Fresh Pleurotus nebrodensis was homogenized for use as an ingredient in the formulation of milk beverage. The effect of homogenization time on the particle size distribution of mushroom homogenate was investigated by a laser particle size analyzer. The formulation was optimized using response surface methodology. The independent variables were concentration and particle size of Pleurotus nebrodensis homogenate, composite stabilizer and skim milk powder. The stability of beverage was used as response variable. The composite stabilizer consisted of pectin, carboxy methyl cellulose (CMC) and monoglyceride with a ratio of 1.0:1.3:1.7 (m/m). Incorporation of 8% mushroom homogenate passing through a 100-mesh sieve, 0.3% composite stabilizer and 9% skim milk powder gave a homogenous product with a moderate sour and sweet taste and the best stability of (89.20 ± 0.41)%. Particle size analysis showed that the mean particle size of the beverage was (46.30 ± 0.51) μm and the particle size distribution was as follows: D (10)=11.78 μm, D (50) = 28.70 μm, and D (90) = 108.80 μm, which was significantly different from that of three commercial milk beverages. This beverage contained more protein ((2.46 ± 0.12)%) than commercial beverages and met the requirement of the national standard for milk beverage (GB/T 21732?2008). The beverage displayed both irregular particles and regular spherical particles with uniform size distribution and without particle aggregation as observed under microscopy and its particle size distribution was similar to that of commercial beverages.

Fermented okara with good processing suitability containing 13.4% soluble dietary fiber (SDF) was homogenized with a blender. After addition of other ingredients, the homogenate was formulated to produce a healthy high SDF milk beverage that was uniform and tasted good. Using one-factor-at-a-time method and response surface methodology, the optimum homogenization conditions were determined as follows: blender treatment time 15 min, blender rotation rate 10 000 r/min, stabilizer mixture 0.2%, temperature 45 ℃, pressure 30 MPa, and homogenization time 120 s, and the optimum combination of ingredients was fermented okara 7% (particles sieved through 60 mesh), white sugar 6%, and milk powder 9%. The milk beverage prepared under the optimized conditions had a good particle size distribution. Its soluble solids content was 11%, stability coefficient 0.8 and centrifugal sedimentation rate 2.3%. The product was milky white, and it was a uniform system with good taste and good stability.