Short Communication Effect of fruit ripeness and method of fruit drying on the extractability of avocado oil with hexane and supercritical carbon dioxide

Background: Oil yield from avocado fruit may be influenced by fruit pre-treatment and extraction method. Unripe and ripe avocado fruit pieces were deep-frozen at −20 ◦C and either freeze-dried or oven-dried (80 ◦C). Oil yield from these samples was determined after extraction with hexane and supercritical carbon dioxide (SC-CO2). The fruit samples were examined using scanning electron microscopy before and after oil extraction. RESULTS: Average oil yield from ripe fruit (freeze-dried and oven-dried combined) was 72 g kg−1 higher than from unripe fruit for SC-CO2 extracts and 61 g kg−1 higher for hexane extracts. This may be due to enzymatic degradation of parenchyma cell walls during ripening, thus making the oil more available for extraction. Freezedried samples had a mean oil yield 55 g kg−1 greater than oven-dried samples for SC-CO2 extracts and 31 g kg−1 higher for hexane extracts. However, oil yields from ripe fruit (freeze-dried and oven-dried) subjected to hexane extraction were not significantly different. All hexane extracts combined had a mean oil yield 93 g kg−1 higher than SC-CO2 extracts. CONCLUSION: SC-CO2 may be more selective and may create paths of least resistance through the plant material. Hexane, on the other hand, is less selective and permeates the whole plant material, leading to more complete extraction and higher oil yields under the experimental conditions

Effect of bambara groundnut supplementation on the physicochemical properties of rice flour and crackers

This study evaluated the effect of bambara groundnut supplementation on the physicochemical properties of local rice flour and baked crackers. Bulk and true density, porosity, water absorption index, oil absorption capacity, pasting properties by RVA, morphological appearance by SEM, color by calorimetry, and textural properties by TA.XT2 analysis of wheat and two formulations of rice-legume flours and crackers were studied. Moisture (10.94%) and carbohydrate (77.42%) levels were significantly greater in wheat flour than the rice-legume flours, while the reverse was true for fat and ash. Also rice-legume flours had significantly greater water and oil absorption capacity and lower water solubility compared to wheat flour. Compared to wheat crackers, rice-legume crackers had greater fat and ash, 20.51 and 3.57%, respectively, while moisture was significantly lower in the rice-legume crackers by 41 to 58%. Rice legume crackers were significantly harder and had significantly increased spread ratio. The results obtained from the development of locally grown rice and underutilized legume bambara groundnut showed great promise in physicochemical and functional properties and may be a good replacement for wheat flour to serve as a gluten-free product

Sorghum Transformation: Overview and Utility

Over the past decade genomics resources available for sorghum have rapidly expanded (Paterson Int J Plant Genomics 2008:6, 2008), these resources, coupled with the recent completion of the genome sequence which is relatively small in size (730 Mb) (Paterson et al. Nature 457:551–556, 2009) makes sorghum a rather attractive species to study. Moreover, the USDA germplasm system maintains 42,614 accessions, of which more than 800 exotic landraces have been converted to day length-insensitive lines to facilitate their use in breeding programs. In addition, a set of EMS mutation stocks developed by the USDA Plant Stress and Germplasm Development Unit in Lubbock, TX (Xin et al. Bioenerg Res 2:10–16, 2009) will be a valuable resource for functional genomics studies in sorghum. However, in order to be a robust system for study a suite of functional genomics tools are necessary to complement these other resources to aid in down-stream hypothesis testing. A key functional genomics tool is the ability to modulate gene expression through the introduction of transgenic genetic elements. This is exemplified by recent work (Cook et al. Plant Cell 22:867–887, 2010) in which RNAi experiments were employed to specifically reduced expression of two alkylresorcinol synthases to demonstrate their role in the synthesis of the allelopathic molecule sorgoleone. In addition to its value as a functional genomics tool, plant transformation offers a route to broaden access to novel input and output traits for sorghum breeding programs