Low-energy membrane-based processes to concentrate and encapsulate polyphenols from carob pulp

Membrane Emulsification as an Emerging Method for Lacticaseibacillus rhamnosus GG® Encapsulation

Techniques capable of producing small-sized probiotic microcapsules with high encapsulation yields are of industrial and scientific interest. In this study, an innovative membrane emulsification system was investigated in the production of microcapsules containing Lacticaseibacillus rhamnosus GG® (Lr), sodium alginate (ALG), and whey protein (WPI), rice protein (RPC), or pea protein (PPC) as encapsulating agents. The microcapsules were characterized by particle size distribution, optical microscopy, encapsulation yield, morphology, water activity, hygroscopicity, thermal properties, Fourier-transform infrared spectroscopy (FTIR), and probiotic survival during in vitro simulation of gastrointestinal conditions. The innovative encapsulation technique resulted in microcapsules with diameters varying between 18 and 29 μm, and encapsulation yields > 93%. Combining alginate and whey, rice, or pea protein improved encapsulation efficiency and thermal properties. The encapsulation provided resistance to gastrointestinal fluids, resulting in high probiotic viability at the end of the intestinal phase (> 7.18 log CFU g-1). The proposed encapsulation technology represents an attractive alternative to developing probiotic microcapsules for future food applications.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11947-023-03099-w.

Polyphenol Loaded W1/O/W2 Emulsions Stabilized with Lesser Mealworm (Alphitobius diaperinus) Protein Concentrate Produced by Membrane Emulsification: Stability under Simulated Storage, Process, and Digestion Conditions

Water-in-oil-in-water (W1/O/W2) emulsions are complex delivery systems for polyphenols amongst other bio-actives. To stabilize the oil-water interphase, dairy proteins are commonly employed, which are ideally replaced by other, more sustainable sources, such as insect proteins. In this study, lesser mealworm (Alphitobius diaperinus) protein concentrate (LMPC) is assessed and compared to whey protein (WPI) and pea protein (PPI), to stabilize W1/O/W2 emulsions and encapsulate a commercial polyphenol. The results show that LMPC is able to stabilize W1/O/W2 emulsions comparably to whey protein and pea protein when using a low-energy membrane emulsification system. The final droplet size (d4,3) is 7.4 μm and encapsulation efficiency is between 72 and 74%, regardless of the protein used. Under acidic conditions, the LMPC shows a similar performance to whey protein and outperforms pea protein. Under alkaline conditions, the three proteins perform similarly, while the LMPC-stabilized emulsions are less able to withstand osmotic pressure differences. The LMPC stabilized emulsions are also more prone to droplet coalescence after a freeze-thaw cycle than the WPI-stabilized ones, but they are the most stable when exposed to the highest temperatures tested (90 °C). The results show LMPC's ability to stabilize multiple emulsions and encapsulate a polyphenol, which opens the door for application in foods.

Synthesis and characterization of microencapsulated phase change materials with chitosan-based polyurethane shell

In this paper, chitosan-based polyurethane (c-PU) microencapsulated phase change materials (MicroPCMs) were prepared via the interfacial polymerization reaction of hexamethylene diisocyanate and chitosan accompanied by the charge attraction-assisted. The utilization of natural non-toxic chitosan in MicroPCMs expanded the application of chitosan and guided a new approach to preparing green shell. And the morphology of MicroPCMs with different reaction ration, surfactant and the pH value of reaction system were systematically investigated. The MicroPCMs with c-PU shell exhibited outstanding latent thermal performance (ΔH_m = 106.3 J/g, ΔH_c = -105.1 J/g), high energy storage efficiency (E = 71.4%), excellent thermal stability and cyclic durability. The c-PU MicroPCMs with reversible photochromic show promising application in the fields of anti-counterfeiting technology and flexible wearable UV protective clothing.

Carob kibbles as an alternative raw material for production of kvass with probiotic potential

BACKGROUND

Non-diary beverages with probiotic properties are of great interest nowadays. In this research, we evaluated the suitability of carob kibbles in the manufacture of kvass. Kvass is a low-alcohol drink popular in Central and Eastern Europe and indicated as a potential non-diary beverage with probiotic properties. Therefore, the viability of probiotic strains of Lactobacillus plantarum and Saccharomyces boulardii during 4 weeks' storage in manufactured beverages was tested.

RESULTS

Carob kibbles introduced significant amounts of phenolic compounds into kvasses, especially gallic acid (up to 117.45 ± 10.56 mg L^-1 ), and improved antiradical activity up to 78% after fermentation. Moreover, fermentation efficiently reduced furfural and hydroxymethylfurfural content in samples up to 12.9% and 29.9%, respectively. Kvasses with rye malt extract possessed coffee-like, chocolate-like, roasted and caramel-like odours and a more bitter taste. Whereas kvass with carob kibbles was characterized by fruit-like odour and sweeter taste. Fermentation contributed to a creation as well as degradation of volatiles. L. plantarum exhibited higher general mortality during storage, whereas, in the case of S. boulardii, the viability was significantly higher regardless of the sample composition.

CONCLUSION

This is the first study reporting the use of carob kibbles for kvass production. The obtained results showed that carob kibbles can replace rye malt extract, at least partially, in the production of kvass, giving to the product added health benefits. Moreover, S. boulardii is a better choice for production of kvass with probiotic properties. © 2021 Society of Chemical Industry.

Combined use of β-cyclodextrin and ionic liquid as electrolyte additives in EKC for separation and determination of carob's phenolics-A study of the synergistic effect

In this work, a simple, reliable, and fast capillary electrophoretic method was developed and validated for the simultaneous determination of 12 polyphenolic compounds, the most frequently found in carob's pulp and seeds. The present work deals with the development of a novel dual electrophoretic system based on the combined use of β-CD and ionic liquid (IL) as buffer additives. A baseline separation of the target analytes was achieved in less than 10 min by using a BGE consisting of 35 mM borate along with 15 mM β-CD and 3 mM l-alanine tert butyl ester lactate (l-AlaC₄ Lac) IL as buffer additives at pH 9.5, a temperature of 25°C, and an applied voltage of 30 kV. The application of the developed electrophoretic method to real samples enabled the identification and quantification of the main phenolic constituents of both ripe and unripe carob pulp extracts. The results revealed the predominance of gallic acid in both ripe (183.92 μg/g carob pulp) and unripe (205.10 μg/g carob pulp) carob pulp and highlighted the great influence of the ripening stage on carobs polyphenolic composition, with unripe pods being more enriched in polyphenols (total phenolics detected: 912.58 and 283.13 μg/g unripe and ripe carob pulp).

Black Soldier Fly (Hermetia illucens) Protein Concentrates as a Sustainable Source to Stabilize O/W Emulsions Produced by a Low-Energy High-Throughput Emulsification Technology

There is a pressing need to extend the knowledge on the properties of insect protein fractions to boost their use in the food industry. In this study several techno-functional properties of a black soldier fly (Hermetia illucens) protein concentrate (BSFPC) obtained by solubilization and precipitation at pH 4.0–4.3 were investigated and compared with whey protein isolate (WPI), a conventional dairy protein used to stabilize food emulsions. The extraction method applied resulted in a BSFPC with a protein content of 62.44% (Kp factor 5.36) that exhibited comparable or higher values of emulsifying activity and foamability than WPI for the same concentrations, hence, showing the potential for emulsion and foam stabilization. As for the emulsifying properties, the BSFPC (1% and 2%) showed the capacity to stabilize sunflower and lemon oil-in-water emulsions (20%, 30%, and 40% oil fraction) produced by dynamic membranes of tunable pore size (DMTS). It was proved that BSFPC stabilizes sunflower oil-in-water emulsions similarly to WPI, but with a slightly wider droplet size distribution. As for time stability of the sunflower oil emulsions at 25 °C, it was seen that droplet size distribution was maintained for 1% WPI and 2% BSFPC, while for 1% BSFPC there was a slight increase. For lemon oil emulsions, BSFPC showed better emulsifying performance than WPI, which required to be prepared with a pH 7 buffer for lemon oil fractions of 40%, to balance the decrease in the pH caused by the lemon oil water soluble components. The stability of the emulsions was improved when maintained under refrigeration (4 °C) for both BSFPC and WPI. The results of this work point out the feasibility of using BSFPC to stabilize O/W emulsions using a low energy system.

Droplet breakup mechanisms in premix membrane emulsification and related microfluidic channels

Premix membrane emulsification (PME) is a pressure driven process of droplet breakup, caused by their motion through membrane pores. The process is widely used for high-throughput production of sized-controlled emulsion droplets and microparticles using low energy inputs. The resultant droplet size depends on numerous process, membrane, and formulation factors such as flow velocity in pores, number of extrusions, initial droplet size, internal membrane geometry, wettability of pore walls, and physical properties of emulsion. This paper provides a comprehensive review of different mechanisms of droplet deformation and breakup in membranes with versatile pore morphologies including sintered glass and ceramic filters, SPG and polymeric membranes with sponge-like structures, micro-engineered metallic membranes with ordered straight-through pore arrays, and dynamic membranes composed of unconsolidated particles. Fundamental aspects of droplet motion and breakup in idealized pore networks have also been covered including droplet disruption in T-junctions, channel constrictions, and obstructed channels. The breakup mechanisms due to shear interactions with pore walls and localized shear (direct breaking) or due to interfacial tension effects and Rayleigh-Plateau instability (indirect breaking) are systematically discussed based on recent experimental and numerical studies. Non-dimensional droplet size correlations based on capillary, Weber, and Ohnesorge numbers are also presented.

Techniques and modeling of polyphenol extraction from food: a review

There is a growing demand for vegetal food having health benefits such as improving the immune system. This is due in particular to the presence of polyphenols present in small amounts in many fruits, vegetables and functional foods. Extracting polyphenols is challenging because extraction techniques should not alter food quality. Here, we review technologies for extracting polyphenolic compounds from foods. Conventional techniques include percolation, decoction, heat reflux extraction, Soxhlet extraction and maceration, whereas advanced techniques are ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, high-voltage electric discharge, pulse electric field extraction and enzyme-assisted extraction. Advanced techniques are 32-36% more efficient with approximately 15 times less energy consumption and producing higher-quality extracts. Membrane separation and encapsulation appear promising to improve the sustainability of separating polyphenolic compounds. We present kinetic models and their influence on process parameters such as solvent type, solid and solvent ratio, temperature and particle size.

Encapsulation of resveratrol using Maillard conjugates and membrane emulsification

Resveratrol is a stilbene phenolic associated with health-promoting properties such as antioxidant, anti-inflammatory and chemoprevention. Due to its chemical instability and low water solubility, microencapsulation represents a good alternative to provide better results when employing resveratrol as a nutraceutical ingredient. The main purpose of our work was to use low shear membrane emulsification to produce resveratrol-loaded emulsions of low polydispersity and integrate this process to spray drying to produce a powdered product. Resveratrol was dispersed with palm oil in a continuous phase obtained via Maillard reaction. We evaluated the influence of process conditions and phases composition on emulsions properties and performed the characterization of the spray-dried powder. Emulsions droplet size and span decreased as shear stress was increased. Higher dispersed phase fluxes provided increased droplet size polydispersity. Process conditions were set on 60.0 Pa shear stress and 70 L m^-2h^-1 of dispersed phase flux, obtaining emulsions with mean diameter around 30 μm and span of 0.76. Despite this relatively high droplet size of the infeed emulsions, the spray drying process resulted in particles with high encapsulation efficiency (97.97 ± 0.01%), and water content (~3.6%) and diameter (~10.2 μm) similar to particles obtained from fine emulsions in previously reported works.

Forward Osmosis as Concentration Process: Review of Opportunities and Challenges

In the past few years, osmotic membrane systems, such as forward osmosis (FO), have gained popularity as "soft" concentration processes. FO has unique properties by combining high rejection rate and low fouling propensity and can be operated without significant pressure or temperature gradient, and therefore can be considered as a potential candidate for a broad range of concentration applications where current technologies still suffer from critical limitations. This review extensively compiles and critically assesses recent considerations of FO as a concentration process for applications, including food and beverages, organics value added compounds, water reuse and nutrients recovery, treatment of waste streams and brine management. Specific requirements for the concentration process regarding the evaluation of concentration factor, modules and design and process operation, draw selection and fouling aspects are also described. Encouraging potential is demonstrated to concentrate streams more than 20-fold with high rejection rate of most compounds and preservation of added value products. For applications dealing with highly concentrated or complex streams, FO still features lower propensity to fouling compared to other membranes technologies along with good versatility and robustness. However, further assessments on lab and pilot scales are expected to better define the achievable concentration factor, rejection and effective concentration of valuable compounds and to clearly demonstrate process limitations (such as fouling or clogging) when reaching high concentration rate. Another important consideration is the draw solution selection and its recovery that should be in line with application needs (i.e., food compatible draw for food and beverage applications, high osmotic pressure for brine management, etc.) and be economically competitive.