Microalgae Biomass Production from Rice Husk as Alternative Media Cultivation and Extraction of Phycocyanin Using 3D-Printed Ohmic Heating Reactor.

Phycocyanin is a highly valued pigment present in Spirulina platensis biomass with applications in the food industry in terms of biorefinery concepts; specifically, its antioxidant and antimicrobial capacity are an advantage that could be incorporated into a food matrix. This study aims to use rice husk as an alternative culture medium for S. platensis biomass growth and phycocyanin extraction by ohmic heating processing using a 3D-printed reactor. S. platensis was cultivated in rice husk extract (RHE) from 0-100% (v/v). The highest content of microalgal biomass was 1.75 ± 0.01 g/L, with a specific growth rate of 0.125 ± 0.01 h-1. For the phycocyanin extraction under an ohmic heating process, a 3D-printed reactor was designed and built. To optimize phycocyanin extraction, a central composite rotatable design (CCDR) was evaluated, with three factors: time (min), temperature (°C), and pH. The highest phycocyanin content was 75.80 ± 0.98 mg/g in S. platensis biomass grown with rice husk extract. Ohmic heating is a promising method for rapid phycocyanin extraction, and rice husk as a culture medium is an alternative for the growth of S. platensis biomass in the integration of second- and third-generation biorefineries.

Determination of Nutritional and Antioxidant Properties of Maya Nut Flour (Brosimum alicastrum) for Development of Functional Foods.

Maya nut (Brosimum alicastrum) is a novel food with high nutritional value. This research aimed to evaluate the nutritional and antioxidant properties of Maya nut flour (MNF) made from seeds dried by different methods (sun-dried and using hot air at 45 °C and 60 °C) to explore its incorporation into cookies and evaluate its nutritional and functional properties. The naturally sun-dried flour (NF) had the highest content of ash (3.64 ± 0.11 g/100 g), protein (6.35 ± 0.44 g/100 g), crude fiber (6.75 ± 0.29 g/100 g), and functional properties (water and oil absorption). The color of the flour was affected by the different drying methods. While the drying methods influenced the total polyphenolic content (TPC) and antioxidant activity (AA) of MNF, they did not affect the morphology of the native starch or generated important molecular-structural changes. The substitution of 60% of wheat flour with NF in the cookie's formula increased the protein and fiber content, whereas 20% substitution increased its AA. MNF is a source of protein, dietary fiber, micronutrients, and functional compounds that can enrich cookie formulations.

Effect of Gastrointestinal Digestion on the Bioaccessibility of Phenolic Compounds and Antioxidant Activity of Fermented Aloe vera Juices.

Plant-based beverages are enriched by the fermentation process. However, their biocompounds are transformed during gastrointestinal digestion, improving their bioaccessibility, which is of primary importance when considering the associated health benefits. This study aimed to evaluate the effect of in vitro gastrointestinal digestion on phenolic compound bioaccessibility and antioxidant activity of novel Aloe vera juices fermented by probiotic Enterococcus faecium and Lactococcus lactis. Aloe vera juices were digested using the standardized static INFOGEST protocol. During digestion, phenolic compounds and antioxidant activity (DPPH, ABTS, and FRAP) were accessed. The digestion process was seen to significantly increase the total phenolic content of the fermented Aloe vera juices. The fermentation of Aloe vera increased the bioaccessibility of juice biocompounds, particularly for kaempferol, ellagic acid, resveratrol, hesperidin, ferulic acid, and aloin. The phenolics released during digestion were able to reduce the oxidative radicals assessed by ABTS and FRAP tests, increasing the antioxidant action in the intestine, where they are absorbed. The fermentation of Aloe vera by probiotics is an excellent process to increase the bioavailability of beverages, resulting in natural added-value functional products.

Fungal Proteins from Sargassum spp. Using Solid-State Fermentation as a Green Bioprocess Strategy.

The development of green technologies and bioprocesses such as solid-state fermentation (SSF) is important for the processing of macroalgae biomass and to reduce the negative effect of Sargassum spp. on marine ecosystems, as well as the production of compounds with high added value such as fungal proteins. In the present study, Sargassum spp. biomass was subjected to hydrothermal pretreatments at different operating temperatures (150, 170, and 190 °C) and pressures (3.75, 6.91, and 11.54 bar) for 50 min, obtaining a glucan-rich substrate (17.99, 23.86, and 25.38 g/100 g d.w., respectively). The results indicate that Sargassum pretreated at a pretreatment temperature of 170 °C was suitable for fungal growth. SSF was performed in packed-bed bioreactors, obtaining the highest protein content at 96 h (6.6%) and the lowest content at 72 h (4.6%). In contrast, it was observed that the production of fungal proteins is related to the concentration of sugars. Furthermore, fermentation results in a reduction in antinutritional elements, such as heavy metals (As, Cd, Pb, Hg, and Sn), and there is a decrease in ash content during fermentation kinetics. Finally, this work shows that Aspergillus oryzae can assimilate nutrients found in the pretreated Sargassum spp. to produce fungal proteins as a strategy for the food industry.

Novel Bio-Functional Aloe vera Beverages Fermented by Probiotic Enterococcus faecium and Lactobacillus lactis.

Aloe vera has been medicinally used for centuries. Its bioactive compounds have been shown to be very effective in the treatment of numerous diseases. In this work, a novel functional beverage was developed and characterized to combine the health benefits of probiotic bacteria with the Aloe vera plant itself. Two Aloe vera juices were obtained by fermentation either by a novel isolated Enterococcus faecium or a commercial Lactococcus lactis. The extraction of Aloe vera biocompounds for further fermentation was optimized. Extraction with water plus cellulase enhanced the carbohydrates and phenolic compounds in the obtained extracts. The biotransformation of the bioactive compounds from the extracts during fermentation was assessed. Both probiotic bacteria were able to grow on the Aloe vera extract. Lactic acid and short-chain fatty acids (SCFA) together with fourteen individual phenolic compounds were quantified in the produced Aloe vera juice, mainly epicatechin, aloin, ellagic acid, and hesperidin. The amount of total phenolic compounds was maintained through fermentation. The antioxidant activity was significantly increased in the produced juice by the ABTS method. The novel produced Aloe vera juice showed great potential as a functional beverage containing probiotics, prebiotics, SCFA, and phenolic compounds in its final composition.

Detoxification of ochratoxin A and zearalenone by Pleurotus ostreatus during in vitro gastrointestinal digestion.

Powdered Pleurotusostreatus (PO) was tested for the detoxification of ochratoxin A (OTA) and zearalenone (ZEN) through in vitro gastrointestinal digestion in the absence and presence of ground feed and cornmeal. Ochratoxin α was detected in the chromatograms after OTA elimination, suggesting the presence of an OTA-hydrolytic enzyme in the PO, whereas ZEN was adsorbed by PO. OTA was totally eliminated at pH 5 and 7, while ZEN was better adsorbed at pH 3. In simulated gastrointestinal conditions conducted without feed matrices, PO eliminated OTA by 85% and ZEN by 23% at the end of the intestinal phase. When digestions were conducted with ground feed and cornmeal, PO eliminated OTA by 13 and 34%, and ZEN by 20 and 2%, respectively. PO demonstrated great potential for OTA detoxification, but the feed matrices adsorbed the mycotoxins, reducing their bioaccessibility considerably in the oral and gastric phases and negatively influencing PO detoxification capacity.

Evaluation of functional and nutritional potential of a protein concentrate from Pleurotus ostreatus mushroom.

Edible mushrooms used as a protein-rich food may be an attractive alternative to conventional protein sources, while promoting its valorization. This work aimed to obtain a protein concentrate from a Pleurotus ostreatus mushroom flour, its characterization, and nutritional and functional properties evaluation. Methodologies applied for extraction and precipitation of protein were optimized - pH 4 and 12, respectively; and flour-solvent ratio of 1:20 w/v. The protein density was increased by 78%. P. ostreatus flour and concentrate were characterized by proximal composition. The content of total phenolic compounds in the protein concentrate decreased, leading to a positive effect on protein digestibility, while the DPPH radical scavenging activity was not significantly affected. Peptides with molecular weights from 12 to 35 kDa, with possible bioactivity, were identified by electrophoresis. Protein digestibility assessed by in vitro gastrointestinal digestion showed a 4.2-fold higher hydrolysis degree in the protein concentrate than the flour.

Spontaneously fermented traditional beverages as a source of bioactive compounds: an overview.

Fermented food has been present throughout history, since fermentation not only helps preserving food, but also provides specific organoleptic characteristics typically associated to these foods. Most of the traditional fermented foods and artisanal beverages are produced by spontaneous generation, meaning no control of the microbiota, or the substrate used. Nevertheless, even not being standardized, they are an important source of bioactive compounds, such as antioxidant compounds, bioactive beeps, short chain fatty acids, amino acids, vitamins, and minerals. This review compiles a list of relevant traditional fermented beverages around the world, aiming to detail the fermentation process itself-including source of microorganisms, substrates, produced metabolites and the operational conditions involved. As well as to list the bioactive compounds present in each fermented food, together with their impact in the human health. Traditional fermented beverages from Mexico will be highlighted. These compounds are of high interest for the food, pharmaceutical and cosmetics industry. To scale-up the home fermentation processes, it is necessary to fully understand the microbiology and biochemistry behind these traditional products. The use of good quality raw materials with standardized methodologies and defined microorganisms, may improve and increase the production of the desirable bioactive compounds and open a market for novel functional products.

Effect of Ohmic Heating on Sensory, Physicochemical, and Microbiological Properties of "Aguamiel" of Agave salmiana.

The use of ohmic heating (OH) processing technologies in beverages might provide a higher quality value to the final product; consumers tended to prefer more natural products with minimum preservative substances. The aim of this work was to evaluate the effect of OH over the presence of microorganisms in "aguamiel" as well as to study the effects on physicochemical analysis like total sugars, soluble solids, electric conductivity pH, and color. The results showed that the conductivity of "aguamiel" was 0.374 s/m, this as temperature increased, conductivity rose as well. During OH a bubbling was observed when reaching 70 °C due to the generation of electrochemical reactions during the OH process. OH had a significant effect in the reduction of E. coli, yeast, and lactobacillus compared to conventional pasteurization, reaching optimal conditions for its total inactivation. Regarding its physicochemical properties, both treatments, conventional pasteurization and OH, did not show negative changes in aguamiel, demonstrating that OH technology can be a feasible option as a pasteurization technique. In conclusion it is important to notice that negative changes were not found in quality, color and sugars of "aguamiel". Therefore, ohmic heating can be an option to replace traditional methods used for pasteurization.

Edible mushrooms as a novel protein source for functional foods.

Fast demographic growth has led to increasing interest in low-cost alternative protein sources to meet population needs. Consequently, scientific researchers have been focused on finding under-exploited sources of protein, alternative to those of animal origin. Usually plant proteins have been used for this purpose; however, most of them are not considered to be high quality due to their lack of some essential amino acids. Mushroom proteins usually have a complete essential amino acid profile, which may cover the dietetic requirements, as well as may have certain economic advantages as compared to animal and plant sources. Many mushrooms also have the ability to grow in agro-industrial waste, as submerged cultures, reaching high yields in a short period of time. Edible mushrooms can be processed to obtain a wide variety of food products enriched with high quality protein, which may have as well improved functional properties, giving them an added value. This review discusses the use of mushrooms as sustainable functional food.

Gallic acid production under anaerobic submerged fermentation by two bacilli strains.

BACKGROUND: Tannase is an enzyme that catalyses the breakdown of ester bonds in gallotannins such as tannic acid. In recent years, the interest on bacterial tannases has increased because of its wide applications. The lactic acid bacteria (LAB) plays an important role in food tannin biotransformation, it has the ability of hydrolyse tannins in ruminants intestine. The finding of tannin hydrolysis by LAB has sparked their use as tannase producer. RESULTS: The bacterial strains used in the present work were identified as Bacillus subtilis AM1 and Lactobacillus plantarum CIR1. The maximal tannase production levels were 1400 and 1239 U/L after 32 and 36 h of fermentation respectively, for B. subtilis AM1 and L. plantarum CIR1. Maximum gallic acid release was 24.16 g/L for B. subtilis AM1 and 23.73 g/L for L. plantarum CIR1. HPLC analysis showed the formation of another peaks in the retention time range of 9-14 min, which could be attributed to the formation of di or tri-galloyl glucose. CONCLUSIONS: According to database, the strains were identified as Bacillus subtilis AM1 and Lactobacillus plantarum CIR1. In conclusion, both strains had the capability to produce good titres of extracellular tannase and release gallic acid.

Catalytic and thermodynamic properties of a tannase produced by Aspergillus niger GH1 grown on polyurethane foam.

Tannase is an inducible enzyme with important applications in the food and pharmaceutical industries. This enzyme was produced by the fungus Aspergillus niger GH1 under solid-state fermentation using polyurethane foam as solid support and tannic acid as sole carbon source and tannase inducer. Physicochemical properties of A. niger tannase were characterized, and the kinetic and thermodynamics parameters on methyl gallate hydrolysis were evaluated. The enzyme was stable in a pH range of 2-8 and a functional temperature range of 25-65 °C. The highest k(cat) value was 2,611.10 s(-1) at 65 °C. Tannase had more affinity for methyl gallate at 45 °C with a K(M) value of 1.82 mM and an efficiency of hydrolysis (k(cat)/K(M)) of 330.01 s(-1) mM(-1). The lowest E(a) value was found to be 21.38 kJ/mol at 4.4 mM of methyl gallate. The lowest free energy of Gibbs (ΔG) and enthalpy (ΔH) were found to be 64.86 and 18.56 kJ/mol, respectively. Entropy (ΔS) was -0.22 kJ/mol K. Results suggest that the A. niger GH1 tannase is an attractive enzyme for industrial applications due its catalytic and thermodynamical properties.