Increasing Storage Temperature Research Articles

Carotenoid stability in high total solid spray dried emulsions with gum Arabic layered interface and trehalose–WPI composites as wall materials

Abstract The present study investigated the ability of spray dried single layer (SL) and layer-by-layer (LBL) high total solid emulsions with carbohydrate (trehalose) and non-carbohydrate (WPI) solids to stabilize carotenoids upon storage at 35 °C, 50 °C, and 65 °C. Carotenoid loss followed first order loss kinetics, and increased with increasing storage temperature. Rapid initial first order loss followed by a second, less rapid first order loss was observed. Storage of the systems above the T g reduced carotenoid loss in the initial first order loss. The loss of carotenoids in LBL system was more temperature dependent initially but SL system was more temperature dependent in the second first order loss step. LBL system showed slower loss rate of carotenoids in the initial first order loss step and at 65 °C in the second step. Carotenoid retention was significantly higher in LBL system upon storage at 65 °C. Industrial relevance Although layer-by-layer (LBL) technique has been known to produce emulsions with better stability towards environmental stresses, few have reported the application of LBL technique using systems with high total solids. The application of LBL technique on emulsion with high total solids and subsequent spray-drying of the emulsion in this manuscript will provide useful information to the food and pharmaceutical industries. The possibility to spray-dry such systems with high total solids producing high quality powders would be feasible to the industry as it greatly reduces production cost. The present study also reports on the carotenoid loss kinetics of dehydrated concentrated systems with carbohydrate and non-carbohydrate mixtures as wall materials and compares the ability of single layer (SL) and LBL systems in preventing the loss of the encapsulated carotenoids.

Anaerobic Digestion and Storage Influence Availability of Plant Hormones in Livestock Slurry

Anaerobic digestion slurry (ADS) is typically applied as a liquid fertilizer and soil amendment because it contains high concentrations of plant nutrients. For many years, macronutrients such as nitrogen and phosphorus in ADS has been widely studied, whereas little attention has been paid to plant hormones. Lab-scale batch experiments were conducted to evaluate the effect of anaerobic digestion (AD) on plant hormones (gibberellic acid (GA3), indoleacetic acid (IAA), abscisic acid (ABA)) in three typical animal manures (chicken, dairy, and pig). Results from the lab-scale batch experiments revealed that ADS contained higher concentrations of plant hormones than the original animal manures. Subsequently, quantitative analysis of samples from large-scale continuously fed biogas plants verified the high contents of plant hormones in ADS. However, the storage experiment demonstrated a significant loss of plant hormones in ADS prior to land application because of decomposition and transformation. Specifically, the results showed that the patterns of GA3, IAA, and ABA variations depended on the storage temperature, showing increased losses at increased storage temperatures. Consequently, it is important to assess plant hormones availability in ADS prior to indiscriminate application for efficient utilization.

WATERMELON FRUITS PROPERTIES AS AFFECTED BY STORAGE CONDITIONS

The main objective of this article was to study the physical and mechanical properties of watermelon fruits as influenced by storage temperatures. Watermelon fruits with different sizes were stored at two temperatures (15 and 30°C). The results indicated that, the length, major diameter and minor diameter of watermelon fruit value ranged from 22.18 to 28.77 cm, 21.34 to 27.07 cm and 18.92 to 23.01cm, respectively. The spherical coefficient and the geometric mean diameter of the watermelon fruits decreased from 0.933 to 0.907 and 20.70 to 26.08 cm, respectively. The surface area and volume of watermelon fruit values ranged from 1487.10 to 2447.61cm2 and 5393.90 to 11389.44 cm3, respectively. The density of the watermelon fruits ranged from 927.84 to 973.57 kg m-3. The thickness of rind of the watermelon fruits ranged from 12.11 to 20.28 mm. The mass of flesh, seeds and rind of watermelon fruit values ranged from 2.929 to 6.277 kg, 0.096 to 0.208 kg and 1.992 to 4.603 kg, respectively. The repose angle and the crushing load of the watermelon fruits increased from 49.67 to 71.00o and 2.333 to 4.600 kN. The change of watermelon fruits dimensions and weight decreased with increasing storage temperature and time. The crushing load of the watermelon fruits decreases with decreasing storage temperature and decreasing watermelon fruit sizes. The marketable watermelon fruits percentage ranged from 75.67 to 90.00% at 15 oC and from 25.00 to 48.00% at 30oC.

The Storage Stability of Anthocyanins in Mao (Antidesma thwaitesianumMüll. Arg.) Juice and Concentrate

Mao or Makmao ( Antidesma thwaitesianum Mull. Arg.) is a wild plant found in the northeast of Thailand. Mao is one of fruits which are source of anthocyanins. Mao fruits are used for juice and concentrate which are consumed for healthy drinks. Determination of the kinetic parameters is essential to predict the quality changes and stability of anthocyanins in Mao juice and concentrate that occur during storage. The purpose of this research was to study the degradation of anthocyanins in Mao juice and concentrate during storage at 5, 30 and 37°C for 15 days. The storage stability of Mao anthocyanins was studied in 15°Brix juice and 45°Brix concentrate. The degradation kinetic (k), half-life (t 1/2 ), activation energy (E a ) and Q 10 values for Mao anthocyanins degradation were determined. The results indicated that analysis of kinetic data for the degradation of anthocyanins followed a first-order reaction. An increase storage temperature from 5 to 30 and 37°C increased k value of anthocyanins in Mao juice and concentrate. Increasing storage temperature decreased t 1/2 value of anthocyanins in both concentrations. At 5, 30 and 37°C, the t 1/2 of anthocyanins decreased from 35 to 13 and 5 days for Mao juice and 32 to 25 and 21 days for Mao concentrate. The E a value of the anthocyanins degradation in Mao juice and concentrate were 38.03 and 8.42 kJ/mol, respectively. Q 10 values of both Mao juice and concentrate at 30-37°C were higher than those were storaged at 5-30°C. Thus higher stability of anthocyanins was achieved by using concentration and storage at lower temperature.

Efeito da temperatura de armazenamento na conservação pós-colheita de amora-preta

RESUMO Os frutos da amoreira-preta apresentam vida útil relativamente curta, devido à sua estrutura frágil, alto metabolismo e ocorrência de doenças, exigindo, portanto, cuidados em seu armazenamento. Objetivou-se avaliar o efeito de diferentes temperaturas na conservação de amora-preta (cv. Brazos), caracterizando os atributos físico-químicos e quantificando os patógenos causadores de podridões. Utilizou se delineamento experimental inteiramente casualizado, em esquema fatorial (temperaturas x pomares), com três repetições de 10 frutos por tratamento. As temperaturas de 2 ºC e 5 ºC foram eficientes em retardar a mudança de coloração e a degradação dos ácidos orgânicos. Observou-se aumento significativo na incidência de podridões com o aumento da temperatura de armazenamento. Incidências inferiores a 7 % foram observadas ao final do armazenamento a 2 ºC e 5 ºC, mas superaram 20 % em temperaturas a partir de 15 ºC. Os principais pátogenos detectados foram Cladosporium spp. e Colletotrichum spp. A refrigeração a 2 ºC e 5 ºC constitui eficiente alternativa para manter a qualidade dos frutos de amora-preta por até nove dias, por retardar o amadurecimento e o desenvolvimento de podridões.

Storage of fresh-cut swede and turnip: Effect of temperature, including sub-zero temperature, and packaging material on sensory attributes, sugars and glucosinolates

Freezing point of fresh-cut swede (Brassica napus L. var. napobrassica Rchb.) and turnip (Brassica rapa L. ssp. rapifera Metzg.) dice was measured by the cooling curve method, and mean equilibrium freezing points were found to be −2.67 and −1.97°C, respectively. This indicates that storage of fresh-cut swede and turnip at temperatures below 0°C is possible. Fresh-cut swede and turnip were packed in pouches made of biaxially oriented polypropylene film, and a film based on polylactic acid, and stored for 10 d at −2, 0, 5 and 10°C. One sample of each vegetable was stored at −2°C for 5 d, followed by 5 d of storage at 5°C. Differences in sensory quality between storage at −2°C and 0°C were found in appearance attributes only. Both swede and turnip had higher evenness of colour at −2°C than at 0°C. Storage at −2°C vs. 0°C gave lower whiteness for swede but higher for turnip, and lower intensity of hue for turnip only. Increased storage temperature from 0°C to 5 or 10°C did not change appearance in swede, but in turnip hue and colour intensity increased, and colour evenness and whiteness decreased. Differences in odour, taste and flavour during storage at 5 or 10°C vs. 0°C were prominent for turnip: decreased sour odour and flavour, green odour and flavour, sulphurous odour and sweet taste, and increased muddy odour and cloying odour and flavour for 5°C or 10°C. For swede, higher storage temperature gave only increased intensity of sulphurous odour and pungent odour. Texture changed for turnip only with decreased juiciness with increased temperature. The lowest temperature (−2°C) gave the highest sucrose content in both swede and turnip, the highest total sugar content in turnip and the lowest glucose content in swede. Higher storage temperature resulted in higher content of total indolic glucosinolates in both fresh-cut swede and turnip, but a lower content of total aliphatic glucosinolates in turnip only. Increased contents with increased storage temperature were found for glucobrassicin and 4-methoxyglucobrassicin in both vegetables, and decreased contents for glucobrassicanapin and gluconapin in turnip and glucoalyssin in swede. Storage in polylactic acid film resulted in higher weight loss than the biaxially oriented polypropylene film in both vegetables.

Effect of high pressure processing in combination with Weissella viridescens as a protective culture against Listeria monocytogenes in ready-to-eat salads of different pH

This study explored the effect of HPP (400 MPa/1 min) and a Weissella viridescens protective culture, alone or in conjunction, against Listeria monocytogenes in ready-to-eat (RTE) salads with different pH values (4.32 and 5.59) during storage at 4 and 12 °C. HPP was able to reduce the counts of the pathogen after treatment achieving approximately a 4.0 and 1.5 log CFU/g reduction in the low and higher pH RTE salad, respectively. However, L. monocytogenes was able to recover and grow during subsequent storage. W. viridescens grew in both RTE salads at both storage temperatures, with HPP resulting in only a small immediate reduction of W. viridescens ranging from 0.50 to 1.2 log CFU/g depending on the pH of the RTE salad. For the lower pH RTE salad, the protective culture was able to gradually reduce the L. monocytogenes counts during storage whereas for the higher pH RTE salad in some cases it delayed growth significantly or exerted a bacteriostatic effect. exerted a bacteriostatic effect. The results revealed that the increased storage temperature led to an increase in the inactivation/inhibition of L. monocytogenes in the presence of W. viridescens. The combination of HPP and W. viridescens is a promising strategy to control L. monocytogenes and can increase safety even when a break in the chill chain occurs.

Physico-Chemical Changes in Popular Kenyan Processing Potato Varieties as Influenced by Storage Condition

The current study sought to establish the physico-chemical changes in popular Kenyan potato varieties, Shangi, Dutch Robijn, Kenya Mpya, Asante and Tigoni, under different storage conditions. Tubers were harvested at maturity and stored at varied relative humidity (82-92 %) and temperature (20-24 oC, 12-14 oC, 8-10 oC and 4-6 oC).The tubers were monitored for reducing sugars content, dry matter content, ascorbic acid content, greening, weight loss and sprouting. Results indicated that reducing sugars significantly (p<0.05) increased with time with the increase being pronounced at lower temperatures. At harvest, for instance, reducing sugars were 0.17 % in Shangi, this increased after 10 weeks of storage to 0.21 %, 0.31 %, 0.68 % and 0.89 % at ambient, 12-14 oC, 8-10 oC, 4-6 oC, respectively. The scenario was similar for Dutch Robijn, Asante, Kenya Mpya and Tigoni where increases were noted after a month of storage. Reduced ascorbic acid (vitamin C) in tubers decreased significantly (p<0.05) with storage time irrespective of storage temperature. Dry matter content varied significantly (p<0.05) with storage temperature and time. Prevalent ambient storage seemed to have higher increase in dry matter compared to lower temperature storage. The increase in dry matter content was more pronounced (p<0.05) in Asante and Kenya Mpya than in Dutch Robijn and Tigoni varieties. Weight loss was minimal in all the storage conditions being less than 5% while sprouting increased significantly (p<0.05) with storage time and with increased storage temperature. At ambient temperature and 12-14 oC, sprouts emerged in Shangi after 2 weeks and increased steadily with time reaching 43 mm after 10 weeks. Sprouts emerged after 2 months of storage in Dutch Robijn, Kenya Mpya and Asante being pronounced at 12-14 oC and ambient storage. Lower storage temperatures inhibited sprout growth and weight loss but significantly increased reducing sugars beyond processing requirements.

A storage study of encapsulated gac (Momordica cochinchinensis) oil powder and its fortification into foods

This study investigated the effects of different storage conditions, temperatures of −20, 10, room temperature (RT), 40 and 63°C for up to 12 months in the presence or absence of air and light, on the stability of an encapsulated gac (Momordica cochinchinensis) oil powder. A stability trial of the encapsulated oil powder incorporated into yoghurt, pasteurised milk and cake mix stored at 4±0.5°C and RT for different storage times was also carried out. The results showed that a progressive degradation of colour, β-carotene and lycopene, and a progressive increase in surface oil content and peroxide value (PV) occurred in the encapsulated powders with increasing storage temperatures and storage times. However, the degradation was much less when the encapsulated powder was stored at low temperature in the absence of air and light. The degradation of β-carotene and lycopene in all samples during storage fitted a first-order reaction. The sorption curves of the encapsulated powders at 10, 30 and 40°C were fitted with BET and GAB models. The results also showed that the encapsulated gac oil powder could be successfully incorporated into food products in terms of retention of colour, β-carotene and lycopene, and low PV.

Study of chemical changes in pasteurised orange juice during shelf-life: A fingerprinting-kinetics evaluation of the volatile fraction

The current work used fingerprinting-kinetics for the first time to monitor shelf-life changes in a low-pH, pasteurised, shelf-stable product, more particular in orange juice. Orange juice samples were stored as a function of time at four different storage temperatures (20, 28, 35 and 42°C). To obtain insight into chemical changes in the volatile food fraction, samples were fingerprinted with headspace GC–MS. The objectives of this work were twofold: (i) to identify major chemical changes of pasteurised orange juice during shelf-life and (ii) to study the kinetics of selected shelf-life compounds in the context of accelerated shelf-life testing (ASLT). At 20°C, changes in terpenes and a decrease in aldehydes were observed. Oxides and sulphur compounds increased and esters decreased at increased storage temperatures (at 28°C and above). Concerning ASLT, four volatile compounds had clear temperature and time dependent kinetics within the investigated temperature range.

Effect of Storage Temperature on Structure and Function of Cultured Human Oral Keratinocytes.

Purpose/AimsTo assess the effect of storage temperature on the viability, phenotype, metabolism, and morphology of cultured human oral keratinocytes (HOK).Materials and MethodsCultured HOK cells were stored in HEPES- and sodium bicarbonate-buffered Minimum Essential Medium (MEM) at nine temperatures in approximately 4°C increments from 4°C to 37°C for seven days. Cells were characterized for viability by calcein fluorescence, phenotype retention by immunocytochemistry, metabolic parameters (pH, glucose, lactate, and O2) within the storage medium by blood gas analysis, and morphology by scanning electron microscopy and light microscopy.ResultsRelative to the cultured, but non-stored control cells, a high percentage of viable cells were retained only in the 12°C and 16°C storage groups (85%±13% and 68%±10%, respectively). Expression of ABCG2, Bmi1, C/EBPδ, PCNA, cytokeratin 18, and caspase-3 were preserved after storage in the 5 groups between 4°C and 20°C, compared to the non-stored control. Glucose, pH and pO2 in the storage medium declined, whereas lactate increased with increasing storage temperature. Morphology was best preserved following storage of the three groups between 12°C, 16°C, and 20°C.ConclusionWe conclude that storage temperatures of 12°C and 16°C were optimal for maintenance of cell viability, phenotype, and morphology of cultured HOK. The storage method described in the present study may be applicable for other cell types and tissues; thus its significance may extend beyond HOK and the field of ophthalmology.

Microencapsulation of phenolic compounds from olive pomace using spray drying: A study of operative parameters

In this work, polyphenols from olive pomace were extracted with a high pressure-high temperature agitated reactor and for the first time encapsulated by spray drying, using maltodextrin as coating agent at different concentrations. In addition, effects of inlet temperature (130 °C and 160 °C) and feed flow (5 mL/min and 10 mL/min) were studied. Physicochemical, antioxidant properties and stability of microparticles were evaluated. High inlet temperature implied lower moisture and bulk density without affecting antioxidant properties. Increasing maltodextrin concentration caused lower bulk density and higher microparticles sizes, while higher feed flow lead to increased moisture content. Spray drying at inlet temperature of 130 °C, maltodextrin concentration of 100 g/L and feed flow of 10 mL/min, resulted in high microencapsulation yield (94%) and encapsulation efficiency (76%) with high polyphenols content (39.5 mgCAE/gDP) and antiradical power (33.8 mmolDPPH/Lextract). HPLC and thermogravimetric analysis revealed the thermal protection effect of maltodextrin for phenolic compounds. Microcapsules were stable at 5 °C in dark condition for 70 days, and only 21% were degraded increasing storage temperature up to 25 °C. UV light exposure resulted in a 66% loss in polyphenols after 48 h of exposure.

Comparison of Desiccation Tolerance among Listeria monocytogenes, Escherichia coliO157:H7, Salmonella enterica, and Cronobacter sakazakii in Powdered Infant Formula

Bacterial pathogens such as Listeria monocytogenes, Escherichia coli O157:H7, Salmonella enterica, and Cronobacter sakazakii have demonstrated long-term survival in/on dry or low-water activity (aw) foods. However, there have been few comparative studies on the desiccation tolerance among these bacterial pathogens separately in a same food matrix. In the present study, the survival kinetics of the four bacterial pathogens separately inoculated onto powdered infant formula as a model low-aw food was compared during storage at 5, 22, and 35°C. No significant differences in the survival kinetics between E. coli O157:H7 and L. monocytogenes were observed. Salmonella showed significantly higher desiccation tolerance than these pathogens, and C. sakazakii demonstrated significantly higher desiccation tolerance than all other three bacteria studied. Thus, the desiccation tolerance was represented as C. sakazakii > Salmonella > E. coli O157:H7 = L. monocytogenes. The survival kinetics of each bacterium was mathematically analyzed, and the observed kinetics was successfully described using the Weibull model. To evaluate the variability of the inactivation kinetics of the tested bacterial pathogens, the Monte Carlo simulation was performed using assumed probability distribution of the estimated fitted parameters. The simulation results showed that the storage temperature significantly influenced survival of each bacterium under the dry environment, where the bacterial inactivation became faster with increasing storage temperature. Furthermore, the fitted rate and shape parameters of the Weibull model were successfully modelled as a function of temperature. The numerical simulation of the bacterial inactivation was realized using the functions of the parameters under arbitrary fluctuating temperature conditions.

계란의 유통 중 품질예측을 위한 품질지표 선정

This study was conducted to identify quality indicators of the freshness of chicken eggs circulating in domestic markets. We first stored freshly-laid eggs at temperatures of 0, 10, 20, and 30°C, investigated their weight-loss rate, specific gravity, color, york index, albumen index, Haugh unit (HU), pH, and sensory evaluation, and finally analyzed the correlation between each quality characteristic and the sensory preference. At all the storage temperatures, the quality characteristics of the weight-loss rate, specific gravity, yolk index, albumen index, and HU showed significant correlations (p&lt;0.05) with the preference. In particular, the temperature-dependent correlation between the quality characteristics and the sensory preference was significantly higher with increasing storage temperatures and weight-loss rates (r = -0.78; r = -0.93; r = -0.95; and r = -0.99), albumen index (r = 0.66; r = 0.89; r = 0.89; and r = 0.93), and HU values (r = 0.64; r = 0.92; r = 0.96; and r = 0.98) at 0, 10, 20, and 30°C, respectively (p&lt;0.01). The Color and pH examinations yielded disparate results, and further research is needed to determine the methods of using the characteristics as quality indicators. We believe that the changes in the weight-loss rate, specific gravity, yolk index, albumen index, and HU are adequate quality indicators of the freshness of egg in circulation.

The effect of long-term storage on the quality of sterilized processed cheese.

The aim of this work is to evaluate the effect three different storage temperatures (6, 23 and 40°C) on the sterilized processed cheese quality during 24-month storage. Sterilized processed cheese (SPC) is a product with extended shelf life (up to 2years). The samples of SPC were subjected to basic chemical analyses, i.e. pH-values, dry matter, fat, crude protein and ammonia content, and microbiological analyses, i.e. total number of microorganisms, number of coliforms, colony forming units of yeasts and/or moulds and spore-forming microorganisms. Furthermore, amino acid content (ion-exchange chromatography), protein profile (SDS-PAGE) and fat globules size (image analysis of microscopic technique) were monitored and sensory analysis (scale test and pair comparative test) was implemented, too. Increasing storage temperature and length evoked decrease of total amino acid content and protein nutrition value, increase of ammonia amount, protein changes, enlargement of fat globule size and deterioration of sensory properties of SPC. All the changes grew expressive with increasing storage temperature and time.

Quantifying lycopene synthesis and chlorophyll breakdown in tomato fruit using remittance VIS spectroscopy

The aim of this study was to increase the understanding of chlorophyll breakdown and lycopene synthesis at a quantitative level in Solanum lycopersicum fruit. To accomplish this, a kinetic model is proposed describing the transition from chloro- to chromoplast. Remittance VIS spectroscopy was used to assess chlorophyll and lycopene levels non-destructively in cocktail and round type tomatoes. Tomatoes were stored at constant temperatures between 4 and 24°C, or at a stepwise changing temperature between 4 and 16°C. Chlorophyll and lycopene levels were measured repeatedly over time and used to calibrate a kinetic model that describes how an autocatalytic enzyme system links chlorophyll breakdown to lycopene synthesis, including breakdown of lycopene precursor and lycopene itself. Increasing storage temperatures increased the reaction constant for lycopene synthesis more than that of chlorophyll breakdown for both tomato types. The reaction constants describing chlorophyll breakdown and lycopene synthesis were considerably larger, and the estimated enzyme levels lower for the round type. This allows round tomatoes to quickly resume lycopene synthesis after a cold storage period when enzyme levels are low. Lycopene breakdown was established for the round type while the cocktail type showed lycopene precursor breakdown. Chlorophyll breakdown and lycopene synthesis, as affected by storage temperature and tomato type, is covered well by the model for both tomato types. We hypothesise that the postulated enzyme system, responsible for the direct link between chlorophyll breakdown and lycopene synthesis, is due to STAY-GREEN proteins. Remittance VIS spectroscopy is, in combination with a parameter estimation tool, suited to screen tomato genotypes for intended colour transformation performance, or as tool in chloroplast to chromoplast transition studies.

The Effects of Storage Temperature on the Growth of Vibrio parahaemolyticus and Organoleptic Properties in Oysters.

During harvesting and storage, microbial pathogens and natural spoilage flora may grow, negatively affecting the composition and texture of oysters and posing a potential health threat to susceptible consumers. A solution to these problems would mitigate associated damaging effects on the seafood industry. The purpose of this study was to investigate the effects of storage temperature on growth of vibrios as well as other microbial, sensory, and textural characteristics of post-harvest shellstock Eastern oysters (Crassostrea virginica). Oysters harvested from the Chesapeake Bay, Maryland, during summer months (June, July, and August, 2010) were subjected to three storage temperatures (5, 10, and 20°C) over a 10-day period. At selected time intervals (0, 1, 3, 7, and 10 days), two separate samples of six oysters each were homogenated and analyzed for pH, halophilic plate counts (HPC), total vibrios, and Vibrio parahaemolyticus (Vp). Oyster meats shucked after storage were also organoleptically evaluated (acceptability, appearance, and odor). Texture analysis was performed using a texture analyzer on meats shucked from oysters held under the same conditions. The pH of the oyster homogenates showed no consistent pattern with storage time and temperature. The HPC (4.5–9.4 log CFU/g) were highest on day 7 at 20°C while olfactory acceptance reduced with time and increasing storage temperatures. The Vp counts increased over time from 3.5 to 7.5 log MPN/g by day 10. Loss of freshness as judged by appearance and odor was significant over time (p < 0.05). Toughness of oysters increased with storage time at 5 and 10°C from days 1 to 3 but was inconsistent after day 7. The results indicate that the length of storage and temperature had a significant effect on bacterial counts and olfactory acceptance of oysters but had an inconsistent effect on texture.

Enteric and manure-derived methane emissions and biogas yield of slurry from dairy cows fed grass silage or maize silage with and without supplementation of rapeseed

The aim of this study was to investigate the effect of three different dietary strategies on milk production and composition, enteric CH4 emissions, slurry storage losses of CH4 and total emissions of CH4 with and without biogas production. Fifty-four cows were allocated to three diets according to parity and days in milk. Two diets were based on maize silage with (MS+) or without (MS−) supplementation of crushed rapeseed, and the third diet was based on late cut grass silage without supplementation of crushed rapeseed (GS−). Dry matter intake, milk yield and composition were measured. Enteric methane emissions were measured on 24 cows by means of indirect calorimetry. Slurry was collected the last 10 days of the experiment. Ultimate biogas yield, CH4 emissions at different storage temperatures and yield in a thermophilic biogas digester were determined for the three slurries. Dry matter intake was 22.5kg/day on MS− and MS+ which was significantly higher than the 20.7kg/day on GS−. Yield of energy corrected milk (ECM) was 2.8 and 2.5kg higher on MS+ compared with GS− and MS−, respectively. Enteric CH4 emissions related to dry matter intake or gross energy intake were highest for GS−. Supplementation of crushed rapeseed did not affect enteric CH4 emissions. Ultimate biogas yield and yield of CH4 in the digester were higher for MS+ and MS− than for GS−. Storage emissions from slurry increased with increasing storage temperature. The average total CH4 per kg ECM for the three treatments (mean±standard deviation) was 25.3±2.5, 26.8±3.3 and 29.0±4.2L CH4/kg ECM if manure was stored at 10°C, 15°C or 20°C, respectively. When the slurry was digested in a laboratory scale biogas plant, the lowest total CH4 emissions per kg ECM were observed for MS+ (20.5L CH4/ECM) and the highest for GS− (24.3L CH4/ECM) corresponding to the enteric emissions of CH4. It was found that MS+ had a higher yield and a lower milk fat concentration than MS− and GS−. Although MS+ had a lower milk fat concentration, the ECM yield was significantly higher for MS+ than for the two other diets. It was furthermore concluded that feed ration induced reductions in enteric methane emissions might be counteracted or complemented by changed methane emissions from slurry storage. The slurry biogas yield was highest (per kg ECM) from cows fed MS+ which also gave the lowest total methane emissions per kg ECM.

Participation of GA3, ethylene, NO and HCN in germination of Amaranthus retroflexus L. seeds with various dormancy levels

Amaranthus retroflexus seeds were dormant at 25 °C in the darkness and in the light, and also at 35 °C in the darkness. GA3 and ethylene partially removed dormancy at 35 °C in the darkness and at 25 °C in the light. Dormancy was removed by 1–5 days of treatment with nitric oxide or cyanide. The effect of NO and HCN was inhibited by cPTIO, thus the effect of HCN was NO dependent. Dry storage for 16 weeks could partially release dormancy only at 35 °C, but not at 25 °C. Dry storage increased the response to light, GA3 and ethylene. The response to GA3 and ethylene at 25 °C was enhanced with increasing storage temperature. GA3, ethylene and nitric oxide could substitute dry storage and stratification in partially dormant seeds.

Stability and loss kinetics of lutein and β-carotene encapsulated in freeze-dried emulsions with layered interface and trehalose as glass former

Dehydration and subsequent storage of food materials may result in physicochemical changes and losses of bioactive substances. The purpose of the present study was to determine the stability and loss kinetics of carotenoids in dehydrated emulsions, and to compare the ability of freeze dried single-layer (SL) and layer-by-layer (LBL) emulsions with trehalose as wall material to protect the carotenoids. WPI (2%, w/w, in oil) was used as an emulsifier and homogenised with sunflower oil containing β-carotene (0.05%, w/w) and lutein (0.05%, w/w). Gum Arabic was added to obtain LBL emulsion. Trehalose (20%, w/w) was used as the wall material. Citric acid solution (10%, w/w) was used to adjust the pH of emulsions to pH3.5. The emulsions were then freeze-dried, humidified at 33% RH, stored at low oxygen (25°C, 37°C and 45°C) in closed containers, and analysed using HPLC with C30 column and photodiode-array detector. The loss of lutein and all-trans-β-carotene followed first order kinetics and was more rapid in the SL system compared to the LBL system. Carotenoid losses increased with increasing storage temperatures especially in the SL systems. The activation energy of all-trans-β-carotene in SL was 62.1kJ/mol compared to 43.9kJ/mol in LBL and 58.9kJ/mol in SL compared to LBL with 45.9kJ/mol for lutein. The total β-carotene retention upon storage for 70days was higher in LBL at all storage temperatures. However, the utilisation of LBL increased isomerisation. LBL gave better protection towards carotenoid losses during storage and is highly applicable to formulated materials to control the stability of oil soluble bioactive components.