Cholesterol reduction in camel hump fat using ��-cyclodextrin

??-Cyclodextrin (??-CD) was used for removing cholesterol from fatty tissues such as lard, milk fat. This investigation was carried out to study optimum conditions of different factors (??-CD concentration, stirring temperature, stirring time, stirring rate and ratio of hump camel fat to water for reduction of cholesterol in hump camel fat by application of ??-CD and resulting changes in cholesterol reducing camel hump fat). ??-CD concentration at 1?C10% provided about 88.89?C95.3% removal of cholesterol when mixed at 40°C for 91?h. Among other factors, mixing time (0.5?C2?h) did not significantly affect cholesterol reduction. Removal was enhanced with increasing stirring rate to 800?rpm and centrifugal forces up to 5,000×g (95.5%) but decreased thereafter. The obtained results showed that the optimum conditions for the process were addition of 7% ??-CD, 40°C mixing temperature, 1?h of mixing time, the ratio of camel hump fat to water 1:1, and stirring rate 800?rpm and centrifugation at 5,000×g. The acid value of ??-CD treated camel hump fat was significantly decreased due to removal of free fatty acid. The peroxide value of ??-CD treated camel hump fat was slightly increased. No significant differences were noted in the fatty acids composition between treated with ??-CD and untreated camel hump fat.     

Cholesterol reduction in camel hump fat using β-cyclodextrin

β-Cyclodextrin (β-CD) was used for removing cholesterol from fatty tissues such as lard, milk fat. This investigation was carried out to study optimum conditions of different factors (β-CD concentration, stirring temperature, stirring time, stirring rate and ratio of hump camel fat to water for reduction of cholesterol in hump camel fat by application of β-CD and resulting changes in cholesterol reducing camel hump fat). β-CD concentration at 1–10% provided about 88.89–95.3% removal of cholesterol when mixed at 40°C for 91 h. Among other factors, mixing time (0.5–2 h) did not significantly affect cholesterol reduction. Removal was enhanced with increasing stirring rate to 800 rpm and centrifugal forces up to 5,000×g (95.5%) but decreased thereafter. The obtained results showed that the optimum conditions for the process were addition of 7% β-CD, 40°C mixing temperature, 1 h of mixing time, the ratio of camel hump fat to water 1:1, and stirring rate 800 rpm and centrifugation at 5,000×g. The acid value of β-CD treated camel hump fat was significantly decreased due to removal of free fatty acid. The peroxide value of β-CD treated camel hump fat was slightly increased. No significant differences were noted in the fatty acids composition between treated with β-CD and untreated camel hump fat.     

Optimizing cholesterol removal from cream using β-cyclodextrin cross-linked with adipic acid

The present study was carried out to optimize the different conditions for cross-linked β-cyclodextrin (β-CD) using adipic acid on cholesterol removal in cream. Different factors were β-CD concentration, mixing temperature, mixing time and mixing speed. Cross-linked β-CD was prepared with adipic acid. When the cream was treated with 10% cross-linked β-CD, cholesterol removal was the highest at 90.7%, which was not significantly different from treatments with 15% and 20% cross-linked β-CD. Cholesterol removal was significantly influenced by mixing temperature, mixing time and mixing speed. After cholesterol removal from cream, the used cross-linked β-CD was washed for cholesterol dissociation and reused. For recycling study, the cholesterol removal in first trial was 91.5%, which was mostly same as that using new cross-linked β-CD. However, after 10 repeated trials using the same sample, only 83.4% of the cholesterol was removed from cream. Therefore, the present study indicated that the optimum conditions for cholesterol removal using cross-linked β-CD were 10%β-CD addition, 30 min mixing with 1400 r.p.m. speed at 40°C with over 90% cholesterol removal. In addition, recycled β-CD cross-linked with adipic acid showed a similarly high recycling efficiency to unused β-CD of about 90% up to the seventh trial.     

Effects of gas flow rate, inlet concentration and temperature on biofiltration of volatile organic compounds in a peat-packed biofilter

The effects of incoming gas concentration, empty bed residence time (EBRT), and column temperature on the removal efficiency of volatile organic compounds (isoprene, dimethyl sulfide, chloroform, benzene, trichloroethylene, toluene, m-xylene, o-xylene and styrene) were studied for 101 d in a biofilter comprising two glass columns (I.D. 5.0 cm x height 62 cm) packed with peat. At an EBRT of 3 min the removal efficiency increased up to 90% 34 d after start up at both 25 degrees C and 45 degrees C when the incoming gas concentration was raised stepwise to 65 g.m(-3). When the incoming gas concentration increased to 83 g.m(-3), the removal efficiency was 93% at 25 degrees C, but dropped to 74% at 45 degrees C. At an incoming gas concentration of 92 g.m(-3) and an EBRT of 1.5 min, the removal efficiencies were 91% and 94% at 25 degrees C and 32 degrees C, respectively. However, at 1 min of EBRT, the removal efficiencies decreased to 68% and 81% at 25 degrees C and 32 degrees C, respectively. The removal rate per unit time and per unit volume of the biofilter was proportional to the incoming gas rate up to 3483 g VOC.m(-3).h(-1). Further increase of the incoming gas rate lowered the removal rate as compared to that predicted by the proportionality. The maximum removal rate was 3977 g.m(-3).h(-1) at 32 degrees C. At an EBRT of 1.5 min, the removal efficiency was highest for isoprene (93%), and lowest for chloroform (84%). Aromatic compounds (benzene, toluene, and xylene) were removed by 93-94%. The cell concentration increased 100-fold from the initial value, and reached 1.12 x 10(8) cells.(g of dry peat)(-1). At 32 degrees C, 67% of the incoming VOC was removed in the first quarter of the column.     

Functional properties of cholesterol-removed whipping cream treated by beta-cyclodextrin

The present study was carried out to examine the changes in functional properties of cholesterol-removed whipping cream by beta-cyclodextrin (beta-CD) treatment. The cholesterol removal rate reached over 90% in cream before whipping in all conditions (different stirring time and speed) applied. The apparent viscosity of beta-CD treated cream after whipping increased with increased stirring time and speed. Comparatively, the overrun percentage reached to 150%, and foam instability was measured as 2.5 ml deformed cream with lower stirring time (10 min) and speed (400 rpm). The thiobarbituric acid value of cholesterol-removed whipping cream increased from 0.08 to 0.14 stored at 4 degrees C during 4 wk; however, no difference was found compared with that of control. Above results indicated that beta-CD treatment process for cholesterol removal did not show a profound adverse effect on functional properties of cream after whipping.     

Use of β-cyclodextrin to decrease the level of cholesterol in milk fat

This study was carried out to determine optimum conditions (β-cyclodextrin concentration, mixing time, and holding time) for cholesterol removal from pasteurized nonhomogenized milk at 4°C on a commercial scale by adding β-cyclodextrin in a specially designed bulk mixer tank. The β-cyclodextrin (0.4, 0.6, 0.8, and 1.0%) removed from 65.42 to 95.31% of cholesterol at 4°C in 20 min. Treatment of milk with 0.8 and 1.0% (wt/vol) β-cyclodextrin was no better than treatment with 0.6% β-cyclodextrin. Maximum cholesterol removal was seen with 6 h of treatment. The β-cyclodextrin cholesterol complex was precipitated from milk during 20 min without stirring at 4°C and removed by centrifugation. After separating the milk, approximately 0.35% of residual β-cyclodextrin remained in the skim fraction and 0.1% in the cream from milk treated with 0.6% β-cyclodextrin. The rest of the β-cyclodextrin was complexed with the cholesterol and eliminated via the discharger of the separator. Individual fatty acid and triglyceride compositions did not differ between control milk and milk treated with 0.6% β-cyclodextrin.     

Optimisation of cross‐linking β‐cyclodextrin and its recycling efficiency for cholesterol removal in milk and cream

This study was carried out to investigate the optimum conditions of cross‐linking β‐cyclodextrin (β‐CD) and recycling for cholesterol removal in milk and cream. The cross‐linked β‐CD was prepared with a 15% adipic acid solution, and the water solubility of the β‐CD was measured for the optimum conditions based on mixing temperature, mixing time, cross‐linking temperature, cross‐linking reaction time and cooling time. In the results of this study, optimum conditions were 80 °C mixing temperature, 2 h mixing time, 60 °C cross‐linking temperature, 24 h cross‐linking reaction time and 48 h cooling time. After determining the optimum conditions, the recyclable yields of the cross‐linked β‐CD ranged from 90.01% to 55.17% in six recyclings and the percentage of cholesterol removal by 15% cross‐linked β‐CD was over 90% until eighth recycling. On the basis of the results, this study suggests that 15% adipic acid‐added cross‐linked β‐CD maximised recyclable yield and that cholesterol removal was improved during recycling.     

Selective retension of active cells employing low centrifugal force at the medium change during suspension culture of Chinese hamster ovary cells producing tPA

The effect of centrifugal force applied for cell separation at the medium change on the growth, metabolism and tissue plasminogen activator (tPA) productivity of Chinese hamster ovary (CHO) cells suspension culture was investigated. The viability of the precipitated cells increased exponentially as the centrifugal force decreased. However, the cell recovery was lower than 91% when centrifugal forces applied for 5 min was less than 67 x g. In cultures incubated for 474 h with 7 medium changes employing centrifugal forces ranging from 67 to 364 x g, a centrifugal force lower than 119 x g resulted in higher specific rates of growth, glucose consumption, and lactate and tPA production during the whole culture period. On the other hand, daily centrifugation at 67 to 537 x g without discarding the supernatant had no effect on the specific rates. The cultures inoculated with cells precipitated at a centrifugal force of 67 x g showed apparently higher specific rates of metabolism compared to those inoculated with cells in the supernatant. The cells in the supernatant and the precipitate obtained following centrifugation at 67 x g have average diameters of 15.5 and 17.4 microm, respectively. The intracellular contents of amino acids, especially nonessential amino acids, of the precipitated cells were markedly higher than those of the cells in the supernatant. These results indicate that large cells with high amino acid content and metabolic activity were selectively retained in the culture by means of centrifugation at low forces such as 67 x g. Consequently, application of a low centrifugal force is recommended for medium change in order to maintain higher specific productivity of suspended mammalian cells in perfusion culture.     

壳聚糖改性膨润土处理味精废水的研究

我国膨润土资源丰富,其吸附性能较好,用壳聚糖作为改性剂,对天然钙基膨润土进行有机改性,并对其进行比表面积测定,电镜扫描及红外光谱分析等性能表征,综合表征结果可知,壳聚糖的加入,并没有改变膨润土的基本框架,只是负载到其表面,提高了吸附性能。用壳聚糖改性膨润土处理高浓度味精废水,考察其最佳处理条件。结果表明:投土量为14g/L,pH值为8,搅拌时间30min,离心时间10min为处理味精废水的最佳条件。此条件下改性膨润土对味精废水中CODcr的去除率可达60%,NH3-N的去除率达37%。     

柠檬渣澄清甘蔗汁的研究

为了提高甘蔗汁的透光率,研究了用改性柠檬渣对甘蔗汁进行澄清。利用单因素考察改性柠檬渣的用量、振荡时间、振荡温度和振荡速度对甘蔗汁透光率的影响。并在此基础上设计了L9(34)振荡正交实验和离心实验。实验结果表明加入改性后的柠檬渣能明显提高甘蔗汁的透光率;最优振荡组合:振荡时间为70 min,振荡温度为30℃,振荡速度为100 r/min,40 m L甘蔗原汁中加入改性柠檬渣用量为0.1 g;最优离心组合为:离心机转速为7000 r/min,离心时间为15 min,离心次数为1。在此工艺条件下的甘蔗汁的透光率可达到94.7%。      

Validation of a manufacturing process for fermented, semidry Turkish soudjouk to control Escherichia coli O157:H7

Two soudjouk batters were prepared from ground beef (20% fat) and nonmeat ingredients and inoculated with a five-strain mixture of Escherichia coli O157:H7 to yield an initial inoculum of 7.65 log10 CFU/g. One batter contained a commercial-starter culture mixture (approximately 8.0 log10 CFU/g) and dextrose (1.5%), while the other batter relied upon a natural fermentation with no added carbohydrate. Following mixing, sausage batters were held at 4 degrees C for 24 h prior to stuffing into natural beef round casings. Stuffed soudjouk sticks were fermented and dried at 24 degrees C with 90 to 95% relative humidity (RH) for 3 days and then at 22 degrees C with 80 to 85% RH until achieving a product moisture level of approximately 40%. After fermentation and drying with an airflow of 1 to 1.5 m/s, the sticks were either not cooked or cooked to an instantaneous internal temperature of 54.4 degrees C (130 degrees F) and held for 0, 30, or 60 min. The sticks were then vacuum packaged and stored at either 4 or 21 degrees C. For each of three trials, three sticks for each treatment/batter were analyzed for numbers of E. coli O157:H7 after inoculation, after fermentation, after cooking, and after storage for 7, 14, 21, and 28 days. Reductions in numbers of E. coli O157:H7 after fermentation and drying for sticks fermented by the starter culture (pH 4.6) and for sticks naturally fermented (pH 5.5) were 1.96 and 0.28 log10 CFU/g, respectively. However, cooking soudjouk sticks produced with a starter culture and holding at 54.4 degrees C for 0, 30, or 60 min reduced pathogen numbers from an initial level after fermentation and drying of 5.69 log10 CFU/g to below a detectable level by either direct plating (<1.0 log10 CFU/g) or by enrichment. In contrast, cooking soudjouk sticks produced without an added starter culture decreased pathogen numbers from an initial level after fermentation and drying of 7.37 to 5.65 log10 CFU/g (54.4 degrees C, no hold), 5.04 log10 CFU/g (54.4 degrees C, 30 min hold), and 4.67 log10 CFU/g (54.4 degrees C, 60 min hold). In general, numbers of E. coli O157:H7 within both groups of soudjouk sticks decreased faster during storage at 21 degrees C compared to 4 degrees C. After 28 days of storage, total reductions in pathogen numbers in soudjouk sticks produced using a starter culture but that were not subsequently cooked were 7.65 and 3.93 log10 CFU/g at 21 and 4 degrees C, respectively. For naturally fermented soudjouk, total reductions varied from 4.47 to 0.45 log10 CFU/g, depending on the cooking time and storage temperature. These data provide guidelines for manufacturers of dry sausage of ethnic origin, including soudjouk, to assess the safety of their processes for control of E. coli O157:H7.     

提高双歧杆菌在离心过程中活菌收得率的研究

菌体细胞的分离技术是制备双歧杆菌冻干制剂重要的中间工艺环节。本文建立了研究离心过程国活菌收得率与损失率、存活率相关性试验方法。选择改良ＭＲＳ培养基为离心基质研究了离心力、离心时间、基质ＰＨ对两歧双歧杆菌（Ｂ．ｂｉｆｉｄｕｍ）离心损失率和存活率的影响,确定了活菌收得率最高的适宜离心条件。结果表明：增大离心力和延长离心时间,离心损失率和存活率均显著降低（Ｐ〈０．０１）;影响离心存活率的阈值为４２９７ｇ     

Removal of cadmium and zinc from aqueous solutions using red mud

Red mud, an aluminum industry waste, has been converted into an inexpensive and efficient adsorbent. The product obtained has been characterized and utilized in batch and column operations for the removal of cadmium and zinc from aqueous solutions over a wide range of initial metal ion concentrations (1.78 x 10(-5) to 1.78 x 10(-3) M for Cd2+ and 3.06 x 10(-5) to 3.06 x 10(-3) M for Zn2+; contact time, 24 h) adsorbent dose (5-20 g/L), and pH (1.0-6.0). The removal of Cd2+ and Zn2+ was almost complete at low concentrations, while it was 60-65% at higher concentrations at optimum pH's of 4.0 and 5.0, respectively, with 10 g/L of adsorbent in an 8-10 h equilibration time. The adsorption decreased with increase in temperature. Kinetic studies have been used to describe the mechanism of adsorption. Chemical regeneration of the columns has been achieved with 1% HNO3.     

采用β-环状糊精包埋法去除稀奶油中的胆固醇

研究了不同条件下稀奶油中胆固醇去除率和 β 环状糊精残留率的变化情况。试验结果表明 ,稀奶油经 2 0MPa均质后 ,添加 8 5 % β 环状糊精 ,经 3 0℃混合 1 0min ,4℃静置 1 0min ,40 0 0r/min离心 1 0min处理 ,胆固醇去除率能够达到 84 2 1 % ,β 环状糊精残留率为 1 3 1 3 %。     

Influence of milk centrifugation, brining and ripening conditions in preventing gas formation by Clostridium spp. in Gouda cheese

This study examined milk centrifugation, increased salt concentration, and low ripening temperature as potential strategies to prevent late blowing caused by gas-forming Clostridium spp. in Gouda cheese. The survival of clostridia spores in cheese brine and their ability to enter Gouda cheese during brining was also evaluated. Centrifugation (3000 x g for 30 s) of contaminated milk resulted in > 60% spore reduction, with increased spore reduction at greater centrifugal forces. Low levels of C. tyrobutyricum and C. sporogenes spores survived in saturated (23%, w/v) brine with 2% (v/v) added whey at 15 degrees C for 63 days, while C. beijerinckii and C. butyricum spores were not detectable on days 4 and 35, respectively. Spores of C. tyrobutyricum in brine infiltrated Gouda cheese during 2 h of brining at 13 degrees C resulted in production of small gas holes during ripening. In Gouda cheese slurry stored at 13 degrees C, three C. tyrobutyricum strains plus one of three C. sporogenes strains germinated in the slurry with no added salt. Of three C. tyrobutyricum strains stored at 13 degrees C in slurries with higher water-phase salt concentrations of 2.4 and 3.6%, two strains and one strain germinated, respectively. No germination of spores was detected in any cheese slurry stored at 5 or 8 degrees C. Milk centrifugation, increased percent water-phase salt, absence of spores in brine, and decreased ripening temperature are all potentially important measures against gas production by Clostridium spp. in Gouda cheese.     

β-环糊精脱除猪油中胆固醇的研究

本实验利用三因素二次正交旋转设计,研究了搅拌温度、搅拌时间和β-环糊精添加量对β-环糊精包埋法脱除猪油胆固醇效果的影响,建立了各因素与胆固醇脱除率的回归方程,筛选出了较理想的胆固醇脱除条件,即:搅拌时间90min、搅拌温度45℃和β-环糊精添加量8.5%。在这三个因素中,β-环糊精添加量为主要影响因素,而搅拌时间的影响较小。     

Effect of vinegar on the viability of Giardia duodenalis cysts

The inactivation of Giardia duodenalis cysts by vinegar was investigated. Experiments were carried out in 100 ml volume of vinegar (acetic acid 4%), undiluted or diluted in distilled water in ratios of 1:1, 1:15.6, and 1:62.5 (vol/vol), which were inoculated with 5x10(5) cysts obtained from human feces. Experiments were performed at room temperature (21+/-1 degrees C) and at 4 degrees C. After contact times of 1.5 min, 10, 30, and 60 min, the cysts were recovered from the treatment fluid and subjected to an in vitro excystation assay to determine their viability. The relative viability, which was calculated in relation to controls (maximum excystation percentage), was significantly affected (p<0.1) by the vinegar concentration, contact time, and temperature. At 21+/-1 degrees C, no cysts remained viable after being treated with undiluted vinegar for 60 min, while the treatment with 1:1, 1:15.6, and 1:62.5 vinegar-water mixtures decreased the relative viability to 1.8%, 19.4%, and 56.4%, respectively. The relative viability after corresponding treatments at 4 degrees C also decreased, but 23.6% to 48.8% remained viable after 60 min, and thus complete inactivation was not obtained with any treatment at that temperature.     

Delayed Clostridium perfringens growth from a spore inocula by sodium lactate in sous-vide chicken products

Clostridium perfringens growth from a spore inoculum was investigated in vacuum-packaged, cook-in-bag marinated chicken breast that included 0%, 1.5%, 3%, or 4.8% sodium lactate (NaL; w/w). The packages were processed to an internal temperature of 71.1 degrees C, ice chilled and stored at 4, 19, and 25 degrees C. The total C. perfringens population was determined by plating diluted samples on Tryptose-sulfite-cycloserine agar followed by anaerobic incubation for 48 h at 37 degrees C. At 25 degrees C, addition of 1.5% NaL was effective in delaying growth for 29 h. Increasing the NaL level to 4.8%, C. perfringens growth from a spore inoculum during storage at 25 degrees C for 480 h was not observed. At 19 degrees C, the growth was > 6 log 10 cfu/g by 288 h in control samples. In samples with 3.0% or 4.8% NaL, the growth of C. perfringens from spores was dramatically restricted with little or no growth in 648 h at 19 degrees C. C. perfringens growth was not observed at 4 degrees C regardless of NaL concentration. The D-values at 55 degrees C ranged from 47.40 (no NaL) to 57.58 min (1.5% NaL). Cyclic and static temperature abuse of refrigerated products for 20 h did not permit C. perfringens growth. However, temperature abuse of products for periods 24 h or longer in the absence of NaL led to growth of C. perfringens from a spore inoculum. An extra degree of safety may be assured in such products by supplementation with NaL at 1.5-4.8% NaL level.     

膨润土负载锌-钴催化臭氧处理模拟染料废水

为获得高效的臭氧催化剂,以膨润土作为载体,选择Fe³⁺、Cu²⁺、Mn²⁺、Ni²⁺、Co²⁺、Zn²⁺为活性组分,通过溶液混合法制备负载型催化剂,并以酸性大红模拟印染废水探讨负载型催化剂在催化氧化体系中对酸性大红的降解速率及动力学特点,最终筛选得到最优活性组分;根据正交试验设计获得催化剂最佳制备条件,并通过X射线衍射仪和扫描电子显微镜对其进行表征。试验结果表明:最佳双组分催化剂为膨润土负载Zn-Co催化剂;膨润土负载Zn-Co半峰宽小,晶型好;双组分催化剂最佳制备条件为:煅烧温度400 ℃,煅烧时间3 h,组分浓度1.2 mol/L,锌钴的量比1∶1,淀粉质量1.5 g(对应60 g膨润土)。用在此条件下制得的催化剂处理模拟染料废水时,通入臭氧反应10 min,即可去除 99.92%的酸性大红;且催化剂重复利用4次后,其去除率仍达81.44%。     

黄豆酱杀菌工艺条件的研究

对黄豆酱杀菌工艺进了研究,通过试验初步确定杀菌最佳温度80℃～90℃,杀菌时间5min～10min。通过单因素试验和正交试验确定黄豆酱最佳杀菌工艺条件是：水浴灭菌温度90℃,杀菌时间10min。在最佳条件下杀菌率已经达到86.8%,而且灭菌后感官没有明显变化。