Peter N. Gichuhi

Nutritional, physical, and sensory evaluation of hydroponic carrots (Daucus carota L.) from different nutrient delivery systems.

Carrot (Daucus carota L.) has the highest carotenoid content among foods and is consumed in large quantities worldwide, while at the same time its market demand continues to increase. Carotenoids have also been associated with protective effects against cancer and other chronic diseases. The most predominant carotenoids in carrots are beta- and alpha-carotenes. Moisture, ash, fat, texture, color, carotene content, and consumer acceptance of carrots grown in a hydroponic system with nutrient film technique (NFT) and microporous tube membrane system (MTMS) were evaluated. The moisture contents of the NFT- and MTMS-grown carrots ranged from 86.8 +/- 0.13% to 92.2 +/- 2.25% and 80.9 +/- 0.31% to 91.6 +/- 1.01%, respectively. Fat and ash contents of the carrots were negligible. NFT-grown Oxheart had the most beta-carotene (9900 +/- 20 microg/100 g) while Juwaroot had the least (248 +/- 10 microg/100 g). However, the beta-carotene content of Juwaroot from the NFT batch II carrots was 3842 +/- 6 microg/100 g. MTMS-grown carrots had less variation in the total beta-carotene contents (2434 +/- 89 to 10488 +/- 8 microg/100 g) than those from NFT. Overall, Nantes Touchan (4.8 +/- 2.3) and Nevis-F (7 +/- 1.4) from NFT were the least and most preferred by consumers. Mignon was also acceptable to consumers, and significantly (P < 0.05) more preferred than the other carrots in that NFT batch. MTMS-grown Kinko and Paramex, which were significantly (P < 0.05) more preferred than Nandrin-F and the commercial field-grown carrot, were equally liked by consumers. Nevis-F, Mignon (NFT), Paramex, and Kinko (MTMS) are potentially good cultivars to be included in NASAs food system.

Nutritional and physical properties of organic Beauregard sweet potato [Ipomoea batatas (L.)] as influenced by broiler litter application rate

Organic farming has been on an upward trend in recent years. However, the manures used like broiler litter have variable nutrient content, making it important to establish optimal application rate, for maximum crop yield and quality. Additionally, some states like Alabama restricts the amount of broiler litter to control excessive nutrients accumulation which can lead to surface and ground water contamination. The current study evaluated the effect of broiler litter at rates 0, 0.5, 1, 2, and 3 t ha−1 (treatments T0, T0.5, T1, T2, and T3), on the nutritional and physical properties of Beauregard sweet potato. Analyses were performed to determine moisture, ash, fiber, vitamin C, and β-carotene contents using oven, muffler furnace, dye, and spectrophotometric methods; texture; and color using compressive strength and L, a, b system, respectively. Ash content of the samples ranged from 0.9% to 1.4% with a very strong positive linear correlation (r = 0.9) to the broiler litter rate. However, vitamin C had a quadratic relationship with the broiler litter rate with a peaking at T0.5 (15.5 mg/100 g). The yellow color (b-value) also had a strong linear relationship with the broiler litter rate (r = 0.86). However, the other measures showed moderate, weak, or negligible correlations to the broiler litter level. T0.5 had the highest β-carotene (262.0 μg/g), dry matter contents and had the most firm (0.040 kN) sweet potatoes with the deepest orange color (L = 60.7). Based on the studys findings, 0.5 t ha−1 appeared to be appropriate level of broiler litter, which is consistent with Alabamas law and is also advantageous in terms of low cost of farming practices and water pollution reduction.