Recycled newspaper cellulose based colorimetric sensor of biogenic amines for food spoilage indication

Cellulose was extracted from newspaper waste and purified by alkali treatment process. The white color cellulose without ink and glue was obtained and then characterized by Fourier transform infrared spectroscopy and X-ray diffraction spectroscopy. Thermogravimetric analysis reported that the purified cellulose was thermally stable at the room temperature. The microstructure of cellulose showed random orientation of fiber with air-instituted in between, confirmed by scanning electron microscopy and laser confocal microscopy. The purified cellulose was applied as the substrate for enzymatic colorimetric sensor. The sensor was fabricated by immobilizing pH indicator and diamine oxidase on the cellulose surface. Then, the sensor responses toward the bogenic amines (cadaverine, putrescine and histamine), the food spoilage indicator, were measured by naked eye and spectrophotometry. The color change from orangish to a blueish color with linear range of 0.25–2.0 mg/mL for cadaverine, 0.05–2.0 mg/mL for putrescine, and 2.5–10.0 mg/mL for histamine, were obtained. This platform was advantageous due to ease of use, low cost, portable size, and user-friendly readout. Ultimately, this recycled newspaper based colorimetric biogenic amine sensor was applied for the detection of biogenic amines in ground pork samples with satisfactory results.