Industrial application of sesame by-product: optimization of incorporation ratio into halva using response surface methodology

The industrial waste from sesame paste production (sesame seeds coat) is a valuable source of dietary fiber that could be used as a functional food ingredient. However, its high water activity (~ 0.98) makes it susceptible to microbiological contamination and rapid spoilage. This study addresses this issue by proposing microwave drying of the wet sesame by-product to reduce its water activity, followed by incorporating the dried sesame biomass into halva formulation to create a value-added product. Response surface methodology (RSM) was used to optimize the amount of sesame biomass and emulsifier in the formulation and quadratic models were developed for ten responses (stability, whitening index, taste, smell, color, ease of cutting, mouthfeel, friability, oiliness, and overall acceptance). The optimization results suggested incorporating 1% dried sesame coat and 3% emulsifier per kilogram of sesame paste, based on the evaluation of emulsion stability, texture, color, and sensory properties. Compared to the negative control without any additives (sample 1), this optimal formulation (sample 8) improved emulsion stability from 1.44 to 0.55% and hardness from 5.65 N to 68.93 N. Compared to the positive control with only emulsifier (sample 3), the addition of dried sesame coat and emulsifier had no significant effect on sensory properties, while enhancing nutritional value by increasing fiber content. Therefore, we recommend determining the fiber content of halva as further analyses to ensure that our product truly deserves the label “halva enriched with sesame fibers.”