, the surface application of HPMC significantly reduced fat content in the soy donuts (p < 0.05). SHC donut had the lowest fat content (25.13 g), followed by SH (26.63 g), and S (29.30 g), respectively. For moisture content (g moisture/100 g dough), all soy doughs had lower moisture content (14.04–15.73 g) than the wheat control (19.86 g). Marco and Rosell (2008) found similar results when part of the rice flour was replaced with soy proteins. However, after frying, soy donut had similar moisture content (10.93 g) as the wheat control (10.24 g). The incorporation of HPMC significantly increased the moisture content in soy SHC donut (p < 0.05). The moisture content of SH and SHC was 11.45 g and 12.48 g, respectively. While moisture content of all donuts decreased compared to that of dough, the moisture content of the wheat dough decreased by about 9% after frying, but HPMC added soy doughs decreased moisture by only 3–4% after frying. HPMC is the key ingredient for designing barrier films because of its gel forming properties at high temperature as well as its high water holding capacity ( Hamdy & White, 1969). The surface film could work as preventing the evaporation of water from product during frying processing. Adding HPMC combined with coating with HMPC seems to be a more effective way to retain water as well reduction in fat content during the frying process than only adding HPMC. For the caloric content from the health concerns, HPMC added donuts contain about 10% less calories due to higher moisture and lower fat content. In the case of soy donut without HPMC had about 6% less calories compare to wheat control.