Changes in fructose, sucrose, and glucose were investigated in cured roots of `Beauregard', `Jewel' and `Travis' sweet potatoes stored at 15°C and 1.5°C for 8 wk. Samples of 6 roots each in triplicate were analyzed at 2 wk intervals. At each interval, samples were also heated for 5, 10, 20 or 40 min. at 100°C to determine changes in rate of maltose conversion. Roots stored at 15°C displayed gradual or no increase in sugars over the 8 wk. Roots stored at 1.5°C increased more rapidly in sugars, especially fructose, over the same time. `Jewel' had the greatest increase in the sugars when stored at 1.5°C. There was no consistent pattern of maltose conversion in roots stored at 15°C over the 8 wk storage time. Roots stored at 1.5°C displayed a reduction in ability to convert starch to maltose upon heating. Less maltose was produced with increasing time of storag at 1.5°C. `Beauregard' and `Jewel' changed the most, while `Travis' changed only slightly.
Paul W. Wilson, David H. Picha, and John M. Aselage
Edward W. Bush, Paul Wilson, Dennis P. Shepard, and Gloria McClure
Priming or presoaking seed of common carpetgrass (Axonopus affinis Chase) and centipedegrass [Eremochloa ophiuroides Munro. (Kunz)] increased germination percentage and decreased mean time of germination (MTG) at 20, 25, and 30 °C. The effect of presoaking and priming was dependent on grass species and temperature. The optimum seed germination temperature for both of these warm-season species was 30 °C. Maximum effect on common carpetgrass or centipedegrass seeds was achieved by priming in 2% KNO3; higher concentrations did not improve germination percentage or MTG, and 4% was in some cases detrimental. Germination was higher and MTG lower at 20 and 30 °C than at 15 °C. Presoaking common carpetgrass and centipedegrass seeds was the most efficient seed enhancement treatment for germination at 30 °C.
Nolan Farace, Charles E. Johnson, Paul W. Wilson, and Witoon Prinvawiwatkul
Fruits from five mayhaw selections were harvested and frozen at –2 °C. Juice was extracted with a steamer and kept in storage at 5 °C until processing. Percent soluble solids, percent malic acid, initial pH, and color were then determined for postharvest characteristics. 550 mL juice was placed in a 2000-mL beaker and heated until boiling. Dry pectin mixed with a portion of the total sugar equivalent to 5–10 times the weight of the pectin was sprinkled into the boiling juice. Once pectin was in solution, the amount of sugar to obtain a ratio of ≈45 parts fruit: 55 parts sugar was added to the mixture. The mixture was cooked until the soluble solid reading reached 65% and then poured into jars to cool to room temperature. The five mayhaw jellies alone with one commercial apple and one commercial mayhaw were evaluated using a panel preference test. Evaluation was based on a scale from dislike extremely to like extremely. Preference scores indicated that mayhaw jellies were preferred to a commercially available apple jelly. There was a definite preference to deep red colored jellies. The specific varietal jellies were preferred to a commercially available mayhaw jelly.
Paul W. Wilson, Gloria B. McClure, and Julian C. Miller Hall
The demand for hot sauce products continues to expand in the U.S. In the case of jalapeno pepper sauce, there are many cultivars available for sauce production but those best suited for processing have not been adequately determined. Six cultivars (four replications) of jalapeno peppers (`Coyame', `Grande', `Jalapeno-M', `Mitla', `Tula' and `Veracruz') were evaluated for mash fermentation. The attributes studied during mash aging were color spectra, capsaicin content and fermentable sugars. Fructose and glucose were the predominant sugars in jalapeno peppers and these sugars were utilized gradually with time indicating slow fermentation by microorganisms in the 15% salt mash. Capsaicin and dihydrocapsaicin were the predominant capsaicinoids in the jalapeno peppers with `Tula' containing the greatest concentration and `Veracruz' the least. All mashes displayed an apparent and unexpected rise in measurable capsaicinoids up to 6 months with a decline at 12 months. Color changes in the pepper mash were rapid initially but slowed after the first month of fermentation. Percent reflectance in fresh ground peppers was strongest in the range of 550–560 nm but, after salting, reflectance shifted to 580–590 nm and remained throughout the fermentation. Based on the characteristics tested, any of these cultivars would make a suitable mash for sauce. The heat content of the final product could be controlled by cultivar selection or through blending.
Foong M. Koh, Gloria B. McClure, and Paul W. Wilson
In Summer 2003, sorbic acid was detected in a processed Louisiana product that had been shipped internationally. This discovery caused the food product to be rejected by the foreign market since sorbic acid was not declared on the label. The source was eventually traced by an analytical lab to a garlic powder component used in the product. Subsequent evaluations by the lab of fresh and dried garlic products obtained from stores indicated sorbic acid. The presence of sorbic acid suggested that it might either be a contaminant or a previously unreported naturally occurring component of garlic. To determine which was more likely, 12 garlic varieties were planted in Baton Rouge, La., during September 2003 and harvested the following spring. In addition to this harvested garlic, fresh garlic, garlic juice and garlic powder were purchased in May 2004 from three local stores. All these samples plus the original product were analyzed for sorbic acid using spectrophotometry and HPLC methods at the LSU Horticulture Dept. None of the samples contained measurable quantities of sorbic acid except for the original product. Since there appears to be no naturally occurring sorbic acid in garlic, it is likely that at least a portion of the fresh and processed garlic distributed in the U.S. during 2003 may have been adulterated with sorbic acid.
Edward W. Bush, Ann L. Gray, Paul W. Wilson, and Robert I. Edling
Irrigation management is essential in producing quality woody ornamentals and minimizing off-site runoff. The closed-capture effluent device provided an inexpensive method of monitoring effluent in large containers throughout the year with minimal effort. Daily irrigation requirements for `Little Gem' southern magnolia (Magnolia grandifolia) were established throughout an entire growing season. The maximum daily water requirement was approximately 3 gal (11.4 L).
Edward W. Bush, Ann L. Gray, Paul W. Wilson, and Allen D. Owings
A closed capture irrigation apparatus was designed and constructed for the purpose of monitoring irrigation effluent volume and nutrient analysis from 121-L redwood tree boxes. Measurements were taken monthly from Apr. 1997 to Oct. 1998. Tree boxes were filled with either a 3 pine bark: 1 sand: 1 peat or 3 pine bark: 1 soil media and planted with `Little Gem' magnolia [Magnolia grandiflora (L.) `Little Gem'] or Southern live oak (Quercus virginiana var. virginiana Mill.). In-line, pressure-compensated drip emitters provided irrigation water at the rate of 2 L/h. Daily irrigation volume ranged from 8 L in the fall and spring to 16 L during the summer months. The collection apparatus was constructed from 1-cm angle iron, neoprene rubber, a small drain assembly, and a 22-L plastic container. A square metal frame (43 × 43 cm) was supported by 31-cm legs and draped by a neoprene rubber mat with a drain assembly installed in the center. The drain was positioned into the plastic container creating a closed system to reduce effluent evaporation. The container capacity was adequate to store at least 24 h of collected effluent. This apparatus proved to be an efficient method of collecting irrigation effluent from large containers.