Protein standardization of milk and dairy products

Rattray, W.; Jelen, P.

doi:10.1016/0924-2244(96)10024-8

Cited by 39 publications

(15 citation statements)

References 12 publications

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“…Protein is probably the most valuable constituent of milk, due to its high nutritional quality and unique physico-chemical and functional properties. These properties are fundamental to the production and characteristics of many dairy products, such as cheese or yogurt [19,35].…”

Section: Introductionmentioning

confidence: 99%

Impact of ultrasound on dairy spoilage microbes and milk components

Cameron

McMaster

Britz

2009

Dairy Sci. Technol.

132

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-Numerous reports in the literature suggest pasteurisation failures in the dairy industry as a possible cause for an end product with a poor quality. Ultrasonication offers the dairy industry a non-thermal alternative to pasteurisation. The aim of this study was to evaluate the use of ultrasonication as an alternative to heat pasteurisation. Ultrasound was found to eliminate spoilage and potential pathogens to zero or to levels acceptable by South African and British milk legislation, even when initial inoculum loads of 5× higher than permitted were present before treatment. Viable cell counts of E. coli were reduced by 100% after 10.0 min of ultrasonication. The data obtained also showed that viable counts of Pseudomonas fluorescens were reduced by 100% after 6.0 min and Listeria monocytogenes was reduced by 99% after 10.0 min. An infra-red based apparatus was used to analyse raw and pasteurised milk after an ultrasonic treatment. Ultrasonication did not lead to decreases in the protein or lactose content of both raw and pasteurised milk. Kjeldahl nitrogen determinations confirmed that ultrasonication had no detrimental effect on the total protein or casein content of pasteurised milk. This study indicated that ultrasonication lead to an increase in the fat concentration. This was explained by the larger surface area of the fat globules after ultrasonication, which led to an increase in light scattering as observed by the MilkoScan. Alkaline phosphatase and lactoperoxidase activities were also investigated as potential indicators of an effective ultrasonic treatment. Ultrasonication was, however, found to be ineffective in deactivating both enzymes used regularly by the dairy industry as indicators of effective thermal processes. Résumé -Impact des ultrasons sur les microbes d'altération du lait et sur ses composants.De nombreuses publications suggèrent que dans l'industrie laitière, la mauvaise qualité du produit fini peut provenir de défaillances de la pasteurisation. Le but de cette étude a été d'évaluer l'utilisation de l'ultrasonication comme alternative au traitement thermique. Les résultats ont montré que les ultrasons éliminaient totalement, ou à des niveaux acceptables par la législation sud-africaine et anglaise, la flore d'altération et les pathogènes potentiels, et ce même quand les charges d'inoculum initiales avant traitement étaient 5 fois supérieures à celles autorisées. La réduction du nombre de cellules viables après ultrasonication était de 100 % après 10.0 min pour E. coli, de 100 % après 6.0 min pour Pseudomonas fluorescens et de 99 % après 10.0 min pour Listeria monocytogenes. L'analyse par infrarouge du lait cru et du lait pasteurisé après traitement aux ultrasons ne montrait aucune diminution de la teneur en protéines et en lactose dans ces deux laits. La quantification de l'azote par Kjeldahl confirmait l'absence d'effet préjudiciable de l'ultrasonication sur les teneurs en protéines totales ou en caséines du lait pasteurisé. Cette étude montre que l'ultrasonication conduit à ...

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Section: Introductionmentioning

confidence: 99%

Impact of ultrasound on dairy spoilage microbes and milk components

Cameron

McMaster

Britz

2009

Dairy Sci. Technol.

132

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“…There is considerable international interest in standardizing the protein content of milk (Marshall, 1995;Rattray and Jelen, 1996a). Standardization of milk prote in 'upward' by ultrafiltration (UF) is advantageous in the manufacture of cheese and yoghurt, leading to improvements in product consistency, texture and yield (Maubois, 1991;Pu han, 1992).…”

Section: Introductionmentioning

confidence: 99%

Nutritional, sensory and physico-chemical characterization of protein-standardized UHT milk

Rattray

Gallmann

Jelen³

1997

Lait

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Summary -The protein content of 1.7% fat milk was standardized 'downwards' from -3.4% to values in the range -3.2-2.6%, by mixing with ultrafiltration (UF) permeate obtained from skim milk or quarg acid whey. Normal or protein-standardized milk products were subjected to direct (150 "C for 2.7 s) or indirect (138 "C for 1 s) ultra-high temperature (UHT) heat treatments and stored at 4 or 25 "C for up to 12 weeks. Standardization with skim milk permeate caused no change in the milk pH (6.7) and ail milk products had excellent stability during direct or indirect UHT heating. Upon storage at 4 or 25 "C for up to 12 weeks no age gelation occurred, and increases in apparent viscosity and sedimentation were minimal. Nutritional quality was slightly reduced by the addition of skim milk permeate, due mainly to minor decreases in the content of protein, calcium, phosphorus and potassium. Sensory quality was similar to normal UHT milk, as shown by periodic triangle sensory tests. The use of acid whey permeate for downward protein standardization led to a better profile of micronutrients, compared to milk with skim milk permeate. In other respects its use was unsatisfactory; although the pH shift upon addition of acid whey permeate to milk was minor (from pH 6.7 to pH 6.50-6.65), neutralization to pH 6.8 was required to avoid protein coagulation during direct or indirect UHT heating. In both direct or indirect UHT milk, high apparent viscosity and excessive sedimentation developed upon storage and off-flavours were unacceptably strong.protein standardization / URT milk / skim milk permeate / acid whey permeate Résumé -Caractérisation nutritive, sensorielle et physico-chimique de lait URT standardisé en protéine. La teneur en protéines du lait partiellement écrémé (1,7 % MG) a été standardisée à la baisse depuis -3,4 % à 3,2-2,6 % par addition de perméat provenant du traitement par ultrafiltration de lait écrémé ou de lactosérum obtenu lors de la fabrication de quarg. Les échantillons lactés ordinaires et standardisés en protéines ont subi un traitement ultra-haute température (UHT) selon une méthode de contact direct (2,7 s à 150 "C) ou indirect (15 s à 138 "C) avant d'être stockés pour une durée de 12 semaines à 4 "C ou 25 oc. La standardisation avec perméat de lait écrémé n'a produit aucun

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“…Possibilities of PMP combination of different membrane processes and integration with traditional techniques. 6 The nature, effects and volume of the emissions concerned.…”

Section: Discussionmentioning

confidence: 99%

“…UF used in protein standardization ensures the reduction of energy consumption. Employing UF in standardization of condensed milk and milk powder production has been improved at the 1995 Annual Sessions of the International Dairy Federation (Brussels) [6].…”

Section: Pmp In the Technologies Of Dairy Industry Productsmentioning

confidence: 99%