Phytochemicals, such as sulforaphane, that have the potential to maintain or improve performance of the warfighter are of interest to the military. Sulforaphane, a hydrolysis product of glucoraphanin, is specifically of interest because it is an indirect antioxidant that induces Phase 2 detoxification enzymes. However, retained efficacy after long-term storage [3years at 80oF; military required shelf life] is unknown. The stability of glucoraphanin was assessed in three model systems, a macronutrient balanced bar and bread roll at two pH levels [≤4 and ≥5.5] and an energy gel [pH 4]. Individual samples were formulated with 400mg of broccoli powder containing 52.1mg of glucoraphanin. Accelerated storage studies were conducted to assess glucoraphanin stability at 120oF for 4 weeks and 100oF for 6 months. Extraction and analytical quantification of sulforaphane was conducted to determine losses in glucoraphanin due to storage. Prior to enzymatic hydrolysis, bar and bread samples were defatted with hexane. For extraction, a portion of each product (containing ~20mg of broccoli powder) was hydrolyzed for two hours with thioglucosidase plus co-factors (ascorbic acid and magnesium chloride) in a potassium phosphate buffer solution (pH=6.5). Sulforaphane was extracted from the buffer with methylene chloride [3xs], which was then evaporated to dryness at 35oC. Reconstituted extracts were quantified using HPLC-UV detection at 254nm. For the macronutrient balanced bars (low and high pH), 95-100% of supplemented glucoraphanin (measured as sulforaphane) was retained throughout both storage studies. The energy gel contained 102% of expected glucoraphanin before storage, while the high and low pH breads contained only 45 and 0% respectively. However, by the end of both storage studies, there was 0% glucoraphanin remaining in either the energy gel or high/low pH bread models. In future studies, broccoli powder will be incorporated into prototype food bars, and tested for sensory attributes and stability over storage.

Assessing the stability of glucoraphanin [by measurement of sulforaphane] in model food systems supplemented with broccoli powder

256th National Meeting (2018)

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