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Uzturs Veselības aprūpe Nutrition Health Care Aktualitāte: Olbaltumvielu saturoši uztura bagātinātāji veido aptuveni 80% no sportistiem paredzēto uzturproduktu apgrozījuma. Sūkalu olbaltumvielu saturošie produkti ir visvairāk patērētie olbaltumvielu saturošie uztura bagātinātāji. Ņemot vērā, ka ar piena produktu sastāvu saistītā krāpšanās ierindojas otrajā vietā pārtikas viltojumu datubāzē, un, apzinoties olbaltumvielu noteikšanas standartmetožu vājās vietas, pēdējo gadu laikā publicēti vairāki pētījumi, kas pēta iespējamās analītiskās ķīmijas metodes, lai atklātu olbaltumvielu saturošo produktu falsifikāciju. Pētījuma mērķis: Analizēt un izvērtēt sportistiem paredzēto sūkalu olbaltumvielu izolātu saturošo produktu sastāvu un uzturvērtību. Pētījums sastāv no trīs daļām: 1. Analizēti septiņu sūkalu olbaltumvielu izolātu saturošu produktu sastāvs un uzturvērtība. 2. Produktiem ar Kjeldāla metodi noteikts kopējais olbaltumvielu saturs produktos. 3. Trijiem sūkalu olbaltumvielu izolātu saturošiem produktiem un vienam sūkalu olbaltumvielu koncentrāta paraugam noteiktas kopējais un brīvo aminoskābju daudzums. Kvantitatīvs, eksperimentāls pētījums norisinājās Latvijas Biozinātņu un tehnoloģiju universitātes Pārtikas tehnoloģijas fakultātē. Visi pētījuma rezultāti iegūti divos atkārtojumos. Tika izmantot aprakstošā statistika. Datu apstrādei tika izmantota Microsoft Excel 2019 programma. Datiem noteikts vidējais aritmētiskais, mediāna, moda un standartnovirze. Tika izvirzīta hipotēze, ka SOI-BEZNAS būs zemāks NAA, tostarp SĶAS un DNAS saturs salīdzinājumā ar produktiem, kuriem ir norādīts aminoskābju saturs marķējumā. Rezultāti: Tika konstatēts, ka lielākajā daļā analizēto produktu olbaltumvielu saturs atbilst marķējumā norādītajam daudzumam, Tomēr sestajā paraugā tika konstatēta novirze 10,46 g/100 g, ko izraisīja pievienotās neolbaltumvielu slāpekli saturošas vielas. Trešajā paraugā tika konstatēts par 6,1 % mazāk olbaltumvielu, nekā norādīts marķējumā. Pārējos paraugos tika konstatēta novirze 0,8–3,2 % apmērā. Pētījumā tika konstatēts, ka NAS, SĶAS, DNAS un AAS daudzums SOI-BEZNAS bija ievērojami zemāks nekā šo aminoskābju līmenis standartizētā SOI. Aminoskābju saturs testētajos produktos atšķīrās, iespējams, olbaltumvielu satura un kvalitātes atšķirību dēļ. Brīvo aminoskābju saturs testētajos produktos bija zems, izņemot sesto un trešo produktu, kuros bija relatīvi augstāks brīvo NAS un AAS saturs. Secinājumi: Pētījumā tika konstatēts, ka lielākā daļa SOI produktu atbilst marķējumā norādītajam olbaltumvielu daudzumam, taču neviens no produktiem neatbilst standartizēta SOI kritērijiem. Lai novērstu patērētāju maldināšanu, nepieciešami stingrāki marķēšanas noteikumi un sabiedrības informēšana par atšķirībām starp “SOI” un “SOI saturošiem produktiem”. Šajā pētījumā apstiprinājās arī hipotēze, ka vidēji SOI ar norādītu aminoskābju profilu satur lielāku NAS, tostarp SĶAS un DNAS daudzumu salīdzinājumā ar SOI bez norādīta aminoskābju daudzuma. Background: Protein-based food supplements account for around 80% of the sales of nutritional products for athletes. Among these, whey protein products are the most consumed. Given that dairy-related fraud ranks second in the food fraud database, and recognizing the limitations of standard methods for protein determination, several studies have been published in recent years investigating alternative analytical chemistry methods for detecting protein adulteration. Objective: The purpose of this study was to analyze and evaluate the composition and nutritional value of whey protein isolate products intended for athletes. The study consisted of three parts: 1. The composition and nutritional value of seven whey protein isolate products were analyzed. 2. The total protein content of the products was determined using the Kjeldahl method. 3. Total and free amino acids were determined for three whey protein isolate products and one whey protein concentrate sample. A quantitative, experimental study took place at the Faculty of Food Technology, Latvian University of Biosciences and Technology. All results were obtained in two replicates and data was processed using Microsoft Excel 2019. Descriptive statistics, including the arithmetic mean, median, mode, and standard deviation, were calculated. It was hypothesized that whey protein isolates without stated amino acid profiles would contain lower levels of essential amino acids, including branched chain amino acids and conditionally essential amino acids, compared to those with stated amino acid profiles. Results: The protein content of the majority of the evaluated products was found to be consistent with the amount stated on the label, but the sixth sample showed a deviation of 10.46 g/100 g due to added non-protein nitrogenous substances. The third sample had 6.1% less protein than indicated on the label. The remaining samples showed a deviation of 0.8–3.2%. The study found that the levels of EAAs, BCAAs, CEAA, and NEAAs in SOI-BEZNAS products were significantly lower than in standardized WPI. The amino acid content varied among the products, likely due to differences in protein content and quality. The free amino acid content was low, except for the sixth and third products, which had higher levels of free EAAs and NEAAs. Conclusions: The study found that most WPI products met label protein content claims, but none met criteria for a standardized WPI. Stricter labeling regulations and education about the difference between "WPI" and "WPI-containing products" are needed to prevent consumer confusion. The hypothesis that WPIs with stated amino acid profiles have higher levels of essential amino acids was confirmed.

Our objective was to determine the effects of temperature and protein concentration on viscosity increase and gelation of liquid micellar casein concentrate (MCC) at protein concentrations from 6 to 20% during refrigerated storage. Skim milk (~350 kg) was pasteurized (72°C for 16 s) and filtered through a ceramic microfiltration system to make MCC and replicated 3 times. The liquid MCC was immediately concentrated via a plate ultrafiltration system to 18% protein (wt/wt). The MCC was then diluted to various protein concentrations (6–18%, wt/wt). The highest protein concentrations of MCC formed gels almost immediately on cooling to 4°C, whereas lower concentrations of MCC were viscous liquids. Apparent viscosity (AV) determination using a rotational viscometer, gel strength using a compression test, and protein analysis of supernatants from ultracentrifugation by the Kjeldahl method were performed. The AV data were collected from MCC (6.54, 8.75, 10.66, and 13.21% protein) at 4, 20, and 37°C, and compression force test data were collected for MCC (15.6, 17.9, and 20.3% protein) over a period of 2-wk storage at 4°C. The maximum compressive load was compared at each time point to determine the changes in gel strength over time. Supernatants from MCC of 6.96 and 11.61% protein were collected after ultracentrifugation (100,605 × g for 2 h at 4, 20, and 37°C) and the nitrogen distributions (total, noncasein, casein, and nonprotein nitrogen) were determined. The protein and casein as a percent of true protein concentration in the liquid phase around casein micelles in MCC increased with increasing total MCC protein concentration and with decreasing temperature. Casein as a percent of true protein at 4°C in the liquid phase around casein micelles increased from about 16% for skim milk to about 78% for an MCC containing 11.6% protein. This increase was larger than expected, and this may promote increased viscosity. The AV of MCC solutions in the range of 6 to 13% casein increased with increasing casein concentration and decreasing temperature. We observed a temperature by protein concentration interaction, with AV increasing more rapidly with decreasing temperature at high protein concentration. The increase in AV with decreasing temperature may be due to the increase in protein concentration in the aqueous phase around the casein micelles. The MCC containing about 16 and 18% casein gelled upon cooling to form a gel that was likely a particle jamming gel. These gels increased in strength over 10 d of storage at 4°C, likely due either to the migration of casein (CN) out of the micelles and interaction of the nonmicellar CN to form a network that further strengthened the random loose jamming gel structure or to a gradual increase in voluminosity of the casein micelles during storage at 4°C.

The oil and carbohydrates contained in the Moringa oleifera seeds (MO) are two parameters that inhibit its coagulant potential. Oil extraction and protein purification are therefore necessary to im...

The objective of the research work was to compare the protein content of pollen from some plants visited frequently by honey bees in Bulgarian and Australian flora, and study the length of life of worker honey bees fed by pollen with different protein content. In this study the number of the same floral species, were described nine. Most number of favorite plants for honey bees are from Asteraceae – 5. The percentage of the total protein content in the compared bee-collected pollen grains ranged from: 11.5% for Chondrilla juncea to 25.1% for that of Brassica napus, and the average value was 18.5% for Bulgarian species, and 13.8% for Helianthus annuus to 25.9% for that of Trifolium repens, and the average value was 19.3% for Australian species. It is made a systematic comparison between Bulgarian and Australian protein content in pollen, but significant differences of the two groups were not found. Proteins are one of the the main components of honey bee-collected pollen, and can vary among different pollen plant species source. The very similar results in Bulgarian study compared to the published ones note the conservatism of pollen, despite the very long distance between Bulgaria and Australia, but having in mind if the Australian results come from inside country. It could be said that the honey bees in Bulgaria and Australia consume pollen with the same amount protein content from the same floral species. The length of live of worker bees ranged from 25 days when they consumed pollen from Brassica napus (25.1% protein content) to 14.3 days when they consumed pollen from Zea mays (17%). The present study was performed to make also a systematic comparison between length of life worker bees fed by pollen with different protein content and significant differences were found. The worker honey bees lived longer when they consumed pollen with higher protein content.

Chestnut cultivars grown for high-quality fruits are known as marrons. ‘Lovran Marron’ is the only known traditional Croatian variety of the sweet chestnut. It is grown on private estates in the Lovran surroundings, on the eastern slopes of Mount Učka, where the oldest plantations are several hundred years old. The aim of this study was to compare two methods of nitrogen and protein analysis in ‘Lovran Marron’ fruits. Fruits were collected in October 2019, in the environs of Lovran (Croatia). In order to compare total nitrogen (N) content in marron fruits by the Kjeldahl and dry combustion methods (ISO 13878, 1998), 70 samples of ‘Lovran Marron’ fruits were analyzed. Protein content was calculated by multiplying nitrogen content by factor of 5.30. The Kjeldahl method was performed using Kjeltec 8200 (FOSS, Denmark), using 1 g of grounded raw fruits, previously frozen. The dry combustion method was performed on the NC Soil Flash 2000 Thermo Scientific device (Thermo Fisher Scientific, USA), using 20 mg of grounded and dried raw fruit. Descriptive statistics and analysis of variance were applied to evaluate the differences between the results obtained by these two analytical methods.

Objective: The aim of this study is to determine the total protein and free amino acid content of Artemisia abrotanum L. in two different periods, the pre-blooming and blooming periods.Methods: The Dumas and Kjeldahl methods were applied comparatively to determine the total protein amount. In addition, after the sample was extracted with water:methanol (80:20) containing 0.1% formic acid, free amino acids were determined in liquid chromatography-mass spectrometer.: By using the Dumas method, the % nitrogen content was found to be 2.10 and 2.20, in the pre-blooming and blooming period samples. The results obtained by applying the Kjeldahl method are 2.16 and 2.25, respectively. The total protein content was calculated from the nitrogen content of the plant by using a nitrogen conversion factor of 6.25. The total free amino acid content in the pre-blooming and blooming period was found to 453.41 and 606.18 mg/100 g dried plant respectively.Conclusion: Since the total protein and free amino acid content of Artemisia abrotanum L. is higher during the blooming period, it should be preferred to be harvested during this period.Keywords: Artemisia abrotanum, Kjeldahl method, Dumas method, protein, free amino acid, LC-MS/MS, Ege University Office of Scientific Research Projects; [TDK-2019-250585], Acknowledgements: This study was supported by Ege University Office of Scientific Research Projects (TDK-2019-250585) .

Određivanje specifičnih sastojaka meda kao što su proteini svoju primjenu pronalazi u svrhu kontrole njihove kvalitete, te utvrđivanja autentičnosti. Tijekom ovog istraživanja primijenjena je metoda određivanja ukupnih proteina po Kjeldahl-u, indirektno preko dušika, s ciljem određivanja udjela proteina u uzorcima (n = 15) različitih vrsta meda (kadulja, suncokret, cvjetni, amorfa, uljana repica, mandarina, heljda, kesten, lipa, bagrem, zlatošipka). Rezultati su pokazali kako se udio ukupnih proteina kretao u rasponu od 0,13 % do 0,69 %, pri čemu je najviši udio određen u medu heljde, a najniži u medu bagrema. Dobiveni analitički podaci mogu predstavljati doprinos u procjeni kvalitete analiziranih proizvoda. Determination of specific ingredients of honey, such as proteins, finds its application in their quality control and determination of their authenticity. During this research, the Kjeldahl method was used in determination of total proteins, indirectly via nitrogen, with the aim of determination of the protein content in samples (n = 15) of different types of honey (sage, sunflower, floral, amorphous, rapeseed, mandarin, buckwheat, chestnut, linden, acacia, goldenrod). The results showed that the content of total proteins ranged from 0,13 % to 0,69 %, with the highest content determined in buckwheat honey and the lowest in acacia honey. The obtained analytical data can represent a contribution to the assessment of the quality of the analysed products.

Few studies have investigated the performance of anaerobic digestion (AD) to convert animal and agro-industrial wastes to organic fertilizers over a long-term field conditions. This paper studied three large-scale mesophilic digesters (D1–D3) over two years for their effects on feedstocks, which were dairy manure for D1 and D2 and co-digestion mixed manure and agro-industrial wastes for D3. Hydraulic retention times (HRT) were 9 d for D1, 12 d for D2, and 34 d for D3. Digester influent and effluent samples were taken every two months from the digesters and analyzed for pH, and concentrations of total solids (TS), ammonium nitrogen (NH4-N), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and eight metals. The study revealed high variability in converting feedstock in the three digesters. Compared with their respective influent, the mean digester effluent pH decreased from 7.9 by 0.6 in D1 (p < 0.01) and by 0.3 in D2 (p < 0.01), but it increased from 6.1 by 1.8 in D3 (p < 0.01). The mean digester effluent TS increased from 3.4% by 0.1% (p > 0.05) in D1, but it decreased from 4.9% by 1.3% in D2 (p < 0.05) and from 12.3% by 4.8% in D3 (p < 0.01). All three digesters significantly increased NH4-N concentrations by 21.4–81.8% (p < 0.05), but insignificantly changed TKN and TP concentrations (p > 0.05). Effects of AD on all metal concentrations were mixed and were insignificant (p > 0.05) because of large concentration variations. However, study of a ratio quotient (qMg) using magnesium (Mg) as the reference discovered accumulation of NH4-N, copper, potassium, and sodium, but loss of TKN, TP, iron, manganese, zinc, and calcium during AD for D2 and D3. The impact of AD conversion was closely related with types of feedstock (on pH) and HRT (on TS and NH4-N). The results of this study can assist in developing strategies for cleaner production using AD in an environmentally sustainable manner.

In sunflower, grain oil concentration (OG) determines oil industrial yield and protein concentration (PG) determines the protein of by-products as pellets and meals (PM). There are various methodologies to quantify total grain nitrogen concentration (NG): a) Kjeldahl (wet digestion); b) Dumas (dry combustion); c) NIRS (analysis of the spectrum of the light reflected by the sample). NIRS represents a promissory method for determining NG because it is simple and fast. The objective of this work was to compare the methods of NIRS, Kjeldahl and Dumas to quantify NG in sunflower grains and to adjust models to estimate PM from NG. Eighty-four samples of sunflower grains were selected covering a wide range of variation in NG (from 1.75 to 3.80 % taking Dumas reference) from a net of experiment conducted in southeastern Buenos Aires Province (2013-2014 and 2014-2015). NIRS was the most precise method for the determination of NG and presented a greater degree of agreement with Dumas regarding Kjeldahl. PM was satisfactorily estimated with NG. Therefore, NIRS could be a superior alternative to the other techniques because presents low cost, it is fast, no toxic and has the advantage of being able to determine other components of the grain simultaneously with the determination of NG. En girasol, la concentración de aceite (OG) determina el rendimiento industrial de los granos y la concentración de proteína (PG) determina la calidad de los subproductos como pellets y harinas (PM). Existen varias metodologías para cuantificar la concentración de nitrógeno total en grano (NG): a) Kjeldahl (digestión húmeda); b) Dumas (combustión seca); y c) NIRS (análisis del espectro de la luz reflejada por la muestra). NIRS representa un método promisorio para determinar NG porque es simple y rápido. El objetivo de este trabajo fue comparar los métodos de NIRS, Kjeldahl y Dumas para cuantificar NG en granos de girasol y ajustar modelos para estimar PM a partir de NG. Se seleccionaron ochenta y cuatro muestras de granos de girasol que cubren un amplio rango de NG (de 1.75 a 3.80% tomando la referencia del método de Dumas) de una red de experimentos realizados en el sudeste de la provincia de Buenos Aires (2013-2014 y 2014-2015). El NIRS fue el método más preciso para la determinación de NG y presentó un mayor grado de ajuste con Dumas respecto a Kjeldahl. La PM se estimó satisfactoriamente con NG. Por lo tanto, NIRS podría ser una alternativa superadora a las otras técnicas debido a su bajo costo, reducido tiempo. EEA Balcarce Fil: Diovisalvi, Natalia. Laboratorio de Suelos Fertilab; Argentina. Fil: Izquierdo, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Izquierdo, Natalia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Fil: Echeverría, Hernán Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Fil: Echeverría, Hernán Eduardo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Fil: García, Fernando. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Fil: Reussi Calvo, Nahuel. Laboratorio de Suelos Fertilab; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.

The total lipid and protein content of the invasive caprellid amphipod Caprella scaura, from the biofouling communities of fish farm cages in the Pagasitikos Gulf were analyzed and compared among seasons. Proteins were the most abundant component (48.5 – 49.3%). Lipid content was relatively lower, with a wider range (6.7 – 34%) and showed a distinct seasonal fluctuation with high values in the winter population and a gradual decrease in spring and summer, with the lowest values in Autumn. Composition of the fatty acids profile was consistent among the seasons, with palmitic (16:0), Oleic (18:1n-9), Eicosapentanoic (20:5n-3)(EPA) and Docosahexanoic acid (22:6n-3 )(DHA) being the most abundant fatty acids. The presence of high levels of EPA and DHA fatty acids makes the species a potential candidate for use of these organisms in aquaculture.

With the growing public interest in edible insects, breeders are forced to increase the volume of production and shorten the life cycle of farmed insects. The exact composition of the feed is the know-how of each manufacturer. The aim of this work was to determine the general impact of individual conventional types of feed (bran, whey, raw ware potatoes) on the life cycle rate of Tenebrio molitor (TM), larval mortality and the content of fats, fatty acids and nitrogenous substances in larvae and their excrements. For the reasons of sustainability of the state of nature and waste disposal, polystyrene foam was added to the experiment as feed. The experiment was performed in two phases—rearing for 21 weeks and 5 weeks. The nitrogen content was determined using the Kjeldahl method (ISO 1871: 2009), the fat content by the Soxhlet method and the fatty acid profile using a gas chromatograph with a flame ionization detector (FID). The results of the work show that the basis of the TM feed is wheat bran, not only due to the observed low larval mortality (45% over 21 weeks) and their optimal nutritional value (nitrogenous substances 53.6% DM, fat 37.1% DM, the highest total fatty acid content) but also due to the higher speed of TM development. Lower larval mortality during rearing was found when feeding dried whey and raw ware potatoes, but the development cycle rate was low. This confirmed that the bran as a feed allowed a fast life cycle with good larval nutritional parameters. From a nutritional and reproductive point of view, TM appeared to be a suitable alternative to animal production. Polystyrene as a feed, tested for biodegradation by TM larvae, caused the highest larval mortality (75% in 21 weeks). However, the content of nitrogenous substances in the larvae increased to 69.77%, in the excrement, it even increased to 82.68%, and there was no cannibalism among the larvae. The work thus demonstrated the possibility of biodegradation of polystyrene using TM larvae with an increase in nitrogenous substances in both larvae and excrement. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., RP/CPS/2020/006; FEKT-S-20-6215, IGA/FT/2021/008; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, TBU in Zlin [IGA/FT/2021/008]; project BUT in Brno [FEKT-S-20-6215]; Ministry of Education, Youth and Sports of the Czech Republic-DKRVO [RP/CPS/2020/006]

In order to identify the effects of varying cooking time on the quality of bone soup, the diversification of nutrient profiles and flavor compounds in bone soup prepared within 10 h' cooking was studied. The Kjeldahl method, inductively coupled plasma mass spectrometry (ICP-MS), automatic amino acid analyzer (AAA analyzer), high performance liquid chromatography (HPLC), solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) were applied to determine the changes o f crude protein, minerals, free amino acids (FAAs), 5′-nucleotides, and volatile compounds in the soup, respectively. During the 10 h cooking, the concentration of nutrients and flavor compounds reached their maximum and then decreased, except for minerals, which continued to increase in concentration. 18 FAAs were identified in all samples, which were related with I-collagen hydrolysis. Taste FAAs contributed little to the flavor of soup. Bitter amino acids increased significantly (P

1-phenyl(phenylimino)methyl)pyrrolidine-2,5-dione (FFMP) is a derivative of a well-studied class of organic compounds, pyrrolidine-2,5-diones, which have a wide spectrum of biological activity. Investigation in vivo in laboratory mice showed that FFMP, being an almost non-toxic compound (according to K. K. Sidorov), exhibits a pronounced analgesic activity, which is 1,6 times higher than the reference drug (metamizole sodium), acting in pain caused by chemical stimuli - algogens (model of visceral pain). This paper presents the results of attestation of the primary standard sample FFMP by the “mass balance” method. The structure of the compound was confirmed by X-ray structural analysis (XRD), mass spectrometry, nuclear magnetic resonance (NMR) spectrometry and infrared spectrometry (IR). The content of related organic impurities was determined by high performance liquid chromatography (HPLC). The content of volatile substances and inorganic impurities has been determined. The “mass balance” method was used to calculate the content of the main substance in the FFMP substance. The calculated value has been proven to be equivalent to the quantification value obtained by Kjeldahl titration. Using a certified primary standard sample, a method for the quantitative determination of the main substance by HPLC was developed and validated. Chromatographic separation was achieved in the acetonitrile / 0,15% (v/v) aqueous formic acid solution (pH 2,5) in a gradient mode on a Tosoh ODS column (4,6 × 250 mm, 5 μm) with a flow rate of 1,0 mL/min in 35 min. The signal was recorded using a multiwave UV detector at a wavelength of 257 nm.

Low rates of diatom positivity in the closed organs of drowning victims present challenges for diatom testing. High positivity rates in closed organs of non-drowning victims also raise an important issue. These contradictory findings were common in diatom testing studies undertaken during the 1960-80 s, but the reasons remained unclear. In the present study, we identified one of the most important factors associated with false-positive results in diatom testing using strong acid. One to 290 false-positive diatoms were found in reused Kjeldahl flasks that were thoroughly washed after the first diatom testing and kept free of tissue before the second testing. False-positive results occurred in 11 of 20 cases when more than approximately 10,000 diatoms were present in digested tissue or water samples. Reused flasks were found to contain many common diatoms (30 µm), including Cocconeis, Cymbella, Diatoma, Gomphonema, Navicula, and Nitzschia, in agreement with reports of diatoms identified in closed organs. Surprisingly, such false-positive results occurred even at the sixth diatom testing using the same flasks kept free of tissues in each analysis. In contrast, no diatoms were detected in any reagent or associated with other glassware. Thus, reuse of Kjeldahl flasks can readily cause false-positive results that cannot be completely prevented by cleaning the flasks using alkali detergents, as evidenced by detection of diatoms even after six tests. We assume that diatoms causing false-positive results are partially melted by heating and fixed onto the flask's inner surface glass, as the diatom frustule consists primarily of SiO

The objective of this study was to explore the changes in physicochemical properties and bacterial community during swine manure composting with a new compost tray (CT). The results showed that the organic matter (OM), moisture content (MC), and C/N decreased. The total Kjeldahl nitrogen (TKN), P2O5, K2O and humic acids (HAs) contents of the compost increased. The properties of the final compost product comply with the requirements of regulation except for the moisture according to NY/T 525-2012. Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes were the major phyla during the composting. Genus Terrisporobacter played a key role in degrading organic (OM). The content of K2O was main factors driving the succession of bacterial communities. These findings shed some novel lights into the dynamic changes of physicochemical propertied and their impact on bacterial community in a composting process.

In situ scanning electron microscopy/energy-dispersive spectroscopy (SEM-EDS) was used for depth profiling of black rice and the visualisation and quantification of the heterogeneous protein distribution. The SEM-EDS images of black rice grains revealed high protein content in the aleuronic layer, cell membrane and amyloplasts, especially in the spheroidal particles among the amyloplasts. This phenomenon has not been directly observed by other apparatuses because successive abrasion of brown rice by milling destroys the integrity of the cell walls and amyloplasts. Consistent with the SEM-EDS findings, confocal laser scanning microscopy and the Kjeldahl method preformed after successive milling indicated that the protein content of black rice decreases from the surface to the inner layer. Pasting curves obtained with a viscometer indicate that the protein distribution significantly affects the peak viscosity, setback viscosity, and pasting temperature of rice starch. Protein extraction weakened the structural stability of starch granules, possibly because the protective effect of protein is lost during extraction. This study improves the understanding of the protein distribution in rice grains and its effect on the pasting properties of rice starch; the findings are useful in food processing for managing rice nutrient compositions.

This study investigates the suitability of a sequencing batch reactor (SBR) for treating the liquor (HTCL) derived from hydrothermal carbonization (HTC) of sewage sludge in addition to the influent municipal wastewater. The SBR was fed for 80 days with an increasing mixing ratio HTCL/municipal wastewater. HTCL was used as external carbon source to enhance the denitrification process in the water line of the wastewater treatment plant (WWTP). The feeding of the HTCL caused an overloading in the COD and TKN concentration of the biological treatment equal to, respectively, 25% and 8% (Period II), 50% and 16% (Period III) and 100% and 32% (Period IV). Results revealed that good efficiencies of COD removal were obtained during the entire experimental test, accounting up to 91% in Period IV. Moreover, the removal of TN was improved increasing from 28% in the reference period (Period I), where no HTCL was fed, to 33%, 47% and 64% respectively in Period II, III and IV. Thus, an improvement in the denitrification process was obtained when HTCL was fed to the biological reactor in addition to the influent wastewater. The implementation of the SBR system was supported by nitrate uptake rate (NUR) tests and respirometric assays to evaluate the nitrate removal after the addition of HTCL and the fraction of readily biodegradable COD (RBCOD) and soluble biodegradable COD (sCODbio) on the total COD of the HTCL.

Seaweeds have been incorporated in the daily diet of several human cultures since ancient times, due to their nutritional characteristics and healthy properties. The brown seaweeds Undaria pinnatifida, Saccharina latissima, Sacchoriza polyschides, and Laminaria ochroleuca were collected in the Viana do Castelo (Portugal) bay to assess their proximate composition analysis. As a result, the algal biomass was dried, and its moisture and ash content were determined. The dried biomass was then analyzed for total nitrogen/total protein (using the Kjeldahl method), total fiber content (through fiber analyzer digestion), total lipids (in a Soxhlet apparatus), and fatty acid characterization (by gas chromatography-mass spectrometry). Apart from phosphorus, which was analyzed by spectrophotometry, the ashes were employed for mineral and trace element characterization via dry mineralization and quantified using flame atomic absorption spectrometry. Moreover, the total phenolic content was assessed spectrophotometrically by the Folin-Ciocalteu method in the algal aqueous extracts. Analyses showed that their protein concentrations ranged from 12 to 24% dry weight (DW), while lipid concentrations varied between 0.51% and 1.52% DW. Regarding the carbohydrate concentration in these seaweeds, a concentration between 48% and 60% DW was observed. The S. polyschides had the highest overall total phenolic content (6.19 × 10−3 g GAE/100 g of dried algae), while L. ochroleuca had the lowest amount (3.72 × 10−3 g GAE/100 g of dried algae). U. pinnatifida had the highest total fatty acid content (35.13 mg/g DW), whereas S. latissima presented the lowest value (22.59 mg/g DW). Significant concentrations of highly unsaturated fatty acids (HUFA) were observed in both seaweeds, with U. pinnatifida having the highest value (10.20 mg/g DW) and S. latissima the lowest content (4.81 mg/g DW). It is also highlighted that these seaweeds have a nutritional relevance as a source of essential nutrients, including nitrogen, potassium, sodium, calcium, magnesium, and iron.

Biochar is a carbon rich product obtained from pyrolysis of biomass. The use of biochar as soil amendment has been boosted in the last years due to its possible influence on fertility, including its potential ability to lower mineral nitrogen losses, but specially for its potential to reduce greenhouse gases and to increase carbon sequestration in soil. However, the studies on the effects of biochar on nitrogen forms in soil are heterogeneous and contradictory. The present work aims to clarify this point by applying 6 different biochars (with different origin and production process) on 6 different soils (of different properties). The amendment corresponded to an agronomic addition rate of 30 Mg ha−1, together with the addition of urea at a 100 kg N per ha rate. Then those mixtures were incubated for one year at a 60% of the WHC. The samples were analyzed for nitrogen forms (Kjeldahl-N, ammonium-N, nitrate-N, nitrite-N, and microbial-N) at different incubation times (1 week, 1 month, 4 months and 1 year after the addition). The results showed that the effects of different biochars on the soil nitrogen forms were variegated, mainly attributable to soil properties, and to a lesser extent to the particular biochar used. Overall, the Kjeldahl-N (KN) decreased after the incubation time, and only the mixtures with N-rich biochars achieved slightly higher KN compared to controls. Also, biochars tended to induce a decrease in NH4+-N, and, especially, in NO3–-N. The biochars causing highest shifts on N inorganic forms were those produced from agronomic sources (olive and corn wastes) and the one from pine wood materials subjected to high pyrolysis temperature conditions.

Compost leachate is a strong wastewater with high organics, TKN, and ammonia nitrogen and anaerobic processes like the ones carried out in an ABR are of interest. ABR is highly efficient in removing COD but the TKN removal performance in this reactor has been reported to be low, and only some part of organic nitrogen is converted to ammonia in it. Ammonia has inhibitory effects on the acetogenic bacteria and the biogas production efficiency. In this work, a pilot scale of ABR with 8 compartments was used, and its last four compartments were filled with zeolite. Based on the EDS analysis, the zeolite used was clinoptilolite with an ammonium adsorption capacity equal to 1.02 meq/g. The bioreactor was operated at HRTs of 3, 4, and 5 days, the filling ratios of 10%, 20%, and 30%, and the initial COD concentrations of 10 000, 20 000, and 30 000 mg/L. The results showed that the maximum removal efficiency of TKN and organic nitrogen was, respectively, equal to 48% and 100%. Increasing the filling ratio in the reactor increased the removal efficiency of TKN and organic nitrogen but increasing OLR reduced the removal efficiency of the reactor. The initial TKN/ammonia ratio was 0.45, which was increased by elevating the filling ratio in the reactor, and in 30%, it reached 0.91. The results obtained also showed that zeolite had a great effect on the ABR performance; therefore, it could be used to treat a highly strong wastewater to suppress the anaerobic biological growth inhibitors like ammonia.

High Rate Algal Ponds (HRAP) are a sustainable alternative for wastewater treatment. However, HRAPs must be shallow (h = 0.2–0.3 m) for adequate sunlight penetration and require relatively long hydraulic retention times (HRT, >5 d) for effective pollutant removal, which results in high area footprints. In this context, a deep HRAP (h = 1.2 m) was equipped with red light-emitting diodes (LED, 660 nm) to provide photosynthetic active radiation in the aphotic zone. A conventional HRAP (HRAP1) and the LED-enhanced HRAP (HRAP2) were operated with identical working volumes (1.25 m3) and HRT (10 d), treating digestate dilutions of 5% (Stages S-0, S-I), 25% (S-II, S-III) and 50% (v/v) (S-IV to S-VI). The HRAP2 used only 25% of the area needed by the HRAP1 but LEDs used 1.4 (S-0 to S-II), 2.3 (S-III, S-IV) and 3.4 (S-V) times the energy consumed in HRAP1. HRAP2 presented similar performance to HRAP1 during the treatment of 5% and 25%-digestate, achieving removals above 75% for TSS, COD, TAN, and TKN. However, HRAP1 showed better treatment performance at 50%-digestate, likely due to more intense light radiation induced by its shallow depth, resulting in higher microalgal activity. Biomass productivity decreased with increasing digestate concentration, showing averages in HRAP1 and HRAP2 of 9 and 3 gVSS·m−2d−1, respectively, during feeding with 5%-digestate. With 25%, average productivities ranged from 2 to 5 and 2 to 6 gVSS·m−2d−1, and from 0 to 6 and 0 to 4 gVSS·m−2d−1 with 50%-digestate, respectively. Both systems showed reasonable nitrogen and phosphorus recoveries in the biomass (TN: 8–17% and 6–34%; TP: 10–45% and 5–48% for HRAP1 and HRAP2, respectively). Nitrogen volatilization, likely as NH3, N2O, and N2, was caused by stripping and nitrification-denitrification in both systems. Our data suggest that using LED-lighting to complement sunlight in deeper HRAPs is a promising alternative for enhancing microalgae-based reactors for digestate treatment.

In this study the correlations between protein contents of different kinds of natural rubber were considered with rheological behavior, compression set and hardness of rubber compounds based on natural rubber. At the first stage, protein contents were obtained by Kjeldahl method and correlated with normalized absorbance of amine band in NR's attenuated total reflection Fourier transform infrared spectra and shown linear behavior. At the second stage, correlations between the protein contents obtained by the spectra were considered with rheological behavior, compression set and hardness of rubber compounds and shown second order fitting models. The introduced models were applied to predict these features in case studies. Results were shown that Mooney viscosity, torque difference, optimum cure time, scorch time, cure rate index and hardness can be predicted by lower than 10% while compression set can be estimated by lower than 20% error. This significant attitude is a nondestructive and fast technique that uses little quantity of NR for prediction of some NR based compounds properties, before compounding.