Health Risk Assessment Of Nano-titanium Dioxide In Food

Titanium dioxide can be widely added to foods as food whitening additives.Some titanium dioxide particles in food additives exist in nanometer form.Compared with conventional scale titanium dioxide,nanometer titanium dioxide has more advantages in food application,such as slippery taste,high refractive index,strong covering rate,good whiteness.Nanomaterials may have certain effects on human health as its unique properties,such as surface effects and small size effects.Therefore,it is necessary to carry out health risk assessment of nano-titanium dioxide in food.Chewing gum with higher content of titanium dioxide was used as samples to separate titanium dioxide particles and the parameters such as morphology,particle size distribution,agglomeration state,chemical composition,crystal form,titanium dioxide content and nano titanium dioxide content were characterized.The characterization results were used for the exposure calculation of nano titanium dioxide.Combined with the hazard assessment of nano-titanium dioxide,the risk characterization of nano-titanium dioxide in food was carried out.Research indicates:（1）The presence of nano-sized titanium dioxide particles can be clearly observed by transmission electron microscopy.EDS analysis confirmed the existence of Ti and O elements in the samples,and some samples contained Mg,Al and Si elements.The percentage of nano-titanium dioxide in total titanium dioxide particles in Gum-1^Gum-6 ranged from 27.92%to49.58%,with an average of 41.25%.XRD characterization showed that most titanium dioxide particles were anatase type,and a few samples contained some rutile type titanium dioxide.The content of titanium dioxide in the samples determined by ICP-AES showd that the content of titanium dioxide in different brands of chewing gum varied greatly（1.15±0.11⁵.02±0.13mg/g）.Food-grade titanium dioxide accounted for 0.12%⁰.50%of the weight of chewing gum.The content of nano-titanium dioxide in chewing gum ranged from 0.14 to 0.62 mg/g,and the content of nano-titanium dioxide provided by each piece of chewing gum ranged from 0.20to 0.59 mg,and the amount of nano-titanium dioxide particles ranges from 0.63×10¹¹ to2.73×10¹¹.（2）The intake of nano-titanium dioxide for adults ranged from 0.26¹.16 mg/day（P50）and 1.12⁴.96 mg/day（P95）.When these values were quantified to the average body weight,the intake ranged from 4.29¹9.14μg/kg bw/day（P50）to 18.48⁸1.85μg/kg bw/day（P95）.The corresponding daily intake range of nano-titanium dioxide particles ranged from1.18×10¹¹⁵.11×10¹11 number/day（P50）to 5.04×10¹¹²1.84×10¹11 number/day（P95）.When these values were quantified to mean body weigh,from 1.94×10⁹⁸.42×10⁹ number/kg bw/day（P50）to 8.32×10⁹³6.04×10⁹ number/kg bw/day（P95）.（3）When the exposure of nano-titanium dioxide from chewing gum was 4.29×10^-3 mg/kg bw/day（P50）,the risk of nano-titanium dioxide on liver and spleen was small,but it can not be ruled out that nano-titanium dioxide has some effect on reproductive system.（4）In view of the percentage of nano-titanium dioxide in food（41.25%）and the fact that nano-titanium dioxide has certain risks to human health,it is suggested that risk avoidance can be achieved from food labeling,risk perception and product and liability traceability.It is of great significance to carry out health risk assessment of nano-titanium dioxide in food for the sustainable development of nanotechnology in the field of food and the protection of consumers’health.