Pressurized liquid extraction of phenolics from Pseuderanthemum palatiferum (Nees) Radlk. leaves: optimization, characterization, and biofunctional properties

Efficient and sustainable recovery of bioactive compounds from cashew nut testa shell (Anacardium occidentale L.) using pressurized liquid extraction

Cashew nut processing generates large quantities of byproducts daily, such as cashew nut testa shell (CNTS), which is discarded, leading to environmental and economic issues. However, CNTS contains bioactive substances such as polyphenols and antioxidant components, with potential for applications in the food, pharmaceutical, and chemical industries. This study investigated the optimization of pressurized liquid extraction (PLE) with composite central rotational design (CCRD) to evaluate the effect of the independent variables of temperature (T °C) and ethanol concentration (EtOH %) in aqueous solutions on the extraction of bioactive compounds from CNTS. The process conditions were evaluated, considering extraction yield and content of polyphenols and antioxidants from the extracts, which were identified and quantified by UPLC-PDA-ESI-QDa, and the ability of the extracts to inhibit foodborne pathogens was evaluated. Besides, a techno-economic assessment of the PLE process was also performed. The PLE conditions were optimized at 170.7 °C and 92.4% EtOH, providing better performance compared to maceration (MC) in terms of yield, phenolic content, and antioxidant potential. The recovered extracts contain catechin and epicatechin, with a higher concentration from the PLE sample compared to MC. The CNTS extracts demonstrated inhibitory effects on pathogen strains, notably inhibiting E. coli at concentrations below 0.7 mg mL-1. Scaling up the PLE process for large-scale production of CNTS extract was economically promising, considering the current market price.

Thermally optimized subcritical water hydrolysis for green extraction of bioactive compounds from sea cucumber Stichopus japonicus

This study investigated the bioactive compounds in Stichopus japonicus extracts obtained using subcritical water hydrolysis (SWH) at nine temperatures (115 °C-235 °C at 15 °C intervals). Increasing temperature enhanced the extraction efficiency and decreased the average molecular weight, extracts had abundant amino acids and phenolic compounds. Maximum protein (832.66 ± 15.00 mg BSA/g) and polysachchrides (32.02 ± 0.88 mg glucose/g) contents were achieved at 175 °C, while the highest phenolic content (23.93 ± 0.16 mg GAE/g) and antioxidant activity were observed at 220 °C. The highest α-amylase (18.62 % ± 1.17 %) and α-glucosidase (24.31 % ± 1.43 %) activities were observed at 115 °C. However, there was no significant trend between temperature and anti-inflammatory or anticholesterol activities. GC-MS analysis confirmed the presence of bioactive compounds with antioxidant, anti-inflammatory, antidiabetic, and anticholesterol potential. In conclusion, our results indicate that SWH is a sustainable approach for extracting bioactive compounds from S. japonicus, with promising applications in functional foods and therapeutics.

Biolubricants from waste cooking oil: A review of extraction technologies, conversion techniques, and performance enhancement using natural antioxidants

Effective management of agricultural and industrial by-products is essential for promoting circular economic practices and enhancing environmental sustainability. Agri-food wastes and waste cooking oil (WCO) represent two abundant residual streams with significant potential for sustainable biolubricant production. Valorizing biomass and WCO aligns with Sustainable Development Goal (SDG) 7, as it improves energy efficiency through enhanced lubricant performance and reduced energy loss. Furthermore, this sustainable approach contributes to SDG 12 and SDG 13 by minimizing waste production and accumulation, thereby mitigating negative environmental impacts and climate change. This critical review addresses existing gaps in the production of biolubricants from WCO and the incorporation of natural antioxidants as versatile additives. It examines and compares various techniques for the extraction, chemical and physical modification, and characterization of WCO-derived biolubricants. Specific methods, including esterification, transesterification, and antioxidant incorporation, are evaluated for their effectiveness in converting WCO into biolubricants. The review also discusses the influence of residual bioactive compounds on oxidative stability and lubricating properties. While vegetable oils demonstrate superior friction-reducing capabilities compared to petroleum-based lubricants, their triglyceride structure often results in poor oxidative stability, limiting their practical applications. Modification strategies and antioxidant inclusion are proposed to enhance this stability. A comprehensive analysis of the physicochemical properties and tribological performance of biolubricants, both pre- and post-processing, is presented. This systematic evaluation of extraction and upgrading methodologies aims to facilitate the development and industrial adoption of sustainable biolubricants.

A comparative study of extraction methods for recovery of bioactive components from brown algae Sargassum serratifolium

Species of Sargassum genus are known to be rich sources of bioactive compounds. However, there is a lack of studies comparing extraction methods for these bioactive components. This study aimed to compare the total phenolic contents, total antioxidant capacity, tyrosinase inhibitory effect, sargahydroquinoic acid (SHQA) and sargachromenol (SCM), two algal meroterpenoids, of Sargassum serratifolium extracts acquired by different extraction methods. The methods employed in this study included conventional solid-liquid extraction using methanol (SME), supercritical fluid extraction using CO2 with ethanol as a co-solvent (SC-CO2 + ethanol), and pressurized liquid extraction (PLE) at two temperatures (25 and 100 °C). PLE at 100 °C (PLE100) exhibited the highest total yield, total phenolic content, total antioxidant capacity and tyrosinase inhibitory activity. Notably, SME resulted in the highest recovery of both SHQA and SCM. Compared to SME, PLE100 exhibited a two-fold increase in antioxidant capacity but a minimal increase in phenolic content.

Optimization and evaluation of Atrina pectinata polysaccharides recovered by subcritical water extraction: A promising path to natural products

In this study, the recovery of Atrina pectinata posterior adductor polysaccharides (APP-PS) using subcritical water extraction (SWE) was optimized by response surface methodology (RSM) and the physicochemical and biological properties of the recovered APP-PS were evaluated. The optimal extraction conditions, which resulted in a maximum yield of 55.58 ± 1.12 %, were temperature, 152.08 °C; extraction time, 10 min; solid-liquid ratio, 30 g/600 mL. The obtained APP-PS was found to be 88.05 ± 0.17 % total sugar. Fourier transform infrared (FT-IR) and Nuclear magnetic resonance (NMR) analyses confirmed the presence of the α-coordination of D-glucan in the polymer sample. The analysis of monosaccharide composition, along with thermogravimetric analysis, revealed the typical structure of the sample, composed of glucose alone. Total phenolic contents of APP-PS were measured as 5.47 ± 0.01 mg Gallic acid/g of dry sample and total flavonoids contents were determined to be 0.78 ± 0.06 mg Quercetin/g of dry sample. For biological activities, ABTS+, DPPH and FRAP antioxidant activities were measured to be 20.00 ± 0.71, 2.35 ± 0.05 and 4.02 ± 0.07 μg Trolox equivalent/100 g of dry sample, respectively. Additionally ACE inhibitory was confirmed to be 87.02 ± 0.47 %. These results showed that SWE is an effective method to recover biofunctional materials from marine organisms.