Post-frying oil drainage from potato chips and french fries: a comparative study of atmospheric and vacuum drainage

This paper represents a study of the transient changes occurring in temperature, and moisture and oil contents during the so called “post-frying drainage”—which is the duration for which a product is held in the head space of the fryer after it is removed from the oil. Since most of the oil adhering to the product penetrates into the structure during this period, this paper examines the effects of applying vacuum during drainage (1.33 kPa) to maintain the product temperature consistently above the water saturation temperature corresponding to the prevailing pressure (11 °C), which potentially eliminates water condensation and prevents the occluded surface oil from penetrating into the product structure. Draining under vacuum significantly lowers the oil content of potato chips by 38% compared to atmospheric drainage. This phenomenon can be further confirmed by confocal laser scanning microscopy (CLSM) images, which show that the boundary between the core and the crust regions is clearly visible in the case of vacuum drainage, whereas in the case of atmospheric drainage, the oil is distributed throughout the structure. Unfortunately, the same approach did not reduce the oil content of French fries—the oil content of vacuum-drained product was found similar to the product obtained by draining under atmospheric pressure. This is because the reduction in oil content only occurs when there is net moisture evaporation from the product and the evaporation rate is sufficient to force out the oil from the product; this was clearly not the case with French fries. The CLSM images show that the oil distribution in the products drained under atmospheric pressure and vacuum was similar.

Combination of moderate vacuum frying with high vacuum drainage: relationship between process conditions and oil uptake

This paper explores the possibility of combining moderate vacuum frying followed by post-frying high vacuum application during the oil drainage stage, with the aim to reduce oil content in potato chips. Potato slices were initially vacuum fried under two operating conditions (140 °C, 20 kPa and 162 °C, 50.67 kPa) until the moisture content reached 10 and 15 % (wet basis), prior to holding the samples in the head space under high vacuum level (1.33 kPa). This two-stage process was found to lower significantly the amount of oil taken up by potato chips by an amount as high as 48 %, compared to drainage at the same pressure as the frying pressure. Reducing the pressure value to 1.33 kPa reduced the water saturation temperature (11 °C), causing the product to continuously lose moisture during the course of drainage. Continuous release of water vapour prevented the occluded surface oil from penetrating into the product structure and released it from the surface of the product. When frying and drainage occurred at the same pressure, the temperature of the product fell below the water saturation temperature soon after it was lifted out of the oil, which resulted in the oil getting sucked into the product. Thus, lowering the pressure after frying to a value well below the frying pressure is a promising method to lower oil uptake by the product.

Rational conversion of substrate and product specificity in a Salvia monoterpene synthase: structural insights into the evolution of terpene synthase function

Terpene synthases are responsible for the biosynthesis of the complex chemical defense arsenal of plants and microorganisms. How do these enzymes, which all appear to share a common terpene synthase fold, specify the many different products made almost entirely from one of only three substrates? Elucidation of the structure of 1,8-cineole synthase from Salvia fruticosa (Sf-CinS1) combined with analysis of functional and phylogenetic relationships of enzymes within Salvia species identified active-site residues responsible for product specificity. Thus, Sf-CinS1 was successfully converted to a sabinene synthase with a minimum number of rationally predicted substitutions, while identification of the Asn side chain essential for water activation introduced 1,8-cineole and alpha-terpineol activity to Salvia pomifera sabinene synthase. A major contribution to product specificity in Sf-CinS1 appears to come from a local deformation within one of the helices forming the active site. This deformation is observed in all other mono- or sesquiterpene structures available, pointing to a conserved mechanism. Moreover, a single amino acid substitution enlarged the active-site cavity enough to accommodate the larger farnesyl pyrophosphate substrate and led to the efficient synthesis of sesquiterpenes, while alternate single substitutions of this critical amino acid yielded five additional terpene synthases.

X-ray scattering study of the effect of hydration on the cross-beta structure of amyloid fibrils

We have investigated the effect of sample hydration on the wide-angle X-ray scattering patterns of amyloid fibrils from two different sources, hen egg white lysozyme (HEWL) and an 11-residue peptide taken from the sequence of transthyretin (TTR105-115). Both samples show an inter-strand reflection at 4.7 Å and an inter-sheet reflection which occurs at 8.8 and 10 Å for TTR105-115 and HEWL fibrils, respectively. The positions, widths, and relative intensities of these reflections are conserved in patterns obtained from dried stalks and hydrated samples over a range of fibril concentrations. In 2D scattering patterns obtained from flow-aligned hydrated samples, the inter-strand and inter-sheet reflections showed, respectively, axial and equatorial alignment relative to the fibril axis, characteristic of the cross-β structure. Our results show that the cross-β structure of the fibrils is not a product of the dehydrating conditions typically employed to produce aligned samples, but is conserved in individual fibrils in hydrated samples under dilute conditions comparable to those associated with other biophysical and spectroscopic techniques. This suggests a structure consisting of a stack of two or more sheets whose interfaces are inaccessible to bulk water.

Quantum mechanics studies of the tautomers of diacetylformoin, an important maillard product and odorant

Diacetylformoin (3,4-dihydroxy-3-hexene-2,5-dione) has 16 tautomers, many with several possible conformations and all have been geometry optimised using quantum mechanics at the HF/6-31+G* level. Eleven structures have been identified with energies within 10 kcal mol(-1) of the minimum energy structure. Of these eight are acyclic and three cyclic. Calculations of NMR spectra have clarified the identity of the acyclic and cyclic structures found experimentally. The mechanism for cyclisation has been investigated and transition states obtained. The lowest energy reaction path requires the loss and gain of a proton during cyclisation. (c) 2006 Elsevier B.V. All rights reserved.

Synthesis and X-ray crystal structure of the triethylammonium magnesium β-octamolybdate(VI)salt[Et3NH]2[Mg(H2O)6Mo8O26]·2H2O

[Et3NH]4[Mo8O26] reacted with MgCl2 giving the triethylammonum magnesium β-octamolybdate(VI) salt [Et3NH]2[Mg(H2O)6Mo8O26]·2H2O (3) and the triethylammonium hydronium β-octaamolybdate(VI) salt [Et3NH]3[(H3O)Mo8O26·2H2O (4), respectively. A small amount of [Et3NH]2[Mo6O269] was formed as a by-product. The salts 3 and 4 were characterized by X-ray crystallography. The [Mg(H2O)6Mo8O26]2− moiety in 3 is polymeric, with each octahedral [Mg(H2O)6]2+ ion sandwiched between two β[Mo8O26]4− ions, being hydrogen bonded to three terminal MOO oxygen atoms on one face of each β[Mo8O26]4− ion. The X-ray crystal structure of 4 corresponds to the reported previously. IR and conductivity data are given for 3 and 4.

Synthesis and reactions of [Et3NH]4[Mo8O6]: X-ray crystal structure of [Et3NH]3[NaMo8O26]

[Et3NH]4[Mo8O26] (1) was prepared by reacting triethylamine with either molybdenum trioxide dihydrate or with a solution of ammonium molybdate in aqueous HCl. An aqueous solution of complex 1 reacted with an excess of sodium chloride to give a mixture of [Et3NH]3[NaMo8O26] (2) and [Et3NH]2[Mo6O19] (3). Complex 2 was also formed on reacting sodium molybdate with triethylamine in aqueous HCl. In the reaction of 1 with potassium chloride the nature of the product obtained was critically dependent upon reaction time. After a 5.5 h reflux period a mixture of [Et3NH]3[KMo8O26] (4) and 3 was obtained, whereas upon prolonged reflux (24 h) only K4Mo8O26 · H2O (5) was precipitated. The X-ray crystal structure of 2 shows it to be polymeric, with each Na+ ion sandwiched between two β[Mo8O26]4− ions. Four oxygen atoms on one face of each β[Mo8O26]4− ion are coordinated to a Na+ ion, and four oxygens from the opposite face are bonded to the next Na+ ion in the polymer chain. This produces a zig-zag arrangement of Na+ ions throughout the molecular structure. Spectral, conductivity and voltammetry data are given.

Alkenyl derivatives of the metals. Oxidative addition to intermediate tin(II) alkenyls; isolation, and crystal and molecular structure of n-butyltris(triphenylethenyl)tin(IV)

Reaction of tin(II) chloride with Li(CPhCPh2) at –78 °C in diethyl ether–hexane–tetrahydrofuran affords a deep red solution whose colour fades on warming, and which we believe contains the (unstable) first dialkenyltin(II) species. The latter survives long enough at low temperatures to undergo intermolecular oxidative addition, and one such adduct leads ultimately to the formation of Sn(CPhCPh2)3Bun, which has been fully characterised including a crystal and molecular structure study. The mechanism of formation of the final product has been examined and results are reported.

The impact of price promotions on producer strategies in markets with large product heterogeneity

Although current research indicates that increasing the number of options has negative effects on the cognitive ability of consumers, little understanding has been given to the consequences on producers and their strategic behavior. This article tests whether a large portfolio of products is beneficial to producers by observing UK consumer response to price promotions. The article shows that discounts induce mainly segment switching (74% of the total impact), with a limited effect on stockpiling (26%) and no impact on purchase incidence. Consequently, consumers prefer to “follow the discount” rather than purchase multiple units of the same wine. This result seems to explain the current structure of the market, and suggests that discounts may conflict with segment loyalty, a situation that disfavors producers, particularly in very populated segments. Results also casts doubts on the economic sustainability of competition based on an intense product differentiation in the wine sector.

Synthesis, crystal structure, and magnetic properties of a very rare double μ-1,1-azido- and a μ-1,1-(OMe)-bridged FeIII dimer containing a N,N,O-donor tridentate Schiff base ligand

Two new Fe-III complexes, [Fe2L2(mu-OMe)(2)(NCS)(2)] (1) and [Fe2L2(mu-N-3)(2)(N-3)(2)] (2), have been synthesized using a N,N,O-donor tridentate Schiff base ligand HL {2-[(2-dimethylaminoethylimino)methyl]phenol}, the condensation product of salicylaldehyde and N,N-dimethyl-1,2-diaminoethane. The complexes were characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. Both crystal structures are centrosymmetric dimers containing two Fe-III atoms, which are bridged in compound 1 by two methoxy anions and in compound 2 by two mu-1,1-azides. The chelating tridentate Schiff base and a terminal thiocyanato (for 1) or azido (for 2) group complete the hexacoordination of the distorted octahedral environment of each iron center. The magnetic properties of compound 1 show the presence of antiferromagnetic exchange interactions mediated by double methoxy bridges (J = -29.45 cm(-1)). Compound 2 shows the presence of very weak ferromagnetic exchange interactions mediated by double mu-1,1-N-3 bridges (J = 1.08 cm(-1)).

Structure and magnetic properties of a tetranuclear Cu(II) complex containing the 2-(pyridine-2-yliminomethyl)-phenol ligand

A tetranuclear Cu(II) complex [Cu4L4(H2O)4](ClO4)4 has been synthesized using the terdentate Schiff base 2-(pyridine-2-yliminomethyl)-phenol (HL) (the condensation product of salicylaldehyde and 2-aminopyridine) and copper perchlorate. Chemical characterizations such as IR and UV/Vis of the complex have been carried out. A single-crystal diffraction study shows that the complex contains a nearly planar tetranuclear core containing four copper atoms, which occupy four equivalent five-coordinate sites with a square pyramidal environment. Magnetic measurements have been carried out over the temperature range 2–300K and with 100Oe field strengths. Analysis of magnetic susceptibility data indicates a strong antiferromagnetic (J1=−638cm−1) exchange interaction between diphenoxo-bridged Cu(II) centers and a moderate antiferromagnetic (J2=−34cm−1) interaction between N–C–N bridged Cu(II) centers. Magnetic exchange interactions (J’s) are also discussed on the basis of a computational study using DFT methodology. The spin density distribution (singlet ground state) is calculated to visualize the effect of delocalization of spin density through bridging groups.

Optimization of a sponge cake formulation with inulin as fat replacer: structure, physicochemical, and sensory properties

The effects of several fat replacement levels (0%, 35%, 50%, 70%, and 100%) by inulin in sponge cake microstructure and physicochemical properties were studied. Oil substitution for inulin decreased significantly (P < 0.05) batter viscosity, giving heterogeneous bubbles size distributions as it was observed by light microscopy. Using confocal laser scanning microscopy the fat was observed to be located at the bubbles’ interface, enabling an optimum crumb cake structure development during baking. Cryo-SEM micrographs of cake crumbs showed a continuous matrix with embedded starch granules and coated with oil; when fat replacement levels increased, starch granules appeared as detached structures. Cakes with fat replacement up to 70% had a high crumb air cell values; they were softer and rated as acceptable by an untrained sensory panel (n = 51). So, the reformulation of a standard sponge cake recipe to obtain a new product with additional health benefits and accepted by consumers is achieved.