香辛料提取物对白色念珠菌的抑制及工艺优化研究

研究24种香辛料的抑菌作用,并比较其醇提取液的抑菌效果。通过大量的实验测定白色念珠菌抑菌圈,其中肉桂提取液对白色念珠菌抑制作用最佳。然后运用响应面(RSM)分析优化肉桂乙醇提取工艺条件。在单因素实验基础上,以白色念珠菌抑菌圈为指标,研究提取温度、液固比、提取时间及乙醇浓度对白色念珠菌抑菌圈的影响。结果表明,肉桂醇提法最佳提取工艺为提取温度69.24℃,液固比10:1(mL/g),提取时间5h,乙醇浓度95%,在此条件下提取液对念珠菌的抑菌圈是39.46mm。     

油茶粕中茶皂素连续多级逆流水提工艺的建立

为提高油茶粕经济价值,充分利用油茶粕资源,以油茶粕为原料,采用热水连续多级逆流提取油茶粕中的茶皂素,优化了单级提取和连续多级逆流提取工艺参数.结果表明:单级提取的优化条件为提取时间85 min,提取温度80℃,料液比1:16 g/mL,油茶粕提取粒度60～100目.在单级提取基础上,确定连续多级逆流提取的优化提取级数为...     

Extraction of α-tocopherol and γ-oryzanol from rice bran

The aim of this research was to study the effect of operating mode (continuous versus batch+continuous), temperature, pressure and solvent on α-tocopherol and γ-oryzanol extraction from rice bran (Oryza sativa Linn.) and compare the efficiency of three extraction methods: SC-CO₂ extraction, solvent extraction and soxhlet extraction. Three sets of experiments were performed. First, extraction using SC-CO₂ was performed over a range of temperatures and pressures (45-65 °C and at 38 and 48 MPa), and at a CO₂ flow rate of 0.45 mL/min. The results showed that the best conditions for α-tocopherol extraction were 55 °C, 48 MPa in the batch+continuous mode. For γ-oryzanol, the best conditions were 65 °C, 48 MPa and in the continuous mode. In the second set of experiments, solvent extraction using hexane and ethanol at 32 and 55-60 °C was studied. The results showed that none of the solvents could extract α-tocopherol; however, ethanol at 55-60 °C was suitable for γ-oryzanol extraction. Finally, soxhlet extraction experiments using hexane for α-tocopherol and ethanol for γ-oryzanol were also performed. In summary, SC-CO₂ was found to be the best solvent for extracting both α-tocopherol and γ-oryzanol from rice bran, because of its higher yields and extraction rate.     

Hochdruckflüssigchromatographische Untersuchung von Vanille-CO2-Hochdruckextrakten

HPLC has been used for the determination of vanillin,p-hydroxybenzaldehyde, vanillic acid,p-hydroxybenzoic acid, ethyl vanillin, piperonal and coumarin in CO₂ extracts and alcoholic extracts of vanilla beans. Ethyl vanillin, piperonal and coumarin were found in none of the samples. By measuring vanillin,p-hydroxybenzaldehyde, vanillic acid andp-hydroxybenzoic acid a great difference between the amount and the ratio of these main components of the usual alcoholic vanilla extracts and the CO₂ vanilla extracts was shown. The present requirements for vanilla extracts and products containing vanilla extracts refer only to the composition of alcoholic extracts for which, in contrast to CO₂ vanilla extracts, many studies have been published. The critical examination of products containing CO₂ vanilla extracts by using the ratios of vanilla compounds found in the present literature could lead to erroneous complaints. For the purpose of estimating the influence of the extraction solvent on the yield of vanillin, one sample of vanilla beans of each provenance was extracted besides the CO₂ extraction also with the solvents ethanol-water according to the method for a single-fold extract and with the solvents dichloromethane and hexane. In all three cases dichloromethane was found to be the best solvent. Furthermore, the ethanol-water extraction tended to give 6–22% more vanillin than the CO₂ extraction. To achieve unequivocal results, the examination of more samples is necessary.     

Characterization of the volatility of flavor compounds in alcoholic beverages through headspace solid-phase microextraction (HS-SPME) and mathematical modeling

The volatility of flavor compounds (10 distinctive esters commonly found in alcoholic beverages) was characterized using headspace solid-phase microextraction (HS-SPME) analysis combined with mathematical modeling. The impacts of extrinsic factors (extraction time and temperature) and intrinsic parameters (ethanol content and concentration of these flavor compounds) were evaluated on their influences. From extraction profiles, different kinetic behaviors of flavor compounds revealed that volatility is influenced by chemical natures (that is, molecular weight and physicochemical properties). Moreover, volatility was also found to be interrelated with extraction temperature and absorption/adsorption on the fiber's surface. Through mathematical modeling, the kinetic constants of these volatile compounds were computed, and their release profiles were determined. Finally, it was observed that an increase of ethanol (a competitive interference compound to flavor compounds) could decrease the extraction efficiency. Our studies indicated that this approach might be a rapid and practical method that would provide a better understanding of flavor release behavior from alcoholic beverages. PRACTICAL APPLICATION: The proposed approach may provide a simple and fast method in predicting the performance of key aroma esters in different alcoholic beverages. It could also be a practical way in quality control during the production of alcoholic beverage by monitoring key aroma esters.     

三级逆流法提取甜菊糖甙的工艺研究

本实验首先比较研究了晒干、阴干、烘干、微波干燥等几种不同的干燥方式对甜菊叶中甜菊糖甙的影响。结果表明,微波高火干燥的效果最好,只需3min,甜叶菊鲜叶中的水分从76.07% 降到了3.53% 且叶片颜色保持原色,莱鲍迪甙-A(Rebaudioside A,Reb-A)的含量提高了27%,甜菊苷(Stevioside,Ste)的含量提高了22%;然后比较研究了三级逆流连续提取、三罐串联逆流提取及单罐提取甜菊糖甙的提取效率,结果表明这三种方法的提取得率相近(分别为99.9%、99.82% 及99.9%),但三级逆流连续提取的整个过程只需要20min,而其他两种提取方式整个过程至少需要60min,因此,三级逆流连续提取是一种更加适合于工业化大生产的提取方式。     

Study of alcoholic and aqueous extraction of pequi (Caryocar brasiliense Camb.) natural antioxidants and extracts concentration by nanofiltration

Pequi (Caryocar brasilense Camb.) is a typical Brazilian fruit, rich in polyphenols and carotenoids. The present work studied aqueous and alcoholic pequi extraction, in bench scale, evaluating time and temperature variation influence on polyphenols and carotenoids recovery. For the extraction best conditions (25 °C within 1 h for aqueous extract and 40 °C within 24 h for alcoholic extract), a residue reextraction was carried out, which has increased compounds recovery from fruit material. The final extract (a mixture of the first and second extract) was submitted to a concentration step by nanofiltration (in a stirred cell with a temperature of 25 °C and a pressure of 800 kPa). For alcoholic extract, the rejection towards bioactive compounds was small (around 10% for carotenoids and 15% for polyphenols). For aqueous extract, nanofiltration showed a high efficiency to concentrate the polyphenols and carotenoids (with retention coefficient around 100% and 97%, respectively).     

Production of an Alcoholic Beverage by Fermentation of Whey Permeate with Kluyveromyces fragilis II: Aroma Composition

Whey permeate was used for an alcoholic fermentation with Kluyveromyces fragilis (CECT 1123). The aim of the present study was the production of an alcoholic beverage of low alcoholic proof with acceptable concentrations of fusel alcohols. The effects of temperature and agitation on the concentration of volatile compounds was assayed in batch cultures. In addition, the production of acetaldehyde, ethyl acetate and fusel alcohols was studied in continuous culture because of interest in a continuous industrial process. Final concentrations of fusel alcohol were slightly lower at higher temperatures, while the specific production rate increased with temperature. Concentrations were suitable, in all cases, for a beverage. When agitation was assayed, an important increase in fusel alcohol concentrations was found at higher agitations. In continuous culture, the acetaldehyde, ethyl acetate and fusel alcohol concentrations were normal for an alcoholic beverage.     

蓝莓露酒主要成分变化及浸提条件优化

目的 优化蓝莓露酒主要成分变化及浸提条件。方法 以新鲜蓝莓为原料, 用不同纯度的乙醇溶液浸提, 并对浸提过程中溶出的总酚、黄酮、花色苷、总酸、可溶性固形物和维生素C进行动态分析。在多个单因素试验的基础上采用正交试验考察乙醇溶液和蓝莓的比例(A)、浸提用乙醇溶液的纯度(B)、浸提前超声处理时间(C)和浸提时间(D)对蓝莓酒抗氧化能力的影响。结果和结论 最佳的浸提条件为料液比1:1, 浸提用乙醇溶液的乙醇含量60% (v/v), 超声处理时间40 min, 浸提时间为30 d, 在此条件下其DPPH自由基清除率为66.30%。     

微波催陈白酒中型试验的研究

用自制的微波催陈白酒的中型试验装置,在不同的微波处理条件下,对不同品质的白酒进行微波催陈处理。确定了微波催陈白酒的最佳工艺条件条件,分析了不同的微波处理条件对白酒化学成分的影响,对微波催陈白酒的机理也进行了讨论。     

Evaluation of antioxidant activity and total phenols index in persimmon vinegars produced by different processes

The total phenols index (TPI) and antioxidant activity of persimmon vinegars produced by different processes were evaluated. A novel extraction method was designed and optimised for this purpose with respect to the type and concentration of solvent and ultrasonication time. The best extraction conditions found were the use of 80% ethanol and 25 min of ultrasonication. Antioxidant capacity was determined by the oxygen-radical absorbance capacity of fluorescein (ORAC-FL) and 2,2′-diphenyl-1-pycrylhydrazyl (DPPH) free-radical assays. The antioxidant activities were the same in the fruit and the vinegar, except in the ORAC assay, which showed a significant decrease during the acetification process. The results showed that using the wild yeast strain native to the persimmon produced vinegars with higher antioxidant activity than that of an inoculated alcoholic fermentation. Finally, a comparison between our vinegars and other commercial examples was made. The TPI and antioxidant activity values of persimmon vinegars were always higher than those obtained from white and red-wine vinegars. The antioxidant activity and total phenols of the final product indicate that persimmon vinegar is a competitive product in the market.     

Flavour compounds of Lavandula angustifolia L. to use in food manufacturing: Comparison of three different extraction methods

Sixty compounds of Lavandula angustifolia L. cultivated in Friuli Venezia Giulia (North-East Italy) were identified and quantified by GC-MS and GC-FID from essential oils obtained by means of hydrodistillation, and from extracts obtained by supercritical CO₂ extraction (SFE) and ultrasound-assisted extraction (US). Using absolute calibration, a true quantification of 1-8 cineol, camphor, linalool, linalyl acetate and β-caryophyllene was carried out. The best extracts, in terms of amount of isolated compounds, flavour quality and stability were those obtained with SFE. Sonication performed at low amplitude for 5 min offered respect to high amplitude a promising alternative to hydrodistillation as a source of lavender flavouring ready to use for alcoholic beverages or/and confectionery products.     

An Improved and Validated Sample Cleanup Method for Analysis of Ethyl Carbamate in Chinese Liquor

Ethyl carbamate (EC) is a potential human carcinogen widely existing in fermented foods and alcoholic beverages. The solid‐phase extraction (SPE) coupled to gas chromatography mass spectrometry is a widely‐used method to determine EC levels, but the accuracy varies with sample matrix and the effects of operation parameters are rarely examined. In this study, the influence factors involved in EC determination were investigated using Chinese liquor as sample matrix, and the improved method was further applied. Three types of SPE columns, including diatomite, Florisil, and primary‐secondary amine, were compared in extraction efficiency, and the diatomite column exhibited the highest extraction efficiency. The optimal volumes of elution solvents with diatomite column were 15 mL for 3‐mL samples solution loaded. In addition, the alcoholic strength for EC determination should be diluted below 20% (v/v) to avoid the enhancement of matrix‐induced chromatographic response. Moreover, the pH neutralization could help improve EC recovery and peak resolution, reducing interfering effects. Based on these results, the improved method showed that the limit of detection, the limit of quantification, and average recoveries were 1.10 μg/L, 3.65 μg/L, and 93.06%, respectively. To further elucidate the underlying factors related to EC accumulation, partial least square regression analysis was conducted, and the results suggested that EC levels had the closest relationship with alcoholic strength among the remaining precursors.     

Study of ultrasonic wave treatments for accelerating the aging process in a rice alcoholic beverage

This research focussed on the accelerated aging of a rice alcoholic beverage by applying two different levels of ultrasonic power. The rice alcoholic beverage was fermented with Saccharomyces sake. The control treatment was aged for one year in fired clay containers (standard aging) while two other treatments simulated aging by using 20 kHz and 1.6 MHz ultrasonic waves, respectively (accelerated aging). Comparisons were made of alcohol content, titratable acidity value, gas chromatography measurements of volatile aroma compounds, sensory evaluation and time of aging. Results showed that the 20 kHz treatment influences rice alcoholic beverage aging better than the 1.6 MHz treatment. The 20 kHz ultrasonic wave treatment has potential as a good alternative method for aging the alcoholic beverage. Further studies are needed to elucidate the best power range of ultrasonic waves for aging alcoholic beverages made of various materials.     

固定化酵母连续发酵酒精染菌问题的探讨

提出了固定化活酵母连续发酵生产过程中杂菌感染的原因及预防,并重点探讨了在生产中染菌的挽救措施。     

Effect of different extraction and precipitation methods on yield and quality of pectin

An experimental study has been conducted to determine the combined effects of different extraction conditions and precipitation method on the yield and quality of high methoxyl pectin from lemon peels. Pectin was extracted using different mineral acids (HCl, HNO₃ and H₂SO₄) at four concentration levels (0.025; 0.05; 0.1 and 0.2  m ), at 70 °C for 4 h. The soluble pectin was precipitated by iso-propanol or by an aluminium sulphate, Al₂(SO₄)₃, solution at pH 4. The extraction with HCl and HNO₃, at the highest concentrations investigated, followed by aluminium precipitation led to the best results in terms of yield (22–25%), quality and gelling power of pectin with a remarkable decrease of alcohol consumption as compared to the alcoholic precipitation under the same extracting conditions.     

Method for the simultaneous assay of diacetyl and acetoin in the presence of alpha-acetolactate: application in determining the kinetic parameters for the decomposition of alpha-acetolactate

A simultaneous assay method for diacetyl and acetoin was developed to investigate the formation of diacetyl during the brewing of alcoholic beverages. A GC-MS analysis after the extraction from neutralized sample by ethyl acetate gave accurate assay results. The detection limit was below 0.1 mg/l and the assay was quantitative from 0.1 to 100 mg/l for both compounds. Unlike other methods, the assay results were unaffected by the presence of alpha-acetolactate (up to 26 mg/l), which easily decomposes to diacetyl or acetoin, because the extraction condition prevents the decomposition and extraction of this acidic compound. Since our assay is compatible with samples that contain alpha-acetolactate, the kinetic parameters for decomposition of alpha-acetolactate to diacetyl and acetoin were determined. The decomposition rate constants were affected by the ethanol concentration. Overall kinetics for the decomposition of alpha-acetolactate was formulated as a function of ethanol concentration, pH and temperature. The kinetics can be applied to alcoholic beverages such as sake.     

Content of biogenic amines and polyamines in beers from the Czech Republic

Altogether 114 samples of alcoholic and non‐alcoholic bottled beer produced in 28 breweries in the Czech Republic were monitored for levels of biogenic amines (BA) and polyamines (PA). The beers were analysed immediately after purchase and then at the end of the best‐before period (storage temperature 8 ± 1 °C). The concentrations of histamine, phenylethylamine and tryptamine in the studied samples were very low (mostly under 30 mg L^?1). The studied PA spermine and spermidine also occurred in small amounts. Nevertheless, the levels of tyramine, putrescine and cadaverine reached significant values, especially in alcoholic beers. In almost 25% of the tested samples of alcoholic beers (at the end of the best‐before period), the total amount of all the monitored BA and PA exceeded the ‘healthy’ level of 100 mg L^?1, which is considered toxicologically significant, especially in alcoholic beverages. Copyright © 2012 The Institute of Brewing & Distilling     

低温连续相变萃取灵芝活性成分的工艺优化

本研究利用低温连续相变萃取工艺提取灵芝活性成分,以灵芝提取固形物、总糖、总三萜得率为主要指标,研究提取温度、提取时间、提取溶剂、溶剂浓度等因素对低温连续相变萃取灵芝活性成分的影响,通过正交实验确定最佳低温连续相变醇提灵芝活性成分的最佳工艺条件,并对该最佳工艺水提成分的总糖分子量情况分布进行GPC(凝胶渗透色谱)分析.实...     

The influence of skin contact during alcoholic fermentation on the aroma composition of Ribolla Gialla and Malvasia Istriana Vitis vinifera (L.) grape wines

Grapes from the Vitis vinifera (L.) varieties Ribolla Gialla and Malvasia Istriana were subjected to two skin contact procedures: pomace maceration and whole berry maceration during alcoholic fermentation. Wine free volatile compounds were determined using two extraction techniques coupled to GC; odour activity values were calculated and compared to control wines without skin contact. The highest concentrations of esters and relative fruity impacts were determined in the control wines for both varieties. Pomace maceration was found to be an effective procedure for the extraction of varietal aroma compounds like terpenes, but only in the Malvasia Istriana was their higher impact on floral odour determined. Pomace maceration resulted in higher total phenol and methanol content. Whole berry maceration was less efficient in terpene extraction, and its impact on general wine composition was not so radical. Control wines were chosen as preferred wines for odour and overall impression.