Effects of ultrafiltration membrane processing on the metabolic and sensory profiles of coffee extracts

In the coffee industry, the use of natural coffee extracts with differentiated attributes is desirable to drive new product development. This study evaluates the impact of ultrafiltration membrane processing on the sensory, metabolic, and physicochemical attributes of four commercially available coffee extracts: cold brew, lightly roasted, freeze concentrated and evaporated standard. The sensory analysis revealed an increase in acidity in the permeate across all extracts, with the most significant profile changes observed in the lightly roasted evaporated and evaporated extracts, accompanied by an enhancement of fruity and floral attributes. Furthermore, the permeate showed reduced total dissolved solids, while the caffeine concentration increased. Metabolomic analysis highlighted key coffee-related metabolites like cinnamic and coumaric acids, explaining observed variations due to their passage through the membrane. Our findings emphasize the potential of permeate as a coffee-based ingredient for ready-to-drink products development, providing a unique coffee experience with organoleptic profiles distinct from traditional beverages.

Optimization of fractionation with membranes of antioxidant enzymatic hydrolysate of Californian red worm (Eisenia fetida) protein

Problem

Earthworm is a valuable source of biologically and pharmacologically active compounds, with applications in the treatment of various types of diseases; however, the main application they have been given is in the production of organic fertilizer. One of the alternatives for obtaining bioactive compounds is by means of enzymatic hydrolysis.

Aim

This study proposes the optimization of the fractionation of the antioxidant enzymatic hydrolysate from Californian red worm (Eisenia fetida) protein.

Methodology

For this purpose, the worms were separated and hydrolyzed using the enzyme Alcalase 2.4L for 4000s. The obtained hydrolysate was fractionated by means of a crossflow tangential ultrafiltration system, with a 3 kDa molecular weight cut-off ceramic membrane. A response surface design of the composite central factorial type was implemented to evaluate the effect of pH, transmembrane pressure, and flow factors on the response variables transmission, volume reduction factor (VRF) and permeate flow resistance. The transmissions focused on the antioxidant peptides, measured by three conventional methods such as TEAC, FRAP, ORAC, also known as TTEAC, TFRAP and TORAC, respectively. The evaluated resistances were the total resistance (Rtotal), fouling resistance (Rfouling), and gel resistance (Rgel).

Result

The results showed that the three factors evaluated affect all the response variables either in their linear or quadratic terms or by some interaction. For each response variable, a mathematical model was obtained, with statistical significance and a non-significant lack of adjustment. The models obtained were used for a multi-objective optimization process in which transfers were maximized, and resistances were minimized. The efficiency of the optimum ultrafiltration process was 25 %.

Conclusion

The neutral-alkaline pH is ideal for the ultrafiltration process of bioactive peptides, as it is where the highest transmissions of peptides with antioxidative capacity are found. Under optimal conditions, the 3 kDa membrane permeate was found to exhibit higher antioxidant capacity than the retentate and feed. Based on this, the fraction of less than 3 kDa emerges as a potential multifunctional ingredient, thanks to its antioxidant properties.

Evaluation of Concentration Polarization Due to the Effect of Feed Water Temperature Change on Reverse Osmosis Membranes

Water is a necessary resource for life development. Its excessive consumption has a negative impact, generating scarcity problems worldwide. Desalination is an alternative to solve these problems; its objective is to reduce the concentration of total dissolved solids to levels suitable for consumption. The most widely used desalination technology is reverse osmosis, which works by means of semipermeable membranes; however, lack of knowledge or wrong operation cause phenomena such as concentration polarization, which reduces the effective area for mass transfer in the membrane, increasing the energy consumption of the process. The objective of the present study is to evaluate the concentration polarization (β) of the concentration in reverse osmosis membranes by varying the temperature in the feed water (23, 25.5, 28, and 35 °C) for different concentrations (5000 and 10,000 mg L^-1) in order to reduce its impact on energy consumption (kWh m^-3). The results show that as the temperature increases, the specific energy consumption decreases for both concentrations. In the 5000 mg L^-1 tests, the specific energy consumption decreased by 0.590 kWh m^-3, representing 12.5%. For 10,000 mg L^-1 tests, the specific energy consumption shows a reduction of 0.72 kWh m^-3, which represents a percentage decrease of 14.54%.

A new design for obtaining of white zein micro- and nanoparticles powder: antisolvent-dialysis method

The objective of this work was propose antisolvent-dialysis as a new, easy, one-step and reproducible method for obtaining white zein micro- and nanoparticles powder. Firstly, the study by SEM of white zein powder predicted micro- and nanoparticles with spherical morphology and average diameters of 243.2 ± 94.5 nm for nanoparticles and 0.74 ± 0.2 μm for microparticles. UV-Vis predicted lower absorbance of 250-500 nm for white zein powder compared to commercial yellow zein powder. FT-IR showed shifting of the main bands to the right, due to changes in particle-shaped microstructure that acquires white zein powder compared to yellow zein powder. In TGA white zein powder showed a decomposition range from 214 to 400 °C, while yellow zein powder from 240 to 400 °C. Therefore, antisolvent-dialysis is new method to obtain white zein micro- and nanoparticles with potential applications such as polymer matrix and white natural coloring.

Current Advances in Biofouling Mitigation in Membranes for Water Treatment: An Overview

Membranes, as the primary tool in membrane separation techniques, tend to suffer external deposition of pollutants and microorganisms depending on the nature of the treating solutions. Such issues are well recognized as biofouling and is identified as the major drawback of pressure-driven membrane processes due to the influence of the separation performance of such membrane-based technologies. Herein, the aim of this review paper is to elucidate and discuss new insights on the ongoing development works at facing the biofouling phenomenon in membranes. This paper also provides an overview of the main strategies proposed by “membranologists” to improve the fouling resistance in membranes. Special attention has been paid to the fundamentals on membrane fouling as well as the relevant results in the framework of mitigating the issue. By analyzing the literature data and state-of-the-art, the concluding remarks and future trends in the field are given as well.