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.

Recent advances in ß-galactosidase and fructosyltransferase immobilization technology.

The highly demanding conditions of industrial processes may lower the stability and affect the activity of enzymes used as biocatalysts. Enzyme immobilization emerged as an approach to promote stabilization and easy removal of enzymes for their reusability. The aim of this review is to go through the principal immobilization strategies addressed to achieve optimal industrial processes with special care on those reported for two types of enzymes: ß-galactosidases and fructosyltransferases. The main methods used to immobilize these two enzymes are adsorption, entrapment, covalent coupling and cross-linking or aggregation (no support is used), all of them having pros and cons. Regarding the support, it should be cost-effective, assure the reusability and an easy recovery of the enzyme, increasing its stability and durability. The discussion provided showed that the type of enzyme, its origin, its purity, together with the type of immobilization method and the support will affect the performance during the enzymatic synthesis. Enzymes' immobilization involves interdisciplinary knowledge including enzymology, nanotechnology, molecular dynamics, cellular physiology and process design. The increasing availability of facilities has opened a variety of possibilities to define strategies to optimize the activity and re-usability of ß-galactosidases and fructosyltransferases, but there is still great place for innovative developments.

Release of health-related compounds during in vitro gastro-intestinal digestion of okara and okara fermented with Lactobacillus plantarum.

Okara is a highly perishable by-product remaining after filtration of the smashed soybeans seeds in the production of soymilk. Due to its nutritional value, different approaches have been developed to use it as functional ingredient. Fermentation of okara appears as an interesting strategy to preclude spoilage, providing a more stable matrix to be incorporated in the formulation of functional foods. Okara has antioxidant compounds but the effect of fermentation, and their bioaccessibility still need to be investigated. To achieve this aim, the phenolic compounds (as determined by TPC and TFC assays) and the antioxidant properties (as determined by ABTS ·+, DPPH · , O2 ·- assays) of okara and okara fermented with Lactobacillus plantarum CIDCA 83114 were assessed both before and after exposure to simulated gastro-intestinal conditions. Before digestion, okara showed higher values of TPC and TFC than the fermented counterpart. Although a decrease of TPC and TFC was observed after exposing okara to gastric conditions, no significant differences between okara and fermented okara were detected. No further decrease of TPC were observed in intestinal conditions. Okara showed higher antioxidant activity than fermented okara. There was a considerable decrease in the antioxidant activity for both samples when exposed to gastric and intestinal conditions. A good correlation between TFC and antioxidant activities was detected, suggesting that flavonoids play an important role as antioxidants. As a whole, this work provides a solid support for the stability of phytochemicals along the digestive process of both okara and fermented okara.

Factors influencing the membrane fluidity and the impact on production of lactic acid bacteria starters.

Production of lactic acid bacteria starters for manufacturing food, probiotic, and chemical products requires the application of successive steps: fermentation, concentration, stabilization, and storage. Despite process optimization, losses of bacterial viability and functional activities are observed after stabilization and storage steps due to cell exposure to environmental stresses (thermal, osmotic, mechanical, and oxidative). Bacterial membrane is the primary target for injury and its damage is highly dependent on its physical properties and lipid organization. Membrane fluidity is a key property for maintaining cell functionality, and depends on lipid composition and cell environment. Extensive evidence has been reported on changes in membrane fatty acyl chains when modifying fermentation conditions. However, a deep characterization of membrane physical properties and their evolution following production processes is scarcely reported. Therefore, the aims of this mini-review are (i) to define the membrane fluidity and the methods used to assess it and (ii) to summarize the effect of environmental conditions on membrane fluidity and the resulting impact on the resistance of lactic acid bacteria to the stabilization processes. This will make it possible to highlight existing gaps of knowledge and opens up novel approaches for future investigations.

Influence of different storage conditions on the performance of spray-dried yogurt used as inoculum for milk fermentation.

A commercial drinkable yogurt with and without 4% of added trehalose (as cell protectant) was spray-dried obtaining a powder with low water activity (aw). Total bacterial count in the powder was between 8.48-8.90 log cfu/g. The dried yogurt was stored: (i) at 38 °C and aw = 0.33; (ii) at 38 °C in hermetically sealed flasks (aw = 0.21/0.22); (iii) in a cyclic temperature chamber (10-20 °C) in hermetically sealed flasks (aw = 0.21/0.22). Whole milk was then fermented by adding an inoculum of spray-dried yogurt after storage under these different conditions. The kinetics of acidification showed the presence of a lag time which was strongly dependent on storage conditions. The data was fitted with a logistic type equation from which the lag time was calculated. To evaluate structural differences among samples, Fourier Transform Infrared spectra (FTIR) were recorded. Partial Least Squares (PLS) models enabled a good correlation between lag time of fermentation and FTIR spectra. The lag time for yogurt powder stored at aw about 0.21/0.22 and cyclic temperature 10-20 °C remained approximately constant over the 12 weeks of storage, while all the other conditions resulted in a dramatic increase. The addition of trehalose had a small influence on lag time and, therefore, as a protectant of lactobacilli.

Relationship between carbohydrate composition and fungal deterioration of functional strawberry juices preserved using non-thermal treatments.

BACKGROUND: The quantification of the main carbohydrates present in strawberry juices enriched with inulin and fructo-oligosaccharides (FOS) and preserved by non-thermal techniques (vanillin and ultrasound) was conducted, in addition to an investigation of the evolution of these compounds and their relationship with fungal deterioration over 14 days of refrigerated storage. RESULTS: A simple and environmentally friendly analytical approach based on high-performance liquid chromatography with a reflection index detector was developed for simultaneous determination of inulin, FOS and mono- and disaccharides present in the juices. When analyzing the evolution of carbohydrates during storage, a direct relationship between the consumption of sucrose and the growth of yeasts and molds (main spoilage flora in strawberry) was observed, especially in untreated samples (control). By contrast, no sucrose consumption was observed during storage of the treated sample, thus demonstrating the efficiency of the non-thermal treatments for controlling yeasts and mold growth. In turn, inulin and FOS added to juices were not degraded during storage. CONCLUSION: The results obtained in the present study demonstrate that non-thermal treatments are adequate for preventing the growth of deteriorative flora in strawberry juices and that the addition of inulin and FOS can be a good strategy for functionalizing them, as well as improving their nutritional properties. © 2017 Society of Chemical Industry.

Incorporation of Lactobacillus plantarum and zeolites in poultry feed can reduce aflatoxin B1 levels.

The aim of this work was to evaluate the incorporation of a freeze-dried probiotic strain (Lactobacillus plantarum CIDCA 83114) into zeolites. The bacteria-zeolite mixture was added to poultry feed together with thyme, and the obtained product was stored for 60 days at 25 °C and 60-70% relative humidity. The ability of the obtained product to remove aflatoxin B1 (AFB1) was studied. The highest bacterial viability was observed when 50% w/w bacteria were added to zeolites. The bacterial:zeolite mixtures were then incorporated into poultry feed containing or not thyme. Initial counts of L. plantarum were in the range of 1-2 × 108 CFU/g for all samples. In all cases, bacterial viability decreased one logarithmic order after 20 days of storage, and three logarithmic orders after 60 days. No significant viability loss was observed after exposure of the poultry feed to gastro-intestinal conditions. Freeze-dried L. plantarum and zeolite were able to remove AFB1, with an average reduction of 20 and 80%, respectively. Moreover, the freeze-dried bacteria-zeolite mixture was capable to remove up to 90% AFB1. This work contributes to enhance the nutritional quality of poultry feed, with a strong impact in production.

Malt sprout, an underused beer by-product with promising potential for the growth and dehydration of lactobacilli strains.

Malt sprout (MS), a by-product of the malt industry obtained by removing rootlets and sprouts from the seed of germinated barley (Hordeum vulgare L.), was used as culture, dehydration and storage medium of three strains of lactobacilli: Lactobacillus salivarius CM-CIDCA 1231B and CM-CIDCA 1232Y and Lactobacillus plantarum CIDCA 83114. The three strains were grown in MS and MS supplemented with 20% w/v fructo-oligosaccharides (MS FOS). Bacterial growth was determined by registering the decrease of pH and by plate counting. Comparable results with those of microorganisms grown in MRS (controls) were observed in terms of lag times, ΔpH and acidification rates. Furthermore, during fermentation, a significant increase of DP6 (FOS with degree of polymerization 6) was observed at expenses of inulin and DP7, probably indicating their hydrolysis. A concomitant decrease of DP3, sucrose and monosaccharides was also observed, as result of their bacterial consumption during growth. The presence of FOS in the fermented media protected microorganisms during freeze-drying and storage, as no decrease of culturability was observed after 60 days at 4 °C (> 108 CFU/mL). Using MS appears as an innovative strategy for the production of lactobacilli at large scale, supporting their use for the elaboration of functional foods containing prebiotics and probiotics.

Effect of protective agents and previous acclimation on ethanol resistance of frozen and freeze-dried Lactobacillus plantarum strains.

The aim of this work was to study the protective effect of sucrose, trehalose and glutamate during freezing and freeze-drying of three oenological Lactobacillus plantarum strains previously acclimated in the presence of ethanol. The efficiency of protective agents was assessed by analyses of membrane integrity and bacterial cultivability in a synthetic wine after the preservation processes. No significant differences in the cultivability, with respect to the controls cells, were observed after freezing at -80 °C and -20 °C, and pre-acclimated cells were more resistant to freeze-drying than non-acclimated ones. The results of multiparametric flow cytometry showed a significant level of membrane damage after freeze-drying in two of the three strains. The cultivability was determined after incubation in wine-like medium containing 13 or 14% v/v ethanol at 21 °C for 24 h and the results were interpreted using principal component analysis (PCA). Acclimation was the most important factor for preservation, increasing the bacterial resistance to ethanol after freezing and freeze-drying. Freeze-drying was the most drastic method of preservation, followed by freezing at -20 °C. The increase of ethanol concentration from 6 to 10% v/v in the acclimation medium improved the recovery of two of the three strains. In turn, the increase of ethanol content in the synthetic wine led to a dramatic decrease of viable cells in the three strains investigated. The results of this study indicate that a successful inoculation of dehydrated L. plantarum in wine depends not only on the use of protective agents, but also on the cell acclimation process prior to preservation, and on the ethanol content of wine.

Novel Functional Whey-Based Drinks with Great Potential in the Dairy Industry.

This work focuses on the production of liquid whey protein concentrates by ultrafiltration followed by thermal denaturation and homogenization of the ultrafiltrated concentrate, as well as on the production of ultrafiltrated permeates concentrated by reverse osmosis. Kefir grains (fresh and thawed) and/or commercial probiotic bacteria were inoculated in both liquid whey protein concentrates and concentrated ultrafiltrated permeates and grown at 25 °C for 24 h for the manufacture of fermented drinks. The physicochemical characterization (pH, titratable acidity, viscosity, and content of total solids, ash, fat and proteins) of the obtained drinks was then assessed and compared. Enumeration of viable microorganisms was carried out immediately after inoculation (at 0 h), during the fermentation period (at 12 and 24 h) and during refrigerated storage (at 48, 168 and 336 h). The fermented drinks showed acceptable physicochemical and sensorial properties, and contained above 7 log CFU/mL of lactococci and lactobacilli and 6 log CFU/mL of yeasts after 14 days of refrigerated storage, which is in agreement with the standards required by international organizations like European Food Safety Authority (EFSA) and Food and Drug Administration (FDA) for products containing probiotics. In summary, the strategy developed in this work contributes to the expansion of the applications of products derived from whey fractionation for the design of novel functional foods.

Role of S-layer proteins in the biosorption capacity of lead by Lactobacillus kefir.

The role of S-layer proteins (SLP) on the Pb(2+) sequestrant capacity by Lactobacillus kefir CIDCA 8348 and JCM 5818 was investigated. Cultures in the stationary phase were treated with proteinase K. A dot blot assay was carried out to assess the removal of SLP. Strains with and without SLP were exposed to 0-0.5 mM Pb(NO3)2. The maximum binding capacity (q max ) and the affinity coefficient (b) were calculated using the Langmuir equation. The structural effect of Pb(2+) on microorganisms with and without SLP was determined using Raman spectroscopy. The bacterial interaction with Pb(2+) led to a broadening in the phosphate bands (1,300-1,200 cm(-1) region) and strong alterations on amide and carboxylate-related bands (νCOO(-) as and νCOO(-) s). Microorganisms without SLP removed higher percentages of Pb(2+) and had higher q max than those bearing SLP. Isolated SLP had much lower q max and also removed lower percentages of Pb(2+) than the corresponding whole microorganisms. The hydrofobicity of both strains dramatically dropped when removing SLP. When bearing SLP, strains do not expose a large amount of charged groups on their surfaces, thus making less efficient the Pb(2+) removal. On the contrary, the extremely low hydrofobicity of microorganisms without SLP (and consequently, their higher capacity to remove Pb(2+)) can be explained on the basis of a greater exposure of charged chemical groups for the interaction with Pb(2+). The viability of bacteria without SLP was not significantly lower than that of bacteria bearing SLP. However, microorganisms without SLP were more prone to the detrimental effect of Pb(2+), thus suggesting that SLP acts as a protective rather than as a sequestrant layer.

Conformers, infrared spectrum, UV-induced photochemistry, and near-IR-induced generation of two rare conformers of matrix-isolated phenylglycine.

The conformational space of α-phenylglycine (PG) have been investigated theoretically at both the DFT/B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of approximation. Seventeen different minima were found on the investigated potential energy surfaces, which are characterized by different dominant intramolecular interactions: type I conformers are stabilized by hydrogen bonds of the type N-H···O=C, type II by a strong O-H···N hydrogen bond, type III by weak N-H···O-H hydrogen bonds, and type IV by a C=O···H-C contact. The calculations indicate also that entropic effects are relevant in determining the equilibrium populations of the conformers of PG in the gas phase, in particular in the case of conformers of type II, where the strong intramolecular O-H···N hydrogen bond considerably diminishes entropy by reducing the conformational mobility of the molecule. In consonance with the relative energies of the conformers and barriers for conformational interconversion, only 3 conformers of PG were observed for the compound isolated in cryogenic Ar, Xe, and N2 matrices: the conformational ground state (ICa), and forms ICc and IITa. All other significantly populated conformers existing in the gas phase prior to deposition convert either to conformer ICa or to conformer ICc during matrix deposition. The experimental observation of ICc had never been achieved hitherto. Narrowband near-IR irradiation of the first overtone of νOH vibrational mode of ICa and ICc in nitrogen matrices (at 6910 and 6930 cm(-1), respectively) led to selective generation of two additional conformers of high-energy, ITc and ITa, respectively, which were also observed experimentally for the first time. In addition, these experiments also provided the key information for the detailed vibrational characterization of the 3 conformers initially present in the matrices. On the other hand, UV irradiation (λ = 255 nm) of PG isolated in a xenon matrix revealed that PG undergoes facile photofragmentation through two photochemical pathways that are favored for different initial conformations of the reactant: (a) decarboxylation, leading to CO2 plus benzylamine (the dominant photofragmentation channel in PG cis-COOH conformers ICa and ICc) and (b) decarbonylation, with generation of CO plus benzonitrile, H2O and H2 (prevalent in the case of the trans-COOH conformer, IITa).

Removal of cadmium by Lactobacillus kefir as a protective tool against toxicity.

The aim of this work was to evaluate the capacity of Lactobacillus kefir strains to remove cadmium cations and protect eukaryotic cells from cadmium toxicity. Lb. kefir CIDCA 8348 and JCM 5818 were grown in a 1/2 dilution of MRS broth supplemented with Cd(NO3)2 ranging 0 to 1 mM. Growth kinetics were followed during 76 h at 30 °C by registering optical density at 600 nm every 4-10 h. The accumulated concentration of cadmium was determined on cultures in the stationary phase by atomic absorption. The viability of a human hepatoma cell line (HepG2) upon exposure to (a) free cadmium and (b) cadmium previously incubated with Lb. kefir strains was evaluated by determining the mitochondrial dehydrogenase activity. Lb. kefir strains were able to grow and tolerate concentrations of cadmium cations up to 1 mM. The addition of cadmium to the culture medium increased the lag time in all the concentrations used. However, a decrease of the total biomass (maximum Absorbance) was observed only at concentrations above 0.0012 and 0.0011 mM for strains CIDCA 8348 and JCM 5818, respectively. Shorter and rounder lactobacilli were observed in both strains upon microscopic observations. Moreover, dark precipitates compatible with intracellular precipitation of cadmium were observed in the cytoplasm of both strains. The ability of Lb. kefir to protect eukaryotic cells cultures from cadmium toxicity was analysed using HepG2 cells lines. Concentrations of cadmium greater than 3×10(-3) mM strongly decreased the viability of HepG2 cells. However, when the eukaryotic cells were exposed to cadmium pre-incubated 1 h with Lb. kefir the toxicity of cadmium was considerably lower, Lb. kefir JCM 5818 being more efficient. The high tolerance and binding capacity of Lb. kefir strains to cadmium concentrations largely exceeding the tolerated weekly intake (TWI) of cadmium for food (2.5 µg per kg of body weight) and water (3 µg/l) addressed to human consumption, is an important added value when thinking in health-related applications.

Food Additives Derived from Fruits and Vegetables for Sustainable Animal Production and Their Impact in Latin America: An Alternative to the Use of Antibiotics.

The production of healthy animal-derived food entails the effective control of foodborne pathogens and strategies to mitigate microbial threats during rearing. Antibiotics have been traditionally employed in animal farming to manage bacterial infections. However, the prohibition of antibiotic growth promoters in livestock farming has brought significant changes in animal production practices. Although antibiotics are now restricted to treating and preventing bacterial infections, their overuse has caused serious public health issues, including antibiotic resistance and the presence of antibiotic residues in food and wastewater. Therefore, sustainable animal production is crucial in reducing the spread of antibiotic-resistant bacteria. Annually, 40-50% of fruit and vegetable production is discarded worldwide. These discards present significant potential for extracting value-added ingredients, which can reduce costs, decrease waste, and enhance the food economy. This review highlights the negative impacts of antibiotic use in livestock farming and stresses the importance of analyzing the challenges and safety concerns of extracting value-added ingredients from fruit and vegetable co-products at an industrial scale. It also explores the current trends in reducing antibiotic use in livestock, with a focus on Latin American contexts. Finally, the suitability of using value-added ingredients derived from fruit and vegetable co-products for animal feeds is also discussed.

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.

The role of culture in the representation of probiotic foods.

Functional foods, and specifically probiotics, are important products present in retail worldwide. Probiotics comprise "live microorganisms that, when administered in adequate amounts, can confer a health benefit on the host". This study aimed to investigate the effect of culture on probiotic foods social representation. A total of 818 consumers from seven countries (Argentina, Brazil, Honduras, Mauritius, Mexico, Peru, and Slovenia) participated in the study. A free word association task was performed with the inductor term "probiotic food," followed by lemmatization, categorization, and prototypical analysis of the social representation. The results indicated that the term health was common in all countries studied, as well as other positive aspects such as benefits, well-being, and functional foods. This study helped to shed light and better understand the role of culture in the social representation of probiotics.

Conformational landscape, photochemistry, and infrared spectra of sulfanilamide.

A combined matrix isolation FTIR and theoretical DFT(B3LYP)/6-311++G(3df,3pd) study of sulfanilamide (SA) was performed. The full conformational search on the potential energy surface of the compound allowed the identification of four different minima, all of them bearing the sulfamide nitrogen atom placed in the perpendicular orientation relatively to the aromatic ring and differing from each other in the orientation of the hydrogen atoms connected to the two nitrogen atoms of the molecule. All conformers were predicted to be significantly populated in the gas phase (at 100 °C, their relative populations were estimated as being 1:0.9:0.3:0.2). However, in agreement with the theoretically calculated low-energy barriers for conformational isomerization, in the low-temperature matrices, only the most stable conformer could be observed, with the remaining forms being converted into this form during matrix deposition (conformational cooling). The unimolecular photochemistry of matrix-isolated SA (in both argon and xenon) was also investigated. Upon broadband UV irradiation (λ > 215 nm), two photofragmentation pathways were observed: the prevalent pathway (A), leading to extrusion of sulfur dioxide and simultaneous formation of benzene-1,4-diamine, which then converts to 2,5-cyclohexadiene-1,4-diimine, and the minor pathway (B), conducting an γ-cleavage plus [1,3] H-atom migration from the sulfamide group to the aromatic ring, which leads to formation of iminosulfane dioxide and aniline, the latter undergoing subsequent phototransformation into cyclohexa-2,5-dien-1-imine. Finally, the crystalline polymorph of SA resulting from warming (265 K) the amorphous solid obtained from fast cooling of the vapor of the compound onto the cold (13 K) substrate of the cryostat was identified spectroscopically, and found to be the γ-crystalline phase, the one exhibiting in average longer H-bonds and an infrared spectrum resembling more that of the low temperature SA glass. Full assignment of the infrared spectra of this crystalline variety as well as of those of the ß-polymorph room temperature crystalline sample and low temperature amorphous state was undertaken with help of theoretical results obtained for the crystallographically relevant dimer of SA.

Use of whey permeate containing in situ synthesised galacto-oligosaccharides for the growth and preservation of Lactobacillus plantarum.

Galacto-oligosaccharides (GOS) are prebiotics that have a beneficial effect on human health by promoting the growth of probiotic bacteria in the gut. GOS are commonly produced from lactose in an enzymatic reaction catalysed by ß-galactosidase, named transglycosylation. Lactose is the main constituent of whey permeate (WP), normally wasted output from the cheese industry. Therefore, the main goal of this work was to optimise the synthesis of GOS in WP using ß-galatosidase from Aspergillus oryzaea. WP and whey permeate enzymatically treated (WP-GOS) were used as culture media of Lactobacillus plantarum 299v. Lb. plantarum 299v attained the stationary phase in approximately 16 h, reaching 3·6 and 4·1×108 CFU/ml in WP and WP-GOS, respectively. The in situ synthesised GOS were not consumed during growth. No significant differences were observed in the growth kinetics of microorganisms in both media. After fermentation, microorganisms were dehydrated by freeze-drying and spray-drying and stored. The recovery of microorganisms after fermentation, dehydration and storage at 4 °C for at least 120 d was above 108 CFU/g. These studies demonstrated that WP is an appropriate substrate for the synthesis of GOS and the obtained product is also adequate as culture medium of Lb. plantarum 299v. The coexistence of GOS and dehydrated viable probiotic microorganisms, prepared using an effluent as raw material, represents the main achievement of this work, with potential impact in the development of functional foods.

Recent Progress in Understanding the Impact of Food Processing and Storage on the Structure-Activity Relationship of Fucoxanthin.

Fucoxanthin, a brown algae carotenoid, has attracted great interest because of its numerous biological activities supported by in vitro and in vivo studies. However, its chemical structure is susceptible to alterations when subjected to food processing and storage conditions, such as heat, oxygen, light, and pH changes. Consequently, these conditions lead to the formation of fucoxanthin derivatives, including cis-isomers, apo-fucoxanthinone, apo-fucoxanthinal, fucoxanthinol, epoxides, and hydroxy compounds, collectively known as degradation products. Currently, little information is available regarding the stability and functionality of these fucoxanthin derivatives resulting from food processing and storage. Therefore, enhancing the understanding of the biological effect of fucoxanthin derivatives is crucial for optimizing the utilization of fucoxanthin in various applications and ensuring its efficacy in potential health benefits. To this aim, this review describes the main chemical reactions affecting the stability of fucoxanthin during food processing and storage, facilitating the identification of the major fucoxanthin derivatives. Moreover, recent advancements in the structure-activity relationship of fucoxanthin derivatives will be critically assessed, emphasizing their biological activity. Overall, this review provides a critical updated understanding of the effects of technological processes on fucoxanthin stability and activity that can be helpful for stakeholders when designing processes for food products containing fucoxanthin.