Effect of pentosans addition on pasting properties of flours of eight hard white spring wheat cultivars.

The effects of water extractable pentosans (WEP) and water unextractable pentosans (WUP) on pasting properties in flours of eight different hard white spring wheat (HWSW) cultivars was studied. WEP and WUP isolated from a hard wheat flour were added to each of the cultivars at 1% and 2% level. The results indicated that WEP exhibited a pronounced effect on pasting properties as compared to WUP and variety. Univariate analysis of variance (ANOVA) was used to evaluate sources of variation. The variety significantly (P < 0.001) influenced all the pasting parameters. WUP caused significant (P < 0.001) variation in paste viscosities (except breakdown). WEP influenced more pronouncedly the hot paste, cold paste, breakdown and setback viscosities with F values-221.802, 214.286, 98.073 and 120.159, respectively. Variety-by-WEP interaction exhibited significant (P < 0.01) influence on pasting time, peak, hot paste and cold paste viscosities. Whereas, variety-by-WUP interaction only significantly (P < 0.001) influenced the pasting- time and -temperature. Duncan's test was used to analyze the significant difference (P < 0.05) within the variety. The results revealed that WUP did not induce significant (P < 0.05) influence on all the pasting parameters, whereas, WEP influenced significantly (P < 0.05) the paste viscosities of some of the varieties. It was also found that the addition of WEP remarkably reduced the setback, hot paste, cold paste viscosities and increased the breakdown viscosity in all cultivar flours. The effect of WEP was greater at higher level of supplementation on paste viscosities.

Extraction, cleanup, and chromatographic determination of imidacloprid residues in wheat.

This study presents an improved method for quantitative analysis of imidacloprid residues in wheat grain using high performance liquid chromatography. The study used chromatographic response (in terms of peak height) as a quantitative tool for determination instead of peak area. The peak height of imidacloprid showed a very good linear correlation (R(2) = 0.999) when compared with absolute values at six different concentrations. The limit of detection was found to be 0.01 µg/mL. The recovery of imidacloprid residues in spiked wheat grain at three levels (0.03, 0.05, and 0.1 µg/g) was in the range of 79%-88% with %RSD 5.72 at 0.05 µg/g (w/w) and between 87% and 93% with %RSD 3.55 at 0.1 µg/g (w/w). At 0.03 µg/g (w/w) level, recovery was not within the recommended range of 70%-110%. Therefore, the lowest limit of quantification for this method was found to be 0.05 µg/g.

Determination of pesticide residues in rice grain by solvent extraction, column cleanup, and gas chromatography-electron capture detection.

A simple, easy, cheap and efficient analytical method for determination of multiple pesticide residues including organochlorine, organophosphorus, synthetic pyrethroids and herbicides in rice grain by capillary gas chromatography is developed. The quantification of residues was done by capillary gas chromatography with a µ-ECD detector and a HP-5MS capillary column. Known amounts of a mixture of pesticides were added to grain prior to extraction, cleanup and GC-determination. Recoveries were checked at two fortification levels; 0.1 and 0.5 µg/g. Qualitative and quantitative analysis were carried out based on the retention time and peak area basis. The results show that the average recovery of the analytical method for the fortified rice samples was in the range of 74%-111% and %RSD in the range of 2.41-12.42. The analytical method was used to analyze commercial rice grain samples.

Moisture content and its impact on aflatoxin levels in ready-to-use red chillies.

Moisture content (MC) and aflatoxin contamination were analysed to determine Red Chilli quality. A wide range (9.1-19.8%) of MC with a mean value of 11.4 ± 2.4% was found. Of 116 chilli samples, about 37% had low MC (<10%), 29.4% had medium-low MC (10-12%), 18.9% had medium-high MC (12 < MC < 14%) and 14.7% were above 14%. These four chilli groups had average aflatoxin levels of 2.1 ± 1.1, 5.3 ± 4.2, 8.9 ± 5.9 and 37 ± 20 µg/Kg, respectively. A direct relationship between moisture and aflatoxin content was found. The data best fitted a polynomial trend (R² = 0.89). The obtained equation could be utilised to assess aflatoxin levels based on MC. This study highlights the importance of using properly dried chillies with low MC, that is, ≤10%, to minimise health hazards associated with aflatoxin contamination.