Extraction of bovine serum albumin using nanoparticulate reverse micelles

The extraction of a relatively large molecular weight protein, bovine serum albumin (BSA), using nano-sized reverse micelles of nonionic surfactant polyoxyethylene p-t-octylphenol (Triton-X-100) is attempted for the first time. Suitability of reverse micelles of anionic surfactant sodium bis (2-ethyl hexyl) sulfosuccinate (AOT) and Triton-X-100/AOT mixture in organic solvent toluene for BSA extraction is also investigated. Although, the size of the Triton-X-100 reverse micelle in toluene is large enough to host BSA molecule in the hydraulic core, the overall extraction efficiency is found to be low, which may be due to lack of strong driving force. AOT/toluene system resulted in complete forward extraction at aqueous pH 5.5 and a surfactant concentration of 160 mM. The back extraction with aqueous phase (pH 5.5) resulted in 100% extraction of BSA from the organic phase. The addition of Triton-X-100 to AOT reduced the extraction efficiency of AOT reverse micelles, which may be attributed to reduced hydrophobic interaction. The circular dichroism (CD) spectrum of BSA extracted using AOT/toluene reverse micelles indicated the structural stability of the protein extracted

Use of reverse micellar systems for the extraction and purification of bromelain from pineapple wastes

Reverse micellar systems of CTAB/isooctane/hexanol/butanol and AOT/isooctane are used for the extraction and primary purification of bromelain from crude aqueous extract of pineapple wastes (core, peel, crown and extended stem). The effect of forward as well as back extraction process parameters on the extraction efficiency, activity recovery and purification fold is studied in detail for the pineapple core extract. The optimized conditions for the extraction from core resulted in forward and back extraction efficiencies of 45% and 62%, respectively, using reverse micellar system of cationic surfactant CTAB. A fairly good activity recovery (106%) and purification (5.2-fold) of bromelain is obtained under these conditions. Reverse micellar extraction from peel, extended stem and crown using CTAB system resulted in purification folds of 2.1, 3.5, and 1.7, respectively. Extraction from extended stem using anionic surfactant AOT in isooctane did not yield good results under the operating conditions employed

Mixed reverse micellar systems for extraction and purification of β-glucosidase

Mixed reverse micellar (MRM) systems of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and nonionic surfactants (Tween 20, Tween 80, Tween 85 and Triton X-100) in iso-octane were used for the extraction and primary purification of β-glucosidase (EC 3.2.1.21) from the aqueous extract of barley (Hordeum vulgare) for the first time. Studies are carried out with both phase transfer as well as injection mode of reverse micellar extraction, among which, injection mode is observed to be more suitable for β-glucosidase extraction. The process parameters such as concentration of surfactants and their molar ratio, type of solvent, volume of sample injected and its protein concentration, pH and ionic strength of the initial aqueous phase for forward extraction, buffer pH, concentration of hexanol and salt during back extraction are varied to maximize the extraction efficiency. The molar ratio of AOT:nonionic above 4.5:1.0 only resulted in clear phase formation and below this ratio precipitation was observed at the interface during forward extraction. Mixed reverse micelles found to solubilize almost three times more volume of water and protein than AOT alone under otherwise similar conditions. Activity recovery was found to be in the order of AOT/Tween 20 > AOT/Tween 80 > AOT/Triton X-100 > AOT/Tween 85 > AOT. MRM system of 150 mM AOT/15 mM Tween 20 has resulted in maximum activity recovery of 95.18% and degree of purification of 4.8-fold

Reverse micellar extraction of β-galactosidase from barley (Hordeum vulgare)

The reverse micellar system of sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/isooctane was used for the extraction and primary purification of β-galactosidase (EC 3.2.1.23) from the aqueous extract of barley (Hordeum vulgare) for the first time. The process parameters such as the concentration of the surfactant, the volume of the sample injected, and its protein concentration, pH, and ionic strength of the initial aqueous phase for forward extraction, buffer pH, and salt concentration for back extraction are varied to optimize the extraction efficiency. Studies carried out with both phase transfer and injection mode of reverse micellar extraction confirmed the injection mode to be more suitable for β-galactosidase extraction. The extent of reverse micellar solubilization of proteins increased with an increase in protein concentration of the feed sample. However, back extraction efficiency remained almost constant (13–14.4%), which indicates the selectivity of AOT reverse micelles for a particular protein under given experimental conditions. β-Galactosidase was extracted with an activity recovery of 98.74% and a degree of purification of 7.2-fold

Modeling of peroxidase inactivation and temperature profile during infrared blanching of red bell pepper

Infrared (IR) blanching resulted in moisture loss (~1.6%), whereas fat, crude fiber, protein and carbohydrate contents were not affected. Retention of ascorbic acid (94.3%) and β-carotene (108.4%) was found to be high after IR blanching. Inactivation of peroxidase (POD) and temperature profile in red bell pepper was predicted by employing different models. Fractional conversion model and multiple regression analysis were used to predict the POD inactivation at different temperatures (130, 150 and 170C). The time–temperature–distance relationship and multiple regression analysis were used to predict the temperature at different points (0.5, 2.5 and 4.5 mm from top) of red bell pepper subjected to IR blanching at 150C. The multiple regression analysis was found to fit well (R2 = 0.996–0.997) with the experimental values for predicting POD inactivation than fractional conversion model (R2 = 0.868–0.943). The temperature profile during blanching of red bell pepper was predicted well by using time–temperature–distance relationship (R2 = 0.996–0.999) and multiple regression analysis (R2 = 0.979–0.989)

Separation and purification of bromelain by reverse micellar extraction coupled ultrafiltration and comparative studies with other methods

Reverse micellar extraction (RME) is a promising liquid-liquid extraction technique for downstream processing of biomolecules from dilute solutions. An integrated approach of coupling RME with ultrafiltration is attempted to improve the overall efficiency of extraction and purification of bromelain from aqueous extract of pineapple core. The performance of RME is compared with aqueous two-phase extraction (ATPE), another potential liquid-liquid extraction technique and conventional ammonium sulphate precipitation technique. The reverse micellar system of cationic surfactant cetyltrimethylammoniumbromide/isooctane/hexanol/butanol used for RME resulted in an activity recovery of 95.8% and purification of 5.9-fold. The purification of bromelain increased to 8.9-fold after ultrafiltration. Alteration of aqueous phase pH during RME facilitated the differential partitioning of bromelain and polyphenoloxidase. Comparison of RME results with ATPE (activity recovery of 93.1% and purification of 3.2-fold) and the conventional ammonium sulphate precipitation (activity recovery of 82.1% and purification of 2.5-fold) indicated the improved performance of RME

Effect of additives on quality of spray-dried fructooligosaccharide powder

Fructooligosaccharide (FOS) finds its applications as an alternative sweetener in powder form. The effect of different process parameters (feed concentration, feed flow rate, inlet air temperature), different additives (maltodextrin, gums, starch), and anticaking agents (in different combinations and concentrations) during spray drying were investigated. FOS solution with 2% magnesium oxide as an additive gave a maximum powder yield (43% w/w), and the spray-dried powder size was fine and the texture was like talcum powder. Flow properties and microbial analysis were found to be satisfactory. The addition of anticaking agents did not have a significant effect either on the color of the powder or on FOS content, indicating good quality of the powder with respect to flowability, microbial load, and texture

Encapsulation of yeast (Saccharomyces cereviciae) by spray drying for extension of shelf life

The objective of the present work was to encapsulate yeast using different carrier materials and examine their efficacy in retaining viability of cells after spray drying. Slurry containing yeast cells along with known amount of carrier material (maltodextrin, corn starch, gum arabic, acacia gum, polyethylene glycol 8000, β-cyclodextrin, and skimmed milk powder, one at a time) was added and served as feed. Among these carrier materials attempted, corn starch and maltodextrin showed the best results with respect to powder yield (59%, w/w) and cell survival (80.5%), respectively. However, considering both survival and powder yield (67 and 59% w/w, respectively), corn starch was observed to be the most suitable carrier material

Mass transfer in osmotic membrane distillation

Osmotic membrane distillation is a novel athermal membrane process that facilitates the maximum concentration of liquid foods under mild operating conditions. In the present study, the effect of various process parameters such as type, concentration and flow rate of the osmotic agent; type (polypropylene membranes) and pore size (0.05 and 0.2 μm) of the membrane; temperature with respect to transmembrane flux was studied. Experiments were performed with real systems (pineapple/sweet lime juice) in a flat membrane module. Osmotic agents namely sodium chloride and calcium chloride at varying concentrations are employed. For both the osmotic agents, higher transmembrane flux was observed at maximum osmotic agent concentration. In comparison with sodium chloride, higher transmembrane flux was observed in case of calcium chloride. A mass transfer-in-series resistance model has been employed, considering the resistance offered by the membrane as well the boundary layers (feed and brine sides) in case of real systems for the first time. The model could predict the variation of transmembrane flux with respect to different process parameters