Model Food System Research Articles

Utilization of Carob Fruit as Sources of Phenolic Compounds with Antioxidant Potential: Extraction Optimization and Application in Food Models.

The goal of this study was to explore the potential of carob extracts to act as lipid inhibitors in model food systems. First, the extraction efficacy of fourteen solvents on the phenolic and flavonoid contents as well as on the antioxidant activity was assessed. Results showed that the phenolic composition and antioxidant activity of the extracts were strongly affected by solvents. Subsequently, the antioxidant potential of the most promising extracts (water, methanol, acidic acetone, and acetone–water) against four model food systems were evaluated. The acidic acetone extract had the highest antioxidant activity (70.3 ± 5.3%) in the β-carotene-linoleic acid system, followed by the acetone–water extract (62.1 ± 4.9%). Both extracts significantly prevented the lipid oxidation in sunflower oil and cooked comminuted pork; the inhibition activity at the end of storage period was 36.7–50.5% and 17.4–24.8%, respectively. A reduction of 49.5–54.8% in the formation of dienes in the oil-in-water emulsion was also found. The inhibitory effect of methanolic and aqueous extracts was significantly lower. Qualitative and quantitative variations in extracts are responsible for this antioxidant behavior in food systems. Gallic acid, myrecetin, rutin, and catechin are the main components of the extracts while myricetin and quercetin play an essential role in the antioxidant activity, according to the biochromatograms.

Quality retention and shelf life extension of fresh beef using Lepidium sativum seed mucilage-based edible coating containing Heracleum lasiopetalum essential oil: an experimental and modeling study.

The instability and strong flavor or odor of essential oils (EO) limit their direct incorporation into food products. In this study, the antioxidant and antimicrobial Heracleum lasiopetalum essential oil (HLEO) was added to Lepidium sativum seed mucilage (LSSM) solution at four concentrations (0, 0.5, 1, and 1.5%) to develop a novel edible coating and expand its food application. HLEO-loaded LSSM coating was then used to improve the shelf life and quality of beef as a model food system. The coated and control beef samples were periodically analyzed for physicochemical analysis, microbiological, and sensory characteristics over a period of 9days at 4°C. The HLEO-enriched LSSM coating, particularly 1.5% loaded one resulted in a significant (p < 0.05) increase in oxidative and microbiological stability and overall acceptance of the beef samples, compared to the control counterpart. HLEO-loaded LSSM coating, therefore, provides a promising alternative to preserve the meat products under cold storage.

Antioxidant Activity Evaluation of Tocored through Chemical Assays, Evaluation in Stripped Corn Oil, and CAA Assay

Abstractγ‐Tocopherol‐5,6‐quinone (tocored) is a crucial oxidized product of γ‐tocopherol (γ‐T) found in edible oil. Previously published studies on antioxidant activity (AOA) of tocored are not consistent. This study aims to monitor its AOA comprehensively through chemical assays (1,1‐diphenyl‐2‐picrylhydrazyl [DPPH] and ferric reducing antioxidant power [FRAP]), antioxidant evaluation in a food model system (stripped corn oil), and cellular antioxidant activity (CAA) assay, which would reasonably widen the knowledge of the AOA of γ‐T and tocored. In both DPPH and FRAP assays, tocored shows less AOA than γ‐T. Results of chemical properties in the Schaal oven test show that tocored possesses better AOA than γ‐T. Correlation coefficients of γ‐T and tocored between peroxide and K234 or p‐AnV are 0.8784–0.9875 and 0.8716–0.9879, respectively. The CAA assay also shows that tocored possesses better cellar AOA than γ‐T, with an EC50 at 21.55 µg mL−1. Drawing conclusions from the results from chemical assays, evaluation in stripped corn oil, and CAA assay, tocored is verified as a potent antioxidant in edible vegetable oils compared to γ‐T.Practical Applications: The present work widens the knowledge of antioxidant activity of tocored and gamma‐tocopherol, and contributes to the understanding of existing antioxidant activity when gamma tocopherol is depleted when edible oils are in storage and processing processes.

Efficient and prolonged antibacterial activity from porous PLGA microparticles and their application in food preservation.

Simple addition of a minute quantity of non-toxic mustard oil in water/oil/water (W/O/W) double emulsion led to a porous morphology at the surface as well as in the interior of the biodegradable PLGA (Poly(l-lactide-co-glycolide)) microparticles. An attempt was made to understand the mechanism of pore formation by analyzing optical micrographs and SEM images in addition to solution viscosity of organic phase and interfacial tension values between organic and aqueous phases. The origin of surface porosity was thought to come from the inclusion of inner water droplet, stabilized by heteroaggregation of mustard oil and PLGA chains along with PVA (polyvinyl alcohol), to the solidifying polymer skin. The surface pores did not arise in absence of mustard oil. The encapsulation and release of antibacterial active (benzoic acid) from porous PLGA particles was studied in PBS buffer (pH7) at 37°C for 60days. The release profiles were well-controlled in nature, and found to be influenced by surface porosity of the particles that can be manipulated by varying the amount of mustard oil. The release mechanism can well be explained with the help of power law model. Strikingly, in liquid medium, porous particles were found completely suppressing the growth of Escherichia coli and Staphylococcus aureus for a prolonged period of 60days. The strong antimicrobial activity (100% inhibition of bacterial growth) in porous particles can be linked to the enhanced surface area due to the formation of micro/nano pores which accelerate the hydrolytic degradation of PLGA to release lactic acid/glycolic acid (antibacterial) in addition to encapsulated antibacterial (benzoic acid). In a food model system, the shelf life of the water melon juice was also found to be enhanced by suppressing the growth of the natural microbes in comparison to control.

Effects of electrotechnologies on enzymes in foods and food model systems

Electrotechnologies gained increased popularity as non-thermal processing of foods as they offer many advantages over conventional thermal processing. These technologies effectively inactivate microorganisms, enhance the processing efficacy at lower treatment intensity (e.g. pressing, pre-treatment for drying, extraction etc.) with preservation of nutritional, functional and sensory characteristics of processed foods. Moreover, these technologies can be applied for targeted and controlled enzymatic treatments. Structural and conformational changes under these treatments may influence enzymatic inactivation, but also activate enzymes or enhance their activity. Therefore, the enzyme characteristics and treatment conditions could be finely tuned toward desirable properties and effects in food production and processing.

Antimicrobial, Antioxidant, and Immunomodulatory Properties of Essential Oils: A Systematic Review.

Essential oils (EOs) are a mixture of natural, volatile, and aromatic compounds obtained from plants. In recent years, several studies have shown that some of their benefits can be attributed to their antimicrobial, antioxidant, anti-inflammatory, and also immunomodulatory properties. Therefore, EOs have been proposed as a natural alternative to antibiotics or for use in combination with antibiotics against multidrug-resistant bacteria in animal feed and food preservation. Most of the results come from in vitro and in vivo studies; however, very little is known about their use in clinical studies. A systematic and comprehensive literature search was conducted in PubMed, Embase®, and Scopus from December 2014 to April 2019 using different combinations of the following keywords: essential oils, volatile oils, antimicrobial, antioxidant, immunomodulation, and microbiota. Some EOs have demonstrated their efficacy against several foodborne pathogens in vitro and model food systems; namely, the inhibition of S. aureus, V. cholerae, and C. albicans has been observed. EOs have shown remarkable antioxidant activities when used at a dose range of 0.01 to 10 mg/mL in cell models, which can be attributed to their richness in phenolic compounds. Moreover, selected EOs exhibit immunomodulatory activities that have been mainly attributed to their ability to modify the secretion of cytokines.

Millet phenolics as natural antioxidants in food model systems and human LDL/VLDL cholesterol &lt;em&gt;in vitro&lt;/em&gt;

Dehulled grain flour of finger millet (Eleusine coracana), proso millet (Panicum miliaceum) and foxtail millet (Setaria italica) and phenolic extracts of millet hulls were evaluated for ability to inhibit lipid oxidation in several food model systems, namely cooked comminuted pork and fish, roasted peanut butter and gingelly oil. Food samples were kept for 14 days with added millet hull extracts and dehulled grain flours. The percentage inhibition of production of thiobarbituric acid reactive substances (TBARS) during storage was determined. Inhibitory activities of phenolic extracts of finger millet dehulled grain and finger millet foods, namely, Rotti, Pittu, Halapa, Thalapa and porridge, against human very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) oxidation were determined by measuring the production level of conjugated dienes (CD) in vitro. Finger millet had higher phenolic content and antioxidant activities compared to the respective proso and foxtail millet samples. Finger millet hull extracts exhibited the highest inhibition of lipid peroxidation in food model systems. The maximum percentage inhibition of TBARS in pork, fish, and peanut with added finger millet hull extracts were observed at days 3, 7, 5, and 14, respectively. The percentage inihibition of TBARS in cooked pork and fish with added millet hull extracts ranged from 4.4 to 12.8% and 63 to 77%, respectively at the end of the second week. Millet grains and desolventized millet phenolic extracts can act as natural sources of antioxidants at different degrees in pork, fish, peanut and gingelly oil to prevent lipid oxidation during storage.

Studying the operation of innovative equipment for thermomechanical treatment and dehydration of food raw materials

The paper reports results of investigating innovative equipment for the integrated processing of food raw materials, which would make it possible to implement the local energy influence directly on the particles of a dispersed material, the near-boundary layer, the moisture retained in the product's solution or capillaries. The analysis of food raw materials processing techniques has been performed, their benefits and shortcomings have been identified. It was found that product quality, energy consumption and cost are mainly determined at the stages of thermal processing, drying. We have examined innovative equipment based on rotary thermosiphons for evaporating food non-Newtonian liquids. An experimental bench has been designed, and the procedure for studying the hydrodynamics of condensate motion in condensers of rotary thermosyphons of various structures has been devised. The experimental bench represents a model of the device with a rotary thermosiphon made of glass. The result of our study is the established rotational frequency, at which a condensate is locked by the centrifugal force for a branched condenser. Results from visualization of vapor-condensate movement have been presented. The innovative equipment for the evaporation of food non-Newtonian liquids under SHF radiation conditions has been investigated. Experiments involved food products and model systems. We have determined the degree of an increase in the concentration of non-aquatic components. Evaporation rate under conditions of SHF radiation is almost constant. The innovative equipment for drying fruit- and vegetable-based slices under conditions of IR radiation has been examined. An experimental bench has been designed and the research procedure has been devised. We have proposed the structure of an equation for calculating the mass transfer coefficient. The database of experimental findings has been generalized in the equation by similarity numbers. The equation makes it possible to calculate a mass transfer coefficient with error within ±15 %. The influence of IR radiation power on the kinetics of the process of drying fruit and vegetable slices has been determined. We have compared experimental data on slice drying under conditions of SHF and IR radiation

Simultaneous use of low methylesterified citrus pectin and EDTA as antioxidants in linseed/sunflower oil-in-water emulsions

In view of reducing synthetic antioxidants in emulsion-based food products, such as ethylene diamine tetraacetic acid (EDTA), this study aimed to investigate the simultaneous use of low methylesterified citrus pectin and EDTA to inhibit lipid oxidation as a consequence of their capacities to chelate Fe2+. EDTA was found to be more effective in reducing lipid oxidation in oil-in-water (o/w) emulsions compared to pectin, probably due to its higher and stronger Fe2+ binding capacity. Moreover, pectin induced emulsion physical instability by depletion or bridging flocculation for 0.1% (w/v) pectin, and coalescence for 1% (w/v) pectin. A combination of low methylesterified pectin and EDTA in the o/w emulsions revealed a reduction of the antioxidant capacity of the individual compounds. In other words, no cooperative effect between pectin and EDTA to reduce the lipid oxidation was observed in this study. Although the reduction of EDTA concentrations in emulsions seems challenging, it is advised to conduct more fundamental research on pectin-EDTA interactions in model and real food systems.

Effectiveness of a novel UV light emitting diode based technology for the microbial inactivation of Bacillus subtilis in model food systems

The objective of this study was to assess the effectiveness of a novel UV multiwavelength light emitting diode (LED) based technology for the inactivation of B. subtilis in two model food systems. The LED based system was used to treat B. subtilis bacterial cultures using various combinations of UV wavelengths (285, 365, 405, 285/365, 285/405, 365/405, 285/365/405 nm) for two treatment durations (5 & 10 min). Bacterial enumerations, post-treatment analysis and SEM imaging were carried out. UV treatment at 285 nm was found to be the most efficient individual wavelength for inactivation resulting in >6 log10 reductions. Treatments at other wavelengths investigated also resulted in bacteriostatic effects. Synergistic effects were observed for treatment at a 285/405 nm combination in one model system. Growth kinetics were investigated using a modified Gompertz model and model fit was assessed by root mean squared error, accuracy factor and bias factor. Experimental data showed good fit with the model employed with RMSE values ranging from 0.01 × 10−2 to 1.367 × 10−2 for 5 min treatment, and 0.01 × 10−2 to 0.210 × 10−2 for 10 min treatment. Multivariate analysis was also carried out using principal component analysis and explained 100% of the variation observed using 3 principal components. This study shows that UV-LED technology is effective as a bactericidal and bacteriostatic technology depending on the wavelength used.

New Functional Ingredients Based on Microencapsulation of Aqueous Anthocyanin-Rich Extracts Derived from Black Rice (Oryza sativa L.).

The aqueous anthocyanin-rich extract derived from black rice (Oryza sativa L.) was encapsulated by freeze drying using milk proteins and peptides as coating materials. The molecular modelling approach indicated that all major casein fractions and whey proteins were able to bind at least one anthocyanin molecule. The hydrophobic interactions and hydrogen bonding across the interfaces appeared to be mainly responsible for the stabilizations of the complexes formed between the coating material and bioactive compounds. Two dark purple colored powders, differentiated by the ratio of the encapsulation materials used, rich in phytochemicals were obtained, with an encapsulation efficiency of up to 99%. The powders were tested for antioxidant activity, cytocompatibility, and thermal stability. The morphological structure of the powders highlighted the presence of encapsulated anthocyanins. Both powders showed a remarkable antioxidant activity of about 46 mM Trolox/g D.W., and cytocompatibility on the L929 fibroblast culture. At certain concentrations, both powders stimulated cell proliferation. The powders showed a good thermal stability between 75 and 100 °C for 15 min. The powders were tested in a food model system and checked for stability of phytochemicals during storage. The added value of the powders was demonstrated throughout the antioxidant activity, which remained unchanged during storage.

Effect of microencapsulation on antioxidant and antifungal properties of aqueous extract of pomegranate peel.

The aqueous extract of pomegranate (Punica granatum L.) peel compounds was freeze-dried (FDPOPx) and encapsulated using two wall forming components at two concentrations (maltodextrin: MDX and β-cyclodextrin: βCDX; 5 and 10%) with a mass ratio of 1:5 (extract/wall material). Different properties of the encapsulated powders (bioactive components, physicochemical and morphological properties) and storage stability of prepared microcapsules were evaluated during 42days of storage at a different relative humidity (52 and 75%) and temperatures (4 and 25°C). Encapsulated powder with βCDX-10% had the highest total phenolic compounds (TPC: 58.78mg GA/g) and antioxidant capacity [FRAP: 1414.76μmol Fe2+/g and DPPH assay (RSA): 77.83%] among other wall materials. The amounts of TPC and their antioxidant capacity decreased during the 42days of storage. However, the highest TPC was observed in the freeze-dried MDX-10% % encapsulated powder at 4°C storage temperature and 52% relative humidity with a half-life (t1/2) of 81days, the reaction rate constant (k) of 0.85 × 10-2min-1 and the glass transition temperature of 69.73°C. In addition, the polyphenolic extracts (both free and encapsulated) were able to control the growth of yeasts and molds, and maintaining the sensory properties of cupcakes as the model food system. The lowest growth after 9days of storage of cupcake was observed in samples prepared with 1.5% of microencapsulated powder (MDX-10%) which was equivalent to the effect of the chemical preservative potassium sorbate.

Effect of ultrasound on the techno-functional properties of food components/ingredients: A review.

Ultrasound (US) has been used in many food systems and model systems, such as starch, whey protein concentrates and soy, to modify their chemical and techno-functional properties. At present, the use of ultrasound has yielded diverse results, ranging from potentiating the technological and functional properties of various foods to different operating conditions. Similarly, the results that were obtained vary according to the ultrasonic equipment used and the power, frequency and times of sonication, as well as the characteristics of the food system used. However, not all results have been favourable because US can cause damage to the structure of some food components, such as starch, and affect the technological and functional properties of the food. In the literature, there is little research on the effect of sonication on fibre; this gap in the literature is worrisome because fibre is found in a wide variety of foods and provides health benefits. Such research would represent an opportunity for researchers to make use of this technology for the generation of knowledge and improve the techno-functional properties in fibre, which could benefit the human population and the food industry. In this review, we present current results obtained with US in different treatments affecting processes of strong importance in the food industry, emphasizing the effects in the different model systems.

Isolating the effect of fat content on Listeria monocytogenes growth dynamics in fish-based emulsion and gelled emulsion systems

The influence of food matrix fat content on growth kinetics of bacteria is quite complex and, thus far, not fully elucidated, with different studies reporting contradictory results. Since results in studies involving real food products are possibly influenced by variations in compositional and physicochemical properties, there is a need for systematic studies in artificial food model systems among which the influence of fat content is effectively isolated. In this study, the isolated effect of a gradual increase in fat content, in the range of 1–20% (w/w), on the growth dynamics of Listeria monocytogenes in fish-based emulsion and gelled emulsion model systems was investigated at 4, 7 and 10 °C. Growth parameters estimated by the Baranyi and Roberts model were compared among the different model systems. Overall, an increase from 1 to 5% fat resulted in a significant reduction of the lag phase duration λ in both model systems at all studied temperatures, while a further increase in fat content did not significantly affect λ. The relationship between the fat content (%) and the maximum specific growth rate μmax was more complex, following the same trends for both emulsions and gelled emulsions and tested temperatures, i.e., (i) μmax was higher at 5% than at 1% fat, (ii) μmax was lower at 10% than at 5% fat, (iii) μmax at 20% fat was higher than or equal to μmax at 10% fat, and (iv) μmax was the highest at 5% fat. Based on these experiments, fundamental knowledge was provided which could lead to the development of food matrix-related factors describing the influence of fat content in future predictive modeling tools which include food microstructural elements. Such models could increase the accuracy of the shelf-life estimation for fat-containing foods, in turn resulting in improved food safety.

Food Microstructure and Fat Content Affect Growth Morphology, Growth Kinetics, and Preferred Phase for Cell Growth of Listeria monocytogenes in Fish-Based Model Systems.

Food microstructure significantly affects microbial growth dynamics, but knowledge concerning the exact influencing mechanisms at a microscopic scale is limited. The food microstructural influence on Listeria monocytogenes (green fluorescent protein strain) growth at 10°C in fish-based food model systems was investigated by confocal laser scanning microscopy. The model systems had different microstructures, i.e., liquid, xanthan (high-viscosity liquid), aqueous gel, and emulsion and gelled emulsion systems varying in fat content. Bacteria grew as single cells, small aggregates, and microcolonies of different sizes (based on colony radii [size I, 1.5 to 5.0 μm; size II, 5.0 to 10.0 μm; size III, 10.0 to 15.0 μm; and size IV, ≥15 μm]). In the liquid, small aggregates and size I microcolonies were predominantly present, while size II and III microcolonies were predominant in the xanthan and aqueous gel. Cells in the emulsions and gelled emulsions grew in the aqueous phase and on the fat-water interface. A microbial adhesion to solvent assay demonstrated limited bacterial nonpolar solvent affinities, implying that this behavior was probably not caused by cell surface hydrophobicity. In systems containing 1 and 5% fat, the largest cell volume was mainly represented by size I and II microcolonies, while at 10 and 20% fat a few size IV microcolonies comprised nearly the total cell volume. Microscopic results (concerning, e.g., growth morphology, microcolony size, intercolony distances, and the preferred phase for growth) were related to previously obtained macroscopic growth dynamics in the model systems for an L. monocytogenes strain cocktail, leading to more substantiated explanations for the influence of food microstructural aspects on lag phase duration and growth rate.IMPORTANCEListeria monocytogenes is one of the most hazardous foodborne pathogens due to the high fatality rate of the disease (i.e., listeriosis). In this study, the growth behavior of L. monocytogenes was investigated at a microscopic scale in food model systems that mimic processed fish products (e.g., fish paté and fish soup), and the results were related to macroscopic growth parameters. Many studies have previously focused on the food microstructural influence on microbial growth. The novelty of this work lies in (i) the microscopic investigation of products with a complex composition and/or structure using confocal laser scanning microscopy and (ii) the direct link to the macroscopic level. Growth behavior (i.e., concerning bacterial growth morphology and preferred phase for growth) was more complex than assumed in common macroscopic studies. Consequently, the effectiveness of industrial antimicrobial food preservation technologies (e.g., thermal processing) might be overestimated for certain products, which may have critical food safety implications.

Effect of microstructure and initial cell conditions on thermal inactivation kinetics and sublethal injury of Listeria monocytogenes in fish-based food model systems

The development of more accurate predictive models that describe the microbial kinetics of mild thermal treatments of foods requires knowledge concerning the influence of food microstructure and initial cell conditions on foodborne pathogens’ inactivation kinetics. The effect of food microstructure and initial cell conditions on thermal inactivation kinetics and sublethal injury (SI) of Listeria monocytogenes was investigated at 59, 64 and 69°C. Fish-based food model systems with different microstructures, possessing minimal compositional and physicochemical variations, were used. L. monocytogenes growth morphology had no significant influence on thermal inactivation kinetics. A gelled matrix resulted in a lower specific inactivation rate kmax and a higher residual cell population Nres, while the presence of fat droplets resulted in a higherkmaxand did not influenceNres. SI was higher in viscous than in gelled systems and more prominent for cells that were grown inside the matrix. Hence, predictive thermal inactivation models could benefit from the inclusion of factors related to the nature of the food matrix and fat properties. Starting inactivation from cells that were grown inside the matrix, resulted in lower (i.e., fail-safe)kmaxvalues and more uncertainty onNres as compared to starting from cells grown at optimal conditions.

Modified state diagrams of cellular and noncellular food model systems: Experimental data and mathematical modeling

The state diagram is an interesting approach to assess the stability of food products. In addition, the cellular structure could also have an impact on the behavior of food products during processing and storage. In this study, potato and carrot (cellular structure) and two gel food systems made from water–agar–maltodextrin (noncellular structure) were used to obtain experimental data of aw and Tg as a function of water content during drying. The Guggenheim–Anderson-de Boer (GAB), Flory–Huggins, Gordon–Taylor, and Khalloufi–Ratti models were assessed by comparing them to the experimental data. The results obtained showed that these mathematical expressions can be used to capture the experimental data profiles with acceptable accuracy. Both GAB and Khalloufi–Ratti models were used as tools to build the modified state diagrams of the four products investigated in this study. As the number of the samples studied was limited, it was not possible to establish whether cellular structures have a larger impact on Tg than other parameter such as the chemical composition of the products.

Enhanced bacterial inactivation in apple juice by synergistic interactions between phenolic acids and mild food processing technologies

This study demonstrated an innovative processing approach based on synergistic antimicrobial activity of two phenolic acids with mild thermal and non-thermal processing technologies. The two selected model phenolic acids were gallic acid (GA; 10 mM) and ferulic acid (FA; 1 mM). The processing technologies evaluated for processing of a model clarified apple juice were UV-A light, mild heat (55 °C) and moderate pressure (250 MPa), with processing times ranging from 1 to 30 min. The results demonstrated that combinations of selected phenolic acids and a mild physical processing were able to lower E. coli O157:H7 and Listeria innocua counts from 6-log CFU mL −1 to below the detection limit of 1-log CFU mL −1 . Bacterial inactivation was significantly enhanced by the combination of UV-A light processing and FA, where 10 min of treatment enhanced bacterial inactivation by 5-log as compared to light processing alone, which presented no bacterial inactivation. In contrast, the combination of GA and mild-temperature thermal processing (55 °C) or mild-levels of high-pressure processing (250 MPa), enhanced bacterial inactivation by 4-log as compared to the physical treatments alone, which presented only 1-log of inactivation. The influence of these synergistic combinations on bacterial membrane damage was assessed by selective plating technique under osmotic pressure. Furthermore, the total intracellular thiol content was also measured to assess for thiol oxidation. Overall, the results demonstrated enhanced bacterial inactivation based on synergistic interactions of selected phenolic acids with both mild-thermal and non-thermal technologies in a model food system and illustrate potential to create diversity of novel antimicrobial strategies for food processing. This study showed that the presence of naturally-based compounds can significantly reduce intensity levels of physical processing required to inactivate model gram-positive and gram-negative bacteria in apple juice. In this study two phenolic acids, ferulic acid and gallic acids were selected as these compounds are naturally present in many fruits and other food products including grains. Furthermore, the levels of these natural phenolic acids used in this study are comparable to the levels naturally present in some of the food materials. • Ferulic acid plus UV-A and gallic acid plus 55 °C or pressure showed synergistic inactivation in apple juice. • Ferulic acid at 1 mM resulted in 5-log CFU/mL bacterial inactivation with UV-A exposure. • Gallic acid at 10 mM resulted in 4-log CFU/mL bacterial inactivation with 55 °C or 250 MPa exposure. • Combination of gallic acid with heat or pressure increased intracellular thiol oxidation. • All observed synergistic combinations showed damage to bacterial membranes.

Spray-dried microcapsules of anthocyanin-rich extracts from Euterpe edulis M. as an alternative for maintaining color and bioactive compounds in dairy beverages.

Color is a sensory attribute that influences the acceptance of food and dyes are added into food products to provide them attractiveness. In this context, anthocyanins have merged as an alternative to synthetic dyes. This study aimed to develop food model systems of fermented or unfermented dairy beverages containing added microencapsulated anthocyanin-rich extracts from juçara palm fruit. The stabilities of both pigment and beverage throughout storage in opaque or transparent packaging have been evaluated. Acidity, pH and anthocyanin content in both beverages did not vary during 28days of storage, and the content of bioactive compounds did not decrease over time. A slight overall color difference that is probably invisible to naked eyes was detected between the beverages analyzed at days 0 and 28. The potential of applying microencapsulated natural pigments into dairy matrices is an effort to increase their nutritional and sensorial values.

Conditions Governing Food Protein Amyloid Fibril Formation. Part II: Milk and Legume Proteins.

Both intrinsic and extrinsic factors impact amyloid formation of food proteins. We here review the impact of various conditions and food constituents on amyloid fibrillation of milk and legume proteins. Much less is known about casein and legume protein amyloid-like fibril formation than about that of whey proteins such as β-lactoglobulin, α-lactalbumin, and bovine serum albumin. Proteins of both sources are often studied after heating under strong acidic (pH < 3) conditions. The latter induces changes in protein conformation and often peptide hydrolysis. At higher pH values, alcohols, chaotropic and/or reducing agents induce the conformational changes required to enhance fibrillation. Different types of food proteins can impact each other's fibrillation. Also, the presence of other food constituents can enhance or reduce it. No general conclusions on the mechanisms or impact of different food constituents on food proteins can be made. Optimal conditions for AF formation, that is, heating for several days at low pH, are rare in food processing. However, this does not exclude the possibility of AF formation in food products. For example, slow cooking of hydrolyzed proteins may enhance it. Future research should focus on the prevalence of AFs in complex food systems or model systems relevant for food processing.