The effects of gamma irradiation at different dose-rate on the anti-nutritional compounds (phytic acid, anti-trypsin), isoflavones and color of soybean (Glycine max L.).

Abstract

Research on the influence of gamma irradiation at different dose-rate on the anti-nutrient compound (phytic acid, anti-trypsin), isoflavones and color of soybean (Glycine max L.) has been done. The application of irradiation techniques on food products are frequently focused on the influence of radiation dose and the change of nutrient and anti-nutrient compounds as well as the quality of products. Gamma irradiation influence on the same dose, but with a variety of dose rates, especially on anti-nutrient compounds, isoflavone and color on soybean, has not been done. The change of anti-nutrient compound, isoflavone and color on soybean caused by irradiation were studied on a variety of dose-rate combinations (kGy/h) and different irradiation time (h). The purpose of this research was to study the effects of combination treatment between dose-rate (kGy/h) and irradiation time (h) or duration on the effectiveness of irradiated soybean, especially on the changes of its anti-nutrient compound, isoflavones and color. Radiation process parameter; (dose-rate and time in combination) for a control with the purpose to prove that irradiation on the same certain dose would have resulted different product quality if it had been done with different dose-rates and time. Furthermore, combination treatment between irradiation at higher dose-rate and shorter time could degrade anti-nutrient compound and resulted more minimum influence to the damage of brightness quality (color) than irradiation in lower dose-rate and longer time. This research was primarily focused on 3 (three) activities. The first step was to study the effect of gamma irradiation (60Co) at different dose-rate on the anti-nutrient compound (phytic acid and antitrypsin) and color on soybean. The second step of the research was to study the effects of gamma irradiation at different combination of dose-rate and time of exposure on the isoflavones contents of soybean. The third step of the research was a verification of the first and the second steps, namely: to study the effect of gamma irradiation on the low and high dose at different combination of dose-rate and time on phytic acid and color of soybean. In the previous research, the characterization of gamma radiation source capacity to determine dose map and dose-rate on irradiation area has been done. There were 4 (four) dose-rate locations which has been identified in the irradiation area; each of them was 1.30; 3.17; 5.71 and 8.82 kGy/h. The rasio of maximum and minimum dose (Dmax/Dmin) ranging from 1.14 to 1.21. Furthermore, the four location points of dose-rate were used for main research. The effect of gamma irradiation (60Co) at different dose-rate on the anti-nutrient compound (phytic acid and antitrypsin) and color on soybean. Gamma irradiation on soybean was done with dose rates of 1.30; 3.17; 5.71 and 8.82 kGy/hour, respectively. Irradiation treatment condition for each samples was done at room temperature (28 ± 2 °C) ranging from 0.5 h to 55 h; depending on its dose rates. The purpose of this study was to investigate the influence of dose rate on the changes of anti-nutrient compound concentration and color (brightness) on soybean during radiation process. The results showed that k-value (degradation rate constant) gained to be used to explain the change rate of anti-nutrient compound concentration and color on soybean during radiation process. The obtained data indicated that radiation process in higher dose-rate (shorter time) was more effective to destroy anti-nutrient compound rather than in lower dose-rate (longer time). Furthermore, radiation process in higher dose-rate (shorter time) has also less detrimental effect on color of the soybean seeds and flour as compared to that of radiation process at lower dose-rate (longer time). This phenomenon showed that radiation process at the same dose was potential to optimize in terms of most appropriate combination treatment between the dose and irradiation time. Effects of gamma irradiation at different combination of dose-rate and time of exposure on the isoflavones contents of soybean. This research was purposed to study dose-rate and radiation influence on the change of soybean isoflavones concentrations during radiation process. The condition of irradiation (dose-rate and time combination) was done in accordance with the first research. Results showed that the change of isoflavone concentration provided adequately complex change pattern; furthermore, there was an increase of the isoflavone researched in the beginning of irradiation treatment. The increase of soybean isoflavone concentration in the same radiation dose was also influenced by dose-rate application. Lower dose-rate application resulted higher free isoflavone content, especially free daidzein and genistein. This finding showed that radiation process in the same dose has a potential to be able to be optimized by choosing the most appropriate combination on dose-rate and irradiation time. The third research was the verification of the results of the first and the second researches. Hypothesis testing was done by doing a research on the effect of gamma irradiation on the low and high dose at different combination of dose-rate and time on phytic acid and color of soybean. Gamma irradiation on soybean was done with dose-rates of 1.30; 3.17; 5.71 and 8.82 kGy/hour, respectively.The total of radiation doses accepted by the samples were 4.41 kGy and 44.1 kGy at a variety of time depending on their dose-rates. The purpose of this research was to study the hypothesis testing resulted from the previous research, namely: higher dose-rate (shorter time) would be more effective to decrease phytic acid, but it resulted minimum color change. Results showed that irradiation at the same dose; but radiation process was done in the higher dose-rate (shorter time) would provide better effectiveness of anti-nutrient compound (phytic acid). The irradiation condition also could keep better brightness (color). It is appropriate with hypothesis of this research.