Capsaicinoids quantification in chili peppers cultivated in the state of Yucatan,Mexico

Capsaicinoids are a group of 12 or more related alkaloids responsible of the pungent sensation in fruits of the genus Capsicum. Capsaicin [(E)-N-(4-hydroxy-3-methoxybenzyl)-8-methyl-6-nonenamide] and dihydrocapsaicin are responsible for more than 90% of the pungency. This work describes the quantitative analyses by gas chromatography of the content of capsaicin and dihydrocapsaicin in the pericarp, placenta, and seeds of seven cultivars of chili peppers cultivated in the state of Yucatan, Mexico [chawa, dulce, sukurre, xcat’ik (Capsicum annuum L. var. annuum), maax (Capsicum annuum L. var. aviculare), and habanero orange and habanero white (Capsicum chinense Jacq.)]. Capsaicin content was higher, as expected, in the fruits of habanero orange and habanero white, followed by sukurre, chawa, xkat’ik, and maax. Dihydrocapsaicin content did not follow the same scheme, being higher in the fruits of sukurre, followed by chawa, habanero white, habanero orange, and maax. Xcat’ik showed minor quantities of dihydrocapsaicin, while dulce chili contained only traces of these two alkaloids.     

Cu2O/Cu2S 复合材料制备及可见光催化降解甲基橙的研究

通过水热法制备Cu₂O/Cu₂S 复合材料对甲基橙(MO) 进行光催化降解实验。在Cu₂O 中引入S 元素, 通过 改变Cu/S 投加摩尔比, 从而得到不同Cu/S 的复合材料。利用XRD、SEM、UV-vis、EIS 等手段对材料进行表征, 并 对MO 进行光催化降解实验。XRD 结果表明, 随着S 含量的增多, Cu₂S 的衍射强度逐渐上升, Cu₂O 的f111g 晶面 衍射强度逐渐降低。SEM 结果表明Cu₂S 能较好地包覆在Cu₂O 八面体的表面。通过UV-vis 和EIS 结果计算得知, 复合材料带隙为1.49 eV, 电荷转移电阻大幅降低。降解实验结果表明复合材料最佳Cu/S 投加摩尔比为15 : 1, 其在 100 min 时对MO (100 mL, 10 mg/L) 降解率达到91.4%, 明显高于纯Cu₂O 对于MO 的降解率(60.3%)。猝灭实验表 明了?OH 和 ?O₂ ^-在光催化过程中起到主要作用。     

Solar-based photoreduction of methyl orange using zeolite supported photocatalytic materials

A new class of novel photocatalysts has been prepared by supporting TiO₂ on the zeolite matrix by various routes of synthesis. Different transition metals like cobalt, nickel, and ruthenium have been incorporated in these photocatalysts, alongwith molybdenum based heteropolyacid (HPA) to improve the photocatalytic activity of these materials. Photoreduction of methyl orange under solar radiation was compared with photoreduction in presence of artificial visible light illumination to evaluate their photocatalytic activity. The quantity of methyl orange photoreduced by the cobalt containing photocatalyst was about 2.40 mg/g of TiO₂ under the influence of sunlight as compared to 4.111 mg/g of TiO₂ under artificial visible light illumination. However, the efficiency of the photocatalyst is high as compared to P25 TiO₂ under solar light (0.508 mg/g of TiO₂). The high photocatalytic activity of these materials is due to the synergistic effect of incorporation of transition metals in combination with TiO₂ and HPA supported by the zeolite matrix. These materials are being evaluated for photocatalytic water splitting.     

Debittering and Deacidifying Sour Orange (Citrus aurantium) Juice Using Neutral and Anion Exchange Resins

Juices from four cultivars of sour orange (Citrus aurantium), Seville, Bigaradier, Sour and Bittersweet, were treated with neutral (XAD-16) and weak base anionic exchange (IRA-93) resins. Unidentified fluorescent compounds were removed along with bitter compounds by both resin treatments. Average acidity was reduced from 57–87% using IRA-93 before depletion. Average naringin concentrations were reduced 50–66% in high acid juice and 89% in low acid juice using IRA-93. Under similar conditions 24–30% of the limonin was eliminated using IRA-93 and essentially 100% removed using XAD-16. Sensory acceptance (9-point hedonic scale) improved from 1.6 to 3.0 after IRA-93 resin treatment of a high acid juice. Average acceptance increased from 3.8 to 6.4 after XAD-16 treatment of a low acid juice.     

基于图像原理脐橙分拣技术装置设计的研究

为了实现对脐橙的形状和大小分类快速检测,本文设计了一种简易机械装置与图像识别技术相结合的分类器;并应用MATLAB软件编程技术,实现了对样本图像背景的去除、边缘的提取、形状和大小的判断,从而自动实现脐橙外形与大小的有效分类。     

Inhibitory effect of sour orange (Citrus aurantium) juice on Salmonella Typhimurium and Listeria monocytogenes

The sour orange (Citrus aurantium) juice is commonly used as flavoring and acidifying agent for vegetable salads and appetizers in Turkey. It was aimed to determine the survival and growth pattern of Salmonella Typhimurium and Listeria monocytogenes in sour orange juice. Different concentrations of neutralized and un-neutralized juice samples were inoculated with each of the test microorganisms (∼6 log CFU/mL) separately and then incubated at 4 °C and 37 °C for seven days. It was detected both of the test microorganisms could survive and even grow in neutralized juice samples at 37 °C for two days. However, none of them could survive at the end of seventh day of incubation at 37 °C. Low incubation temperature (+4 °C) increased the survival of the tested microorganisms. Also, it was detected that L. monocytogenes were less resistant to the variable conditions than S. Typhimurium. It was concluded that the antimicrobial effect of sour orange juice mainly depends on the low pH value of the product. However, incubation time and temperature are also effective on the survival of the tested pathogens.     

赣南谢坊萤石矿CaF_2与围岩钙氟特征及成矿意义

对赣南谢坊萤石矿床萤石Ca F2和围岩的钙、氟元素进行了系统检测,分析发现矿井萤石含量与围岩的钙、氟含量具有良好的相关性,表明谢坊萤石的钙氟成矿物源来自矿床围岩.谢坊萤石矿的形成是通过地热水环流汲取围岩Ca,F元素,在合适的断裂空间沉淀析出萤石,形成典型的热液成矿萤石.谢坊萤石矿床围岩的w(Ca)/w(F)大于萤石,显示热液成矿过程中存在Ca的剩余,F元素对成矿起决定作用.     

柑橘-胡萝卜复合果肉饮料的研制

以柑橘、胡萝卜为主要原料,研制一种新型的复合果肉饮料,重点解决产品配方和悬浮稳定性问题。采用单因素实验和正交试验,产品最佳配方为柑橘浆12.5%、胡萝卜浆12.5%、蔗糖11%、柠檬酸0.15%;稳定剂的最佳组合为羧甲基纤维素(Carboxymethyl Cellulose,CMC)0.25%、黄原胶0.15%。在此配方下,产品口感好,稳定效果佳。     

Off-odor Study with γ-Irradiated Orange Juice Using Sensory and Volatile Compound Analyses

ABSTRACT: As irradiation dosage increased from 0 to 0.5, 1.0, 2.0, and 3.0 kGy, total volatile compounds increased by 12%, 15%, 24%, and 54%, respectively. Sensory evaluation showed that irradiated orange juice was significantly different from the nonirradiated control orange juice ( P < 0.05). Dimethyl sulfide, dimethyl disulfide, and 2-butanone were found in irradiated orange juice but not in nonirradiated samples. As irradiation dosage increased, dimethyl sulfide and dimethyl disulfide increased, and off-odor increased. Chemical mechanisms for the formation of dimethyl sulfide and dimethyl disulfide by irradiation are proposed. Dimethyl disulfide, dimethyl sulfide, and possibly other sulfur-containing compounds seem to be partly responsible for the off-odor in irradiated orange juice.     

果汁型橙汁囊胞饮料的悬浮稳定性研究

本文通过提高果汁含量和选用效果良好的复配增稠剂对柑橘为原料制成的果汁型橙汁囊胞饮料的悬浮稳定性进行了研究,同时采用SPME-GC-MS技术对其几种主要香气物质进行了鉴定分析,并研究了其流变特性。实验结果表明,0.2%黄原胶+0.25%果胶,0.15%CMC+0.2%黄原胶+0.1%果胶,0.1%CMC+0.05%黄原胶+0.1%琼脂和0.1%黄原胶+0.1%果胶+0.1%琼脂等4种不同组成的复合稳定剂对果汁型橙汁囊胞饮料的悬浮效果良好;添加了增稠剂的果汁更加稳定,且为非牛顿流体,呈典型的假塑性流体特征,且添加增稠剂对橙汁囊胞饮料中的几种主要香气物质的释放造成了一定影响,不同组成的增稠剂对其影响也不太相同,其中3-蒈烯、d-柠檬烯、β-香叶烯、γ-萜品烯和紫苏醛被检出的含量均出现明显降低,但饮料的表观粘度与香气释放没有直接的关系。