Ispitivanje koagulacione aktivnosti prirodnih koagulanata ekstrahovanih iz različitih sorti pasulja

Coagulation and flocculation by adding chemicals are the methods that are usually used for removal of water turbidity. This study is concerned with the coagulation activity of extracts of various strains of bean. The aim was to ascertain if bean varieties influence coagulation activity. Active components were extracted from 1 g of ground sample with 100 ml distilled water. Contents of dry matter and nitrogen were specified in the solid samples, and the content of soluble nitrogen was determined in the extracts. These data were used to calculate the efficiency of extraction of nitrogen-containing compounds. The coagulation activity was assessed by jar test using synthetic turbid water, of the initial pH 9 and turbidity 35 NTU. The jar test was carried out by adding different amounts of extracts to model water, and stirring the content. After sedimentation for 1 h, residual turbidity was determined by turbidimeter and coagulation activity was calculated. The increment of organic matter concentration after the coagulation was also determined. These experiments confirmed that extracts of all investigated strains of bean could be used successfully as natural coagulants.Koagulacija i flokulacija predstavljaju najčešće primenjivane metode za bistrenje vode, i uglavnom se izvode dodatkom hemijskih koagulanata. U ovom radu je ispitivana koagulaciona aktivnost ekstrakata dobijenih iz semena različitih sorti pasulja, a s ciljem da se utvrdi mogućnost njihove primene kao prirodnih koagulanata za uklanjanje mutnoće vode, i da se utvrdi uticaj sorte pasulja na koagulacionu aktivnost. Ekstrakcija aktivnih komponenti je izvedena sa 100 ml destilovane vode iz 1 g samlevenog uzorka. U čvrstim uzorcima je određen sadržaj suve materije i azota, a u ekstraktima sadržaj rastvorljivog azota, na osnovu čega je određena efikasnost ekstrakcije jedinjenja sa azotom. Za određivanje koagulacione aktivnosti ekstrakata izveden je džar-test, dodavanjem različitih doza ekstrakata model vodi, čiji je pH 9 i početna mutnoća 35 NTU. Nakon mešanja u određenom vremenskom intervalu, čaše su ostavljene da se njihov sadržaj istaloži, a zatim je u bistrom delu određivana mutnoća, i preko nje koagulaciona aktivnost. Takođe je utvrđen doprinos svakog od ekstrakata porastu sadržaja organskih materija u vodi nakon njenog bistrenja u odnosu na slepu probu, a preko permanganatnog broja. Ovim eksperimentima potvrđeno je da se ekstrakti svih ispitivanih sorti pasulja mogu uspešno primeniti kao prirodni koagulanti

Changes in techno-functional properties of maize flours induced by dry-heat treatment

of the flours by reducing the enzyme activity and moisture content. Besides the biological effects, the dry-heat process has a significant impact on the techno-functional and nutritional properties of flours. Hence, the effects of the dry heat treatment at different temperatures: 100, 125, 135, 150, and 165°C, on the technological and functional properties, as well as antioxidant capacity of maize flours were investigated. The experimental material consisted of two maize hybrids with different colors and kernel types (white-standard and blue-popping). Maize samples were ground on a lab mill to a fine powder (<500μm) and flour samples evenly spread on a glass plate and thermally treated for 1 h in a ventilation oven Memmert UF55. Results showed that dry heat treatment increased the insoluble dietary fibre and free phenolic compounds of the investigated maize flours, while the bound phenolic compounds, anthocyanins, and pasting properties decreased with the rising of the applied temperature. The antioxidant capacity ranged from 10.05 to 13.32 mmol Trolox Eq/kg and 20.51 to 24.03 mmol Trolox Eq/kg in white and blue maize flour, respectively. The water absorption index showed an increase to a temperature of 135°C after which it began to decrease and reached a minimum at a temperature of 165°C. Meanwhile, the solubility index increased with an increase of temperature, and doubled its value after a temperature of 135°C. The dry-heat treatments largely modulated pasting properties of maize flours. The untreated maize flour samples showed a higher peak viscosity than the treated samples. Especially, white and blue maize flour samples at 165oC reached the lowest viscosity value of all samples and the result was attributed to the structural changes in flour. Dry-heat treatment had a significant effect on the maize flour color parameters and the results of the parameters L*, a* and b* indicated that the flour showed darkening and browning effect as the dry heat treatment temperature increased. Browning also indicates the formation of melanoidins as the end-product of the Maillard reaction, which confirms the maximum value of antioxidant capacity at a temperature of 165°C. All results showed that a temperature of 135°C had favorable impact on the techno-functionality of maize flours. However, due to the different kernel structures of the used maize genotypes and inter-relations between chemical compounds within the food matrix, the overall impact of dry-heat treatments was not completely elucidated

Uticaj termičkih tretmana prerade na sadržaj masnih kiselina sojinog zrna i aktivnost lipoksigenaze

Effects of increased temperatures on the lipoxygenase activity and changes of soya bean fatty acids were observed in the present study. The kernels of soya bean cultivars Bosa and ZPS 015 were subjected to the treatments of extrusion, autoclaving, micronisation and microwave roasting. Depending on the technological processing procedure, the kernels were exposed to temperatures ranging from 60 to 150°C for 25 to 30 seconds during extrusion and for 30 minutes during autoclaving. The temperature that developed in the course of the microwave radiation and autoclaving did not cause statistically significant differences between oil content in heat treated and fresh kernels of soya bean. However, the oil content was higher in soya bean flakes (micronized kernels) and lower in grits than in fresh kernels. The heat treatments resulted in the significant decrease of the linolenic fatty acid content. Depending on the temperature and applied heat treatments, the content of linoleic and oleic fatty acid oscillated. High temperatures caused changes in unsaturated fatty acids with 18 carbon atoms resulting in relative increase of the stearic acid content. The lipoxygenase activity decreased in correlation with increased temperatures and the time of heating. The maximum drop of the activity was observed after kernel exposure to the extrusion and micronisation processes at the temperature of 100oC. However, a significant lipoxygenase activity increase was recorded in both studied cultivars after one-minute microwave heating, i.e. at the temperature about 60°C. A further temperature increase led to a gradual denaturation of the enzyme and therefore to its decreased activity.U ovom radu prikazani su rezultati promene aktivnosti lipoksigenaze 1 i sadržaja masnih kiselina u sojinom zrnu pod uticajem povišene temperature. Zrno soje sorte Bosa i ZPS 015 bilo je podvrgnuto tretmanima suve i vlažne ekstruzije, autoklaviranju, mikronizaciji i prženju u mikrotalasnoj peći. U zavisnosti od tehnološkog tretmana prerade zrno je bilo izloženo dejstvu povišene temperature od 60 do 150°C u trajanju od svega 25 do 30 sekundi pri ekstruziji do 30 minuta pri autoklaviranju. Povišena temperatura tokom mikrotalasnog prženja i autoklaviranja nije uticala na sadržaj ulja u sojinom zrnu. Međutim, u sojinim flekicama sadržaj ulja bio je viši, a u grizu niži od sadržaja u sirovom sojinom zrnu. Primenjeni termički tretmani prerade uticali su na značajno smanjenje sadržaja linolenske kiseline u ulju sojinog zrna. U zavisnosti od temperature, kao i vrste termičkog tretmana sadržaj linolne i oleinske kiseline u prerađenom sojinom zrnu je varirao. Povišena temperatura uslovila je promene nezasićenih masnih kiselina sa 18 ugljenikovih atoma rezultirajući povećanje sadržaja stearinske kiseline. Prema našim rezultatima aktivnost lipoksiganaze je opadala sa povećanjem temperature i produženjem tretmana prerade. Maksimalan pad aktivnosti lipoksigenaze utvrđen je već nakon izlaganja zrna temperaturi od 100oC tokom ekstruzije i mikronizacije. Međutim, nakom jednog minuta prženja zrna u mikrotalasnoj peći (60°C) aktivnost lipoksigenaze je bila viša u odnosu na aktivnost u sirovom zrnu. Daljim produženjem tretmana, a time i povećanjem temperature došlo je do postepene denaturacije enzima i smanjenja aktivnosti

Novel trends in application and pretreatment of lignocellulosic agricultural waste

Lignocellulosic biomass represents the most abundant renewable material in the world, whereas agricultural residues, including those from maize cultivation, comprise a significant fraction of the total plant waste that can be repurposed for various applications. Lignocellulosic feedstocks are non-edible and consist mainly of: cellulose, hemicellulose, and lignin, along with extractive compounds. Pretreatment is required to separate the lignocellulosic biomass into its constituents for efficient utilization. Even after extensive research and development of numerous techniques, pretreatment remains one of the most expensive phases in converting lignocellulosic biomass into biobased products

Oat varieties with different hull colours as potential sources of phytochemicals for the food and feed industry

Whole grain cereals are considered essential components of nutrition because of their healthpromoting properties. Oats (Avena sativa L.) are naturally gluten-free cereals suitable for persons suffering from celiac disease, abundant in dietary fibre, among which particularly β- glucans offer medical advantages like lowering cholesterol levels, reducing glucose uptake, and decreasing plasma insulin levels [1,2]. Nevertheless, oats are abundant in phenolic acids, flavonoids, carotenoids, vitamin E, and phytosterols [3,4]. This study aimed to investigate the antioxidant properties of the dehulled grain and hulls of three oat genotypes with different hull colours: yellow, brown and black. The contents of total phenolic compounds, phenolic acids, β-glucan, and antioxidant capacity of the oat grains and oat hulls were analysed. Significant differences were noticed among the tested samples, especially between parameter values determined in hulls, compared to those in grain. Oat hulls had higher contents of total phenolic compounds (11320.11-24352.48 μg GAE/g d.m.) compared to grain (841.89-982.08 μg GAE/g d.m.); as well as the detected phenolic acids, namely: p-coumaric, ferulic, isoferulic, vanillic and syringic acid. Ferulic acid was predominant, in both the grain (395.88- 589.14 μg/g d.m.) and hulls (4987.02-13794.82 μg/g d.m.). The antioxidant capacity was higher in oat hulls, also, ranging from 42.31 mmol Trolox/kg d.m., in yellow hulls to 53.16 mmol Trolox/kg d.m. in brown hulls, and from 22.61 mmol Trolox/kg d.m. in black grain, to 25.06 mmol Trolox/kg d.m. in brown grain. Conversely, the β-glucan content determined in the grain samples was significantly higher, ranging from 4.07% to 5.33% in grain, and only 0.03-0.06% in hulls. The anthocyanins and proanthocyanidins were not detected, which indicates that the colour of the oat varieties did not originate from these pigmented bioactive compounds. The investigated oat genotypes exhibit notable potential for use by the food and feed industries as sources of phytochemicals with potential health-promoting benefits

Optimizacija procesa ekstrakcije antocijana iz semenjače crne soje za pripremu funkcionalne hrane od kukuruza

Black soybean seed coat has a considerable content of anthocyanins which can providea positive effect on the health of the consumers through food products enriched with the extracts of these valuable bioactive compounds. Nevertheless, the use of soybean seed coat, a by-product from soybean processing, additionally valorizes this raw material.The possibility of enrichment of sweet maize grains with anthocyanin extract was investigated. Several procedures with acetic acid were applied in the experiments of anthocyanins extraction from black soybean seed coat. During the marination process, the grains were stained, changing their standard yellow color to a crimson red. Since the brines with the addition of citric acid became cloudy (opalescent) after some time, lactic acid was used as an anthocyanin stabilizer in the continuation of the research. Depending on the extraction conditions, the spectrophotometrically determined content of total anthocyanins in the solution varied from 3541.90 to 5387.70 μg CGE/g d.m., and in the marinated maize grain between 179.89 and 286.05 μg CGE/g d.m. After seven days, the total anthocyanin content in the grain did not increase significantly, so this aging period was selected as optimal for marinating maize products.Semenjača crne soje ima značajan sadržaj antocijana, koji mogu pozitivno uticati na zdravlje potrošača kroz prehrambene proizvode obogaćene ekstraktima ovih vrednih bioaktivnih jedinjenja. Istovremeno, upotrebom sojine semenjače, sporednog proizvoda prerade soje, dodatno se valorizuje ova sirovinu. Ispitivana je mogućnost obogaćivanja zrna kukuruza šećerca ekstraktom antocijana. U eksperimentima ekstrakcije antocijana iz semenjače crne soje primenjeno je nekoliko postupaka sa sirćetnom kiselinom. Tokom procesa mariniranja, zrna su promenila boju, menjajući standardnu žutu boju u tamnocrvenu. S obzirom da su posle izvesnog vremena nalivi za mariniranje sa dodatkom limunske kiseline postali zamućeni (opalescentni), u nastavku istraživanja je korišćena mlečna kiselina kao stabilizator antocijana. U zavisnosti od uslova ekstrakcije, spektrofotometrijski utvrđen sadržaj ukupnih antocijana u rastvoru varirao je od 3541,90 do 5387,70 mg CGE/g d.m., a u zrnu mariniranog kukuruza između 179,89 i 286,05 mg CGE/g. Posle sedam dana, ukupan sadržaj antocijana u zrnu nije značajno povećan, pa je ovaj period odležavanja izabran kao optimalan za mariniranje proizvoda od kukuruza

Possibilities of maize hybrids utilization in canned baby corn production

Five maize hybrids were used in this research: two yellow and one white dent, sweet hybrid, and yellow popcorn. Five brine recipes with acetic acid were examined, of which two with the addition of potassium sorbate. The brines with preservatives were stable for 16 months without colour changes of the liquid and corn cobs. The pH of brines ranged from 3.39 to 3.89. Canned hybrids ZP 366 and ZP 611k in brine without sugar, and with the addition of potassium sorbate and potassium metabisulfite marked as Number 5, showed the best sensory characteristics. The protein content determined in ZP 366 (9.56 %) and ZP 611k (10.23 %) did not vary significantly compared to whole-grain maize flour, while crude fibre content (7.67 and 6.88 %), and ash content (21.96 and 20.72 %) were significantly higher than in flour (crude fibre: 2.40; 2.64 %, ash:1.35; 1.48 %, respectively). This research will be continued in order to implement preliminary findings and new data on this subjec

Zrno žitarica sa niskim potencijalom za formiranje akrilamida kao sirovina za bezbednije prehrambene proizvode na bazi žitarica u Srbiji

The presence of acrylamide, a mutagen and a Group 2A carcinogen, in food, is a health concern that might raise cancer risk. Acrylamide is mainly formed in the Maillard reaction between free asparagine and reducing sugars, during industrial thermal food processing or home cooking, at a temperature over 120°C. The European Commission Regulation (EU) 2017/2158 established mitigation measures and benchmarks for acrylamide levels in some food categories, which were incorporated into the Serbian regulation. Research shows that cereal-based products may bring about 20-60% of acrylamide intake. In Serbia, there are no guidelines for the cultivation of cereals with a reduced potential for acrylamide formation. Knowing that the amount of free asparagine is proportional to the formation of acrylamide in the majority of food products, one of the key approaches is to select the ingredients with a lower level of asparagine. Studies indicate that applying foliar fertilizers with increased sulfur content in some cereals influences the decrease of free asparagine synthesis in grain, lowering the acrylamide potential in cerealbased foods. Furthermore, the choice of the appropriate raw material and production parameters can significantly influence the formation of acrylamide in food products. This review aims to provide insight into current strategies for the mitigation of acrylamide in cereal-based foods, as the status of acrylamide in Serbian regulationsPrisustvo akrilamida, mutagena i kancerogena grupe 2A, u hrani, predstavlja zdravstveni problem koji može povećati rizik od raka. Akrilamid se uglavnom formira u Majarovoj reakciji između slobodnog asparagina i redukujuc'ih šec'era, tokom industrijske termičke obrade hrane ili kuvanja kod kuće, na temperaturi iznad 120°C. Uredbom Evropske komisije (EU) 2017/2158 su utvrđene mere ublažavanja i granične vrednosti za sadržaj akrilamida u nekim kategorijama hrane, koje su uvršćene u srpsku regulativu. Istraživanja pokazuju da proizvodi na bazi žitarica mogu dovesti do 20-60% unosa akrilamida. U Srbiji ne postoje smernice za gajenje žitarica sa smanjenim potencijalom za stvaranje akrilamida. S' obzirom na to da je količina slobodnog asparagina proporcionalna formiranju akrilamida u većini prehrambenih proizvoda, jedan od ključnih pristupa predstavlja odabir sastojaka nižeg sadržaja asparagina. Istraživanja pokazuju da kod nekih žitarica, primena folijarnog đubriva sa povec'anim sadržajem sumpora utiče na smanjenje sinteze slobodnog asparagina u zrnu, smanjujuc'i potencijal akrilamida u namirnicama na bazi žitarica. Takođe, izbor odgovarajuće sirovine i proizvodnih parametara može značajno uticati na formiranje akrilamida u prehrambenim proizvodima.Ovaj pregledni rad ima za cilj da pruži uvid u aktuelne strategije za snižavanje akrilamida u namirnicama na bazi žitarica i status akrilamida u srpskim propisima

Nutritional composition and bioactive properties of the wholegrain flour obtained from maize inbred lines

The aim of this study was to assess the chemical composition and bioactive properties of the wholegrain flour obtained from eleven maize inbred lines to identify genotypes with increased potential for the development of hybrids with high nutritional and functional value, suitable for food production. The maize inbreds, including seven standard yellow, two QPM (quality protein maize) and two lines for red kernel hybrids, were grown in the experimental field of the Maize Research Institute at the location of Zemun Polje, Serbia. Wholegrain maize flour was got by grinding the maize grain in a laboratory mill. The assessment of the chemical composition and content of certain bioactive compounds, as well as the total antioxidant capacity, was conducted using standard laboratory procedures. The highest starch content (73.73%) was determined in line L8, while line L10 had the highest protein content (12.82%). Among soluble proteins, the α-zein fraction was dominant in most of the lines, ranging from 0.92% to 3.57%. The highest content of total fibres (NDF) was determined in red kernel line L9 (15.77%). Line L8 was the richest in total carotenoids (21.08 μg βCE/g d.m.), while line L7 had the highest total antioxidant capacity (34.30 mmol Trolox/kg d.m.), which can be explained by the presence of anthocyanins in the red grain. Line L1 had the highest content of total sugars (3.36%), and line L4 had the lowest (1.44%). Most of the samples of inbred lines investigated in this study showed good quality parameters regarding chemical composition and bioactive properties. The obtained results may provide some valuable guidelines needed in the following stages of maize breeding and open up various possibilities for the utilization of wholegrain maize flour in the food industry.Cilj ovog istraživanja bio je da se odrede hemijski sastav i bioaktivna svojstva integralnog brašna dobijenog od jedanaest inbred linija kukuruza u cilju identifikacije genotipova sa povećanim potencijalom za razvoj hibrida visoke nutritivne i funkcionalne vrednosti, pogodnih za proizvodnju hrane. Linije kukuruza, uključujući sedam standardnih žutih, dve QPM i dve linije za hibrid crvenog zrna, gajene su na oglednom polju Instituta za kukuruz na lokaciji Zemun Polje, Srbija. Integralno kukuruzno brašno dobijeno je mlevenjem u laboratorijskom mlinu. Procena hemijskog sastava i sadržaja pojedinih bioaktivnih jedinjenja, kao i ukupnog antioksidativnog kapaciteta, sprovedena je primenom standardnih laboratorijskih procedura. Najviši sadržaj skroba (73,73%) utvrđen je u liniji L8, dok je linija L10 imala najveći sadržaj proteina (12,82%). Među rastvorljivim proteinima, frakcija α-zeina bila je dominantna u većini linija, u rasponu od 0,92% do 3,57%. Najveći sadržaj ukupnih vlakana (NDF) utvrđen je u zrnu crvene boje Linije 9 (15,77%). Linija L8 je bila najbogatija ukupnim karotenoidima (21,08 mg βCE/g s.m.), dok je linija L7 imala najveći ukupni antioksidativni kapacitet (34,30 mmol Trolox/kg d.m.), što se može objasniti prisustvom antocijana u crvenom zrnu. Linija L1 je imala najveći sadržaj ukupnih šećera (3,36%), a linija L4 imala je najmanji (1,44%). Svi uzorci novih inbred linija ispitivani u ovoj studiji pokazali su dobre parametre kvaliteta u pogledu hemijskog sastava i bioaktivnih svojstava. Dobijeni rezultati mogu dati neke dragocene smernice potrebne u narednim fazama oplemenjivanja kukuruza, kao i otvoriti različite mogućnosti za korišćenje integralnog kukuruznog brašna u prehrambenoj industriji