V. T. Maciel

Physicochemical composition, color and sensory acceptance of low-fat cupuaçu and açaí nectar: characterization and changes during storage

This study aimed to evaluate the physicochemical composition, color and sensory acceptance of low-fat acai and cupuacu nectar, as well as changes in these parameters during storage. Nectars were prepared with acai pulp previously defatted by centrifugation on a pilot scale. The study consisted of two steps. In the first step, the physicochemical characteristics, instrumental color, and sensory acceptance of the nectar prepared with low-fat acai pulp were evaluated and compared with those of nectar prepared with full-fat acai pulp. In the second step, titratable acidity, pH, soluble solids, anthocyanin content, instrumental color, and sensory acceptance of the low-fat acai and cupuacu nectar were evaluated for 6 months of storage at 25°C in the absence of light. The use of low-fat acai pulp resulted in nectars with good overall acceptance, but with lower scores for color acceptance than those of the full-fat nectar. The low-fat nectar remained stable with respect to acidity, pH, and soluble solid content during storage for up to 180 days. However, there was degradation of anthocyanins, which had a negative impact on the product color and sensory acceptance over time. Under the conditions evaluated, the estimated product shelf life is up to 120 days.

Quality of Brazil nuts stored in forced aeration silos

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

The natural drying of in-shell Brazil nuts carried out by the extractivists is not effective in reducing contamination by aflatoxin-producing fungi. Thus the use of an artificial heater could prove to be a favourable method to bring about a rapid reduction in the moisture content of the nuts and thereby prevent fungal growth. Hence the objective of this study was to evaluate the efficiency of a natural convection-type drier with respect to the physical, physicochemical and microbiological quality of nuts after drying for 6 hours at 45 °C. A random block experimental design with two treatments (nuts before and after drying) was used, using 10 replications of 3 kg. The nuts were analysed for their moisture, ash, protein, dietary fibre, total carbohydrates and lipid contents, water activity, total count of filamentous, potentially aflatoxin-producing fungi, and also the quantification of aflatoxins B1, B2, G1, G2 and the total aflatoxins. There was no effect of drying on the Aspergillus flavus and Aspergillus parasiticus counts or on the physicochemical composition of the nuts, except for the ash content. However the moisture content of the nuts was reduced by 39.7% and there was a decrease in the contamination by pre-existing total filamentous fungi. The dryer was effective in reducing the average time taken for drying as compared to the traditional method used by extractivists.