食品添加剂明胶中二氧化硫含量测定的不确定度评定

对食品添加剂明胶中二氧化硫含量测定的不确定度进行评定。依据GB 6783-2013《食品添加剂明胶》对明胶进行二氧化硫含量的测定,依据JJF1059.1-2012《测量不确定度评定与表示》建立数学模型,分析不确定度的来源,根据来源的不同分类进行各类不确定度的评定和合成。结果表明,该研究中明胶中的二氧化硫含量为(10.84±0.22)mg/kg(95%置信概率,k=2)。测量结果的不确定度主要来源于滴定体积、重复性测定、氢氧化钠标准溶液的标定。     

食品添加剂用明胶的新旧标准主要差异

《食品安全国家标准食品添加剂明胶》(GB 6783-2013)将于2014年6月1日起实施,实施了20年的《食品添加剂明胶》(GB 6783-1994)将被代替,为了更好衔接新旧标准,将新标准与旧标准进行了比较,发现新旧标准发生较大的变化,新标准更加科学、合理和适用,并提出标准实施中一些建议。     

广州市售食品总铬和六价铬的含量分析

测定广州常见市售食品中添加明胶食品中的总铬和六价铬含量,评价这类食品铬污染情况。市区大型超市及肉菜市场购得5类食品,通过微波消解法和超声提取法对样品进行前处理,采用原子吸收分光光度计石墨炉法测定总铬和六价铬含量,根据《食品中污染物限量》进行评价。选择的五大类食品总铬含量超标率为达到41.67%,有牛肉丸、猪肉丸,果酱、酸奶和半固体汤料,其中牛肉丸、猪肉丸六价铬含量超过1 mg/kg。广州市售含明胶类食品的铬超标严重,应该加强其检测与监控,确保人们的饮食安全。     

厦门市市售土笋冻中铬的污染状况及来源探讨

目的了解厦门市市售土笋冻中铬的污染状况,探讨土笋冻中铬的污染来源及预防措施。方法 2012—2014年在厦门市各采样点随机抽取土笋冻样品81份,虫体样品9份,从宁德地区滩涂海域采集可口革囊星虫、淤泥、海水等环境样品6份,依照GB/T 5009.123—2003《食品中铬的测定》中推荐的石墨炉原子吸收光谱法测定样品中铬的含量。结果 81份土笋冻样品中铬含量范围在0.024~17.6 mg/kg之间,平均值为2.17 mg/kg,中位数为1.33 mg/kg,超标率为42.0%(34/81)。添加明胶加工后导致土笋冻中铬含量从1.33 mg/kg升至5.35 mg/kg。从宁德地区滩涂海域采集的星虫、淤泥、海水样品中铬的含量范围分别为2.67~2.70、68.5~77.9和0.038~0.046 mg/kg。结论厦门市市售土笋冻样品中铬的污染情况较为严重,监管部门须加强对土笋冻的原料、加工、销售过程的监控,保证食品安全。     

潮州市食用明胶产品中铬含量的调查结果分析

对辖区内食用明胶销售摊点或企业进行摸底排查,了解食用明胶产品中的铬含量,为使用明胶作为原料的食品进行风险监测研究奠定基础.采用原子吸收光谱法对食用明胶进行样品预处理和含量测定.方法的线性良好,在线性范围0 mg/L～0.500 mg/L内,相关系数达0.999 6;测试样品的RSD值为1.32％～8.34％;回收率为8...     

石墨炉法测定食用明胶铬时三种前处理的比较

为找到适合原子吸收光谱法测定食用明胶铬含量的前处理方法,对干式消解法、微波消解法和湿式消解法进行对比。结果发现,干式消解法使得明胶标准物质(铬含量1.5±0.15 mg/kg)中的铬有较大的损失,测定结果仅为0.91 mg/kg,测定结果需用回收率进行校正;微波消解法和湿式消解法的测定结果分别为1.40和1.61 mg/kg,方法检出限分别为0.08和0.12 mg/kg,精密度(n=7)分别为3.3%和2.2%,结果准确可靠。在使用GB 5009.123—2014原子吸收石墨炉法测定食用明胶中的铬时,应优先采用微波消解和湿式消解的样品前处理方法。     

食用明胶安全性介绍(一)

1.我国对食品添加剂明胶生产及使用的管理明胶是我国允许使用的食品添加剂,主要功能为增稠剂。作为食品添加剂使用的明胶,必须符合《食品添加剂明胶》(GB6783)规定质量规格要求。按照该标准规定,作为食品添加剂的明     

分光光度法测定不同食品基质中亚硝酸盐含量

目的建立测定不同食品基质中亚硝酸盐含量的分光光度法。方法取适量样品,按不同基质进行提取和净化,用分光光度法测定亚硝酸盐含量(以亚硝酸钠计)。结果方法检出限:液态乳和发酵乳中为0.02 mg/kg,其他样品中为0.2 mg/kg。淀粉类样品在添加浓度1.0~5.0 mg/kg范围内,回收率为77.6%~113%,RSD为1.9%~13.4%;肉制品类样品在添加浓度2.0~10.0 mg/kg范围内,回收率为77.5%~111.5%,RSD为2.1%~7.8%;腌菜类样品在添加浓度2.0~10.0 mg/kg范围内,回收率为58.5%~78.1%,RSD为4.0%~12.5%;液态乳、发酵乳类样品在添加浓度0.2~1.0 mg/kg范围内,回收率为81.5%~98.8%,RSD为1.4%~8.1%。结论该方法对不同食品基质样品的前处理方法进行了优化,干扰少,准确度、灵敏度高,能满足各类食品中亚硝酸盐的测定。     

2010年281份面制食品和淀粉类食品中铝残留量调查

目的了解市售面制食品和淀粉类食品中铝残留状况。方法采集吉林省长春市、吉林市、白城市、通化市、延吉市、四平市的食品商场、餐馆、集体食堂、集贸市场、早点摊位共281个食品加工点生产并销售的馒头、湿粉皮、粉条粉丝等样品,按GB/T 5009.182—2003《面制食品中铝的测定》方法检测,按GB 2762—2005《食品中污染物限量》进行评价。结果检测的72份油条样品,铝检出率为98.6%,超标率为54.2%,最高检出值超过限量值的2倍;80份馒头样品,铝检出率为40.0%,超标率为10.0%,最高检出值为183.5 mg/kg;64份湿粉皮中铝检出率为43.8%,铝含量超过100 mg/kg的样品为16份,最高检出值为342.3 mg/kg;65份粉条粉丝样品,铝检出率为52.3%,铝含量超过100 mg/kg的样品为10份,最高检出值为179.6 mg/kg。结论油条、馒头、湿粉皮、粉条粉丝中铝残留问题值得关注。     

郑州市淀粉制品中铝残留量调查

目的了解淀粉制品中铝含量的基础水平,为制定淀粉制品的铝限量标准和加强淀粉制品的安全监督提供依据。方法 2014年采集郑州及其周边县市的大中型连锁超市、居民区菜店、大型批发市场、农贸市场等所销售的保质期内的粉条、粉丝等定型包装和散装淀粉制品共256份,按GB/T 5009.182—2003《面制食品中铝的测定》方法检测,按GB 2760—2011《食品安全国家标准食品添加剂使用标准》进行判定,并以GB 2762—2005《食品安全国家标准食品中污染物限量》所规定的面制品(干重)中铝含量不超过100 mg/kg作为参考标准。结果 60份粉丝样品中,铝检出率为66.67%,含量范围ND~267.50 mg/kg,铝含量均值为27.16 mg/kg,中位数为16.40 mg/kg;114份粉条样品中,铝检出率达到92.11%,含量范围ND~696.30 mg/kg,最高检出值超过参考限量值约6倍,铝含量均值为171.36 mg/kg,中位数为123.50 mg/kg;12份粉皮样品的铝检出率为75.00%,含量范围ND~1 041.80 mg/kg,均值为113.95 mg/kg,中位数为22.55 mg/kg;10份焖子样品的铝检出率为100.00%,含量范围46.10~235.20 mg/kg,均值为96.88 mg/kg,中位数为69.95 mg/kg;60份凉粉、拉皮样品的铝检出率为90.00%,含量范围ND~393.70 mg/kg,最高检出值超过限量值约3倍,样品均值为57.62 mg/kg,中位数为46.65 mg/kg。结论部分淀粉制品中的铝残留量较高,主要与使用含铝食品添加剂有关,应加强含铝食品添加剂的监管。     

阿胶类保健食品中阿胶成分和牛皮源成分检测及质量评价

采用超高效液相色谱-串联质谱法对6种类型、共计67批阿胶类保健食品中阿胶成分和牛皮源成分同时进行测定,结合阿胶含量、水分、蛋白质含量的测定结果对每种剂型中阿胶成分和牛皮源成分进行分析与评价,对日后专项标准制定和监管方向提出建议。结果表明:阿胶片中阿胶含量较高,为39%～65%,蛋白质含量也较高,为68%～84%,牛皮源成分的检出率为22. 8%,检出且超过标准规定的有2批;阿胶粉、阿胶胶囊、阿胶含片、阿胶核桃糕和阿胶口服液中,以4种氨基酸代表的阿胶含量差异较大,与阿胶片相比数值较低,检出牛皮源成分的有16批,但均未超过标准规定。超高效液相色谱-串联质谱法可以同时快速、准确地对阿胶成分特征峰和牛皮源成分特征峰进行判别;加强阿胶类保健食品的原材料监管、并按类型区别制定阿胶类保健食品中牛皮源掺入限值标准十分必要。     

花生蛋白质凝胶食品的生产工艺研究

研究了以花生仁为原料,用氯化钙作为凝固剂的花生蛋白质凝胶食品的生产工艺,并对影响花生蛋白质胶凝性的各因素进行实验研究,得出它们与成品之间的关系,并通过正交实验确定制作产品的最佳工艺条件。花生浆浓度为1∶6,凝固剂添加量为每200mL花生浆使用5%的氯化钙溶液6mL,点浆温度为85℃,pH为6,制作的花生蛋白食品凝固状态好,有弹性,质地细腻,颜色为乳白色,口感细嫩,有典型的花生香气。     

Photoactivated chlorophyllin-based gelatin films and coatings to prevent microbial contamination of food products

The aim of this work was to develop antimicrobial photosensitizer-containing edible films and coatings based on gelatin as the polymer matrix, incorporating sodium magnesium chlorophyllin (E-140) and sodium copper chlorophyllin (E-141). Chlorophyllins were incorporated into the gelatin film-forming solution and the inhibiting effect of the cast films was tested against Staphylococcus aureus and Listeria monocytogenes. The results demonstrated that water soluble sodium magnesium chlorophyllin and water soluble sodium copper chlorophyllin reduced the growth of S. aureus and L. monocytogenes by 5 log and 4 log respectively. Subsequently, the activity of self-standing films and coatings containing E-140 was assessed on cooked frankfurters inoculated with S. aureus and L. monocytogenes. These tests showed that it was possible to reduce microorganism growth in cooked frankfurters inoculated with S. aureus and L. monocytogenes by covering them with sodium magnesium chlorophyllin-gelatin films and coatings.     

Analytical methods for gelatin differentiation from bovine and porcine origins and food products

Usage of gelatin in food products has been widely debated for several years, which is about the source of gelatin that has been used, religion, and health. As an impact, various analytical methods have been introduced and developed to differentiate gelatin whether it is made from porcine or bovine sources. The analytical methods comprise a diverse range of equipment and techniques including spectroscopy, chemical precipitation, chromatography, and immunochemical. Each technique can differentiate gelatins for certain extent with advantages and limitations. This review is focused on overview of the analytical methods available for differentiation of bovine and porcine gelatin and gelatin in food products so that new method development can be established.     

不同来源明胶软糖质构的研究

采用质构分析的方法,研究了明胶添加量、不同来源的明胶和明胶与琼脂复配对明胶软糖质构的影响。结果表明,明胶软糖的硬度随明胶的添加量增加而增大、咀嚼性变强,明胶添加量为6%时黏性最小。不同来源的明胶影响明胶软糖的感官特性,其中猪皮来源的明胶软糖硬度大、咀嚼性强;鱼鳞来源的明胶软糖硬度小、咀嚼性弱、热稳定性差、黏性大;牛皮和牛骨来源的明胶软糖硬度和咀嚼性适中。在明胶软糖中添加琼脂可以降低软糖黏性、提高热稳定性。当琼脂添加量为0.8%时,明胶软糖的弹性最好、软硬适中。综合考虑,生产具有高热稳定性和良好感官品质的明胶软糖选用牛皮或猪皮来源、6%明胶与0.8%琼脂复配较为合适。     

Encapsulation of curcumin in electrosprayed gelatin microspheres enhances its bioaccessibility and widens its uses in food applications

Curcumin has uses as a food colorant and functional ingredient, these uses being restrained owing to its low solubility in water, which limits its dispersion in food matrices and its bioaccessibility. Curcumin–gelatin microparticles produced by electrohydrodynamic atomization were developed to overcome these problems. Microparticles with a size up to 1.2 μm in diameter, in which curcumin was in the amorphous state, were obtained. Both curcumin water solubility and bioaccessibility were significantly improved by encapsulation (38.6 and 11.3-fold higher than commercial curcumin, respectively). A gellified fish product was used to evaluate the coloring capacity of microencapsulated curcumin, finding a better dispersion for microencapsulated curcumin than for commercial one. However, curcumin bioaccessibility was similar owing to curcumin solubilization into the protein matrix. In spite of this, a protective effect of curcumin was observed, as the antioxidant activity of the bioaccessible fraction of the gel supplemented with microencapsulated curcumin was higher.Industrial relevanceCurcumin is a potential natural food coloring and functional ingredient which impairs an attractive yellowish-orange color to food and possesses a wide range of biological activities. However its use in food is restrained owing to its low solubility in water. Curcumin encapsulation using a soluble polymer is a promising strategy to widen the use of curcumin as an ingredient in the food industry.     

玉米凝胶淀粉

<正> 近来,由于饮料及冷冻食品不断发展,对于胶凝剂、增稠稳定剂的需求不断上升,常用的胶质类胶凝剂明胶等来源有限,加工工艺繁琐,价格昂贵。 淀粉虽有增稠作用,但不具有或仅有很低的凝胶性能。将淀粉改性得到的凝胶淀粉,具有热糊、冷糊稳定性、较强的凝胶强度和冻融稳定性,价格便宜,仅是明胶的1/5。 试验以玉米凝胶淀粉替代明胶作果冻胶凝剂、冰淇淋稳定剂,并试验作发酵乳、粒粒橙等饮料的增稠稳定剂,研究其实际应用性能。     

Phase separation in gelatin/dextran and gelatin/maltodextrin mixtures

Phase separation mechanisms and kinetics in quiescent and shear conditions were studied using small-angle light scattering, optical polarimetry and confocal laser scanning microscopy in the gelatin/maltodextrin and gelatin/dextran systems. In the former system the temperature quench caused phase separation, which was studied in the gelled and liquid states, whereas in the latter system phase separation was triggered by the conformational ordering of the gelatin molecules and could only be studied when the system gelled. In both systems the different phase separation mechanisms of nucleation and growth and spinodal decomposition were identified from the different behaviour of structure function measured by light scattering. In the liquid state coarsening of the microstructure occurred by droplet coalescence that was accelerated by hydrodynamic effects when the droplets reached a certain size. Gelation hindered, but did not prevent coarsening. Reduced coarsening rates were measured in the gelled systems. In most cases the phase separation kinetics were faster than the gelation kinetics, and the system rapidly evolved into the late stages of phase separation that were characterised by a well-defined morphology with sharp interfaces. For sufficiently rapid ordering kinetics, corresponding to deep quenches, in the gelatin/dextran systems, however, it was possible to trap the microstructure in the early stages of phase separation while the interfaces were still diffuse. When the phase-separated liquid gelatin/maltodextrin system was sheared, coarsening was accelerated at low shear rates due to increased rates of droplet coalescence. At higher shear rates, stable elongated structures were formed. At one particular shear rate (approximately 1 s⁻¹), the rates of break-up and coalescence were balanced and a monodisperse size distribution of elongated droplets was formed.     

Thermal characterisation of gelatin extracted from yellowfin tuna skin and commercial mammalian gelatin

Glass transition and other thermal characteristics of gelatin from different sources were studied by differential scanning calorimetry (DSC) and modulated DSC (MDSC). The initial glass transition temperatures of equilibrated gelatin samples at 11.3% relative humidity, determined from reversible heat flow thermogram of MDSC, were 23, 75 and 59 °C, respectively, for tuna skin, bovine and porcine gelatin. When gelatin samples were equilibrated at higher relative humidity of 52.9%, glass transition temperature of fish skin and bovine gelatin decreased to −3 and 57 °C, respectively. Further increase of equilibration relative humidity to 75.3% showed increased value in the case of tuna skin, whereas bovine and porcine did not show any significant change. DSC and MDSC results indicated that tuna gelatin showed lower glass transition compared to mammalian source gelatin equilibrated at the same constant relative humidity. In general glass transition measured by DSC was found lower than the values measured by MDSC. The results in this study showed that the degree of plasticization varied with the source of gelatin as well as their extraction methods.