Ultrasonication of reconstituted whole milk and its effect on acid gelation.
Ultrasonication (US) of whole milk at 22.5kHz and 50W homogenized fat globules. Extended US without temperature control (attaining >90°C at longest times), or with control at temperatures ⩾60°C caused denaturation of the whey proteins and aggregation of the fat globules and proteins. Acidification of US milk produced gels with increased firmness and reduced gelation times compared to untreated milk. Below 60°C, US of milk produced acid gels with very high firmness without whey protein denaturation; the firmness was similar to gels from heated whole milk. Extensive US without temperature control or with control at ⩾60°C decreased acid gel firmness compared to shorter times or lower temperatures. Higher acid gel firmness could be achieved by subjecting the milk to separate heat (80°C/30min) and US treatment (at 20°C) before acidification when compared with either heating or US alone. This was independent of the order of heating and US treatment.
Fonterra Research and Development Centre, Private Bag 11029, Dairy Farm Road, Palmerston North, New Zealand.
Nguyen H A
NHA
Nguyen
Fonterra Research and Development Centre, Private Bag 11029, Dairy Farm Road, Palmerston North, New Zealand. Electronic address: skelte.anema@fonterra.com.
Skelte G
SG
Anema
D000818:Animals; D004041:Dietary Fats / Q000032:analysis; D005511:Food Handling; D005782:Gels / Q000737:chemistry*; D006358:Hot Temperature; D008892:Milk / Q000737:chemistry*; D010316:Particle Size; D011489:Protein Denaturation; D012212:Rheology; D014465:Ultrasonics; D000067816:Whey Proteins / Q000032:analysis
D004041:Dietary Fats; D005782:Gels; D000067816:Whey Proteins
Acid gels; Denaturation; Particle size; Rheology; Ultrasonication; Whole milk