Reactive supercritical fluid extrusion (RSCFX) process at acidic condition (pH 3.0) was used to generate texturized whey protein concentrate (TWPC) and the impacts of process temperature on product's physicochemical properties were evaluated. TWPC extruded at 50 and 70 °C formed soft-textured aggregates with high solubility than that extruded at 90 °C that formed protein aggregates with low solubility. Total free sulfhydryl contents and solubility studies in selected buffers indicated that TWPC is primarily stabilized by noncovalent interactions. Proteins texturized at 90 °C showed an increased affinity for 1-anilinonaphthalene-8-sulfonate (ANS) and a decreased affinity for cis-parinaric acid (CPA), indicating changes in protein structure. Water dispersion of TWPC at room temperature showed thickening function with pseudoplastic behavior. Secondary gelation occurred in TWPC obtained at 50 and 70 °C by heating the cold-set gels to 95 °C. TWPC texturized at 90 °C produced cold-set gels with good thermal stability. Compared to control, TWPC formed stable oil-in-water emulsions. Factors such as degree of protein denaturation and the balance of surface hydrophobicity and solubility influenced the heat-and cold-gelation and emulsifying properties of the protein ingredients. TWPC generated by low and high temperature extrusions can thus be utilized for different products requiring targeted physicochemical functionalities.

a b s t r a c tTexturized whey protein powder (tWPC) produced by supercritical fluid extrusion process was used to stabilize butter and corn oil emulsions. The stability of emulsions prepared at various oil concentrations and storage temperatures was investigated. Emulsion morphology was observed by CLSM and quantified for size distribution of oil droplets while rheological properties were examined to establish their stability. All corn oil-based emulsions were stable against droplet coalescence during storage. However, the stability of butter oil-based emulsions was significantly influenced by storage temperatures and oil concentrations. Emulsions with higher elasticity were obtained by raising the oil concentration. Corn oil emulsions were far less sensitive to variations in storage temperature than emulsions based on butter oil. tWPC have a potential for uses in a very large set of food emulsions from low to high fat content and from Newtonian consistency to elastic, solid like materials such as salad dressings, light mayonnaises, fillings, sandwich spread and spreadable butter.

Apparent viscosity (η a) of texturized whey protein concentrate (tWPC80) produced using supercritical fluid extrusion process was compared with commercial WPC-80 as a function of pH (3.0 to 9.0) and heating temperatures (25 to 80 • C). The tWPC80 exhibited shear thinning behavior and yielded 2 to 10-folds higher η a than commercial WPC-80 at all pH and temperatures studied. The η a of tWPC80 decreased as pH was increased from 3.0 to 9.0. The η a of both samples was always higher at pH 3.0 than at pH 7.0 due to acid-induced aggregation in the former. The ability of the tWPC80 to perform as a food thickening agent was also compared with other commercial thickeners. The tWPC80 offers as a desirable ingredient for many food formulations currently utilizing starches and polysaccharides as texture modifying agents.

Bananas are fruits that quickly turn brown after being peeled or cooked. The browning reaction reduces the quality of the appearance and shelf life of banana jam. Therefore, this study was aimed to evaluate the effect of chemical blanching and anti-browning agents on reducing browning reactions and maintaining the quality of banana jam during storage. In this study, Musa paradisiaca cv. Nipah was used to produce banana jam. The banana jam was prepared using three different treatments. The first treatment was prepared without hot water blanching treatment and with the addition of ascorbic acid and sodium metabisulphite. The jam was prepared with banana pulp, sugar, citric acid, and pectin. This treatment act as a control. The banana jam for the second and third treatments was prepared using the same ingredients as treatment one. In the second treatment, the sliced banana was blanched in hot water (80°C) for 10 mins, whereas in treatment three, the banana slices were dipped into 1.5% of ascorbic acid solution at 80°C for 10 mins. During the cooking process, 0.1% of sodium metabisulphite was added into the jam, for treatments two and three. The jam was cooked until the temperature reached 105°C and the total soluble solids range from 68 - 70°Bx. The banana jam was filled in glass jars, sterilized in a hot water bath at 80°C for 10 mins, cooled to 27°C (room temperature) before being stored at room temperature. The analysis observed were pH, total soluble solids, titrable acidity, colour, browning index, and textural properties. The samples were stored at room temperature for 60 days. The observations were made every 15 days for two months. After 60 days of storage, all treatments showed positive changes and a significant difference (p<0.05) in physicochemical and texture analyses. Overall, hot water blanching and chemical treatments significantly reduced the browning reaction in the banana jam. Therefore, treatment three had the best ability to slow down the browning reaction and deterioration rate of banana jam during room temperature storage.