Effects of added salts on the heat stability of recombined concentrated milk

Augustin, Mary-Ann; Clarke, P. T.

doi:10.1017/s0022029900026820

Cited by 51 publications

(44 citation statements)

References 24 publications

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“…This is in agreement with earlier reports that showed that a seasonal increase in the ratio of calcium to orthophosphate could be correlated with a reduction in heat stability [30]. Lowering free calcium ion activity through the addition of calcium sequestering agents has also been shown to improve the heat stability of preheated milk powders [6]. In our experiments we have seen that additional factors linked to the stability of the micelles and the aggregation states of the proteins may also be involved.…”

Section: Soluble Aggregate Compositionsupporting

confidence: 93%

“…In this case, it appears that reducing the mineral content through lactose standardization has reduced the degree of aggregation. This has parallels with earlier work [6] where heat stability could be improved by reducing calcium ion activity. Figure 2 shows the profiles for the milk powders produced in trial 1.…”

Section: Change In the Size Distributionssupporting

confidence: 75%

“…Altering the environment of the milk proteins may also influence both the heat stability of standardized milk powders and the formation of soluble aggregates through effects on either protein denaturation or micellar integrity. In addition, milk production systems which are predominantly pasture based, as occurs in Australia, can also be subject to seasonal effects which can affect the heat stability of milk [6,40] and it is not known how these seasonal effects interact with standardization practices. The aim of the following work was to investigate the effects of standardization on both heat stability, soluble aggregate formation, and the effects of seasonal variation.…”

Section: Introductionmentioning

confidence: 99%

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Role of protein aggregation in heat-induced heat stability during milk powder manufacture

Williams

D'ath

Zisu

2008

Dairy Sci. Technol.

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-Although the inherent heat stability and the processes leading to the heat-induced coagulation of milk and reconstituted milk powders have been studied extensively, the processes that lead to heat-induced heat stability are less well established. An investigation has been undertaken into the effects of standardization with milk permeate or lactose and the heat-stabilization of milk powders. Standardized and unstandardized milk powders were produced in spring and autumn to determine seasonal effects on their heat stability. Other standardized powders were produced using a range of preheat treatments (85 • C/1800 s, 120 • C/120 s, and 140 • C/5 s) to evaluate the effects of preheat treatment and standardization on the heat stability of milk powders. Micelle size and the soluble aggregates formed during the preheat treatment were characterized by a combination of size-exclusion chromatography and SDS-PAGE. The heat stability of the powders was evaluated in a bench-scale model of retorted recombined evaporated milk manufacture. As has been generally accepted, the heat stability may be mediated by the way in which the milk responds to the preheat treatment given during milk powder manufacture. However, we have found that causing the denaturation of the whey proteins in itself, as is indicated by analytical measures such as the whey protein nitrogen index (WPNI) is not sufficient to impart heat stability. Our work suggests that milks with good heat stability are achieved by heating to give a low WPNI and a balance of moderately sized soluble aggregates and a decrease in the proportion of smaller micelles. The formation of these aggregates is influenced by the heating regime applied and varies at different times of year.heat stability / milk protein aggregation / micellar integrity Résumé -Rôle de l'agrégation des protéines dans la stabilité thermique thermo-induite au cours de la fabrication de poudre de lait. Bien que la stabilité thermique inhérente et les processus conduisant à la coagulation thermo-induite du lait et des poudres de lait reconstituées aient été largement étudiés, les processus qui conduisent à la stabilité thermique thermo-induite sont moins bien établis. Une étude a été entreprise concernant les effets de la standardisation avec du perméat de lait ou du lactose et la stabilisation thermique des poudres de lait. Des poudres de lait, standardisé et non standardisé, ont été produites au printemps et en automne pour déterminer l'effet saison sur leur stabilité thermique. D'autres poudres standardisées ont été produites en appliquant différents prétraitements thermiques (85 • C/1800 s, 120 • C/120 s et 140 • C/5 s) pour évaluer les effets du pré-traitement et de la standardisation sur la stabilité thermique des poudres de lait. La taille des micelles et les agrégats solubles formés au cours du prétraitement thermique ont été caractérisés en combinant chromatographie d'exclusion de taille et électrophorèse SDS-PAGE. La stabilité thermique des poudres était évaluée à l'aide d'un modèle simulant...

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Section: Soluble Aggregate Compositionsupporting

confidence: 93%

Section: Change In the Size Distributionssupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

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Role of protein aggregation in heat-induced heat stability during milk powder manufacture

Williams

D'ath

Zisu

2008

Dairy Sci. Technol.

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“…Calcium and phosphorus migrate from the micelle and calcium phosphate becomes more soluble. This results in increase of free ionic calcium, causing liberation of hydrogen ions and decrease in pH (Augustin & Clarke, 1990). The distribution of caseins and calcium between the serum and micellar phase is pH and temperature dependent.…”

Section: The Effect Of Ph Reduction On Gelation Of Uht Milk At 25 °Cmentioning

confidence: 99%

Preliminary Study on the Role of Ionic Calcium in Gelation and Proteolysis of UHT Milk

Mlipano

Michael²

2017

JFS

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A study was conducted to determine the influence of ionic calcium on gelation and proteolysis in milk. Raw milk was heated to 142 °C for 2s followed by cooling to 5 °C to make UHT milk. Two sequestering agents, Trisodium citrate (TSC) and Sodium hexametaphosphate (SHMP) were added at 0.04 -0.08% (w/v) to the processed UHT milk to reduce the ionic calcium levels. Proteolysis and gelation were induced by addition of trypsin (248 BAEE units), 0.03% (v/v) chymosin and 10 6 cfu/mL Pseudomonas fluorescens NCIMB 702085 (Ps. fl. 416) to UHT milk. Samples were stored at 25 °C for 2½ weeks to monitor gelation and Ca 2+ and some were incubated at 37 °C for 2h to monitor proteolysis. SHMP reduced more Ca 2+ than TSC. Ca 2+ reduction was accompanied by an increase in pH, most evident with TSC at 25 °C. Gelation was not observed in samples inoculated with Ps. fl. 416 (with sequestering agents) even after 9 days of storage, suggesting the importance of calcium in gelation. Chymosin treated samples gelled on day 0, whereas other samples gelled after 4 days. Trypsin increased Ca 2+ to levels higher than originally present in control UHT skim milk. Although in the current study, proteolysis was higher in samples inoculated with Pseudomonas fluorescens 416, no clear relationship was established between proteolysis and gelation in UHT milk. This observation Journal of Food Studies

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“…Generally the addition of calcium salts to milk causes an increase in serum calcium ions, an increase in calcium in the colloidal phase, a decrease in pH, and a decrease in heat stability. Reduction of the calcium ion concentration by the addition of phosphate or citrate generally causes an increase in heat stability [1,23].…”

Section: Introductionmentioning

confidence: 99%

Production of calcium-fortified milk powders using soluble calcium salts

Williams

D'ath

Augustin

2005

Lait

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-The choice of appropriate calcium salts for fortification of milk or milk powders is a challenge for the dairy industry. Depending on the form of salt used, the addition of calcium to dairy products has the potential to influence the colour, texture, stability, flavour, and processing characteristics of the final product. A novel strategy was developed for the calcium fortification of liquid milk and calcium-fortified milk powders, based on results obtained in liquid milk systems. The process involves adding a combination of orthophosphates with a soluble calcium salt (calcium chloride) to milk, subjecting the milk to low-heat (72 °C/30 s) or high-heat (90 °C/10 min) treatment, concentrating the milk to approximately 450 g total solids·kg -1 and spray drying the concentrate to produce powders with approximately 50 g·kg -1 moisture. Calcium-fortified skim and milk powders with up to an extra 8 g of calcium per kg of powder were prepared. These powders were easily reconstituted in water to give skim milk solutions (100 g total solids·kg -1 ) with a total calcium content of between 2000 and 2300 mg Ca·L -1 . The total concentration of calcium in the fortified powder depends on the level of calcium in the base milk from which it is produced. Recovery rates of at least 97% were obtained in the final powders. This strategy can be used for the production of both high-heat and low-heat milk powders with increased calcium levels. milk powder / fortification / calcium / heat stability Résumé -Production de laits en poudre enrichis en calcium par l'emploi de sels de calcium solubles. Le choix de sels de calcium pour l'enrichissement du lait ou de laits en poudre représente un défi pour l'industrie laitière. Selon la forme du sel qui est utilisé, l'addition de calcium aux produits laitiers a le potentiel d'influencer la couleur, la texture, la stabilité, l'arôme et les caractéristi-ques de fabrication du produit final. Une nouvelle stratégie a été développée pour l'enrichissement en calcium du lait liquide et des laits en poudre, basée sur les résultats obtenus dans les systèmes de lait liquide. La technique implique l'addition au lait d'une combinaison d'orthophosphates et d'un sel soluble de calcium (chlorure de calcium) puis un traitement thermique à basse (30 s à 72 °C) ou haute (10 min à 90 °C) température ; le lait est ensuite concentré jusqu'à un extrait sec de 450 g·kg -1 puis déshydraté par atomisation pour obtenir des poudres à 5 % d'humidité. On a pu ainsi préparé des laits en poudre écrémés enrichis en calcium de 8 g par kg de poudre. Ces laits en poudre étaient facilement reconstitués sous forme liquide pour donner des laits reconstitués écrémés à 100 g d'extrait sec par kg avec des teneurs en calcium comprises entre 2000 et 2300 mg par litre. La concentration totale de calcium dans le lait en poudre enrichi dépend du niveau de calcium dans le lait de base à partir duquel il est produit. Des taux de récupération d'au moins 97 % ont été obtenus dans les poudres finales. Cette stratégie peut être utilis...

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Effects of added salts on the heat stability of recombined concentrated milk

Cited by 51 publications

References 24 publications

Role of protein aggregation in heat-induced heat stability during milk powder manufacture

Role of protein aggregation in heat-induced heat stability during milk powder manufacture

Preliminary Study on the Role of Ionic Calcium in Gelation and Proteolysis of UHT Milk

Production of calcium-fortified milk powders using soluble calcium salts

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