Revestimento comestível para preservar a qualidade lipídica da castanha-do-brasil (Bertholletia excelsa)

Abstract

The Brazil nut, a valuable oilseed, plays an essential economic role for the Amazon rainforest region, primarily through its processing by extractive communities. Once harvested, these nuts are transported to cooperatives for further processing and sale. With a high fatty acid content of about 60%, Brazil nuts are highly prone to lipid oxidation, which affects their sensory qualities and shortens shelf life. This research aims to extend Brazil nuts' shelf life by creating an antioxidant edible coating that limits lipid oxidation. Eight different coating formulations were developed, with varying proportions of carboxymethylcellulose (CMC), sorbitol, nanocellulose (for added physical support), and a tocopherol-soy lecithin chemical barrier: C01 (CMC + sorbitol), CC1 (CMC + sorbitol + 1% nanocellulose), CC3 (CMC + sorbitol + 3% nanocellulose), CC5 (CMC + sorbitol + 5% nanocellulose), C02 (CMC + sorbitol + soy lecithin + tocopherol), CCT1 (CMC + sorbitol + soy lecithin + tocopherol + 1% nanocellulose), CCT3 (CMC + sorbitol + soy lecithin + tocopherol + 3% nanocellulose), CCT5 (CMC + sorbitol + soy lecithin + tocopherol + 5% nanocellulose). These coatings were evaluated in terms of physical characteristics like color, light and moisture barriers, mechanical strength, and biodegradability through edible films created via the casting method. Results indicated that all films were nearly fully biodegradable and showed promise for reducing petroleum-based plastic use. Among these, the CC5 and CCT5 formulations demonstrated superior mechanical resilience. Additionally, the nanocellulose-tocopherol blends in the CCT3 and CCT5 films provided stronger visible and UV light barriers, beneficial for enhancing nut preservation. Given their protective attributes, these films were applied as edible coatings; nuts coated with CC5 and CCT3 had the lowest peroxide values following accelerated oxidation tests at 60°C. Thus, CC5 and CCT3 coatings show significant potential to shield Brazil nuts from lipid oxidation, extending their shelf life effectively.