Determinação de Cianeto em sementes de Curcubita Moschata, cruas e tostadas, comercializadas em Natal/RN por espectrofotometria de absorção molecular

Abstract

Pumpkin seeds contains beneficial nutrients such as fiber, lipids and proteins. However, the seed also has cyanogenic glycosides, harmful to health. The objective of the present study was to quantify and compare the cyanide concentration in raw and toasted pumpkin seeds (Curcubita moschata). Parts of the seeds were purchased in supermarkets in Natal/RN, totaling five samples, and then the raw and toasted seeds were used. Total cyanide was measured by colorimetric method using alkaline picrate after acid hydrolysis of each sample. The cyanide values found ranged from 39.73 to 288.23 µg/g. According to the results it was possible to establish that among the raw or toasted seeds, the raw one obtained the highest concentration. Comparing the values between the ten samples, it was possible to suggest that the variation of cyanide content may be due to oscillations of several parameters during planting, harvesting and/or storage. Vegetables or fractions containing cyanide contents above 100 µg/g are considered toxic. Therefore, the samples analyzed in the current study can be classified as toxic. Considering that the tolerated daily dose established for foods containing cyanogenic glycosides is 90 μg cyanide / kg body, both raw and toasted samples are viable for daily consumption. Thus, up to 18.75 g of the highest cyanide raw sample and up to 33.5 g of the highest cyanide roasted sample can be consumed daily, following the tolerated daily dose of cyanide described above. These amounts would be close to two or three full tablespoons of seeds, recommending a controlled daily intake.