Kathleen Warner

Light Quality During Early Seedling Development Influences the Morphology and Bitter Taste Intensity of Mature Lettuce. (Lactuca sativa) Leaves

Summary The genetic constitution of a vegetable crop species such as lettuce. ( Lactuca sativa ) is an important determinant of characteristics such as leaf size, shape, texture, color, and taste. Whereas introduction of improved traits by breeding or genetic engineering is possible, an alternative approach involves modification of the mature phenotype by manipulation of the early growth environment. To explore this phenomenon, lettuce was grown under specific light quality treatments. (red, red + far-red, blue, and white light), both continuously and with color switching at various intervals. Leaves grown in continuous light quality showed characteristic differences in leaf area, shape, dry weight, and bitter taste intensity as determined by an analytical sensory panel. However, red light supplied for the first 7 d of growth conditioned weak bitterness intensity whether or not plants were switched to white light for 18 or 26 d. Leaf area and dry weight were determined by the first 7 d in red or blue light whether or not plants were switched to the opposite color light for 9 or 35 d. These observations demonstrate that persistent photomorphogenic switching of leaf development can take place before leaf emergence, and that light quality signals received in the early growth environment can have a latent effect on subsequent plant development.

Composition of oils extracted from potato chips by supercritical fluid extraction

To determine effects of two extraction procedures on oil compositions, tocopherols, monoacylglycerol, diacylglycerol, triacylglycerol, free fatty acids, polymers and polar components were determined in oils after extraction from potato chips by either supercritical carbon dioxide or hexane. Potato chips were fried in cottonseed oil or low linolenic acid soybean oil and sampled after 1, 10 and 20 h of oil use. Both extraction methods recovered comparable amounts of oil from the potato chips. Compositions of triacylglycerol and non-triacylglycerol components including tocopherols, monomer, polymer, monoacylglycerol, diacylglycerol were similar for samples of chips fried in either oil except for the δ-tocopherol data for potato chips fried in the low linolenic acid soybean oil used for 10 h of frying. There were some differences between the composition of low linolenic acid soybean oil extracted from the potato chips compared to the fryer oil at the 20 h sampling time. These results showed that the supercritical carbon dioxide extraction gave similar results to hexane extraction in yield and composition of oils from potato chips.

Growth, feed conversion, protein utilization, and sensory evaluation of Nile tilapia fed diets containing corn gluten meal, full-fat soy, and synthetic amino acids

Abstract Experimental diets containing 36% protein, corn gluten meal, full-fat soy meal, and high-lysine corn, as well as a commercial (control) diet were fed to tilapia with 9 g initial weight for 12 weeks in aquaria. Weight gain, feed conversion ratio, and protein efficiency ratio for experimental diets and control diet were not significantly different and ranged from 754-918%, 1.67-1.79, and 1.42-1.56, respectively. No advantage was gained when fish meal (4 or 8%) was incorporated into the experimental diets. Tilapia fed diets containing 3-4% fat performed equally well compared with fish fed diets with 7-8% fat. A trained 10-member sensory panel evaluated the flavor characteristics of harvested, cooked tilapia fillets. The intensities of flavor characteristics of cooked fillets from tilapia raised on pellets containing 23 and 34% corn gluten meal were not significantly different from fish fed commercial fish feed without corn gluten meal.