Integrated Processes Turning Pepper Sauce Waste into Valuable By-Products

Background: Safe and efficient disposal of millions of tons of pepper sauce waste (PSW) can be a challenge to pepper sauce manufacturers that are concerned about creating environmental hazards from the processing (e.g., preservative salt and vinegar) and intrinsic (e.g., the pungent capsaicins) ingredients. It will be immensely beneficial to process these waste materials before they go to disposal. This work presents integrated approaches for a complete utilization of waste materials by removing and recovering valuable by-products and/or ingredients while succeeding to minimal to zero hazards. Methods: Laboratory- and pilot-scale extraction processes were used to demonstrate the recovery of intrinsic compounds from PSW to pungent pepper oil. Flash chromatography was then applied to isolate the pungent capsaicins out of the pepper oil, thus generating a no-heat pepper oil. Results: By processing the waste materials, a number of valuable by-products with various yield percentages were produced. They included (1) hot red pepper oil (RPO, 8.0% v/w), (2) no-heat pepper residue (NHPR, 25.3% w/w), (3) no-heat red pepper oil (NHRPO, 4.0% v/w), (4) capsaicinoids (0.8% w/w), and (5) capsaicin (0.4% w/w). The optimum processing conditions for products 1, 2, and 3 include extracting the waste materials with 95% ethanol twice, each lasting three hours. The optimal isolation conditions of flash column chromatography to obtain products 4 and 5 include the use of the pre-packed chromatography column 130 g Redisep C18, preparing the sample concentration to 100 mg/mL, eluting with aqueous ethanol, and detecting capsaicins at a wavelength of 228 nm. Conclusions: An integrated approach is offered for the complete utilization of PSW. It not only turns organic food waste into numerous new commodities but also significantly reduces the volume and degree of potential environmental hazard to the disposal sites.