ABSTRACT
Aqueous two-phase extraction (ATPE) of R-Phycoerythrin (R-PE), a fluorescent and commercially valuable protein, was carried out in two parallel schemes. In scheme-1, ATPE alone was employed, and in scheme-2, process-integration was attempted, where primary extract was subjected to precipitation before standardization of process parameters of ATPE. Scheme-1 with polyethylene glycol (PEG)-3350/potassium phosphate system has resulted in very low R-PE yield (26% w/w) without much enrichment in purity (0.3). In scheme-2, PEG-1450/potassium phosphate system (pH 6, tie-line length 12.26% and lower volume-ratio) has resulted in higher R-PE purity (0.74) with 72% yield. R-PE containing PEG-rich (top) phase was subjected to ultrafiltration, to remove phase forming components, resulting in further increase in R-PE purity (1.1). Overall enrichment in R-PE purity of 11-fold with 57% (w/w) yield and removal of about 95% of total sugars was achieved in scheme-2. Intactness of R-PE after processing was confirmed by absorbance and emission spectrum analysis.
Subject(s)
Phycoerythrin/isolation & purification , Rhodophyta/chemistry , Phosphates/chemistry , Polyethylene Glycols/chemistry , Potassium Compounds/chemistry , UltrafiltrationABSTRACT
Coconut skim milk and insoluble protein are 2 major byproducts in the production of virgin coconut oil. Coconut skim milk was homogenized along with insoluble protein and spray dried to obtain a value-added product, namely, coconut protein powder (CPP). This study deals with the storage study of CPP under different conditions (refrigerated [control], ambient and accelerated). CPP samples were withdrawn periodically at designated intervals of 15 d for accelerated and control, and 30 d for ambient condition. CPP stored at different conditions exhibited marginal moisture uptake (by 0.74 % w/w for control, 0.76 % w/w for ambient, and 1.26 % w/w for accelerated condition) and as a result, had very little effect on the functional properties of the powder. Withdrawn CPP was tested for sensory quality aspects and subjected to instrumental analysis as well. Withdrawn CPP was incorporated as a milk substitute in dessert (Kheer). Quantitative descriptive analysis of the powder and product (Kheer) showed no significant difference in attributes of CPP during the storage period of 2 mo. Electronic nose analysis revealed that CPP samples were not much different with respect to aroma pattern matching, respectively.
Subject(s)
Cocos/chemistry , Evaluation Studies as Topic , Food Storage/methods , Plant Proteins/chemistry , Adult , Coconut Oil , Food Packaging , Food Preservation/methods , Humans , Middle Aged , Odorants/analysis , Plant Oils/chemistry , Powders , Taste , TemperatureABSTRACT
Scale-up of aqueous two-phase extraction, which is useful in the isolation and purification of certain bioproducts, is limited by the slow demixing rates of the two aqueous phases. Electrokinetic demixing has been shown to increase by more than 5-fold the demixing rates of systems up to 100 mL in volume in a manner that depends on field strength, field polarity, pH, and phase composition. The present study is an attempt to relate demixing rates to droplet electrokinetic mobilities which were measured microscopically and inferred from demixing data. A clear dependence of demixing rate was observed on drop electrophoretic mobility and pH. The electrophoretic mobility of individual phase droplets suspended in the other phase was measured for poly(ethylene glycol)/Dextran systems using a microelectrophoresis unit and compared with mobilities predicted by electrokinetic theory. We confirmed earlier reports that the droplet electrophoretic mobility increased with increasing drop diameter and explained this increase on the basis of an internal electroosmotic flow model. Effective electrophoretic mobilities were estimated from electrokinetic demixing data in a 100-mL column and compared with predicted as well as experimentally measured values of electrophoretic mobility. The mobilties increased with increased phosphate ionization due to change in pH irrespective of the sign (or polarity) of the applied electric field. The electroosmotic flow model could explain satisfactorily the following two paradoxes: (1) the direction of migration of drops is the opposite of that predicted by colloid electrokinetics and (2) the phase demixing rate increased irrespective of the sign of the applied electric field.
