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Both fresh and frozen asparagus rapidly deteriorate in quality due, in part, to the formation of oxidative off-flavors. Anti-oxidants and chelating agents prevent lipid oxidation in vegetables, but increasing the levels of such compounds in whole vegetables is difficult. Vacuum infusion was optimized to saturate asparagus spears with ascorbic acid without damaging tissues. The combination of vacuum infusion of ascorbic acid and thermal blanching effectively prevented the formation of oxidative off-flavors and hexanal during frozen storage. Sensory evaluations correlated with hexanal levels following frozen storage.
Callus of Rosmarinus officinalis L. 'Lockwood de forest' was induced from stem segments (3 mm long) using different concentrations of thidiazuron (TDZ). The original stem segments used as explants were found to have a higher level of linalool than was found for leaf segments. Linalool is one of the monoterpenes identified in rosemary plants and it has a pleasant aroma. TDZ has a significant effect on callus formation and callus texture. The callus formed was light green to yellow and/or had some meristimatic dark green cells. TDZ had a significant linear effect on the callus fresh weight. The meristimatic green cells formed on all calli except those proliferated on the lowest concentration of TDZ (0.5 mg/l). No callus was induced from stem segments cultured on TDZ-free medium. The fresh calli from other treatments were soaked in hexane as a solvent for monoterpene analysis using GC/MS. No monoterpenes could be detected in the callus induced on the medium containing the lowest concentration of TDZ. Comparing to the stem segments taken from the parent plants only 4 of 10 monoterpenes identified were found in the callus: α-pinene, β-pinene, 1,8-cineole, and camphor.
Shoot tips (7 to 10 mm long) of rosemary plant (Rosmarinus officinalis L. 'Lockwood de forest') were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of thidiazuron (TDZ) (0, 0.5, 1.0, 1.5, and 2 mg/l) alone or with 3-indole acetic acid (IAA) at 0.5 mg/l. The effect of TDZ and IAA on the proliferation of rosemary shoot tips has been reported in a previous meeting. Here, we report on the effect of TDZ and IAA on the monoterpene constituents identified in the oil of rosemary plants propagated in vitro. The proliferated explants were soaked in hexane as a solvent, then the extractions were used for monoterpene analysis using GC/MS. A significant interaction of TDZ by IAA was found on most of the oil components identified. The highest levels of 1,8-cineole and borneol were obtained at 0.5 mg TDZ/l alone, while the highest level of camphor was obtained at 0.5 mg TDZ/l plus 0.5 mg IAA/l. The highest level of bornyl acetate was at 2 mg TDZ/l.
Fourteen asparagus cultivars were established in 1988 in eastern Nebraska on a heavy silty clay soil to determine suitability for Nebraska production. Total & marketable yields differed among cultivars with highest total & marketable yields obtained with “UC157-F1”, “Jersey General”, “Jersey Knight”, 44P×22-8, 51×22-8 & Md10×22-8. Production of the cultivars “Jersey Gem”, “Jersey Giant”, & “Jersey General” was additionally compared as green & blanched (white) production under white-on-black plastic blanching frames. Lowest ratio of culls to marketable spears & highest marketable weight was obtained with “Jersey General” for both blanched & green spears. Although total weight was greater for green asparagus, use of blanching frames reduced the number of culls for each cultivar and increased the weight of marketable spears to exceed that of green asparagus.
Previous research on leaf lettuce has shown that altering the N:S ratio has an effect on plant color and N and S content. It appears that nitrogen rates can be decreased if known rates of sulfur are applied. The next step was to determine what effect altering the N:S ratio in lettuce had on consumer acceptance of the product.
`Grand Rapids' lettuce was grown hydroponically at six rates of S (0, 7.5, 15, 30, 60, 120 ppm) and four rates of N (30, 60, 120, 240 ppm). Sensory evaluation was performed on 20 of 24 treatments. The sensory panel was composed of 12 panelists who used the nonstructured hedonic scale to evaluate each lettuce treatment on appearance, color, texture, flavor, bitter flavor, and overall acceptability.
Results from the sensory evaluation indicate that differences in color, appearance, and bitter flavor were detected between treatments by the panel. Lettuce plants that received higher amounts of N in relation to S were considered less bitter in flavor and, over all, more acceptable than plants which received higher amounts of S in relation to N. These results indicate that altering the N:S ratio will affect consumer acceptance of leaf lettuce.
Rosemary (Rosmarinus officinalis) belongs to the Lamiaceae family, and is native to the Mediterranean and one of the most important medicinal herbs containing antioxidants in its leaves. One of the most important antioxidants is rosmarinic acid (RA). The aim of this study was to test the concentration of (RA) and chlorophyll content in leaves and callus of five successive subcultures of five different genotypes of rosemary. They were: 1) `Majorca'; 2) Rosmarinusofficinalis; 3) `Pine Scented'; 4) `Madeline Hill', and 5) APR. It was found that the highest concentration of RA in leaves was in `Pine Scented', while the lowest concentration was for APR and `Madeline Hill'. However, in the callus the highest RA concentration was for Rosmarinusofficinalis in the second subculture and `Madeline Hill' in the third subculture, while the lowest RA concentration was for `Majorca', `Pine Scented', and APR. The RA concentration in callus declined after the second and the third subculture for Rosmarinusofficinalis and `Madeline Hill', respectively. We concluded that it is preferred to use `Pine Scented' for RA extraction from the leaves while for RA extraction from callus it is better to use Rosmarinusofficinalis in the second subculture or `Madeline Hill' in the third subculture.
There is little information regarding processing methods that result in quality and uniformity in varietal apple wines. The object of this research was to determine if apple cultivars grown in the Great Plains region could be used to produce premium quality single cultivar wines, and to establish efficient processing methods that optimize quality. The qualities of single cultivar apple (Malus ×domestica) wines were investigated, including chemical characteristics of the apple juices, e.g. total soluble solids, acidities, and tannin contents. Analyses were performed on the fresh juices, fermenting juices, wines held for 6 months, and the aged wines. Fermentable sugar content was increased either by the addition of sucrose or by the addition of concentrated juice of the same apple cultivar. An optimized method of purge and cold trapping injection capillary gas chromatography was applied to the analysis of some volatile constituents. Profiles of the wine volatiles were analyzed to determine differences among cultivars. The harsh flavors and yeasty odors of the wines diminished after 6 months of storage. Acidity and volatile acidity increased slightly during storage. Tannin contents, fermentation efficiencies and volatile profiles differed among varieties. This research indicated that some apple cultivars grown in the Great Plains produce acceptable single cultivar wines.
Rosemary Rosmarinus officinalis is a member of the Lamiaceae. Rosmarinic acid (RA) is a very strong antioxidant produced in the chloroplast, and used to protect plant tissues against oxidative stress. A number of investigations showed that the sucrose concentration in the callus growing medium greatly influenced the production of secondary metabolites of the phenylpropanoid pathway such as RA. The aim of this study was to test the effect of elevated sucrose concentrations (2%, 3%, 4%, 5%, and 6% sucrose) and the effect of light and dark treatments on the production of RA in the callus of five different genotypes. The genotypes were Majorca, Rosmarinus officinalis, Pine Scented, Madeline Hill, and APR. It was found that the dark treatment produces more RA than the light treatment in all genotypes, and in all sucrose concentrations. The RA concentration increased with increasing the sucrose concentration from 2%—reaching the highest concentration at 4% and 5% in most genotypes. The RA concentration declined again at 6% sucrose in all genotypes. We concluded that for the extraction of RA from rosemary callus it is preferred to be produced in the dark—this will save energy and will produce more RA than the light treatment. Also it is preferred to use sucrose concentration at 4% for genotypes Rosmarinus officinalis, Pine Scented, and APR; and 3% sucrose for genotype Madeline Hill in the dark condition. While for the light condition, it is preferred to use 5% sucrose with genotypes Majorca, Rosmarinus officinalis, Pine Scented, and Madeline Hill; and 4% sucrose for genotype APR.
Phenolic levels have been analyzed in several grape cultivars that are suited for growing in southeastern Nebraska. The phenolic levels of these cultivars are not known to have been previously published. The polyphenol content of fruits and fruit products such as wine have been shown to be directly correlated to the antioxidant potential of the product. Antioxidants help to prevent the effects of aging and age-associated diseases. The grape cultivars in the study are grown primarily for wine production, but also as fresh table grapes and for making juice and jellies. The total phenolic content is being analyzed by the Folin-Ciocalteu method. Of the red grapes, `St. Croix' and `Frontenac' have the highest levels of polyphenols, followed by `Chambourcin' and `deChaunac', with levels varying from 1.4–4.9 mg·g-1 (polyphenols/grape), measured as gallic acid equivalents (GAE). The white grapes `Vignoles' and `LaCrosse' have total phenolic levels of 1.4 to 2.2 mg·g-1 (polyphenols/grape), also measured as gallic acid equivalents (GAE).