GRAIN SORGHUM WAX AS AN EDIBLE COATING FOR GELATIN-BASED CANDIES1

Gelatin-based candies were coated with medium chain triglyceride (MCT) oil or MCT oil combined with grain sorghum or carnauba wax (8.7% w/w of oil). Compared with uncoated samples, oil/sorghum wax and oil/carnauba wax coatings were equally effective in reducing protein solubility of candies in water (25C) and differences between initial and final diameters of candies subjected to melting. At 0, 5, and 10 days of storage (over calcium sulfate), the candies were evaluated by sensory panelists for surface reflection, pink color, clarity, chalkiness, firmness, adhesiveness, chewiness, cohesiveness, sweetness, sourness, fruit flavor, off-flavor, and aftertaste. Firmness, adhesiveness, chewiness, cohesiveness, and sourness scores increased (P<0.05) linearly with storage time. Samples treated with sorghum or carnauba wax were less shiny, more opaque, chalkier, and had more intense off-flavor and aftertaste than uncoated samples. Samples treated with the laboratory-extracted sorghum wax rated lower than carnauba wax-treated samples for surface reflection, clarity, chalkiness, off-flavor, and aftertaste.     

Ultraviolet Radiation Affects Physical and Molecular Properties of Soy Protein Films

Films were cast from heated, alkaline aqueous solutions of soy protein (5 g/100 mL water) and glycerin (50% w/w of protein). Control and ultraviolet (UV) irradiated (13.0, 25.9,38.9, 51.8, 77.8, or 103.7 J/m²) films were evaluated for tensile strength (TS), elongation at break (E), water vapor permeability (WVP), and Hunter L, a, and b color values. TS increased (p<0.05) linearly while E decreased linearly with UV dosage. WVP was not affected (P>0.05) by UV irradiation. UV treatment intensified the yellowish coloration of films (increased +b values). SDS-PAGE patterns for UV-treated samples revealed bands of aggregates, increasing in intensity with UV dosage, which were absent in control samples. These changes suggested UV-induced cross-linking in films.     

QUALITY EVALUATION OF DEEP-FAT FRIED ONION RINGS1

Battered and breaded onion rings were deep-fat fried at 170 or 190C for 30, 45, or 60s and subjected to several physical tests and to an overall desirability sensory evaluation. Hunter a color values (redness), specific shear force, and toughness increased (p < 0.01) with both frying temperature and frying time. Onion rings deep-fat fried at 190C for 60s had the highest mean overall desirability sensory score. Onion moisture content and coating redness were positively (p < 0.05) correlated with overall desirability. Coating moisture content and coating fat content were negatively (p < 0.05) correlated with overall desirability.     

Mechanical and Barrier Properties of Egg Albumen Films

Films were cast and dried from heated, alkaline aqueous egg albumen solutions containing glycerin (GLY) at 30, 40, or 50% w/w of protein, polyethylene glycol (PEG) at 50 or 60%, or sorbitol (S) at 50 or 60% as plasticizers. PEG-plasticized (60%) films also were prepared by substituting 10, 30, 50, or 70% of albumen with yolk solids. Film tensile strength (TS), elongation at break (E), water vapor permeability (WVP), and Hunter color values were measured. At a plasticizer content of 50%, films with S had the lowest WVP while films with PEG had the greatest E. S- and PEG-plasticized films had greater TS than GLY-plasticized films. Yolk solids decreased film TS, E, and WVP while increasing film yellowness.     

Temperature Effect on Oxygen Permeability of Edible Protein-based Films

Edible films from corn zein, wheat gluten, and wheat gluten/soy protein isolate (2.1:0.9) were produced and their oxygen permeabilities were determined at 7, 15, 25, and 35°C under 0% relative humidity. Mean oxygen permeability values for the 3 films were in the range of 1.8–11.2, 0.9–6.1, and 0.6–3.8 amol/m.s.Pa, respectively. Data for all 3 films showed very good agreement with the Arrhenius activation energy model. No structural transitions were indicated within these films in this temperature range. Calculated activation energy values for the oxygen permeation process were 11.1, 11.9, and 10.8 kcal/mol, respectively. Comparisons with some non-protein edible coatings and plastic packaging materials showed dry protein films were very efficient oxygen barriers.