Improvement of tasty and nutrient enrichment of leaf vegetables grown hydroponically by introducing sweeteners, ascorbic acid and flavors.

为了生产低硝酸盐含量的水培叶菜，在低硝酸盐浓度的营养液中添加硅酸盐进行了小松菜的水培。低硝酸盐处理下，小松叶片中硝酸盐含量低于硝酸盐浓度正常的对照，添加硅酸盐可以缓解营养液中硝酸盐浓度过低对植物生长的影响。但营养液中硅酸盐浓度与小松叶片中硝酸盐浓度之间的关系尚不清楚。为了生产出美味且营养丰富的蔬菜，研究了通过根部向叶菜中引入抗坏血酸、甜菊糖甜味剂和香精三种成分。结果表明，这三种成分可通过根部大量引入蔬菜，感官评价表明，三种成分处理后的植物叶片的甜味明显高于对照，苦味明显降低，但口感与对照相当。在甜瓜精华和薄荷提取物处理下，植物叶片的风味明显优于对照组。甜瓜香精处理的生菜感官评价得分高于薄荷提取物处理和对照处理。结果表明，添加甜味剂、抗坏血酸和香料可以改善叶菜的口感和营养，但由于这些成分的加入，叶菜的叶子出现了明显的萎蔫现象。有必要设计一种防止萎蔫的引进方法。

To product leaf vegetables with low nitrate content in hydroponics, komatsuna (Brassica Rapa L.) was cultivated by adding silicate to nutrient solutions with low nitrate concentration. In the low nitrate treatment, nitrate content in komatsuna leaves is smaller than that of control (normal nitrate concentration) and a delay of plant growth due to low nitrate concentration of nutrient solutions was alleviated by adding silicate. But the relationship between silicate concentration in nutrient solutions and nitrate concentration in komatsuna leaves was not observed clearly.To product tasty and nutrient enrichment vegetables, it is studied to introduce three components (ascorbic acid, stevia sweeteners and flavors) to leaf vegetables grown hydroponically through their roots. It is found significant amount of these three components can be introduced to vegetables through the roots and sensory evaluation showed that plant leaves treated with three components were significantly more sweet than that of control and bitterness was reduced while tastefulness was the same level as that of control. In both treatments with muskmelon essence or peppermint extract, plant leaves had significantly better flavor than in control. Higher score of sensory evaluation was recorded on the lettuce treated with muskmelon essence than that with peppermint extract and with control.These results showed that taste and nutrient of leaf vegetables could be improved by introducing sweeteners, ascorbic acid and flavors, but the leaves of vegetables showed visible wilting due to introduce these components. It is necessary to devise a introducing method to prevent the wilting.