Encapsulation of lactic acid bacteria in W1/O/W2 emulsions stabilized by mucilage:pectin complexes.

Opuntia silvestri mucilage obtained from dried stems was explored as an emulsifier to prepare double emulsions aiming to encapsulate Lactiplantibacillus plantarum CIDCA 83114. W1/O/W2 emulsions were prepared using a two-step emulsification method. The aqueous phase (W1) consisted of L. plantarum CIDCA 83114, and the oil phase (O) of sunflower oil. The second emulsion was prepared by mixing the internal W1/O emulsion with the W2 phase, consisting of 4 % polysaccharides, formulated with different mucilage:(citric)pectin ratios. Their stability was assessed after preparation (day 0) and during storage at 4 °C (28 days). Determinations included creaming index, color, particle size, viscosity, turbidity, and bacterial viability, along with exposure to simulated gastrointestinal conditions. Significant differences were evaluated by analysis of variance (ANOVA) and Duncan's test (P < 0.05). After 28 days storage, bacterial viability in the W1/O/W2 emulsions was above 6 log CFU/mL for all the pectin:mucilage ratios. Emulsions containing mucilage and pectins showed lower creaming indices after 15 days, remaining stable until the end of the storage period. Formulations including 1:1 pectin:mucilage ratio exhibited the highest bacterial viability under simulated gastrointestinal conditions and were more homogeneous in terms of droplet size distributions at day 0, hinting at a synergistic effect between mucilage components (e.g., proteins, Ca2+) and pectin in stabilizing the emulsions. These results showed that Opuntia silvestri mucilage enhanced the stability of emulsions during refrigerated storage, highlighting its potential for encapsulating lactic acid bacteria. This presents an economical and natural alternative to traditional encapsulating materials.

Phytochemical compounds with promising biological activities from Ascophyllum nodosum extracts using microwave-assisted extraction.

Phytochemical-rich antioxidant extracts were obtained from Ascophyllum nodosum (AN) using microwave-assisted extraction (MAE). Critical extraction factors such as time, pressure, and ethanol concentration were optimized by response surface methodology with a circumscribed central composite design. Under the optimal MAE conditions (3 min, 10.4 bar, 46.8 % ethanol), the maximum recovery of phytochemical compounds (polyphenols and fucoxanthin) with improved antioxidant activity from AN was obtained. In addition, the optimized AN extract showed significant biological activities as it was able to scavenge reactive oxygen and nitrogen species, inhibit central nervous system-related enzymes, and exhibit cytotoxic activity against different cancer cell lines. In addition, the optimized AN extract showed antimicrobial, and anti-quorum sensing activities, indicating that this extract could offer direct and indirect protection against infection by pathogenic microorganisms. This work demonstrated that the sustainably obtained AN extract could be an emerging, non-toxic, and natural ingredient with potential to be included in different applications.

Seaweed bioactive compounds: Promising and safe inputs for the green synthesis of metal nanoparticles in the food industry.

Scientific research on developing and characterizing eco-friendly metal nanoparticles (NPs) is an active area experiencing currently a systematic and continuous growth. A variety of physical, chemical and more recently biological methods can be used for the synthesis of metal nanoparticles. Among them, reports supporting the potential use of algae in the NPs green synthesis, contribute with only a minor proportion, although seaweed was demonstrated to perform as a successful reducing and stabilizing agent. Thus, the first part of the present review depicts the up-to-date information on the use of algae extracts for the synthesis of metal nanoparticles, including a deep discussion of the certain advantages as well as some limitations of this synthesis route. In the second part, the available characterization techniques to unravel their inherent properties such as specific size, shape, composition, morphology and dispersibility are comprehensively described, to finally focus on the factors affecting their applications, bioactivity, potential toxic impact on living organisms and incorporation into food matrices or food packaging, as well as future prospects. The present article identifies the key knowledge gap in a systematic way highlighting the critical next steps in the green synthesis of metal NPs mediated by algae.

Nutritional and technological properties of a quinoa (Chenopodium quinoa Willd.) spray-dried powdered extract.

The relevance of an appropriate nutrition requires innovation in the design of food ingredients. The goal of this work was to obtain a powdered extract of quinoa by using spray-drying. To this aim, quinoa flour was suspended in water to obtain a soluble fraction mainly composed of proteins, starch, fiber, lipids, antioxidants and minerals. The spray-drying conditions of this quinoa soluble fraction were set-up in terms of inlet temperatures (150, 160, 170 and 180 °C) and feed flow (4.5, 7.5, 10.5 mL/min). The obtained powders were characterized by determining the proximate composition, antioxidant activity, microstructure, fatty acids' profile, and starch and proteins' structures. A correlation among the drying parameters and the chemical and functional attributes of the powders was addressed using principal component analysis. From a technological viewpoint the use of moderate feed flows (7.5 mL/min) and high inlet temperatures (180 °C) was the best combination to obtain high powder yields (85% d.b.), low aw (0.047 ± 0.005) and high solids content (0.956 ± 0.005). The drying temperature positively affected the structure of starch, improving swelling and favoring moderate agglomeration which increases the encapsulation properties of quinoa. These results support the use of spray-drying as a suitable method to obtain powdered extracts of quinoa without affecting the nutritional value, thus supporting their use as functional ingredients in the formulation of ready-to-eat foods.

Pectin Hydrolysates from Different Cultivars of Pink/Red and White Grapefruits (Citrus Paradisi [macf.]) as Culture and Encapsulating Media for Lactobacillus Plantarum.

Citrus pectin hydrolysates (Citrus paradisi [Mafc.]) from "Foster," "Red Shambar," "Tangelo Orlando," and "Citrumelo Swingle" cultivars were obtained by partial chemical hydrolysis and their properties as culture media (sole carbon/nutrient source) and encapsulating agents of Lactobacillus plantarum CIDCA 83114 were evaluated. The concentration of neutral sugars was maximal after 2-hour hydrolysis. All hydrolysates were rich in glucose >xylose >galactose >galacturonic acid >mannose >arabinose. "Citrumelo Swingle" cultivar was the one with the highest concentration of xylose. After 24 hr of fermentation with L. plantarum CIDCA 83114, bacterial viability increased from 6.76 ± 0.14 to almost 9 log CFU/mL, and lactic acid concentration, from 2.63 ± 0.41 to 7.82 ± 0.15 mmol/L in all hydrolysates. Afterwards, bacteria were entrapped in pectate-calcium beads by ionotropic gelation. Bacterial viability did not significantly decrease after freeze-drying and storage the beads at 4 °C for 45 days. PRACTICAL APPLICATION: Pectin hydrolysates were adequate culture media for microorganisms, as determined by the viabililty and lactic acid production. Considering that citrus peels are agro-wastes obtained in large quantities, their use as encapsulating materials provides a solution to overcome the environmental problem they entail.

Pectin-decorated magnetite nanoparticles as both iron delivery systems and protective matrices for probiotic bacteria.

The goal of this work was to investigate biophysical stability of iron-pectin nanoparticles and analyze the feasibility of using them as delivery systems for the probiotic strain Lactobacillus plantarum CIDCA 83114. Iron oxide (Fe3O4) nanoparticles were synthesized from 0.25M FeCl2/0.5 M FeCl3.6H2O, and coated with citrus pectins. Their physico-chemical properties [FTIR, X-ray diffraction (XRD), ζ-potential, particle size, SEM, TEM] and their effect on bacterial stabilization (viability after freeze-drying/storage, stability when exposed to simulated gastro-intestinal conditions) were assessed. XRD indicated the almost exclusive presence of magnetite crystalline phases. FTIR spectra confirmed the adsorption of pectin on magnetite nanoparticles surface. SEM and TEM images evidenced agglomerated nanoparticles, and a morphological surface change after adsorption of pectin. DLS and ζ-potential results proved the solvation of the ionizable groups in the hydrophilic network which induced chain expansion and agglomeration. Iron from nanoparticles demonstrated to be non-toxic for microorganisms up to 1.00 mg/mL. Simulated saliva and gastric solutions prevented nanoparticles from dissolution. The higher pH of the intestinal conditions (solvated -COO- and Fe-O- groups) facilitated the dispersion and partial dissolution of nanoparticles. Pectins adsorption on magnetite nanoparticles significantly enhanced electrostatic repulsion, which aided the solvation of ionized iron forms. The soluble species diffused out from the aggregates, being detected in the simulated intestinal fluid. Regarding bacterial viability, no decays were observed neither when pectin-decorated nanoparticles were exposed to simulated fluids nor when stored at 4 °C for 60 days. The composites engineered in this work appear as adequate delivery systems for probiotic bacteria, whose target is the gut.

Characterization of Pectins Extracted from Different Varieties of Pink/Red and White Grapefruits [Citrus Paradisi (Macf.)] by Thermal Treatment and Thermosonication.

The physical and chemical properties of pectin extracts obtained from different white and pink/red varieties of grapefruit [Citrus paradisi (Macf.)], using both conventional heating (CHE) and thermosonication (TS), were investigated. The content of galacturonic acid (GalA), degree of esterification (%DM), color and antioxidant capacity were analyzed. Fourier-Transform Infrared Spectroscopy (FTIR) associated with multivariate analysis enabled a structural comparison among the pectin extracts, and differential scanning calorimetry (DSC) completed a full landscape of the investigated extracts. Pectin extracts obtained by CHE showed mostly higher GalA than those obtained by TS. All the extracts had a high antioxidant capacity, as determined by 2,2 diphenyl 1-picrylhydrazyl (DPPH* ) and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS* +) assays, and a high correlation with the GalA content. The main differences observed in the FTIR spectra occurred in the 1200 to 900 cm-1 region (differences in GalA). The glass transition temperatures (Tgs) of all extracts were above 85 °C, making them interesting as stabilizing agents for the food industry. PRACTICAL APPLICATION: A wide database for the characterization of pectin extracts from grapefruits was obtained. The relationship between the extraction method and the source of pectins, with the physicochemical and antioxidant properties provided great support for their application in the food industry.