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A comparison of selected quality characteristics of yoghurts prepared from thermosonicated and conventionally heated milks

Riener, Joerg, Noci, Francesco, Cronin, Denis A., Morgan, Desmond J., Lyng, James G.
Food chemistry 2010 v.119 no.3 pp. 1108-1113
yogurt, heat treatment, food processing, food processing quality, ultrasonic treatment, rheological properties, temperature, texture, milk fat percentage, gel strength, gelling properties, water holding capacity, retrogradation, food nutrient losses, thiamin, riboflavin, tocopherols, sensory properties, vitamin A
Thermosonication (TS) of preheated (45°C) milk (0.1%, 1.5% and 3.5% fat) for 10min at an ultrasound frequency of 24kHz allowed the preparation of yoghurts with rheological properties superior to those of control yoghurts produced from conventionally heated milk (90°C for 10min). Texture profile analysis and flow curves showed that yoghurts from the TS milks had stronger gel structures which displayed higher water-holding capacities (WHC) and lower syneresis. Based on averaged data from a sensory panel (n =30), TS yoghurts showed superior texture and colour properties and samples with a fat content of 0.1% scored best in terms of overall acceptability. Retentions of water-soluble (thiamine and riboflavin) and fat-soluble (retinol and tocopherol) vitamins were similar in TS and conventionally prepared yoghurts.