A method for determining kernel moisture content and aflatoxin concentrations in peanuts

A method was developed to determine kernel moisture content (KMC) and aflatoxin concentration in discrete peanut samples. Shelled peanuts were weighed to the nearest 0.01 g, and a water slurry was made by blending the peanuts for 2 min with 2.2 ml of water per g of peanuts. The slurry (10 g) was withdrawn and dried at 130°C for 3 h to determine KMC. Methanol was added to the remaining slurry and blended for an additional 1 min, and aflatoxins were quantitated with high-performance liquid chromatography. Comparison of the slurry method with an official peanut moisture method showed good agreement between the two over a range of moisture levels. Recovery of aflatoxin B₁ from spiked samples averaged 97% with an average coefficient of variation of 3.6%. The method enables determination of both KMC and aflatoxin content in peanut samples without degradation of aflatoxin that would occur when using the official moisture method.     

Theoretical investigations into the accuracy of sampling shelled peanuts for aflatoxin

Within a population of shelled peanuts, aflatoxin may be concentrated in less than 0.5% of the peanuts. Those peanuts containing aflatoxin might have concentrations up to 1,000,000 μg of aflatoxin per kilogram of peanuts. Because of the distribution pattern, sample means vary widely, and the true average level of aflatoxin in the population is difficult to estimate. The objective of this study was to determine the effect of sample size, N, on sampling accuracy. The negative binomial distribution of aflatoxin since it allowed for a high probability of zero counts along with small probabilities of large counts. Using both the Monte Carlo technique and a direct computation method, the effect of sample size on sampling accuracy was quantitatively described. Journal Paper No. 2775, North Carolina State University Agricultural Experiment Station, Raleigh, N.C.     

A justification for using a whole-grain oven method to determine soybean moisture content

Three air-oven moisture methods, AOCS Ac 2-41, AACC 44-18 and the official USDA method, were compared on 20 samples of 1987 crop soybeans. The AOCS method is a whole-grain method, the other two are two-stage, ground-grain methods. The average difference between the AOCS and USDA methods was 0.04 percentage points with a standard deviation of 0.18 points. The AOCS method can be used interchangeably with the USDA method for calibration of moisture devices. The AACC method averaged 0.15 and 0.19 points higher than the AOCS and USDA methods, respectively.     

Comparison of the observed distribution of aflatoxin in shelled peanuts to the negative binomial distribution

Suitability of the negative binomial distribution for use in estimating the probabilities associated with sampling lots of shelled peanuts for aflatoxin analysis has been studied. Large samples, called “minilots,” were drawn from 29 lots of shelled peanuts contaminated with aflatoxin. These minilots were subdivided into ca. 12 lb samples which were analyzed for aflatoxin. The mean and variance of these aflatoxin determinations for each minilot were determined. The shape parameterk and the mean aflatoxin concentrationm were estimated for each minilot. A regression analysis indicated the functional relationship betweenk andm to be:k=(2.0866+2.3898m) × 10⁻⁶. The observed distribution of sample concentrations from each of the 29 minilots was compared to the negative binomial distribution by means of the Kolmogorov-Smirnov test. The null hypothesis that each of the true unknown distribution functions was negative binomial was not rejected at the 5% significance level for all 29 comparisons. Journal Series Paper of the North Carolina State University Agricultural Experiment Station, Raleigh, N.C.     

Information content of methods of determining coke reactivity

The reactivity of coke plays an important role in blast-furnace smelting. The reaction of carbon in coke with oxygen generates the heat required for various chemical reactions in the blast furnace. The reaction of carbon in coke with carbon dioxide and water vapor forms carbon monoxide and hydrogen, which reduce the iron and alloying elements from their oxides. As a result of these reactions, the strength of the coke pieces in the blast furnace is reduced, and they break down more as they move in the furnace batch, with consequent decrease in gas permeability of the batch column.     

A rapid method of determining the moisture content of hydrocellulose films and casings

Translated from Khimicheskie Volokna, No. 6, pp. 54–55, November–December, 1991.     

Design and analysis of sampling plans to estimate aflatoxin concentrations in shelled peanuts

Methodology for use in the design and evaluation of sampling plans to estimate aflatoxin concentrations in lots of shelled peanuts is presented. Use of the operating characteristic curve for comparing and evaluating processor and consumer risks related to various sampling plans and application of the negative binomial distribution to estimate probabilities associated with sampling lots of shelled peanuts for aflatoxin concentration are discussed. Operating characteristic curves are developed for two different single-sample plans, an attribute multiple sample plan, and the plan presently used by the peanut industry to estimate aflatoxin concentrations in commercial lots of shelled peanuts. An estimated prior distribution of lots according to aflatoxin concentration is used to predict, among others, such values as the per cent of all lots tested that will be accepted by the sampling plans and the average aflatoxin concentration in the accepted lots. All four of the sampling plans described in the paper are compared on the basis of values such as these. Other factors to be considered in the critical evaluation and selection of sampling plans for estimating aflatoxin concentrations in commercial lots of shelled peanuts are discussed. Paper number 3197 of the Journal of Series of the North Carolina State University Agricultural Experiment Station, Raleigh, N.C.     

Photometric and titrimetric methods of determining the gallium content in glasses

Translated from Steklo i Keramika, No. 6, pp. 29–30, June, 1993.     

确定煤气处理量时需要考虑的影响因素

根据理论分析及实际生产经验,提出了在设计中确定焦炉煤气处理量时需要考虑的主要影响因素。最终确定的煤气处理量应在保证煤气净化指标的前提下,综合考虑净化装置操作的经济性与稳定性。     

Rapid method for determining moisture content in crude palm oil by Fourier transform infrared spectroscopy

A simple, rapid, and direct Fourier transform infrared (FTIR) spectroscopic method was developed for the determination of moisture content of crude palm oil (CPO). The calibration set was prepared by adding double-distilled water to dried CPO in ratios (w/w) between 0 and 13% moisture. A partial least squares (PLS) regression technique was employed to construct a calibration model followed by cross-validation step. The accuracy of this method was comparable to the accuracy of the American Oil Chemists' Society's vacuum oven method, which is used for determination of moisture and volatile matter, with mean difference (MD_a) of 0.0105, a coefficient of determination (R ²) and a standard error of calibration (SEC) of 0.9781 and 0.91, respectively. It is also comparable to the accuracy of the International Union of Pure and Applied Chemistry's distillation method with MD_a, R ², and SEC of 0.0695, 0.9701, and 0.65, respectively. The study showed that midband FTIR spectroscopy combined with the PLS regression calibration technique is rapid and accurate for determination of moisture content of CPO samples with a total analysis time of less than 2 min and less than 2 mL of sample.     

A new mthod for determining oven aging stability of polypropylene monofilament

A precise method of oven-aging polypropylene monofilament has been developed employing a tubular oven in which temperature and air velocity within each tube are accurately controlled. The monofilaments are suspended within each tube by means of specially construced heat stabilized polypropylene holders (no metal contact), which facilitate handling and record keeping. Each filament is held in an attitude perpendicular to the air flow. Failures almost invariably occur in the middle of each filament. Oxidative stabilities of filaments aged in the tubular oven at a constant temperature and air flow were found to be dependent upon (a) distance of the filaments from the incoming air side and (b) whether the exposure was continuous or intermittent. If these parameters are kept constant, relatively good precision can be obtained. The 95% confidence level for a single observed value was found to be on the order of ±10% of the average oven stability within the whole oven and ±7% within a single tube. Precisions of about ±2.5% can be obtained by employing averages of 10 replicates exposed on the same specimen holder.     

An effect of moisture content on successive changes in the load-elongation curve for paper

Changes in the stress-strain curve for paper undergoing cyclic loading have been studied as a function of moisture content. It has been found that the extensional stiffness of the paper progressively decreases at both low and high moisture levels but progressively increases at intermediate moisture levels. The moisture content at which the transition from decreasing to increasing stiffness occurs (when passing from low to intermediate moisture content) has been determined and for the particular paper used in these experiments has been shown to correspond to a relative humidity of approximately 60%. It is postulated that at low and high moisture levels, conditions are not favorable for interfiber bond re-formation, whereas conditions are favorable for such reformation at intermediate moisture levels.     

Comparative study of methods of determining oil content of sunflower seed

An extraction-gravimetric method (AOCS Official Method Ai 3-75) was compared with 2 instrumental techniques, near-infrared reflec-tance (NIR) spectroscopy and wide-line nuclear magnetic resonance (NMR), for the determination of the oil content of oilseed-type hybrid sunflower seed. Eight sunflower seed samples of varying oil contents, replicated 5 times, were analyzed by the 3 procedures. The overall mean oil contents and standard deviations for the 8 samples were: AOCS method, 44.5% ± 0.33%; NMR, 44.8% ± 0.27%; and NIR, 44.2% ± 0.81%. Analysis of variance of the means of the 3 methods of analysis indicated no difference (p>0.05) in oil content due to the method. However, there was a difference (p>0.001) in total oil content due to replicated analyses of the same sample with the NIR method. With the AOCS and NMR methods, no effect (p>0.05) of replicated analyses of the same sample was found. The NMR method was more precise and repro-ducible than the other 2 methods. Although the NIR mean oil contents were not significantly different from the means of the other 2 methods, the coefficient of variations for all samples were consistently higher for the NIR analyses than for the AOCS and NMR analyses.     

Comparative analysis of methods of determining the oiling agent content in chemical fibres

A comparative analysis of methods of extracting oiling agent from chemical fibres showed that one extraction in a shaker could be used for all types of fibres investigated. Repeated extraction of the oiling agent using a Soxhlet apparatus can be recommended for all fibres investigated except for polyamide and polypropylene, since other compounds are extracted from these fibres together with the oiling agent. __________ Translated from Khimicheskie Volokna, No. 5, pp. 53–55, September–October, 2007.     

Comparison of fatty acid content of imported peanuts

Variability in fatty acid compositions of peanuts imported from six different countries into the United States were studied to determine their effect on processing and storage conditions. The oil content ranged from 44.1 to 50.4%. Major fatty acids, palmitic acid (C16:0), oleic acid (C18:l), and linoleic acid (C18:2) ranged from 8.6 to 12.7, 35.9 to 61.1 and 21.7 to 44.2%, respectively. Oleic and lino-leic acids together comprised ca. 78.0–83.0% of the total fatty acids. Highly significant differences (P<.01) in fatty acid compositions were obtained between samples and between locations (countries of origin). Indicators of stability of the peanut samples as measured by the oleic/linoleic acid ratio (O/L) and iodine value (IV) of the extracted peanut oils showed variable but significant differences (P <.05) between locations. Generally, higher O/L ratios corresponding to lower IV indicate better stability and longer shelf-life of the samples.     

An instrument for determining the total water content in air when extinguishing fires

An instrument suitable for measuring the total water content both as small liquid droplets and as vapour in the air, in water mist total flooding extinguishing tests, is presented. The instrument consists of a heater and a Vaisala humidity meter. The Vaisala humidity meter is capable of measuring relative humidity at temperatures up to 180°C. The instrument has a measuring range of 0–600g/m³, a sample rate of 1 L/min, a time constant of 5–10 s and an accuracy of ±40 g/m³. Accurate results are obtained when used outside the direct spray from a nozzle. If the instrument is placed in the spray the total water content can be either over‐ or underdetermined, depending on which part of the instrument faces the spray. Copyright © 1999 John Wiley & Sons, Ltd.     

Comparison of the direct and indirect wide-line nuclear magnetic resonance methods for determining solid fat content

A direct method of measuring the solid fat content by wide-line nuclear magnetic resonance (NMR) was compared with the conventional indirect wide-line NMR procedure. The direct method is based on the use of variable gate widths available on the Newport Analyser Mk IIIA. The results obtained for four different fats using the direct method did not differ significantly from those of the indirect method. As the direct method required additional measurements, was somewhat more complex theoretically and gave more variable results because of the weaker signal obtained at the wide gate, no real advantage could be found for its use.