Around 20–30% of the horned melon’s weight is peel. This peel is often discarded or underutilized despite containing valuable bioactive compounds. Conventional methods for extracting polyphenols and carotenoids from horned melon peel are typically inefficient, environmentally harmful, or require significant time and energy. The potential of green cloud point extraction (CPE) or green surfactant-based extraction for recovering bioactives with different polarities from this kind of by-product has not been thoroughly investigated. Therefore, this study focused on optimizing CPE process parameters using a one-variable-at-a-time (OVAT) approach. Optimal CPE demonstrated superior yields compared to conventional, ultrasound, microwave, ultrasound-assisted CPE, and microwave-assisted CPE methods. Further, a Plackett–Burman design identified key factors influencing optimal CPE conditions, while artificial neural network (ANN) analysis assessed each input variable’s impact on outcomes. Maximum extraction efficiency for total phenolics (352.49 mg GAE/100 g), total carotenoids (16.59 mg β-carotene/100 g), and antioxidant activity (989.02 μmol TE/100 g) was achieved under conditions of: surfactant type = Tween 80, surfactant concentration = 2%; solid:liquid ratio = 1:100; pH = 6612; equilibration temperature = 35 °C; equilibration time = 60 min; salt type = NaCl; salt concentration = 16.4%; centrifugation speed = 7906× g ; centrifugation time = 13.358 min; and No. of CPE steps = Step 1. This comprehensive approach aimed to enhance the understanding and optimization of CPE for maximizing the recovery of bioactives from the horned melon peel, addressing the inefficiencies of traditional extraction methods.

Fermentation is increasingly used as a controlled bioprocessing approach to modify medicinal plant extracts by selectively transforming phytochemicals while maintaining safety and compositional integrity. Controlled in vitro fermentation has gained attention as a practical method to generate stable, cell-independent bioactivity consistent with postbiotic concepts. This review examines Scopus-indexed studies on fermented medicinal plant extracts, focusing on microbial platforms, fermentation strategies, dominant biotransformation pathways, and functional outcomes. Evidence indicates that fermentation is not a uniform process but follows platform-specific enzymatic pathways that reshape phenolics, flavonoids, alkaloids, and polysaccharides. Lactic acid bacteria (LAB) are most frequently applied due to their safety profile and enzymatic capacity, while yeasts and filamentous fungi enable complementary matrix restructuring and deeper chemical modification. Across systems, fermentation-driven biotransformation produces bioactive profiles that persist independently of microbial viability, supporting a postbiotic-oriented interpretation. Applications have been reported in food, nutraceutical, cosmetic, and animal nutrition contexts, although clinical translation remains limited. Remaining challenges include incomplete mechanistic understanding, limited standardization, and unclear regulatory positioning.

Spent coffee grounds (SCG), a solid by-product generated during coffee preparation, are produced in substantial quantities yet remain largely underexploited. The valorization of SCG offers significant environmental, economic, and social advantages, contributing to the advancement of a circular bioeconomy. In this study, SCG valorization consisted of two steps. In the first step, the SCG was depleted by supercritical CO₂ at 250 bar for 4 h, and by using two different temperatures: 40 °C and 60 °C. In the second step, the defatted SCG was subjected to subcritical water extraction at different temperatures, and ultrasound-assisted extraction at both different amplitudes and temperatures. The objective of this study was to evaluate a sequential extraction approach for the recovery of fatty acid methyl esters (FAMEs) and the subsequent maximization of caffeine extraction from SCG. The FAME profile was determined in ten supercritical fluid extracts and two Soxhlet extracts, while caffeine content was evaluated in five subcritical water extracts and six ultrasound-assisted extracts obtained from SCG, previously exhausted by supercritical CO₂ extraction. The highest caffeine content was present in a subcritical extract obtained at 180 °C, while the most abundant fatty acids found in all the tested extracts were linoleic acid (43.79–54.15%) and palmitic acid (32.73–45.85%). The predominance of linoleic and palmitic acids in the obtained extracts suggests their potential application as feedstocks for biodiesel production and oleochemical industries. Furthermore, the high content of linoleic acid, an essential polyunsaturated fatty acid, may enhance the value of these extracts for cosmetic and nutraceutical applications.