Fourier Transform Infrared Spectroscopy (FTIR) for MUN analysis in normal and adulterated Milk

Abstract

The objective of this study was to evaluate the CombiScope FTIR equipment based on Fourier Transform Infrared methodology (FTIR), to assess the content of milk urea nitrogen (MUN) in Brazil. Repeatability and reproducibility of CombiScope™ FTIR (Delta Instruments), and comparison with an enzymatic automated method (Chemspec® 150; Bentley Instruments) were tested to measure raw milk urea nitrogen (MUN). Additionally, MUN levels stability after storage of raw milk samples at 4°C, and 20°C for up to 15 days, and capability and precision to detect extraneous urea added as an adulterant to the milk were evaluated by FTIR equipment. There was a high correlation coefficient for the analysis of MUN by FTIR equipment, when compared with the automated enzymatic method, with no significant difference between both. MUN concentration in raw milk remained stable at temperatures of 4°C for up to 15 days of storage, but after 3 days of storage at 20°C there was an increase in the MUN levels. The CombiScope FTIR equipment proved to be a reliable method for analysis of MUN content in raw milk. However, results for MUN were not linear with the amount of extraneous urea added to raw milk, having a significant difference for samples when 40mg/dL of urea was added to milk.Keywords: milk, validation, milk urea nitrogen, infrared spectroscopy, FTIR Palavras-chave: leite, validação, nitrogênio uréico no leite, espectroscopia no infravermelho, FTIR RESUMO O objetivo deste estudo foi realizar a avaliação do CombiScope™ FTIR (Delta Instruments), um equipamento baseado na espectroscopia de infravermelho por metodologia em Transformada Fourier (FTIR) para a avaliação do teor de nitrogênio uréico no leite (NUL) cru produzido no

The evolving role of Fourier-transform mid-infrared spectroscopy in genetic improvement of dairy cattle

“…Other notable FT-MIR research includes studies of individual fatty acids and milk proteins [8,9], and studies of milk properties related to manufacturing, especially coagulation and other cheese-making properties [10][11][12]. Further studies have focussed on traits not directly measurable in milk, including those related to pregnancy [13,14], energy status [15,16], nitrogen outputs [17] and methane emissions [18][19][20]. Such applications demonstrate that FT-MIR spectra can be used to predict a wide range of traits, including highly topical traits that are important to animal welfare and the environment.…”

Supplementation with different non-fiber carbohydrate sources in dairy cow diets with high or low rumen-undegradable protein content

“…Samples of milk per cow were collected in plastic bottles containing preservative (2-bromo-2-nitropropane-1,3-diol -10mg/50mL/milk) in four consecutive milkings using a milk collector coupled to the milk-line (GEA®, Düsseldorf, Germany). Milk samples were stored and analyzed for milk fat, total protein by infrared analyses ((Bentley 2000 -Bentley Instruments Inc., Chaska, MN) and milk urea nitrogen (MUN) by Fourier Transform Infrared methodology (CombiScope FTIR advanced / Delta Instruments, Drachten, Netherlands) (Oliveira a et al, 2012). Milk production corrected for 35g/kg of fat (FCM3.5) was obtained using the equation proposed by Gaines (1928): FCM3.5= (0.5255 x MP) + (16.425 x FatP), in which LCG3.5 is the milk production corrected for 35g/kg of fat (Kg/day); MP is the milk production (kg/day); FatP is the fat production (kg/day).…”

Ocorrência de não conformidades físico-químicas e microbiológicas em leite e derivados no estado de Minas Gerais, no período de 2011 a 2015

“… Uma crescente demanda do mercado consumidor por produtos de alta qualidade, que mantenham suas características, revela a necessidade de análises que garantam a segurança microbiológica na produção e a vida de prateleira do produto. O setor laticinista também demanda produtos lácteos de alta qualidade, levando à progressiva adaptação desse importante segmento às exigências do mercado consumidor (Oliveira et al, 2012). A qualidade e o maior rendimento de produtos lácteos estão intimamente relacionados à qualidade da matéria-prima, desde a sua obtenção até a sua entrada na linha de processamento (Teodoro e Oliveira, 2015).…”