Comparison of different methods to quantify fat classes in bakery products

The definition of fat differs in different countries; thus whether fat is listed on food labels depends on the country. Some countries list crude fat content in the ‘Fat’ section on the food label, whereas other countries list total fat. In this study, three methods were used for determining fat classes and content in bakery products: the Folch method, the automated Soxhlet method, and the AOAC 996.06 method. The results using these methods were compared. Fat (crude) extracted by the Folch and Soxhlet methods was gravimetrically determined and assessed by fat class using capillary gas chromatography (GC). In most samples, fat (total) content determined by the AOAC 996.06 method was lower than the fat (crude) content determined by the Folch or automated Soxhlet methods. Furthermore, monounsaturated fat or saturated fat content determined by the AOAC 996.06 method was lowest. Almost no difference was observed between fat (crude) content determined by the Folch method and that determined by the automated Soxhlet method for nearly all samples. In three samples (wheat biscuits, butter cookies-1, and chocolate chip cookies), monounsaturated fat, saturated fat, and trans fat content obtained by the automated Soxhlet method was higher than that obtained by the Folch method. The polyunsaturated fat content obtained by the automated Soxhlet method was not higher than that obtained by the Folch method in any sample.     

Processing and characterisation of low cost Balistid fish Sufflamen capistratus liver oil for edible purpose

The physico-chemical properties of liver oil from low cost Balistid fish Sufflamen capistratus extracted by Soxhlet, Bligh and Dyer, direct steaming, solar extraction and Mc Gill and Moffat methods were assessed. The oil yield was high (70.3%) in Soxhlet method when compared with other methods. The physical properties such as solidification point, melting point, refractive index and moisture content of the extracted oil samples were differed between methods. The chemical properties like the acid value, free fatty acid (FFA) level and carotenoid content of the individual oil samples were showed extraction methods dependant variation. Fatty acid content was also showed variation between methods; polyunsaturated fatty acid (PUFA) content was high (23.07%) in Bligh and Dyer method. In all the oil samples, fat soluble vitamin K was more when compared with the other tested vitamins. Irrespective of methods of extraction, permissible level of heavy metals and minerals were recorded in the oil samples.     

Nondestructive Prediction of Moisture and Sodium Chloride in Cold Smoked Atlantic Salmon (Salmo salar)

ABSTRACT: Salt and moisture contents in cold-smoked salmon were determined using short-wavelength near-infrared (SW-NIR) reflectance spectroscopy (600 to 1100 nm). Partial least square (PLS) regression models yielded the best results among 3 linear regression methods tested. Back-propagation neural networks (BPNN) exhibited a somewhat better capability to model salt and moisture concentrations (Salt: R²= 0.824, RMS = 0.55; Moisture: R²= 0.946, RMS = 2.44) than PLS (Salt: R²= 0.775, RMS = 0.63; Moisture: R²= 0.936, RMS = 2.65). Selection of samples from different axial locations on a fish did not affect the prediction error for salt or WPS but affected the prediction error for moisture.     

On-line versus off-line NIRS analysis of intact olives

Visible/near-infrared calibrations were developed for the determination of the quality parameters (fat content, moisture and free acidity) of intact olive fruits. The reflectance spectra were acquired in two different instruments (diode-array versus grating monochromator based instruments). The grating monochromator based instrument was used at the laboratory (off-line analysis), whereas the portable diode-array based device was placed on top of a conveyor belt set to simulate measurements in an olive oil mill plant (on-line analysis). Partial least squares (PLS) regression and least squares support vector machine (LS-SVM) were used for the development of the calibration models. A total of 174 samples were prepared for the calibration (N = 122) and validation (N = 52) sets. The root mean square error of prediction (RMSEP) and the residual predictive deviation (RPD) values were better using the diode-array instrument and applying the PLS regression method for the fat content parameter while for the free acidity and moisture content, the LS-SVM algorithm gave the best results. The results obtained seems to suggest the viability of the on-line system, instead of the off-line analysis, for the determination of physicochemical composition in intact olives.     

Prediction of the intramuscular fat and protein content of freeze-dried ground meat from cattle and sheep using near-infrared spectroscopy (NIRS)

This study assessed the ability of near-infrared spectroscopy to predict intramuscular fat (IMF) and protein content of freeze-dried ground beef and sheep meat determined using the modified Soxhlet extraction and Dumas combustion, and ascertain if robust calibration models could be developed for both assays using the combined spectral data from both species. Samples were sourced from sheep and cattle slaughtered for a variety of experiments, which covered a range in age, diet fed and carcase cut. All samples were scanned using a benchtop NIRS instrument to develop calibration models, a subset of which was used for later validation. Intramuscular fat and protein content of samples ranged from 5.1 to 32.8 and 63.4 to 89.8, respectively, with combined species of the R² values of 98.4 and 96.5 (RMSE 0.74 and 0.76) for IMF and protein respectively. Additionally, animal age and carcase cut were found to have no significant impact on the precision of prediction models. Results from our study showed that individual species as well as combined calibration models can be successfully developed for predicting IMF and protein content of freeze-dried ground beef and sheep meat.     

Determination of fat,protein, moisture,and salt content of Cheddar cheese using mid-infrared transmittance spectroscopy

The objective of our work was to develop and evaluate the performance of a rapid method for measuring fat, protein, moisture, and salt content of Cheddar cheese using a combination mid-infrared (MIR) transmittance analysis and an in-line conductivity sensor in an MIR milk analyzer. Cheddar cheese was blended with a dissolving solution containing pentasodium triphosphate and disodium metasilicate to achieve a uniform, particle-free dispersion of cheese, which had a fat and protein content similar to milk and could be analyzed using a MIR transmittance milk analyzer. Annatto-colored Cheddar cheese samples (34) from one cheese factory were analyzed using reference chemistry methods for fat (Mojonnier ether extraction), crude protein (Kjeldahl), moisture (oven-drying total solids), and salt (Volhard silver nitrate titration). The same 34 cheese samples were also dissolved using the cheese dissolver solution, and then run through the MIR and used for calibration. The reference testing for fat and crude protein was done on the cheese after dispersion in the dissolver solution. Validation was done using a total of 36 annatto-colored Cheddar cheese samples from 4 cheese factories. The 36 validation cheese samples were also analyzed using near-infrared spectroscopy for fat, moisture, and the coulometric method for salt in each factory where they were produced. The validation cheeses were also tested using the same chemical reference methods that were used for analysis of the calibration samples. Standard error of prediction (SEP) values for moisture and fat on the near-infrared spectroscopy were 0.30 and 0.45, respectively, whereas the MIR produced SEP values of 0.28 and 0.23 for moisture (mean 36.82%) and fat (mean 34.0%), respectively. The MIR also out-performed the coulometric method for salt determination with SEP values of 0.036 and 0.139 at a mean level of salt of 1.8%, respectively. The MIR had an SEP value of 0.19 for estimation at a mean level of 24.0% crude protein, which suggests that MIR could be an easy and effective way for cheese producers to measure protein to determine protein recovery in cheese making.     

Comparison of different methods for total lipid quantification in meat and meat products

This study was aimed to evaluate the efficiency of six extraction methods for the quantification of total lipid content in meat and meat products: standard Soxhlet method (with and without previous acid hydrolysis), continuous Soxhlet method (with and without previous acid hydrolysis), and those methods based in the use of a mixture of chloroform and methanol, and described by Folch, Less, and Sloane (1957) and Bligh and Dyer (1959). Lipid content was determined in nine different meat products with different fat contents and physico-chemical features: cooked turkey breast, fresh pork loin, cooked ham, dry-cured ham, mortadella, beef burger, fresh sausage, dry-cured sausage and salami. The most effective methods for determining fat content in the studied meat products were the method described by Folch et al. (1957) and the Soxhlet with previous acid hydrolysis method. The Soxhlet method without previous acid hydrolysis adequately extracted lipids only in those meat products with very high fat content. The use of the method described by Bligh and Dyer (1959) gave rise to the lowest lipid contents in all the studied meat products.     

Moisture adsorption isotherms of guar (Cyamposis tetragonoloba) grain and guar gum splits

Moisture adsorption isotherms of guar grain and guar gum splits were determined at 10, 20, 30 and 40 °C and 23-96% relative humidities using gravimetric method. The sorption data were fitted to six well-known sorption isotherm models (modified Chung-Pfost, modified Halsey, modified Henderson, modified Oswin, Chen-Clayton, and GAB models) using non-linear least square method. The GAB model was found the most satisfactory for representation of the equilibrium moisture content data for guar grain and guar gum splits. The equilibrium moisture content of guar gum splits was found to be significantly higher (p < 0.05) than that of guar grain. The isosteric heat of sorption was determined from the equilibrium moisture adsorption data using Clausius-Clapeyron type equation. Exponential relationship described well the dependence of isosteric heat of sorption on the equilibrium moisture content. The enthalpy-entropy compensation theory applied to sorption isotherms indicated enthalpy controlled sorption process.     

Development and Analytical Validation of Robust Near-Infrared Multivariate Calibration Models for the Quality Inspection Control of Mozzarella Cheese

This paper proposed and validated robust diffuse reflectance near-infrared methods for the direct determination of fat and moisture in cow mozzarella cheeses using partial least squares regression. They were developed under the realistic conditions of routine analysis in a state laboratory of quality inspection control and were used for analyzing a great variety of mozzarella samples manufactured by different manufacturing procedures and originating from the whole state of Minas Gerais, Brazil (more than 100 different producers). A robust methodology was implemented, including the detection of outliers and the harmonization of the multivariate concepts with the traditional univariate guidelines. The models were constructed in the ranges from 38.7 to 58.0 % w/w on dry basis for fat and from 41.5 to 55.1 % w/w for moisture, providing root mean square errors of prediction of 2.1 and 0.9 %, respectively. Both methods were validated through the estimation of figures of merit, such as linearity, trueness, precision, analytical sensitivity, ruggedness, bias, and residual prediction deviation. Once the methods were adopted, their performances were monitored for approximately 1 year through control charts and were considered satisfactorily stable with prediction errors within the established limits. Beyond these specific methods, it was also pursued to present a complete methodology for multivariate analytical validation, an important aspect for the implementation of near-infrared spectroscopy methods in the routine of food quality inspection.     

Indirect measurement of the fat content of beef mince using the Infra-Tester

A technique for the indirect estimation of the fat content of beef mince by the direct measurement of moisture content was evaluated. Samples of commercially produced beef mince ranging from 7 to 25% fat were analysed for moisture content using infra-red heating, and for fat and moisture content by standard laboratory procedures. Moisture content measured by infra-red heating using the Infra-Tester was highly correlated with fat content measured by the standard method and could be used as a rapid and inexpensive method of predicting the fat content of beef mince.     

Texture and appearance of dry cured ham as affected by fat content and fatty acid composition

The relationship between texture and appearance characteristics and the moisture, intramuscular fat (IMF) content and fatty acid composition of dry cured Iberian ham was studied using principal component analysis. Intramuscular fat content positively influenced the proportion of oleic acid (R=0.5578), and exhibited a negative relationship with linoleic and arachidonic acids (R=−0.5215 and −0.5770 respectively). IMF content also had a positive influence on some texture and appearance traits of ham, such as oiliness, brightness, juiciness and marbling. However, it was negatively related to dryness, fibrousness and hardness. Moisture displayed no relationship with juiciness, dryness or any other textural or appearance trait. Therefore, within the ranges of fat content and moisture found in the present study, IMF content has a stronger influence on the texture of ham than the degree of dehydration.     

Comparison of chemical composition of meat determined at eight laboratories

Sixteen minced samples of lean beef M. semimembranosus and M. gracilis were analysed for nitrogen, fat, moisture, collagen, ash and pH using recommended procedures in eight European Communitie' (EC) meat research laboratories. Differences between replicate determinations within laboratories were often larger than suggested in reference methods although they were smaller than the differences between laboratories. Moisture and pH were determined most consistently, collagen least consistently.     

Nondestructive Determination of Moisture and Sodium Chloride in Cured Atlantic Salmon (Salmo salar) (Teijin) Using Short-wavelength Near-infrared Spectroscopy (SW-NIR)

ABSTRACT: Moisture (49.70 to 74.20% w/w) and salt (0.13 to 12.30% w/w) concentrations in cured Atlantic salmon ( Salmo salar ) or teijin were determined by short-wavelength near-infrared (SW-NIR) reflectance spectroscopy (600 to 1100 nm) using partial least square regression (PLS) and artificial neural networks (ANN) calibration methods. ANN and PLS yielded similar results (Salt: ANN RMS = 1.43% w/w, PLS RMS = 1.37% w/w; Water, ANN RMS = 2.08% w/w, PLS RMS = 2.04% w/w). Sampling the dorsal or ventral portion of the fish did not appear to affect the prediction error of the salt or moisture models.     

Effect of drying method on the moisture sorption isotherms for Inonotus obliquus mushroom

Moisture sorption isotherms of Inonotus obliquus mushroom were studied over a selected temperature range (20-50 °C). Sigmoid sorption isotherms were observed for these samples. The sorption data were analyzed using various conventional models. The Oswin model was found to be the best model for predicting the equilibrium moisture content of mushroom in the range of water activity 0.08-0.96. The monolayer moisture content decreased as temperature increased and was affected by the drying method used. The net isosteric heat of sorption was determined using the Clausius-Clapeyron equation and the value decreased with increase in moisture content of mushroom.     

Marbling, intramuscular fat and meat colour of Dutch pork

The amounts of intramuscular (i.m.) fat in the lean meat of the lumbar region of 21 slaughterpigs have been determined according to the Soxhlet method as a reference, and compared with those determined with the faster Foss-let procedure. These methods were highly correlated, over the lower range of fat concentrations (0·30-4·35%) studied. Although the Foss-Let values were on average slightly lower than the Soxhlet values, the Foss-Let procedure can be recommended for the determination of i.m. fat in pork. Furthermore, chemically determined i.m. fat was found to be significantly correlated with marbling. The sensory evaluations of pork colour were significantly correlated with each other and with the instrumentally determined colour lightness.     

Effects of hot boning and moisture enhancement on the eating quality of cull cow beef

The effects of chilling method and moisture enhancement were examined for improving eating quality of semimembranosus (SM) and longissimus lumborum (LL) from 62 cull beef cows. Chilling method included hot boning muscles after 45 to 60 min postmortem or conventional chilling for 24 h. Moisture enhancement included 1) a non-injected control (CONT) or injection processing (10% of product weight) using 2) Sodium Tripolyphosphate/salt (Na/STP), 3) Sodium Citrate (NaCIT), 4) Calcium Ascorbate (CaASC), or 5) Citrus Juices (CITRUS). Chilling method by moisture enhancement treatment interactions (P < 0.09) were due to decreased hue, chroma and sarcomere length values in hot boned vs. conventionally chilled product (SM and LL) for CaASC vs. other moisture enhancement treatments. Chilling method by moisture enhancement treatment interactions (P < 0.05) were due to decreased shear force and increased tenderness in conventionally chilled vs. hot boned LL using CaASC vs. Na/STP. Moisture enhancement can improve tenderness of cull cow beef depending on combinations of chilling method and moisture enhancement treatments used.     

Moisture and fat content,marbling level and color of boneless rib cut from Nellore steers varying in maturity and fatness

This study analyzed rib steaks (M. longissimus thoracis) of Nellore steers (n = 60) for intramuscular moisture and fat content, marbling level, and visual and instrumental color. Carcass sides were classified on the kill floor according to teeth maturity (2, 4 and 6 permanent incisors), and fatness (2 — slight and 3 — average). The cranial end of the boneless cut was aged for 14 days, and frozen. Steaks of 2.5 cm thick were cut and thawed for analysis. Moisture and fat content were determined in minced lean. CIE color was measured with a MiniScan XE™, and visually evaluated by an eight-member panel, which also assessed marbling. In this type of cattle and ranges of maturity and fatness considered, increasing either maturity or fatness causes a slight reduction in moisture and an increment in lipid content. But neither maturity nor fatness seems to affect the visual perception of meat color on display.     

Moisture, Fat and Cholesterol Content of Some Raw; Barbecued and Cooked Organ Meats of Beef and Mutton

The effect of barbecueing and conventional cooking methods on moisture, fat and cholesterol content in brain, heart, kidney, liver, and tongue of local Iraqi; beef and mutton were studied. Moisture, fat and cholesterol content differed significantly (P ≤ 0.05) between raw and barbecued samples and between raw and cooked samples of both beef and mutton organ meats, except for those mentioned. The lower moisture in barbecued and cooked samples probably caused a relative increase in fat and cholesterol content. Minor differences were observed in raw, barbecued and cooked organ meats between beef and mutton in terms of moisture, fat and cholesterol content at similar animal ages.     

Rapid determination of total fats and fat-soluble vitamins in Parmigiano cheese and salami by SFE

Supercritical fluid extraction (SFE) was used to determine total fat and fat-soluble vitamins in Parmigiano cheese and salami. Extracts were obtained quickly and effectively to gravimetrically determine total fat. The results were compared with traditional methods and the quantity extracted and collected by supercritical carbon dioxide (SC-CO₂) was statistically equivalent to the Soxhlet extraction. In addition, the use of SFE as a preparative analysis was tested to determine in a rapid and simultaneous way the fat-soluble vitamin extracted by SFE and subsequently determined by HPLC. The extractability of vitamins by SFE was comparable to the official methods. α-tocopherol was higher probably because SC-CO₂ extraction is necessarily conducted in the absence of light and oxygen, and lower temperature than traditional methods. RSD% was lower than 20% for total fat determination, while it was sometimes higher for fat-soluble vitamins determination.     

Non-Destructive Determination of Fat and Moisture in Whole Atlantic Salmon by Near-Infrared Diffuse Spectroscopy

A near-infrared spectrometer equipped with an interactance optical fiber probe was used to determine the average crude fat and moisture content in the muscle of whole Atlantic salmon (Salmo salar). The fat contents were 8.8—19.2% and moisture 61.0—70.8%, and fish weight range 1.0—5.7 kg. A partial least square regression including 49 salmon resulted in root mean square error of cross validation of 1.12% fat (R = 0.87) and 0.98% moisture (R = 0.86). Results showed that NIR interactance was a suitable non-destructive screening method for fat and moisture content in farmed Atlantic salmon.