The hydrolysis of the water-soluble protein (WSP) fraction from tuna fish meal was evaluated by subcritical water (subW) by using N₂ and CO₂ as different pressurization agents in the temperature range from 140 to 180 °C. For both gases, the amino group release increased by increasing working temperature while the Lowry response decreased due to production of smaller-size peptides and free amino acids. The free amino acid content was higher with CO₂ than with N₂. At 180 °C, 344 ± 5 and 275 ± 3 mg of free amino acids per g of WSP were released, respectively; although, in both systems the smallest molecular weight amino acids, glycine and alanine, were preferentially released. The free amino acids content obtained by enzymatic hydrolysis with commercial proteases Alcalase and Novozym was much lower with the highest hydrolysis yield determined for histidine. These results have been supported by size exclusion chromatography analysis.

A green strategy employing water as solvent has been adopted to obtain protein hydrolysates from fish meal (FM), its water-soluble fraction (WSP), and its non-water-soluble fraction (NSP). The techno-functional properties of the hydrolysates have been investigated and compared to hydrolysates obtained with Alcalase®. In general, SWH hydrolysates presented higher content of free amino acids and higher degree of hydrolysis, which reflected on the molecular size distribution. However, Alcalase® hydrolysates presented better solubility (from 74 ± 4% for NSP at pH = 2 up to 99 ± 1% for WSP at pH = 4-7). According to fluorescence experiments, FM and NSP hydrolysates showed the highest surface hydrophobicity, which has been related to better emulsifying properties and higher emulsion stability. The emulsions stabilized with 2%wt. of SWH-treated NSP showed the smallest particle sizes, with D[4,3] = 155 nm at day 0, and good stability, with D[4,3] = 220 nm at day 7, proving that water fractionation followed by SWH treatment is a good method to improve the techno-functional properties of the hydrolysates.

Subcritical water (SCW) hydrolysis was applied to valorize the low-valued ray-finned fish (Labeobarbus nedgia) into valuable protein hydrolysates, employing N₂ and CO₂ as pressurization agents at varying temperatures (140, 160, 180, and 200 °C). The degree of hydrolysis (DH) and total free amino acid content increased with temperature for both pressurizing agents. The highest DH (54.5 ± 0.4%) and total free amino acid content (210 ± 1 mg/g_prot) were observed at 200 °C when CO₂ gas was used as the pressurizing agent. Predominantly, glycine and alanine were released for both pressurizing agents. The antioxidant activity, evaluated through three different assays, increased with temperature and was found to be the highest at 200 °C. This study illustrated the advantages of the intensified SCW technology by using CO₂ as a pressurization agent in valorizing low-valued ray-finned fish (Labeobarbus nedgia), as animal residue rich in proteins, for the production of valuable protein hydrolysates with a high fraction of valuable free amino acids, which could offer potential applications as a functional ingredient in the food industry.

The lactic acid (LA) production from corn stover using Lewis acid catalysts was optimized. Initially, an equimolar mixture of Al(III)/Sn(II) was used as a catalytic system at 190 °C with 5 wt% biomass. Increasing the catalyst concentration led to higher LA production, showing the optimal results at 16 mM. A low catalyst concentration mainly produced furfural and HMF, dehydration products from the corn stover sugars. Higher catalyst concentration increased LA yield but also produced the degradation of the glucose dehydration products into levulinic and formic acids, reducing LA selectivity. Al(III) was essential for LA formation, while Sn(II) was less effective due to its lower solubility, shown by the presence of Sn(II) in the solid residue after treatments. A total of 16 mM Al(III) yielded the highest LA levels at 190 °C, 7.4 g/L, and 20.7% yield. Increasing the temperature to 210 °C accelerated the LA production while also achieving the lowest energy consumption, which was 0.47 kWh/g LA at the highest LA production point. However, longer treatments at this temperature caused LA degradation. AlCl₃ has been identified as an ideal catalyst for biomass conversion to LA, being inexpensive and low in toxicity.

Background/Objectives: Fenbendazole is a potential cancer treatment and a proven antiparasitic in veterinary applications. However, its poor water solubility limits its application. In this study, potential fenbendazole solubility enhancement was investigated through size reduction methods. The effect of the presence of Soluplus^® on solubility was investigated as well. Methods: Solubility enhancement was explored using microfluidization and ultrasonication techniques. These techniques were applied to fenbendazole alone and in combination with Soluplus^®. UV–Vis spectroscopy was used to determine solubility. Possible chemical reactions were checked using Fourier transform infrared spectroscopy (FT-IR). Differential scanning calorimetry (DSC) was conducted to analyze the physical structure and crystallinity of the samples. Scanning electron microscopy (SEM) was also utilized for characterization of the effect of the treated formulations and the size reduction method on morphology. The elements present in samples were identified with energy-dispersive X-ray spectroscopy (EDX) combined with SEM. A comparison of crystalline structure between the products was performed via X-ray powder diffraction (XRPD). Dynamic light scattering (DLS) was also used to measure the samples’ average particle size at different stages. Results: Both ultrasonication and microfluidization led to marginal increases in the solubility of neat fenbendazole. In contrast, formulations processed in the presence of Soluplus^® demonstrated a greater enhancement in solubility. However, solubility improvement was not retained in the dried samples. The post-drying samples, irrespective of the presence of Soluplus^®, showed nearly the same solubility as neat fenbendazole. Conclusions: Size-reduction methods, particularly when combined with Soluplus^®, improved the solubility of fenbendazole. However, drying appeared to reverse these gains, regardless of the method used.