Detecting Low Concentrations of Nitrogen-Based Adulterants in Whey Protein Powder Using Benchtop and Handheld NIR Spectrometers and the Feasibility of Scanning through Plastic Bag

Nitrogen-rich adulterants in protein powders present sensitivity challenges to conventional combustion methods of protein determination which can be overcome by near Infrared spectroscopy (NIRS). NIRS is a rapid analytical method with high sensitivity and non-invasive advantages. This study developed robust models using benchtop and handheld spectrometers to predict low concentrations of urea, glycine, taurine, and melamine in whey protein powder (WPP). Effectiveness of scanning samples through optical glass and polyethylene bags was also tested for the handheld NIRS. WPP was adulterated up to six concentration levels from 0.5% to 3% w/w. The two spectrometers were used to obtain three datasets of 819 diffuse reflectance spectra each that were pretreated before linear discriminant analysis (LDA) and regression (PLSR). Pretreatment was effective and revealed important absorption bands that could be correlated with the chemical properties of the mixtures. Benchtop NIR spectrometer showed the best results in LDA and PLSR but handheld NIR spectrometers showed comparatively good results. There were high prediction accuracies and low errors attesting to the robustness of the developed PLSR models using independent test set validation. Both the plastic bag and optical glass gave good results with accuracies depending on the adulterant of interest and can be used for field applications

Floral and geographical origin identification of Hungarian honey with electronic tongue and classical analytical methods

Honey has been widely used for health care and as sweetener since the ancient times. Due to its great nutritional value and its high price, honey is one of the most adulterated products on the market. Therefore, there is a need to develop new quick measurement methods to recognize the adulteration. Almost 80 authentic honey samples of different floral and geographical origins were collected for our experiments, focusing mainly on Hungarian honey. Various analytical methods were used for the determination of the nutritional values of the honey samples, e.g. antioxidant capacity, polyphenol content, ash content, pH, conductivity, etc. These measurements aim to complete the scarcely available data on Hungarian honeys. In addition, we determined sensory properties by color and electronic tongue analyses. Electronic tongue enables easy sample preparation and results are delivered in a short time. Evaluating the results by different multivariate statistical methods, determination of the floral and geographical origin of the samples was possible based on the results of the electronic tongue measurements. The results achieved with these classifications methods have proven by building up a robust database electronic tongue can be used for origin authentication of domestic honey samples

Effects of Non-uniform Kernel Moisture Content on Moisture Measurement of Corn

The price paid for corn is usually based on 15.0 or 15.5 percent moisture content. However, corn must be dried below 13 percent moisture to ensure safe storage for a year or more. In the U.S., such stored corn cannot be directly remoistened before selling it, but it can be mixed with moist new-crop corn. Accurate moisture measurement of mixtures of dry and moist corn is important to permit adjustment of blending ratios to maximize profitability, but grain moisture meters are less accurate for mixtures of wet and dry grain. This research evaluated the differences between dielectric-type moisture meter results for mixed and equilibrated corn samples at different moisture levels and different measurement frequencies. Equilibrated grain samples tended to give lower moisture results than recently mixed grain samples - especially in the 1 to 10 MHz region. These differences permitted detection of mixtures by using moisture measurements at two frequencies