Potato peel-based biopolymer film development using high-pressure homogenization, irradiation, and ultrasound

Edible films were developed from potato peel. High-pressure, gamma-ray, and ultrasound were applied to potato peel solutions to break down biopolymer particles in the solution small enough to allow for biopolymer film formation. Film properties, including moisture barrier and tensile properties, color, and microstructures, were investigated from the films formed with different concentrations of plasticizer (glycerol) and emulsifier (soy lecithin). High-pressure homogenization (HPH) produced the best films among the treatments at the conditions used in this research. Water vapor permeability (WVP) of films decreased by 32% with decrease in the concentrations of glycerol and soy lecithin by 40 and 75%, respectively. As the concentration of glycerol or soy lecithin increased, tensile strength of the films decreased up to 71%, but the elongation at break increased up to 161%, demonstrating lubricant effects of glycerol and soy lecithin. The lightness and yellowness of the films increased and the redness decreased with increase in the concentration of glycerol or soy lecithin. The concentrations of glycerol and soy lecithin were identified as important variables in producing biopolymer films from potato peel.     

Effect of plasticizer-type and genipin on the mechanical, optical, and water vapor barrier properties of canola protein isolate-based edible films

The mechanical properties, opacity, and water vapor permeability of 5.0 % (w/w) canola protein isolate (CPI) films were investigated in the presence and absence of 1 % (w/w of CPI) genipin, and as a function of plasticizer-type [50 % (w/w of CPI); glycerol, sorbitol, and polyethylene glycol 400]. Findings indicated that tensile strength (TS), puncture strength (PS), and elastic modulus (E) values for CPI films prepared with sorbitol were the highest, followed by PEG-400 and then glycerol, whereas tensile elongation (TE) and puncture deformation (PD) values were greater for films prepared with glycerol, followed by PEG-400 and then sorbitol. In all cases, films prepared with genipin were stronger (greater TS, PS, and E) and less flexible (lower TE and PD) than uncross-linked films. Films also showed greater water vapor permeability when prepared with glycerol, followed by PEG-400 and then sorbitol; however, no differences were observed in the presence and absence of genipin. Opacity was least with glycerol present, followed by sorbitol and PEG-400, and increased in the presence of genipin.     

Acute metabolic responses of postpartal dairy cows to subcutaneous glucagon injections, oral glycerol, or both

This study examined the effects of multiple subcutaneous glucagon injections with or without co-administration of oral glycerol on energy status-related blood metabolites and hormones of Holstein dairy cows in the first 2 wk postpartum. Twenty multiparous cows were fed a dry cow ration supplemented with 6 kg of cracked corn during the dry period to increase the likelihood of developing postpartal fatty liver syndrome. Cows with a body condition score of ≥3.5 points (1- to 5-point scale) were assigned randomly to 1 of 4 treatment groups: saline, glucagon, glycerol, or glucagon plus glycerol. Following treatment, serial blood samples were collected over an 8-h period to determine the effects of glucagon and glycerol on blood metabolites and hormones. Treatment effects were determined by comparing the concentrations of metabolites and hormones during the first 4-h period and the entire 8-h period after treatment administration (time 0) with the concentration of the same compounds at time 0 on d 1, 7, and 13 postpartum. Administration of glucagon alone increased concentrations of plasma glucagon and insulin on d 1, 7, and 13 and increased plasma glucose and decreased plasma nonesterified fatty acids (NEFA) on d 7 and 13 postpartum relative to the saline group. Administration of glycerol alone increased plasma glucose on d 7 and plasma triacylglycerols on d 1 postpartum. Glycerol administration also decreased plasma glucagon and NEFA on d 1, 7, and 13 and plasma β-hydroxybutyrate (BHBA) on d 1 postpartum relative to the saline group. Administration of glucagon plus glycerol increased and sustained concentrations of plasma glucagon, glucose, and insulin on d 1, 7, and 13 and decreased plasma NEFA on d 1, 7, and 13 and BHBA on d 1 and 7. Early postpartal treatment of dairy cows with glucagon plus glycerol increased plasma glucose and insulin, decreased plasma NEFA and BHBA, and increased secretion of liver NEFA as plasma triacylglycerols. This suggests that glucagon and glycerol, when co-administered, act to decrease the likelihood of metabolism-related syndrome development in dairy cows.     

Chronic metabolic responses of postpartal dairy cows to subcutaneous glucagon injections, oral glycerol, or both

We examined the long-term effects of daily subcutaneous injections of 15 mg of glucagon during the first 14 d postpartum with or without coadministration of 400 mL of pure glycerol orally on blood metabolites and hormones and liver composition of Holstein dairy cows during early lactation. Fourteen multiparous cows with body condition score of ≥3.5 points (1-5 point scale) were assigned randomly to one of 4 treatment groups—saline, glucagon, glycerol, or glucagon plus glycerol. Fatty liver syndrome was induced by feeding cows a dry-cow ration supplemented with 6 kg of cracked corn daily during the last 6 wk of the dry period. Compared with saline treatment (n = 3), coadministration of glucagon and glycerol (n = 4) increased plasma glucose and insulin and decreased plasma nonesterified fatty acid concentrations in both treatment weeks, whereas glucagon alone (n = 3) produced similar changes plus a decrease in plasma β-hydroxybutyrate in the second week only. No significant changes were observed for the glycerol alone treatment (n = 4). We conclude that a single daily dose of glycerol for the first 14 d postpartum may potentiate the action of glucagon in the first treatment days to alleviate some symptoms of fatty liver syndrome, such as the increase in plasma nonesterified fatty acids and the decrease in plasma glucose and insulin, in Holstein dairy cows after parturition.     

Effects of supplementing glycerol and soybean oil in drinking water on feed and water intake, energy balance, and production performance of periparturient dairy cows

The objective of this study was to determine the effects of supplementing glycerol and soybean oil in drinking water on feed and water intake, calculated energy balance, and production performance of periparturient dairy cows. Ninety multiparous Holstein dairy cows were randomly assigned to 1 of 3 treatments: 1) no nutrients supplemented in the drinking water (control); 2) 20 g/L of glycerin supplemented in the drinking water (glycerol); and 3) 10 g/L of soybean oil supplemented in the drinking water (SBO). The trial lasted from 7 d prepartum to 7 d postpartum. Cows were offered a close-up and milking cow TMR for ad libitum intake, pre- and postpartum, respectively. The dry matter intake of cows supplemented with glycerol and SBO was lower than for the control cows throughout the experimental period but not different from each other. Water intake for the control cows was greater than the average for the glycerol and SBO cows prepartum, and greater than for SBO cows but similar to that of glycerol cows postpartum. Glycerol cows consumed more water than SBO cows. There were no differences in energy intake and energy balance of the cows pre- and postpartum. Serum triacylglycerol concentration for glycerol cows was lower than for the control and SBO cows prepartum and was lower than for the SBO cows postpartum. There were no differences in the serum nonesterified fatty acids and glucose concentrations throughout the experiment. There were no differences in the serum β-hydroxybutyrate (BHBA) concentrations at parturition, but serum BHBA concentration of the glycerol cows was greater than for control and SBO cows during the prepartum period. However, during the postpartum period, serum BHBA concentrations of the control cows were greater than for glycerol and SBO cows. There were no differences in calf birth weights or milk yield and composition. Although the glucogenic property of glycerol supplemented in the drinking water at 20 g/L may not have been sufficient to elicit a milk yield response, it did reduce the concentration of BHBA postpartum.     

Effects of replacing wheat starch with glycerol on methane emissions,milk production,and feed efficiency in dairy cows fed grass silage-based diets

To lower the effect of climate change from cattle production, we should aim at decreasing their enteric methane emissions per kilogram of milk or meat. Glycerol may be absorbed through the rumen epithelium and would consequently be less available to microbes in the rumen. Glycerol could thus supply dairy cows with energy for milk production without contributing much to methane production. This study evaluated the effect of replacing wheat starch with glycerol on milk production, feed intake, and methane emissions. Twenty-two Swedish Red cows in mid lactation were used in a switch-back, change-over experiment with 3 periods of 21 d. The 2 dietary treatments consisted of a total mixed ration based on (g/kg of dry matter) grass silage (605), rapeseed meal (120), and barley (70) and either wheat starch or refined glycerol (200) fed ad libitum. The glycerol diet resulted in higher dry matter intake (21.6 vs. 20.1 kg/d) and methane emissions (482 vs. 423 g/d) compared with the diet containing wheat starch, whereas no difference was found in energy-corrected milk yield (28.4 vs. 29.7 kg/d). These results indicate that when glycerol is mixed with the feed, it is available to rumen microbes to a larger extent than initially assumed. Compared with wheat starch, adding refined glycerol (200 g/kg of dry matter) to the feed of dairy cows does not seem to have the potential to decrease enteric methane emissions.     

Barrier and Tensile Properties of Transglutaminase Cross-linked Gelatin Films as Affected by Relative Humidity, Temperature, and Glycerol Content

Gelatin films were prepared by enzymatic cross-linking with transglutaminase, and their mechanical and barrier properties were evaluated as functions of relative humidity (RH, 30 to 75%), temperature (15 to 35°C) and glycerol content (15 to 31%). Water and glycerol plasticized the films synergistically, resulting in greater elongation but lower tensile strength values. Films with higher glycerol contents exhibited higher moisture contents, indicating higher hydrophilicity of the films. Permeabilities of oxygen and allyl isothiocyanate (an antimicrobial vapor from Cruciferae plants) were low when the films were dry, but increased considerably when RH>50%. Therefore, RH conditions during end-use applications must be considered to optimize the performance of these films.     

Effects of Mica, Carnauba Wax, Glycerol, and Sodium Caseinate Concentrations on Water Vapor Barrier and Mechanical Properties of Coated Paper

ABSTRACT: The combined effects of mica (0% to 1.2% [w/w]), carnauba wax (0% to 0.8% [w/w]), glycerol (0% to 6% [w/w]), and sodium caseinate (10% to 13% [w/w]) concentrations on water vapor barrier and mechanical properties of coated paper were studied. A Doehlert matrice was used to investigate the main effects of these factors and their different interactions. The results were analyzed using the response surface methodology. Carnauba wax and glycerol concentrations were the most important parameters affecting water vapor permeability (WVP). Glycerol enhanced WVP as its concentration increased. Carnauba wax and mica factors decreased WVP of coated paper. Conversely, increasing the amount of glycerol led to a decrease in tensile strength (TS) and to an increase in elongation (%E) of the resulting coated papers.     

用克雷伯氏菌批式流加发酵法生产1,3-丙二醇

通过对克雷伯氏菌在 7L发酵罐中厌氧间歇发酵甘油生产 1,3 丙二醇的实验研究 ,建立了一种与 pH调节相偶联的批式流加甘油发酵策略。考察了不同甘油维持浓度条件下的流加方式及不同培养方式对 1,3 丙二醇产率的影响。结果表明 ,甘油质量分数维持在 2 %的流加方式有利于 1,3 丙二醇的发酵生产 ,其在 30 5h内消耗甘油 2 80 g ,得到 1,3 丙二醇152 6 g ,摩尔转化率 6 5 5% ,生产强度 0 91g/L·h     

Physical,mechanical, and antimicrobial properties of ethylene vinyl alcohol copolymer/chitosan/nano-ZnO (ECNZn) nanocomposite films incorporating glycerol plasticizer

In this study the ethylene vinyl alcohol copolymer (EVOH) and chitosan polymers mixture film containing nano zinc oxide (nano-ZnO) and glycerol was developed for food packaging. Physical, mechanical and antimicrobial properties of the film matrix were evaluated at different ratios of the biodegradable polymers (0:100, 25:75, 50:50, 75:25, 100:0) which contain nano-ZnO and incorporate with glycerol as the plasticizer. Film topography and cross-sections were evaluated by FE-SEM and AFM examinations. To assess characterization of the nanocomposites structure and network chemistry, FTIR spectroscopy was considered. The results indicate that EVOH improved barrier properties, transparency and mechanical properties. The antimicrobial properties were improved by adding chitosan. With adding glycerol decreases in barrier properties and increases in percentage of elongation at break (ε_b) were observed. Adding nano-ZnO improved barrier, mechanical and antimicrobial properties and significantly reduced the adverse effects of glycerol. Taken together, these data reveal that the new nanocomposite provides the better properties and the less adverse effects of plasticizer on matrix film.     

Correlations between structural,barrier, thermal and mechanical properties of plasticized gelatin films

The aims of this work were to develop gelatin films using glycerol as plasticizer (0–100% based on protein mass) and to establish relationships between glycerol content and structural, barrier, thermal and mechanical film properties. These correlations were established since WVP exhibited a minimum for films containing 20 g glycerol/100 g gelatin, while flexibility increased from 2.2% to 180.9% and T_g shifted from 137.5 to 21.3 °C, for films without glycerol and plasticized films with 80 g glycerol/100 g gelatin, respectively. Furthermore, a satisfactory fit between T_g experimental data and predicted values by Couchman and Karasz's equation was found, with glycerol ranging from 0 to 60 g/100 g gelatin. T_g values correlated inversely with film moisture content, and both mechanical and thermal properties showed a strong dependence since elastic modulus and T_g followed a similar trend. Films exhibited similar X-ray patterns regardless of the glycerol concentration, showing a displacement in the position of the peak located at around 2θ = 8°, which shifted towards lower 2θ values with glycerol content.The abovementioned correlations between film physical properties and glycerol content, would allow to select the optimum conditions to develop, process and manage gelatin films according to specific requirements.Industrial relevanceThe methodology used in this work is of considerable importance for the film development and could be used in industrial applications. The management of film formulations and the function that each component plays could allow to obtain tailormade films. A series of relationships between film properties based on gelatin was found, as well as between these properties and glycerol content of the films. An inflexion point in the behavior and microstructure of these materials was established due to glycerol concentration. The addition of higher quantities of glycerol than that corresponds to the abovementioned point, would not be recommendable since the properties are not modified and moreover, it is not profitable. These results would allow better management of film formulations and an appropriate selection of plasticizer concentration in accordance with the specific requirements of potential users.     

HEAT INACTIVATION OF ESCHERICHIA COLI 0157:H7 IN APPLE CIDER IN THE PRESENCE OF GLYCEROL MONOLAURATE AND A SYNTHETIC ANTIMICROBIAL PEPTIDE, PR-26

The effect of moderate temperatures in combination with glycerol monolaurate and an antimicrobial peptide, PR-26 on E. coli 0157:H7 in apple cider was determined. A five-strain mixture of E. coli 0157:H7 was inoculated into apple cider (pH 3.53) containing 0.01% PR-26 or 0.02% glycerol monolaurate or a combination of 0.01% PR-26 and 0.02% glycerol monolaurate. The apple cider was incubated at 40, 45 or 50C for 30 s, 5 min, 10 min, and 15 min. At each of the specified time intervals, the surviving population of E. coli 0157:H7 was determined. At all the three temperatures, there was no significant difference (P > 0.05) between the E. coli 0157:H7 populations of the control and the treatment containing PR-26. However, the treatments containing glycerol monolaurate alone or combination of glycerol monolaurate and PR-26 resulted in significant reductions (P < 0.05) in E. coli 0157:H7 counts. Results indicate that addition of glycerol monolaurate (0.02%) to apple cider and heating at 50C for 5 min can reduce E. coli 0157:H7 by 5.0 log CFU/mL.     

甘油半乳糖苷的分离纯化及鉴定

以半乳糖和甘油为原料,β-半乳糖苷酶为催化剂,制备甘油半乳糖苷。采用活性炭吸附法对其分离纯化,采用L9（34）正交试验对分离纯化的工艺条件进行优化筛选,进一步用G-15色谱柱纯化,以获得高纯度的甘油半乳糖苷。结果表明：活性炭吸附法分离纯化甘油半乳糖苷的最佳工艺条件为反应液稀释倍数20、活性炭用量2 g/mL、洗脱剂乙醇体积分数30%,甘油半乳糖苷的回收率和纯度分别为62.53%和48.84%,分别比单因素试验结果高4.52%和4.76%;经G-15柱色谱进一步纯化,甘油半乳糖苷的纯度达到97.80%;经质谱鉴定合成产物为甘油单半乳糖苷。     

普鲁兰、甘油共混对结冷胶食用膜性能的影响

研究了普鲁兰、甘油共混对结冷胶食用性膜的机械性能、水蒸汽透过率、阻氧性和吸水率的影响。结果表明,普鲁兰的添加,提高了结冷胶食用膜的延展性、水蒸汽透过率和阻氧性,但降低了结冷胶食用膜的抗拉强度和吸水率;甘油增加了膜的延展性和水蒸汽透过率,但降低了膜的阻氧性。     

Impact of cosolvents (polyols) on globular protein functionality: Ultrasonic velocity, density, surface tension and solubility study

The objective of this study was to understand how cosolvents influence the molecular and functional properties of globular proteins in aqueous solutions. The ultrasonic velocity, density and adiabatic compressibility of cosolvent solutions (0–50 wt% sorbitol or glycerol) were measured in the absence and presence of a globular protein (1 wt% β-lactoglobulin) at 30 °C. These measurements were used to calculate the partial specific apparent volume and adiabatic compressibility of the protein. The protein's volume decreased and its compressibility increased in the presence of high cosolvent concentrations, which were attributed to changes in the properties of the protein interior and solvation layer. Sorbitol was more effective than glycerol at decreasing the protein volume at high cosolvent concentrations, which may be because glycerol has some surface activity and may therefore accumulate around hydrophobic regions on the protein surface. Our data were used to account for the observation that sorbitol is more effective than glycerol at increasing the thermal stability and self-association of the β-lactoglobulin. A better understanding of the influence of protein–cosolvent–solvent interactions on the functionality of globular proteins may facilitate the design of protein-based products.     

Replacing corn with glycerol in diets for transition dairy cows

Expansion of the biofuels industry has increased the availability of glycerol as an alternative feed for dairy cows. The objective of this study was to determine the effects of glycerol on feed intake, milk production, rumen volatile fatty acids, and metabolic parameters in transition dairy cows. Multiparous Holstein cows were fed diets containing either high-moisture corn (n = 11) or glycerol (n = 12) from −28 to +56 d relative to calving. Glycerol was included at 11.5 and 10.8% of the ration dry matter for the pre- and postpartum diets, respectively. Prepartum feed intake was not changed by glycerol feeding (14.9 vs. 14.6 kg/d, control vs. glycerol) nor did postpartum feed intake differ (19.8 vs. 20.7 kg/d, control vs. glycerol). Overall milk yield did not differ (35.8 vs. 37 kg/d, control vs. glycerol) and milk composition, milk urea nitrogen, somatic cells, and energy balance were not different with glycerol feeding. Blood glucose content was decreased in cows fed glycerol during the prepartum period (59.1 vs. 53.4 mg/dL), and β-hydroxybutyrate concentration was increased (0.58 vs. 0.82 mmol/L, control vs. glycerol). Concentrations of blood nonesterified fatty acids did not differ between the treatment groups, and no response to glycerol for blood metabolites during the postpartum period was observed. Total rumen volatile fatty acid concentrations (mmol/L) did not differ between treatments, but proportions of rumen propionate and butyrate were greater for cows fed glycerol (22.7 vs. 28.6% of propionate, control vs. glycerol; and 11.5 vs. 15.3% of butyrate, control vs. glycerol) at the expense of acetate (61.4 vs. 51.5%, control vs. glycerol). These data indicate that glycerol is a suitable replacement for corn grain in diets for transition dairy cows.     

卷烟中非挥发性有机酸、糖类、某些氨基酸和磷酸的同时测定

以山梨醇作内标,羟胺吡啶和BSTFA 1%TMCS为衍生化剂,采用GC法同时测定了国内外21种牌号卷烟中的木糖、阿拉伯糖、鼠李糖、果糖、甘露糖、半乳糖、葡萄糖、蔗糖、麦芽糖、天门冬氨酸、天门冬酰胺、丙二醇、丙三醇、乳酸、丙二酸、苹果酸、柠檬酸和磷酸。结果显示:①丙二醇和阿拉伯糖的RSD>10%,乳酸、天门冬酰胺、鼠李糖、半乳糖和麦芽糖的RSD>5%,其它成分的RSD<5%;②除丙二酸、半乳糖、鼠李糖、丙三醇和阿拉伯糖的回收率介于70%~75%外,其它组分的回收率>80%;③在所分析的卷烟样品中,进口混合型卷烟中柠檬酸、天门冬氨酸、天门冬酰胺、丙二醇和丙三醇含量较国产烤烟型卷烟的高,而糖类的含量则普遍较低,其它成分差别不大。     

Reduction of nitroglycerin with elemental iron: pathway, kinetics, and mechanisms

Nitroglycerin (NG) is a nitrate ester used in dynamites, propellants, and medicines and is therefore a common constituent in propellant-manufacturing and pharmaceutical wastewaters. In this study we investigated the reduction of NG with cast iron as a potential treatment method. NG was reduced stepwise to glycerol via 1,2- and 1,3-dinitroglycerins (DNGs) and 1- and 2-mononitroglycerins (MNGs). Nitrite was released in each reduction step and was further reduced to NH4+. Adsorption of NG and its reduction products to cast iron was minimal. A reaction pathway and a kinetic model for NG reduction with cast iron were proposed. The estimated surface area-normalized reaction rate constants for NG and NO2- were (1.65 +/- 0.30) x 10(-2) (L x m(-2) x h(-1)) and (0.78 +/- 0.09) x 10(-2) (L x m(-2) x h(-1)), respectively. Experiments using dialysis cell with iron and a graphite sheet showed that reduction of NG to glycerol can be mediated by graphite. However, reduction of NO2- mediated by graphite was very slow. NG and NO2- were also found to reduce to glycerol and NH4+ by Fe2+ in the presence of magnetite but not by aqueous Fe2+ or magnetite alone. These results indicate that in a cast iron-water system NG may be reduced via multiple mechanisms involving different reaction sites, whereas nitrite is reduced mainly by iron and/ or adsorbed Fe2+. The study demonstrates that iron can rapidly reduce NG to innocuous and biodegradable end products and represents a new approach to treat NG-containing wastewaters.     

Physical Properties of WPI Films Plasticized with Glycerol, Xylitol, or Sorbitol

ABSTRACT: Effects of glycerol, xylitol, and sorbitol on selected physical properties of whey protein isolate (WPI) films were examined. Increasing glycerol or sorbitol content led to increases in moisture content, water vapor permeability, and % elongation; and decreases in tensile strength, elastic modulus, and glass transition temperatures of the films. Increasing levels of xylitol had no effect on permeability, moisture content, or glass transition temperature of the films, but decreased % elongation, tensile strength, and elastic modulus. Moisture content of the films correlated well with glass transition temperatures. Differences in measured physical properties of films with plasticizer type and concentration may be attributed to differences in the hygroscopic and crystalline properties of the plasticizers.     

Monitoring of monosaccharides,oligosaccharides, ethanol and glycerol during wort fermentation by biosensors,HPLC and spectrophotometry

The aim of the present study was to analyze sugar levels (namely maltose, maltotriose, glucose and fructose) and alcohols (ethanol and glycerol) during the fermentation process in wort samples by amperometric enzymatic biosensors developed by our research group for industrial application, HPLC and spectrophotometry, and to compare the suitability of the presented methods for determination of individual analytes. We can conclude that for the specific monitoring of maltose or maltotriose only the HPLC method was suitable. On the other hand, biosensors and spectrophotometry reflected a decrease in total sugar concentration better and were able to detect both glucose and fructose in the later stages of fermentation, while HPLC was not. This can be attributed to the low detection limits and good sensitivity of the proposed methods. For the ethanol and glycerol analysis all methods proved to be suitable. However, concerning the cost expenses and time analysis, biosensors represented the best option.