶作为对猪肉脯的嫩化方法。     

Short communication: Combined antimicrobial activity of reuterin and diacetyl against foodborne pathogens

Reuterin (β-hydroxypropionialdehyde) is a broad-spectrum antimicrobial substance produced by some strains of Lactobacillus reuteri during anaerobic fermentation of glycerol. Some of these strains are able to survive and produce reuterin in cheese and yogurt when added as adjuncts to the starter. Similarly, in fermented dairy foods, other inhibitory compounds such as lactic acid and diacetyl are produced during fermentation. In this work, we studied the combined effect of reuterin and diacetyl under different pH conditions against Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes. Results from agar spot assays showed that the antimicrobial activity of reuterin-producing strains against the gram-negative bacteria tested was enhanced as the concentration of diacetyl increased to 50 mg/kg, and was higher under acidic conditions (pH 5.0) for the 3 pathogenic strains. The combination of reuterin and diacetyl had an additive effect against L. monocytogenes only at diacetyl concentrations of 50 mg/kg and pH 5.0. In addition, growth kinetics studies showed that the combination of 1 activity unit (AU)/mL of reuterin with 100 mg/kg diacetyl increased the lag time of the 3 pathogens. In milk, synergistic antimicrobial activity was observed with the combination of 1 AU/mL reuterin and 50 or 100 mg/kg of diacetyl on the gram-negative strains tested, and with 1 AU/mL reuterin and 100 mg/kg of diacetyl on L. monocytogenes. The greatest inhibition of the 3 pathogens was achieved in acidified milk at pH 5.0 with reuterin (1 AU/mL) and diacetyl (100 mg/kg). Based on these results, the combination of reuterin and diacetyl in acidified dairy products could be a promising strategy to control food pathogens in these products.     

离子色谱法研究多聚磷酸盐在肌肉中的动态水解变化

采用免试剂离子色谱法同时检测焦磷酸四钠（tetrasodium pyrophosphate,TSPP）、三聚磷酸钠（sodiumtripolyphosphate,STPP）和混合磷酸盐（m（TSPP）∶m（STPP）∶m（六偏磷酸钠）=3∶4∶3）在猪背最长肌、鱼背侧肌以及鸡胸大肌中的水解情况。结果表明,多聚磷酸盐在肌肉中的水解情况存在着差异。单一的TSPP在鸡胸大肌中的水解速率最快,TSPP在猪背最长肌中水解量比在鱼背侧肌中多。将STPP或混合磷酸盐加入到肌肉中,均在猪背最长肌中的水解速率最快,在鸡胸大肌中次之,在鱼背侧肌中最慢。本研究探索多聚磷酸盐在不同物种肌肉中的动态变化,为调控多聚磷酸盐的水解进程,指导多聚磷酸盐在不同物种肌肉中的合理添加提供了理论依据。     

EFFECT OF POLYPHOSPHATES AND NaCl ON AEROMONAS HYDROPHILA K144

Polyphosphates are multifunctional ingredients added to many foods, particularly meat products. In addition to their moisture-binding properties, polyphosphates have been reported to inhibit various bacteria. In the current study, four food-grade polyphosphates were evaluated for their effects on the growth of Aeromonas hydrophila K144 in both a model system and a food system. Since polyphosphates can interact with other food factors, effect of these compounds were studied at different NaCl levels and temperatures. The model system was BHI Broth modified by the addition of polyphosphates (sodium pyrophosphate, sodium tripolyphosphate, Hexaphos, or Sodaphos) and NaCl; incubation was aerobic at 5 or 28C. The food system was ground pork with NaCl and polyphosphate added and inoculated with A. hydrophila. Individually, the polyphosphates were relatively noninhibitory in both BHI broth and ground pork, but NaCl and temperature interacted with the polyphosphates in the model system to increase generation and lag times of A. hydrophila. In BHI broth, a combination of 2% of any of the polyphosphates tested and 3.5% NaCl inactivated the bacterium; this inactivation was temperature-dependent. By both a plating system and electron microscopy, the polyphosphate-NaCl combination was shown to injure the bacterium. In the ground pork, the polyphosphate-NaCl combination limited growth of the bacterium during refrigerated storage. These results suggest that polyphosphates could be useful to control the presence of A. hydrophila in certain foods .