A Semimicro-Kjeldahl Method for the Determination of Total Nitrogen in Milk

Menefee, S.G.; Overman, O. R.

doi:10.3168/jds.s0022-0302(40)92829-6

Cited by 54 publications

(24 citation statements)

References 4 publications

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“…Protein content of skim milk, ultrafiltered milks and dahi were determined by semimicro Kjeldahl method described by Menefee and Overman (1940) using Kjeltec digestion (2300, Kjeltec Analyzer, FOSS) and laboratory distillation equipment followed by manual method. Total solids content of skim milk, ultrafiltered milks and dahi were determined by Gravimetric method as described by Indian standards (IS: 12,333-1997).…”

Section: Compositional Analysismentioning

confidence: 99%

Application of ultrafiltration technique for the quality improvement of dahi

et al. 2015

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Ultrafiltered milk (UF1 and UF2), ultrafiltrate retentate added milk (UF3 and UF4) and SMP added milk (UF0) were used for dahi preparation in the present study. Treatments were evaluated for rheological, textural and sensorial characteristics. Significant increase (p < 0.01) in values of firmness, stickiness, work of shear, work of adhesion and sensory scores, but significant decrease (p < 0.01) in whey syneresis values were observed with treatments UF1, UF2, UF3 and UF4 as compared to UF0. Principal component analysis (PCA) revealed that first four principal components (PC) explained 87.39 % relationship between samples and attributes. PC1 accounted for 48.34 % of data variance was characterized by protein content, firmness, work of shear, body & texture and opposed by total carbohydrates, stickiness, syneresis and work of adhesion. Total carbohydrates content (r = −0.982, P < 0.01), whey syneresis (r = −0.783, P < 0.01), stickiness (r = −0.729, P < 0.01) and work of adhesion (r = −0.684, P < 0.01) are negatively while body and texture (r = +0.600, P < 0.01), firmness (r = +0.574, P < 0.05) and work of shear (r = +0.538, P < 0.05) of dahi are highly positively correlated with protein content.

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Section: Compositional Analysismentioning

confidence: 99%

Application of ultrafiltration technique for the quality improvement of dahi

et al. 2015

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“…The 10.75 ml of diluted sample was measured into butyrometer of 10 % scale containing 10 ml of Gerber acid (BIS 2001). Total protein (Nx6.38) was estimated by semi micro-kjeldhal method as suggested by Meneffee and Overman (1940). Lactose was determined by the phenolsulphuric acid method as described by Lawrence (1968) and ash was determined gravimetrically as per the method of BIS (2001) for milk with slight modifications.…”

Section: Methodsmentioning

confidence: 99%

Manufacture of low lactose concentrated ultrafiltered-diafiltered retentate from buffalo milk and skim milk

Solanki

Gupta

2013

J Food Sci Technol

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Ultrafiltration (UF) is the most preferred method employed to extract milk protein used in the manufacture of milk protein concentrate in the dairy industry. It is also the most commonly used physical filtration process to remove lactose from milk. UF is an attractive process for reducing lactose from dairy products because it has molecular weight cut-off (MWCO) in the range of 1,000-5,00,000 Dalton. Therefore, lactose can easily pass through the membrane while retaining all the protein in the retentate. Limsawat and Pruksasri (2010) who studied the effect of process parameters transmembrane pressure and feed flow rate on permeate flux and rejections of protein and lactose in commercial low-fat UHT milk concluded that a high degree of removal of lactose from milk could be achieved by UF with a minimal or no lost of protein in permeate. Ultrafiltration membranes reject almost about 100 % lipids and proteins and all substances associated with them. Hence, their concentration in the retentate increases in proportion to the concentration factor. Since, the rejection of lactose by ultrafiltration membrane is virtually zero, almost all of its passes into permeate. Dushkova and Dinkov (2005) investigating the dry matter, protein and fat concentration factor and protein retention coefficient in retentates obtained by ultrafiltration of cow skim milk and cow milk standardized revealed that almost all protein substances casein and whey proteins are retained on the membranes, whereas only nonprotein soluble low molecular weight nitric compounds pass into the permeate. It is also evident that for standardized milk at the same volume reduction factors the fat concentration factor is approximately equal to the protein concentration factor. Patel and Mistry (1997) also reported that the rejection coefficients after 77 % weight reduction of UF buffalo skim milk were about 100 % for fat,~95 % for proteins and over 50 % for ash. The incomplete rejection of proteins might have been due in part to the distribution of pore sizes in the membrane and in part to the distribution of molecular mass among the milk proteins. Additionally, the method used for determining protein quantitated non-protein nitrogen (NPN) as well as true protein. Most of the NPN compounds of milk were small enough to permeate the membrane during UF. Over 50 % of the ash components were rejected by the membrane because most of the soluble minerals were able to permeate the membrane, and only those minerals that were in colloidal state and associated with proteins were retained by the membrane. Rejection rates for all the components were Electronic supplementary material The online version of this article

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“…For estimating the fat content of paneer samples by using cheese butyrometer, the method prescribed in IS: 1977: 1224 (Part II) was adopted. The protein content of paneer was determined by semimicro Kjeldahl method described by Manefee and Overman (1940) using Kjeltec digestion and distillation equipment (2300, Kjeltec Analyzer, FOSS) followed by manual distillation and titration method. Lactose content of samples was determined as per method described by Lawrence (1968).…”

Section: Physico-chemical Analysismentioning

confidence: 99%