THE USE OF EOS NANOEMULSION TO DEVELOP ACTIVE EDIBLE FILMS OFFERS A NEW WAY TO MODIFY TRANSPORT PROPERTIES AND TO RELEASE ACTIVE COMPOUNDS WHILE IMPROVING MECHANICAL RESISTANCE, TRANSPARENCY, AND ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY. THE AIM OF THIS STUDY WAS TO STUDY THE INFLUENCE OF HOMOGENIZATION CONDITIONS AND CARVACROL CONTENT ON THE MICROSTRUCTURE AND PHYSICAL PROPERTIES OF EDIBLE NANOEMULSIFIED CHITOSAN FILMS. FILM-FORMING EMULSIONS (FFE) WERE PREPARED WITH CHITOSAN (1.5%), TWEEN 80 (0.5%), AND CARVACROL (0.25%, 0.5%, AND 1.0%); TWO HOMOGENIZATION METHODS WERE USED (ROTOR-STATOR AND ROTOR-STATOR FOLLOWED BY HIGH-PRESSURE HOMOGENIZATION). FILM INTERNAL AND SURFACE MICROSTRUCTURE WAS CHARACTERIZED BY SCANNING ELECTRON MICROSCOPY (SEM) AND FILM PHYSICAL PROPERTIES, SUCH AS MECHANICAL, OPTICAL, AND WATER BARRIER, WERE EVALUATED. RESULTS SHOWED THAT THE HIGH-PRESSURE HOMOGENIZATION METHOD PROMOTED A SIGNIFICANT CHANGE ON FILM MICROSTRUCTURE, LEADING TO IMPROVED PROPERTIES. CARVACROL DROPLETS WERE SMALLER AND HOMOGENEOUSLY DISTRIBUTED IN THE FILM WHEN 0.5% (V/V) CARVACROL WAS INCORPORATED (1:1 TWEEN 80: CARVACROL RATIO). AS A CONSEQUENCE, EMULSIFIED FILMS OBTAINED AT HIGH PRESSURE WERE LESS OPAQUE, HAD GREATER ELONGATION, AND HAD A LOWER PERMEABILITY TO WATER VAPOR THAN THOSE OBTAINED BY THE ROTOR-STATOR METHOD. THEREFORE, HIGH-PRESSURE HOMOGENIZATION IS A GOOD METHOD TO OBTAIN EDIBLE EMULSIFIED FILMS WITH DESIRABLE PROPERTIES FOR FOOD PRESERVATION.

TO PROVIDE THEIR HEALTH EFFECT, PROBIOTICS NEED TO MAINTAIN THEIR VIABILITY, ADHERE TO THE INTESTINAL EPITHELIUM, AND COLONIZE IT WITHOUT LOSING THEIR PROBIOTIC PROPERTIES. IN THE PRESENT STUDY, LACTOBACILLUS CASEI WAS ENCAPSULATED IN A DOUBLE EMULSION AND THEN COATED WITH ALGINATE AND CHITOSAN USING THE LAYER-BY-LAYER ELECTROSTATIC DEPOSITION TECHNIQUE. THE SURVIVAL RATE AND FUNCTIONAL PROPERTIES OF L. CASEI (CHOLESTEROL ASSIMILATION, SURFACE HYDROPHOBICITY, AUTO-AGGREGATION, AND CO-AGGREGATION) WERE EVALUATED AFTER THE FREEZE-DRYING PROCESS AND DURING THE TRANSIT THROUGH THE SIMULATED GASTROINTESTINAL TRACT. RESERVOIR TYPE MULTILAYER MICROCAPSULES WITH A SMALL PARTICLE SIZE (6.2-12.2 ?M) WERE OBTAINED. FREEZE-DRIED MICROCAPSULES MAINTAINED THE INITIAL CELL COUNT (9.4 LOG UFC/G) WITHOUT AFFECTING ITS FUNCTIONAL PROPERTIES. THE RESISTANCE OF L. CASEI CELLS TO THE CONDITIONS OF SALIVARY, GASTRIC, AND INTESTINAL DIGESTION WAS NOTICEABLY IMPROVED WHEN INCREASING THE NUMBER OF LAYERS IN THE MICROCAPSULES, ESPECIALLY WHEN THEY WERE COATED WITH ALGINATE AND CHITOSAN. THE ALGINATE-CHITOSAN LAYERS PROVIDED ADDITIONAL PROTECTION TO L. CASEI CELL MEMBRANES, SUBSTANTIALLY PRESERVING THE CHOLESTEROL ASSIMILATION ABILITY, SURFACE HYDROPHOBICITY, AUTO-AGGREGATION, AND CO-AGGREGATION OF L. CASEI AFTER SIMULATED IN VITRO DIGESTION. THIS ENCAPSULATION METHOD NOT ONLY GUARANTEES THE PRESENCE OF THE PROBIOTIC IN THE GASTROINTESTINAL TRACT, BUT IT DOES NOT LOSE ITS PROBIOTIC PROPERTIES AND ENSURES THAT IT EXERTS ITS PROBIOTIC EFFECT.

CURCUMIN IS A STRONG NATURAL ANTIOXIDANT COMPOUND, BUT ITS USE AS A NUTRACEUTICAL INGREDIENT IS LIMITED DUE TO ITS LOW WATER SOLUBILITY AND POOR CHEMICAL STABILITY. THIS STUDY AIMS TO ELUCIDATE THE KEY COLLOIDAL ASPECTS DETERMINING THE PHYSICAL STABILITY AND ANTIOXIDANT ACTIVITY OF EMULSIFIED CURCUMIN, SPECIFICALLY FOCUSING ON THE EFFECT OF THE INTERFACIAL STRUCTURE OF CURCUMIN MULTILAYER EMULSIONS. CURCUMIN DISSOLVED IN COCONUT OIL WAS ENCAPSULATED IN MULTILAYER EMULSIONS PREPARED BY LAYER-BY-LAYER (LBL) DEPOSITION USING GELATIN (PRIMARY EMULSION), GUM ARABIC (SECONDARY EMULSION) AND TANNIC ACID (TERTIARY EMULSION) AS WALL MATERIALS. THE PRIMARY EMULSION EXHIBITED STABILITY AT HIGHER GELATIN CONCENTRATIONS (?0.5% W/V) DUE TO THE DROPLETS WERE COMPLETELY COATED BY THE BIOPOLYMER (MEAN DIAMETER, 377 NM). THE SECONDARY EMULSION WAS STABLE ONLY AT LOW GUM ARABIC CONCENTRATIONS (01% W/V, MEAN DIAMETER, 412 NM). THE TERTIARY EMULSION WAS MORE STABLE AT AN INTERMEDIATE CONCENTRATION OF TANNIC ACID (0.0004% W/V, MEAN DIAMETER, 470 NM). THE ANTIOXIDANT ACTIVITY OF EMULSIFIED CURCUMIN WAS WELL PRESERVED DURING EXPOSURE TO LIGHT FOR 6 DAYS, WHILE IT SIGNIFICANTLY DECREASED IN FREE CURCUMIN BEGINNING FROM DAY 0. IN CONCLUSION, THE CONTROL AND MODULATION OF THE INTERFACIAL LAYER PROPERTIES SEEM TO PLAY A KEY ROLE IN REGULATING THE PHYSICAL STABILITY AND ANTIOXIDANT ACTIVITY OF EMULSIFIED CURCUMIN.

AN EFFECTIVE ENCAPSULATION SYSTEM IS NECESSARY TO PROTECT LACTOBACILLUS CASEI AGAINST HARSH CONDITIONS DURING FOOD PROCESSING AND GASTROINTESTINAL PASSAGE. IN THIS STUDY, L. CASEI WAS ENCAPSULATED BY DOUBLE EMULSION COATED WITH AN OUTER LAYER OF CROSS-LINKED ALGINATE; THE EFFECT ON ITS VIABILITY AFTER FREEZE DRYING, THERMAL TREATMENT, IN VITRO DIGESTION, AND DURING STORAGE WAS EVALUATED. THE INTERFACIAL STRUCTURE OF THE MICROCAPSULES PRODUCED BY THE FORMATION OF DOUBLE EMULSION AND ALGINATE COATING IMPROVED THE PROTECTIVE FUNCTION OF L. CASEI UNDER STRESS CONDITIONS, ESPECIALLY WHEN THE ALGINATE OUTER LAYER WAS SUBJECTED TO IONIC GELATION. MICROENCAPSULATED L. CASEI ACHIEVED 97.3% ENCAPSULATION EFFICIENCY AND 98% SURVIVAL RATE AFTER THE FREEZE?DRYING PROCESS, WHILE MAINTAINING COUNTS ABOVE 107 CFU/G AT 50 AND 70 °C FOR 20 MIN. THE MICROCAPSULES PROVIDED HIGH VIABILITY IN THE INTESTINAL PHASE (106 CFU/G) AND GREATER STABILITY DURING STORAGE AT 4 °C (107 CFU/G, 17 WK). GREATER MICROCAPSULE PROTECTIVE CAPACITY CAN BE ASSOCIATED WITH INCREASED GLASS TRANSITION AND MELTING TEMPERATURES OF THE ENCAPSULATING MATRIX AND FORMATION OF A MORE COMPACT ALGINATE LAYER. THE PROPOSED ENCAPSULATION TECHNOLOGY REPRESENTS AN ALTERNATIVE TO IMPROVE L. CASEI VIABILITY UNDER STRESS CONDITIONS AND IT COULD BE USED TO DEVELOP FUNCTIONAL FOODS.