Recent advances in the enzymatic synthesis of lipophilic antioxidant and antimicrobial compounds.

Due to the increase in the consumption of highly processed food in developed countries, as well as, a growing number of foodborne diseases, exploration of new food additives is an issue focusing on scientific attention and industrial interest. Functional compounds with lipophilic properties are remarkably desirable due to the high susceptibility to the deterioration of lipid-rich food products. This paper in a comprehensive manner provides the current knowledge about the enzymatic synthesis of lipophilic components that could act as multifunctional food additives. The main goal of enzymatic lipophilization of compounds intentionally added to food is to make these substances soluble in lipids and/or to obtain environmentally friendly surfactants. Moreover, lipase-catalyzed syntheses could result in changes in the antioxidant and antimicrobial activities of phenolic compounds, carbohydrates, amino acids (oligopeptides), and carboxylic acids. The review describes also the implementation of a new trend in green chemistry, where apart from simple and uncomplicated chemical compounds, the modifications of multi-compound mixtures, such as phenolic extracts or essential oils have been carried out.

The Emulsifying Properties of Hydrogenated Rosin Xylitol Ester as a Biomass Surfactant for Food: Effect of pH and Salts.

The xylitol ester of hydrogenated rosin (XEHR) was obtained for the first time from biomass-based hydrogenated rosin and xylitol using an environmentally friendly, high-pressure CO2 catalytic synthesis. This compound is intended for use as an emulsifier for food. Analyses by ICP-AES showed the absence of heavy metal residues in the product, such that it met food standards. Fourier transform infrared and nuclear magnetic resonance spectroscopies together with gel permeation chromatography confirmed the successful esterification and the formation of a monoester and diester with molar masses of 427 and 772 g/mol. The emulsification of water/soybean oil mixtures by adding the XEHR was assessed at pH values of 4, 6.86, and 10 and in the presence of NaCl, KCl, MgCl2, and CaCl2. The XEHR was found to act as an emulsifier by reducing the interfacial tension of such mixtures to less than 2 mN/m under all conditions. The highest emulsifying activity index (9.52 m2/g) and emulsifying stability index (94.53%) were obtained after adding MgCl2 (100 mM). Particle size and confocal microscopy showed that the presence of salts gave a more uniform droplet size and a finer emulsion structure. The high viscosities of the emulsions containing salts also suggested a more cohesive oil droplet network.

Dietary exposure assessment of synthetic food colours using analytical concentrations in Korea.

The safety of nine synthetic colour additives approved in Korea were assessed through hazard identification, hazard characterisation, exposure assessment, and risk characterisation. Hazard identification and characterisation were conducted using new risk information based on toxicology data. Exposure assessment calculated the estimated daily intake (EDI) of the nine colours. Finally, the risk was evaluated by comparing the EDIs of the colours with the acceptable daily intake (ADI). 1,114 samples (24 food categories) among a total of 1,454 samples contained colour additives either at a level that was not detectable or up to a quantified maximum of 288 mg kg-1. The likelihood of risk of exposure to all food colours, evaluated by comparing the EDI with the ADI, was less than 0.52% of the ADI for the general population. These results indicate that use of synthetic food colour in Korea is safe and does not result in excessive exposure to any population group.

Antifungal activity of synthetic cowpea defensin Cp-thionin II and its application in dough.

Plant defensins are small, cysteine-rich antimicrobial peptides of the immune system found in several organs during plant development. A synthetic peptide, KT43C, a linear analogue of the native Cp-thionin II found in cowpea seeds, was evaluated for its antifungal potential. It was found that KT43C displayed antifungal activity against Fusarium culmorum, Penicillium expansum and Aspergillus niger. Like native plant defensins, KT43C showed thermostability up to 100 °C and cation sensitivity. The synthetic peptide decreased the fungal growth without inducing morphogenic changes in the fungal hyphae. Non-inhibitory concentrations of the peptide induced permeabilization of the fungal membrane. In addition, high concentrations of KT43C induced the production of reactive oxygen species in the granulated cytoplasm. To investigate potential applications, the peptide was used as an additive in the preparation of dough which did not contain yeast. This peptide delayed the development of fungal growth in the dough by 2 days. Furthermore, KT43C did not induce red blood cell lysis up to a concentration of 200 µg.ml-1. These results highlight the potential for the use of synthetic antimicrobial defensins for shelf-life extension of food products.

Simple and efficient sustainable semi-synthesis of oleacein [2-(3,4-hydroxyphenyl) ethyl (3S,4E)-4-formyl-3-(2-oxoethyl)hex-4-enoate] as potential additive for edible oils.

A simple and very environmental friendly microwave assisted method to produce oleacein in good yield starting from the easily available oleuropein is here presented. The methodology is proposed to produce the appropriate amount of hydroxytyrosol derivatives to enrich a commercial oil for an oil which provides beneficial effects on the human health.

MyD88-dependent pro-interleukin-1ß induction in dendritic cells exposed to food-grade synthetic amorphous silica.

BACKGROUND: Dendritic cells (DCs) are specialized first-line sensors of foreign materials invading the organism. These sentinel cells rely on pattern recognition receptors such as Nod-like or Toll-like receptors (TLRs) to launch immune reactions against pathogens, but also to mediate tolerance to self-antigens and, in the intestinal milieu, to nutrients and commensals. Since inappropriate DC activation contributes to inflammatory diseases and immunopathologies, a key question in the evaluation of orally ingested nanomaterials is whether their contact with DCs in the intestinal mucosa disrupts this delicate homeostatic balance between pathogen defense and tolerance. Here, we generated steady-state DCs by incubating hematopoietic progenitors with feline McDonough sarcoma-like tyrosine kinase 3 ligand (Flt3L) and used the resulting immature DCs to test potential biological responses against food-grade synthetic amorphous silica (SAS) representing a common nanomaterial generally thought to be safe. RESULTS: Interaction of immature and unprimed DCs with food-grade SAS particles and their internalization by endocytic uptake fails to elicit cytotoxicity and the release of interleukin (IL)-1α or tumor necrosis factor-α, which were identified as master regulators of acute inflammation in lung-related studies. However, the display of maturation markers on the cell surface shows that SAS particles activate completely immature DCs. Also, the endocytic uptake of SAS particles into these steady-state DCs leads to induction of the pro-IL-1ß precursor, subsequently cleaved by the inflammasome to secrete mature IL-1ß. In contrast, neither pro-IL-1ß induction nor mature IL-1ß secretion occurs upon internalization of TiO2 or FePO4 nanoparticles. The pro-IL-1ß induction is suppressed by pharmacologic inhibitors of endosomal TLR activation or by genetic ablation of MyD88, a downstream adapter of TLR pathways, indicating that endosomal pattern recognition is responsible for the observed cytokine response to food-grade SAS particles. CONCLUSIONS: Our results unexpectedly show that food-grade SAS particles are able to directly initiate the endosomal MyD88-dependent pathogen pattern recognition and signaling pathway in steady-state DCs. The ensuing activation of immature DCs with de novo induction of pro-IL-1ß implies that the currently massive use of SAS particles as food additive should be reconsidered.

Binding of λ-carrageenan (a food additive) to almond cystatin: An insight involving spectroscopic and thermodynamic approach.

Carrageenan is a high molecular weight linear sulphated polysaccharide, primarily used in food industry as gelling, thickening, and stabilizing agent. Almond milk prepared from almonds is low in fat, but high in antioxidants, energy, proteins, lipids and fibre. Purified almond cystatin was incubated with increasing concentrations of carrageenan at 25°C for different time interval and significant loss in inhibitory activity was observed. Interaction between carrageenan and cystatin resulted in complex formation as depicted by the decrease in fluorescence intensity with increase in the concentration of carrageenan. Stern-volmer analysis of fluorescence quenching data showed binding constant to be 1.84±0.20×104M-1 and number of binding sites close to unity. These results were further confirmed by supporting results obtained in UV-vis spectroscopy. FTIR analysis shows significant shift in the peak intensity and this change clearly depict change in the structure of cystatin from that of α helix to ß-sheet. CD spectra further confirmed the structural transition of the cystatin from α helix to ß-sheet structure on interaction with increased concentrations of carrageenan. The contributing thermodynamic parameters were determined by ITC. The negative ΔH° and positive TΔS° values suggest involvement of electrostatic forces and hydrophobic interaction in the formation of the λ-carrageenan-cystatin complex.

Feed additive production by fermentation of herb Polygonum hydropiper L. and cassava pulp with simultaneous flavonoid dissolution.

Fermentation of herb Polygonum hydropiper L. (PHL) and cassava pulp (CP) for feed additive production with simultaneous flavonoid dissolution was investigated, and a two-stage response surface methodology (RSM) based on Plackett-Burman factorial design (PB design) was used to optimize the flavonoid dissolution and protein content. Using the screening function of PB design, four different significant factors for the two response variables were acquired: factors A (CP) and B (PHL) for the flavonoid dissolution versus factors G (inoculum size) and H (fermentation time) for protein content. Then, two RSMs were used sequentially to improve the values of the two response variables separately. The mutual corroboration of the experimental results in the present study confirmed the validity of the associated experimental design. The validation experiment showed a flavonoid dissolution rate of 94.00%, and a protein content of 18.20%, gaining an increase in 21.20% and 199.10% over the control, respectively. The present study confirms the feasibility of feed additive production by Saccharomyces cerevisiae with CP and PHL and simultaneous optimization of flavonoid dissolution and protein content using a two-stage RSM.

Present Global Situation of Amino Acids in Industry.

At present, amino acids are widely produced and utilized industrially. Initially, monosodium glutamate (MSG) was produced by extraction from a gluten hydrolysate. The amino acid industry started using the residual of the lysate. The discovery of the functions of amino acids has led to the expansion of their field of use. In addition to seasoning and other food use, amino acids are used in many fields such as animal nutrients, pharmaceuticals, and cosmetics. On the other hand, the invention of the glutamate fermentation process, followed by the development of fermentation methods for many other amino acids, is no less important. The supply of these amino acids at a low price is very essential for their industrial use. Most amino acids are now produced by fermentation. The consumption of many amino acids such as MSG or feed-use amino acids is still rapidly increasing.

Development, physiochemical characterization and forming mechanism of Flammulina velutipes polysaccharide-based edible films.

Edible films of Flammulina velutipes polysaccharide were prepared and characterized in terms of rheological, optical, morphologic, mechanical and barrier properties to evaluate their potential application in food packaging. Results suggested that FVP film prepared by the solution of 1:150 (w/v) had the optimal mechanical property, smooth and uniform surface, and good barrier property to water (37.92±2.00gmm/m(2)hkPa) and oxygen (37.92±2.01meq/kg). The capacity of film-formation might be related to inter-molecular and intra-molecular hydrogen bonds of FVP and formation of ß-glycosidic bonds during the process of film-formation. These findings will contribute to a theoretical basis for the development of FVP film in food packaging.

Synthesis and characterization of glucosyl stevioside using Leuconostoc dextransucrase.

Glucosyl stevioside was synthesized via transglucosylation by dextransucrase from Leuconostoc citreum KM20 (LcDexT), forming α-d-glucosyl stevioside. A production yield of 94% was reached after 5days of LcDexT reaction at 30°C. Glucosyl stevioside induced a 2-fold improved quality of taste and sweetness, compared to stevioside. After 15days of storage at 25°C, 98% of glucosyl stevioside in an aqueous solution was present in a soluble form, compared to only 11% for stevioside or rebaudioside A. Furthermore, glucosyl stevioside exhibited a similar or improved stability in commercially available soft drinks, when compared to stevioside and rebaudioside A. These results suggest that glucosyl stevioside could serve as a highly pure and stable sweetener in soft drinks.

Preparation of thermally stable microcapsules with a chitosan-silica hybrid.

Addition of microcapsules with a high dielectric constant and low specific heat capacity to a battered layer was designed to create a higher temperature in the crust than in the prefried fish nuggets to prevent the water vapor in the fish nuggets from migrating to the crust during microwave heating. Therefore, chitosan-silica hybrids and soybean oil were utilized to prepare the shell and core of the thermally stable microcapsules (MC(CS)), respectively. The MC(CS) were prepared by sol-gel coacervation from an oil-in-water emulsion. The sodium silicate was hydrolyzed and coacervated through polymerization for 24 h at pH 5. The zeta potential analysis indicated that chitosan with a positive charge and silica with a negative charge interacted through electrostatic attraction to form a hybrid shell. The volume mean particle size and encapsulation efficiency of the MC(CS) were 9.6 ± 0.2 µm and 75.6% ± 1.3%, respectively, when oil/chitosan = 0.2 and chitosan/silica = 0.5 (w/w). In addition to H-bonding and electrostatic attraction, Si-O-N bonds were formed between chitosan and silica. Dehydration of the bound water in the MC(CS) was observed in the range of 25 to 250 °C in the differential scanning calorimetry thermal analysis, with the lack of apparent thermal peaks indicating its high thermal stability. The decrease of force to cut the crust observed by texture analysis as well as the increase of hedonic score by consumer acceptance test revealed the addition of 1% MC(CS) significantly improved the crispness of the crust in the microwave-reheated nuggets.

Acidic organic compounds in beverage, food, and feed production.

Organic acids and their derivatives are frequently used in beverage, food, and feed production. Acidic additives may act as buffers to regulate acidity, antioxidants, preservatives, flavor enhancers, and sequestrants. Beneficial effects on animal health and growth performance have been observed when using acidic substances as feed additives. Organic acids could be classified in groups according to their chemical structure. Each group of organic acids has its own specific properties and is used for different applications. Organic acids with low molecular weight (e.g. acetic acid, lactic acid, and citric acid), which are part of the primary metabolism, are often produced by fermentation. Others are produced more economically by chemical synthesis based on petrochemical raw materials on an industrial scale (e.g. formic acid, propionic and benzoic acid). Biotechnology-based production is of interest due to legislation, consumer demand for natural ingredients, and increasing environmental awareness. In the United States, for example, biocatalytically produced esters for food applications can be labeled as "natural," whereas identical conventional acid catalyst-based molecules cannot. Natural esters command a price several times that of non-natural esters. Biotechnological routes need to be optimized regarding raw materials and yield, microorganisms, and recovery methods. New bioprocesses are being developed for organic acids, which are at this time commercially produced by chemical synthesis. Moreover, new organic acids that could be produced with biotechnological methods are under investigation for food applications.

Synthesis and evaluation of odour-active methionyl esters of fatty acids via esterification and transesterification of butter oil.

Methionol-derived fatty acid esters were synthesised by both chemical and lipase catalysed esterification between fatty acids and methionol. Beneficial effects of both methods were compared qualitatively and quantitatively by GC-MS/GC-FID results. And the high acid and heat stability of our designed methionyl esters meet the requirement of the food industry. Most importantly, the sensory test showed that fatty acid carbon-chain length had an important effect on the flavour attributes of methionyl esters. Moreover, through Lipozyme TL IM-mediated transesterification, valuable methionol-derived esters were synthesised from the readily available natural material butter oil as the fatty acid source. The conversion of methionol and yield of each methionyl ester were also elucidated by GC-MS-FID.

Antioxidant activity of essential oils.

Essential oils (EOs) are liquid mixtures of volatile compounds obtained from aromatic plants. Many EOs have antioxidant properties, and the use of EOs as natural antioxidants is a field of growing interest because some synthetic antioxidants such as BHA and BHT are now suspected to be potentially harmful to human health. Addition of EOs to edible products, either by direct mixing or in active packaging and edible coatings, may therefore represent a valid alternative to prevent autoxidation and prolong shelf life. The evaluation of the antioxidant performance of EOs is, however, a crucial issue, because many commonly used "tests" are inappropriate and give contradictory results that may mislead future research. The chemistry explaining EO antioxidant activity is discussed along with an analysis of the potential in food protection. Literature methods to assess EOs' antioxidant performance are critically reviewed.

Structure and physicochemical properties of octenyl succinic anhydride modified starches: a review.

Starches modified with octenyl succinic anhydride (OSA) have been used in a range of industrial applications, particularly as a food additive, for more than half a century. Interest in these products has grown in recent years as a result of new methods and applications becoming available. Due to a combination of OSA's hydrophobic and steric contribution and starch's peculiar highly branched macromolecular structure, these starch derivatives display useful stabilizing, encapsulating, interfacial, thermal, nutritional and rheological properties. We review the synthesis procedures, structural characterization methods and physico-chemical properties, and the influences of the botanical origins and structural parameters of OSA starches on physico-chemical properties. A better understanding of these features has the potential to lead to products with targeted macromolecular structures and optimized properties for specific applications.

2-O-Methyl- and 3,6-di-O-methyl-cellulose from natural cellulose: synthesis and structure characterization.

For the first time, 2-O-methyl- (2MC) and 3,6-di-O-methyl-cellulose (36MC) were synthesized via 3-O-allyl- and 3-O-methyl-cellulose, respectively. Position 6 of 3-O-allyl- and 3-O-methyl-cellulose was protected with the 4-methoxytrityl groups. The reaction time and temperature were optimized to achieve a high regioselectivity at C-6 and to prevent the introduction of the 4-methoxytrityl group at C-2 of the polymer. It was found that the substituent at C-3 of 3-O-functionalized celluloses influenced the reactivity of the hydroxyl group at C-6. The structure was characterized by means of (1)H and (13)C NMR spectroscopy of the acetates of 2MC and 36MC. 2MC and 36MC were soluble in water and did not show thermoreversible gelation.

Sodium salt of starch octenylsuccinate as an emulsifier in "light" type mayonnaises.

INTRODUCTION: The E 1450 sodium salt of starch octenylsuccinate which exhibits emulsifying properties is used as food additive and is also recommended as yolk replacer in the process of mayonnaise production. Commercial E 1450 preparations reveal excellent functional properties in mayonnaise production. However, sodium salt of starch octenylsuccinate produced in the course of the suspension process (as well as the product of its hydrolysis in a membrane reactor), despite high surface activity, is unsuitable for this purpose. Therefore, a hypothesis was put forward that the cause of the unsuitability of these preparations for mayonnaise production is their improper profile of molecular mass distribution and the objective of this study was to verify the above thesis. MATERIAL AND METHODS: E 1450 preparations of different degree of substitution obtained alternately by means of reactive extrusion or enzymatic hydrolysis preceded by esterification in suspension were investigated. Preparations were characterised physico-chemically by determining the degree of substitution, viscosity, emulsifying activity index (EAI) and their capability to stabilise model emulsions (ME). Their molecular mass distribution profiles were determined and their suitability for the manufacture of low-fat mayonnaises was assessed. These investigations were also carried out for mixtures of preparations obtained as a result of a reactive extrusion and hydrolysis of the ester obtained during the suspension process. RESULTS: Despite the fact that the preparations obtained in suspension were characterised by 100% values of the ES parameter, all attempts to manufacture with their assistance of mayonnaise by way of a simple substitution in the formulation of dried egg yolk by E 1450 starch failed. Similarly, attempts to manufacture mayonnaise using any of the preparations obtained by means of reactive extrusion or enzymatic hydrolysis of the reaction product in suspension also ended in failure. The only successful solution was the application of equilibrium mixtures of E 1450 preparations obtained by way of reactive extrusion with a hydrolisate. Table 2 collates texture parameters of the obtained mayonnaises. CONCLUSION: The performed investigations fully corroborated the correctness of the proposed hypothesis that the suitability of the starch octenylsuccinate sodium salt as an emulsifier for low-fat mayonnaises is associated with the appropriately high polydispersity of this polymer.

A new, simple method for the production of meat-curing pigment under optimised conditions using response surface methodology.

The production of cured meat pigment using nitrite and ascorbate in acidic conditions was evaluated. HCl, ascorbate and nitrite concentrations were optimised at three levels using the response surface method (RSM). The effects of process variables on the nitrosoheme yield, the wavelength of maximum absorbance (λ(max)), and L*, a* and b* values were evaluated. The response surface equations indicate that variables exerted a significant effect on all dependent factors. The optimum combinations for the reaction were HCl=-0.8, ascorbate=0.46 and nitrite=1.00 as coded values for conversion of 1mM hemin to nitrosoheme, by which a pigment yield of 100%, which was similar to the predicted value of 99.5%, was obtained. Likewise, the other parameters were not significantly different from predicted values as the λ(max), L*, a* and b* values were 558 nm, 47.03, 45.17 and 17.20, respectively. The structure of the pigment was identified using FTIR and ESI/MS.