Liu Xin, Gmitter Frederick G, Grosser Jude W, Wang Yu
Citrus Research and Education Center, University of Florida Lake Alfred Florida 33850 USA
Department of Food Science and Human Nutrition, University of Florida Gainesville Florida 32611 USA.
RSC Adv. 2023 Feb 15;13(8):5590-5599. doi: 10.1039/d2ra08182b. eCollection 2023 Feb 6.
Citrus greening disease or Huanglongbing (HLB) is one of the most destructive diseases affecting all varieties of citrus worldwide. Aimed at optimizing the scion/rootstock combination to improve HLB-affected orange juice quality, a flavoromics strategy was used to investigate the effects of six different rootstocks (CH, blue, 1804, FG, SW, and Volk) on flavor quality of HLB affected orange juices. A sensory quality test was conducted by a panel to evaluate the sensory attributes of different orange juices. The orange juice from rootstock CH had the best flavor quality with highest sweetness, low sourness and bitterness, while rootstocks Volk and FG produced the poorest quality orange juices. Chemical profile analysis resulted in semi-quantification of 89 metabolites including 57 nonvolatile compounds and 32 volatile compounds using UHPLC-MS and GC-MS, respectively. Canonical correlation analysis indicated that some specific sugar and sugar alcohols including raffinose, xylose, rhamnose, glucose, sorbitol, and myo-inositol made a strong positive contribution to sweetness. Meanwhile, several amino acids including alanine, glutamic acid, proline, arginine, serine, asparagine, as well as aspartic acid were responsible for positive flavor quality. On the other hand, some nucleotides and limonin increased bitterness. In addition, KEGG pathway enrichment analysis demonstrated different rootstocks could affect aminoacyl-tRNA biosynthesis, ABC transporters, and monoterpenoid biosynthesis. These results indicated different rootstocks can change specific metabolites and thus affect the flavor quality of orange juices. This study also provides reference for optimizing the scion/rootstock combination to improve HLB-affected orange juice quality.
柑橘黄龙病（HLB）是影响全球所有柑橘品种的最具破坏性的病害之一。为了优化接穗/砧木组合以提高受HLB影响的橙汁质量，采用了风味组学策略来研究六种不同砧木（CH、blue、1804、FG、SW和Volk）对受HLB影响的橙汁风味质量的影响。由一个专业小组进行感官质量测试，以评估不同橙汁的感官属性。来自砧木CH的橙汁风味质量最佳，甜度最高，酸度和苦味较低，而砧木Volk和FG生产的橙汁质量最差。化学特征分析分别使用超高效液相色谱-质谱联用仪（UHPLC-MS）和气相色谱-质谱联用仪（GC-MS）对89种代谢物进行了半定量分析，其中包括57种非挥发性化合物和32种挥发性化合物。典型相关分析表明，一些特定的糖类和糖醇类物质，包括棉子糖、木糖、鼠李糖、葡萄糖、山梨醇和肌醇，对甜度有很强的正向贡献。同时，几种氨基酸，包括丙氨酸、谷氨酸、脯氨酸、精氨酸、丝氨酸、天冬酰胺以及天冬氨酸，对风味质量有正向作用。另一方面，一些核苷酸和柠檬苦素增加了苦味。此外，KEGG通路富集分析表明，不同的砧木会影响氨酰-tRNA生物合成、ABC转运蛋白和单萜生物合成。这些结果表明，不同的砧木可以改变特定的代谢物，从而影响橙汁的风味质量。本研究也为优化接穗/砧木组合以提高受HLB影响的橙汁质量提供了参考。
