Consumers demand of non-fat yogurt has increased. To improve the textural and/or increase functional properties of yogurt, the addition of some ingredients or changes in the process are alternatives. The objective was to investigate the effect of concentration of protein (PTN) and of transglutaminase enzyme (TgE), and rotational speed centrifuge (CRS) on the physical-chemical parameters of non-fat yogurt. The experiment followed the Box Behnken (DBB) design with three factors: CRS (3000, 4250 and 5500 rpm), PTN (3.4, 4.9 and 6.4% p/v) and TgE (0, 1 and 2 U/g of protein). The processing of yogurts started with the mixing of reconstituted skimmed-milk powder (3.4% of PTN) and sugar (10%) and heating at 83 ºC/30 min. Other PTN concentrations were obtained by complementing the initial concentration with casein. Addition of TgE was performed to 40 ºC/90 min. Enzyme deactivation was conducted to 80 ºC/2 min. The mixture was then cooled to 43 ºC and 1% lactic cultures was added. After fermentation, the yogurt was refrigerated at 8 ºC. To obtain a concentrated yogurt, the yogurt was centrifugated (3000, 4250 or 5500 rpm) at 10 ºC/5 min. The product was kept at 8 °C in plastic bottles. The pH, acidity and protein determination followed methodology according Normative Instruction nº30. Water activity (aw) was performed in AquaLab series 4TE. Volume of partial whey syneresis by centrifugation (VPWS) was measured in a graduated cylinder. The results were analyzed by ANOVA and Pearson's correlation (α=0.05). No significant differences were found between the formulations (p>0.05) in relation to pH, acidity, and aw. The values acidity, pH, and aw varied between 0.6 a 1.5 g/ 100g de acid lactic, 4.4 – 4.6, and 0.985 and 0.990, respectively. The final protein content ranged from 2.7 to 7.5%. Three formulation presented protein levels greater than 5.6% and can be considered concentrated fermented milk. VPWS was positively correlated with the final protein content (0.584, p<0.05), regardless of the concentration of added casein. Modifications in yogurt formulation and process condition prompted changes in final protein level. Non-fat yogurt with high level of protein has been developed which contributes to its greater healthiness.