Wheat moisture effects

W. R. Windham, C. S. Gaines, R. G. Leffler. Effect of wheat moisture content on hardness scores determined by near-infrared reflectance and on hardness score standardization. Cereal Chem 70 662-666, 1993. 

J. K. Martin, Effect of soil moisture on the release of organic carbon from wheat roots. Soil Biology and Biochemistry 9 303 (1977). 

No deleterious effects of either the wheat mulch or tillage were observed on soybeans (Table V) or corn (data not presented). In general, crop growth was better in mulched or no-till plots. Enhanced soil moisture in the mulched treatments and reduced morningglory densities in the non-tilled treatments may have contributed to improved crop growth. 

On the other hand, allelopathic effect was negatively influenced by rainfall (Shiming 2005). The inhibition process was mitigated by shading and consequent moisture conservation (Muller 1966). Allelopathic activity can vary as well with photoperiod (Peng et al. 2004). Harder et al. (1998) found out that an increasing availability of nutrients decreased the concentration of allelopathic effective phenolic compounds in the plants of two winter wheat varieties. In soil, allelochemicals can be adsorbed by soil particles, decomposed by microorganisms and move with water. 

Temperature and moisture are two of the most important environmental variables that affect microbial growth, survival, and activity. At optimal temperature and moisture conditions, chemical and enzymatic reactions in the cell will occur the most rapidly and growth and activity will be the highest. However, below and above these optimal conditions, microbial activity decreases. The microbial degradation of. v-triazines appears to follow the same pattern. The effect of soil moisture and temperature on the degradation of terbutryn was evaluated by Chu-Huang et al. (1975). They reported that after 20 weeks of incubation above 10°C and at 14% soil moisture, phytotoxic levels of terbutryn to wheat were not detected in Teller sandy loam soil. 

The experimental data presented herein are the result of exploratory research aimed at bracketing the necessary moisture and inoculum loads for effective pilot-scale distributed upgrading of wheat straw stems for production of straw-thermoplastic composites (4,15). An exploratory approach was chosen for these tests because full-scale outdoor systems having few environmental controls would be difficult if not impossible to closely control. Both temperature and moisture levels vary owing to variations in heat,... 

Figure 8.16 Effect of moisture content on retrogradation kinetics of starch in starch gels or bread 1 wheat starch gels stored at 4°C for 14 days 175 2, 3 and 4 correspond to wheat starch gels, bread and bread with 0.5% monoglyceride, respectively, stored at 25°C for seven days.178...

Moreover, the bread crumb s moisture loss during seven days of storage open to the air, also did not show a consistent dramatic effect on these two tensile parameters (Chen et al. 1994) as one would expect. The same can be said about the compression parameters, which too showed little correlation with the moisture loss, which was measurable, of course. These reported findings, if indeed representative of the three tested breads (white, Canadian and whole wheat), would suggest that the initial textural changes that accompany bread staling are quite subtle and hence cannot be always manifested in the described crude mechanical parameters. An alternative explanation is that the failure to find the expected trends was mainly due to the large scatter in the experimental results that masked the true trend, if it really existed. 

Effects of Extrusion on Starch. Processing starch by extrusion results in molecular fragmentation. The effects on the MWDs of flours from wheat and corn starch were determined (18-20). Starch flours varied in amylose, amylopectin, and protein content. Samples were subjected to twin-screw extrusion with varying moisture content, screw speed, die temperature, mass flow rate, and protein content. Starch flours were directly dissolved in the solvent DMAC-LiCl without prior iso-... 

The presence of hollows in cooked rice grains was additionally confirmed for four more cultivars Koshihikari with various amylose contents."" The size, shape and total volume of hollows differed between cultivars. The hypothetical model for the formation of hollows has not been proved experimentally. NMR microimaging was used to determine moisture distribution in boiled Japanese noodles (udon) made from different varieties of wheat.The T2 profile of a piece of boiled udon was monitored in time course measurements during and after boiling. Water permeation from the surface to the core was evaluated by the T2 profile. Effect of moisture distribution on texture of boiled Japanese noodles was discussed. 

An automated NIRS system capable of scanning individual grains containing late-instar larvae of S. oryzae, R. dominica, or S. cerealella at the rate of 15 kernels/min has been developed in the United Kingdom (Chambers et al., 1998). The system was effective and could detect the infestation irrespective of the type/class of wheat, its protein content (range 11.32 16.2%) and moisture content (range 10.0 13.2%). The minimum detectable size of the insects by NIRS varied between species. As identified by x-ray analysis, the NIRS system has been shown to detect R. dominica as small as 1.1 mm2 with 95% level confidence, whereas for S. oryzae it was 2.0 mm2, and for S. cerealella 2.7 mm2. For a particular insect species, the accuracy of detection increases as insect development proceeds. Accordingly, in S. oryzae the accuracy of detection of first instar larvae was 10%, second instar larvae 24%, third instar larvae 82%, fourth instar larvae 95%, and the accuracy was 100% for pupae and adults. 

Lewandowicz et al. (1997) conducted experiments to study the effect of microwave processing on the physicochemical properties of cereal starches. They used corn, wheat, and waxy corn at an intermediate moisture content of 30%. Brabender rheological method, light microscopy, x-ray diffractometry (XRD), and differential scanning calorimetry (DSC) methods were used to test different properties of starches, both before and after microwave processing. The experimental results are shown in Figures 3.2 and 3.3. Corn and wheat had pronounced changes in their molecular structure compared to waxy corn. 

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