Buddhi P. Lamsal

REVIEW: Zein Extraction from Corn, Corn Products, and Coproducts and Modifications for Various Applications: A Review

ABSTRACT Corn can be fractioned to produce starch, fiber, oil, and protein in relatively pure forms. The corn kernel contains 9–12% protein, but half of this is an industrially useful protein called zein. Dry milled corn (DMC), corn gluten meal (CGM), and distillers dried grains with solubles (DDGS) are all coproducts from corn that contain zein and are used for zein extraction. Because it is insoluble in water, zein has found uses in many products such as coatings, plastics, textiles, and adhesives. Newer applications are taking advantage of zeins biological properties for supporting growing cells, delivering drugs, producing degradable sutures, and producing biodegradable plastics. This review covers zein characteristics and nomenclature, past and current practices in processing and extraction of zein from corn products and coproducts, and the modifications of zein for various applications.

Production, health aspects and potential food uses of dairy prebiotic galactooligosaccharides

Galactooligosaccharides are sugars composed of 3-10 molecules of galactose and glucose via a transgalactosylation reaction mediated by the enzyme β-galactosidase. Prebiotics are non-digestible food ingredients that pass through the upper digestive system relatively intact and ferment in the lower colon, producing short-chain fatty acids that support the growth of supplemented or indigenous colonic microbiota. Galactooligosaccharides and other prebiotic ingredients are increasingly being recognized as useful dietary tools for the modulation of the colonic microflora toward a healthy balance. Galactooligosaccharides compare well to other oligosaccharides in terms of their prebiotic, immunomodulation, and functional properties in foods. This review elucidates the galactooligosaccharide production process from refined lactose and/or cheese whey permeates, galactooligosaccharide market share and economic value, their health properties, and potential food applications.

Ultrasound improved ethanol fermentation from cassava chips in cassava-based ethanol plants.

The effects of ultrasound and heat pretreatments on ethanol yields from cassava chips were investigated. Cassava slurries were sonicated for 10 and 30 s at the amplitudes of 80, 160, and 320 microm(pp) (peak to peak amplitude in microm) corresponding to low, medium, and high power levels, respectively. The sonicated and non-sonicated (control) samples were then subjected to simultaneous liquefaction-saccharification and ethanol fermentation. Cassava starch-to-ethanol conversion efficiencies showed that higher ethanol yields were directly related to sonication times, but not to power levels. Significantly higher ethanol yields were observed only for sonicated samples at the high power level. The ethanol yield from the sonicated sample was 2.7-fold higher than yield from the control sample. Starch-to-ethanol conversion rates from sonicated cassava chips were also significantly higher; the fermentation time could be reduced by nearly 24 h for sonicated samples to achieve the same ethanol yield as control samples. Thus, ultrasound pretreatment enhanced both the overall ethanol yield and fermentation rate. When compared to heat-treated samples, the sonicated samples produced nearly 29% more ethanol yield. Combined heat and ultrasound treatment had no significant effect on overall ethanol yields from cassava chips. Ultrasound is also preferable to heat pretreatment because of lower energy requirements, as indicated by energy balances. Integration of ultrasound application in cassava-based ethanol plants can significantly improve ethanol yields and reduce the overall production costs.

The Beneficial Use of Cereal and Cereal Components in Probiotic Foods

Cereals and cereal components can be used as fermentation substrates for probiotic organisms imparting prebiotic effects. Consumer interest in healthy functional foods has resulted in the need for food products with versatile health-benefiting properties. The conventional choice for probiotic food applications has been dairy-based products, but whole grain-based probiotic functional foods have debuted in Japan and Europe. In the US, pro- and prebiotics are mainly marketed as dietary supplements, but are moving towards inclusion in the diet as mainstream foods. Cereal constituents, such as wheat bran-based ingredients fermented with probiotics, would enhance consumer health with the benefits of probiotics, bran fiber, and healthful bioactive components.

Bioenergy and biofuel from biowastes and biomass.

This book attempts to provide an in-depth compilation of relevant technical information on several aspects of biofuel and bioenergy production ... it can serve as a useful quick reference for consulting engineers. It is also a good introductory resources for advanced students, researchers, instructors, decision makers, and professionals in the biofuel and bioenergy field. Recommended. —A.C. Sheth, emeritus, University of Tennessee Space Institute, Choice: Current Reviews for Academic Libraries, December 2010.

Production and characterization of microbial biosurfactants for potential use in oil-spill remediation.

Two biosurfactants, surfactin and fatty acyl-glutamate, were produced from genetically-modified strains of Bacillus subtilis on 2% glucose and mineral salts media in shake-flasks and bioreactors. Biosurfactant synthesis ceased when the main carbohydrate source was completely depleted. Surfactin titers were ∼30-fold higher than fatty acyl-glutamate in the same medium. When bacteria were grown in large aerated bioreactors, biosurfactants mostly partitioned to the foam fraction, which was recovered. Dispersion effectiveness of surfactin and fatty acyl-glutamate was evaluated by measuring the critical micelle concentration (CMC) and dispersant-to-oil ratio (DOR). The CMC values for surfactin and fatty acyl-glutamate in double deionized distilled water were 0.015 and 0.10 g/L, respectively. However, CMC values were higher, 0.02 and 0.4 g/L for surfactin and fatty acyl-glutamate, respectively, in 12 parts per thousand Instant Ocean®[corrected].sea salt, which has been partly attributed to saline-induced conformational changes in the solvated ionic species of the biosurfactants. The DORs for surfactin and fatty acyl-glutamate were 1:96 and 1:12, respectively, in water. In Instant Ocean® solutions containing 12 ppt sea salt, these decreased to 1:30 and 1:4, respectively, suggesting reduction in oil dispersing efficiency of both surfactants in saline. Surfactant toxicities were assessed using the Gulf killifish, Fundulus grandis, which is common in estuarine habitats of the Gulf of Mexico. Surfactin was 10-fold more toxic than fatty acyl-glutamate. A commercial surfactant, sodium laurel sulfate, had intermediate toxicity. Raising the salinity from 5 to 25 ppt increased the toxicity of all three surfactants; however, the increase was the lowest for fatty acyl-glutamate.

Effect of corn preparation methods on dry-grind ethanol production by granular starch hydrolysis and partitioning of spent beer solids

Two corn preparation methods, rollermill flaking and hammermill grinding, were compared for efficient processing of corn into ethanol by granular starch hydrolysis and simultaneous fermentation by yeast Saccharomyces cerevisiae. Corn was either ground in a hammermill with different size screens or crushed in a smooth-surfaced rollermill at different roller gap settings. The partitioning of beer solids and size distribution of solids in the thin stillage were compared. The mean particle diameter d(50) for preparations varied with set-ups and ranged between 210 and 340 μm for ground corn, and 1180-1267 μm for flaked corn. The ethanol concentrations in beer were similar (18-19% v/v) for ground and flaked preparations, however, ethanol productivity increased with reduced particle size. Roller versus hammermilling of corn reduced solids in thin stillage by 28%, and doubled the volume percent of fines (d(50) ∼ 7 μm)in thin stillage and decreased coarse (d(50) ∼ 122 μm) by half compared to hammermilling.

Development of New Method for Extraction of α-Zein from Corn Gluten Meal Using Different Solvents

ABSTRACT A modified procedure for the extraction of α-zein from corn gluten meal was developed and compared against a commercial extraction method. The modification involved raising the concentration of alcohol in solvent and removing the precipitate by centrifugation. Five organic solvent mixtures were compared using the modified extraction procedure developed along with the reductant sodium bisulfite and NaOH. The modified procedure precipitated most of the non-α-zein protein solids by increasing the concentration of alcohol. The supernatant had α-zein-rich fraction, resulting in higher yield of α-zein than the commercial method when cold precipitated. The commercial extraction procedure had a zein yield of 23% and protein purity of 28% using 88% 2-propanol solvent. The three best solvents, 70% 2-propanol, 55% 2-propanol, and 70% ethanol, yielded ≈35% of zein at protein purity of 44% using the modified extraction procedure. Zeins extracted using the novel method were lighter in color than the commercial...

Characterization of Extruded and Toasted Milk Protein Concentrates

Important functional properties of milk protein concentrate with 80% protein (MPC80), modified with low- and high-shear extrusion, or low-temperature toasting were compared. The effect of high- and low-shear profile screws in a corotating twin-screw extruder, and 4 different ramped temperature profiles with die temperatures of 65, 75, 90, and 120 °C were compared. Extrudates were pelletized, dried, and ground to a fine powder. Toasting was done at 75 and 110 °C for 4 h for milk protein modification. Extruded and toasted MPC80 had reduced protein solubility and surface hydrophobicity. Extrusion decreased water-holding capacity (WHC). Toasted MPC80 had increased WHC when treated at 75 °C, but WHC decreased when heated at 110 °C. The treatments had no strong influence on gel strength. Reduced and nonreduced sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed peptide structural changes that occurred due to processing, especially for whey proteins. Results are discussed in terms of potential for application of extruded or toasted MPC80 in high-protein nutrition bar applications.

Instrumental and Sensory Texture Attributes of High‐Protein Nutrition Bars Formulated with Extruded Milk Protein Concentrate

Previous instrumental study of high-protein nutrition (HPN) bars formulated with extruded milk protein concentrate (MPC) indicated slower hardening compared to bars formulated with unmodified MPC. However, hardness, and its change during storage, insufficiently characterizes HPN bar texture. In this study, MPC80 was extruded at 2 different conditions and model HPN bars were prepared. A trained sensory panel and instrumental techniques were used to measure HPN bar firmness, crumbliness, fracturability, hardness, cohesiveness, and other attributes to characterize texture change during storage. Extrusion modification, storage temperature, and storage time significantly affected the instrumental and sensory panel measured texture attributes. The HPN bars became firmer and less cohesive during storage. When evaluated at the same storage conditions, the texture attributes of the HPN bars formulated with the different extrudates did not differ significantly from each other. However, textural differences were noted most of the time between the control and the HPN bars formulated with extruded MPC80. An adapted HPN bar crumbliness measurement technique produced results that were correlated with sensory panel measured crumbliness (r = 0.85) and cohesiveness (r = -0.84). Overall, the HPN bars formulated with extruded MPC80 were significantly softer, less crumbly, and more cohesive than the control during storage.