Two chemical methods which are commonly used for rice grain freshness determination were investigated for their efficiencies. Method 1 is made of bromothymol blue indicator, and the principle is based on indicator＇s ...Two chemical methods which are commonly used for rice grain freshness determination were investigated for their efficiencies. Method 1 is made of bromothymol blue indicator, and the principle is based on indicator＇s color which is changed in according to pH of the stored rice grains. Method 2 is based on peroxidase activity which deteriorates during storage of rice grains. Both methods were used for determination of fresh-aged rice index of six Thai-rice cultivars, four from non-waxy rice cultivars （KDML 105, Chai Nat 1, Chai Nat 2 and Phitsanulok 2） and two from waxy rice cultivars （San-pah-tawng and RD6）. Rice samples were kept in the forms of paddy and polished rice. Fresh-aged rice indices were determined using both methods every two weeks over the storage period of 24 weeks （six months）. It was found that both methods were capable of detecting fresh-aged rice indices. The color of chemical solutions changed with regards to the age of rice grains and it could be detected spectrophotometrically. Rice grains which have been kept as paddy provided more consistent results. Method 1 is recommended for industrial application as it is simple, efficient and inexpensive.展开更多
[ Objective] The content of total antimony （Sb） in fresh fruit was investigated and its pollution was evaluated, to provide the basic data for diet exposure evaluation. [ Method] The content of total Sb in 194 sampl...[ Objective] The content of total antimony （Sb） in fresh fruit was investigated and its pollution was evaluated, to provide the basic data for diet exposure evaluation. [ Method] The content of total Sb in 194 samples was detected by hydride generation-atomic fluorescence spectrometry （HG-AFS）, and the Sb pollution in several fruits was evaluated by the method of single factor pollution index. [ Result ] The mean of total Sb was 0. 005 6 mg/kg, and the median was 0.003 8 mg/kg. The minimum value was not detected while the maximum value was O. 21 mg/kg, and the confidence interval was ND-O. 019 mg/kg （PS-P95）. The medi- ans of total Sb content in different fruits successively were dragon fruit （0.011 0 mg/kg） 〉 kiwi fruit （0.008 0 mg/kg） 〉 peach （0.006 0 mg/kg）. According to the method of single factor pollution index, the index from all samples was less than 0.2, suggesting that the samples involved were under the normal background value. [ Conclusion ] The Sb was detected in all samples but under the background value, and it was concluded that there was no Sb pollution in fresh fruit in Hunan Province.展开更多
基金financially supported by the Thailand Research Fund(TRF)(Grant No.MRG-WI535S078)
文摘Two chemical methods which are commonly used for rice grain freshness determination were investigated for their efficiencies. Method 1 is made of bromothymol blue indicator, and the principle is based on indicator＇s color which is changed in according to pH of the stored rice grains. Method 2 is based on peroxidase activity which deteriorates during storage of rice grains. Both methods were used for determination of fresh-aged rice index of six Thai-rice cultivars, four from non-waxy rice cultivars （KDML 105, Chai Nat 1, Chai Nat 2 and Phitsanulok 2） and two from waxy rice cultivars （San-pah-tawng and RD6）. Rice samples were kept in the forms of paddy and polished rice. Fresh-aged rice indices were determined using both methods every two weeks over the storage period of 24 weeks （six months）. It was found that both methods were capable of detecting fresh-aged rice indices. The color of chemical solutions changed with regards to the age of rice grains and it could be detected spectrophotometrically. Rice grains which have been kept as paddy provided more consistent results. Method 1 is recommended for industrial application as it is simple, efficient and inexpensive.
基金Supported by Scientific Research Project of Medicine and Health Care in Hunan Province(B2014-162)Scientific Research Project of Xiangtan Science and Technology Bureau(SF20141003)
文摘[ Objective] The content of total antimony （Sb） in fresh fruit was investigated and its pollution was evaluated, to provide the basic data for diet exposure evaluation. [ Method] The content of total Sb in 194 samples was detected by hydride generation-atomic fluorescence spectrometry （HG-AFS）, and the Sb pollution in several fruits was evaluated by the method of single factor pollution index. [ Result ] The mean of total Sb was 0. 005 6 mg/kg, and the median was 0.003 8 mg/kg. The minimum value was not detected while the maximum value was O. 21 mg/kg, and the confidence interval was ND-O. 019 mg/kg （PS-P95）. The medi- ans of total Sb content in different fruits successively were dragon fruit （0.011 0 mg/kg） 〉 kiwi fruit （0.008 0 mg/kg） 〉 peach （0.006 0 mg/kg）. According to the method of single factor pollution index, the index from all samples was less than 0.2, suggesting that the samples involved were under the normal background value. [ Conclusion ] The Sb was detected in all samples but under the background value, and it was concluded that there was no Sb pollution in fresh fruit in Hunan Province.
