自由空气中臭氧浓度升高对"武运粳21"稻米物性及食味品质的影响

Impact of free air ozone concentration enrichment on cooked rice (Wuyunjing 21) texture and palatability

  • 摘要: 研究表明不断升高的地表臭氧浓度使作物生长受抑、产量下降, 但对作物品质的影响则不太清楚, 特别是食味品质。本文于2009年和2010年在江苏省江都市小纪镇依托自由空气中臭氧浓度增高(free air ozone concentration enrichment, O3-FACE)技术平台, 以本地主栽水稻品种"武运粳21"为供试材料, 设置大气背景臭氧浓度和高臭氧浓度(比大气背景臭氧浓度高50%)2个水平, 研究了地表臭氧浓度升高对粳稻物性和食味品质的影响。物性分析仪测定结果表明, 高浓度臭氧使熟米硬度平均增加13.6%, 达显著水平。食味计测定结果显示, 高浓度臭氧使稻米香气、光泽、味道、口感和综合值分别下降0.8%(P>0.1)、6.2%(P<0.1)、2.6%(P<0.1)、5.1%(P<0.05)、4.3%(P<0.05), 使完整性增加2.0%(P<0.05)。不同年度间稻米物性和食味品质的差异较大, 但年度与臭氧间的交互作用未达显著水平。以上结果表明, 未来高浓度臭氧环境下生长的稻米蒸煮后将呈变硬趋势, 食味品质总体变劣。

     

    Abstract: Without appropriate control of ozone precursor emissions, tropospheric ozone concentration will be projected to increase significantly by the middle of this century. Rice (Oryza sativa L.), the most important food crop, has provided nutrition for more than half of the world's population over the centuries. Elevated ozone concentration has been noted to induce a series of physiological changes in rice crop. Such changes have included changes in the processes of photosynthesis, water relation, nutrient absorption/translocation and grain filling. Such altered physiological processes due to ozone exposure have likely affected the physical and chemical properties of rice grain and thus grain quality. To date, most studies on rice response to ozone stress have focused on growth and yield with little known issues on the effects of ozone on grain quality, especially the taste of edible crops. To investigate the effects of elevated ozone concentration on the texture and taste of cooked rice, a unique free air ozone concentration enrichment (ozone-FACE) experiment was conducted in two consecutive rice growing seasons (2009 and 2010). The FACE experiment was located in Xiaoji Town in Jiangdu County of Jiangsu Province, China (119°42′0′′E, 32°35′5′′N). A native Japonica rice cultivar "Wuyunjing 21" was exposed to ambient or elevated ozone concentration of 50% above ambient value. Texture analyzer measurements showed that the hardness of cooked rice increased by 13.6% (P < 0.05) under elevated ozone concentration. Sensory analyzer evaluation of taste also showed that elevated ozone concentration respectively decreased aroma, luster, flavor, taste and integrated value by 0.8% (P > 0.1), 6.2% (P < 0.1), 2.6% (P < 0.1), 5.1% (P < 0.05) and 4.3% (P < 0.05) and increased intactness by 2.0% (P < 0.05). While the yearly effect was significant for all texture and taste variables of cooked rice, the interaction between year and ozone was in the most cases not detected. The above results suggested that rice grown under future high ozone environments will have greater hardness and deteriorated taste properties after cooking.

     

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