Near infrared spectroscopy—a potentially useful method for rapid determination of fat and protein content in homogenized diets

Abstract

Objective: To investigate the potential of near-infrared re¯ectance (NIR) spectroscopy as a rapid and nondestructive method to determine total fat and protein in mixed, homogenized and freeze-dried human diets. Design: 29 students collected duplicate portions of their diet for four consecutive days. In addition, a detailed food diary was kept. The duplicate portions were analysed for total protein and fat content both by traditional chemical analysis (Kjeldahl and Folch methods) and through the recently developed NIR spectroscopy method. In addition, traditional computerized estimation of nutrient composition was performed. Results: Plotting of the NIR-predicted fat content against the chemically analysed fat content gave a correlation coef®cient of 0.99. Plotting of the NIR-predicted protein content against the Kjeldahl-analysed protein gave a correlation coef®cient of 0.81. Conclusion: NIR-spectroscopy seems to be able to determine fat content in mixed, homogenized diets to a high degree of accuracy. In surveys involving duplicate portion sampling this will save time and money. The prediction accuracy for protein was less convincing, but acceptable depending on the need for accurate individual data.

Noninvasive Determination of Protein Conformation in the Solid State Using Near Infrared (NIR) Spectroscopy

“…The 2000–2500 nm region (4000–5000 cm −1 ) has been reported to be useful for the study of protein structure,18,24,28 either to quantify the amount of protein in a particular sample or for protein structural characterization 13–18,28,30. Table 2 summarizes the assignments for the major NIR bands in the 2000–2500 nm region.…”

“…As most of the NIR bonds are overtone and combination bands of normal modes involving CH, OH, and NH bonds, there is the potential of NIR to monitor the structure of a protein. In fact, NIR has been extensively applied to the characterization of protein‐containing materials, including clinical, agricultural, and food applications 13–17. Recently, some studies have suggested that secondary structure information about proteins in the dried state could be obtained with NIR,18 but these reports did not compare native and denatured forms of a protein, so the utility of NIR for formulation development was not demonstrated.…”

Utility of Near-Infrared Reflectance Spectroscopy to Predict Nutrient Composition and In Vitro Digestibility of Total Mixed Rations

“…Likewise, moderate utility of predicting the NFC (R 2 = 0.83, SEP = 1.55% of DM) and fat content (R 2 = 0.81, SEP = 0.40% of DM) of TMR was observed using NIRS. Utility of NIRS to predict fat content of homogenized human diets (Almendingen et al, 2000) has been demonstrated; however, no literature references were found on the utility of NIRS to predict the NFC content of mixed human or animal diets.…”

“…Aufrere and Michalet-Doreau (1988) observed that NIRS could be used to predict in vitro DM digestibility (IVDMD) of forages, which is an indirect measure of animal performance. In mixed diets, Almendingen et al (2000) demonstrated that CP and fat content of homogenized human diets could be accurately predicted by NIRS. Likewise, White and Rouvinen-Watt (2004) developed robust NIRS equations to predict the DM, CP and fat content of mixed diets for mink.…”

Spectroscopic evaluation of the nutrient value of ground beef patties

“…The spectral range considered in this work was relatively narrower than the 400-2500 nm or 1100-2500 nm ranges used in most of the past studies, and the nutrients considered in this study had broader range of values compared to those used by Togerson et al (2003), Almendingen et al (2000), Schwarze (1997), and Clark and Short (1994). In spite of the low RPD for cholesterol, the PLSR models developed in this study resulted in low standard errors, and high R 2 values, comparable to other reported studies.…”