Quality of Brazil nuts stored in forced aeration silos

Abstract

The traditional system of collection and storage of Brazil nut compromises seriously the quality of these almonds as it contributes to the high incidence of contaminants, like fungi of the genus Aspergillus, which can produce aflatoxins. In this study, the objective was to evaluate the influence of the storage period in studied conditions, on the physicochemical characteristics and on the microbiological contamination of Brazil nuts. The experimental was designed as completely randomized, considering as treatments the storage period (0 - control, 30, 60, 90, 120 and 150 days) with four replicates of 3 kg of Brazil nuts each. The samples were submitted to physicochemical and microbiological analysis. It was observed that almonds submitted to the storage had their moisture content reduced by 78.2% at 150 days of storage, however, this reduction was not fast enough to avoid surface contamination by filamentous and potentially aflatoxins producing fungi. The critical period of contamination occurred on the first 30 days of storage when there was an increase of the studied fungi, as well as B1 and total aflatoxin. The studied storage conditions were four times more effective in reducing the product moisture content than the traditional methods, however, pre-drying is necessary to avoid contamination of the product.

Quality of in-shell Brazil nuts after drying using a pilot natural convection oven in the state of Acre, Brazil

“…Santos et al (2011), for example, analysing processed Brazil nuts, packed in laminated flexible packs and in cardboard boxes, found low water activity (0.47) in the samples, which is an unfavourable condition for the growth of microorganisms. Costa et al (2016) in studies with in-shell Brazil nuts stored in a forced aeration silo, found that the water activity observed was below 0.70 after nearly 90 days of storage.…”

“…Quality of in-shell Brazil nuts after drying using a pilot natural convection oven in the state of Acre, Brazil Costa, D. A. et al of practice recommends that nuts should be dried to a safe moisture level (water activity below 0.70) (CAC, 2010) within 10 days after collection from the forest, after the removal of damaged, rotten, empty and rancid nuts (STDF, 2008). However, although a low water activity is obtained just after processing (SANTOS et al, 2011) or after storage with in-shell Brazil nuts under forced ventilation (COSTA et al, 2016), this is not yet the case for the traditional pre-drying carried out in extractivist communities, which endorses the observation that Brazil nuts should preferably not be stored within the communities. Santos et al (2011), for example, analysing processed Brazil nuts, packed in laminated flexible packs and in cardboard boxes, found low water activity (0.47) in the samples, which is an unfavourable condition for the growth of microorganisms.…”