柑桔中类柠檬苦素含量及分布研究

对几种柑桔品种果皮、种子、果汁中类柠檬苦素的含量进行了测定,结果表明,柑桔果实中不同部位类柠檬苦素含量不同,以种子中含量最高,果皮次之,而果汁中含量最低。不同品种间类柠檬苦素含量依次为:邓肯葡萄柚>琯溪蜜柚>南充实生甜橙>锦橙>大红袍红桔。     

Liquid chromatography–electrospray ionisation mass spectrometry method for the rapid identification of citrus limonoid glucosides in citrus juices and extracts

A rapid and selective liquid chromatography–electrospray ionisation mass spectrometry (LC–ESI-MS) method to screen citrus samples for limonoid glucosides and estimate their relative concentrations has been developed. This method utilises a phenyl stationary phase, whereas previous methods have relied on C-18. Samples may be analysed directly without treatment other than dilution. Peak areas from the extracted deprotonated molecular ion mass signals for individual limonoid glucosides were normalised against the sum of the areas to establish their relative concentrations. The method was successfully applied to the analysis of various juice, extracts, and liquid samples of partially purified limonoid glucosides.     

高效液相色谱法测定柑橘中的柠檬苦素类似物

建立了同时测定柑橘中柠檬苦素和诺米林2种苷元的高效液相色谱方法。色谱柱为Phenomenex C18(250mm×4.6mm,5μm),流动相为体积分数45%乙腈,流速为1.0mL/min,柱温为25℃,检测波长在210nm。经考察该方法可行性强,柠檬苦素和诺米林的平均回收率分别99.91%和98.28%,RSD分别为2.55%和2.30%。因此用该法测定了柑橘中的柠檬苦素和诺米林的含量,并取得了理想的结果。     

柑桔发酵酒脱苦技术研究

柑枯发酵酒中苦味物质主要由柠檬苦素,柚皮苷等组成,本研究采用吸附法,酶制剂等脱苦方法,确定最佳酶制剂脱苦工艺参数。     

水溶性食物纤维强化柑桔汁饮料的开发研究─再论中国产HB801吸附树脂对柑桔苦味物质的脱除效果

本试验对已吸附树脂脱苦处理后的柑桔皮果胶液，用于水溶性食物纤维强化柑桔汁饮料的开发进行了研究。在以前研究的基础上［１］，对３种吸附树脂不同处理的样品中残留的苦味成分柚皮苷和柠碱的含量，应用高效液相色谱仪进行了分析。证明了中国产ＨＢ８０１的脱苦效果稍优于目前国际果汁饮料业界常用的美国产ＡｍｂｅｒｌｉｔｅＸＡＤ－２等。同时还试制了已经ＨＢ８０１脱苦处理后的柑桔皮果胶液作为水溶性食物纤维的强化柑桔汁饮料。为使普通柑桔皮果胶液适用于饮料生产，本文作了一些探索。     

柑桔果实中天然柠檬苦素和诺米林的提取、鉴别与检测

柠檬苦素类化合物是柑桔果实中的一类重要的生物活性物质。采用溶剂2为提取液,水浴加热,提取温度50℃,提取时间60min,提取柑桔果实中柠檬苦素和诺米林,回收率分别为90.4%和91.1%。薄层层析(TLC)与高效液相色谱(HPLC)两种方法相结合可以有效地鉴别和检测果实组织中的柠檬苦素和诺米林。HPLC的定性、定量检测条件为:C18柱,4.3mm×25cm,流动相为甲醇:乙腈:磷酸缓冲液(pH=3.5)=10∶40∶39,检测波长210nm,该体系中两组分检测限(S/N=3)均为0.03μg/g,RSD(n=5)分别为6.48%和2.90%。用本法提取、鉴别和检测柑桔果实中的柠檬苦素和诺米林较为准确、简单及方便。     

Antioxidant and antimicrobial activities of the methanol extracts from pummelo (Citrus grandis Osbeck) fruit albedo tissues

The present study was conducted to evaluate the antioxidant and antimicrobial properties of methanol (100 and 80% aqueous) extracts of pummelo fruits albedo (Citrus grandis Osbeck). The antioxidant and antibacterial activity for crude extracts and isolated compounds were evaluated using free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Paper disc diffusion method. A 100% Methanol (MeOH) extract was steeped in water at different pH levels and partitioned with ethyl acetate (EtOAc) to give basic, acidic, neutral, and phenolic fractions. The neutral extract was found to possess maximum antioxidant and antibacterial activity. Thereafter, neutral extract was carried out on a silica gel column and eluted with hexane:EtOAc:acetone and preparative TLC (PTLC) to give oil buntan compound, linoleic acid methyl ester, β-sitosterol, sigmasterol, limonin, nomilin and meranzin hydrate were isolated. While, 80% MeOH extract was fractionated also using a silica gel column and PTLC to give isomeranzin hydrate, p-coumaric acid and caffeic acid compound. The extract concentration providing 50% inhibition (IC₅₀) was as follows; oil buntan compound 95 μg/mL, caffeic acid 45 μg/mL, p-coumaric acid 105 μg/mL, limonin + nomilin (mixture) 135 μg/mL was lower than that of synthetic antioxidant butylated hydroxyanisole (BHA) 40 μg/mL. The inhibitory zone (mm) of bacteria tested was 2.9–4.1 mm caffeic acid and 11.6–15.1 mm p-coumaric acid.     

On the non-enzymatic liberation of limonin and C17-epilimonin from limonin-17-β-d-glucopyranoside in orange juice

Limonin is well-known to induce the so-called “delayed” bitterness which is developing during standing and/or processing of orange juice. The objective of this study was to investigate the hydrolytic liberation of limonin from its precursor limonin-17-β-d-glucopyranoside in aqueous model solutions and orange juice samples. Quantitative model studies on the degradation of limonin-17-β-d-glucopyranoside under acidic conditions as well as during storage of orange juice revealed the formation of limonin besides a second hydrolysis product of yet unknown structure. After isolation, the structure of that compound was unequivocally determined for the first time as the C₁₇-epimer of limonin, named C₁₇-epilimonin. In order to investigate the generation of these triterpenoid lactones during storage as well as heat-treatment of orange juice, freshly squeezed orange juice was stored for up to 4 weeks at 4 and 20 °C or was heated at 70 and 100 °C and, then, both limonoids were quantitatively determined by means of high performance liquid chromatography-mass spectrometry/mass spectrometry (multiple reaction monitoring). The data obtained showed first evidence for the use of the C₁₇-epilimonin/limonin ratio as a suitable marker for the analytical determination of the thermal input applied during processing orange juice products.     

Hydrotropic extraction of bioactive limonin from sour orange (Citrusaurantium L.) seeds

Limonoids are potential bioactive compounds present only in citrus among fruits and vegetables. A new process for extraction of limonoid aglycones from sour orange (Citrus aurantium L.) seeds was investigated using aqueous hydrotropic solutions. The extraction efficiency was dependent on hydrotrope concentration, extraction temperature and percent of raw material loaded. Two hydrotropes such as sodium salicylate (Na-Sal) and sodium cumene sulphonate (Na-CuS) were studied using Box-Behnken experiment design. Response surface analysis (RSA) of data was performed to study the effect of parameters on extraction efficiency. Prominent limonoid aglycone such as limonin was extracted and quantified for process optimization. Both hydrotropes gave maximum limonin yield at 2 M concentration, extraction temperature of 45 °C and 10% solid loading. A maximum limonin yield of 0.65 mg/g seeds was obtained using Na-CuS whereas only 0.46 mg/g seed was obtained using Na-Sal. Using this process, the use of organic solvents can be reduced dramatically to keep the process environmental friendly for the extraction of bioactive compounds.     

柑桔酒苦味的产生及脱苦

柑桔酒苦味主要来源于两个方面：一方面在柑桔汁加工过程中产生;另一方面来源于柑桔酒酿选及陈酿过程。本文根据苦味的产生,对如何分阶段将柑桔酒脱苦作了综述。