scholarly journals Whey Protein Powder Analysis by Kjeldahl and Mid-Infrared Spectroscopy

Author(s):  
Rose Saxton

There is an ever-expanding number of high protein dietary supplements marketed as beneficial to athletes, body builders, infant formulas, elder care, and animal feed. Consumers will pay more for products with high protein per serving data on their nutritional labels, making the accurate reporting of protein content critical to customer confidence. The Kjeldahl Method (KM) is the industry standard to quantitate dairy proteins, but the result is based on nitrogen content, which is an approximation of nitrogen attributable to protein in milk. Optical spectroscopy is commonly used for quality control measurements and has been identified as having the potential to complement the KM as a more nuanced testing measure of dairy protein. Infrared (IR) spectroscopy offers advantages over the KM in that IR provides an accurate representation of protein content in dairy products, and the results can be achieved very quickly. Protein analysis by IR has been used to study protein degradation in aged cheeses, and milk whey powder adulteration in whey protein concentrate supplements. The hypothesis of this thesis is that if mid-infrared (MIR) spectroscopy can be used to characterize individual whey proteins, then MIR should be applicable to qualitative analysis of protein powders and quality control monitoring of protein powder products for adulteration by inexpensive protein or amino acids. Protein powder analysis by KM revealed that the calculated total percent protein of the five protein powders tested was lower than the value stated on the product label, the percent variation between label protein content and that of the KM ranged from 2.9% to 9.5%. MIR spectroscopy spectra of four whey protein standards and four other protein standards provided qualitative characterization of each protein by amide I and amide II peak absorbance wavenumber. Product tampering by third-party manufacturers is an issue, due to the lack of United States Food and Drug Administration regulation of nutraceutical products, permitting formulators to add low-cost nitrogen-containing components to artificially inflate the KM approximated protein content of the products. Protein powders have been found to be doped with the amino acids glycine, leucine, and glutamic acid and inexpensive proteins, like bovine serum albumin. Controlled doping experiments were conducted with each of the above listed adulterants to assess the effectiveness of MIR spectroscopy to rapidly detect product tampering. Protein doping experiments revealed that as BSA amounts were increased, the amide I/II peak shape changed from the broad protein powder peaks to the narrower BSA peaks. Amino acid doping experiments revealed that the limit of detection for MIR spectroscopy, for the three amino acids used in this study, is 25%. MIR spectroscopy results may offer product quality assurance that is complementary to dairy protein measurement by the KM.

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1033
Author(s):  
Rose Saxton ◽  
Owen M. McDougal

There is an ever-expanding number of high protein dietary supplements marketed as beneficial to athletes, body builders, infant formulas, elder care, and animal feed. Consumers will pay more for products with high protein per serving data on their nutritional labels, making the accurate reporting of protein content critical to customer confidence. The Kjeldahl method (KM) is the industry standard to quantitate dairy proteins, but the result is based on nitrogen content, which is an approximation of nitrogen attributable to protein in milk. Product tampering by third-party manufacturers is an issue, due to the lack of United States Food and Drug Administration regulation of nutraceutical products, permitting formulators to add low-cost nitrogen-containing components to artificially inflate the KM approximated protein content in products. Optical spectroscopy is commonly used for quality control measurements and has been identified as having the potential to complement the KM as a more nuanced testing measure of dairy protein. Mid-infrared (MIR) spectroscopy spectra of eight protein standards provided qualitative characterization of each protein by amide I and amide II peak absorbance wavenumber. Protein doping experiments revealed that as protein amounts were increased, the amide I/II peak shape changed from the broad protein powder peaks to the narrower peaks characteristic of the individual protein. Amino acid doping experiments with lysine, glutamic acid, and glycine, determined the limit of detection by MIR spectroscopy as 25%, suggesting that MIR spectroscopy can provide product quality assurance complementary to dairy protein measurement by the KM.


Author(s):  
Virgilio De Carvalho dos Anjos

Mid infrared (MIR) spectroscopy was combined with multivariate approaches Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression to assess modifications in spectral profile of whey protein concentrate (WPC) powder due to changes in formulation level using caffeine, creatine and lactose, simulating fraud. Adulterations were made by replacing WPC in different levels from 5 to 50% (w/w - 5% steps) with three adulterants in separate. The spectra comparison of the samples allowed the identification of peaks associated to characteristic chemical bonds of each adulterant. PCA was carried out and 89% of the total variability of the spectral data was explained by three principal components, which allowed the confirmation of variables influencing each sample mixture and validating the spectral observations. Above 20% decrease in WPC content (20% adulteration), it was possible to differentiate all the three substances used. Predictions of percentage of WPC substitution were made through PLS regressions. The best prediction models were: lactose > creatine > caffeine. However, predictions resulted in overall good accuracy, low relative errors and coefficients of determination of fitting of calibration and validation curves above 0.97 in all cases. Therefore, techniques employed here aid the quality assessment of food products as alternative analytical tools.  


1984 ◽  
Vol 56 (3) ◽  
pp. 227-238
Author(s):  
Matti Näsi

In two digestibility and balance trials with growing pigs, whey protein concentrate (WPC) was compared as a protein supplement with casein (CAS) and dried skim milk (DSM), and, 30 % lactose (40 % dried whey, DW) was compared as a sugar supplement with the same amounts of hydrolysed lactose (HYLA) and sucrose (SUC). The effects of these supplements on protein and mineral metabolism of the pigs were investigated, WPC contained 42.2 % crude protein and had a high content of lysine, 8.6 g, and sulphur containing amino acids: cystine 2.8 and methionine 2.2g/16 g N, These exceeded the values for DSM. The hydrolysing degree of the enzymatically treated lactose syrup was 73 %. WPC had high crude protein digestibility, 99.1 % as compared to 95.4 for CAS and 95.0 % for DSM. Dried whey had low crude protein digestibility, 72.5 %. The amino acids in the WPC diet were highly digestible, but low values were obtained for the DW diet. On the WPC diet, nitrogen retention was higher than with the other protein supplements (P > 0.05), urinary urea excretion was low and the biological value very high. On a combination of WPC and HYLA protein utilisation was higher than on dried whole whey. On the diets supplemented with different sugars, none of the blood parameters differed statistically significantly (P > 0.05) and all values lay within the reference range. Water intake was on average 49 % greater on diets with sugar supplements than without. Urinary excretion of reducing sugars averaged 40.2, 8.3 and 6.6 g/d on the HYLA, SUC and DW diets, while on the diets without sugar supplements the values were 0.8—1.2 g/d. The following mean daily mineral retention values were obtained: P 4.0 g, Ca 5,9 g. Mg 0,4 g, Na 1.9g, K 2.9 g, Fe 27 mg, Cu 6.4 mg, Zn 65 mg and Mn 4.0 mg. The surplus Na and K on the DW diet were excreted in the urine and the pigs did not have diarrhoea.


2020 ◽  
Vol 2 (2) ◽  
pp. 77-85
Author(s):  
Slamet Hadi Kusumah ◽  
Robi Andoyo ◽  
Tita Rialita

Stunting children need food intake with higher protein and essential amino acids such as lysine and leucine than normal children. Red Beans (Phaseolus Vulgaris L.) and Green Beans (Phaseolus Radiatus L.) have protein content, respectively 22.07 ± 0.13% and 19.99 ± 0.07%, and are rich in essential amino acids lysine and leucine needed by a stunting child. The Development of food products with high protein concentrations (high protein food) such as isolates/protein concentrates is an important subject that must be done. This study aims to determine the technique of isolating red bean and green bean protein through extraction and deposition methods at isoelectric pH. The research method used is an experimental method with descriptive data analysis. Identification of isoelectric pH of red bean and green bean protein is done through electrophoretic mobility (cm2/Vs) testing on samples that have been conditioned at 3 different depositional pHs namely pH 3.00, 4.00, and 5.00. The results showed the isoelectric pH value of red bean and green bean protein, namely pH 4.56 and pH 4.81 respectively, where the pH had electrophoretic mobility values equal to zero. The process of isolating red bean and green bean protein produces protein powder with a protein content of 79.22 ± 0.06% and 80.69 ± 0.06%, respectively. Based on the weight yield, red bean and green bean protein concentrate powder had a yield of 14.88% and 16.75%, respectively.


Vestnik MGTU ◽  
2020 ◽  
Vol 23 (3) ◽  
pp. 205-213
Author(s):  
N. V. Linovskaya ◽  
E. V. Mazukabzova ◽  
O. S. Rudenko ◽  
T. V. Savenkova

Milk chocolate is particularly popular with different age groups. It is characterized by low protein content with a large amount of fats and carbohydrates determining the food imbalance of the product. In conditions of high-grade animal proteins deficiency the selection of high-quality protein-containing ingredients for food production is very relevant. The aim of this work is to study the protein adequacy of various components of milk chocolate to enhance its biological value. The amino acid scale method has been used to assess the biological value of proteins; it is based on the determination of amino acid (chemical) score. It has been found that the limiting biological value amino acid for classical white raw ingredients of milk chocolate (cocoa products and milk powder) is methionine + cysteine. For constructing chocolate formulas with increased biological value it is advisable to use protein-containing raw materials (whey protein concentrate, oat flour, etc.) to compensate for the limiting amino acids. The indicator of amino acids utilitarianity of proteins of raw milk chocolate components has been calculated. On the basis of the utilitarian index we have established the coefficient of utilitarian of the amino acid composition of the raw materials characterizing essential amino acids' balance. We have determined the biological value of protein and the amino acid composition imbalance coefficient. It has been found that the amino acid composition of milk and whey protein concentrates is most balanced compared to the amino acid composition of traditional protein-containing raw components of milk chocolate. The limiting acid of whey protein concentrate is valine, which makes its use in the manufacture of chocolate products more attractive compared to milk protein concentrate (the limiting amino acid is methionine + cysteine). In the group of vegetable non-conventional raw materials oat and buckwheat flour are characterized by the best indicators of biological value. The amino acid adequacy of oat flour is comparable to the qualitative protein indicators of cocoa products, the limiting amino acid is lysine. Buckwheat flour is characterized by the smallest imbalance in amino acid composition, which distinguishes the proteins of this raw material with the highest degree of digestibility compared with the proteins of all the studied protein-containing components of milk chocolate.


1971 ◽  
Vol 11 (53) ◽  
pp. 629 ◽  
Author(s):  
W Turner ◽  
CG Payne

Two experiments were conducted to investigate the usefulness of feeding layers diets based on high protein wheats. The test diets contained about 86 per cent of high protein wheat and were supplemented with various amino acids. A control diet contained wheat of normal protein content, soyabean and meat meal. In the first experiment lysine addition to the high protein wheat diet increased egg numbers ; and methionine supplementation, in addition to lysine, tended to further improve egg production. In the second experiment lysine addition again improved egg production, but, if inethionine was added as well, production fell. The varying response can be explained by different methionine contents of the two high protein wheats used.


2015 ◽  
Vol 27 (1) ◽  
pp. 105-114 ◽  
Author(s):  
R. Kubiczek ◽  
M. Rakowska

Total and soluble nitrogen, protein and non-protein -nitrogen was determined as well as the amino acid composition of the caryopses of ten rye varieties including three bred in Poland and cultivated on a commercial scale: 'Dańkowskie Złote', 'Dańkowskie Selekcyjne' and 'Borkowskie Tetra'. and seven foreign varieties characterized by a high total protein content (11.9-16.4% in dry weight). In the varieties examined the amount of protein nitrogen increased in the same degree as did the content of total nitrogen. The amino acids limiting the nutritive value of the protein in rye caryopses were mostly lysine and methionine, and in the varieties with high protein content tryptophan. The low-protein varieties had a relatively higher content of lysine, sulphur amino acids, tryptophan and other amino acids (as % of protein) than the high protein ones, but their absolute amino acid content (as % of dry weight) was lower.


2014 ◽  
Vol 34 ◽  
pp. 68-77 ◽  
Author(s):  
Dilek Sağlam ◽  
Paul Venema ◽  
Renko de Vries ◽  
Erik van der Linden

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 390
Author(s):  
Aleksandra Szydłowska ◽  
Dorota Zielińska ◽  
Anna Łepecka ◽  
Monika Trząskowska ◽  
Katarzyna Neffe-Skocińska ◽  
...  

The study aimed to develop the high-protein bars using organic ingredients such as whey protein concentrate (WPC), prebiotic-inulin, as well as pro-health additives (dried fruits, cereals, and nuts). The physicochemical, microbiological, sensory, and consumer evaluation of ingredients and final products were made. The musli (M), pumpkin (P), and coconut (C) bars were developed including three different flavors for each bar. The novel products were found to be a good source of protein and fiber. The M and P3 bar samples contained >10 g of fiber/100 g of product. The M and C bars contained over 20 g/100 g proteins in total, while P bars contained 17.3–19.1 g/100 g of protein. The antioxidant activity of bars was proportional to the fruit content. The water activity was varied (0.63–0.74), while pH value ranged from 6.3 to 7.0. Microbiological quality of ingredients and bars were good, though in M and P bars, the presence of Bacillus cereus was found. The C bars found the highest marks of the overall quality. The newly developed high-protein products can be used in rational nutrition of a wide group of people who are health-conscious.


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