Process optimization, scale-up studies, economic analysis and risk assessment of phenolic rich bioactive extracts production from Carica papaya L. leaves via heat-assisted extraction technology

Extraction and Separation of Natural Products from Microalgae and Other Natural Sources Using Liquefied Dimethyl Ether, a Green Solvent: A Review

Microalgae are a sustainable source for the production of biofuels and bioactive compounds. This review discusses significant research on innovative extraction techniques using dimethyl ether (DME) as a green subcritical fluid. DME, which is characterized by its low boiling point and safety as an organic solvent, exhibits remarkable properties that enable high extraction rates of various active compounds, including lipids and bioactive compounds, from high-water-content microalgae without the need for drying. In this review, the superiority of liquefied DME extraction technology for microalgae over conventional methods is discussed in detail. In addition, we elucidate the extraction mechanism of this technology and address its safety for human health and the environment. This review also covers aspects related to extraction equipment, various applications of different extraction processes, and the estimation and trend analysis of the Hansen solubility parameters. In addition, we anticipate a promising trajectory for the expansion of this technology for the extraction of various resources.

Optimization studies on batch extraction of phenolic compounds from Azadirachta indica using genetic algorithm and machine learning techniques

Phenolic compounds play a crucial role as secondary metabolites due to their substantial biological activity and medicinal value. These compounds are present in various parts of plant species. This study focused on solid-liquid batch extraction to recover total phenolic compounds from Azadirachta indica leaves. The experimental design was based on the Taguchi L16 array, considering four independent factors: extraction time, temperature, particle size, and solid-to-solvent ratio. Among these factors, the particle size exerted the maximum influence. Particle size inversely affects the yield of total phenolic content (TPC), while temperature, time, and solid-to-liquid ratio have a direct impact. The process factors concerned were investigated both experimentally and through machine learning techniques. Support vector regression (SVR) and random forest method (RFM) algorithms were utilized for predicting TPC, while a genetic algorithm (GA) was employed to derive optimal process parameters. The GA predicts the optimal extraction factors, yielding the maximum TPC. During this study, these factors were the following: particle size of 0.15 mm, extraction time of 40 min, solid-to-liquid ratio of 1:25 g/mL, and a temperature of 55 °C, with a predicted value of 23.039 mg GAE/g of plant material. Notably, in this study, the SVR values of TPC yield closely matched the experimental values for the training and test data set when compared with the random forest method values.

Effect of combined application of carbonate salts and hot water treatment for the management of postharvest anthracnose (Colletotrichum gloeosporioides) of papaya

Postharvest anthracnose (Colletotrichum gloeosporioides Penz.Sacc) is the most economically important biological constraint to papaya production and consumption, which causes substantial yield loss worldwide. The effect of combined application of carbonate salts and hot water treatments on the development of postharvest anthracnose and maintenances of postharvest quality of papaya fruit was studied in completely randomized design (CRD) under laboratory condition. The results revealed that combined application of hot water treatment and carbonate salts significantly (p < .05) reduced the incidence and severity of postharvest papaya anthracnose disease. The disease incidence reached 100% 21 days after inoculation in the control treatment; this level was significantly reduced to 26.70% by dipping the fruits in NH₄CO₃ at 50°C and NH₄CO₃ at 54°C. Similarly, treatments significantly (p < .05) reduced the disease severity in different degrees from the first day of disease appearance to the date of 100% unmarketability of control fruits. Furthermore, the combined application of carbonate salt and hot water treatments significantly improves fruit marketability by 93.33%. Moreover, the treatments showed significant (p < .05) effect on maintaining pH, TSS, TA, and reducing postharvest weight loss of papaya fruit. In conclusion, postharvest treatment of papaya fruit with NH₄CO₃ at 54°C, NH₄CO₃ at 52°C, and NaCO₃ at 54°C can significantly reduce anthracnose development and improve marketability of the fruits without pronounced effect on their edible qualities.

Grape Pomace as a Natural Source of Phenolic Compounds: Solvent Screening and Extraction Optimization

The optimization of extraction by using solvents of phenolic compounds (TPh) of grape pomace (GP) based on a central composite design was investigated. The GP was characterized, and preliminary assays were conducted with five different solvents (water, ethanol, acetone, methanol, and butanol) and the aqueous mixtures thereof. Ethanol and acetone were revealed to be the best solvents for TPh extraction. The main extraction parameters (temperature—T, time—t, solvent concentration, and liquid–solid ratio—L/S) were optimized by using a central composite design. The optimized conditions for the ethanol extraction (T = 60 °C, t = 1.5 h, L/S = 25 mL/gdryGP) and for acetone (T = 50 °C, t = 1.5 h, L/S = 25 mL/gdryGP) were determined. Single-stage extraction revealed a TPh of 45.18 ± 9.51 mgGAE/gdryGP for acetone and a TPh of 38.70 ± 3.64 mgGAE/gdryGP for ethanol. The characterization of the extracts revealed the presence of gallic acid, caffeic acid, syringic acid, vanillic acid, chlorogenic acid, and p-coumaric acid, where the concentration of the first three compounds stands out in all extracts. A three-stage extraction increased the yield of ethanol to 63.3 mg GAE/gdryGP and the yield of acetone to 59.2 mg GAE/gdryGP. Overall, both solvents allow the extraction of phenolic compounds of grape pomace, but ethanol is commonly considered a greener solvent for this purpose.