Tendency of lipid radical formation and volatiles in lose or vacuum-packed Brazil nuts stored at room temperature or under refrigeration

A G De O Sartori,L H Skibsted,M A.B Regitano D’Arce,D H.M Bastos,M H.F Spoto,G R Sampaio

doi:10.3989/gya.0114181

Abstract

The Brazil nut is an important product from the Amazonian region and its productive chain is an income source for local communities. The effect of combinations of packaging atmospheres (loose or vacuum-packed) and storage temperatures (4±1 °C or 24±2 °C) on the tendency of lipid radical formation and on volatiles was investigated for the first time in shelled Brazil nut kernels. It was observed that refrigeration, whether combined with lose packing or vacuum packing, was effective to reduce the tendency for lipid radical formation, as detected by spin-trapping electron spin resonance (ESR) spectroscopy, as well as peroxides, conjugated dienes and 3-octen-2-one. However, the combination of refrigeration with vacuum packing, even using low-density polyethylene (LDPE) pouches with a high oxygen transmission rate (OTR), also reduced the formation of hexanal, which is a major off-flavor volatile, and thus should be recommended for the storage of Brazil nut kernels for the studied period.

Highlights

Brazil nuts are the seeds of the Bertholletia excelsa Humb. & Bonpl. tree and originated in the Amazonian region
Portions of the kernels (300 g) were placed in low-density polyethylene (LDPE) pouches, which are commonly used as packaging material, vacuum or loose, for nuts in Brazil, with an estimated oxygen transmission rate (OTR) of 9843 cm3/m2/24h
Since the nuts were stored in the dark in the present study, these results suggest that trans-2-heptenal is majorly formed during the photooxidation (Lee and Min, 2010) of these nuts

Summary

Introduction

Brazil nuts are the seeds of the Bertholletia excelsa Humb. & Bonpl. tree (family of Lecythidaceae) and originated in the Amazonian region. Brazil nuts are the seeds of the Bertholletia excelsa Humb. Tree (family of Lecythidaceae) and originated in the Amazonian region. In Brazil, native people collect most of commercialized seeds as they fall from the trees in natural rainforests and no deforestation is needed (FAO, 2013). Global production of in-shell Brazil nuts has doubled in 25 years, from 49,740 tons in 1989 to 109,300 tons in 2014, and Brazil was the second largest producer, with an output of 39,000 tons in 2014 (FAO, 2017). The Brazil nut kernel is the greatest food source of selenium, which plays a key role as cofactor for antioxidant glutathione peroxidase (Rotruck et al, 1973). Selenium has antiviral effects, may be essential for human reproduction, and may reduce the risk of autoimmune thyroid disease (Rayman, 2012). Brazil nuts contain high contents of n-6 and n-9 fatty acids, vitamin E, magnesium, phosphorus, zinc, manganese, and sulphur-containing amino acids (USDA, 2015), besides bioactive compounds, such as phytoesterols (da Costa et al, 2010)

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