Prediction of Mineral Composition in Commercial Extruded Dry Dog Food by Near-Infrared Reflectance Spectroscopy

Abstract

Simple SummaryMineral content in dog food is essential to ensure animals’ adequate development and health status, but its analysis is time-consuming and companies are not always equipped with the technology to perform it. Near-infrared spectroscopy (NIRS) is a rapid, objective, easy to manage, chemical-free, and non-destructive method that is already available in the food industry for the prediction of gross composition (e.g., moisture, protein, fat, etc.). However, this technological approach is not yet used for the prediction of minerals because there is scarce information regarding the feasibility of NIRS to predict minerals in pet food. Results of this study revealed that, among all minerals analyzed, adequate NIRS prediction models were obtained for S and K for extruded dry dog food. The development of prediction models for mineral content in dry dog food opens the possibility of on-line and at-line analyses of minerals in the products during the manufacturing process, which could help the manufacturing decision support system in the pet food industry.AbstractThe pet food industry is interested in performing fast analyses to control the nutritional quality of their products. This study assessed the feasibility of near-infrared spectroscopy to predict mineral content in extruded dry dog food. Mineral content in commercial dry dog food samples (n = 119) was quantified by inductively coupled plasma optical emission spectrometry and reflectance spectra (850–2500 nm) captured with FOSS NIRS DS2500 spectrometer. Calibration models were built using modified partial least square regression and leave-one-out cross-validation. The best prediction models were obtained for S (coefficient of determination; R2 = 0.89), K (R2 = 0.85), and Li (R2 = 0.74), followed by P, B, and Sr (R2 = 0.72 each). Only prediction models for S and K were adequate for screening purposes. This study supports that minerals are difficult to determine with NIRS if they are not associated with organic molecules.

Application of a Handheld Near-Infrared Spectrometer to Predict Gelatinized Starch, Fiber Fractions, and Mineral Content of Ground and Intact Extruded Dry Dog Food

“…Furthermore, for the manufacturing companies, it is important to monitor the mineral content of foods, for its impact on the animals’ health and growth [ 11 ]. Both macrominerals and trace minerals exert important functions in the maintenance of homeostasis [ 12 , 13 , 14 ], and their excess or deficiency can impair animals’ health [ 15 ]. Thus, the mineral content of dog food needs to be frequently monitored with an easy and fast method.…”

Miniaturized Fluorimetric Method for Quantification of Zinc in Dry Dog Food

“…Compared to a recent work using a microplate colorimetric assay [ 13 ], the strategy proposed here is more straightforward as it does not require the inclusion of ion masking reagents or the application of partitioning correction calculations. Compared to the fast method proposed by Goi et al [ 14 ], our approach provides the value of the total Zn as a digestion process is performed before the fluorimetric reaction while the near-infrared reflectance spectroscopy-based method can only detect Zn associated with organic complexes, providing underestimated results for dog food supplemented with inorganic forms of Zn. Finally, compared to other approaches that applied AAS [ 26 ] or ICP-MS [ 7 ], the method proposed here allows the simultaneous determination of up to 96 samples, without requiring expensive equipment or application of the standard addition method.…”

“…Nevertheless, these methods require trained personnel and high-cost/high maintenance equipment. Thus, there are some rapid and low-cost methods for zinc determination, based on fluorimetric [ 11 ] or colorimetric assays [ 12 , 13 ] and on near-infrared reflectance spectroscopy [ 14 ].…”

Mineral Composition of Cereal and Cereal-Free Dry Dog Foods versus Nutritional Guidelines

“…In pet food, it is common practice to supplement diets with a Zn level above the minimum requirement to prevent symptoms of deficiency [12]. Goi et al [68] found that in the tested extruded commercial dog foods the amounts of Zn were greater than the established safe limit, and the average content of all foods was close to the recommended maximum (mean 19.02 g/100 g DM). In turn, a mean above the MLL of Zn in twenty dry complete dog foods for adult dogs and six foods for puppies (mean 32.5 and 27.6 g/100 g DM, respectively) was found in a study conducted by Pereira et al [11].…”