Determination of Connective-Tissue Components in Beef Using Simultaneous Equations Based on Amino-Acid Analyses

Collagen, elastin and residual actomyosin in connective tissue of some lower grades of beef were determined from the contents of hydroxy-proline, valine and glutamic acid, using three simultaneous equations based on amounts of these amino acids found in the pure proteins. The complete amino-acid profiles of the connective tissues agreed with the calculated protein compositions. Connective tissues were removed from the meat by dissection, and sequential saline extractions removed sarcoplasmic and myofibrillar proteins. Glycoproteins were removed by extraction with half-saturated calcium hydroxide; collagen, by autoclaving. Changes in composition after extraction or au-toclaving were confirmed by histological investigations.     

Competitive Adsorption Between Sodium Caseinate and Oil-Soluble and Water-Soluble Surfactants in Oil-in-Water Emulsions

Competitive adsorption between sodium caseinate and either a water-soluble surfactant, Tween 60 (polyoxyethylene sorbitan monostearate—PSM) or an oil-soluble surfactant, Span 60 (sorbitan monostearate—SM) was studied in oil-in-water emulsions. Surfactants were present during homogenization. Surface concentration of protein in freshly prepared emulsions decreased as concentration of PSM or SM increased. However, only partial displacement of protein was observed with either surfactant. The reduction in protein surface concentration was greater in the presence of PSM. Interfacial protein composition was independent of surfactant type. In the absence of surfactant, preferential adsorption of β-casein occured in emulsions containing ≤1.0 wt % protein. On addition of surfactant preference for β-casein at the interface was reduced.     

The chemical and sensorial effects of lysozyme addition to red and white wines over six months' cellar storage

Lysozyme is an enzyme with muramidase activity which can lyse Gram-positive bacteria, including wine lactic acid bacteria. This enzyme provides a practical method for delaying or preventing the growth of Oenococcus oeni and consequently the onset of malolactic fermentation during the vinification of red and white wines. This paper reports the impact of lysozyme on the chemical and sensorial properties of commercially vinified red (Cabernet Sauvignon and Shiraz) and white (Riesling) wines. The addition of lysozyme to these wines had little or no effect on the content of alcohol, free and total sulfur dioxide and titratable acidity, and pH value. The lysozyme retained 75–80% activity in the Riesling wine after six months, however no detectable activity remained in the Cabernet Sauvignon and Shiraz wines after two days. Upon addition of lysozyme to both of the red wines, a rapid initial decrease (up to 17%) in red wine colour density and phenolic content occurred in association with the formation of a light precipitate. The reduction in red wine colour was also noted by the sensory panel. When added to the Riesling wine, lysozyme did not cause an increase in browning over the six month storage time, but did induce heat instability (haze), suggesting that white wines may require protein stabilisation following treatment with lysozyme. Sensory assessment by triangle difference testing revealed that, during the six month storage period, treatment with lysozyme did not cause important changes to either the aroma or palate of the red and white wines tested.     

HPSEC with Component Analysis of Citrus and Apple Pectins After Hollow Fiber Ultrafiltration

Component analysis of high performance size-exclusion chromatograms was applied to 3.3 × concentration of citrus and apple pectins in dilute solution by ultrafiltration with a hollow fiber module fitted with a 100K membrane. Viscosities of the pectins in retained solutions were unchanged and for citrus pectin there was a 10% reduction of weight fraction of the largest-sized component at the last stage of concentration. A small proportion of apple pectin (radius of gyration = 7 nm) was recovered from one permeate by freeze-drying, and, when redissolved in water, produced large aggregates (z-average diam > 100 nm, measured by dynamic light scattering). Results can provide guidelines for use of the method during industrial pectin processing.     

POTENTIAL FOR BACTERIAL GROWTH ON THE FRESH CUT TROPICAL SQUASH, CALABAZA (CURCUBITA MOSCHATA), DURING STORAGE

Calabaza (Curcubita moschata) is a tropical squash which is gaining popularity as a specialty crop for agricultural producers in the Northeast United States. It is commonly marketed by being cut in half, wrapped in plastic and may be held unrefrigerated until sold. This method of display is essential for consumer acceptance, yet unrefrigerated storage means that some potential for food safety problems exists. Experiments were conducted to determine the potential for bacterial growth during storage of cut calabaza. Freshly cut calabaza contained between 1.3 and 4.7 log₁₀CFU/g aerobic mesophiles. By 10 h, duplicate counts from some samples exceeded 4 log₁₀ CFU/g. After 24 h of room temperature storage, total aerobic plate counts ranged from 5.2 to 7.7 log₁₀ CFU/g. Rapid bacterial growth on cut calabaza stored at room temperature indicates that these products are highly perishable, and may be able to support the growth of pathogenic bacteria, should they be introduced during the slicing process.     

Effects of Frozen Storage and Cooking on Lipid Oxidation in Chicken Meat

Fresh chicken breast and leg meat samples, which were frozen for 3 months or 6 months at −18°C, were cooked in microwave and convection ovens and then tested for levels of lipid oxidation. After 6 months storage, malonaldehyde in fat from meat samples, as measured by a TBA assay, modified to avoid sample autoxidation, increased 2.5 fold, while the fluorescence excitation (360 nm) and emission (440 nm) spectra increased an average of 34%. Fat from meat cooked in a convection oven averaged 83% higher malonaldehyde concentration and 21% higher fluorescence compared to levels before cooking. Levels of lipid oxidation products in fat from chicken breast and leg meat were not significantly different in microwave compared to convection oven cooking; but certain secondary fluorescent products were higher in meats cooked by convection oven.     

Model for photo-induced long-term drain current transients in GaAs MESFETs

A simple model is presented for the negative drain current transients observed in GaAs MESFETs when subjected to ionizing radiation. The two dominant mechanisms are proposed to be electron trapping under the Schottky gate and in the neutral semi-insulating substrate. The model is suitable for the design and evaluation of radiation-resistant GaAs MESFET integrated circuits using common electrical simulators such as SPICE3.     

Light and temperature effects on shoot fruitfulness in Vitis vinifera L. cv. Sultana: Influence of trellis type and grafting

Fruit bud initiation in Sultana is more sensitive to climatic factors than fruit bud initiation in other cultivars. This paper considers historical findings regarding the influence of light and temperature on fruit bud initiation and fruitfulness in view of modern Sultana vineyard management practices.
Past results were reviewed and confirmed by experiments in which variability in vine size and structure was introduced by grafting and modifications of trellis design. Ramsey-grafted vines were consistently less fruitful than own-rooted Sultana, possibly because of a more shaded canopy interior due to greater vegetative growth of vines grafted to Ramsey rootstock. Carbohydrate reserves of node and internode tissue in late winter between node 2 and 18 followed a similar trend along the cane as fruitfulness in the following spring.     

BELLY THICKNESS EFFECTS ON THE PROXIMATE COMPOSITION, PROCESSING, AND SENSORY CHARACTERISTICS OF BACON

This study was conducted to evaluate the effects of belly thickness on processing, sensory and visual characteristics, moisture and fat of bacon made from 45 bellies of various thicknesses. Belly thickness had a linear effect (P < 0.05) on raw, cured, and cooked weights, and water and fat content. A linear relationship (P < 0.05) was observed between belly thickness and slice integrity, appearance, and lean-to-fat ratio of bacon. Saltiness, texture and mouthfeel, bacon flavor intensity, and off-flavor intensity were unrelated to raw belly thickness.