Ispitivanje kinetike sušenja krompira u laboratorijskim uslovima

Chemistry is in its nature a fundamental science, but nowadays its results are increasingly used in practice. In such a way, many syntheses of important nutrition and industrial compounds (chemical technology), or destruction of harmful substances (chemical ecology) have been developed. The analytic part of chemistry (analytical chemistry) has found a significant usage even in optimization of technological processes of food technology. One of the oldest ways of food preservation is drying (dehydration). The basis of this process of preservation is to vaporize water, to dry enough the product, in order to stop the activity of enzymes and possibility of microorganisms’ development. Water in agricultural products is not free but bound to dry matter. Therefore, for its vaporizing it is necessary to bring enough heat. The part of the brought heat is used for vaporizing water, but one part of it becomes the energy for activation of several chemical reactions that decrease the nutritive values and the quality of future food. Therefore, the important engineering problem emerges: determination of optimal conditions for drying. For optimization of technological process of drying, it is necessary to do mathematical modeling of dependence of water vaporizing speed from environmental conditions beforehand. The aim of this paper is to determine potato pieces drying kinetics in laboratory dryer, in order to determine the optimal conditions for its industrial dehydration. It was established that in the first quarter of the time of drying evaporated 28.3% of total evaporation of water, and then in order by quarters: 53%, 14.1% and 4.6%, respectively. The greatest speed of drying was realized at moisture of potatoes about 50%.Hemija jeste, po svojoj prirodi, fundamentalna nauka, ali su danas njena saznanja sve više primenjena u praksi. Tako su razvijene mnoge sinteze važnih prehrambenih i industrijskih jedinjenja (hemijska tehnologija), ili razgradnja štetnih supstanci (hemijska ekologija). Analitički deo hemije (analitička hemija) našla je značajnu primenu čak i u optimizaciji tehnoloških postupaka tehnologije hrane. Jedan od najstarijih načina konzervisanja namirnica je sušenje (dehidracija). Osnova ovog postupka konzervisanja je da se voda ispari, da se proizvod dovoljno isuši, kako bi se sprečila aktivnost enzima i mogućnost razvoja mikroorganizama. Voda u poljoprivrednim proizvodima nije slobodna već je vezana za suvu materiju. Zato je za njeno isparavanje potrebno dovesti dovoljno toplote. Deo dovedene toplote se koristi za isparavanje vode, ali jedan njen deo postaje energija aktivacije za niz hemijskih reakcija koje umanjuju nutritivnu vrednost i kvalitet buduće hrane. Stoga se postavlja važan inženjerski problem: odrediti optimalne uslove sušenja. Za optimizaciju tehnološkog postupka sušenja neophodno je prethodno izvršiti matematičko modeliranje zavisnosti brzine isparavanja vode od uslova sredine. Cilj ovog rada je da utvrdi kinetiku sušenja komada krompira u laboratorijskoj sušari, kako bi se zatim utvrdili optimalni uslovi za njegovu industrijsku dehidraciju. Utvrđeno je da u prvoj četvrtini vremena sušenja ispari 28,3% ukupno isparene vode, a zatim redom po četvrtinama: 53%, 14,1% i 4,6%. Najveća brzina sušenja ostvarena je pri vlažnosti krompira od oko 50%

Kinetika sušenja i kvalitet jabuke sorti Granny Smith, Idared i Jonagold

Apple is nutritionally valuable and present as fresh fruit in human nutrition throughout the year. Also apple is a raw material in food processing, primarily in the production of juices, nectars, refreshing soft drinks, marmalades, jams, compotes, apple cider vinegar and dried fruits. In the last decade on the world market there is a great interest in dried apple products (commercially called apple chips). During preservation by drying the technological process aimed at the final product of optimal quality is required. The subject of this paper is the kinetics of the apple cv. Granny Smith, cv. Idared and cv. Jonagold drying in laboratory dehydrator for the purpose of pinpointing at which level of humidity the maximum speed of evaporation is achieved and at which level of humidity apple slices begin to change in colour and geometric shape. Parameters of the drying process were the same for all three cultivars, 3hrs at air temperature of 70oC and 5hrs at air temperature of 50o. The amount of evaporated water is expressed in relative and absolute units of measure. The purpose of this paper is to determine which one of the three tested cultivars provides the best properties for drying, i.e. in terms of oxidation of polyphenolic compounds to find the cultivar which will provide that the final product is technologically and organoleptically the most acceptable. The results showed that the sample cv. Granny Smith expressed the least oxidation of polyphenolic compounds (browning), curved edges and shrivelled apple slices. After that the sample cv. Jonagold followed. The sample cv. Idared showed the worst results. Following the drying kinetics of all three samples, it can be concluded that the cultivars Granny Smith and Jonagold were achieving the lower maximum speed of evaporation, unlike the cultivar Idared. The cultivars Granny Smith and Jonagold have attained consistent drying and in this way the technological process was finished with a smaller temperature stress for plant tissue, resulting in a much better quality of the final product.Nutritivno vredni plodovi jabuke se koriste kao stono voće tokom cele godine, ali i kao sirovina u prehrambenoj industriji za proizvodnju sokova, nektara, osvežavajućih bezalkoholnih pića, marmelada, džemova, kompota, jabukovog sirćeta i sušenih plodova. Poslednjih decenija na svetskom tržištu postoji veliko interesovanje za sušene proizvode od jabuke (marketinški nazvane čips od jabuke). Pri konzervisanju sušenjem od tehnološkog postupka se zahteva da obezbedi gotov proizvod optimalnog kvaliteta. U radu je izučavana kinetika sušenja jabuke sorti Granny Smith, Idared i Jonagold u laboratorijskom dehidratoru sa ciljem da se uoči pri kojim sadržajima vlage dolazi do postizanja maksimalne brzine isparavanja i pri kojoj vlažnosti kolutovi jabuke počinju da menjaju boju i geometrijski oblik. Parametri procesa sušenja su isti za sve tri sorte, 3 h na temperaturi vazduha od 70oC i 5 h na temperaturi vazduha od 50oC. Količina isparene vode je izražena u relativnim i apsolutnim jedinicama mere. Cilj rada je da se utvrdi koja od ispitivane tri sorte pruža najbolje mogućnosti za sušenje, tj. da se sa aspekta oksidacije polifenolnih jedinjenja pronađe sorta koja omogućava da gotov proizvod bude tehnološki i organoleptički najprihvatljiviji. Rezultati su pokazali da je uzorak sorte Granny Smith pored najmanje izražene oksidacije polifenolnih jedinjenja (tamnjenje) imao i najmanje izraženo povijanje ivica i smežuravanje kolutova, potom sledi sorta Jonagold, a najlošije rezultate je pokazao uzorak sorte Idared. Prateći kinetiku sušenja sva tri uzorka zaključuje se da su sorte Granny Smith i Jonagold postigle manje maksimalne brzine isparavanja, za razliku od sorte Idared. Sorte Granny Smith i Jonagold su imale ravnomerno sušenje i na taj način tehnološki postupak se vršio sa manjim temperaturnim stresom za biljno tkivo što je rezultiralo mnogo boljim kvalitetom gotovog proizvoda

Primena ultrafiltracije za bistrenje soka jabuke

Raw depectinized apple juice was clarified in a laboratory scale ultrafiltration (UF) system using ceramic tubular membranes (Tech-Sep Carbosep) with a molecular weight cut-off of 300,000, 50,000, and 30,000 daltons. The experiments have been carried out over a wide range of transmembrane pressures (100-400 kPa), temperatures (293-328 K), and feed flow rates (100-900 mL/min). Permeate flux significantly decreased with time until a steady state was established. The steady-state permeate flux reached a maximum at a transmembrane pressure of about 200 kPa. Higher permeate flux was obtained at higher temperatures due to lower permeate viscosity. A linear relationship between steady-state permeate flux and feed flow rate in logarithmic coordinates was obtained and the slope of these lines ranged from 0.22 to 0.31.Bistrenje depektinizovanog matičnog soka jabuke uspešno je vršeno ultrafiltracijom kroz keramičke cevne membrane proizvedene od cirkonijum-oksida i titan-dioksida na podlozi od poroznog ugljenika. Eksperimenti su vršeni uz potpunu recirkulaciju retentata i sa protocima napojne struje u modulu od 100-900 ml/min. Fluks permeata u početku opada sa vremenom, ali se posle određenog vremena uspostavlja stacionarno stanje. Stacionami fluks permeata, L dostiže maksimum pri transmembranskom pritisku od oko 200 kPa, nakon čega opada sa daljim porastom pritiska. To se može objasniti deformacijom čestica mutnoće u sloju gela, raskidanjem krupnijih lančastih agregata otvorene strukture i formiranjem sitnijih čestica koje se gušće pakuju u sloju gela, što dovodi do smanjenja poroznosti i propustljivosti sloja. U log-log koordinatnom sistemu stacionami fluks permeata linearno raste sa porastom protoka napojnog soka, pri čemu nagib ovih pravih varira od 0,22 do 0,31

Sinalbin degradation products in mild yellow mustard paste

Sinalbin degradation products in mild yellow mustard paste were investigated. The analyzed material consisted of a mild yellow mustard paste condiment and ground white mustard seeds which were originally used in the mustard paste production process. The samples were extracted in a Soxhlet extraction system and analyzed by gas chromatography - mass spectrometry (GC-MS) technique. The only sinalbin degradation product in ground mustard seeds was 2-(4-hydroxyphenyl)acetonitrile. The most abundant sinalbin degradation product in yellow mustard paste was 4-(hydroxymethyl)phenol. Other compounds identified in this sample were: 4-methyl phenol, 4-ethyl phenol, 4-(2-hydroxyethyl)phenol and 2-(4-hydroxyphenyl) ethanoic acid

Kinetika sušenja malina u laboratorijskim uslovima

For a long time Serbia has been an important producer, processor and exporter of the raspberry. From the point of view of primary production, we could be proud of our success. However, on the question of processing, we are somehow behind. The reason is the typical "line of least resistance". We have always earned enough by exporting frozen raspberry and no one has even tried to explore new products or other attractive useful values of this fruit. Namely, although the raspberry has attractive useful values (which brings high demand), it is known that it has some inviolable chemical engineering characteristics. The raspberry, due to its consistency, is very susceptible to mechanical damage. It is also known for its high breathing warmth, and therefore it can only be preserved for a short time. These characteristics impose upon the producers the necessity to quickly proceed with the conservation and processing. The best way to achieve the turnover of capital is by not processing it completely. When the raspberry is half-processed, investments are smaller and so are risks for the deterioration of the quality of the product. Among products not completely processed, made from raspberries and other types of fruits, the most convenient are certainly frozen or dried fruits. Unfortunately, up to now, little has been done on the drying process of the raspberry because the fruit is very perishable as a raw material and also various problems occur during the drying process. Positive results have, however, been achieved locally in the process of drying by freezing, i.e. lyophilizing. The subject of this paper is the kinetics of drying raspberry in laboratory conditions with the idea of pinpointing at which level of humidity there is a change in the speed of evaporation. The quantity of evaporated water is expressed in relative and absolute units of measure.Već dosta dugo Srbija je značajan proizvođač, prerađivač i izvoznik maline. Sa stanovišta primarne proizvodnje možda se može i pohvaliti, čak i ponositi dobrim uspesima. Ipak, sa stanovišta prerade nekako zaostajemo. Razlog je klasična "linija manjeg otpora". Uvek se dovoljno dobro zarađivalo izvozom smrznute maline i niko nije ni pokušavao da istražuje nove proizvode i neke druge atraktivne upotrebne vrednosti od ovog voća. Naime, iako malina ima atraktivnu upotrebnu vrednost (time i značajnu potražnju), poznato je da ima veoma nepovoljna tehnološka svojstva. Malina ima zbirnu cvast, a time i zbirni plod te je veoma osetljiva na mehanička oštećenja. Poznata je i po velikoj brzini tj. po visokoj toploti disanja, te stoga ima kratak period mogućeg čuvanja. Takva svojstva zahtevaju od proizvođača da veoma brzo reaguju sa konzervisanjem ili preradom. Najbrži obrt uloženog kapitala se može postići ako se od plodova dobiju poluproizvodi. Tada su ulaganja najmanja, a smanjen je i rizik po kvalitet. Među poluprerađenim proizvodima od maline, ali i ostalih vrsti voća. svakako su najpoželjniji zamrznuti ili osušeni plodovi. Nažalost, do sada se malo radilo na sušenju maline jer je ona veoma osetljiva kao sirovina i problemi pri sušenju su višestruki. Doduše, postoje i u domaćoj praksi pozitivni rezultati za sušenje smrzavanjem tj. liofilizacijom. U ovom radu je izučavana kinetika sušenja malina u laboratorijskoj sušari sa idejom da se uoči pri kojim sadržajima vlage dolazi do promene brzine isparavanja. Količina isparene vode je izražena u relativnim i apsolutnim jedinicama mere

Novi proizvodi od maline dobijeni liofilizacijom

Freeze drying is relatively new process for drying fruit from frozen state. In distinction from classical drying, freeze drying make product with very little content of water, against maximal preservation of all nutritive matter in the product. These process is especially good for sensitive fruits at whom shall almost save typical flavor, color and vitamins. In this paper oversight of new raspberry products that can bee obtained by freeze drying process is given. Analysis of technological procedures for obtaining of whole freeze dried raspberry and freeze dried raspberry juice in powdered form is given. These technologies are relatively new in the world and with us still are not apply in industrial dimensions. .Liofilizacija predstavlja relativno nov postupak za sušenje iz smrznutog stanja. Za razliku od klasičnog sušenja, liofilizacijom se dobija proizvod sa vrlo malim sadržajem vode uz maksimalno očuvanje svih hranljivih materija u osušenom proizvodu. Ovaj postupak konzervisanja je posebno interesantan za osetljivo voće kod koga treba maksimalno očuvati karakterističnu aromu, boju i vitamine. U radu je data pregled novih proizvoda od maline koji se mogu dobiti postupkom liofilizacije. Data je analiza tehnoloških postupaka za dobijanje liofilizovanog celog ploda maline, kao i liofilizovanih sokova maline u prahu. Ove tehnologije su relativno nove u svetu, a kod nas se još uvek ne primenjuju u industrijskim razmerama.

Antioxidant activity, the content of total phenols and flavonoids in the ethanol extracts of Mentha longifolia (L.) Hudson dried by the use of different techniques

In this study, we have examined the yield of extracted substances obtained by means of extraction using 70 % ethanol (v/v), the content of total phenols and flavonoids, as well as the antioxidant activity of the extracts obtained from the samples of the herbs dried by means of different techniques. Wild mint Mentha longifolia (L.) Hudson was dried naturally in a laboratory oven at a temperature of 45 °C and in an absorptive low temperature condensation oven at 35°C. The highest yield of extracts was obtained from the naturally dried herbs and the lowest from the herbs dried in the low temperature condensation drying oven. The content of total phenols and flavonoids was determined by spectrophotometric methods with an FC reagent and by the complexation reaction with aluminium-chloride, respectively. The extract of the naturally dried herbs had the highest overall content of phenols (113.8±2.0 mg of gallic acid/g of the dry extract) and flavonoids (106.7±0.3 mg of rutin/g of the dry extract). The highest antioxidant activity determined by the FRAP and DPPH assay was determined in the extracts obtained from naturally dried herbs (2.76±0.15 mmol Fe2+/mg of the dry extract and EC50=0.022±0.001 mg/ml), while the lowest was obtained from the extracts of herbs dried in the laboratory oven (1.13±0.11 mmol Fe2+/mg of the dry extract and EC50=0.033±0.001 mg/ml). The HPLC-DAD analysis result show that the greatest content of phenolic compounds show extract obtained from naturally dried plant material. The dominant phenolic component in the all extracts is Kaempferol 3-O-glucoside. The content of all phenolic compound strongly depend on the drying conditions

Essential oils as potential biocontrol products against plant pathogens and weeds: in vitro culture approach

Secondary metabolism in plant plays a major role in the survival of the plant in its ecosystem, mediating the interaction of the plant with its environment. Plant bioactive compounds are biosynthesized as a defensive strategy of plants in response to natural perturbations. A number of biological effects have been associated with the main monoterpenoids detected in investigated Micromeria spp. and Clinopodium spp. essential oils. One alternative for the production of these prospective biocontrol products is in vitro plant tissue culture. Our data suggest that the metabolic potential of in vitro shoot cultures of selected species can be manipulated by varying in vitro culture conditions.“XXVII Savetovanje o biotehnologiji sa međunarodnim učešćem"”, Čačak, 25 - 26. mart 2022. godineSaopštenje je štampano u celosti

Kinetika sušenja jabuke sorte Granny Smith u laboratorijskim uslovima

In the last decade on the world market there is a great interest in dried apple products (publicity-called apple chips). The subject of this paper is the kinetics of the apple cv Granny Smith drying in laboratory dehydrator with the idea of pinpointing at which level of humidity comes to achieving a maximum speed of evaporation and at which level of humidity apple slices are beginning to change in color and geometric shape. The experiment included two temperature regimes of drying, batch process (constant air temperature of 70°C for a period of 8h) and simulated continual process (the air temperature of 70°C for a period of 3 h and the air temperature of 50°C for a period of 5 h). The amount of evaporated water is expressed in relative and absolute units of measure. The purpose of this paper is to optimize the technological process of drying apple slices and in terms of oxidation of polyphenolic compounds to find an adequate temperature treatment which will provide that the final product contains no additives and to be technologically and organoleptically acceptable. The results showed that in simulated continual process of drying the lower maximum speed of drying is achieved, drying is more evenly and in this way the technological process is finished with a smaller temperature stress for plant tissue, resulting in a much better quality of the final product.Poslednjih decenija na svetskom tržištu postoji veliko interesovanje za sušene proizvode od jabuke (marketinški nazvane čips od jabuke). U ovom radu je izučavana kinetika sušenja jabuke sorte Granny Smith u laboratorijskom dehidratoru sa idejom da se uoči pri kojim sadržajima vlage dolazi do postizanja maksimalne brzine isparavanja i pri kojoj vlažnosti kolutovi jabuke počinju da menjaju boju i geometrijski oblik. Primenjena su dva temperaturna režima sušenja: šaržni (konstantna temperatura vazduha od 70 °C u trajanju od 8h) i simulirani kontinualni (temperatura vazduha od 70 °C u trajanju od 3h i temperatura vazduha od 50°C u trajanju od 5h). Količina isparene vode je izražena u relativnim i apsolutnim jedinicama mere. Cilj ovog rada je da se optimizuje tehnološki postupak sušenja kolutova jabuke tako da se, sa aspekta oksidacije polifenolnih jedinjenja, pronađe adekvatni temperaturni režim koji omogućava da gotov proizvod ne sadrži aditive, a da je tehnološki i organoleptički prihvatljiv. Rezultati su pokazali da se pri simuliranom kontinuelnom načinu sušenja postiže manja maksimalna brzina, sušenje je ravnomernije i da se na taj način tehnološki postupak vrši sa manjim temperaturnim stresom za biljno tkivo što rezultira mnogo boljim kvalitetom gotovog proizvoda

Kinetics of drying and quality of the apple cultivars Granny Smith, Idared and Jonagold

Apple is nutritionally valuable and present as fresh fruit in human nutrition throughout the year. Also apple is a raw material in food processing, primarily in the production of juices, nectars, refreshing soft drinks, marmalades, jams, compotes, apple cider vinegar and dried fruits. In the last decade on the world market there is a great interest in dried apple products (commercially called apple chips). During preservation by drying the technological process aimed at the final product of optimal quality is required. The subject of this paper is the kinetics of the apple cv. Granny Smith, cv. Idared and cv. Jonagold drying in laboratory dehydrator for the purpose of pinpointing at which level of humidity the maximum speed of evaporation is achieved and at which level of humidity apple slices begin to change in colour and geometric shape. Parameters of the drying process were the same for all three cultivars, 3hrs at air temperature of 70oC and 5hrs at air temperature of 50o. The amount of evaporated water is expressed in relative and absolute units of measure. The purpose of this paper is to determine which one of the three tested cultivars provides the best properties for drying, i.e. in terms of oxidation of polyphenolic compounds to find the cultivar which will provide that the final product is technologically and organoleptically the most acceptable. The results showed that the sample cv. Granny Smith expressed the least oxidation of polyphenolic compounds (browning), curved edges and shrivelled apple slices. After that the sample cv. Jonagold followed. The sample cv. Idared showed the worst results. Following the drying kinetics of all three samples, it can be concluded that the cultivars Granny Smith and Jonagold were achieving the lower maximum speed of evaporation, unlike the cultivar Idared. The cultivars Granny Smith and Jonagold have attained consistent drying and in this way the technological process was finished with a smaller temperature stress for plant tissue, resulting in a much better quality of the final product