Servili Maurizio, Minnocci Antonio, Veneziani Gianluca, Taticchi Agnese, Urbani Stefania, Esposto Sonia, Sebastiani Luca, Valmorri Sara, Corsetti Aldo
Dipartimento di Scienze Economico-Estimative e degli Alimenti, Sezione di Tecnologie e Biotecnologie degli Alimenti, Università degli Studi di Perugia, Via S. Costanzo, 06126 Perugia, Italy.
J Agric Food Chem. 2008 Aug 13;56(15):6389-96. doi: 10.1021/jf8007019. Epub 2008 Jul 16.
Olive fruits contain high concentrations of phenols that include phenolic acids, phenolic alcohols, flavonoids, and secoiridoids. The final concentration of phenols is strongly affected by brine conditions. The factors involved in modification by brine are still partially unknown and can include hydrolysis of secoiridoid glucosides and the release of hydrolyzed products. In this study olives from various Italian cultivars were processed by natural fermentation (e.g., without a preliminary treatment of olives with NaOH) using a selected Lactobacillus strain. Processed olives are characterized by a low phenolic concentration of phenols, consisting mainly of phenyl alcohols, verbascoside, and the dialdehydic form of decarboxymethylelenolic acid linked to (3,4-dihydroxyphenyl)ethanol (3,4-DHPEA-EDA), whereas a high level of phenols occurs in olive brine from all the cultivars studied. Olives of the Coratina cultivar, control and with fermentation by Lactobacillus pentosus 1MO, were analyzed in a frozen hydrated state by cryo scanning electron microscopy and energy-dispersive X-ray microanalysis, on both surface and transversal freeze-fracture planes. Structural modifications, found in olives after fermentation, may explain the phenol release in brine.
橄榄果实含有高浓度的酚类物质，包括酚酸、酚醇、黄酮类化合物和裂环烯醚萜类化合物。酚类物质的最终浓度受盐水条件的强烈影响。盐水改性所涉及的因素仍部分未知，可能包括裂环烯醚萜糖苷的水解以及水解产物的释放。在本研究中，使用选定的乳酸杆菌菌株通过自然发酵（例如，不对橄榄进行氢氧化钠预处理）处理来自意大利不同品种的橄榄。加工后的橄榄的特点是酚类物质浓度低，主要由苯醇、毛蕊花糖苷以及与（3,4 - 二羟基苯基）乙醇（3,4 - DHPEA - EDA）相连的脱羧甲基乙二醛形式的去甲肾上腺素酸组成，而在所研究的所有品种的橄榄盐水中酚类物质含量都很高。对科拉蒂纳品种的橄榄，对照组以及经戊糖片球菌1MO发酵的橄榄，在冷冻水合状态下通过低温扫描电子显微镜和能量色散X射线微分析，对其表面和横向冷冻断裂面进行了分析。发酵后橄榄中发现的结构变化可能解释了酚类物质在盐水中的释放。
