Rheological Properties and Microstructure of Acid Milk Gels as Affected by Fat Content and Heat Treatment |
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Authors: | J. A. LUCEY P. A. MUNRO H. SINGH |
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Affiliation: | Authors Lucey, Munro, and Singh are with the Inst. for Food, Nutrition and Human Health, Massey Univ., Palmerston North, New Zealand. |
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Abstract: | Gels were made from recombined milks containing 0, 1.5 or 3.5% fat that were heated at 75, 80 or 90°C for 30 min, followed by acidification with glucono-8-lactone at 30°C. The rheological and microstructural properties of acid gels were investigated using dynamic low-amplitude oscillatory rheology and confocal scanning laser microscopy (CSLM). Heating milks, at temperatures ≥80°C, increased the storage moduli (G′) and decreased the gelation time. Recombined milks containing high fat (3.5%) had higher G′ than gels made from low-fat or skim milk. Milk heat treatment resulted in gels with a cross-linked microstructure. Recombined fat globules appeared to be embedded in the protein matrix. |
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Keywords: | homogenization microstructure rheology acid milk gelation |
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