The Effect Of Processing And Preservation Methods On The Oxalate Levels Of Some Nigerian Leafy Vegetables

Titrimetric analysis was used to estimate the level of oxalate in some Nigerian leafy vegetables treated in different ways in two sets of experiments. The treatments were boiling with retention of the water used for boiling, and freezing followed by boiling without retention of the water used for boiling. Results obtained showed that the former in which five different vegetables were used led to significant increases (p<0.05) in the oxalate content of the vegetable preparations. The exception was Vernonia amygdalina in which there was a significant decrease in the oxalate content after boiling. The latter in which three selected vegetables were used however led to significant decrease (p<0.05) in the level of oxalate of the vegetable preparation, a significant amount having been lost in the decanted water. Boiling and then discarding the water used for boiling vegetables provides a good means of reducing the oxalate content of leafy vegetables and consequently the associated food safety problems

Natural multi-occurrence of mycotoxins in rice from Niger State, Nigeria

Twenty-one rice samples from field (ten), store (six) and market (five) from the traditional rice-growing areas of Niger State, Nigeria were analysed for aflatoxins (AFs), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisin B1 (FB1) and B2 (FB2), and patulin (PAT) by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) respectively. T-2 toxin was determined using TLC only. AFs were detected in all samples, at total AF concentrations of 28–372 μg/kg. OTA was found in 66.7% of the samples, also at high concentrations (134–341 μg/kg) that have to be considered as critical levels in aspects of nephrotoxicity. ZEA (53.4%), DON (23.8), FB1 (14.3%) and FB2 (4.8%) were also found in rice, although at relatively low levels. T-2 toxin was qualitatively detected by TLC in only one sample. Co-contamination with AFs, OTA, and ZEA was very common, and up to five mycotoxins were detected in a single sample. The high AF and OTA levels as found in rice in this study are regarded as unsafe, and multi-occurrences of mycotoxins in the rice samples with possible additive or synergistic toxic effects in consumers raise concern with respect to public health

The Effect Of Processing And Preservation Methods On The Oxalate Levels Of Some Nigerian Leafy Vegetables

Titrimetric analysis was used to estimate the level of oxalate in some Nigerian leafy vegetables treated in different ways in two sets of experiments. The treatments were boiling with retention of the water used for boiling, and freezing followed by boiling without retention of the water used for boiling. Results obtained showed that the former in which five different vegetables were used led to significant increases (p<0.05) in the oxalate content of the vegetable preparations. The exception was Vernonia amygdalina in which there was a significant decrease in the oxalate content after boiling. The latter in which three selected vegetables were used however led to significant decrease (p<0.05) in the level of oxalate of the vegetable preparation, a significant amount having been lost in the decanted water. Boiling and then discarding the water used for boiling vegetables provides a good means of reducing the oxalate content of leafy vegetables and consequently the associated food safety problems