Dry heat treatment of skim milk powder greatly improves the heat stability of recombined evaporated milk emulsions

1. Four Ayrshire bull calves between 8 and 34 days of age and fitted with duodenal and ileal re-entrant cannulas were used to study the effect of heat treatment of the milk they received on the pH and nitrogen composition of the pyloric outflow and ileal contents.2. Milk A contained a spray-dried skim-milk powder pre-heated during the drying process at 74° for 30 min and milk B a similar powder pre-heated at 77° for 15 sec. In milk A about 50% of the non-casein protein N had been denatured.3. Milk B resulted in a lower pH than milk A in the pyloric outflow throughout the sampling period of 6.5 h after feeding. It resulted also in an increased volume of outflow during the 1st h after feeding, a reduced output of undigested protein, an increased output of non-protein nitrogen (NPN) and a different pattern of flow of NPN during the first 4 h after feeding.4. These differences between milk A and milk B were associated largely with different clotting characteristics, which were demonstrated in vitro at two levels of addition of rennet with or without the addition of calcium. The buffering capacity of the two milks was similar.5. Variation between calves in their response to these two milks was attributed to the age of the calves and to differences in inherent clotting or proteolytic activity.6. In the ileal outflow, bacterial activity, as measured by dehydrogenase activity, was positively related to N concentration, but the N concentration when milk A was given did not appear to differ from that when milk B was given.7. One calf had diarrhoea when given milk A at a young age. This was associated with an increased pyloric outflow, an increased outflow of undigested protein but little difference in the rate of proteolysis, and a high pH. In the ileal outflow the volume and amount of N was much increased although the N concentration was reduced.8. It is concluded that the detrimental effect of milk A, found in earlier experiments, was largely associated with high pH and poor digestibility of protein in the abomasum, conditions which allow multiplication of coliform organisms in the intestine.

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Denaturation, aggregation and heat stability of milk protein during the manufacture of skim milk powder

Journal of Dairy Research ◽

10.1017/s002202990002985x ◽

1991 ◽

Vol 58 (3) ◽

pp. 269-283 ◽

Cited By ~ 74

Author(s):

Harjinder Singh ◽

Lawrence K. Creamer

Keyword(s):

Spray Drying ◽

Milk Powder ◽

Skim Milk ◽

Heat Stability ◽

Skim Milk Powder ◽

Casein Micelle ◽

Commercial Plant ◽

Preheat Treatment ◽

Solids Content ◽

Time Required

SummaryThe effect of preheat treatment, evaporation and drying in a commercial plant on the denaturation of βlactoglobulin and α-lactalbumin, their incorporation into the casein micelle and the heat stability characteristics of the milks and powders were determined. Preheat treatments between 110 °C for 2 min and 120 °C for 3 min denatured between 80 and 91% of β-lactoglobulin and between 33 and 45% of α-lactalbumin. Evaporation increased the extent of denaturation but spray drying did not increase it further. The incorporation of α-lactalbumin and βlactoglobulin into the micelles was markedly less than the amount that denatured and was not a constant ratio to it. Heat coagulation times at 140 °C of milks, concentrates and powders diluted to the original milk concentration were measured as a function of pH. In general, the greater the collective heat treatment, the shorter the time required to achieve coagulation. Spray drying shifted the peak positions in the pH-heat coagulation time profiles. In contrast, heat coagulation times (measured at 120 °C) of concentrates and powders diluted to 20% total solids content increased with the severity of the preheat treatment. Surprisingly, spray drying markedly increased the heat coagulation times of the diluted concentrates.

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Heat stability of recombined milk: influence of lecithins on the heat coagulation time-pH profile

Journal of Dairy Research ◽

10.1017/s0022029900030429 ◽

1992 ◽

Vol 59 (2) ◽

pp. 177-185 ◽

Cited By ~ 25

Author(s):

Catharina H. McCrae ◽

D. Donald Muir

Keyword(s):

Milk Powder ◽

Skim Milk ◽

Heat Stability ◽

Skim Milk Powder ◽

Coagulation Time ◽

Ph Profile ◽

Mineral Equilibria ◽

Soya Lecithin ◽

Before And After ◽

Wide Ph Range

SummaryTwo types of lecithin, namely egg and soya lecithin, were investigated as potential stabilizers of recombined milk. They were incorporated into recombined milk both before and after homogenization (20·7 MPa; 60 °C). Their presence at homogenization changed neither mineral equilibria nor homogenization efficiency. However, heat stability varied significantly irrespective of batch of low-heat skim milk powder used in recombined milk. The variation in heat stability depended on type of lecithin. Soya lecithin proved to be a very effective stabilizer. It improved heat stability over a wide pH range (6·3–7·1) and the effect occurred even when the lecithin was added after homogenization. In contrast, egg lecithin destabilized the system to heat at pH < 6·7 by converting a Type A into a Type B heat coagulation time-pH profile if it was incorporated before homogenization; after homogenization it had no effect. The effects of both egg and soya lecithin on the heat stability of recombined milk strongly suggest that interactions occur between phospholipids and milk protein.

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Improved heat stability of recombined filled evaporated milk emulsions by wet heat pre-treatment of skim milk powder dispersions at different pH values

LWT ◽

10.1016/j.lwt.2021.112739 ◽

2021 ◽

pp. 112739

Author(s):

Jianfeng Wu ◽

Simin Chen ◽

Lydivine Nyiransabimana ◽

Els J.M. Van Damme ◽

Bruno De Meulenaer ◽

...

Keyword(s):

Milk Powder ◽

Skim Milk ◽

Heat Stability ◽

Skim Milk Powder ◽

Ph Values ◽

Wet Heat ◽

Pre Treatment

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Effect of the milk heat treatment on properties of low-fat yogurt manufactured with microbial transglutaminase

Emirates Journal of Food and Agriculture ◽

10.9755/ejfa.2020.v32.i10.2180 ◽

2020 ◽

pp. 739

Author(s):

Belén García Gómez ◽

M Lourdes Vázquez Odériz ◽

Nieves Muñoz Ferreiro ◽

M Ángeles Romero Rodríguez ◽

Manuel Vázquez

Keyword(s):

Heat Treatment ◽

Starter Culture ◽

Milk Powder ◽

Skim Milk ◽

Textural Properties ◽

Skim Milk Powder ◽

Microbial Transglutaminase ◽

Sensory Profile ◽

Low Fat ◽

Positive Effect

The effect of milk heat treatment (UHT vs HTST) on physicochemical properties of low-fat set-style yogurt manufactured with microbial transglutaminase was evaluated. It was also evaluated the sensory profile of microbial transglutaminase yogurt and conventional fortified yogurt using skim milk powder. The UHT treatment of milk to make yogurts treated with microbial transglutaminase showed poorer texture results (firmness, consistency, cohesiveness and index of viscosity) than the HTST treatment of milk. Yogurt texture of UHT treatment was also worse than low-fat commercial yogurts, despite of the positive effect of the microbial transglutaminase. The microbial transglutaminase addition avoided the syneresis, regardless of the type of heat treatment. A microbial transglutaminase doses at low levels (0.76 U·g-1 of milk protein) added simultaneously with the starter culture was useful for improving the textural properties and sensory characteristics of low-fat yogurt, avoiding the normal syneresis of low-fat yogurt and without increasing the protein content that happen with the addition of skim milk powder. Yogurts made with microbial transglutaminase with HTST treatment showed significantly lower whey odor than yogurt fortified with skimmed milk powder. The application of microbial transglutaminase is a useful treatment for improving textural properties of low-fat yogurt with the usual pasteurization treatment applied in the dairy industry.

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