Dynamics of Solidification in 2% Corn Starch-Water Mixtures: Effect of Variations in Freezing Rate on Product Homogeneity

Directional solidification studies of gelatinized corn starch-water mixtures were undertaken in order to examine, in situ, the freezing behavior of this food model. The solidification rate was controlled by varying sample cell velocity as it moved from a 25°C hot stage to a -25°C cold stage. While freezing at cell velocities ≤7.5 μm/sec, starch granules were alternately pushed or entrapped by the advancing solid-liquid interface producing a segregated structure consisting of alternating high-starch and low-starch bands. At a cell velocity of 10 μm/sec, the frozen product was homogeneous. The relationship between the solid-liquid interface velocity and segregation behavior was quantified and compared to an existing model of particle-interface interactions.     

Some Essential Elements of Two Species of Boletus Grown in Cordoba (Argentina)

Edible mushrooms (Boletus tropicus and Boletus granulatus) were comparatively analyzed for eight essential elements by atomic absorption spectrophotometry. Values obtained for Fe and Mn were three times higher in B. tropicus than in B. granulatus, whereas similar values were obtained with both species for K, Ca, Zn, Mn and Cu. No Co was detected in the samples analyzed.     

MULTIVARIATE ANALYSIS FOR CLASSIFICATION OF COMMERCIAL GRAPEFRUIT JUICE PRODUCTS BY VOLATILE CONSTITUTES

Isolation of volatile constituents from fresh and processed grapefruit juice by a simple technique afforded up to 20 components in each juice type. Many of these constituents are known to contribute to grapefruit juice flavor. Multivariate analysis utilizing the concentration data of twelve constituents allowed classification of the juice samples according to processing conditions. The classification corresponded to expected flavor quality.     

Changes in Composition of Potatoes Solanum Tuberosum cv. Huinkul Stored in Clamps

Changes in tuber composition related to potato (Solanum tuberosum cv. Huinkul) storage in clamps for 120 days, were studied. Dry matter (22.5g ± 2.9) was unaffected by storage. Protein, vitamin C, total lipids and phospholipids were calculated on a 100g dry weight basis. Initial protein content (4.71 g ± 0.5) fluctuated during storage, having a similar percentage value at the end of the storage period. Vitamin C at harvest was 100 mg ± 8.1 and decreased to 55.8 mg ± 8.4 (120th day).Total lipids were 0.6g ± 0.15 and 0.25g ± 0.06 at the beginning and at the end of storage, respectively. Initial and final phospholipid content were 0.14g ± 0.02 and 0.16g ± 0.02, respectively.     

High Hydrostatic Pressure Effects on Rapid Thawing of Frozen Beef

High hydrostatic pressure (HHP) during thawing of frozen beef was investigated by measuring temperature changes in frozen beef and the pressurization fluid. Frozen ground beef sample variables were pressure levels (140, 210, 280, and 350 MPa), times (5, 15, and 30 min), sample diameters (55, 65, and 80 mm), and initial temperatures (7, 11, 18 and 22°C). Properties of cooked patties were compared between beef thawed using HHP and using conventional thawing (atmospheric pressure at 3°C). Pressures of 210 to 280 MPa provided a critical processing range that effectively thawed the beef. Sample size and initial temperature did not affect thawing rate. The lowest temperature at which the beef was efficiently thawed was-24+2°C. HHP treated beef thawed much faster than controls. HHP thawing resulted in similar color and texture to controls.     

APPLICATION OF MULTIVARIATE STATISTICAL METHODS TO DIFFERENTIATION OF RUM AGED IN TWO TYPES OF OAK BARRELS

Multivariate statistical methods have been applied to analytical data for 14 major volatile compounds collected from various rum samples, in order to differentiate rums aged in two types of oak vessels, hogshead and pipe.