| Rice bran oil (RBO) has been shown to reduce oxidation of whole milk powder (WMP) and the accumulation of oxidation products. The objectives of this study were to determine the threshold value of high-oryzanol (6%) RBO in reconstituted WMP, identify the flavor profile of stored WMP with added RBO, and determine consumer acceptance of RBO fortified WMP as a food ingredient. RBO was added to WMP at concentrations of 0.25, 0.51, 1.01, 2.02, 4.05, and 8.10% (w/w) of the original milk for the threshold test. WMP treated with 0.5% RBO (w/w) was stored at 45°C for 40 days to accelerate oxidation. Descriptive analysis, gas chromatography olfactometry (GCO), and gas chromatography-mass spectrometry (GC-MS) were performed on Day 0, 20, and 40. The effect of RBO fortified WMP on the flavor and consumer preference of fresh baked potato bread was evaluated. The best-estimate threshold for RBO in WMP was 3.28%. The addition of RBO at the lower concentrations did not have an objectionable effect on the milk's flavor, viscosity, or texture. The addition of RBO at 0.5% w/w had no effect on the sensory properties of WMP (p < 0.05). Significant changes in flavor attributes occurred in both WMP samples (p < 0.05); however, the highest increase in flavor intensity appeared in the painty/oxidized attribute. This was seen in the control sample after 40 days (p < 0.05). Volatile profile changes also occurred with storage time, but were not different between control and RBO-treated WMP. Yeast-raised potato breads made from RBO-treated WMP (40 days at 45°C) received the highest scores for aroma liking, flavor liking, appearance liking, and overall acceptance (p < 0.05). Results indicated that RBO (added to WMP at 0.5% w/w) improved the oxidative stability of the WMP without affecting the sensory or functionality. |
