Document Type : Research Paper

Authors

• Ali Ghasemi Chahardehi ¹
• Ghasem Asadpour ²
• Sead Majid zabihzadeh ³
• Esmaeil Rasooly Garmaroody ⁴

¹ Ph.D. Student of Cellulose industries, Agricultural Sciences and Natural Resources of Sari University. Iran

² Associate Professor, Department of Wood and Paper, Faculty of Natural Resources, Sari University of Agricultural Sciences and Natural Resources, Iran

³ Associate Professor, Department of Wood and cellulose products. Faculty of Natural Resources, Sari University of Agricultural Sciences and Natural resources, Iran

⁴ Assistant professor, Faculty of New Technologies, Shahid Beheshti University, Iran

Abstract

Background and purpose: The annual amount of food waste includes about one third of the global production of edible food. One of the main causes of meat waste is the disease caused by microorganisms. Using continuous and real-time tracking of food spoilage, waste can be significantly reduced. One of the main ways to identify the change in the quality of the food inside the package is the change in pH. by employing natural polymers containing pH-sensitive substances, it is possible to know the condition of the meat inside the package. Anthocyanins are natural substances sensitive to pH. This research investigated the use of eggplant peel extract to make a pH-sensitive Nanocellulosic biofilm as an indicator of meat spoilage inside the package.
Materials and methods: Eggplant peel, after crushing and passing through a sieve, was subjected to extraction in two separate methods (with and without formic acid). The amount of anthocyanin in each method was investigated and then the appropriate extraction method was selected based on the amount of anthocyanin obtained. The resulting anthocyanin, as the main substance sensitive to pH changes, was used in different percentages until the desired result was reached, to make nanocellulose film. In the production of nanocellulose film, anthocyanin was stabilized with the help of two types of cross-linking polymers, namely Penta sodium triphosphate and polyvinyl alcohol, in two separate paths, inside the nanofibrocellulose film, by casting method, at a temperature of 38̊Ϲ for 72 hours in an oven. The resulting film, as an indicator of meat spoilage, was placed inside the packaging of meat products. Some of the mentioned packages were kept at room temperature for three days and some others were kept in the refrigerator for seven days. The change in color of the films was evident in both cases, which indicated the microbial contamination of the meat.
Result: The results showed that the amount of anthocyanin in the extraction method with formic acid is twice that of the extraction method without it. The L a b test related to Nanocellulosic films showed that the b factor increased three and a half times in the films inside the package after spoilage the meat. Examination of the films with XRD showed that the addition of the binding polymer as well as the extract increases the degree of crystallinity of the nanocellulose film. Also, the results of FTIR showed that by adding binding polymers, new functional groups are created in the nanocellulose film, before and after being placed inside the packaging.
Conclusion: In this research, eggplant peel extract was used to make pH-sensitive nanocellulose film. In terms of anthocyanin content, the method with formic acid was superior to the method without it. Nanocellulose film, in the vicinity of rotten meat, changed color and became greenish yellow. The results show an increase in the degree of crystallinity due to the interaction between the components of the film. The extract itself also turned red in acidic pH and greenish-brown in alkaline pH. Finally, it was found that by using the visible color change of the aforementioned biodegradable nanocellulose film, it is possible to visually know the condition of the food inside the package.

Keywords

• Nanocellulose
• anthocyanin
• eggplant peel
• meat spoilage indicator and pH

Main Subjects

• Chemical conversion