水性聚氨酯涂膜在柑桔贮存保鲜中的应用研究

以常用的保鲜涂膜剂羧甲基壳聚糖、海藻酸钠和自制的水性聚氨酯乳液为涂膜剂,对柑桔进行涂膜保鲜实验,并与未涂膜柑桔作比较,分别测定柑桔失重率、含糖量、Vc含量、呼吸强度随贮存的变化,并观察外观质量。研究发现,用自制水性聚氨酯乳液进行涂膜后柑桔贮存期间的各项参数明显优于未涂膜柑桔和其它浸涂膜的柑桔,从而有效提高了柑桔的商品价值,延长了货架期。     

Recovery of anthocyanins from eggplant peel

Tartaric and malic acid solutions were tested to extract anthocyanins from eggplant peel by a discontinuous process to obtain a natural red colorant. Extraction optimization was carried out, using different solvents, acid concentration, temperature, time of extraction and solvent-to-solid ratio as independent variables. Tartaric acid was more efficient than malic acid in both extraction yield and rate. Comparative tests were carried out using acidified ethanol as solvent. Delphinidin-3-rutinoside was extracted and identified as the major anthocyanin in eggplant peel. Concentration of different extracts from eggplant peel was carried out using EXA-31, a methacrylic food grade resin, the best performing resin to obtain highly concentrated extracts.     

Sensitivity of four foodborne moulds to essential oils from turkish spices,herbs and citrus peel

The antifungal effects of 22 essential oils from Turkish spices, herbs and citrus peel on four foodborne moulds were evaluated for fungistatic and fungicidal activity. The most active oils were wild thyme (Thymus rariflorus L) and thyme (Thymus serpyllum L). Parsley (Penloselinum sativum Hoffin) and savory (Satureja hortensis L) oils were found to be the least active oils. Rhizopus sp displayed the greatest tolerance, and the most sensitive mould was Penicillium chrysogenum. Prolonged incubations reduced the fungistatic and fungicidal effects of oils. It was concluded that some oils may be useful as mould inhibitors at food additive levels.     

柑橘皮在热处理过程中内部温度的时空分布特性

目的：获得柑橘热处理过程中果实内部不同点随时间变化的温度分布规律。方法：从传热的角度研究柑橘皮在热处理过程中的温度变化；提出一种新的方法来计算柑橘皮中的温度传递规律，建立一个新的数学模型来模拟柑橘皮在热处理过程中的温度分布；并重点研究3种柑橘（奉节脐橙、长寿血橙和资阳蜜桔）内部温度场的时空分布。结果：热处理时间随水温的升高呈指数级下降，得到了不同品种柑橘的详细指数关系表达式，并通过数据回归方法提出了柑橘热处理时间与水浴温度之间的函数公式。结论：热处理时间随着水浴温度升高呈指数衰减，过低的水域温度会因传热温差过小导致热处理时间极大延长，增加能源消耗。     

Chemical composition and antimicrobial activities of essential oil from the peel of bingtang sweet orange (Citrus sinensis Osbeck)

The chemical composition of the essential oil obtained from the peel of Bingtang sweet orange ( Citrus sinensis Osbeck) was analysed by gas chromatography and gas chromatography/mass spectrometry (GC/MS). Twenty-seven components were identified. The monoterpenes and sesquiterpene hydrocarbons with 96.03% (w/w) of the total oil were the principal compound groups. Among which, limonene was observed dominant (77.49%), followed by myrcene (6.27%), α-farnesene (3.64%), γ-terpinene (3.34%), α -pinene (1.49%), sabinene (1.29%) and other minor components. Results by disc diffusion method and minimum inhibitory concentration (MIC) determination method showed that the essential oil had a wide spectrum of antimicrobial activities against Staphylococcus aureus , Penicillium chrysogenum , Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae , with their inhibition zones ranging from 14.57 mm to 23.37 mm and the MIC ranging from 4.66 μL mL⁻¹ to 18.75 μL mL⁻¹.     

Fractionation of water insoluble solids and extraction of pectins from residues of juice-extracted satsuma mandarin fruit by wet grinding

The waste biomass residue from satsuma mandarin juice production was extracted by wet-fine grinding and separated by centrifugation into insoluble and soluble fractions. The insoluble material was wet-screened into four fractions and analysed for crude fibre and total hydrolysable sugars. Crude fibre was almost exclusively in fractions containing particles over 50 μm, comprising about 65% of the insoluble material; this could provide a raw material high in crude fibre. The remaining insoluble fraction was almost devoid of crude fibre.
The soluble extract contained up to 63% of the total pectic substances with very similar methoxyl contents and degree of esterification, but double the viscometric molecular weight of a standard citrus pectin. The method provides an alternative to that of hot acid extraction.     

“柠檬烯提取”教学实验的改进

选取提取柠檬烯的最佳原料、改进微型实验装置及提取方法。选择皇帝柑皮为原料,采用超声辅助提取新技术,并进一步结合微型简易水蒸气蒸馏实验装置提取柠檬烯。该方法不仅试样用量少、提取率高、实验效果明显、装置简单、易于操作、缩短了实验时间;而且使学生实践了超声辅助提取的新技术,渗透了微型化学实验的新理念,提高了学生实验的积极性,主动性。"柠檬烯提取"实验的改进方法值得在有机实验教学中推广。     

柑桔果实主要苦味成分的分布及橙汁脱苦技术研究

柑桔果实中主要苦味成分是柚苷和柠碱，本文对它们在主栽柑桔品种果实中的分布情况和利用吸附树脂脱除橙汁苦味的技术进行了研究，并筛选出了优良的国产树脂。