For the first time, alginate polymer has been applied to prevent dyes from leaching out of colorimetric oxygen indicator films, which enable people to notice the presence of oxygen in the package in an economic and simple manner. The dye-based oxygen indicator film suffers from dye leaching upon contact with water. In this work, UV-activated visual oxygen indicator films were fabricated using thionine, glycerol, P25 TiO2, and zein as a redox dye, a sacrificial electron donor, UV-absorbing semiconducting photocatalyst, and an encapsulation polymer, respectively. When this zein-coated film was immersed in water for 24h, the dye leakage was as high as 80.80±0.45%. However, introduction of alginate (1.25%) as the coating polymer considerably diminished the dye leaching to only 5.80±0.06%. This is because the ion-binding ability of alginate could prevent the cation dye from leaching into water. This novel water-resistant UV-activated oxygen indicator was also successfully photo-bleached and regained colour fast in the presence of oxygen.

Nowadays people demand for healthy, convenient, and wholesome foods. Double emulsions have attracted widespread attention in the food industry owing to their capability of encapsulating the compounds, fabricating polymersomes, and acting as fat replacers or sweetness enhancers in different foods. In this review, properties and their importance in the fabrication of double emulsions along with their advantages and disadvantages are discussed. In the lateral part of the manuscript, the instability mechanism and the effect of different variables on the stability of the double emulsions are reviewed. Finally, this review provides a glimpse of the recent food application of W/O/W double emulsions. Double emulsions have a better profile on the encapsulation of nutrients along with maintenance of the organoleptic quality of the food. The conventional emulsification techniques result in low encapsulation efficiency and poor monodispersity. With recent developments, different novel methods for the fabrication of double-emulsions have been developed such as glass capillary microfluidic devices, membrane emulsification, phase inversion techniques, etc. However, findings thus far indicate that the long-term stability of double emulsions remains a crucial issue that limits their wide application in food formulations. Therefore, further research should focus on finding innovative approaches to improve the stability of double emulsions.

Zein electrospun nanofibers have poor water resistance, which restricts its applications in food preservation. To improve the water resistance of nanofibers, zein/ethyl cellulose (EC) hybrid nanofibers were prepared at different ratios. Besides, we also encapsulated cinnamon essential oil (CEO) into electrospun fibers for Agaricus bisporus preservation. As the weight ratio of EC increased from 0% (ZE-10) to 100% (ZE-01), the viscosity of electrospinning solutions gradually increased from 80.33 ± 19.23 mPa·s to 756.78 ± 22.48 mPa·s, resulting in sufficient chain entanglement for the preparation of uniform fibers. The average diameters of ZE-01, ZE-12, ZE-11, ZE-21, and ZE-10 nanofibers were 326 ± 53 nm, 267 ± 31 nm, 237 ± 51 nm, 292 ± 45 nm, and 362 ± 70 nm, respectively. The hydrogen bonds between the hydroxyl groups of ethyl cellulose and the amino groups of zein decreased the amount of free hydrophilic group, thus improving water resistance of nanofibers. Food packaging potential was evaluated using Agaricus bisporus. The zein/EC nanofibers loaded CEO significantly decreased weight loss and maintained the firmness of the Agaricus bisporus, and improved the quality of the Agaricus bisporus during storage.

In most publications concerning edible W/O/W-emulsions, the low-HLB emulsifier polyglycerol polyricinoleate (PGPR) is used to stabilize the W/O-interface in combination with a high-HLB emulsifier which stabilizes the O/W-interface. Therefore, PGPR was used as the reference low-HLB emulsifier and compared to two alternative low-HLB emulsifiers namely ammonium phosphatide (AMP) and low-HLB sucrose ester O-170. As high-HLB emulsifiers both random coil (sodium caseinate) and globular proteins (whey protein isolate) were used. Hereby, the use of WPI led to similar, high enclosed water volume fractions for all used low-HLB emulsifiers whereas the use of Na-Caseinate led to almost no enclosed water in the emulsions containing ammonium phosphatide. Finally, the influence of osmotic pressure gradients on the release of an enclosed compound was examined. Therefore, the W/O/W-emulsions were diluted in iso-, hypo- and hypertonic solutions after which the release of an enclosed marker compound was followed over time. Hereby, AMP- and O-170 stabilized W/O/W-emulsions released the enclosed marker due to swelling under hypotonic dilution whereas hyper- and isotonic dilution never led to release of the enclosed marker, regardless of the used low-HLB emulsifier.

In the present study, a well-defined set of chitosans, with different degrees of acetylation (DA) and degrees of polymerization (DP), were processed by solution electrospraying from a water-based solvent. The solution properties, in terms of surface tension, conductivity, viscosity, and pH, were characterized and related to the physico-chemical properties of the chitosans. It was observed that both DA and DP values of a given chitosan, in combination with biopolymer concentration, mainly determined solution viscosity. This was, in turn, the major driving factor that defined the electrosprayability of chitosan. In addition, the physico-chemical properties of chitosans highly influenced solution conductivity and results indicated that the chitosan solutions with low or low-to-medium values of conductivity were the most optimal for electrospraying. The results obtained here also demonstrate that a good process control can be achieved by adjusting the working conditions, i.e . applied voltage, flow-rate, and tip-to-collector distance. Finally, it was also shown that electrosprayability of chitosan with inadequate physico-chemical properties can be improved by solution mixing of very different kinds of this polysaccharide. The resultant electrosprayed submicron chitosan capsules can be applied for encapsulation of food additives and to develop bioactive coatings of interest in food packaging, where these particles alone or containing functional ingredients can be released from the package into the food to promote a health benefit.

Polyglycerol polyricinoleate (PGPR) was used as the oil-soluble surfactant and beeswax was used as the oil phase to formulate a water-in-oil (W/O) high internal phase emulsions (HIPEs) for the encapsulation and protection of probiotics. The physicochemical properties of the W/O HIPEs and the survival of the encapsulated probiotics when exposed to acidic conditions and in vitro digestion were investigated. The viability of the probiotics decreased slightly when exposed to high-speed shearing. The rheological analysis, microstructural images, physicochemical stability showed that the W/O HIPEs remained relatively stable. The survival of the probiotics loaded in the SK-HIPEs (prepared with skim milk) was much higher than in the NS-HIPEs (prepared with normal saline) during storage at 4 °C. An in vitro gastrointestinal model showed that encapsulation of the probiotics enhanced their survival. This study provides useful insights into the utilization of W/O HIPEs to improve the efficacy of probiotics in the food industry.

Food and beverages enrichment with water-insoluble health-promoting nutraceuticals is important, but technologically challenging. Sugar beet pectin (SBP) is a natural dietary fiber with high emulsifying capacity. However, its potential as a natural encapsulator of hydrophobic nutraceuticals for beverage enrichment, has hardly been explored. Curcumin is a potent antioxidant with numerous attributed health benefits, but very low aqueous-solubility. We herein explored SBP as a carrier for solubilization and protection of curcumin (CUR). Using spectrofluorimetry, the CUR-SBP binding constant determined was (6.74 ± 0.5) ∙ 10⁵M⁻¹. As CUR:SBP molar ratio increased from 14:1 to 140:1, CUR encapsulation capacity increased from 14.5 ± 0.8 to 127.4 ± 0.4 mg CUR/gSBP, and encapsulation efficiency moderately decreased from ~100% to 86 ± 7%. The encapsulation in SBP dramatically decreased CUR particle size, from >17 μm to <0.5 μm, in average, and conferred substantial protection to CUR during simulated shelf-life, decreasing the decay rate constant ~7 fold. Therefore, SBP is a potent natural encapsulator for hydrophobic nutraceuticals for food and even clear beverage enrichment.

Micronized grape skin powder (GS) and maltodextrin-encapsulated grape skin phenolics (eGSP) were recovered from winemaking byproducts as potential food ingredients. Hygroscopicity was higher in eGSP than in GS. Both eGSP and GS had intense color and less fermented odor than the wet GS. Phenolic content, antioxidant activity and inhibitory effectiveness towards enzymes related to hyperglycemia damage were ~ double in eGSP than in GS. During storage, the rate of phenolic degradation diminished with decreasing aw from 0.75 to 0.11. Anthocyanins and proanthocyanidins were less stable than monomeric flavanols and flavonols. The rate of decrease in antioxidant activity was lower compared to the extent of phenolic degradation. At aw 0.11 no degradation was observed in eGSP, while anthocyanin and proanthocyanidin contents slightly decreased in GS (k∗103 in the range 0.69–2.94d−1). Criteria for GS and eGSP storage were defined in relation to their final uses.The conversion of winemaking by products into value added products is considered the unique strategy to overcome the cost of not recycling, including waste disposal and decontamination of affected areas. As winemaking is a seasonal activity, long-term stability of recovered byproducts is needed for their further utilization. GS and eGSP represent potential value-added food ingredients for wide-ranging applications (antioxidant, colorant, phenolic sources) and tailor-made functionalities (inhibitors of enzymes related to hyperglycemia). The results obtained led to the definition of criteria for GS and eGSP storage, which depend on their final use in foods, as illustrated by two discussed scenarios.