ABSTRACT This study investigated the impact of storing two soybean varieties (SC Semeki and Uyole Soya 2) in polypropylene and PICS bags at 15°C and 25°C, with analyses at 30‐day intervals for 3 months, on the retention of their protein content, amino acid profiles, and the functional properties of their protein isolates. The study indicates that using polypropylene bags at 25°C was not effective in maintaining the nutritive quality during storage. This led to a decrease in protein content of 3.85% and 5.19% and a decrease in PS of 12.47% and 7.32% in SC Semeki and Uyole soya 2, respectively. In contrast, similar settings led to an increase of emulsifying capacity by 40% and 41% and oil absorption capacity by 18% and 28% in SC Semeki and Uyole Soya 2, respectively. On the other hand, results from amino acid analysis indicated a higher retention in amino acids with the use of PICS bags (12/17) compared to polypropylene bags (3/17). Similarly, majority of amino acids were retained better at 15°C (6/17) compared to 25°C (2/17). Therefore, the use of PICS bags at low temperatures (15°C) is highly recommended for preserving nutritional quality and functional properties of SPI in comparison.
Msuya et al. (2026) studied this question.