Demand is increasing for high-protein baked goods. Soy protein isolate (SPI) is a complete, plant-based protein that may be added to baked goods such as muffins to develop a high-protein snack. In preliminary testing, muf-fins made with 10-40% soy protein isolate had a thick batter, gummy texture, and 10% soy protein isolate were preferred, while 20% addition of soy protein resulted in an undesirable beany flavor. SPI can be modified through enzymatic hydrolysis to cleave peptide bonds at specific locations, which has been shown to improve functional (solubility, foaming, emulsifying) and organoleptic properties of SPI in model systems. However, few studies in-vestigate these properties in food matrices. The objective of this study was to understand the effect of enzymat-ic hydrolysis on functionality of soy protein isolate in muffins. Two soy protein hydrolysates were prepared using two enzymes: 1) Flavourzyme®(a commercial enzyme blend of endo-and exopeptidases) and 2) papain. Seven muffin treatments were prepared (n= 3) with three protein types (SPI, commercial blend soy hydrolysate (FSH), papain soy hydrolysate (PSH)) at two levels (10% and 20% flour weight basis) and a control with no protein (C). Batter tests included specific gravity and pH. Muffin tests included crust and crumb color, height, weight, texture profile analysis, water activity, and moisture loss. Visual observation of batter during mixing found SPI batters (SPI10 and SPI20) increased in viscosity as protein level increased. Hydrolysate batters (FSH10, FSH20, PSH10, and PSH20) were more like control in viscosity. Specific gravity ranged from 0.95-1.08 with SPI10, SPI20, and CBSH20 having lower (p< 0.05) specific gravity values than C. Batter pH ranged from 6.53-7.72 and no significant differ-ences were found. No significant difference was found for crust lightness (70.86-74.49), crumb lightness (72.73-74.77), weight (68.2-72.1 g), hardness (6.85-11.17 N), water activity (0.500-0.580) or moisture loss (11.1-12.7%). Muffin height ranged from 41.7-46.7 mm and all treatment heights were like control, however, PSH10 and SPI20 were significantly different from each other with heights of 41.7 mm and 46.7 mm, respectively. Overall, hydroly-sis of SPI resulted in batters more like control than SPI and did not reduce physical quality as compared to C. Sim-ilarity of hydrolysate treatments to control indicates higher protein levels than those evaluated may be achieved with the use of hydrolysates as compared to SPI. Further studies are needed to explore the effects of higher lev-els of soy protein hydrolysates on physical and sensory properties of baked goods