Preservative effect of cactus pear fruit (Opuntia spp.) extract on the microbial quality of FPC-fortified functional oat cookies during storage

Abstract

The present study focused on the development of functional oat-based cookies fortified with fish protein concentrate (FPC) derived from lesser tiger-toothed croaker (Otolithes cuvieri) and cactus pear fruit (Opuntia spp.) extract, and on evaluating their microbiological stability during storage. FPC was incorporated at 2% (w/w) to enhance protein content, while cactus pear extract, a rich source of antioxidants, dietary fiber, minerals, and natural flavor compounds, was added at varying levels (1-10%). Cookies were prepared, baked, and stored at room temperature, and microbial analysis—including total plate count (TPC), mold, and yeast—was conducted at 15-day intervals over a 90-day period. Results indicated that TPC, mold, and yeast counts gradually increased during storage but remained within permissible limits for all treatments, with fortified cookies exhibiting significantly lower microbial growth compared to the control. The highest level of cactus pear extract (10%) was most effective in inhibiting microbial proliferation. Fortification with FPC and cactus pear extract not only improved the nutritional profile of the cookies by enhancing protein, fiber, and micronutrient content but also contributed to improved storage stability. The findings suggest that these fortified cookies can serve as a health-promoting, shelf-stable snack suitable for health-conscious consumers.