PILOT PLANT EXTRACTION OF HOPS WITH LIQUID CARBON DIOXIDE AND THE USE OF THESE EXTRACTS IN PILOT AND PRODUCTION SCALE BREWINGa

Several varieties of hop have been satisfactorily extracted using liquid carbon dioxide in a plant operating on the 1 kg scale. The extracts have been used in small scale (0·6 and 16 hl) and production scale (700–800 hl) brewing trials where both ales and lagers were produced. All beers were of sound quality and could not be distinguished organoleptically from controls brewed with either hops or commercial hop extracts.     

酒花收获和贮藏的质量管理

酒花贮藏指数通常用来表示酒花的新鲜度,便于酿造者精确地了解酒花在采摘,加工以及贮藏过程中是否处理得当。对2003～2005年期间4个斯洛文尼亚的酒花品种和1个国外的酒花品种的延后采摘以及不同贮藏条件下酒花的新鲜度进行了测试。酒花采摘后(技术成熟)立刻采用ASBCH-6,12方法分析酒花的贮藏指数(HSI),EBC7.4方法分析酒花的α-酸。技术成熟后采摘的样品分别贮藏在0℃和20℃,并分别在1个月,2个月,3个月和6个月后进行分析。为了了解酒花在自然生理成熟期间α-酸和HSI的变化,每一品种留30株延后采摘,然后再以同样的时间间隔采摘和分析,11月底采摘最后的酒花样品。结果表明,自然生理成熟酒花的氧化进程低于酒花在20℃贮藏1个月,2个月,3个月和6个月的氧化进程。生理成熟后采摘的酒花的贮藏指数如果以A275/A325定义,则仍然具有新鲜酒花的质量。     

Antiangiogenetic Effects of 4 Varieties of Grapes In Vitro

Abstract: The purpose of this study was to investigate the inhibitory effects of grapes on the human umbilical vein endothelial (HUVE) cells’ capillary tube formation and matrix metalloproteinase-2 (MMP-2) expression secreted into the medium. Four different grape varieties (Concord, Niagara, Chardonnay, and Pinot Noir) were extracted using 80% acetone and the extracts were stored at −80 °C. The total amount of phenolics and flavonoids for each of the 4 grape varieties were determined by spectrophotometry. Grape extracts were co-cultured with HUVE cells on Matrigel and inhibitory effects on tube formation were observed under a microscope. The inhibitory effects of grape extracts on MMP-2 expression were examined by zymogram. All 4 grape varieties inhibited the tube formation of HUVE cells in a dose-dependent manner on Matrigel. Except for Chardonnay, the other 3 grape varieties completely inhibited secretion of MMP-2 at 20 mg/mL. There was a significant positive relationship between the total phenolics and flavonoids and antiangiogenetic activities. The grapes tested have the potential to inhibit angiogenesis mainly by their phenolics and flavonoids contents, which partly contribute to their cancer chemopreventive efficacy.     

AUTOMATED REPORTING ON THE QUALITY OF HOPS AND HOP PRODUCTS

The quality of a hop variety or a hop product can readily be assessed by a fully automated sequence of selective extraction, fractionation and quantitative analysis. To illustrate the elegance of the method, nine hop varieties and three hop extracts were compared with respect to the content of important marker compounds in the hop oils and of the hop acids. Supercritical fluid extraction at different densities of carbon dioxide was applied to extract selectively, the hop oils and the hop acids, respectively. The hop oils were further fractionated into an apolar and a polar fraction by solid phase extraction and consecutive elution with n-hexane and ethyl acetate. Separation and identification were achieved by capillary gas chromatography coupled to mass spectrometry. Myrcene, β;-caryophyllene, α;-humulene and β;-farnesene in the apolar fraction, linalool, undecan-2-one, tridecan-2-one and humuladienone in the polar fraction were selected for quantitative evaluation of the respective hop oils. Sulphur-containing compounds were revealed by capillary gas chromatography using sulphur-selective atomic emission detection. Complete separation and quantification of all hop α;-acids and β;-acids was effected by microemulsion electrokinetic chromatography coupled to diode array detection .     

啤酒花废弃枝叶多酚、黄酮含量与抗氧化活性的相关性分析

采用不同极性溶剂对新疆种植的札一和马可波罗啤酒花废弃枝叶的乙醇提取物进行不同极性部位的分 离,以羟自由基、1,1-二苯基-2-三硝基苯肼自由基、β-胡萝卜素-亚油酸及磷钼酸4 个不同的抗氧化活性评价体系 对获得的各提取物的抗氧化活性进行比较性研究,并与提取物中多酚、黄酮含量进行相关性分析。结果表明, 乙醇提取物及各极性部位均具有一定的抗氧化性。其中,乙酸乙酯提取物中的多酚和黄酮的含量均最高,其在主 枝、侧枝和叶子的含量范围分别为5.80～34.20 mg/g和2.00～18.00 mg/g;水相中最低,上述各物质的含量范围仅为 0.73～11.05 mg/g和0.06～5.74 mg/g。相关性分析表明,啤酒花主枝、侧枝和叶子抗氧化活性与其多酚、黄酮含量 具有显著的相关关系（P＜0.05）。     

Antioxidant Characteristics of Hops and Hop Products

The method based on the reaction of stable DPPH radical proved to be the best for the determination of antioxidant characteristics of hops and hop products. Antioxidant activity is expressed as the rate of decline in absorbance of the reaction environment and assessed in relative percents. Differences in the values of antioxidant activity were determined in Czech and foreign hop varieties. The highest antioxidant activities in the scope of 70 to 80% rel. were measured in Saaz and Spalter Select. Antioxidant activity in most of the varieties moved in the scope of 40 to 60% rel. A part of antioxidant activity of hops is irreversibly lost in the course of drying. The loss does not usually exceed 5% of the original RA_DPPH value. Drying also resulted in a decrease of polyphenol compound contents. Drying in belt and chamber kilns is comparable from the point of view of preserving hop antioxidant properties. Results of determination of antioxidant activity in hot water extracts of raw hops and ground hops were comparable and statistically non‐significant. The same held true for pelletizing of ground hops. The antioxidant activity of raw hops declined in the course of long‐term storage in dependence on storage temperature. Storage temperature had no effect on the antioxidant activity of the hop pellets packed in a multi‐layer foil without air access.     

Determination of the botanical origin of hops (Humulus lupulus L.) using different analytical techniques in combination with statistical methods

Beer flavour and aroma depend mostly on the hop variety used in the brewing process. For this reason it is of crucial importance for brewers to be certain about the botanical origin of the hop variety. Metabolic fingerprinting is one of the approaches that can be used for determination of the botanical origin of many agricultural and food products. The aim of the current work was to differentiate between the five most important hop varieties in Slovenia. Gas chromatography, high‐performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy were carried out in combination with three different chemometric methods – principal component analysis, regularized discriminant analysis and hierarchical clustering – on 121 hop samples. The chemometric classification of the hop varieties was obtained with nearly 100% success. The best results were obtained with GC and HPLC data, within one year of harvesting. Copyright © 2016 The Institute of Brewing & Distilling     

IDENTIFICATION OF VOLATILE DATE COMPONENTS AND USE OF MULTIVARIATE ANALYSIS TO DISTINGUISH DATE VARIETIES1

Pentane extracts which possessed strong date-like aromas were obtained from three date varieties and analyzed by gas chromatography-mass spectrometry. Thirty-six volatile components were identified and only six of these had been found earlier in dates. Many of these components possessed aromas and flavors which could contribute to the sensory characteristics of dates, suggesting that a combination of volatile components is responsible for the desirable flavor of dates. Headspace gas chromatographic analysis of fresh dates from each of the three varieties combined with multivariate analysis involving eleven of the known constituents was used to distinguish differences among the varieties.     

STABILITY OF ESSENTIAL OIL OF HOPS

The stability of hop essential oil in beers, in hops and in aqueous emulsions has been investigated. Hop character of beers treated with hop oil emulsion has stability on pasteurization and storage similar to that of dry hopped beers. When bottled with high levels of headspace air, beers lose hop character. Beers dry-hopped with stored hops or with hops damaged during pelleting tend to develop sulphury flavours. However, hop oil emulsions prepared from such hops give rise to a sound hop character in beer. Hop oil emulsion produced by the new process shows good stability physically, chemically and biologically, particularly when mechanically homogenized and stored under an inert atmosphere. The extent of any chemical alteration due to contact with air may be estimated spectrophotometrically.     

PRODUCTION-SCALE APPARATUS FOR THE INJECTION OF HOP EXTRACTS INTO BEER USING LIQUID CARBON DIOXIDE

Extracts of hops made with liquid carbon dioxide can be substituted for dry hops to introduce the flavour of hop oils into beer. Apparatus has been devised so that such extracts can be redissolved in liquid carbon dioxide and then metered into beer. Successful trials have been carried out on the commercial scale.     

Effect of canning and storage on the chemical composition and organoleptic quality of juices of different varieties of oranges grown in Lebanon

Juice from five different varieties of oranges grown in Lebanon was canned according to commercial practices and stored at room temperature. At weekly intervals for seven weeks, chemical analyses for ascorbic acid, total acidity, total soluble solids, nitrogen, ash, total lipids, total solids, essential oils and flavonoids were performed on each sample. The fresh juice from the Blood and Washington Navel varieties compared favourably in chemical composition with a concentrated frozen product from the U.S.A.; the juice from Blood withstood canning and storage better than all other varieties tested. In all samples, there was a significant decrease in the levels of ascorbic acid and of essential oils during storage. Statistical analysis of organoleptic evaluations showed that, in general, blends of two or three different varieties were preferred to the juice from a single variety.     

STABILITY OF AQUEOUS EMULSIONS OF THE ESSENTIAL OIL OF HOPS

Hop oil emulsions prepared from different varieties of hops have been found to exhibit enhanced physical stability on the addition of blends of the emulsifiers Span 20/Tween 80 or Span 60/Tween 60. Examination of the particle size and volume distributions of an emulsion by use of a Coulter Counter was found to be an excellent method of monitoring its stability. An indication as to the relative efficiency of emulsifiers can be obtained from Coulter Counter measurements on hop oil emulsions after storage for 4 days. The use of an ultracentrifuge provies a rapid means of testing emulsion stability and hence the effectiveness of emulsion stabilizers.     

The phenolic content and antioxidant activity of the aqueous and hydroalcoholic extracts of hops and their pellets

The goal of this study was to investigate how three commonly used systems (water, 50% methanol and 50% ethanol) affected the yields of phenolic substances and the antioxidant capacity of extracts prepared from hops (cv Magnum and Marynka) and their pellets (T90 and T45). The total phenolic (TPC) and total flavonoid contents (TFC), as well as antioxidant activity (ABTS^+? scavenging, reducing power and metal chelating activity) of the hydroalcoholic extracts were found to be significantly higher than those of aqueous extracts. Extraction using 50% ethanol produced the highest yield of flavonoids. In turn, aqueous–methanol extracts were a better source of chlorogenic acid. No significant differences in terms of TPC and TFC were found between extracts prepared from hops and their pellets when water was used for extraction. Aqueous–ethanol extracts of T45 pellets, regardless of the hop variety, exhibited higher TFC compared with those of T90 pellets. For aqueous and aqueous–methanol extracts, such a tendency was not observed. Extraction with water revealed that cv Marynka hops and pellets had higher TPC than those of cv Magnum, which resulted in their better antioxidant potential. Hydroalcoholic extracts, regardless of the type of alcohol and hop product, did not differ significantly in terms of antioxidant activities. Copyright © 2013 The Institute of Brewing & Distilling     

Patterns of Peroxidase in Ripening Mango (Mangifera indica, L.) Fruits

Chemical and biochemical changes in Lippens and Smith mango cultivars stored at 12°C and 85–90% RH were studied. The observed chemical changes were similar in both varieties. Peroxidase (POD) activity increased in pulp tissues up to the climacteric stage of ripening. In a parallel way, the quantity of extractable proteins decreased from preclimacteric to ripe or senescent fruits. Polyacrylamide gel electrophoresis of the extracts from Smith mangoes revealed three isoenzymes of POD which moved towards the anode at pH 8.3. The isoenzyme pattern of POD of Lippens mango extracts was quite different, showing four faster moving bands in addition to the above mentioned three characteristic bands of Smith mango fruits. Relative activity of the different isoenzymes changed during ripening may provide insight into the ripening process.     

不同贮藏蔬菜中亚硝酸盐变化的研究

本研究以大白菜、甘蓝、白萝卜为试验材料,研究了室温、低温、腌制三种贮藏蔬菜中亚硝酸盐含量的变化及其形成的机理。结果表明:室温、腌制两种贮藏方法的初期都出现“亚硝峰”。形成“亚硝峰”的原因依贮藏方法而异,室温贮藏蔬菜中“亚硝峰”的形成是由于采摘后菜体内硝酸还原酶的活性增强导致蔬菜内硝酸盐还原成亚硝酸盐;腌制贮藏蔬菜中“亚硝峰”的形成是由于发酵过程中杂菌所致。腌制菜中“亚硝峰”的峰值大大高于室温贮藏,并超过FAO/WUO规定的ADI值,腌制后期亚硝酸盐含量在安全食用范围。室温、低温贮藏蔬菜中亚硝酸盐含量的最高值小于ADI值,可以放心食用。     

PREPARATION OF HOP EXTRACTS WITHOUT USING ORGANIC SOLVENTS

Extraction of hops with liquid carbon dioxide at ambient temperature provides an attractive means of producing hop extracts which are rich in α-acids and free from hard resins, polyphenols, pigments and residual organic solvents. The resulting yellow extracts give beer with a clean bitter flavour when they are added during wort boiling. Manufacturing costs using the process are likely to be substantially less than in a conventional hop extraction plant.     

STORAGE DETERIORATION OF FREEZE-DRIED AVOCADO PUREE AND GUACAMOLE

SUMMARY— The effect of storage temperature, time and atmosphere on the chemical and organo-leptic characteristics of freeze-dried avocado puree and guacamole was studied using Waldin, Lula and Booth-8 varieties of avocado. Oxidation rates were slower at 21°C than at 38°% storage and nitrogen atmospheres reduced the peroxide formation. Significant differences existed in oxidation rates between avocado varieties and also between guacamole and avocado puree in some instances. A logarithmic relationship was found between peroxide values and storage time in air. Guacamole made with Lula avocados was unacceptable after 3 weeks of storage in air at 38°C. Samples stored in nitrogen at 38°C ware unacceptable at the end of 7 weeks. Samples stored in air at 21°Cwere acceptable after 12 weeks and those stored in nitrogen at 2l°C after 15 weeks. A commercial BHA antioxidant reduced the oxidation rate of Lula puree but did not increase shelf life in air storage at 38°C. Peroxide values were of no use in predicting acceptability, since organoleptic deterioration could occur without any peroxide increase.     

Amylase isozymes of oats (Avena sativa L.)

Amylase isozymes were studied in six varieties of Avena sativa L. using agar gel electrophoresis. Three distinct zymograms were detected in aqueous extracts of endosperm of 4 to 5-day old seedlings. No intravarietal variation was observed. These results indicate that amylase zymograms may be useful markers for helping in the identification of oat varieties. Using the varieties Maris Tabard and Maris Titan it was found that all the isozymes in 4 to 5-day old seedlings, except one, had the properties of α-amylase. The zymograms of extracts from ungerminated grains of these two varieties, although apparently identical to those of 4 to 5-day old seedlings, differed in that all the α-isozymes in the former were found to be heat labile whereas in the latter they were heat stable.     

BUTTER STABILITY AS AFFECTED BY EXTRACTS OF SAGE, ROSEMARY AND OREGANO

Effects of methanolic extracts of sage ( Salvia fruticosa L.), rosemary ( Rosmarinus officinalis L.) and oregano ( Origanum vulgare L.) on butter stability were investigated. All extracts were individually added to butter at 0.02 or 0.05%. For comparison, 0.02% butylated hydroxyanisole (BHA) and control group were also prepared and tested. The samples were stored at 25 or 5C. The peroxide value, free fatty acids and thiobarbituric acid value were determined at regular intervals for all samples. Spice extracts and their combinations exhibited a better effect than that of BHA in stabilizing butter against oxidation. The most effective extract was that of sage. The extracts significantly stabilized butter (P<0.05). Butter samples stored at 5C were more stable (P<0.05) than those kept at 25C.