Characterization of whey protein isolate obtained from milk microfiltration permeate

Abstract

Whey protein was concentrated from milk microfiltration permeate or Cheddar cheese whey using batch ultrafiltration and diafiltration. Permeate flux declined more rapidly for milk microfiltrate during concentration, but similar flux profiles were observed on both wheys during diafiltration. Protein contents in concentrates from milk microfiltrate and cheese wheys were respectively 95 and 74% on a dry matter basis, while their fat contents were respectively 0.2 and 15%. Protein solubility of the milk microfiltrate isolate was over 95% between pH 3 and 8, while protein solubility of cheese whey concentrate varied between 75 and 90% over the same pH range. J3-Lactoglobulin in cheese whey concentrate showed ex1ensive structural alteration as evidenced by the low proportion of SH groups in native position. J3-Lactoglobulin structural alteration was less severe in protein isolated from milk microfiltrate, but still significant. Milk microfiltrate protein isolate showed better gelling properties th an cheese whey protein concentrate. Cheese whey protein concentrate did not foam at ail, while stiff and stable foams were produced from milk microfiltrate protein isolate. Gelation and foaming were very sensitive to the ionic environment and were controlled by a balance between the pH and the calcium concentration. Reduction of calcium content in milk microfiltrate protein isolate, using saline solution during diafiltration, had only slight effects of protein functional properties. milk microfiltration / whey protein 1 ultrafiltration / heat set gelation / foaming property Résumé -Caractérisation d'un isolat protéique de lactosérum obtenu à partir d'un perméat de microfiltration de lait. Les protéines d'un perméat de microfiltration de lait et d'un lactosérum de fromage Cheddar ont été concentrées par ultrafiltration en batch suivie d'une dia filtration. La comparaison des flux de microfiltration indique un colmatage plus rapide pendant la concentration du microfiltrat de lait. Les flux de perméation en fin de concentration et pendant la dia filtration étaient toutefois similaires. Les teneurs en protéines des concentrés protéiques de micro filtrat de lait et de lactosérum fromager étaient respectivement de 95 et 74%, alors que les concentrations lipidiques atteignaient respectivement 0,2 et 15,5 %. La solubilité des isolats de microfiltrat de lait était supérieure à 95 % entre pH 3 et 8, alors que la solubilité des concentrés de lactosérum fromager variait de 75 à 90 % sur la même fourchette de pH. La structure native de la J3-lactoglobuline, évaluée par la position du groupement SH libre, était fortement altérée dans le concentré de lactosérum fromager. L'altération structurale de la J3-lactoglobuline était moins importante dans J'isolat de microfiltrat de lait, mais toutefois significative. Les propriétés thermogélifiantes de J'isolat de micro filtrat de lait étaient supérieures à celles du concentré de lactosérum fromager. L'isolat de microfiltrat de lait formait des 256 M Britten, Y Pouliot mousses fermes et stables alo...

Processing Foods Free from Dairy Proteins

“…CN, the major milk protein, is heat stable [10] and makes milk protein ingredients well adapted for cooking applications. At neutral pH, the solubility of low -heat skim milk powders and protein concentrates is higher than 95% [13] . In coprecipitates, serum protein denaturation is responsible for poor solubility.…”

“…Milk protein concentrates or isolates processed this way, with protein concentrations ranging from 50% to 90%, are available to food processors. In some instances, larger pore size membranes (microfi ltration) can also be used to remove a portion of soluble protein [13] . Concentrates obtained by microfi ltration, therefore, contain higher concentration of micellar CN.…”

Review on Membrane Technology Applications in Food and Dairy Processing

“…The casein fraction can be used for vatless (e.g., no need of tank for cutting and washing the curd) production of semi-hard and hard cheeses or for production of casein-enriched ingredients without using acids to precipitate caseins and then other chemicals to neutralize the products [40][41][42]. The volume of the retentate from the MF is much lower than that of the original milk and that the production of cheese from the retentate requires less quantity of rennet and additives, reduces total production time, increases capacity of the plant.…”

“…The 0.1-0.2μm MF permeate (microfiltrate), considered as sweet whey, contains the major whey proteins in highly functional (undenatured) state. Compared to classic cheese whey, the microfiltrate contains no rennet, bacteria, and starter culture, contains extremely low lipid content (i.e., <0.01%) and is more consistent in composition among production batches and different companies [41]. This whey can be directly (without the necessity of clarification steps as for the whey from normal cheese making process) subjected to UF for manufacture of functionality-enhanced whey protein concentrate (WPC) and whey proteins isolate (WPI).…”

“…This whey can be directly (without the necessity of clarification steps as for the whey from normal cheese making process) subjected to UF for manufacture of functionality-enhanced whey protein concentrate (WPC) and whey proteins isolate (WPI). The obtained powders have better oxidation stability due to a low concentration of lipids and has better technological properties e.g., gelling and foaming properties [41,43].…”