A novel antifungal surface-coating application to limit postharvest decay on coated apples: Molecular, thermal and morphological properties of electrospun zein–nanofiber mats loaded with curcumin

Electrospinning zein with theaflavin: Production, characterization, and application in active packaging for cold-fresh pork

The interest and demand for active food packaging made from all natural materials have increased significantly, driven by the intent to minimize the ecological impact. Green electrospinning from biopolymers with antimicrobial compounds is considered an ideal candidate for constructing ultrathin, excellent performance, and effective antibacterial fibrous films (FFs). Here, a green electrospinning from zein (Z) ethanol-aqueous solution with varied theaflavin (TF) concentrations (0.6-4 %) was utilized as active packaging for cold-fresh pork. All the Z/TF composite fibrous films (ZTF-FFs) exhibited smooth and uniform surfaces, and their average fiber diameter increased from 484 nm to 705 nm with higher TF concentration. TF addition altered the secondary and crystalline structure of Z-FF, evidenced by Fourier-transform infrared spectroscopy and X-ray diffraction. At 1 % TF addition, ZTF1-FF displayed enhanced thermodynamic stability, with a decomposition residue of 13.88 % and a maximum mass loss rate temperature of 313.45 °C. ZTF1-FF also exhibited excellent hydrophobicity, superior mechanical properties, and significant antibacterial activity against S. aureus and S. paratyphi B. When used for active packaging of cold-fresh pork, ZTF1-FF significantly delayed the increases in total volatile basic nitrogen, total viable count, pH, weight loss, and thiobarbituric acid reactive substances of the pork. Overall, ZTF1-FF showed the most promising potential as an active food packaging material, particularly for preserving cold-fresh meat.

Electrospun zein nanofibers loaded with curcumin as a wound dressing: enhancing properties with PSS and PDADMAC layers

Development of wound dressings with enhanced therapeutic properties is of great interest in the modern healthcare. In this study, a zein-based nanofibrous wound dressing containing curcumin as a therapeutic agent was fabricated through electrospinning technique. In order to achieve desirable properties, such as antibacterial characteristics, reduced contact angle, and enhanced mechanical properties, the layer-by-layer technique was used for coating the surfaces of drug-loaded nanofibers by sequentially incorporating poly (sodium 4-styrene sulfonate) as a polyanion and poly (diallyldimethylammonium chloride) (PDADMAC) as a polycation. Various analyses, including scanning electron microscopy, Fourier transform infrared spectroscopy, drug release assessment., and mechanical tests were employed to assess the characteristics of the prepared wound dressings. Based on the results, coating with polyelectrolytes enhanced the Young's modulus and tensile strength of the electrospun mat from 1.34 MPa and 4.21 MPa to 1.88 MPa and 8.83 MPa, respectively. The coating also improved the controlled release of curcumin and antioxidant activity, while the outer layer, PDADMAC, exhibited antibacterial properties. The cell viability tests proved the appropriate biocompatibility of the prepared wound dressings. Moreover, our findings show that incorporation of the coating layers enhances cell migration and provides a favorable surface for cell attachment. According to the findings of this study, the fabricated nanofibrous wound dressing can be considered a promising and effective therapeutic intervention for wound management, facilitating the healing process.

Smart and UV-Resistant Edible Coating and Films Based on Alginate, Whey Protein, and Curcumin

In this work, smart edible coating and films with excellent UV barrier properties were prepared from alginate, whey protein isolate, and curcumin. The primary focus of this investigation centered on assessing the impact of whey protein and curcumin on the physical and functional properties of the alginate films. Whey protein reduced the film transparency while simultaneously enhancing the hydrophobicity and antioxidant properties of the alginate film. Curcumin imparted a yellow hue to the film, consequently decreasing the transparency of the film. It also substantially improved hydrophobicity, antioxidant activity, and UV-blocking efficiency within the films. Remarkably, curcumin demonstrated a significant reduction in the water vapor transmission rate of the film. For the preservation of apples, a higher concentration of curcumin was required, which effectively suppressed the respiration rate and moisture loss post-harvest, resulting in an extended shelf-life for the apples. As a result, the coated apples exhibited significantly reduced enzymatic browning and weight loss in comparison to their uncoated counterparts. Furthermore, these curcumin-containing films underwent a reversible color change from orange to red when exposed to ammonia vapor. This attribute highlights the potential of the developed coating and film as a smart, active food packaging solution, particularly for light-sensitive food products.

Emulsion electrospinning of zein nanofibers with carotenoid microemulsion: Optimization, characterization and fortification

In this study, carotenoid microemulsion was encapsulated in zein nanofibers via emulsion electrospinning. Optimization study was applied to determine optimum parameters by response surface methodology. The voltage, flow rate and distance as optimum conditions were determined as 23 kV, 1.7 mL/h and 12.75 cm, respectively. Lycopene, β-carotene, encapsulation efficiency, encapsulation yield and zeta potential of zein nanofibers in optimum conditions were estimated as 4.054 mg/kg, 0.649 mg/kg, 77.78%, 41.76% and -29.73 mV, respectively. The addition of microemulsion affected nanofibers diameter and morphologies. Diffusion coefficient of zein nanofibers decreased with addition of microemulsion under optimum conditions. The electrospinning improved thermal stability of microemulsion. The carotenoid microemulsion could be entrapped into the zein fibers according to ATR-FTIR spectrum. Model foods were fortificated with zein nanofibers. The addition of nanofibers changed color of the foods during the storage. Carotenoid compounds were more stable in nanofibers followed by olive oil, milk and water.

Biomaterials and Encapsulation Techniques for Probiotics: Current Status and Future Prospects in Biomedical Applications

Probiotics have garnered significant attention in recent years due to their potential advantages in diverse biomedical applications, such as acting as antimicrobial agents, aiding in tissue repair, and treating diseases. These live bacteria must exist in appropriate quantities and precise locations to exert beneficial effects. However, their viability and activity can be significantly impacted by the surrounding tissue, posing a challenge to maintain their stability in the target location for an extended duration. To counter this, researchers have formulated various strategies that enhance the activity and stability of probiotics by encapsulating them within biomaterials. This approach enables site-specific release, overcoming technical impediments encountered during the processing and application of probiotics. A range of materials can be utilized for encapsulating probiotics, and several methods can be employed for this encapsulation process. This article reviews the recent advancements in probiotics encapsulated within biomaterials, examining the materials, methods, and effects of encapsulation. It also provides an overview of the hurdles faced by currently available biomaterial-based probiotic capsules and suggests potential future research directions in this field. Despite the progress achieved to date, numerous challenges persist, such as the necessity for developing efficient, reproducible encapsulation methods that maintain the viability and activity of probiotics. Furthermore, there is a need to design more robust and targeted delivery vehicles.

Recent insights into Nanoemulsions: Their preparation, properties and applications

The ever-increasing demand for healthy diet by consumers has prompted the research adopting cutting-edge methods that can maintain the quality of fruits and vegetables without the use of preservatives. Emulsion based coating approach has been regarded as a viable way to extend the shelf life of fresh produce. New opportunities are being created in a number of industries, (medicines, cosmetics and food) because of new advancements in the developing field of nanoemulsions. Nanoemulsion based methods are efficient for encapsulating the active ingredients including antioxidants, lipids, vitamins and antimicrobial agents owing to the small droplet size, stability and improved biological activity. This review provides an overview of recent developments in preserving the quality and safety of fresh-cut fruits & vegetables with nanoemulsion as a carrier of functional compounds (antimicrobial agents, antibrowning/antioxidants and texture enhancers). In addition, material and methods used for fabrication of the nanoemulsion is also described in this review. In addition, material and methods used for fabrication, of the nanoemulsion is also present.

A review of curcumin in food preservation: Delivery system and photosensitization

As a natural polyphenol, curcumin has been used as an alternative to synthetic preservatives in food preservation. Different from previous reviews that mainly focus on the pH-responsive discoloration of curcumin to detect changes in food quality in real time, this paper focuses on the perspective of the delivery system and photosensitization of curcumin for food preservation. The delivery system is an effective means to overcome the challenges of curcumin like instability, hydrophobicity, and low bioavailability. Curcumin as a photosensitizer can effectively sterilize to preserve food. The practical fresh-keeping effects of the delivery system and photosensitization of curcumin on foods (fruits/vegetables, animal-derived food, and grain) were summarized comprehensively, including shelf-life extension, maintenance of physicochemical properties, nutritional quality, and sensory. Future research should focus on the development of novel curcumin-loaded materials used for food preservation, and most importantly, the biosafety and accumulation toxicity associated with these materials should be explored.

A review of potential antibacterial activities of nisin against Listeria monocytogenes: the combined use of nisin shows more advantages than single use

Listeria monocytogenes is a foodborne pathogen causing serious public health problems. Nisin is a natural antimicrobial agent produced by Lactococcus lactis and widely used in the food industry. However, the anti-L. monocytogenes efficiency of nisin might be decreased due to natural or acquired resistance of L. monocytogenes to nisin, or complexity of the food environment. The limitation of nisin as a bacteriostatic agent in food could be improved using a combination of methods. In this review, the physiochemical characteristics, species, bioengineered mutants, and antimicrobial mechanism of nisin are reviewed. Strategies of nisin combined with other antibacterial methods, including physical, chemical, and natural substances, and nanotechnology to enhance antibacterial effect are highlighted and discussed. Additionally, the antibacterial efficiency of nisin applied in real meat, dairy, and aquatic products is evaluated and analyzed. Among the various binding treatments, the combination with natural substances is more effective than the combination with physical and chemical methods. However, the combination of nisin and nanotechnology has more potential in terms of the impact on food quality.

A novel anthocyanin electrospun film by caffeic acid co-pigmentation for real-time fish freshness monitoring

In recent years, the use of intelligent and efficient food freshness indicators (FFIs) for monitoring food freshness has been studied widely. In this work, we employed polyacrylonitrile as polymer, blueberry anthocyanins as an indicator, and caffeic acid as a co-pigment and fabricated a novel colorimetric sensing film for real-time monitoring the freshness of fish. The total volatile basic nitrogen (TVB-N) level is one of the potential indicators to evaluate meat freshness. Visual observation confirmed that the polyacrylonitrile-anthocyanin-caffeic acid film changed from pink to light purple, and then to dark purple providing a good indication of spoilage, which correlated well with the TVB-N content and pH values in fish. It is because the volatile ammonia combined with water to form NH₃·H₂O, and then NH₃·H₂O is hydrolyzed to form OH^- and NH₄⁺. The change of the polyacrylonitrile-anthocyanin film was caused by OH^-. Compared with the polyacrylonitrile-anthocyanin film without caffeic acid, the addition of the caffeic acid film had enhanced significantly ammonia responsiveness with a total color difference value of 29.897. And it was also observed that caffeic acid obviously improved the storage stability of the film. This study provided a reference for detecting food freshness using co-pigmentation and electrospinning encapsulation technology in combination.

Production of Bacillus subtilis soil isolate as biocontrol agent under bioreactor conditions

This study aimed to investigate the biomass production of Bacillus subtilis in flask and bioreactor conditions. It is necessary to carry the culture from the shake flask to the pH, air, temperature and stirring controlled bioreactor in order to reduce the working time and increase the production efficiency and product quality. In this study, Bacillus was isolated from soil and grown under flask and bioreactor conditions as biocontrol agent against Botrytis cinerea and Fusarium oxysporum. In this process, a pH value of 7.5, 100% O₂ saturation, 30% dissolved O₂, at the temperature of 37 °C, total flow of 0.1 Lmin^-1 and mixing speed of 150 min^-1 were preferred for optimal concerning high production yield of B. subtilis in bioreactor. To test whether B. subtilis has antifungal activity on the growth of B. cinerea and F. oxysporum, a dual culture assay in a PDA medium was carried out. Ultimately, high biomass production in a short incubation period by reaching 2.2 µg/mL after 9 h in the bioreactor. It was observed that the bacteria produced in the bioreactor cultivation grew stronger and showed high antifungal activity which resulted 33.33% inhibition percentage against B. cinerea. It was concluded that B. subtilis can be used as a green-fungicide against B. cinerea and F. oxysporum, and bacterial metabolites from B. subtilis could pave the way for the development of next generation green/biopesticides.

Determination of the Antifungal, Antibacterial Activity and Volatile Compound Composition of Citrus bergamia Peel Essential Oil

Safe and health-beneficial citrus oils can be employed as natural preservatives, flavorings, antioxidants, and as antibacterial and antifungal agents in a wide variety of food products. In this research, using GC−MS methodology, the major volatile composition of Citrus bergamia EO, obtained by hydro-distillation, was determined to consist of limonen (17.06%), linalool (46.34%) and linalyl acetate (17.69%). The molecular fingerprint was obtained using FTIR spectroscopy. The antibacterial effect of C. bergamia EO at different concentrations (0.5, 1, 2.5 and 5 µg/mL) was tested against different pathogen species (Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes), based on disc diffusion assay. The in vitro antifungal activity of C. bergamia EO oil against Aspergillus niger and Penicillium expansum was evaluated using agar disc diffusion assay. Clear inhibition zones were formed by C. bergamia EO against selected species of pathogens. Almost all of the concentrations were revealed to have antifungal activity against selected fungal pathogens. The highest inhibition rate of A. niger at 6 incubation days was 67.25 ± 0.35 mm with a 20 µL dose, while the growth in the control was 90.00 ± 0.00 mm. In addition, the highest inhibition rate of P. expansum was 26.16 ± 0.76 mm with a 20 µL dose, while the growth was 45.50 ± 2.12 mm in the control fungus. A higher antifungal effect of C. bergamia EO against P. expansum was obtained. It was observed that the growth of fungi was weakened with increasing concentrations (5, 10, 15 and 20 µL dose) of C. bergamia EO. Statistically significant (p < 0.05) results were obtained for the antibacterial and antifungal effects of C. bergamia EO. The findings from the research may shed light on the further use of C. bergamia EO obtained from peels in innovative food engineering applications in order to maintain food quality, food safety, and food sustainability.

Nanofiber could deliver lactic acid bacteria to the intestine of ruminant in vitro experiment

This study investigates the use of nanofiber microcapsules produced by electrostatic spinning as a carrier for the delivery of lactic acid bacteria (LAB) to the intestine of ruminants. We hypothesized that the LAB encapsulated into nanofiber microcapsules can be delivered to a ruminant's intestinal tract with little effect on the rumen fermentation and related bacteria. The in vitro experiment included three treatments: control group; 0.01g Lactobacillus acidophilus NCFM (L. acidophilus NCFM) encapsulated in nanofiber microcapsules by electrostatic spinning group (ELAN, 2.0 × 10¹¹  CFU/g); and 0.01g L. acidophilus NCFM powder group (LANP, 2.0 × 10¹¹  CFU/g), each incubated with 30 ml of buffer rumen fluid for 48h to determine the effect on rumen fermentation, then the abundance of L. acidophilus NCFM in the intestine was estimated using the modified in vitro three-step procedure. Treatment responses were statistically analysed using one-way ANOVA. The results showed that compared to the control, the ELAN group had a significant increase in pH (p < 0.05), while the LANP group had a non-significant decrease in pH (p > 0.05). LANP and ELAN groups had no significant influence on total volatile fatty acid and individual volatile fatty acids (p > 0.05), apart from isobutyric acid of both groups, which reduced (p < 0.05). ELAN group had a decreasing trend of gas production and dry matter digestion, while the LANP group increased them significantly (p < 0.05). During the 16h and 48h rumen incubation, compared with control, there was no significant change in all bacteria in the ELAN group (p > 0.05), while the LANP group increased the relative abundance levels of S. bovis, S. ruminantium, M. elsdenii, F. succinogenes, B. fibrisolvens, Lactobacillus, L. acidophilus NCFM (p < 0.05). In the intestinal part, compared with control, the relative abundance of L. acidophilus NCFM in the ELAN group increased significantly (p < 0.05), while the result was not observed in the LANP group. We concluded based on our findings that L. acidophilus NCFM could be protected by nanofiber microcapsules and delivered to the intestinal site with little influence on the rumen fermentation and bacterial community, suggesting nanofiber microcapsules prepared by electrospinning technology could be used as a carrier for rumen-protected study.

Hierarchically Porous Films Architectured by Self-Assembly of Prolamins at the Air-Liquid Interface

Artificial recapitulation of hierarchically porous films gained great interest due to their versatile functionalities and applications. However, the development of novel eco-friendly and nontoxic biopolymer-based porous films is still limited by the time-consuming fabrication processes and toxic organic reagents involved. Here, we reported a novel approach to rapidly (within 5 s) fabricate biopolymer-based hierarchically porous films via inducing the laterally occurring interfacial self-assembly of prolamins at the air-liquid interface during an antisolvent dripping procedure. The as-prepared films exhibited a hierarchically porous microstructure (with sizes of about 500 nm to 5 μm) with location-graded and Janus features. The formation mechanism involved the solvent gradient controlled self-assembly of prolamin into an anisotropic defect structure in longitudinal and lateral directions. Accordingly, the macroscopic morphologies together with the porosity and pore size could be precisely tuned by solvents and operating parameters in a convenient way. Furthermore, alcohol-soluble but water-insoluble bioactive compounds could be incorporated simultaneously via a one-step loading procedure, which endowed films with large loading efficiency and sustained release features suitable for controlled release applications. The effect of the curcumin-loaded porous film on skin wound healing, as one of the potential applications of this novel material, was then investigated in vivo in a full-thickness wound model, wherein satisfying wound healing effects were achieved through multitarget and multipathway mechanisms. This pioneering work offers a novel strategy for the rapid architecture of biopolymer-based hierarchically porous film with versatile application potentials.

Zein-based nano-delivery systems for encapsulation and protection of hydrophobic bioactives: A review

Zein is a kind of excellent carrier materials to construct nano-sized delivery systems for hydrophobic bioactives, owing to its unique interfacial behavior, such as self-assembly and packing into nanoparticles. In this article, the chemical basis and preparation methods of zein nanoparticles are firstly reviewed, including chemical crosslinking, emulsification/solvent evaporation, antisolvent, pH-driven method, etc., as well as the pros and cons of different preparation methods. Various strategies to improve their physicochemical properties are then summarized. Lastly, the encapsulation and protection effects of zein-based nano-sized delivery systems (e.g., nanoparticles, nanofibers, nanomicelles and nanogels) are discussed, using curcumin as a model bioactive ingredient. This review will provide guidance for the in-depth development of hydrophobic bioactives formulations and improve the application value of zein in the food industry.

Biodegradable active packaging: Components, preparation, and applications in the preservation of postharvest perishable fruits and vegetables

The consumption of fresh fruits and vegetables is restricted by the susceptibility of fresh produce to deterioration caused by postharvest physiological and metabolic activities. Developing efficient preservation strategies is thus among the most important scientific issues to be urgently addressed in the field of food science. The incorporation of active agents into a polymer matrix to prepare biodegradable active packaging is being increasingly explored to mitigate the postharvest spoilage of fruits and vegetables during storage. This paper reviews the composition of biodegradable polymers and the methods used to prepare biodegradable active packaging. In addition, the interactions between bioactive ingredients and biodegradable polymers that can lead to plasticizing or cross-linking effects are summarized. Furthermore, the applications of biodegradable active (i.e., antibacterial, antioxidant, ethylene removing, barrier, and modified atmosphere) packaging in the preservation of fruits and vegetables are illustrated. These films may increase sensory acceptability, improve quality, and prolong the shelf life of postharvest products. Finally, the challenges and trends of biodegradable active packaging in the preservation of fruits and vegetables are discussed. This review aims to provide new ideas and insights for developing novel biodegradable active packaging materials and their practical application in the preservation of postharvest fruits and vegetables.

Surface Functionalization of Bamboo with Silver-Reduced Graphene Oxide Nanosheets to Improve Hydrophobicity and Mold Resistance

A natural polyphenolic compound was used to assemble nanocomposites. Owing to its stable bioactive properties, bamboo has earned significant attention in material science. Its high nutrient content and hydrophilicity makes bamboo more vulnerable to mold attacks and shortened shelf lives. To produce efficient, multipurpose, long-life bamboo products, a novel technique involving an immersion dry hydrothermal process was applied to impregnate the bamboo with polyphenol-assisted silver-reduced graphene oxide nanosheets. Curcumin (Cur), a natural polyphenol found in the rhizome of Curcuma longa, was used in the preparation of curcumin-enhanced silver-reduced graphene oxide nanosheets (Cur-AgrGONSs). The nanocomposites and nanocomposite-impregnated bamboo materials were examined by field emission scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. At the same time, a phytopathogen was isolated from infected bamboo products and identified by internal transcribed spacer (ITS) sequences. The nanocomposites effectively inhibited the growth of the isolated fungus. The mold resistance and moisture content of both the treated and untreated bamboo timbers were also examined to determine the efficiency of the prepared nanocomposite. The antifungal activity and hydrophobicity of the bamboo materials were significantly enhanced after the incorporation of curcumin-enriched silver-loaded reduced graphene oxide nanosheets (B@Cur-AgrGONSs). This research outcome confirms that the nanocomposite is a well-organized antimicrobial material for different advanced domains.

Immobilization of phlorotannins on nanochitin: A novel biopreservative for refrigerated sea bass (Lateolabrax japonicus) fillets

A novel biopreservative was developed by immobilizing phlorotannins into nanochitin (NCh). NCh were selected as a host complex to immobilized phlorotannins and the structural properties and antioxidant activity of the NCh-phlorotannins nanocomplex was investigated. The NCh-phlorotannins showed high antioxidant activity, as evidenced by free radical scavenging activity test. Moreover, the effects of NCh-phlorotannins on physical [color, water holding capacity (WHC), and texture], chemical [thiobarbituric acid (TBA) values, total volatile base nitrogen (TVB-N), and pH], microbiological [total viable count], changes of refrigerated sea bass (Lateolabrax japonicus) fillets were also evaluated. Sea bass fillets add with 1.5 g/kg NCh-phlorotannins had lower bacterial growth, pH, TVB-N and TBA as well as better characteristics of texture, color, and WHC than those of the control group during refrigerated storage. The efficiency of NCh-phlorotannins treatment was also better than that of phlorotannins or NCh treatment alone. Therefore, NCh-phlorotannins may be a potential biopreservative to extend the shelf-life of sea bass fillets quality during refrigerated storage.

Plant protein-based fibers: Fabrication, characterization, and potential food applications

Proteins from plants have been considered as safer, healthier, and more sustainable resources than their animal counterparts. However, incomplete amino acid composition and relatively poor functionality limit their applications in foods. Structuring plant proteins to fibrous architectures enhances their physicochemical properties, which can favor various food applications. This review primarily focuses on fabrication of fibers from plant proteins via self-assembly, electrospinning, solution blow spinning, wet spinning, and high-temperature shear, as well as on several applications where such fibrous proteins assemble in quality foods. The changes of protein structure and protein-protein interactions during fiber production are discussed in detail, along with the effects of fabrication conditions and protein sources on the morphology and function of the fibers. Self-assembly requires proteolysis and subsequent peptide aggregation under specific conditions, which can be influenced by pH, salt and protein type. The spinning strategy is more scalable and produces uniformed fibers with larger length scales suitable for encapsulation, food packaging and sensor substrates. Significant progress has been made on high-temperature shear (including extrusion)-induced fibers responsible for desirable texture in meat analogues. Structuring plant proteins adds values for broadened food applications, but it remains challenging to keep processes cost-effective and environmentally friendly using food grade solvents.

The application of polyphenols in food preservation

Polyphenols are a kind of complex secondary metabolites in nature, widely exist in the flowers, bark, roots, stems, leaves, and fruits of plants. Numerous studies have shown that plant-derived polyphenols have a variety of bioactivities due to their unique chemical structure, such as antioxidant, antimicrobial, and prevention of chronic diseases, cardiovascular disease, cancer, osteoporosis, and neurodegeneration. With the gradual rise of natural product development, plant polyphenols have gradually become one of the research hotspots in the field of food science due to their wide distribution in the plants, and the diversity of physiological functions. Owing to the extraordinary antioxidant and antibacterial activity of polyphenols, plant-derived polyphenols offer an alternative to chemical additives used in the food industry, such as oil, seafood, meat, beverages, and food package materials. Based on this, this chapter provides an overview of the potential antioxidant and antibacterial mechanisms of plant polyphenols and their application in food preservation, it would be providing a reference for the future development of polyphenols in the food industry.

Investigation of the antifungal effects of algal extracts on apple-infecting fungi

It is known that cell extracts of various algae have antifungal activity against microorganisms in vitro. Antifungal activities of Ulva lactuca, Chlorella vulgaris, Chlorella minutissima, and Chlorella protothecoides were investigated against: Aspergillus niger, Alternaria alternata, and Penicillium expansum fungi to present their fungicide potentials. Aspergillus niger, Alternaria sp., and Penicillium expansum are typical soft-rotting fungi and cause important loss of apple fruit in the storage. In vitro antifungal activity was evaluated by agar disc diffusion assay against pathogenic apple rot fungi. As a result, almost all of the extracts obtained from algae species were revealed to have antifungal activity against selected fungal pathogens. Free radical-scavenging activity of the extracts was determined with 1,1-diphenyl-2 picryl hydrazyl (DPPH) free radical-scavenging method. Extract of C. protothecoides was determined to have a stronger antioxidant activity than other algae extracts. This study reveals that the potential of algae should be investigated for the production of natural fungicide for pharmaceutical and food industries.

Characterization of Hazelnut Milk Powders: A Comparison of Spray-Drying and Freeze-Drying

Production of hazelnut milk powder (HMP) was investigated using maltodextrin (MD) as supporting material. Spray-drying and freeze-drying techniques were used to obtain the powder material. MD was added at concentrations of 5%, 10% and 15% (w/w) prior to drying. The powder properties were evaluated by determining flowing properties (Hausner ratio and angle of repose), thermal behaviour using DSC, molecular properties using FTIR, solubility and zeta potential. Hausner Ratio for both spray dried (SDHMP) and freze-dried (FDHMP) samples varied from 1.30 to 1.64 corresponding to very poor flow. The FDHM powder samples exhibited slightly lower Hausner Ratio values than SDHM powders. FTIR spectras showed that both SDHM and FDHM exhibited similar absorbance characteristics with slight differences. Lower endothermic transition temperatures were recorded from FDHMP when compared to SDHMP. The solubility in water for both powder samples ranged from 20 to 65 % depending on the drying method and MD content. Based on the residual moisture content, water activity, solubility and flowability, spray drying process was found to produce better quality powders compared to freeze drying process.