Investigating the Effect of Supercritical Carbon Dioxide Treatment on the Rheological, Thermal, and Functional Properties of Plum (Prunus domestica L.) Kernel Protein Isolates

Supercritical carbon dioxide treatment improves the functional properties of pea protein: Application in eggless cakes

The use of plant proteins in food matrices is often limited due to inferior functional properties. Modification of proteins by supercritical carbon dioxide (scCO2) has gained attention in this regard as a safe, chemical-free, and sustainable technique. The present work explores the impact of process parameters of scCO2 modification of pea proteins on its structural and functional properties. This treatment induced the unfolding of protein structure as seen from an increase in intrinsic fluorescence and surface hydrophobicity, altered the secondary structure, and increased the free sulfhydryl groups. The scCO2 treatment positively affected the water and oil absorption capacities and enhanced the emulsifying and foaming capacity and stability. However, the rheological and film-forming properties of scCO2-modified protein were detrimentally affected at 350 bar. scCO2 modified pea proteins (250 bar/45 °C/60 min) revealed a uniform pore size distribution throughout the eggless cake matrix with sensory scores (7.34) comparable to that containing egg (7.59).

Impact of Supercritical CO2 Treatment on Lupin Flour and Lupin Protein Isolates

Global population growth is putting pressure on the food supply, necessitating the exploration of new, alternative, and sustainable protein sources. Lupin, an underutilized legume in human nutrition, has the potential to play a significant role in addressing this challenge. However, its incorporation into the human diet requires thorough investigation, including exploring and optimizing functionalization processes to maximize its potential. This study aimed to optimize the parameters (pressure, time, and CO2 flow) for extracting anti-technological factors (ATFs) from lupin using supercritical CO2 (SC-CO2) and to evaluate the effects of this extraction on both the flour and the protein isolate derived from it. Optimization revealed that the optimal SC-CO2 conditions were a CO2 flow rate of 4 kg/h at 400 bar for 93 min. Under these conditions, significant changes were observed in the flour composition, including a reduction in oil, polyphenols, and moisture content, along with an increase in ash content. Improved color parameters were also noted. These variations were attributed to the removal of oil and phenolic compounds during processing. Furthermore, this research demonstrated that SC-CO2 treatment improved lupin protein isolate (LPI) purity (93.81 ± 0.31% vs. 87.42 ± 0.48%), significantly reduced oil content (8.31 ± 0.09% vs. 14.31 ± 0.32%), and enhanced color parameters. The SC-CO2 procedure also resulted in a higher protein extraction yield (56.95 ± 0.45% vs. 53.29 ± 2.37%). However, the total extraction yield (g LPI/100 g of flour) was not affected by SC-CO2 treatment, remaining at 24.30 ± 0.97% for the control sample and 24.21 ± 0.26% for the treated sample. The extracted oil (2.71 ± 0.11 g/100 g of flour), a co-product of the SC-CO2 step, exhibited a fatty acid profile characterized by high levels of unsaturated fatty acids (62.8 ± 0.74 g/100 g oil), oleic acid (27.76 ± 0.77 g/100 g oil), linoleic acid (25.98 ± 0.73 g/100 g oil), and α-linolenic acid (5.32 ± 0.16 g/100 g oil), as well as a balanced ratio of essential fatty acids (n-6/n-3 = 4.89). The treatment had minimal to no effect on amino acid content or chemical score, and the protein was characterized by high amounts of essential amino acids (334 ± 3.12 and 328 ± 1.05 mg/g protein in LPI-control and LPI-SF, respectively). These findings demonstrate that both the LPI and the oil extracted using SC-CO2 possess high nutritional quality and are suitable for human food applications.

Use of supercritical CO2 to improve the quality of lupin protein isolate

Lupins are an excellent source of protein which can be used to obtain protein isolates with potential use in the food industry. Some studies use supercritical CO2 (SC-CO2) to defat legume flours, but no study analyzes the effect of applying this technology directly to the protein isolate. This article has proposed the use of SC-CO2 to improve lupin protein isolate (LPI) quality. SC-CO2 increased the LPI purity while reducing oil and other antitechnological factors (saponins and polyphenols). The treatment significantly improved the LPI color due to the elimination of the lipid fraction and lipophilic pigments (carotenoids). No changes in amino acid contents or chemical score were observed due to the SC-CO2. Finally, the treatment improved or did not affect the main LPI technofunctional properties. Therefore, SC-CO2 is a promising technique to enhance the quality of protein isolates, without affecting or improving their functional properties.

Viscoelastic behavior, gelation properties and structural characterization of Deccan hemp seed (Hibiscus cannabinus) protein: Influence of protein and ionic concentrations, pH, and temperature

This study investigates the viscoelastic behavior, gelling properties, and structural characteristics of Deccan hemp seed protein (DHSP) to overcome limitations in its application in food formulations. Small amplitude oscillatory shear measurements were employed to investigate the impact of protein concentration, pH, ionic concentration, and temperature on DHSP's rheological features. The study revealed that the 20 % protein dispersion had the highest storage modulus (G') and yield stress at 63.96 ± 0.23 Pa and 0.61 Pa, respectively. DHSP dispersion exhibited pseudo-plastic behavior across various conditions. The gelling performance was higher at pH 4 and 8 and at ionic concentration in the range of 0.1 M - 0.5 M. Gelation time and temperature were observed from the temperature ramp test. Structural characterizations, including fluorescence spectroscopy, circular dichroism spectra, FTIR spectra, SEM, AFM images, zeta potential analysis, and DSC, provided insights into DHSP's tertiary and secondary conformation, surface characteristics, and thermal properties. Notably, the study highlighted DHSP's exceptional rheological properties, making it a promising gelling material for the food and nutraceutical industries. The findings also offer new insights into DHSP's structural characteristics, suggesting potential applications in food packaging and product development within the food industry.

Valorization of Soybean Residue (Okara) by Supercritical Carbon Dioxide Extraction: Compositional, Physicochemical, and Functional Properties of Oil and Defatted Powder

In the context of food waste valorization, the purpose of this study is to demonstrate the complete valorization of soybean residue (okara) through supercritical carbon dioxide extraction (SCE). Okara oil (OKO) was separated from full-fat powder (FFP) using SCE with and without ethanol (EtOH) as a cosolvent. The kinetics of extraction, chemical composition, and physicochemical, functional, and health-promoting properties of OKO and defatted powder (DFP) were determined. The process yielded 18.5% oil after 450 min. The soluble dietary fiber and protein of the DFP increased significantly; its water and oil absorption capacities increased despite the decrease in swelling capacity corresponding to particle size reduction. The OKO was rich in linoleic and oleic acids, with a ratio of ω6-to-ω3 fatty acids = 9.53, and EtOH increased its phenolic content (0.45 mg GAE/g), aglycone content (239.6 μg/g), and antioxidant capacity (0.195 mg TE/g). The DFP paste showed gel-like consistency and shear-thinning flow behavior, whereas the OKO showed characteristic transition of the product and affected lubrication at contact zones. Both fractions showed potential as food ingredients based on their nutritional and functional properties, as well as the capability of modifying the microstructure of a model food system.