Design and fabrication of starch-nano clay composite films loaded with methyl orange and bromocresol green for determination of spoilage in milk package

In this work, new composite film based on starch and nano clay particles was provided. The nano composite film was loaded by methyl orange (MO) and bromocresol green (BG) indicators. Two type films, including starch-nano clay-methyl orange (SCMO) and starch-nano clay-bromocresol green (SCBG) were provided. Some properties of provided films, including solubility in water, moisture uptake, water vapor permeability, FT-IR, and scanning electron microscopy were studied. According to the results, MO and BG were loaded between starch and nano clay particles physically and clay particle size was between 40 and 100nm. Finally, the SCMO and SCBG simultaneously were improvised in the milk bottle. According to the color change of indicators in the different pH (MO [3.1-4.4] and BG [3.8-5.4]), the fabricated films were used for determination of milk spoilage in a milk bottle. The best advantage of fabricated SCMO and SCBG films is that the indicators do not release into the milk by exposing with the milk. The milk pH is changed during the storage time (from 6.7 to the 4), and in the low pH, the milk is spoiled so the fabricated film smartly could show the spoilage of milk by color changing.