| Grain production and consumption of our country sustain a large proportion in world, therefore grain food safety is an important part of foodstuff safety to affect people’s daily life health and social stability and development. Recent food safety issues are increasing demand for traceability systems in all foodstuff to realize tracing and quality control effectively during the process from origin harvest to table. Identification technology is one of the key technologies in traceability, which enable to connect information chain with material chain with an data carrier, moreover, to realize a quick, accurate, efficient method for recognition product information and make sure robustness of identification in traceability system.During the process of grain production, it is very difficult to trace origin in bulk grains with identification technology like other agriculture products because of their small individual size and massive overall quantities. Moreover, grain from various origins is typically mixed with different usage and grade at multiple points in the supply chain, making point of origin impossible to determine. In order to realize a low cost, accurate method to tracing grain information in grain supply chain, it was proposed the method of food-grade tracers printed with two-dimensional Data Matrix bar code as grain information carriers. For each link in supply chain, food-grade grain tracer was mixed with grain to gain the connect of information chain with material chain, and tracing grain to origin at a low cost. Therefore, the mainly work had been accomplished as followed to develop an grain identification technology with the characteristic of uniqueness, precision and durability, in order to make sure the characteristic to be appropriate for grain production environment.(1) In order to avoid contamination of grain, this study used edible raw material powder, silicified microcrystalline cellulose and magnesium stearate to product the two types tracers of sugar-based and cellulose-based with direct compression method. The tracer dimensions were1lmm in length,6mm in width and4mm in thick. While the difference particle composition in types of tracers resulted in different particle density, so the weight of two types tracers were different. The resulting average weight was0.36g for sugar-based and0.29g for cellulose-based tracers.(2) The two-dimensional Data Matrix bar code was used in grain information encoding to accommodate more information. Based on tracer dimensions and the request of printing two-dimensional Data Matrix bar code on tracer surface, the code was designed to have an8*18format with module size of0.43×0.43mm2, which enabled one code symbol to fit on the surface of a tracer. The two-dimensional Data Matrix was printed with ink-jet printing technology and edible ink on tracer surface.(3) Three groups of Data Matrix bar code were printed on sugar-based and cellulose-based tracers to assess the readability of two types of tracers. The printing of DM codes on sugar-and cellulose-based tracer particles was found to be readily feasible, and the readability for both types was above90%(92.5%-98.0%), illustrating the good printability on the two types of tracers. Moreover, the readability of DM codes on cellulose-based tracers was better (95.5%to98.0%) than that on sugar-based tracers (92.5%to96.5%). The T-test indicated a significant difference in readability between sugar-and cellulose-based tracers (p<0.05).(4) The surface roughness of grain tracer affected the printing quality of Data Matrix bar code, it was researched on the measurement of grain tracer surface roughness to evaluated the effect of surface roughness on readability of Data Matrix bar code printed on tracers and to improve the printing quality. Surface roughness Ra and Rrms value was measured by3D profilometer. A scanning area was0.70x0.56mm2when image was collected with a10-X objective. The area of Data Matrix bar code on grain tracer was7.74X3.44mm2, therefore, it was needed to measure the average of several scanning area. A test was designed to assess3,5,8,10areas measurement average value as the sample surface roughness, the results implied that5area measurement on each sample can reflect the entire surface roughness approximately.(5) In order to study the effect of surface roughness on the readability of Data Matrix code, an experiment was designed to assess the effect of two types tracers surface roughness on readability of Data Matrix code printed on their surface. The results showed that the readability of cellulose-based tracer was higher than that of sugar-based tracer, at the same time, the surface roughness Ra and Rrms values were lower than that of sugar-based tracer. Overall, readability decreased with the roughness increasing. However, when the changing degree of roughness is very small, the readability was affected by adsorption between the ink and the material characteristics of the particle surface material.(6) A two-factor factorial design was employed to analyze the influence of different formation pressures and constituent formulations on surface roughness.The results were analyzed by fuzzy comprehensive evaluation method to determine the optimum combinations process parameters. The analysis results indicated that the optimal process parameters of sugar-based tracers was at the pressure of2.727MPa with the formula of99%sugar and1%stearic acid magnesium; the optimal process parameters of cellulose-based tracers was at the pressure of3.636MPa with the formula of36.5%sugar,62.5%silicified microcrystalline cellulose and1%stearic acid magnesium.(7) In the grain production supply chain with grain tracer as its information identification, the characteristic of ruggedness was needed to meet the require of abrasion resistance and impact resistance when mixing tracers with grain in supply chain, which enabled grain tracer to adapt to grain tracing environment. Fourteen treatments involving two tracer types (sugar-based and cellulose-based), two coating materials (edible shellac and hydroxypropyl methylcellulose), and four coat-print procedures were considered to assess the abrasion resistance and impact resistance in the conveying test and impact test. Grain tracers are expected to absorb some finite amount of moisture when mixed with grain and stored in a grain bin, therefore, the effect of moisture absorption by the tracers was assessed by conducting the ruggedness tests with dry and moist tracers. The results of the ruggedness experiment showed that the treatment performed very well in the conveying test and impact test both under moisture test and no moisture, which was cellulose-based tracer coated with hydroxypropyl methyl cellulose after printing.The above study is mainly around the information identification in supply chain of grain traceability system, and information acquisition system was needed to identify grain tracer. Taking paddy in storage as an example in this study, a tracing information acquisition system in storage was proposed based on wireless sensor network, which enable to gain the grain identification, temperature and humidity in bulk grain and grain moisture information. In order to realize this system, some problems were resolved in this paper. It was proposed the portable collection method of using two-dimensional the barcode scanner IT4800SR connected with S3C6410, which was instead of the traditional collection with PC.To achieve real-time acquisition of stored paddy moisture content, this paper presented a real-time monitoring program based on the principle of equilibrium moisture content. |
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