Leakage of Anthocyanins from Skin of Thawed, Frozen Highbush Blueberries (Vaccinium corymbosum L.)

Factors affecting the tendency of thawed blueberries to leak pigmented exudate were investigated. Drip and anthocyanin leakage rates (ALR) were determined spectrophotometrically. Leakage vs time curves were linear or two-phase linear, ALR varying with cultivar, ripeness, and berry condition. Dewaxing increased ALR with most cultivars. ALR did not correlate with berry anthocyanin content, surface area, or cuticle thickness. ALR and amount of drip were poorly correlated. ALR varied from berry-to-berry within samples. Leakage was observed to be nonuniform on berry surfaces, appearing at skin cracks and ruptures, the calyx area, and other point sources. An hypothesis relating leakage to skin condition, fluid accumulation, and anthocyanin content is presented.     

Efficiency in public schools: a case study in non-parametric measurement

This study illustrates the problem of efficiency measurement in stochastic input-output systems when market price data are unavailable. Efficiency comparisons by non-parametric methods are attempted for selected public elementary schools in California for 1976-77 and 1977-78. A suitable linear programming model is developed for the efficiency frontier in the input-output space, which is found to be significantly different from an average relation. This is shown to have important policy implications for improving input performance for better efficiency.     

Alkaline-Earth Tungstates: Equilibrium and Stability in the M-W-O Systems

Phase relations in the systems alkaline earth oxide-tungsten trioxide and their stability with metallic tungsten were investigated by the quenching technique using sealed capsules. In the system BeO-WO₂, no intermediate compounds were formed. Binary mixtures resulted in a eutectic at 1185°C and 37 mole % BeO. In the system MgO-WO₃, the 1:1 compound was stable and melted congruently at 1358°C. There are two crystalline modifications of this compound. The well-known wolframite-type form is stable below 1165°C. Two eutectics were found: 1120°C and 28.5 mole % MgO and 1318°C and 55.0 mole % MgO. In the systems CaO-WO₃, SrO-WO₃, and BaO-WO₃, two binary compounds are stable. The 1:1 compounds with the scheelite-type structure melt, respectively, at 1580°, 1535°, and 1475°C, and form eutectics with WO₃ at 1135°, 1073°, and 935°C, all with a eutectic composition near 75 mole % WO₃. The 3:1 compounds having the distorted (NH,)₃FeF₆-type structure melt at ∼2250°, 2225°, and 1795°C. The eutectics between these two compounds are at 1490°C and 56.5 mole % CaO, 1410°C and 57.0 mole % SrO, and 1320°C and 58.2 mole % BaO. Phase transformations to an ideal (NH₄)₃FeF₆-type structure in Sr₃WO₆ and Ba₃WO₆, were observed at 1100° and 805° C, respectively, by application of both high-temperature X-ray diffraction and DTA. At 1700°C, metallic tungsten exists in equilibrium with liquid, the alkaline earth oxides, W₁₈O₄₉, the 3:1 ternary oxides, and with combinations thereof.     

EXTENDED VALIDATION OF A SIMPLIFIED EXTRACTION AND GRAVIMETRIC DETERMINATION OF TOTAL FAT TO SELECTED FOODS

A simplified method for chloroform/methanol extraction and gravimetric determination of total fat previously published for diet composites was tested on additional foods, including milk, cheese, fried snack foods, nuts/seeds, salad dressings, baked goods, meat, fish/shellfish and fruits/vegetables. Homogenized food composites and certified reference materials (CRMs) were analyzed using the existing method involving, briefly, orbital shaking of a subsample with chloroform/methanol/buffer in specific proportions, then recovery of total lipid in the chloroform extract. For meat, fish, shrimp, cheese and fried plantains, total fat recovery was low and/or variability was high with the unmodified assay versus results from other standard total fat methods (e.g., ether extraction, acid hydrolysis) or to CRM assigned values. Reducing the sample size or adding a homogenization step during extraction resulted in relative standard deviations of < 3% for all matrices and also values consistent with those generated by other standard total fat methods and within assigned ranges for total fat in most CRMs.

PRACTICAL APPLICATIONS

The method allows for routine batch analysis of multiple samples of a range of food types with minimized hands-on time, using commonly available laboratory equipment. The resulting total lipid extract can be subdivided for analysis of various specific lipid analytes as well as for gravimetric measurement of total fat.     

The Conversion of a Boron-Containing Pyrotechnic Mix to a “Ceramic-Like” Material by Electron Beam Interaction

The transformation of a boron-containing pyrotechnic mix to a “ceramic” vitreous-like material by the impingement of an electron beam on a boron-barium chromate pyrotechnic, in a scanning electron microscope, is reported. The thickness of the “ceramic”-like material is ×250 the penetration depth for the electron beam and indicates that a self-sustaining chemical reaction was induced by interaction of the energetic material with the electron beam at temperatures well below the mix's ignition temperature of over 1000?°C. This links with earlier observations on the low-temperature liquefaction of boron to boron suboxides in an electron microscope.     

Sweetness of α-, β-, and Equilibrium Lactose Relative to Sucrose

The sweetness of α-, β-, and equilibrium lactose, measured by a trained panel using paired comparison with standard reference solutions of sucrose of concentrations from 0.50–6.50%, ranged from 30–35% that of sucrose. The sweetness of β-lactose was 105–122% that of α-lactose. The predicted swweetness of lactose at mutarotation equilibrium, calculated from sweetness values for α- and β-lactose and from the relative amounts present as determined by polarimetry, i.e., 38%α and 62%β, did not differ significantly from the experimentally determined sweetness value, indicating an absence of synergism for sweetness in mixtures of α- and β-lactose. Isosweet sucrose concentrations for three different concentrations of β- and equilibrium lactose and two concentrations of α-lactose are reported.     

Effect of nisin on the shelf-life of pasteurized double cream

Nisin was found to extend the shelf-life of pasteurized double cream if post-pasteurization contamination was eliminated. Nisin had little effect on the organoleptic properties of cream but enhanced proteolysis by Gram-negative organisms. A negative correlation was observed between nisin degradation in the cream and extension of the shelf-life. There was also a correlation between nisin degradation and the extent of proteolysis in the creams.     

Acceptance by American and Asian Consumers of Extruded Fish and Peanut Snack Products

Fish snack half-products were produced using extrusion temperatures and screw speeds of 97°C and 285 rpm, 95°C and 350 rpm, and 95°C and 220 rpm. Peanutsnack half-products were produced at 100°C and 250 rpm, 95°C and 325 rpm, and 95°C and 250 rpm. The half-products were fried at 200°C for 1.5 min and evaluated for acceptability using a 9-point hedonic scale. Temperature and screw speed influenced consumer acceptance. Aroma, flavor, and overall acceptance of fish snack products were rated significantly higher by Asian consumers(n = 30) than by American consumers (n = 30). There was no significant difference in ratings for all sensory attributes and overall acceptance of peanut snack products by Asian or American consumers.     

Neutral Salt Effects on Stability of Whey Protein Isolate Foams

Addition of 0.1 M Na₂SO₄, NaCl, or NaSCN reduced maximum overruns of whey protein isolate (WPI) by 33%, 27%, and 38%. This was attributable to an ionic effect, i.e., the ions interacted with countercharges on the proteins thereby reducing electrostatic interactions. In contrast, at high concentrations (1M), Na₂SO₄ improved foam stability by 76% compared to WPI without salt. Chloride had an intermediate effect, whereas NaSCN did not improve foam stability. Increasing Na₂SO₄ concentration (2M) improved foam stability by 127% compared to control. The relative effectiveness of salts at improving foam stability and heat stability followed the Hofmeister series (SO₄^2-??).