Soluble Nitrogen Fractions Research Articles

Optimizing irrigation and nitrogen management improves soil soluble nitrogen pools and reduces nitrate residues in a drip-fertigated apple orchard on the Loess Plateau

Appropriate water and nitrogen fertilizer management is crucial for achieving sustainable development in the apple industry. However, the soil nitrogen supply capacity and residual nitrate characteristics under drip fertigation remain poorly understood. Therefore, this study aims to (1) investigate the coupling effects of irrigation and nitrogen levels on the concentrations and distribution characteristics of soil soluble nitrogen fractions and residual soil nitrate; (2) explore the relationships between Christiansen uniformity coefficient (CU) of soil nitrate and apple yield, water productivity (WPc) and nitrogen use efficiency (nitrogen agronomic efficiency, AEn). The field experiment was conducted in a drip-fertigated apple orchard starting in 2017, which included two irrigation levels, 85% (W1) and 100% (W2) of field capacity (FC), and four nitrogen rates, 0 (N1), 120 (N2), 240 (N3) and 360 (N4) kg ha–1. The results showed that nitrogen inputs significantly increased soil soluble inorganic nitrogen and soluble organic nitrogen (SON) contents. However, the SON content significantly decreased when 360 kg N ha–1 was applied, particularly at W1. The maximum nitrate accumulation in the 0–3 m soil layer at N4 reached 2540.97 kg ha–1 in 2021, but the maximum value decreased to 1251.62 kg ha–1 in 2022 due to extreme rainfall. The average CU of residual nitrate across irrigation levels in the 0–3 m soil layer was highest at N3, with values of 0.68 and 0.57 in 2021 and 2022, respectively. High irrigation level increased the diffusion distances of nitrate both vertically and horizontally, resulting in a significant effect on CU. Apple yield and WPc first increased and then decreased with increasing nitrogen rates, while AEn consistently decreased, but they were all greater with a higher CU. The recommended combination of irrigation and nitrogen application was 85% FC and 240 kg N ha–1, which can achieve the dual goals of enhancing soil nitrogen supply capacity and minimizing environmental risks while improving orchard productivity.

Influence of using different ratios of small ruminants (ovine and caprine) milk on compositional and proteolytic changes during ripening of raw milk lighvan cheese

Lighvan cheese was manufactured using different ratios of ovine and caprine milk (100:0, 75:25, 50:50, 25:75, 0:100) and ripened for 90 days. Chemical composition, proteolysis level, total and individual levels of free amino acids, texture and residual coagulant activity were analysed during ripening. Significant decreases in pH and moisture content and significant increases in texture parameters, residual coagulant activity, soluble nitrogen fractions, fat, and protein contents were determined in the cheese manufactured using higher ratios of ovine milk (P <0.05). Differences in gel electrophoresis and RP-HPLC peptide profiles of the cheeses were seen. Leu and Phe were detected as predominant free amino acids in the cheeses during ripening. In conclusion, besides the cheese manufactured using ovine milk alone, the lighvan cheeses made with ovine and caprine milk in the ratios of 75:25 and 50:50 can be introduced as the preferred cheeses because of having proper proteolysis indices and semi-hard texture.

Biochar from animal manure: A critical assessment on technical feasibility, economic viability, and ecological impact

AbstractAnimal manure has been used to manage soil fertility since the dawn of agriculture. It provides plant nutrients and improves soil fertility. In the last decades, animal husbandry has been significantly expanded globally. Its economics were optimized via the (international) trade of feed, resulting in a surplus of animal manure in areas with intensive livestock farming. Potentially toxic elements (PTEs), pathogenic microorganisms, antibiotic residues, biocides, and other micropollutants in manure threaten animal, human, and environmental health. Hence, manure application in crop fields is increasingly restricted, especially in hotspot regions with intensive livestock activities. Furthermore, ammonia volatilization and greenhouse gas (GHG) emissions during manure storage, field application, and decomposition contribute to air pollution and climate change. Conventional manure management scenarios such as composting and anaerobic digestion partially improve the system but cannot guarantee to eliminate sanitary and contamination risks and only marginally reducing its climate burden. Hence, this review discusses the potential of pyrolysis, the thermochemical conversion under oxygen‐limited conditions as an alternative treatment for animal manure providing energy and biochar. Manure pyrolysis reduces the bioavailability of PTEs, eliminates pathogenic microorganisms and organic micropollutants, and reduces GHG emissions. Pyrolysis also results in the loss of nitrogen, which can be minimized by pretreatment, that is, after removing soluble nitrogen fraction of manure, for example, by digestion and stripping of ammonia–nitrogen or liquid–solid separation. However, conclusions on the effect of manure pyrolysis on crop yield and fertilization efficiencies are hampered by a lack of nutrient mass balances based on livestock unit equivalent comparisons of manure and manure biochar applications. Hence, it is essential to design and conduct experiments in more practically relevant scenarios and depict the observations based on the amount of manure used to produce a certain amount of biochar.

Effects of milk types used in Antep cheese production on some cheese organoleptic quality parameters and brine composition during 5‐month ripening

Antep cheese is a local Turkish cheese characterized by scalding during production and ripened in brine. In this study, Antep cheeses were produced using mixtures of different milk types (cow, sheep, and goat milk) and ripened for 5 months. The composition, proteolytic ripening extension index (REI), free fatty acid (FFA) content, and volatile compounds of the cheeses and the variation of the brines were analyzed for the 5-month ripening period. Low proteolytic activity in cheese during ripening caused the cheeses to have low REI values (3.92%-7.57%), although it was observed that some parts of the water-soluble nitrogen fractions diffused into the brine, causing a lower REI. As a result of lipolysis during ripening, total FFA (TFFA) concentrations in all cheeses were increased, whereas the highest increases were detected in the concentrations of short-chain FFAs. The highest FFA concentrations were determined in cheese produced using goat milk, and the volatile FFA ratio in TFFA exceeded 10% in the third month of ripening. Although it was observed that the milk types used in the production had significant effects on the change of volatile compounds of the produced cheeses and their brines, the impact of the ripening time was more important. PRACTICAL APPLICATION: This study investigated Antep cheese made with different milk types. Volatile compounds and soluble nitrogen fractions were transferred to the brine by diffusion during ripening. The volatile profile of the cheese varied with milk type, but ripening time was the primary factor influencing volatile compounds. This suggests that the targeted organoleptic properties of the cheese are determined by ripening time and conditions. Additionally, changes in the brine's composition during the ripening process provide insight into how to manage the brine as waste.

Upgrading ammonia-nitrogen from manure into body proteins in black soldier fly larvae

Nitrogen (N) losses via ammonia (NH3) emissions from manure is one of the main environmental burdens resulting from livestock production. Feeding manure to black soldier fly larvae (BSFL) is envisioned as a new circular strategy to recover manure-N, reduce its environmental impact, and upgrade it into insect proteins to be used in animal feed. However, so far, it remained unknown if BSFL could incorporate N from NH3 in manure into the larval body mass. Here, using the stable isotope 15N in NH3, we demonstrate that at least 13% of pig manure NH3-N can be incorporated into BSFL body mass. Within the larval body, the tracer was found in both insoluble and soluble nitrogen fractions, including proteins. We discuss interventions that could increase the incorporation of NH3-N into larval proteins and with that reduce NH3 emissions from manure. Our results provide the first reliable quantification of NH3-N assimilation in manure-fed larvae and contributes to quantifying the potential of BSFL for manure management, and as a circular protein source.

Dynamic modeling of a full-scale membrane bioreactor performance for landfill leachate treatment.

Leachate treatment is crucial in landfill management. As landfill ages, inert constituents and ammonia nitrogen concentration in leachate increases, which results in a decrease in biological treatability. In this study, a full-scale MBR treating leachate was dynamically modeled using ASM1. The investigated landfill has been serving for more than 25years; thus, a decrease in biodegradable organic content and an increase in nitrogen content of the leachate is expected in the years ahead. The calibrated model predicted MLSS, effluent COD, and effluent TN concentrations with high accuracy. Following the calibration study, it was found that soluble inert COD and soluble inert organic nitrogen fractions were the primary reasons ofhigh COD and TKN concentrations in the effluent, respectively. The validated model of the full-scale MBR system treating leachate can be a useful tool to understand the limitations of the system. Soluble inert constituents of the leachatethat pass through the membranenecessiate additional treatment processesfor discharge into surface water bodies.

Comparison of γ-aminobutyric acid and free amino acid contents of some common varieties of Turkish cheeses

A total of thirty cheese samples belonging to three varieties (Beyaz, Kasar and Tulum) with different technological traits were analysed for gamma-aminobutyric acid (GABA) and free amino acid (FAA) content. Microbiological and physicochemical status and soluble nitrogen fractions of cheese samples were examined to determine their effects on formation of GABA during ripening. The major FAA were His, Ile, Lys for Beyaz cheeses, Glu, His, Tyr, Ile, Phe, Trp for Kasar cheeses and His, Arg, Tyr, Ile, Leu, Trp for Tulum cheeses. Also, total free amino acid content was higher in Tulum cheeses. The GABA concentration ranged from 0.00 to 83.05 mg 100 g−1, 1.65–45.79 mg 100 g−1 and 0.20–21.06 mg 100 g−1 for Beyaz, Kasar and Tulum cheeses, respectively. Cheese microflora, soluble nitrogen fractions, amino acid concentrations such as Glu and Gln and ripening time/conditions had a significant effect on formation of GABA.

Effect of Ripening in Brine and in a Vacuum on Protein, Fatty Acid and Mineral Profiles, and Antioxidant Potential of Reduced-Fat White Cheese.

SUMMARYResearch backgroundNumerous factors affect the ripening of reduced-fat white cheese. The aim of this study is to investigate the influence of ripening environment (brine or vacuum plastic bags without brine) on the chemical composition, protein, fatty acid profile and mineral content as well as antioxidant properties of industrially produced reduced-fat white cheese.Experimental approachA low-fat white cheese was manufactured on an industrial scale from milk that remained after the production of kajmak and ripened for 60 days at 4 °C after packaging in a polystyrene container with brine containing 6% salt or in vacuum-sealed polyethylene bags. The influence of ripening environment on proteolysis was monitored by the change of soluble nitrogen fractions as well as by sodium dodecyl sulphate–polyacrylamide gel electrophoresis of tris(hydroxymethyl) aminomethane-HCl extracts of cheese proteins under non-reducing conditions and water-soluble fractions under reducing conditions. An effect that ripening environment had on fatty acid and mineral content was also monitored. The change of antioxidant potential of the investigated cheese during ripening led to the change of iron(II) chelating ability, reducing power and free-radical scavenging activity.Results and conclusionsThe ripening environment differently affected proteolysis, fatty acid composition, mineral profile and antioxidant properties of reduced-fat white cheese. White cheese ripened in brine had more intensive proteolytic changes than the cheese ripened in a vacuum, but also more intensive diffusion processes, especially between the 40th and 60th day of ripening. The brine-ripened cheese had higher values of water-soluble nitrogen content, but lower contents of trichloroacetic acid-soluble and phosphotungstic acid-soluble nitrogen than the vacuum-ripened cheese. Cheese ripened in brine had a lower content of almost all investigated macro- and microelements. After 60 days of ripening, in cheese ripened in brine only myristic (C14:0) and palmitic acid (C16:0) were detected, whereas in the vacuum-ripened cheese C10:0-C16:0 fatty acids dominated. Vacuum-ripened reduced-fat cheese had more favourable reducing power, while white brined reduced-fat cheese had better radical scavenging activity and iron(II) chelating activity.Novelty and scientific contributionThese results suggest significant influence of ripening conditions (immersion in brine or in vacuum-sealed polyethylene bags) on nutritive and functional properties of reduced-fat white cheese. Ripening in a vacuum has become a useful method for obtaining high-value reduced-fat white cheese.

Quark-Type Cheese: Effect of Fat Content, Homogenization, and Heat Treatment of Cheese Milk.

The effect of homogenization and fat reduction in combination with variable heating conditions of cow milk on the characteristics of Quark-type cheese were investigated. The mean composition of full-fat cheeses was 71.96% moisture, 13.95% fat, and 10.31% protein, and that of its reduced-fat counterparts was 73.08%, 10.39%, and 12.84%, respectively. The increase of heat treatment intensity increased moisture retention and improved the mean cheese protein-to-fat ratio from 0.92 to 1. Homogenization increased the moisture and protein retention in cheese, but the effect was less intense for milk treated at 90 °C for 5 min. The extended denaturation of whey proteins resulted in harder, springier, and less cohesive cheese (p < 0.05). Treatment of milk at 90 °C for 5 min resulted in higher residual lactose and citric acid and lower water-soluble nitrogen contents of cheese (p < 0.05); the latter was also true for homogenization (p < 0.05). Storage did not affect the composition and texture but decreased galactose and increased citric acid and soluble nitrogen fractions (p < 0.05). In conclusion, heat treatment conditions of milk that induced a considerable denaturation of β-lactoglobulin and left a considerable amount of native α-lactalbumin was adequate for the manufacture of a “clean-label” Quark-type cheese, whereas homogenization was more effective for full-fat cheese.

Semi-Industrial Production of Kashkaval of Pindos Cheese Using Sheep or a Mixture of Sheep-Goat Milk and the Utilization of the Whey for Manufacturing Urda Cheese.

Kashkaval of Pindos cheese was successfully produced using 100% sheep milk (KS) or with the addition of 10% goat milk (KG). Urda cheese was manufactured using 100% sheep (US) or 90% sheep–10% goat (UG) whey from the production of kashkaval of Pindos cheese. Both cheeses were made taking into account their traditional cheese-making methods. The cheeses were assessed for their chemical, microbiological and organoleptic characteristics. Generally, no significant differences were observed between KS and KG cheese and between US and UG cheese regarding their physicochemical, textural characteristics, soluble nitrogen fraction and total fatty acid content. The fat content of Urda cheese was low, in accordance with the demand of consumers for healthy products. KS cheeses showed higher total volatile compounds than KG cheeses at 60 and 90 days of ripening and storage as well as lower counts of thermophilic–mesophilic lactic acid bacteria. No differences were observed in the microbial counts between US and UG cheeses. Acetone, hexanal, 2 heptanone, ethanol and toluene were found in abundance in Urda cheeses. Both kashkaval of Pindos and Urda cheeses received high scores during the organoleptic evaluation. The obtained data may lead to the production of both cheeses with standard characteristics according to the traditional recipes and improve their recognition.

BIOCHEMICAL STUDIES ON THE EFFECT OF SOME BIOFERTELIZERS ON SOYBEAN SHOOTS

The field excrement was conducted in the agronomy farm of Gazala, Sharkia, Egypt to study the effect of power mix, citrine and super blue green biofertilizers on some biochemical contents of soybean shoots of (Giza111 and Crawford) varieties. The following results were recorded: - 1- All doses of biofertilizers increased dry weight content of shoots to both varieties of soybean. Giza111 variety recorded relatively greater values than those of Crawford variety. 2- The concentration of chl. a, chl. b and total chl. Of shoots soybean were increased by all treatments while decreased the concentration of carotenoids in shoots only at early stages of Giza111 variety, but increased of crawford variety at all stages of growth. 3- The percentage of total soluble sugars (reducing and non-reducing) in shoots of crawford variety were greater than those of giza111 variety and the highest increase of total soluble sugars was obtained by the foliar application of 0.25% and 0.5% super blue green biofertilizers. 4- All treatments were increased the concentration of soluble, insoluble and total nitrogen fractions in both varieties of soybean shoots at all stages of growth. 5- All doses of biofertilizers decreased the concentration of Na in shoots of both varieties of soybean, while they were increased the concentration of P and K at all stages of growth. 6- Fe, Zn and Mn contents were slightly increased by the application of biofertilizers at the early and second stage of growth, while they decreased values at the late stage of shoots growth. Conclusively, from the current results, it can be noticed that the application of all biofertilizers increased dry weight, photosynthetic pigments (chl. a, chl. b and carotenoids), the percentage of total nitrogen were increased either with all doses of biofertilizers in both varieties of soybean (Giza111 and Crawford). the highest increase of total soluble sugars was obtained by the foliar application of 0.25% and 0.5% super blue green biofertilizers especially in Giza111 variety. All micro and macro elements were increased (Na, K, P, Fe, Zn, Mn) except Na on all soybean vaterites.

Humic acid as a biotechnological alternative to increase N-NO3- or N-NH4+ uptake in rice plants

Abstract The aim of this work was to evaluate the vermicompost humic acid (HA) stimulatory effects on the N-uptake kinetics and the N metabolism of rice plants under high and low N-NO3- or N-NH4+ supply in nutrient solution. Plants were grown in a growth chamber, and at 21 days after germination, they were submitted to N deprivation for 96 h, followed by HA treatment or no treatment. After 96 h of N deprivation, the plants received 0.2 or 2.0 mmol L−1 N-NO3- or N-NH4+. Changes in pH, NO3- or NH4+ net influx, fresh weight, soluble nitrogen fractions and sugars in both the roots and shoots were evaluated. Pretreatment of rice plants with HA stimulated NO3- uptake, preserved plant metabolic status and increased fresh weight. On the other hand, plants submitted to N-NH4+ facilitated the accumulation of this N form, promoting symptoms of toxicity and leading to a reduction in fresh weight. The results suggest that HA pretreatment modifies the net influx of NO3- or NH4+, which cause differences in plant physiology. Vermicompost humic acids could be part of biotechnology packages for the purpose of increasing the nitrogen nutrition of rice plants.

Evaluation of physicochemical characteristics of microwave vacuum dried mackerel and inhibition of oxidation by essential oils.

In the present study, Indian mackerel was dried by microwave vacuum drying (MVD) method and compared its physico chemical quality to mackerel dried by hot air drying (HAD) method. Antioxidant effects of thyme oil (TMO) and clove leaf oils (CLO) during storage were also evaluated. Brine salted mackerel was dried in hot air oven (50-55°C) and microwave vacuum dryer (600W and 600Hgmm). For essential oil treatment, mackerel was dipped in 0.75% TMO and CLO for 5min. Moisture content of MVD and HAD samples was reduced to 30-32% in 1.2h and 12h, respectively. Rehydration ability and water absorption index of MVD samples were significantly higher to that of HAD samples. Mackerel dried by HAD showed significantly higher salt soluble and water soluble protein nitrogen fractions than that of MVD samples. Significantly higher hardness and chewiness values were observed for HAD samples. Color and appearance of uncooked MVD sample was superior to that of HAD samples. As per the results of PV and TBARS, TMO exhibited better antioxidant effect compared to CLO. The study demonstrated that fast drying can be achieved by microwave vacuum dryer and it can produce dried fish having better sensory and textural attributes.

Development of nutrient-rich growing media with hazelnut husk and municipal sewage sludge

ABSTRACTThe aim of the present study was to develop structurally stable, nutrient-rich and environmentally safe growing media by combining waste material: crop residue hazelnut husk (HH) and municipal sewage sludge. In order to achieve this goal, lignocellulosic HH residue was mixed with nutrient-rich sewage sludge (S) in various proportions: HH 100%; HH + S1 87.5% : 12.5%; HH + S2 75% : 2 5%; HH + S3 50% : 5 0%. Following composting, the key physical, chemical and microbiological properties of the growing media were characterized for long-term ornamental nursery crops. The addition of S to the mixture had both significant detrimental and remedial effects on physical properties such as reduced total porosity and water-holding capacity, whilst improved the air capacity, wettability and shrinkage. S content of growing media significantly enriched the plant nutrients, especially the most desired soluble and organic nitrogen fractions and micro nutrients. Germination tests and microbiological analysis confirmed the products as environmentally safe ornamental growing media. We conclude that composting of HH with S is a viable alternative for the development of nutrient-rich growing media and recycling of such waste in the ornamental industry could be a beneficial method in order to sustain waste management and crop production.

In situ and in vitro evaluations of a slow release form of nitrate for ruminants: Nitrate release rate, rumen nitrate metabolism and the production of methane, hydrogen, and nitrous oxide

In situ and in vitro experiments were conducted to determine nitrate (NO3−) release rate from encapsulated NO3− (EN) in the rumen and to examine metabolism of EN-NO3− in conjunction with methane (CH4), hydrogen (H2), and nitrous oxide (N2O) production. Three ruminally-cannulated beef heifers were used to incubate the following substrates in the rumen for 72h: soybean meal, EN, and unencapsulated NO3− (UEN). Because of immediate solubilisation, soluble nitrogen (N) fraction of UEN was assumed to be 100%. A non-linear regression model fitted to N disappearance of EN (R2=0.93, P<0.01) indicated 35.4% of soluble N fraction and 54.7% of slowly degradable N fraction. Two in vitro experiments were conducted where UEN and EN were incubated for 24h in buffer alone without substrate or in buffered-rumen fluid with substrates containing starch and xylan with urea, UEN, or EN as sole N sources. When UEN was incubated with buffer, 99.9% of UEN-NO3−-N was recovered as NO3−-N in the buffer over 24h. However, recovery of EN-NO3− as NO3−-N gradually increased over 24h up to 58%. When urea, EN or UEN were incubated with buffered-rumen fluid, total gas production decreased (P=0.022) for UEN compared with urea and EN. Methane production decreased (10.7 and 13.3 vs. 19.6mL; P<0.01) for UEN and EN, respectively, compared with urea. Hydrogen production considerably increased (P<0.01) for UEN compared with urea and EN without a difference between urea and EN. Nitrous oxide production was greater for UEN followed by EN and urea (20.8, 7.5 and 0.02μL, respectively; P <0.05). During the incubation with buffered-rumen fluid, 100% of UEN-NO3− was recovered as NO3−-N in the medium until 6h and then the recovery gradually decreased to 18% at 24h while recovery as NO2−-N increased up to 22% at 24h. However, recovery of EN-NO3−-N as NO3−-N in the medium increased by 20% at 12h and then gradually decreased to 5% at 24h without accumulation of NO2−-N in the medium. In conclusion, EN released NO3− slowly in the rumen and decreased CH4 production without negatively affecting microbial fermentation. Increases in H2 and N2O production and accumulation of NO3− and NO2− in the medium were not observed for EN compared with UEN, indicating that EN could be a promising NO3− source to lower CH4 production with less risk of NO3−/NO2− toxicity.

Proteolytic Activity and Production of γ-Aminobutyric Acid by Streptococcus thermophilus Cultivated in Microfiltered Pasteurized Milk

A set of 191 strains of Streptococcus thermophilus were preliminarily screened for the presence of the genes codifying for cell envelope-associated proteinase (prtS) and for glutamate decarboxylase (gadB) responsible for γ-aminobutyric acid (GABA) production. The growth and proteolytic activity of the gadB-positive strains (9 presenting the prtS gene and 11 lacking it) were studied in microfiltered pasteurized milk. Degradation of both caseins (capillary electrophoresis) and soluble nitrogen fractions (HPLC) and changes in the profile of free amino acids (FAAs; ion-exchange chromatography) were evaluated at inoculation and after 6 and 24 h of incubation at 41 °C. None of the strains was capable of hydrolyzing caseins and β-lactoglobulin, and only two hydrolyzed part of α-lactalbumin, these proteins being present in their native states in pasteurized milk. Contrarily, most strains were able to hydrolyze peptones and peptides. For initial growth, most strains relied on the FAAs present in milk, whereas, after 6 h, prtS+ strains released variable amounts of FAA. One prtS+ strain expressed a PrtS- phenotype, and two prtS- strains showed a rather intense proteolytic activity. Only five strains (all prtS+) produced GABA, in variable quantities (up to 100 mg/L) and at different rates, depending on the acidification strength. Addition of glutamate did not induce production of GABA in nonproducing strains that, however, unexpectedly were shown to adopt the degradation of arginine into citrulline and ornithine as an alternative acid resistance system and likely as a source of ATP.

Plasmin and coagulant activities in a minicurd model system: Study of technological parameters

The effect of scalding temperature of the curd, the inclusion of a washing step, and the pH at whey drainage on plasmin and coagulant activities were assessed in a minicurd model of young hard cooked cheese. The variables were tested as follows: draining pH was assayed at 3 levels (4.6, 5.6, and 6.4), curd scalding temperature was tested at 50 and 56°C, and washing of the curd was examined at 2 levels (no washing step, and the replacement of the whey by water). Increase in pH at whey drainage and washing of the curd had a positive effect on plasmin activity, which was also evidenced by compatible changes in soluble peptide profiles. No effect of increased cooking temperature was found on plasmin activity. Plasminogen activation was not verified in any treatment. As for coagulant, lower pH values at whey drainage and a decrease in curd cooking temperature increased its activity; washing of the curd showed no influence on coagulant residual activity. These results were consistent with proteolysis described by peptide profiles, electrophoresis, and soluble nitrogen fractions.

Non-destructive measurement of nitrogen status of leafy ornamental cuttings by near infrared reflectance spectroscopy (NIRS) for assessment of rooting capacity

An adequate nitrogen supply to stock plants is a well-known key factor in adventitious root formation of herbaceous ornamental cuttings. Both slight deficiency and luxury amount of nitrogen in the tissue can impair rooting. Due to a lack of fast, cheap and reliable analytical methods, parameters characterising the nitrogen status of cuttings are not used as quality indicators. Near infrared reflectance spectroscopy (NIRS) might bridge this gap, especially if sample preparation such as drying or grinding is avoided. NIR spectra of intact chrysanthemum and pelargonium cuttings were taken and partial least square regression models were developed for various nitrogen fractions as well as for total nitrogen. Calibration equations with high prediction performance were developed for insoluble, organic and total nitrogen (R2 > 0.8). Calibration models for various soluble nitrogen fractions were at least suitable for a rough screening (R2 > 0.6). In a second experiment, calibration models were extended to poinsettia, impatiens and osteospermum cuttings by adding a few samples to the calibration data set. Thus, analysing nitrogen status of ornamental cuttings by NIRS might be a valuable tool for optimisation of stock plant cultivation and assessment of rooting capacity of cuttings.

Characterization of goat milk from Lebanese Baladi breed and his suitability for setting up a ripened cheese using a selected starter culture

In this work the hygiene and quality parameters of goat milk from Baladi breeds were assess in order to evaluate his suitability for setting up a ripened cheese. Experimental cheese trials were performed on local Lebanese dairy farm using a selected culture starter. Evolution of physicochemical and microbiological features of experimental cheese during ripening were evaluated. Raw milk showed a good microbiological quality meeting the hygiene criteria given by European law on the hygiene of foodstuffs. Mesophilic lactobacilli were found to predominate during cheese fermentation while thermophilic cocci gradually grown and were preponderant during all ripening stage. Non-protein nitrogen and water soluble nitrogen fractions increased gradually over the ripening highlighting good casein primary proteolysis. The Free Fatty Acids (FFA) content increased through the ripening period reaching 7340mg/100g. Palmitic and oleic acids were the most representative long-chain FFAs at 210days whereas capric acid was found as a major short-chain FFA. Cheese ripened 90 days, revealed high score for the flavor and taste attributes and good globally acceptance.

Characterisation of Urda whey cheese: Evolution of main biochemical and microbiological parameters during ripening and vacuum packaged cold storage

In this study, the main biochemical and microbiological characteristics of Urda, a traditional Greek whey cheese, were determined during ripening at 19 ± 2 °C for 25 days followed by vacuum packaging and storage at 5 °C until day 360. Few differences in pH, water activity, acid degree value, moisture, salt, protein and fat contents were observed between Urda cheeses produced from sheep or goat milk whey at all sampling days (1, 25, 90, 180 and 360). Cheese microbiota was dominated by mesophilic lactic acid bacteria, but high numbers of enterococci, aerobic gram-negative bacteria and Enterobacteriaceae were also present. Increases in all the soluble nitrogen fractions of cheeses occurred, primarily during cold storage. Ketones and terpenes were the most abundant volatile compounds in fresh (1-day) sheep and goat cheeses, respectively, whereas free fatty acids were the most abundant compounds in mature (180-day) cheeses, followed by ketones.