Cereal sampling

To determine Ks we need to know the average mass of the cereal samples and the relative standard deviation for the %(w/w) ash. The average mass of the five cereal samples is 1.0007 g. The average %(w/w) ash and the absolute standard deviation are, respectively, 1.298% and 0.03194. The percent relative standard deviation, therefore, is... 

The ABC cereal company is developing a new type of breakfast cereal to compete with a rival product that they call Brand X. You are asked to compare the energy content of the two cereals to see if the new ABC product is lower in calories so you burn 1.00-g samples of the cereals in oxygen in a calorimeter with a heat capacity of 600. J-(°C). When the Brand X cereal sample burned, the temperature rose from 300.2 K to 309.0 K. When the ABC cereal sample burned, the temperature rose from 299.0 K to 307.5 K. (a) What is the heat output of each sample (b) One serving of each cereal is 30.0 g. How would you label the packages of the two cereals to indicate the fuel value per 30.0-g serving in joules in nutritional Calories (kilocalories) ... 

The cereal samples are milled with an ultracentrifuge mill and sieved through a 42-mesh screen, then 10 g of the sieved sample are transferred into a 300-mL Erlenmeyer flask and soaked in 30 mL of distilled water for 60 min. After 100 mL of acetone have been added, the procedure described for vegetables and fruits is followed. 

For n = 15 cereal samples from barley, maize, rye, triticale, and wheat, the nitrogen contents, y, have been determined by the Kjeldahl method values are between 0.92 and 2.15 mass% of dry sample. From the same samples near infrared (NIR) reflectance spectra have been measured in the range 1100 to 2298 nm in 2nm intervals each spectrum consists of 600 data points. NIR spectroscopy can be performed much easier and faster than wet-chemistry analyses therefore, a mathematical model that relates NIR data to the nitrogen content may be useful. Instead of the original absorbance data, the first derivative data have been used to derive a regression equation of the form... 

Klemsdal, S. S., and Elen, O. (2006). Development of a highly sensitive nested-PCR method using a single closed tube for detection of Fusarium culmorum in cereal samples. Lett. Appl. Microbiol. 42, 544—548. 

Knoll, A., Vogel, R. F., and Niessen, L. (2002). Identification of Fusarium graminearum in cereal samples by DNA Detection Test Strips . Lett. Appl. Microbiol. 34,144-148. 

Niessen, M. L., and Vogel, R. F. (1998). Group specific PCR-detection of potential trichothecene-producing Fusarium-spedes in pure cultures and cereal samples. Syst. Appl. Microbiol. 21, 618-631. 

Cereal sample (e.g., wheat, barley) or potato starch 3 1 (v/v) n-propanol/water mix well prior to use Deionized H20... 

Riboflavin (vitamin B2) is determined in a cereal sample by measuring its fluorescence intensity in 5% acetic acid solution. A calibration curve was prepared by measuring the fluorescence inteiisities of a series of standards of increasing concentrations. The following data were obtained. Use the method of least squares to obtain the best straight line for the calibration curve and to calculate flie concentration of riboflavin in the sample solution. The sample fluorescence intensity was 15.4. 

Contamination levels in the majority of raw cereal samples were below 5 pg/ kg. Owing to the very small number of samples contaminated above the highest proposed limit of 20 pg/kg for cereals, such an ML would have very limited impact compared with no ML. The Committee concluded that the use of an ML of 5 or 20 pg/kg would be unlikely to have an impact on dietary exposure to ochratoxin A. The Committee was unable to reach a conclusion regarding the situation in developing countries, owing to the lack of adequate data with which to do an assessment. 

Niessen ML, Vogel RE (1998) Group Specific PCR-Detection of Potential Trichothecene-Producing Fusarium Species in Pure Cultures and Cereal Samples. System Appl Microbiol 21 618... 

Figure 13.7 (a) Non-standardized vs (b) standardized TDS curves for texture evaluation of a breakfast cereal sample. 

Table 6.9. Heavy metals concentration in cereal samples in the fixed points situated in the sanitary protection zones (1989-93)...

Microwave extraction provided an efficient online method for the liberation of flavins from complex food matrices. Because of the acidic medium used and the microwave power, the conversion of flavins from one form into another occurred after liberation from the sample matrix and 100% conversion of FAD to FMN after extraction was observed. Some conversion of FMN into riboflavin was also observed (about 15.2%). This was taken into account when analyzing samples where the FMN content was determined by increasing the figure reported by 15%. For those products in which FMN was not detected no assumptions could be made. The method was compared with the AOAC fluorimetric method commonly applied for milk and cereal samples, with recoveries of 94-106% for spiked riboflavin. 

Precision obtained for the samples in Table 19.2, expressed as relative standard deviations (RSD), ranges from 0.5% to 2.7%. Mean levels of niacin obtained for the commercial flour and cereal samples are higher than the expected values, but this is not surprising. Due to labelling requirements for fortified foods (Bender et al. 1998), such foods are often fortified in excess of the stated amounts. Results for the flour (RM 8437) and cereal (RM25C) reference... 

Table 19.2 Results of niacin determinations for food samples. Niacin determinations by LC-IDMS are compared to expected values for six grain-derived food materials. Expected levels for the commercial flour and cereal samples (Brands A, B, C, and D) are according to the package labelling, although it should be noted that actual vitamin levels of vitamin fortified foods are often higher than the stated amounts. The determined niacin levels for these samples, listed in the third column with their 95% confidence limits, are from 30% to 70% higher than the claimed levels. Determined niacin levels for the two reference materials (RM) are in agreement with the expected levels. Data are from Goldschmidt and Wolf (2007), with permission from the publisher.

Tyler, T.A., and Shrago, R.R., 1980. Determination of niacin in cereal samples by HPLC. Journal of Liquid Chromatography. 3 269-277. 

Aqay et al. (2011) have described a method based on nano-LC-quadrupole time-of-flight-MS (nano-LC-QTOF-MS) for the screening of ochratoxins in wheat and cereal samples. The mycotoxin ochratoxin A (OTA) and cross-reacting mycotoxin analogues were analyzed in these samples after extraction using a novel direct inhibition flow cytometric immunoassay with superparamagnetic microbeads coated with monoclonal antibodies. The limit of detection (LOD) for OTA was 0.15 ng g", below the lowest... 

Asfaha DG, Quetel CR, Thomas F, Horacek M, Wimmer B, et al. Combining isotopic signatures of n( Sr)/n( Sr) and light stable elements (C, N, O, S) with multi-elemental profiling for the authentication of provenance of European cereal samples. J Cereal Sci 2011 53 170-7. 

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