Recycling Citrus and Garlic Processing Wastes with Diverse Potential Applications

Abstract

Annually, the world generates more than 1.3 billion tons of food loss and food waste and produces more than 300 million tons of plastic, 50% of which are single-use. While most of the food waste generated across the globe is suitable for composting or use as animal feed, others like citrus and garlic-processing wastes have been denoted as challenging to the environment.

Citrus peels are rich in oils and highly acidic, making them unsuitable for animal feed or composting as they harm the soil and prolong the composting process. As for garlic stalks, not only are they hard to digest by animals due to high quantities of lignin, they also cause soil pollution and add waste problems.

This study investigates the possibility of recycling citrus and garlic processing waste into a bio-based and biodegradable material with the potential to replace plastics and other non-renewable materials.

This work aims to develop and characterize the envisioned material in terms of mechanical, thermal, sorption and migration properties to assess its potential applications and compare it to conventional materials in an attempt to reduce human-induced environmental stresses.

The accomplished material was proven highly heat resistant, mechanically strong, and moldable. When immersed in a natural waterproof coating based on beeswax, it resisted absorption of food simulants for 7 minutes, without migration of any natural additive from the material formulation into the food simulant media. Moreover, the developed material has a density and thermal conductivity close to building materials. Applying an optimized coating to the developed material expands its commercial applications ranging from disposable tableware, coasters, and placemats to tiles and building materials.