Abstract:

In order to realize the quality directional control and establish the quality evaluation system of open-field cultivation with big-trellis for‘Daqing grape’ （Vitis vinifera L. Daqing）， at fruit mature stage， the related components of chemical， texture indicators and volatile organic compounds of ‘Daqing grape’ fruits at different spatial positions on the big-trellis and per grape-cluster were determined by texture profile （TPA） analysis and gas chromatography-ion mobility spectrometry （GC-IMS） technology. The results showed that compared with‘the middle fruit of big-trellis’（TMF） and‘the anterior fruit of big-trellis’（TAF）， the contents of total sugar （Ts） and vitamin c （Vc） in‘the posterior fruit of big-trellis’（TPF） fruit significantly （P<0.05） increased by 8.92% and 10.38%， 22.29% and 62%， respectively， but total acid （Ta），TAF fruit had the highest content， which increased by 11.81% and 17.21%， respectively， compared with TMF and TPF； the contents of soluble solids （Tss）， Ts and Vc of ‘the shoulder fruit of single ear grapes’（TSF） were significantly （P<0.05） higher than those of the tip fruit of single ear grapes（TTF）， and increased by 5.62 %， 6.10 % and 13.02 %， respectively. The Ta content of TTF was the highest， which was 9.46% higher than that of TSF. The analysis of physical indicators showed that the single grain weight and hardness of TPF fruit were higher than those of TMF and TAF， and increased by 14.84 % and 19.12 %， 4.44 % and 5.36 %， with significant differences （P<0.05）； the fruit single grain weight and hardness of TSF were higher than those of TTF， and with increasing of 6.02 % and 3.22 %. The visualization analysis of volatile organic compounds for fruit by GC-IMS technology showed that TAF fruits possessed the aroma characteristics of grass and malt. TMF showed a kind of fat aroma； and the fruit （pineapple， citrus）， green grass aroma characteristics were shown at TPF； concomitantly， the peak volume of esters and terpenoids in TPF fruit was significantly （P<0.05） higher than those in TMF and TAF， such as ethyl acetate， ethyl propionate， α-terpinene， etc.， with increasing of 602.00%， 98.10%， 372.13% and 5 897.80%， 744.00%， 1 969.28% ； and the aromas of green grass and cream （E-2-hexenal， 3-hydroxy-2-butanone） were prominent in TTF， while the aroma of fruit and nut （n-pentyl butanoate， acetoxyacetone， guaiacol） were obvious in TSF； the accumulation of some esters and terpenoids （ β-pinene， α-phellandrene， ethyl acetate， etc. ） in the TSF fruit were significantly （P<0.05） higher than that in the TTF， with the increasing of 27.68%， 50.88%， and 785.43%.This paper combined the chemical indicators， with physical indicators and volatile organic compounds characteristics， the quality orders of ‘Daqing grape’ fruits at different spatial positions on the big-trellis were TPF>TMF>TAF， and TSF>TTF at different spatial positions of per grape-cluster. It was found that there were differences in fruit quality and volatile organic compounds at different spatial positions on the big-trellis in open field cultivation of ‘Daqing grape’， and it also showed that quality differences of per grape-cluster fruit at different spatial positions. Above results indicated that the importance of directional regulation of pre-harvest quality and establishment quality evaluation system for‘Daqing grape’ fruit， to guide post-harvest fresh-keeping and supply of different target markets.

Key words: Daqing grape （Vitis vinifera L.， Daqing）, open field cultivation of big-trellis, spatial position, fruit quality, GC-IMS technology, volatile organic compounds

摘要：

为了探究露地栽培‘大青葡萄’（Vitis vinifera L. Daqing）架面及单穗不同位置果实理化指标及挥发性物质的特点，并建立其果实质量评价体系，在果实成熟期，通过常规指标检测、全质构分析及气相离子迁移谱（GC-IMS）技术，测定了宁夏‘大青葡萄’架面及单穗不同位置果实的相关品质指标。结果表明：架面后部果实总糖和Vc含量较中部和前部果实分别显著（P<0.05）提高了8.92%、10.38%和22.29%、62.00%；总酸含量最高的是前部果实，较中部和后部分别高出11.81%、17.21%。单穗肩部果实在可溶性固形物、总糖、Vc含量上均显著（P<0.05）的高于尖部，分别高出5.62%、6.10%、13.02%；总酸含量最高的是尖部果实，较肩部高出9.46%。质构指标分析发现，架面后部果实在单粒重和硬度上较中部、前部果实分别高出14.84%、19.12%和4.44%、5.36%，存在显著差异（P<0.05）；单穗肩部果实在单粒重和硬度上均高于尖部，分别高出6.02%、3.22%。通过气相离子迁移谱技术对挥发性物质分析发现，架面前部果实表现出青草、麦芽香气特点；中部果实体现脂肪香气；后部果实具备水果、青草香气特征；在一些酯类和萜烯类物方面，后部果实与中部和前部位置果实存在显著差异（P<0.05）。单穗尖部果实青草和奶油香气表现突出，肩部果实则是果香和坚果香味较为明显；肩部果实一些脂类物质和萜烯类物质（β-蒎烯、α-水芹烯、乙酸乙酯等）的积累量显著（P<0.05）高于尖部的果实，分别高出27.68%、50.88%、785.43%。结合常规品质指标、质构指标以及挥发性物质特征，‘大青葡萄’果实在架面不同空间位置的品质高低综合排序为后部>中部>前部；单穗不同部位的果实为肩部优于尖部。露地大棚架栽培‘大青葡萄’存在架面不同空间位置上的果实品质与挥发性物质上的差异，并且单穗果实同样表现出不同部位的品质区别。研究结果为宁夏露地大棚架栽培‘大青葡萄’建立了果实质量评价体系，以指导采后保鲜与供应不同目标市场。

关键词: 大青葡萄, 露地大棚架栽培, 空间位置, 果实品质, GC-IMS技术, 挥发性物质