Microencapsulated food-grade antioxidant applied as a preservative of peanut seed quality in microcosm- and pilot-scale trials

BACKGROUND

In Argentina, peanuts are stored for 3-6 months. It is important to avoid proliferation of fungi and insect pests during this period. In this study, the potential of butylated hydroxyanisole (BHA) microcapsules to conserve peanut kernels was evaluated in microcosms and on a pilot scale.

RESULTS

In microcosm assays, microcapsules containing BHA at a dose of 1802 µg g^-1 reduced 37% of total fungal count. Higher reductions (77-100%) were obtained with a combined treatment with BHA formulation (1802 µg g^-1 ) plus fungicide (methyl thiophanate 0.0100 g L^-1  and metalaxyl 0.0133 g L^-1 ). However, germination levels of peanut seeds treated with the BHA formulation were less than 6% throughout the incubation time. In pilot-scale trials, the storage conditions allowed the control of fungal development and insect proliferation. Quantifiable levels of BHA were also detected throughout the entire storage period. The combined treatment significantly reduced fungal contamination at 2 months of storage (C1-2015: 37.41%; C1-2016: 28.48%; C2-2016: 45.02%). Seed germination of unshelled stored peanuts was not affected by the formulation.

CONCLUSION

The application of the BHA formulation during storage combined with pre-seeding treatment could be an appropriate strategy to maintain the quality of the peanut kernels destined for seed. © 2018 Society of Chemical Industry.

Plant antimicrobial polyphenols as potential natural food preservatives

BACKGROUND

The growing demand for natural food preservatives in the last decade has promoted investigations on their application for preserving perishable foods. In this context, the present review is focused on discussing the prospective application of plant extracts containing phenolics or isolated plant phenolics as natural antimicrobials in foods. Plant essential oils are outside the scope of this review since utilization of their antimicrobial activity for food preservation has been extensively reviewed.

RESULTS

Although the exact antimicrobial mechanisms of action of phenolic compounds are not yet fully understood, it is commonly acknowledged that they have diverse sites of action at the cellular level. Antimicrobial phenolics can be added directly to the formulation of perishable food products or incorporated into food-contact materials to release them in the immediate zone of perishable foods. Edible coatings or active food packaging materials can thus be used as carriers of plant bioactive compounds.

CONCLUSION

These materials could be an interesting delivery system to improve the stability of phenolics in foods and to improve the shelf life of perishable foods. This review will thus provide an overview of current knowledge of the antimicrobial activity of phenolic-rich plant extracts and of the promises and limits of their exploitation for the preservation of perishable foods. © 2018 Society of Chemical Industry.

Effect of Antioxidant and Antimicrobial Coating based on Whey Protein Nanofibrils with TiO₂ Nanotubes on the Quality and Shelf Life of Chilled Meat

Whey protein nanofibrils (WPNFs) can be used in edible films and coatings (EFCs) because of its favorable functional properties, which rely on its well-ordered β-sheet structures, high hydrophobicity, homogeneous structure, and antioxidant activity. In the present study, WPNF-based edible coatings with glycerol (Gly) as plastic and titanium dioxide nanotubes (TNTs) as antimicrobial agents were studied. TNTs not only showed greater antibacterial activity than titanium dioxide nanoparticles (TNPs), but also increased interactions with WPNFs. The WPNF/TNT film had a smooth and continuous surface and was homogeneous with good mechanical properties. WPNF/TNT edible coatings (ECs) can help improve lipid peroxidation and antioxidant activity, limit microbial growth, reduce weight loss, and extend the shelf life of chilled beef. Given that the WPNF/TNT film components are low cost and show high antioxidant and antimicrobial activity, these optimized films have potential applications for various food products, including raw and chilled meat.

Development of propolis nanoemulsion with antioxidant and antimicrobial activity for use as a potential natural preservative

Propolis has demonstrated potential use as food preservative but it presents strong and unpleasant flavor that alters the sensory characteristics foods. A nanoemulsion was proposed to carry the Brazilian propolis extracts for use as natural food preservative. Antimicrobial and antioxidant activities and chemical constituents of the extracts were investigated. The latter were made by sequential extraction using different solvents (hexane, ethyl acetate and ethanol). Antimicrobial activity was evaluated by agar diffusion and microdilution methods and antioxidant activity by DPPH and ABTS assays. Extracts showed antibacterial and antioxidant activity, highlighting the ethanolic which contained artepillin-C, kaempferide, drupanin and p-coumaric acid as main compounds by LC-MS analysis. The nanoemulsion developed by phase inversion method was characterized and stable under thermal-stress and centrifugation conditions. Biological properties evaluated were effectively maintained by the formulation. It was concluded that the nanoemulsion can be used as a food preservative, preventing degradation and masking the propolis off-flavor.

Shelf life study of healthy pork liver pâté with added seaweed extracts from Ascophyllum nodosum, Fucus vesiculosus and Bifurcaria bifurcata

The effect of the addition of seaweed extracts from three brown algae species [Ascophyllum nodosum (AN), Fucus vesiculosus (FV) and Bifurcaria bifurcata (BB)], which are a great source of natural antioxidants, on the oxidative stability of refrigerated low-fat pork liver pâtés was studied. In the studied pâtés, half of pork fat was replaced with a mixture consisting of canola and high-oleic sunflower oil (75:25, v/v), thus improving their fatty acid profile in terms of polyunsaturated fatty acids (PUFA). In order to avoid the oxidation of PUFA in the new samples, seaweed extracts (500 ppm) were added. In addition, some samples were formulated with a synthetic antioxidant (BHT at 50 ppm) (BHT) and a control batch (CON) (without antioxidant) was also prepared, for comparison purposes. Thus, in total, five batches of liver pâté were prepared: CON, BHT, AN, FV and BB. Pâté samples were analyzed at 0, 45, 90, 135 and 180 days of refrigerated storage at 4 °C. The addition of seaweed extracts did not modify significantly (P > 0.05) the chemical composition or microbial characteristics of healthy pork liver pâté, except for the protein content, which resulted in a significant increase (≈2-3%) in the batches manufactured with addition of seaweed extracts compared to control samples. At the end of storage (180 days), L* values were significantly lower in the FV and BB batches than in the other batches. Moreover, the a* and b* values were also significantly lower in CON batches than in the samples with antioxidants added. Differences in oxidative parameters (conjugated dienes, TBARs and carbonyls) among batches were observed at the end of the storage time, showing samples with seaweed extracts a similar degree of protection against oxidation compared to BHT formulated samples. A decline of the volatile compounds was noted in all the batches during storage. The total volatile compounds at the end of the storage were significantly lower in BTH, AN, or BB batches than in control batches.

Effect of SO2 on sugars, indicators of Maillard reaction, and browning in dried apricots during storage

BACKGROUND

The effect of sulfur dioxide (SO₂ ) concentration was determined on sugars and indicators in the Maillard reaction (MR), and on browning, in sulfured, dried apricots (SDAs) during storage at 4, 20 and 30 °C for 379 days.

RESULTS

As SO₂ concentration increased, the content of reducing sugars involved in the MR also increased. The preventive effect of SO₂ on the MR could not result from the binding of SO₂ to reducing sugars. Before storage, furosine was detected in the non-SDAs but 5-hydroxymethylfurfural (HMF) was not detected. Even the lowest SO₂ concentration (451 mg kg^-1 ) was sufficient to prevent the formation of furosine and HMF during drying of apricots.

CONCLUSION

Formation of furosine and HMF in all samples during storage at 20 and 30 °C for 379 days indicated that SO₂ could not prevent the first and intermediate stages of MR in SDAs during storage. Thus, the main prevention effect of SO₂ on browning in SDAs occurred during drying, not storage. © 2018 Society of Chemical Industry.

Chitosan nanoparticles-loaded Citrus aurantium essential oil: a novel delivery system for preserving the postharvest quality of Agaricus bisporus

BACKGROUND

One of the main problems in the button mushroom industry is the rapid deterioration of fruit bodies after harvest. Today, nanotechnology has become a more reliable technique to improve the quality of products in food packaging. In the present study, the effectiveness of chitosan nanoparticles containing Citrus aurantium essential oil on postharvest quality of white button mushroom was examined and compared to essential oil fumigation and control treatments.

RESULTS

Based on high-resolution transmission electron microscopy and dynamic light scattering, nanoparticles exhibited a spherical shape of 20-60 nm diameter. The results revealed that the application of chitosan nanoparticles loaded with C. aurantium oil significantly decelerated the rate of color change, weight loss and firmness compared to fumigation with essential oil and control treatments. Treatment of fruit bodies with chitosan nanoparticles loaded with C. aurantium oil promoted the accumulation of phenolic compounds and ascorbic acid, and resulted in increases in catalase and superoxide dismutase and a decrease in polyphenol oxidase activities, as the highest antioxidant capacity was observed after 15 days of cold storage.

CONCLUSION

This present research demonstrates that gradual release of C. aurantium essential oil from chitosan nanoparticles could be an effective and practical method for extending the shelf life of white button mushroom up to 15 days without significant decrease in antioxidant capacity. © 2018 Society of Chemical Industry.

A novel superchilling storage - ice glazing (SS-IG) approach using biopolymer-based composite hydrogel to delay microbiological spoilage and organic oxidation of preserved tilapia

BACKGROUND

Most aquatic products are highly susceptible to deterioration and microbial spoilage during storage. Cold storage is a frequently used method to preserve them. However, products preserved by traditional frozen method are prone to suffer damage. This can significantly impair the quality of the products. To solve the problem, this work established a novel superchilling storage-ice glazing (SS-IG) approach using chitosan-catechin composite material. It can maximize the postmortem quality of preserved products during storage, avoiding damage.

RESULTS

During storage at -1.5 ± 0.2 °C for 25 days, the SS-IG approach using 5 g L^-1 chitosan and 1∼3 g L^-1 catechin as IG layers can effectively enhance the postmortem quality of preserved tilapia fillets. The sensory qualities of these fillets were effectively maintained. The microbial counts in these fillets were strongly suppressed. Oxidative rancidity in these fillets was observably inhibited. Less biogenic amine was produced in these fillets.

CONCLUSION

The results indicated that the SS-IG with chitosan-catechin composite-ice glazing layers can be effective in maintaining the postmortem quality of tilapia fillets. This will have a wide potential application. © 2018 Society of Chemical Industry.

Biodegradation of four selected parabens with aerobic activated sludge and their transesterification product

Parabens are preservatives widely used in foodstuffs, cosmetics and pharmaceuticals, which have led to elevated paraben concentrations in wastewater and receiving waters. Laboratory-scale batch experiments were conducted to investigate the adsorption and degradation of parabens in an aerobic activated sludge system. Results show that biodegradation plays a key role in removing parabens from the aerobic system of wastewater treatment plants, while adsorption on the sludge is not significant. The effects of parent paraben concentration, concentration of mixed liquor suspended solids (MLSS), initial pH and temperature on degradation were investigated using kinetic models. The data shows that the degradation of parabens could be described by the first-order kinetic model with the rate constant ranging from 0.10 to 0.88 h^-1 at 25 °C and pH 7.0. Paraben degradation can be enhanced by increasing the MLSS concentration and temperature, or by decreasing the parent paraben concentration. Furthermore, the pH of the incubation system should be lower than 8.0. The half-lives of the parabens were estimated to range between 0.79 and 6.9 h, with methylparaben exhibiting the slowest degradation rate. During degradation in the present system, transesterification occurred, with methylparaben being the major transformation product in the incubation systems of ethylparaben, propylparaben and butylparaben. These results were confirmed by mass spectrometry and aliphatic alcohol additive experiments. This is the first discovery of paraben transesterification in an activated sludge system, and it is associated with trace methanol in the system.

Natural curing agents as nitrite alternatives and their effects on the physicochemical, microbiological properties and sensory evaluation of sausages during storage

This study investigated the effects of different curing agents on the physicochemical properties, microbiological properties and sensory evaluation of sausages formulated with and without nitrite over 4 weeks of cold storage. Seven batches were prepared: control, sodium nitrite 0.01%; celery powder 0.8% (T1); fruit extract powder 0.6% (T2); purple sweet potato powder 0.45% (T3); fruit and vegetable extract powders 0.5% (T4); gardenia red 0.04% (T5); paprika and blueberry powder 0.07% (T6). T1 produced significantly lighter, redder and yellower sausages compared to control and had a higher color intensity (C*) and hue (h). The residual nitrite ion concentration was the highest in the control and declined most rapidly in control, T1, and T2 during storage. The pH, thiobarbituric acid reactive substances (TBARS), volatile basic nitrogen (VBN) content, and total microbe counts were the same for T1 and the control. T1 received comparable sensory attributes as the control. These results suggest that celery powder effectively protects sausages from quality deterioration during storage.

Effect of ultrasound and chemical treatment on total phenol, flavonoids and antioxidant properties on carrot-grape juice blend during storage

Ultrasonics is one of the developing technologies which is being studied extensively on different food commodities. Our aim was to study the effect of sonication and chemical (Potassium metabisulfite, K₂S₂O₅,) preservation method on grape-carrot juice blend. Sonication/ultrasound treatments (20 kHz frequency, 70% amplitude level (525 W power), and pulse duration 5 s on and 5 s off, 5 min at 15 °C) of all the samples (250 mL) were performed by using an ultrasonic processor with 0.5 in. probe at 2 in. depth of the sample. Additionally, impact of sonication on 90 days of storage period at refrigerated temperature was also measured. It was observed that sonication had a positive effect on nutritional status of juice blend as it enhanced the total phenolic, flavonoid, reducing power and antioxidant properties of juice significantly (p < 0.05) with increase in sonication time. Sonication can be employed successfully for treatment of juice with better nutritional attributes from consumers' point of view.

Formulation and Stabilization of Concentrated Edible Oil-in-Water Emulsions Based on Electrostatic Complexes of a Food-Grade Cationic Surfactant (Ethyl Lauroyl Arginate) and Cellulose Nanocrystals

We report on high-internal-phase, oil-in-water Pickering emulsions that are stable against coalescence during storage. Viscous, edible oil (sunflower) was emulsified by combining naturally derived cellulose nanocrystals (CNCs) and a food-grade, biobased cationic surfactant obtained from lauric acid and L-arginine (ethyl lauroyl arginate, LAE). The interactions between CNC and LAE were elucidated by isothermal titration calorimetry (ITC) and supplementary techniques. LAE adsorption on CNC surfaces and its effect on nanoparticle electrostatic stabilization, aggregation state, and emulsifying ability was studied and related to the properties of resultant oil-in-water emulsions. Pickering systems with tunable droplet diameter and stability against oil coalescence during long-term storage were controllably achieved depending on LAE loading. The underlying stabilization mechanism was found to depend on the type of complex formed, the LAE structures adsorbed on the cellulose nanoparticles (as unimer or as adsorbed admicelles), the presence of free LAE in the aqueous phase, and the equivalent alkane number of the oil phase (sunflower and dodecane oils were compared). The results extend the potential of CNC in the formulation of high-quality and edible Pickering emulsions. The functional properties imparted by LAE, a highly effective molecule against food pathogens and spoilage organisms, open new opportunities in food, cosmetics, and pharmaceutical applications, where the presence of CNC plays a critical role in achieving synergistic effects with LAE.

Effect of thyme oil-alginate-based coating on quality and microbial safety of fresh-cut apples

BACKGROUND

Food preservation is critical for keeping fresh-cut products fresh, nutritious, safe, attractive and available for consumers. To improve the safety and quality of fresh-cut fruits, 15 essential oils (EOs) were screened to test the antimicrobial activity against Listeria monocytogenes (LM), Salmonella typhimurium (ST), Staphylococcus aureus (SA) and Escherichia coli O157:H7 (EC O157:H7). The effect of alginate-based edible coating (EC) incorporating different concentrations thyme oil on fresh-cut 'Red Fuji' apples was investigated.

RESULTS

Results showed that thyme oil, cinnamon oil and oregano oil were more effective in inhibiting the microbes than other EOs. The result showed that the combined usage of 0.5 µL mL^-1 thyme oil incorporated with alginate-based EC could significantly inhibit the microbial growth, respiration, weight loss, firmness and browning of fresh-cut 'Red Fuji' apples.

CONCLUSION

The edible coating and natural additives like thyme oil could be used to preserve the quality of fresh-cut fruits. It revealed that EC incorporated with 0.5 µL mL^-1 thyme oil can be a safe preservative for fresh-cut apples. © 2017 Society of Chemical Industry.

Valorization of underutilized North American pawpaw (Asimina triloba): investigation as a lipid oxidation inhibitor in turkey homogenate model system

BACKGROUND

The objective of this study was to characterize the ability of extracts from nine varieties of pawpaw pulp standardized to the phenolics level of 0.1% grape seed extract (GSE) on inhibition of the formation of thiobarbituric reactive substances (TBARS) in a turkey model system. The antioxidant activity of the extracts was also determined using four common assays.

RESULTS

Over the 240 min sampling time, the standardized pawpaw extracts from all nine varieties were as effective as GSE in inhibiting TBARS formation in turkey muscle homogenate compared to the untreated control. Extracts from all pawpaw varieties and GSE began to inhibit TBARS formation at 60 min of incubation, and by 240 min TBARS were reduced from 35 μmol malondialdehyde kg^-1 tissue in the homogenate to which no antioxidant was added to 4-18 μmol malondialdehyde kg^-1 tissue in the antioxidant-enriched extracts. There does not appear to be a clear relationship between inhibition of TBARS and any of the antioxidant capacity measurements (ORAC, DPPH inhibition, reducing potential as measured by FRAP assay, or pyrogallol red bleaching).

CONCLUSION

The results of this research indicate that there is potential to add value to pawpaw as a functional food source of natural antioxidants, particularly in meat products. © 2017 Society of Chemical Industry.

Effect of Presence and Concentration of Plasticizers, Vegetable Oils, and Surfactants on the Properties of Sodium-Alginate-Based Edible Coatings

Achieving high quality of a coated food product is mostly dependent on the characteristics of the food material to be coated, the properties of the components in the coating solution, and the obtained coating material. In the present study, usability and effectiveness of various components as well as their concentrations were assessed to produce an effective coating material. For this purpose, different concentrations of gelling agent (sodium alginate 0-3.5%, w/w), plasticizers (glycerol and sorbitol (0-20%, w/w), surfactants (tween 40, tween 80, span 60, span 80, lecithin (0-5%, w/w), and vegetable oils (sunflower oil, olive oil, rapeseed oil (0-5%, w/w) were used to prepare edible coating solutions. Formulations were built gradually, and characteristics of coatings were evaluated by analyzing surface tension values and its polar and dispersive components, emulsion droplet size, and optical appearance in microscopic scale. The results obtained showed that 1.25% sodium alginate, 2% glycerol, 0.2% sunflower oil, 1% span 80, and 0.2% tween 40 or tween 80 can be used in formulation to obtain an effective coating for hydrophobic food surfaces. Three formulations were designed, and their stability (emulsion droplet size, optical characteristics, and creaming index) and wettability tests on strawberry showed that they could be successfully used in coating applications.

Microcapsules biologically prepared using Perilla frutescens (L.) Britt. essential oil and their use for extension of fruit shelf life

BACKGROUND

Perilla essential oil (EO) possesses high antioxidant, antimicrobial and insecticidal activities, and has proven to be more reliable than chemically synthesized food preservatives. Nevertheless, EOs have disadvantages of facile photo-degradation and oxidation, which limit their use in agriculture and food industries. Microencapsulation technology that generates a polymeric coating surrounding EOs could overcome these disadvantages.

RESULTS

The EO concentration had a significant effect on encapsulation efficiency (EE) and loading capacity (LC). The best encapsulation conditions were obtained with 2% v/v EO, for which EE and LC were 57% and 36%, respectively. EO-loaded microspheres exhibited a crimped surface with phanic lumps by scanning electron microscopy. Thermal stability experiments revealed droplets that began to decompose sharply at 108 °C, with a 61% weight, loss, which was much lower than EOs of 98%. EO-loaded microcapsules demonstrated good antibacterial activity. Strawberry preservation studies showed that EO-loaded microcapsules could significantly inhibit strawberry decay, maintain the quality of strawberries and prolong shelf life.

CONCLUSION

Perilla EO-loaded microcapsules were successfully prepared by ionic gelation and were effective at inhibiting several bacterial strains. EO-alginate microcapsules could effectively delay the volatilization of EO. Perilla EO-loaded microcapsules therefore have potential for use as an antimicrobial and preservative agent in the food industry. © 2017 Society of Chemical Industry.

Inter- and intra-individual variation in urinary concentrations of parabens in male and female Japanese subjects

We evaluated the representativeness of concentrations of parabens in a spot urine sample for the assessment of long-term exposure levels. Urine sample was taken monthly from 10 male Japanese subjects (35.9 ± 6.8 years) and 12 female Japanese university students (21.1 ± 0.4 years) for 5 months and measured for methyl (MP), ethyl (EP), propyl (PP) and butyl (BP) parabens by liquid chromatography-tandem mass spectrometry. Median (min-max) specific-gravity-adjusted urinary concentrations of the male group (n = 10) were 39.7 (2.99-268), 1.69 (< 0.045-75.2), 0.569 (< 0.11-123) and 0.0264 (< 0.020-24.4) ng mL^-1 for MP, EP, PP and BP, respectively. Those of the female group (n = 12) were 283 (5.49-1687), 9.30 (0.290-487), 22.9 (< 0.11-307) and 3.76 (< 0.020-135) ng mL^-1, respectively, which were significantly higher than those of the male group. Intra-class correlation coefficients (ICCs) were calculated for the four parabens to find 0.56, 0.58, 0.39 and 0.28 for MP, EP, PP and BP, respectively, in the male group, and 0.40, 0.43, 0.41 and 0.37 for MP, EP, PP and BP, respectively, in the female group. The results suggested that four paraben concentrations in a spot urine sample moderately reflected long-term paraben exposure of Japanese subjects. Source of exposure to parabens is also discussed.

Effects of antioxidative substances from seaweed on quality of refined liver oil of leafscale gulper shark, Centrophorus squamosus during an accelerated stability study

Crude liver oil of leafscale gulper shark, Centrophorus squamosus was clarified by sequential degumming, decolorization and vacuum deodorization. The refined oil was added with ethyl acetate extract of seaweeds and various physiochemical parameters were evaluated in a time-reliant accelerated storage study. Significantly greater induction time was observed for the oil supplemented with Sargassum wightii and Sargassum ilicifolium (>4.5h) than other seaweed extracts and control oil (~1h). Among different seaweeds, the ethylacetate extracts of S. wightii maintained the oxidation indices of the refined oil below the marginal limits after the study period. No significant reduction in C20-22 long chain fatty acids (1.19%) in the refined oil added with S. wightii was apparent, and was comparable with the synthetic antioxidants (1.07-1.08%). Spectroscopic fingerprint analysis of marker compounds responsible to cause rancidity signified the efficacy of S. wightii to arrest the development of undesirable oxidation products in the refined oil during storage. The antioxidant compounds, 15-(but-19-enyl)-hexahydro-13,16-dimethyl-11-oxo-1H-isochromen-8-yl benzoate (1) and 10-(but-13-en-12-yl)-5-((furan-3-yl)propyl)-dihydrofuran-9(3H)-one (2) isolated from S. wightii appeared to play a major role to deter the oxidative degradation of refined oil thereby enhancing the storage stability.

An overview of natural antimicrobials role in food

The present paper aims to review the natural food preservatives with antimicrobial properties emphasizing their importance for the future of food manufacturing and consumers' health. The extraction procedures applied to natural antimicrobials will be considered, followed by the description of some natural preservatives' antimicrobial mechanism of action, including (i) membrane rupture with ATP-ase activity inhibition, (ii) leakage of essential biomolecules from the cell, (iii) disruption of the proton motive force and (iiii) enzyme inactivation. Moreover, a provenance-based classification of natural antimicrobials is discussed by considering the sources of origin for the major natural preservative categories: plants, animals, microbes and fungi. As well, the structure influence on the antimicrobial potential is considered. Natural preservatives could also constitute a viable alternative to address the critical problem of microbial resistance, and to hamper the negative side effects of some synthetic compounds, while meeting the requirements for food safety, and exerting no negative impact on nutritional and sensory attributes of foodstuffs.

Polyphenolic-protein-polysaccharide ternary conjugates from Cystoseira barbata Tunisian seaweed as potential biopreservatives: Chemical, antioxidant and antimicrobial properties

The present study investigated the antioxidant and antimicrobial activities of naturally occurring Cystoseira barbata seaweed glyco-conjugates (CBGs), with a view to developing safer food preservatives. CBGs were successfully isolated, then chemically and structurally characterized. CBGs contained a high amount of polysaccharides (49.76%) that consisted mainly of neutral sugars (47.67%) and uronic acids (2.09%). The carbohydrate fraction was sulfated (13.81%) and conjugated with proteins (9.86%) and phenolic compounds (4.98%). Infrared spectroscopy of CBGs showed interactions between polyphenols, proteins and polysaccharides, which were characterized by α-type glycosidic bond and sulfate groups in the axial position of sugar residues. Neutral sugars analysis of CBGs by GC-MS revealed that conjugated polysaccharides were mainly composed of galactose (34.02%), fucose (26.25%) and mannitol (21.25%) with few amounts of other sugars such as glucose (5.78%), rhamnose (4.9%), xylose (3.22%) and mannose (2.22%). Analysis of the amino acid composition of CBGs showed a high level of essential amino acids (40.36%), in which threonine was the most relevant (10.28%). LC-QTOF-MS analysis of the phenolic fraction of CBGs showed a variety of phenolic compounds including flavonoids, phlorotannins and anthraquinone glycosides. CBGs exhibited potent antioxidant activities including radical scavenging activity, chelating ability and reducing power, and displayed noticeable antibacterial and antifungal activities, which may open the way to the development of a natural biopreservation strategy based on algae.

Report: Potential of nano-emulsions as phytochemical delivery system for food preservation

Nature is a rich source of bioactive phytochemicals. These plant based compounds have rich scope as antioxidants, antimicrobial compounds and food preservatives and so for long time to be used in meat, fruits, vegetables and processed food items, either as added preservative or as coating material in various food applications, but the major limitation is their limited solubility in a food grade medium. Nano-emulsion is a best choice as a medium having vast area of application. The major advantage of nano-emulsion would be the solubility of a vast group of compounds, due to the presence of water and lipid phases. In this way, nano-emulsions can be proved to be the most suitable candidate as phytochemical delivery system for food preservation. In present article, the use of phytochemicals as potent food preservatives has been reviewed, in context of solubility of phytochemicals in nano-emulsion and applications of food grade nano-emulsions to food systems.

A novel controlled release ethanol emitter: preparation and effect on some postharvest quality parameters of Chinese bayberry during storage

BACKGROUND

Reducing spoilage and prolonging the shelf-life of food materials are both critically important in the food industry. Among the many available preservatives, ethanol has been widely used for the storage of fruits and vegetables. Although a few ethanol emitters are available in the form of antimicrobial packaging, these ethanol emitters demonstrate high volatility, uncontrolled release and other disadvantages, and so the practical applications are limited.

RESULTS

A novel ethanol gel with a controlled release rate was prepared by a gelatification reaction between ethanol and sodium stearate to overcome the disadvantage of conventional ethanol emitters. The hardness, adhesiveness and cohesiveness of developed ethanol gels increased, whereas the springiness decreased along with an increase in the sodium stearate concentration. The release rate of ethanol in the gels was controlled by the concentration of sodium stearate, in which a first-order release kinetic was observed. The release rate constant (k) of the gels with 12.5, 37.5, 62.5 g kg^-1 of sodium stearate was 0.58 ± 0.029, 0.49 ± 0.035 and 0.41 ± 0.021 h^-1 , respectively, at 25 °C. The application of the controlled release ethanol emitter with respect to the storage of Chinese bayberry fruit demonstrated its ability to reduce the decay rate, maintain firmness and inhibit increased malondialdehyde content at 4 °C.

CONCLUSION

In terms of practical applications, an appropriate sodium stearate content can be selected in accordance with the storage period, aiming to achieve precise storage goals. Therefore, the ethanol emitter has potential application prospects as an active packaging for Chinese bayberry fruit, as well as for other perishable products. © 2017 Society of Chemical Industry.

Stability of Sodium Chlorate Residues in Frozen Tomato and Cantaloupe Homogenates

The objective of this study was to determine the stability of sodium chlorate in frozen (-24 °C) tomato or cantaloupe homogenates for up to 17 weeks (119 days). Chlorate stability was assessed by ultraperformance liquid chromatography-mass spectrometry (UPLC-MS/MS) at two fortification levels (80 or 600 ng/g for tomato and 200 or 3000 ng/g for cantaloupe, n = 3 each) for each fruit after storage for 0, 1, 7, 14, 28, 56, or 119 d. Within matrix type, chlorate recovery was determined by fortifying duplicate blank homogenate samples on the day of analysis with the same concentrations used for the stability samples. Chlorate limits of quantitation for cantaloupe and tomato matrices were 30 and 60 ng/g, respectively. Sodium chlorate residues were stable (P > 0.05) in frozen tomato and cantaloupe homogenates during storage for 119 days at -24 °C.

Effect of postharvest methyl jasmonate treatment on fatty acid composition and phenolic acid content in olive fruits during storage

BACKGROUND

The nutritional effects of both table olives and olive oil are attributed not only to their fatty acids but also to antioxidant phenolics such as phenolic acids. Delays in oil processing usually result in undesirable oxidation and hydrolysis processes leading to formation of free fatty acids. These alterations create the need to process oil immediately after olive harvest. However, phenolic content decreases drastically during olive storage resulting in lower quality oil. In the present study we propose postharvest methyl jasmonate treatment as a mean to avoid changes in fatty acid composition and losses of phenolic acids during olive storage.

RESULTS

Contents of fatty acids and phenolic acids were estimated in methyl jasmonate treated olives throughout 30-day storage, as compared with those of untreated olives. Significant decreases of saturated fatty acids were observed in treated samples whereas increases of oleic, linoleic and linolenic acids were respectively measured (i.e. from 50.8% to 64.5%, from 7.2% to 9.1% and from 1.5% to 9.3%). Also, phenolic acid contents increased significantly in treated olives. Particularly, increases of gallic acid from 1.35 to 6.29 mg kg^-1 , chlorogenic acid from 9.18 to 16.21 mg kg^-1 , vanillic acid from 9.61 to 16.99 mg kg^-1 , caffeic acid from 5.12 to 12.55 mg kg^-1 , p-coumaric acid from 0.96 to 5.31 mg kg^-1 and ferulic acid from 4.05 to 10.43 mg kg^-1 were obtained.

CONCLUSION

Methyl jasmonate treatment is proposed as an alternative postharvest technique to traditional methods to guarantee olive oil quality when oil processing is delayed and olive fruits have to necessarily to be stored. © 2016 Society of Chemical Industry.

Improving the water solubility and antimicrobial activity of silymarin by nanoencapsulation

The aims of this study were to improve the water solubility and antimicrobial activity of milk thistle silymarin by nanoencapsulation and to assess the functions of silymarin nanoparticle-containing film as an antimicrobial food-packaging agent. Silymarin nanoparticles were prepared using water-soluble chitosan (WCS) and poly-γ-glutamic acid (γ-PGA). As the WCS and silymarin concentrations increased, particle size and polydispersity index (PDI) significantly increased. Nanoencapsulation significantly improved the water solubility of silymarin 7.7-fold. Antimicrobial activity of silymarin was effectively improved when silymarin was entrapped within the nanocapsule compared to when it was not entrapped. Films incorporating silymarin nanoparticles had better antimicrobial activity than films incorporating free silymarin. The results suggest that silymarin nanoparticles have applications in antimicrobial food additives and food packing.