Kavitake Digambar, Techi Mana, Abid U K, Kandasamy Sujatha, Devi Palanisamy Bruntha, Shetty Prathapkumar Halady
Department of Food Science and Technology, Pondicherry University, Pondicherry, 605014 India.
J Food Sci Technol. 2019 Apr;56(4):1766-1774. doi: 10.1007/s13197-019-03608-w. Epub 2019 Mar 5.
Exopolysaccharide (EPS) produced by KR780676 from an Indian fermented food () has been characterized as galactan in earlier report. In this study, the galactan EPS was irradiated at different doses (0, 4, 8, and 16 kGy) using Co as γ-source and effect of γ-irradiation on physico-chemical and antioxidant potential of galactan EPS was studied. Color and flow properties showed moderate change after the γ-irradiation treatment. Particle size analysis and scanning electron microscopy exhibited significant breakdown of the EPS particles into smaller average hydrodynamic diameter size from 495.54 to 198.44 nm with increasing irradiation doses. Overall, pH showed decrease, while the water activity showed an increasing trend with the increasing irradiation dose. No significant effect was observed in the functional groups of EPS as revealed in the FT-IR spectroscopic analysis. After the treatment, semi-crystalline nature of the EPS changed to amorphous as shown in XRD analysis due to the breakdown. Antioxidant activities of galactan EPS increased marginally after the treatment. However, hydroxyl radical scavenging activity increased significantly from 48 to 67%. Changes in physico-chemical and antioxidant properties of galactan EPS with γ-irradiation treatment altered the functional properties of EPS positively, making it more suitable for wider application in the food industry.
在早期报告中，从印度发酵食品中分离出的菌株KR780676所产生的胞外多糖（EPS）被鉴定为半乳聚糖。在本研究中，以钴作为γ射线源，对该半乳聚糖EPS进行不同剂量（0、4、8和16千戈瑞）的辐照，并研究γ辐照对半乳聚糖EPS的物理化学性质和抗氧化潜力的影响。γ辐照处理后，颜色和流变性质发生了适度变化。粒度分析和扫描电子显微镜显示，随着辐照剂量的增加，EPS颗粒显著分解为平均流体动力学直径更小的颗粒，从495.54纳米降至198.44纳米。总体而言，pH值降低，而水分活度随辐照剂量增加呈上升趋势。傅里叶变换红外光谱分析表明，EPS的官能团未观察到显著影响。处理后，XRD分析显示，由于分解，EPS的半结晶性质转变为无定形。处理后半乳聚糖EPS的抗氧化活性略有增加。然而，羟基自由基清除活性从48%显著提高到67%。γ辐照处理后半乳聚糖EPS的物理化学和抗氧化性质的变化积极地改变了EPS 的功能特性，使其更适合在食品工业中更广泛地应用。
