Table_1_Differences in primary metabolism related to quality of raspberry (Rubus idaeus L.) fruit under open field and protected soilless culture growing conditions.docx

IntroductionThe raspberry (Rubus idaeus) fruit is characterized by good taste and high acceptability by consumers. Thus, the impact on the quality attributes and metabolites related to raspberry taste should be evaluated in crop alternatives such as the protected soilless culture. This study aimed to evaluate the metabolic changes during fruit development and postharvest of raspberry grown in open field and protected soilless culture and their relationship with quality parameters and sensory perception.
MethodsIn this study, the quality parameters and polar metabolites -sugar and amino acids- content were evaluated during raspberry ripening. In addition, ripe fruit was stored at 1 °C for five days, followed by one day of shelf life at 20 °C.
ResultsThe physiological and quality parameters showed typical changes during ripening in both growing conditions: a constant production of CO2, a drastic loss of firmness, an increase in weight and soluble solids content, loss of acidity, and a turning to red color from the green to fully ripe fruit stages in both growing conditions. Fruit from the protected soilless culture had significantly higher weight but a lower soluble solids content. The metabolic analysis showed differences in primary metabolites content during ripening and storage at 1 °C between both growing conditions. The raspberries grown in the open field showed higher contents of sugars such as D-glucose and D-fructose. On the contrary, the fruit from the protected soilless culture showed higher contents of some amino acids such as L-alanine, L-serine and L-valine, among others. The sensorial panel showed significant differences in the perception of the sweetness, acidity, color and firmness of ripe fruit from both growing conditions.
DiscussionThe present study provides interesting and useful results with direct commercial application for this alternative growing system, mainly in areas where soil and water scarcity are a reality.

引言
树莓（Rubus idaeus）果实以优良风味与极高的消费者接受度为显著特征。因此，针对保护性无土栽培（protected soilless culture）这类替代种植模式，有必要评估其对树莓风味相关品质属性与代谢物的影响。本研究旨在对比分析露地栽培（open field）与保护性无土栽培（protected soilless culture）的树莓，在果实发育及采后（postharvest）阶段的代谢变化，并探究其与品质参数及感官感知（sensory perception）的关联。

试验方法
本研究在树莓成熟过程中，对其品质参数及极性代谢物（polar metabolites）的含量进行了测定。此外，将成熟果实置于1℃条件下贮藏5天，随后在20℃环境下放置1天以模拟货架期（shelf life）。

结果
两种种植模式下的树莓在成熟过程中均呈现出典型的生理与品质变化规律：持续释放二氧化碳（CO₂）、硬度大幅下降、单果重与可溶性固形物含量（soluble solids content）上升、酸度降低，且果实从绿色转红直至完全成熟。保护性无土栽培的树莓单果重显著更高，但可溶性固形物含量更低。代谢分析显示，两种种植模式的树莓在成熟阶段及1℃贮藏期间，初生代谢物含量存在显著差异。露地栽培的树莓中，D-葡萄糖（D-glucose）与D-果糖（D-fructose）等糖类的含量更高；反之，保护性无土栽培的树莓中，L-丙氨酸（L-alanine）、L-丝氨酸（L-serine）和L-缬氨酸（L-valine）等部分氨基酸的含量更高。感官评定小组（sensorial panel）的结果表明，两种种植模式下的成熟树莓在甜度、酸度、色泽与硬度的感知上存在显著差异。

讨论
本研究获得了具有重要理论与应用价值的结果，可为该替代种植模式提供直接的商业化指导，尤其适用于土壤与水资源匮乏的地区。