Researchers from Pakistan’s Government College University Faisalabad conducted a study to determine whether okara, a by-product of soybean processing that is often discarded as waste, could be used to enhance the nutritional value of dairy ice cream. Okara, which contains significant amounts of dietary fiber, protein, lipids, vitamins, and minerals, also has prebiotic properties. By incorporating okara into dairy ice cream fortified with probiotic bacteria, the researchers aimed to create a functional dessert that is low in fat, high in protein, and appealing to consumers seeking functional dairy products. This innovation could also potentially reduce agricultural waste from soybean processing.
To assess how the inclusion of okara affects the properties of dairy ice cream, the researchers divided a batch of ice cream into four samples. Three of these samples were fortified with different concentrations of okara (1%, 2%, and 3%), while the fourth sample served as a control and did not contain okara but did include probiotic L. rhamnosus GG. Through a series of experiments, the researchers measured various properties of the ice cream, including nutritional content (such as fat, fiber, and protein), functional properties (such as meltability and viscosity), and the viability of probiotic bacteria.
The study revealed that adding 1% of okara resulted in the greatest reduction in fat content, likely due to the high concentration of insoluble fiber in okara, which aids in fat absorption. The protein content of the okara-fortified samples was higher than that of the control sample, with the 3% batch containing the highest protein levels. Additionally, the fortified samples exhibited a slower melting rate compared to the non-fortified sample, suggesting that the presence of okara reduced the overrun and thus the melting rate.
During storage, the ice creams containing okara maintained higher probiotic counts and a stable number of probiotics compared to the control sample. The 3% batch demonstrated the highest amount of viable bacteria, potentially attributed to its higher protein concentrations.
While okara enhanced the nutritional profile of the ice creams, consumer sensory evaluation was necessary to assess its acceptability. A group of 40 consumers evaluated the samples based on texture, taste, color, and overall acceptability. Surprisingly, the 1% okara sample received the highest acceptability score, while the control sample was favored for its taste, texture, and color properties. The 2% and 3% samples received lower scores, with the ice cream containing the highest amount of okara being the least popular due to its sandy texture.
In conclusion, the researchers determined that the addition of okara significantly influenced the sensory attributes and physicochemical properties of the ice cream. However, they highlighted the ingredient’s key role in supporting probiotic viability.
Source:
“Characterization and valorization of soybean residue (okara) for the development of synbiotic ice cream”
Afzaal, M., et al
Published: 07 August 2023, Wiley
DOI: 10.1002/fsn3.3606