This study analyzed the proximate composition, amino acids, fatty acids, free sugars, organic acids, and mineral content of strong rice flour-based morning bread made with 0, 4, 8, and 12% (based on rice flour) of apple peel powder (APP). As the amount of APP increased, crude protein and crude fat decreased in the proximate composition of the morning bread, while dietary fiber increased. Also, the total amino acid content of the morning bread decreased. However, the ratio of glutamic acid and branched-chain amino acids did not change, and sulfur-containing amino acid content decreased. Further, the fatty acid composition showed a decrease in saturated fatty acids, and the unsaturated/saturated fatty acid ratio increased from 1.13 to 1.21. Additionally, fructose, glucose, and maltose increased, doubling the total sugar content. Oxalic acid and adipic acid decreased, while malic acid and acetic acid increased. Also, sodium (Na) decreased, potassium (K) and magnesium (Mg) increased, and the Na/K ratio improved from 3.5 to less than 2.0. Thus, it may be concluded that adding 8-12% APP to morning bread can be beneficial to health, as it is low in fat, high in dietary fiber, and high in minerals.
Lee et al. (Sat,) studied this question.