Texturization of Sweetened Mango Pulp: Optimization using Response Surface Methodology

Sugar added mango pulp was texturized with alginate. To optimize both the mechanical properties and thermostability of the products, an experimental design was used combined with response surface methodology. Alginate concentration was the major factor affecting mechanical properties of texturized pieces with higher strength as the gelling agent concentration increased. Furthermore, gel strength and thermostability generally increased as calcium and glucono-δ-lactone concentrations, and/or heat treatment duration increased. As large quantities of sweetened pulp were used, texturized pieces with high dry matter content and good flavor qualities were obtained.     

Sequencing Analysis of a 36·8 kb Fragment of Yeast Chromosome XV Reveals 26 Open Reading Frames Including SEC63, CDC31, SUG2, GCD1, RBL2, PNT1, PAC1 and VPH1

The complete sequence of a 36 775 bp DNA segment located on the right arm of chromosome XV of Saccharomyces cerevisiae has been determined and analysed. The sequence encodes 26 open reading frames of at least 100 amino acids. Eight of these correspond to known genes, whereas 18 correspond to new genes. The sequence has been deposited in the EMBL databank under Accession Numbers: Z75154, Z75155, Z75156, Z75157, Z75158, Z75159, Z75160, Z75161, Z75162, Z75163, Z75164, Z75165, Z75166, Z75167, Z75168, Z75169, Z75170, Z75171, Z75172, Z75173, Z75174, Z75175, Z75176, Z75177, Z75178, Z75179. © 1997 John Wiley & Sons, Ltd.     

Liposomes as Proteinase Carriers for the Accelerated Ripening of Saint-Paulin Type Cheese

The possibility of accelerated cheese ripening through addition of liposome entrapped proteinase to milk was investigated. Both enzyme encapsulation rate in liposomes and their retention in cheese were evaluated with multilamellar vesicles (MLV) and reverse-phase evaporation vesicles (REV). Using REV in Saint-Paulin type curd, no nitrogen loss was observed to the whey due to the added enzymes in liposomes. In cheese, REV produced a more progressive proteolysis during ripening than MLV did. REV addition did not lead to texture defects. Bitterness development, a critical defect in enzyme added cheese, could be delayed and minimized using REV.     

Reduction of Streptococcus thermophilus in a whey protein isolate by low moisture extrusion cooking without loss of functional properties

A whey protein isolate powder (WPI) (4–5% water) inoculated with 5x10⁵ viable Streptococcus thermophilus per g, was continuously processed in a twin screw extruder under the following conditions (barrel length = 500 or 1000 mm; screw profile = forward transport and compression elements; moisture content during extrusion = 4–5%; feed rate = 10 kg h^-1; barrel temperature ( T_b ) = 80–204°C; speed of screw rotation = 50 r.p.m.). The minimum residence time determined by pulse injection of erythrosin was 20–25 s (500 mm barrel) or 35–40 s (1000 mm barrel).
Reduction values of viable Streptococcus thermophilus of 10^4.2-fold (500 mm barrel, T_b = 143°C) or 10^4.9-fold (1000 mm barrel, T_b = 133°C) were obtained without any modification of protein solubility or gelling properties. WPI extruded at the highest barrel temperatures (182–204°C) underwent limited browning and reduction of protein solubility. Gel permeation and hydrophobic interaction chromatography of the soluble constituents did not show any aggregates of β-lactoglobulin or α-lactalbumin.
Gels prepared from control or extruded WPI ( T_b 143°C with a barrel length = 500 mm or T_b 133°C with a barrel length = 1000 mm) were identical, as judged by scanning electron microscopy and rheological evaluations.     

Continuous Gel Formation by HTST Extrusion-Cooking: Soy Proteins

The continuous production of gels of high moisture content is carried out by extrusion-cooking, with a residence time of 30-100 sec, using soy protein isolate as a model ingredient. The hot viscous extrudate can be collected in a mold, and gels upon cooling. The best texture characteristics are obtained with protein and water concentrations of 18 and 80% (wet basis), respectively, and extrusion temperatures of 150-160°C. The effects of acidification, addition of NaCl, CaCl₂ or sucrose on gel texture are investigated. Extrusion-prepared soy gels melt reversibly upon further heating (120°C) and withstand frozen storage. Their texture and micro-structure are compared to those of soy gels prepared by conventional batch heating at 100-120°C.     

The near field of an antenna surrounded by a dielectric with two teeth

The near field of an antenna surrounded by a dielectric with two teeth is studied when the ambient medium is dissipative. We use the continuity of radial power flux and the boundary conditions at each interface, but not near the discontinuity, to express this field.     

Microcoagulation of a Whey Protein Isolate by Extrusion Cooking at Acid pH

A whey protein isolate (WPI) was coagulated by thermomechanical processing in a twin screw extruder. Nonaggregated semi-solid spreads were obtained only in the pH range 3.5–3.9, at ca 20% protein (77% water), a barrel temperature of 90–100°C and a screw speed of 100–200 rpm. WPI extrusion-coagulated at pH 3.9 displayed a high nitrogen solubility (NSI) (43–47%). Electrophoresis indicated that the β-lactoglobulin constituent was entirely soluble in 1% SDS, while scanning calorimetry revealed about 82% protein unfolding. WPI extrusion-coagulated at pH 4.5–6.8 displayed lower NSI (25%), were less soluble in 1% SDS, were 88% unfolded and had grainy texture. Light microscopy, centrifugation in glycerol solutions, and laser diffractometry indicated the acid spread (pH 3.9) was composed of small coagulated particles, mean diameter 11.5 μm (volume basis).     

SOLUBILITY AND DIFFUSIVITY OF GASES IN AN ORGANIC SOLUTION OF AMINE

Solubilities and diffusivities of carbon dioxide and nitrous oxide in a mixture of toluene and isopropanol organic solution of cyclohexylamine were measured at 20°C in the range of pressures of solute from 1 to 3 bars. This was performed with an original chromatographic technique taking into account the presence of the product of the reaction.     

Continuous Restructuring of Mechanically Deboned Chicken Meat by HTST Extrusion-Cooking

The continuous restructuring of mechanically deboned chicken meat (MDM) was attempted using twin-screw extrusion-cooking at high moisture contents (50-80%), high temperatures (ca 150°C), short residence times (30-240 sec) and low pressures (below 6 bars). The hardness, cohesiveness and water-holding capacity of the nonexpanded moist extruded samples are optimal and resemble those of meat-loaf when 10-20% wheat flour or pregelatinized corn starch are added to MDM. Incorporation of 25% soy protein isolate gives a solid gel matrix containing dispersed meat particles. Scaling up this process could lead to the continuous production of simulated meat chunks or slices for use in canned or frozen dishes.     

An ethanol spray at veraison enhances colour in red wines

Aqueous ethanol (5% v/v) was sprayed onto bunches of Vitis vinifera L. cv. Cabernet Sauvignon 8–9 weeks following full flowering (controls were sprayed with water). Internal ethylene concentration in treated berries increased to a maximum within 6 hours, and berry colour subsequently increased substantially (maximum attained 2–3 weeks after spraying). Berry fresh weight at harvest was unaffected by ethanol treatment, but wine made from treated grapes showed greater colour intensity compared with control grapes.