Soybean Flour Lipoxygenase lsozyme Mutant Effects on Bread Dough Volatiles

Lipoxygenases are implicated in improvement of bread quality after addition of enzyme active soy flour. However, differences among the three major isozymes in soybeans in terms of impact on bread characteristics are not known. Differences exist among soybean lipoxygenase isozymes in terms of stability and generation of volatile flavor and aroma. Soybean flour with different lipoxygenase isozymes present might affect bread dough volatiles or defatting may affect activity of the isozymes. Full fat or defatted soy flour could be added to bread dough. Defatting selectively reduced lipoxygenase 2 activity with little effect on lipoxygenases 1 and 3. Addition of full fat soy flour from mutant isolines indicated that as with soybean homogenates, lipoxygenase 2 is mostly responsible for undesirable aroma compounds. Much higher levels of volatile alcohols were found in soy flour amended bread dough than in soy flour homogenates alone.     

CHEMICAL COMPOSITION OF THE SEED OF SUNFLOWER HYBRIDS AND OPEN POLLINATED VARIETIES

SUMMARY— The seed of high oil hybrids and open pollinated sunflower varieties from experimental plantings at nine locations in six southern states in 1969 was analyzed for moisture, crude protein, total oil and fatty acid composition. Total oil content ranged from 28.8–44.7% with an average of 35.3% for hybrid varieties and 39.5% for open pollinated varieties. The crude protein ranged from 16.9–25.1%. All the introductions mere relatively low in palmitic and stearic acids. Small amounts of palmitoleic, linolenic, arachidic, behenic and lignoceric acids were present in all samples. Oleic acid ranged from 33.4–62.7% and linoleic acid from 27.3–54.2%. The average oleic and linoleic acid content of the open pollinated varieties at the nine locations was 46.6 and 41.6%, respectively, as compared to 49.4 and 39.6% for the hybrids. The linoleic acid content of sunflower oil varied inversely with temperature during development of the seed. The oil of the sunflowers grown at the warmer locations and at the lower latitudes had a lower linoleic acid content than of those grown at somewhat cooler locations and higher latitudes.     

EFFECT OF COLD STORAGE ON THE QUALITY CHARACTERISTICS OF ‘AU-RUBRUM’ PLUMS1

The effect of cold storage (0°C) and maturity on the physical, chemical and sensory characteristics of plums (cv. ‘AU-Rubrum’) was determined. The size, weight, soluble solids and total sugar contents of the more mature fruit were significantly higher (P<0.05) and the “L” and hue angle were significantly lower (P<0.05) than plums in the less mature class. ‘AU-Rubrum’ fruit contained glucose, fructose and sorbitol but had no sucrose. Artificially ripening fruit at 20°C had a significant effect (P<0.01) on all color values for both maturity 1 and 2 fruit. The titratable acidity and sugar contents of the fruit ripened at 20°C were lower for ripened than for unripened fruit. Storage of the plums at 0°C for 5 weeks followed by subsequent ripening at 20°C had no significant effect on physical, chemical or sensory characteristics. Data indicate that ‘A U-Rubrum’ plums which have one-half red ground color (maturity 1) will develop full color and complete the normal ripening process. Data also indicate that the plums can be stored for at least 5 weeks at O°C without loss of quality and that the cultivar has potential for shipping to distant markets.     

Na+ Binding as Measured by 23Na Nuclear Magnetic Resonance Spectroscopy Influences the Perception of Saltiness in Gum Solutions

Binding of Na⁺ in aqueous gum systems as determined by ²³Na nuclear magnetic resonance (NMR) spectroscopy and its relations to perceived saltiness were examined. Two levels of NaCl (0.1% and 0.2%) were added to two concentrations (0.1% and 0.3%) of two ionic (xanthan and kappa carrageenan) and two non-ionic (locust bean and guar) gum solutions. Saltiness perception was affected by the ionic properties of the gums. NMR transverse relaxation rates (R₂, see^?l) indicated Na⁺ was less mobile in ionic than nonionic systems. Ionic gums correspondingly suppressed saltiness perception- compared to nonionic gums. As Na⁺ increased in both ionic and nonionic systems, R₂ values converged and perceived saltiness equalized. Food components that bind Na⁺ may suppress saltiness perception, which may be important in low-sodium foods.     

OPTIMIZATION OF ALGIN/CALCIUM BINDER IN RESTRUCTURED BEEF

Optimal use of ingredients can affect both the functionality and economics of meat products. The effects of 0–0.8% sodium alginate (algin), 0–0.15% calcium carbonate, 0–1.2% encapsulated lactic acid, 0–0.18% dry lactic acid, 0–0.12% calcium lactate and 0–0.3% palm oil on raw and cooked bind, discoloration, flavor, mouthfeel, aroma, cook yield and pH of restructured beef were studied. A formulation of 0.4% algin, 0.075% calcium carbonate and 0.6% lactate was optimal based on product characteristics and quantity of ingredients added. Inferior products resulted from the use of individual components of commercial lactate or the exclusion of calcium carbonate from the formulation.     

Effect of Initial Dissolved Oxygen Levels on the Degradation of Ascorbic Acid and the Browning of Lemon Juice during Storage

The effect of different initial dissolved oxygen concentrations (0.41, 1.44, and 3.74 mg/L) on rate of deteriorative quality changes [ascorbic acid degradation, browning, hydroxymethylfurfural (HMF) and furfural production) in lemon juice stored at 36°C was investigated. No significant effects on rate of ascorbic acid degradation and furfural formation could be attributed to the different oxygen levels. Degradation of ascorbic acid appeared to be predominantly anaerobic. Lag period before browning increased depended on oxygen level. Zero-, first- and second-order kinetic models were fitted to various degradative reactions occurring in lemon juice during storage. Highly significant correlations were obtained between browning index, HMF, and furfural formation, suggesting that all three would be suitable as chemical indices of storage temperature abuse in lemon juices.     

CORRELATING EQUATIONS FOR THE RECOVERY FACTOR AND THE BLASIUS FUNCTIONS FOR FLOW ALONG A FLAT PLATE

This paper describes the development of a complete set of continuous, comprehensive correlating equations for the recovery factor, and for the various functions of the velocity field which are required for calculation of heat transfer in the laminar boundary layer regime. These expressions are based on theoretical asymptotes and intermediate numerical values. Asymptotes were derived in the few instances for which they were not already known. Additional numerical values were computed to support the construction of the correlating equation for the recovery factor, but prior computed values were sufficient for the velocity functions.     

Light-emitting diode flashlights as effective and inexpensive light sources for fluorescence microscopy

Since the development of X-ray computed tomography as a medical diagnostic tool, it was adapted and extended for many scientific applications, including plant structure research. As for many biological studies, sample preparation is of major importance to obtain good-quality images. Therefore, we present a new preparation method for fresh material which includes critical point drying and heavy metal staining. This technique enhances the contrast of fresh tissues, prevents artefacts such as tissue compression, and requires no embedding.