The main goal of this study was to investigate the potential of hyperspectral imaging in the near-infrared (NIR) range of 900–1700 nm for non-destructive prediction of chemical composition in lamb meat. Hyperspectral images were acquired for lamb samples originated from different breeds and different muscles. The mean spectra of the samples were extracted from the hyperspectral images and multivariate calibration models were built by using partial least squares (PLS) regression for predicting water, fat and protein contents. The models had good prediction abilities for these chemical constituents with determination coefficient (R 2 p ) of 0.88, 0.88 and 0.63 with standard error of prediction (SEP) of 0.51%, 0.40% and 0.34%, respectively. The feature wavelengths were identified using regression coefficients resulting from the PLSR analyses. New PLSR models were again created using the feature wavelengths and finally chemical images were derived by applying the respective regression equations on the spectral image in a pixel-wise manner. The resulting prediction maps provided detailed information on compositional gradient in the tested muscles. The results obtained from this study clearly revealed that NIR hyperspectral imaging in tandem with PLSR modeling can be used for the non-destructive prediction of chemical compositions in lamb meat. Industrial relevance The results obtained from this study clearly revealed that NIR hyperspectral imaging in tandem with PLSR modeling can be used for the non-destructive prediction of chemical compositions in lamb meat for the meat industry.

Non-destructive prediction and visualization of chemical composition in lamb meat using NIR hyperspectral imaging and multivariate regression

Diverse food-based applications of nuclear magnetic resonance (NMR) technology

Non-destructive determination of chemical composition in intact and minced pork using near-infrared hyperspectral imaging

The Kjeldahl method was introduced in 1883 and consists of three main steps: sample digestion, distillation, and ammonia determination (titration being the primary method). The Kjeldahl method uses sulfuric acid, a variety of catalysts, and salts to convert organically bound nitrogen in samples to ammonium with its subsequent measurement (Saez-Plaza et al., 2013). Today, this method is universally accepted and used in tens of thousands of laboratories throughout the world for nitrogen analysis in a wide variety of materials, such as foods, beverages, agricultural products, environmental samples, chemicals, biochemicals, and pharmaceuticals. However, successful analysis requires proper sampling and sample handling, which depend on the type of material. The Kjeldahl method has been validated and standardized for total (crude) protein estimation for a wide variety of food matrices, indirectly determined by their nitrogen content, and is the reference method adopted by many international organizations. The Kj...

An Overview of the Kjeldahl Method of Nitrogen Determination. Part II. Sample Preparation, Working Scale, Instrumental Finish, and Quality Control

Chemical-free assessment and mapping of major constituents in beef using hyperspectral imaging

A peer-verified method is presented for the determination of percent moisture and fat in meat products by microwave drying and nuclear magnetic resonance (NMR) analysis. The method involves determining the moisture content of meat samples by microwave drying and using the dried sample to determine the fat content by NMR analysis. Both the submitting and peer laboratories analyzed 5 meat products by using the CEM SMART system (moisture) and the SMART Trac (fat). The samples, which represented a range of products that meat processors deal with daily in plant operations, included the following: (1) fresh ground beef, high-fat; (2) deboned chicken with skin; (3) fresh pork, low-fat; (4) all-beef hot dogs; and (5) National Institute of Standards and Technology Standard Reference Material. The results were compared with moisture and fat values derived from AOAC-approved methods, 950.46 (Forced Air Oven Drying) and 960.39 (Soxhlet Ether Extraction).

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Rapid determination of moisture and fat in meats by microwave and nuclear magnetic resonance analysis--PVM 1:2003.

Ten laboratories participated in a collaborative study to determine the total moisture and fat in raw and processed meat products by microwave drying and nuclear magnetic resonance (NMR) spectroscopy. Meat products were prepared following the AOAC Method and analyzed using CEM Corp.'s SMART Trac Moisture and Fat Analysis system. SMART Trac provides moisture results by measuring the weight loss on drying by microwave energy. The dried sample is then analyzed by NMR spectrometry for fat content. Moisture and fat results are displayed and reported by the SMART Trac as a percentage (g/100 g). Microwave drying is an AOAC-approved reference method (Method 985.14), Moisture in Meat and Poultry Products. NMR spectrometry is a secondary technique used to determine the concentration of various constituents in biological, organic, or chemical samples. The study design was based on Youden's matched pair principle for collaborative tests. For the purposes of this study, 10 laboratories each tested 10 Youden matched pairs, for a total of 20 samples. The study samples represented a range of products processed daily in plant operations. Included were raw meat samples (beef, pork, chicken, and turkey) as well as processed meats (beef hot dog, pork sausage, and ham). The total moisture content of the undiluted samples, as received for the purposes of this study, was determined by AOAC Method 950.46 and ranged from 54.03 to 74.99%. The total fat content of the undiluted samples was determined by AOAC Method 960.39 and ranged from 1.00 to 29.79%. Statistical analysis of study results for total moisture yielded a relative standard deviation for repeatability (RSDr) range of 0.14 to 0.95% and a relative standard deviation for reproducibility (RSDR) range of 0.26 to 0.95%. Statistical analysis for total fat yielded similar RSDr and RSDR range of 0.74 to 4.08%. Results for turkey had higher RSDr and RSDR values, both at 12.6%, due to low fat content and possibly to the separation of the samples observed by some of the collaborators. Results demonstrate that microwave drying with NMR is a rapid, practical method providing results equivalent to AOAC Methods 950.46 (Forced Air Oven Drying) and 960.39 (Soxhlet Ether Extraction) in raw and processed meat products.

Determination of moisture and fat in meats by microwave and nuclear magnetic resonance analysis: collaborative study.

A peer-verified method is presented for the determination of percent moisture/solids and fat in dairy products by microwave drying and nuclear magnetic resonance (NMR) analysis. The method involves determining the moisture/solids content of dairy samples by microwave drying and using the dried sample to determine the fat content by NMR analysis. Both the submitting and peer laboratories analyzed various dairy products by using a CEM SMART system (moisture) and the SMART Trac (fat). The samples included milks, creams, ice cream mix, sour cream, yogurt, cream cheese, and mozzarella, Swiss, and cheddar cheeses. These samples represented a range of products that processors deal with in daily plant operations. The results were compared with moisture/solids and fat values derived from AOAC-approved methods.

Rapid determination of moisture/solids and fat in dairy products by microwave and nuclear magnetic resonance analysis.

A collaborative study was conducted to determine the protein content of raw and processed meat products by a protein-tagging and colorimetric technique. Meat products were prepared following AOAC Official Method 983.18 and analyzed using CEM Corporation's Sprint Rapid Protein Analyzer. Sprint provides protein results by combining an accurately weighed test portion with a known amount of dye-binding agent. The dye-binding agent binds with the lysine, histidine, and arginine, as well as the n-terminus of the proteins commonly found in raw meat and processed meat products. Results are displayed and reported by the Sprint as a percentage (g/100 g) of protein. Ten blind duplicate study samples were sent to 10 collaborating laboratories in the United States. The within-laboratory (repeatability) relative standard deviation (RSD(r)) ranged from 0.91 to 3.04%, and between-laboratories (reproducibility) relative standard deviation (RSDR) ranged from 1.50 to 3.41% for protein. The method is recommended for Official First Action.

Cindy R Moser

Papers

Rapid determination of moisture and fat in meats by microwave and nuclear magnetic resonance analysis--PVM 1:2003.

Determination of moisture and fat in meats by microwave and nuclear magnetic resonance analysis: collaborative study.

Rapid determination of moisture/solids and fat in dairy products by microwave and nuclear magnetic resonance analysis.

Method for the rapid determination of protein in meats using the CEM Sprint protein analyzer: collaborative study.