Food Microbiology and Biotechnology, Hamburg School of Food Science , University of Hamburg, Biocenter Klein Flottbek , Ohnhorststr. 18 , D-22609 Hamburg , Germany.
August Storck KG , R&D Chocolates , Waldstr. 27 , D-13403 Berlin , Germany.
J Agric Food Chem. 2018 May 9;66(18):4660-4673. doi: 10.1021/acs.jafc.8b01216. Epub 2018 Apr 26.
Activity-guided fractionation in combination with sensory analytics, LC-TOF-MS, and 1D/2D-NMR spectroscopy enabled the identification of the bitter tasting diarylheptanoids asadanin, giffonin P, and the previously not reported ( E)-7,9,10,13-tetrahydroxy-1,7-bis(2-hydroxyphenyl)hept-9-en-11-one and 4,12,16-trihydroxy-2-oxatricyclo[13.3.1.1]-nonadeca-1(18),3,5,7(20),8,15,17-heptaen as well as the yet unknown astringent compounds 2-(3-hydroxy-2-oxoindolin-3-yl) acetic acid 3- O-6'-galactopyranosyl-2″-(2″oxoindolin-3″yl) acetate and 3-( O-β-d-glycosyl) dioxindole-3-acetic acid in Cimiciato-infected hazelnuts exhibiting a bitter off-taste. Quantitative LC-MS/MS studies, followed by dose/activity considerations confirmed for the first time asadanin to be the key contributor to the bitter taste of Cimiciato-infected hazelnuts. Furthermore, quantitative studies demonstrated that neither the physical damage alone nor a general microbial infection is able to initiate a stress-induced asadanin generation, but most likely either specific Cimiciato-specific microorganisms associated with the bugs or specific chemical stimulants in the bugs' saliva is the cause triggering asadanin biosynthesis. Finally, also germination was found for the first time to activate diarylheptanoid biosynthesis, resulting in higher contents of bitter tasting phytochemicals and development of the bitter off-taste.
活性导向分离与感官分析、LC-TOF-MS 和 1D/2D-NMR 光谱相结合，可鉴定出苦味二芳基庚烷类化合物 asadanin、giffonin P 以及以前未报道的（E）-7,9,10,13-四羟基-1,7-双（2-羟基苯基）庚-9-烯-11-酮和 4,12,16-三羟基-2-氧杂三环[13.3.1.1] -nonadeca-1(18),3,5,7(20),8,15,17-heptaen 以及尚未明确的涩味化合物 2-(3-羟基-2-氧代吲哚啉-3-基)乙酸 3-O-6'-半乳糖吡喃基-2″-(2″氧代吲哚啉-3″基)乙酸酯和 3-(O-β-d-糖苷基)二氧吲哚-3-乙酸在表现出苦味的榛子中。定量 LC-MS/MS 研究，随后进行剂量/活性考虑，首次证实 asadanin 是榛子感染 Cimiciato 后产生苦味的主要原因。此外，定量研究表明，仅物理损伤或一般微生物感染都不能引发应激诱导的 asadanin 生成，而是与昆虫相关的特定 Cimiciato 特异性微生物或昆虫唾液中的特定化学刺激物很可能是触发 asadanin 生物合成的原因。最后，还首次发现发芽会激活二芳基庚烷类生物合成，导致苦味植物化学物质含量更高，并产生苦味。
