J.K. Collins

Lycopene from two food sources does not affect antioxidant or cholesterol status of middle-aged adults

BackgroundEpidemiological studies have reported associations between reduced cardiovascular disease and diets rich in tomato and/or lycopene. Intervention studies have shown that lycopene-containing foods may reduce cholesterol levels and lipid peroxidation, factors implicated in the initiation of cardiovascular disease. The objective of this study was to determine whether consumption of lycopene rich foods conferred cardiovascular protection to middle-aged adults as indicated by plasma lipid concentrations and measures of ex vivo antioxidants.MethodsTen healthy men and women consumed a low lycopene diet with no added lycopene (control treatment) or supplemented with watermelon or tomato juice each containing 20 mg lycopene. Subjects consumed each treatment for three weeks in a crossover design. Plasma, collected weekly was analyzed for total cholesterol, high density lipoprotein cholesterol (HDL-C) and triglyceride concentrations and for the antioxidant biomarkers of malondialdehyde formation products (MDA), plasma glutathione peroxidase (GPX) and ferric reducing ability of plasma (FRAP). Data were analyzed using Proc Mixed Procedure and associations between antioxidant and lipid measures were identified by Pearsons product moment correlation analysis.ResultsCompared to the control diet, the lycopene-containing foods did not affect plasma lipid concentrations or antioxidant biomarkers. Women had higher total cholesterol, HDL-C and triglyceride concentrations than did the men. Total cholesterol was positively correlated to MDA and FRAP while HDL-C was positively correlated to MDA and GPX. GPX was negatively correlated to triglyceride concentration.ConclusionsThe inclusion of watermelon or tomato juice containing 20 mg lycopene did not affect plasma lipid concentrations or antioxidant status of healthy subjects. However, plasma cholesterol levels impacted the results of MDA and FRAP antioxidant tests.

Effects of Deoxynivalenol on Content of Chloroplast Pigments in Barley Leaf Tissues

To understand further the role of deoxynivalenol (DON) in development of Fusarium head blight (FHB), we investigated effects of the toxin on uninfected barley tissues. Leaf segments, 1 to 1.2 cm long, partially stripped of epidermis were floated with exposed mesophyll in contact with DON solutions. In initial experiments with the leaf segments incubated in light, DON at 30 to 90 ppm turned portions of stripped tissues white after 48 to 96 h. The bleaching effect was greatly enhanced by addition of 1 to 10 mM Ca(2+), so that DON at 10 to 30 ppm turned virtually all stripped tissues white within 48 h. Content of chlorophylls a and b and of total carotenoid pigment was reduced. Loss of electrolytes and uptake of Evans blue indicated that DON had a toxic effect, damaging plasmalemmas in treated tissues before chloroplasts began to lose pigment. When incubated in the dark, leaf segments also lost electrolytes, indicating DON was toxic although the tissues remained green. Thus, loss of chlorophyll in light was due to photobleaching and was a secondary effect of DON, not required for toxicity. In contrast to bleaching effects, some DON treatments that were not toxic kept tissues green without bleaching or other signs of injury, indicating senescence was delayed compared with slow yellowing of untreated leaf segments. Cycloheximide, which like DON, inhibits protein synthesis, also bleached some tissues and delayed senescence of others. Thus, the effects of DON probably relate to its ability to inhibit protein synthesis. With respect to FHB, the results suggest DON may have multiple roles in host cells of infected head tissues, including delayed senescence in early stages of infection and contributing to bleaching and death of cells in later stages.

Lycopene Content Among Organically Produced Tomatoes

Abstract There is little information on how organic production methods affect phytonutrient content of tomato (Lycopersicon esculentum Mill.). This project was undertaken to determine how much lycopene was produced in tomatoes grown organically, and if tomatoes picked at the breaker stage could obtain full lycopene content. ‘Classica?, a Roma type of tomato, was highest in lycopene (106 mg·kg−1) and the other cultivars had 50–60 mg·kg−1 lycopene in soft red fruit. About 50% of the total lycopene found in soft red tomatoes was present in pink tomatoes and 70% in light red fruit. Fruit picked at unripe stages (breaker through light red) gained as much or more lycopene as those picked firm or soft red. Tomatoes grown organically contained substantial amounts of lycopene when ripened to firm red or soft red stages.

Consumer acceptability of low-sugar watermelon sweetened with non-calorie sweetener by a Native American community

Watermelons are a good source of lycopene, a carotenoid that exhibits antioxidant activity and may protect against some cancers. However, intake of watermelon may be restricted for individuals who have diabetes or those who limit carbohydrate intake. A low-sugar watermelon was developed at Lane, Oklahoma using traditional plant breeding techniques. The objective of this study was to determine whether the artificially sweetened low-sugar watermelon was acceptable with Native Americans, a group with a high incidence of diabetes. The red flesh from a low-sugar watermelon and a commercial variety of watermelon was removed and cut into cubes. Low and high levels of artificial sweetener were added to the low-sugar watermelon. Students at a Native American school (Grades 1–12) and adults at a Native American Feeding Center were asked to rate how much they liked or disliked the watermelon using a seven-point hedonic scale. Sugar composition, pH, lycopene and other carotenoids were analyzed from samples using established methods. The pH, lycopene, β-carotene and total carotenoid levels were similar among fruit. Artificially sweetened fruit were rated slightly more acceptable in taste than the commercial control watermelons by both age groups. The low-sugar watermelons were lower in sugar composition but were comparable with conventional melons in all other quality factors and were found acceptable in taste by a broad age group of Native American consumers.

Impact of cultivar and production practices on yield and phytonutrient content of organically grown watermelon

Abstract Cultural practices can affect quality and phytonutrient content of watermelon [Citrullus lanatus var. lanatus (Thunb.) Matsum. & Nakai]. Knowing which cultivars perform well under various production systems, and how these systems affect quality, yield, and phytonutrient content is imperative to ensure high quality and yield. There is limited information on how watermelon cultivars perform when grown with organic practices. Production characteristics of six watermelon cultivars from certified organic seed sources were compared under high (black plastic and mechanical cultivation for weed control) and low input (no-till) organic culture. The high input production method almost doubled the number of fruit produced for all cultivars; producing greater yields and heavier average fruit weights, but fruit had decreased quality (lower Brix and lycopene content) compared with the low-input production. ‘Triple Star’ was the most productive seedless cultivar in terms of number of fruit in both organic fields and had the highest marketable yield in the low-input field. ‘Early Moonbeam’ produced the largest number of fruit and the smallest fruit of the seeded cultivars. ‘Allsweet’, a seeded cultivar, had the highest marketable yield due to its larger size. ‘Triple Star’ had the highest quality (high lycopene and Brix content) in the low input field, but all triploid cultivars had similar quality aspects in the high input field. Among seeded cultivars, ‘Allsweet’ had the best quality at both locations; however, average lycopene content/fruit under low-input production was not significantly different when compared with ‘Sugar Baby’.