Capsaicin accumulation is related to nitrate content in placentas of habanero peppers (Capsicum chinense Jacq.)

BACKGROUND: The presence of capsaicin, the pungent principle of peppers, is restricted to the fruits of hot cultivars. This compound, which is produced in the fruits' placenta, requires 3 mol of nitrogen to be formed. Hence nitrogen availability may affect pepper pungency through its content in the fruit tissues. On the other hand, potassium may also affect pepper pungency given its positive effect on fruit development. In order to address this issue, plants of habanero pepper (Capsicum chinense Jacq.) were hydroponically cultured with various doses of nitrate and potassium and the contents of these ions and capsaicin were analyzed in the different fruit tissues. RESULTS: Treatments did not produce major effects on pod yield or size during the experimental period, and pepper pods from plants growing under low nitrate concentrations presented no significant differences in total nitrate content. However, lower nitrate, as well as low capsaicin contents, were found in the isolated placentas from peppers grown on the lowest nitrate doses. Variations in potassium availability resulted in differences in pod production per plant, but not in capsaicinoid accumulation. CONCLUSION: Under the assayed conditions, nitrate content in the placenta affects capsaicin synthesis. Copyright © 2010 Society of Chemical Industry     

Volatile compounds and capsaicinoid content of fresh hot peppers (Capsicum annuum L.) of different Calabrian varieties

BACKGROUND: Because of the great variability in size, shape, colour, pungency and aroma of Calabrian Capsicum annuum(hot pepper), this study was carried out to furnish producers with information on volatile compounds and capsaicinoid content useful for the genetic improvement of this species. Fully ripened fresh peppers of the most widely cultivated varieties were studied. Capsaicinoid content was determined by reverse phase high‐performance liquid chromatography/diode array detection (RP‐HPLC/DAD). Volatile compounds were determined by headspace solid phase microextraction/gas chromatography/mass spectrometry (HS‐SPME/GC/MS). RESULTS: Sixty‐four volatile compounds were identified, the main classes being alcohols, aldehydes, terpenes and aliphatic branched‐chain hydrocarbons. The ‘Naso di cane’ (C. annuumvar. abbreviatum) variety contained the lowest amount of volatiles, especially alcohols and aldehydes, while the highest levels of capsaicin and dihydrocapsaicin were found in ‘Vulcan’ and ‘Corno di capra’ varieties. CONCLUSION: From statistical evaluation of the data obtained, each variety showed a typical composition of capsaicinoids and volatiles determining the taste and odour of the hot peppers. These results should be useful in the context of research aimed at selecting varieties with the best sensory characteristics. Copyright © 2009 Society of Chemical Industry     

Volatile constituents of Cachucha peppers (Capsicum chinense Jacq.) grown in Cuba

The steam volatile components of three cultivars of Cachucha mature peppers (Capsicum chinense Jacq.) were isolated by steam-distillation-continuous-extraction and analysed using GC and GC-MS. The composition of volatile compounds of the peppers differs clearly for the different cultivars. The content of volatile compounds, responsible for the flavour of Cachucha peppers, varied between 110.71 and 302.53 mg kg⁻¹. One hundred and thirty-six compounds were identified, from which hexyl isopentanoate, hexyl pentanoate, hexyl 2-methylbutanoate, 3,3-dimethylcyclohexanol, γ-himachalene and germacrene D were the major ones.     

利用低场核磁共振技术研究二氧化碳气调贮藏下蛋清水分变化

本文以25℃下二氧化碳气调贮藏实验组和不作特殊处理对照组鸡蛋为研究对象,分别贮藏0、10、20、30、40 d,测定其新鲜度,并利用低场核磁共振分析仪测定蛋清水分情况及横向弛豫时间,探究在不同贮藏条件下,蛋清水分状态变化和迁移的规律。结果表明,贮藏过程中,实验组不易流动水含量无显著变化,T23显著升高（p<0.05）;而对照组不易流动水含量显著上升（p<0.05）,T23显著降低（p<0.05）,说明二氧化碳气调贮藏可以抑制蛋白质结合水能力的降低。通过相关性分析可知,实验组T22值与哈夫单位和蛋黄指数相关系数为-0.998（p<0.05）和+0.997（p<0.05）,对照组T22值与蛋清p H相关系数为+1.000（p<0.01）,表明T22可预测鸡蛋的新鲜度。      

从啤酒中苯的含量调查谈食品级二氧化碳的质量控制

采用顶空-气相色谱法检测啤酒中的苯含量，方法的最低检出限为1．0μg／L。变异系数3．9％，回收率91％．检测了77种国产啤酒样品，71个样品未检出；6个样品检出了苯．其含量范围从1．9～7．1μg/L.检测国内市场销售的7种进口啤酒，均未检出苯。虽然所有啤酒的苯含量都没有超过10μg/L（世界卫生组织饮用水的限量标准），但个别样品较高的苯含量表明，建立食品级二氧化碳质量控制体系的重要性。     

Enrichment of tocols from rice germ oil using supercritical carbon dioxide

An efficient process was developed for enrichment of tocols from rice germ oil (RGO) using supercritical carbon dioxide (SC‐CO₂). Tocols were efficiently enriched in residue by removal of fatty acid methyl ester from the esterified RGO using SC‐CO₂. The enrichment of tocols was carried out at an operating pressure of 12.4–15.8 MPa, an operating temperature of 40–60 °C and a carbon dioxide flow rate of 5.0 L min^?1. The combination of 13.8 MPa pressure and 60 °C temperature was selected as the most suitable for efficient enrichment of tocols. The level of tocols (1270 mg/100 g) in the residue obtained at these operating conditions was six times higher than the tocols level (192 mg/100 g) of the starting material, namely esterified RGO. There were no significant differences in relative percentages of tocols homologues between esterified RGO and the residue obtained by SC‐CO₂ extraction.     

Effects of supercritical and liquid carbon dioxide extraction on hemp (Cannabis sativa L.) seed oil

The increase in the popularity of hemp-based products is mainly linked to the presence of non-psychoactive cannabinoids that provide relief from aches, pain and anxiety. In this study, hemp seed oils were produced by two innovative and environmentally friendly extraction techniques: supercritical and liquid carbon dioxide (CO₂) extraction. The chemical composition of the two oils was analysed and compared with that of a control oil obtained by solvent (n-hexane) extraction. Both oils obtained by liquid and supercritical CO₂ extraction presented interesting compositions: they contained large amounts of cannabinoids, polyphenols and tocopherols and were less oxidised than the control and contained a large amount of hexanal, which provided a pleasant aroma. The maximum cannabinoid content was found in the oil obtained by liquid CO₂ extraction (71.51 mg of cannabidiol per kg of oil and 113.92 mg of cannabinol per kg of oil). Carotenoids were prevalent in the oil obtained by supercritical CO₂ extraction (61.00 mg kg⁻¹ of oil).     

NaOH treatment reduces capsaicin content and pungency of ‘Makedoniko’ pepper (Capsicum annuum L.)

Pickled peppers are preferred by certain consumer groups at reduced pungency. To investigate the reduction in pepper pungency and capsaicin content, fresh ‘Makedoniko’ hot peppers were treated with 0, 0.5 or 1% NaOH before preserved in acid brine for 60 days. Pepper physicochemical traits were monitored following NaOH treatment and during preservation. Capsaicin content was measured in the beginning and at the end of preservation, and the peppers were also tested organoleptically. Preservation in acid brine induced the typical green–yellow product colour, increased firmness and decreased the dry mass in all treatments. NaOH‐treated pepper increased phenolics, chlorophyll and antioxidant content in dry mass during preservation faster than the control. Capsaicin content was reduced by 25 or 50% following 0.5 or 1% NaOH treatment, respectively. Pepper organoleptic pungency was also decreased following 1% NaOH treatment. NaOH reduces capsaicin content and pungency of ‘Makedoniko’ pepper, with minor effects on its processed product quality.     

高密度二氧化碳技术生产苹果浆工艺的优化

采用高密度二氧化碳技术对苹果浆进行处理,以期降低苹果浆中菌落总数,保留其原有颜色。研究考察高密度二氧化碳处理压力、温度、时间对苹果浆品质的影响,在此基础上,选取高密度二氧化碳处理压力、时间以及温度为影响因素,以菌落总数和色差为响应值,进行高密度二氧化碳处理工艺的响应面优化。结果表明:随着压力增大,时间延长以及温度提高,苹果浆中菌落总数和颜色变化呈现降低趋势;当高密度二氧化碳处理压力为20 MPa,温度为40℃,处理45 min时,苹果浆中菌落总数为1.5 lg cfu/m L,色差为1.02,与理论值相对误差均小于5%,表明回归模型真实可靠。      

炒米加工过程中二氧化硫含量的变化

试验选取了5种炒米原料,考察了不同加工参数、配料以及助剂对炒米中二氧化硫含量变化的影响.结果 表明,炒米的原料均未检出二氧化硫.炒米中的二氧化硫并非原料带入,而是在加工过程中产生.二氧化硫含量随着碳酸氢钠、碳酸钠、植物油的添加及加热时间的增加,未呈现规律性变化.随着加热温度的上升,炒米中二氧化硫的含量逐渐增加.加热温度...     

超临界CO2下酶催化脂质水解反应

近年来以超临界CO_2流体作为反应介质已成为化学和生物化学反应研究一个热点,以超临界CO_2流体为介质进行酶催化脂质水解反应,与其它非水相酶催化介质相比,有其独特优越性。该文介绍超临界CO_2流体特性及在超临界CO_2流体中影响酶催化脂质水解因素。     

Enrichment of tocopherols in modified soy deodorizer distillate using supercritical carbon dioxide extraction

Supercritical carbon dioxide (SC-CO₂) extraction of chemically modified Soy Deodorizer Distillate (DOD) at three levels of pressure (180–300 bar) and temperature (40–60 °C) to optimize the conditions for enrichment of tocopherols in the raffinate was carried out. After modification, soy DOD contained about 90% of fatty acid methyl esters (FAME), showed improved solubility in SC-CO₂, and better extraction rate. Since fatty acid methyl esters are more volatile, they are extracted preferentially over tocopherols and other high molecular weight compounds. Higher levels of pressure and temperature resulted in increased solubility of compounds with high molecular weight and tocopherols due to increased density of SC CO₂. So the extraction at higher pressures and temperatures resulted in a better yield of FAME along with tocopherols in the extract and this in turn decreased the degree of enrichment of tocopherols in the raffinate. However, specific level of pressure and temperature of extraction caused the increase in the solubility of FAME due to their volatility and results in enhanced enrichment of tocopherols in the raffinate. It was observed that the enrichment of tocopherols to ten times the original concentration of feed occurred at extraction pressure of 180 bar and temperature of 60 °C of SC-CO₂.     

Inactivation of yeasts in grape juice using a continuous dense phase carbon dioxide processing system

The effects of dense phase CO₂ processing parameters, including temperature (25 and 35 °C), CO₂ concentration (0, 85 and 170 g kg⁻¹) and pressure (6.9, 27.6 and 48.3 MPa), on yeast survival and sensory properties of grape juice were investigated. The dense phase CO₂ process resulted in more than a 6 log reduction in yeast population. As the CO₂ to juice concentration, temperature and pressure increased, the inactivation rate increased. CO₂ in the supercritical state was more effective in inactivating yeast than in the subcritical state. The process did not cause detectable flavor degradation. Dense phase CO₂ processing can be an effective non‐thermal alternative process for pasteurization of grape juice. Copyright © 2005 Society of Chemical Industry     

Inactivation of polyphenol oxidase from frozen red raspberry (Rubus idaeus L.) by high pressure carbon dioxide treatment

The effect of high pressure carbon dioxide (HPCD) treatment on polyphenol oxidase (PPO) from frozen red raspberry (Rubus idaeus L.) was evaluated. Moreover, the inactivation kinetics of its PPO was simulated by first‐order reaction theory. The minimum of PPO residual rate was 36.6% under 30 MPa and 55 °C for 60 min by HPCD treatment, while that was 66.8% at 55 °C for 60 min by thermal treatment. Moreover, the decimal reduction time of PPO decreased rapidly after HPCD treatment, compared to that of the thermal treatment. The thermal treatment at 55 °C takes a similar time to reach 10% PPO residual rate with HPCD treatment under 30 MPa at 35 °C. One reason for the results was that activation energy of PPO reduced from 98.9 to 14.6 kJ mol^?1 after HPCD treatment. Therefore, HPCD treatment showed stronger capacity to inactivate PPO from frozen red raspberry than the thermal treatment at same temperature.     

Measurements and thermodynamic modeling of the solubility of squalene in supercritical carbon dioxide

The solubility of squalene in supercritical carbon dioxide (SC-CO₂) was measured and it was analyzed together with the values obtained by Catchpole and von Kamp (1997). The results showed that the experimental values obtained in this work agreed with the order of magnitude of those reported in the literature and correlated well with the Chrastil equation. The thermodynamic modeling using the Peng–Robinson equation of state only correlated well with the experimental values obtained when the critical properties and acentric factor reported by Ruivo et al. (2004) were used. The values predicted for the solubility of squalene in SC-CO₂ using modeling employing the GC-EOS, were only of the same order of magnitude as the experimental values for pressures below 200 bar, and its performance was influenced by the value of the critical hard sphere diameter.     

Composition of clove (Syzygium aromaticum) bud oil extracted using carbon dioxide

Analysis of clove (Syzygium aromaticum L) bud oil extracted with liquid and supercritical carbon dioxide shows significant qualitative and quantitative compositional differences compared with oil obtained by the conventional hydrodistillation process. The parameters of pressure, temperature, contact time etc, and also the clove oil components, affect the extraction of the bud flavour from the spice.