Studies on the Rapid Methods for Evaluating Seed Vigor of sweet Corn
Since the germination test is still the main method for evaluating seed vigor of sweet corn, it is necessary to study the rapid methods for evaluating their vigor. First, two vigor levels of 9 super sweet corn and 9 sugar enhanced corn hybrids were distinguished by accelerated ageing treatment. Next, their vigor statuses were tested by rapid methods such as electrical conductivity (EC), soluble sugar (SS), volatile aldehyde (VA), dehydrogenase activity (DA) and Q2 oxygen sensing technology. Correlation relationship was analyzed between the above tested values and vigor performances. The results showed that EC, SS, VA, DA, oxygen metabolism rate (OMR), critical oxygen pressure (COP) were all suitable to evaluate seed vigor of sweet corn. Furthermore, VA was optimal for evaluating seed vigor of super sweet corn. DA was optimal for evaluating sugar enhanced corn.
Study on Physiological Characteristics and Seed Activity Changes of Two Maize Inbreds in Ageing Course
Seeds of two maize inbreds(Mo17, 478)were used to investigate the physiological characteristics and germination activity changes in their artificial ageing course. The results showed: after treated with hot water of 58℃±1℃, the germination index and activity index of the seeds decreased as the treating time extension; but the conductance rate and MDA content increased. The correlations between conductance rate, MDA content and the germination index, activity index were negative and that between dehydrogenase, amylase and all germination indexs were positive. Three bands (Rf=0.44? 0.77? 0.80) of esterase in Mo17 seed disappeared after aging 30 minutes and two bands (Rf=0.72? 0.78) in 478 seed disappeared after aging 25 minutes.
Development of new analytical methods for the determination of caffeine content in aqueous solution of green coffee beans
BackgroundThis study was conducted to develop fast and cost effective methods for the determination of caffeine in green coffee beans. In the present work direct determination of caffeine in aqueous solution of green coffee bean was performed using FT-IR-ATR and fluorescence spectrophotometry. Caffeine was also directly determined in dimethylformamide solution using NIR spectroscopy with univariate calibration technique.ResultsThe percentage of caffeine for the same sample of green coffee beans was determined using the three newly developed methods. The caffeine content of the green coffee beans was found to be 1.52 ± 0.09 (% w/w) using FT-IR-ATR, 1.50 ± 0.14 (% w/w) using NIR and 1.50 ± 0.05 (% w/w) using fluorescence spectroscopy. The means of the three methods were compared by applying one way analysis of variance and at p = 0.05 significance level the means were not significantly different. The percentage of caffeine in the same sample of green coffee bean was also determined by using the literature reported UV/Vis spectrophotometric method for comparison and found to be 1.40 ± 0.02 (% w/w).ConclusionNew simple, rapid and inexpensive methods were developed for direct determination of caffeine content in aqueous solution of green coffee beans using FT-IR-ATR and fluorescence spectrophotometries. NIR spectrophotometry can also be used as alternative choice of caffeine determination using reduced amount of organic solvent (dimethylformamide) and univariate calibration technique. These analytical methods may therefore, be recommended for the rapid, simple, safe and cost effective determination of caffeine in green coffee beans.