Technical note: Comparison of dry matter measurements from handheld near-infrared units with oven drying at 60°C for 48 hours and other on-farm methods

Harvest Timing of Standing Corn Using Near-Infrared Reflectance Spectroscopy

Harvesting corn at the proper maturity is important for managing its nutritive value as livestock feed. Standing whole-plant moisture content is commonly utilized as a surrogate for corn maturity. However, sampling whole plants is time consuming and requires equipment not commonly found on farms. This study evaluated three methods of estimating standing moisture content. The most convenient and accurate approach involved predicting ear moisture using handheld near-infrared reflectance spectrometers and applying a previously established relationship to estimate whole-plant moisture from the ear moisture. The ear moisture model was developed using a partial least squares regression model in the 2021 growing season utilizing reference data from 610 corn plants. Ear moisture contents ranged from 26 to 80 %w.b., corresponding to a whole-plant moisture range of 55 to 81 %w.b. The model was evaluated with a validation dataset of 330 plants collected in a subsequent growing year. The model could predict whole-plant moisture in 2022 plants with a standard error of prediction of 2.7 and an R2P of 0.88. Additionally, the transfer of calibrations between three spectrometers was evaluated. This revealed significant spectrometer-to-spectrometer differences that could be mitigated by including more than one spectrometer in the calibration dataset. While this result shows promise for the method, further work should be conducted to establish calibration stability in a larger geographical region.

Influencia del método de secado (horno con convección vs horno microondas), sobre la composición nutricional de diferentes forrajes

La alimentación es el costo más importante en la producción animal. El objetivo de esta investigación fue comparar los métodos de secado en diferentes forrajes para la obtención de materia seca,  horno con convección de aire (HC) y horno microondas (HM), y su efecto sobre la composición nutricional de cada forraje. Se estudiaron seis forrajes comúnmente utilizados en la producción animal: maíz duro amarillo (MA) (Zea mays), pasta de soya (PS) (Glycine max L.), rechazo de verde (RV) (Musa × paradisiaca), ensilaje de maíz (EM) , alfalfa (AL) (Medicago sativa) y raigrás perenne (RP) (Lolium perenne). Se analizaron 40 muestras de cada forraje, cada forraje fue secado en HC, así como en HM y se estimó el contenido de materia seca (MS),  luego se le realizó un análisis bromatológico; Proteína bruta (Pb), extracto etéreo (EE), fibra bruta (Fb) y cenizas. Se utilizaron un análisis de varianza y prueba de Tukey (p<0.05) para determinar diferencias entre medias. Los resultados demuestran que existen diferencias (p<0.05) en el contenido de (MS), siendo el HM quien alcanza un mayor nivel de MS en MA, PS, RV y AL,  el RP tuvo valores más altos con el HC mientras que en el EM el contenido de MS no varía con los métodos de secado. Los métodos de secado tuvieron incidencia en la composición química de los forrajes, así por ejemplo de los 6 forrajes analizados en la Pb se observó diferencias en 5, Fb en 3, EE en 1 y cenizas en 4. Livestock feeding is the most important cost in animal production. The objective of this research is to compare the drying methods on different forages for obtaining dried matter, convection oven (CO) and microwave oven (MO), and the effect of each method on the nutritional composition of each forage. Six types of forages, commonly used in animal production, were studied: yellow hard corn (YC) (Zea mays), soybean paste (SP) (Glycine max L.), banana reject (BR) (Musa × paradisiaca), corn silage (CS), alfalfa (AL) (Medicago sativa) and perenial ryegrass (PR) (Lolium perenne). 40 samples of each forage  were analized, each forage was dried using CO and MO, and the dried matter content was estimated, then a bromatological analysis was done. Crude protein (Cp), ethereal extract (EE), crude fiber (Cf) and ashes. A variance analysis and tukey test (p<0.05)  were used to determine differences between means.  Results show that differences  (p<0.05) exist in the content of DM, being that MO reaches the highest level of DM in YC, SP, BR and AL, the PR had higher values with the CO while in the CS the content of DM does not vary with the drying methods. The drying methods had incidence on the chemical composition of forages, for example of the six forages analized  in the Cp differences were observed in 5, Cf in 3, EE in 1 and ashes in 4.

Selected Instrumental Techniques Applied in Food and Feed: Quality, Safety and Adulteration Analysis

This review presents an overall glance at selected instrumental analytical techniques and methods used in food analysis, focusing on their primary food science research applications. The methods described represent approaches that have already been developed or are currently being implemented in our laboratories. Some techniques are widespread and well known and hence we will focus only in very specific examples, whilst the relatively less common techniques applied in food science are covered in a wider fashion. We made a particular emphasis on the works published on this topic in the last five years. When appropriate, we referred the reader to specialized reports highlighting each technique's principle and focused on said technologies' applications in the food analysis field. Each example forwarded will consider the advantages and limitations of the application. Certain study cases will typify that several of the techniques mentioned are used simultaneously to resolve an issue, support novel data, or gather further information from the food sample.