Uticaj sadržaja suve materije i količine dodatog indikatora fenolftaleina na titracionu kiselost i pH mleka

In this work, the dynamic of titratable acidity growth with incrising of solids non fat content (SNF) in samples of reconstituted milk was researched. The SNF content was adjusted on 4 levels: 7,5% (samples A), 8% (samples B); 8,5% (samples C) and 9% (samples D). The influence of phenolphthalein addition in quantity of 3 drops, 5 drops and 1 ml on titratable acidity was also researched. Results of the research show linear increase of titratable acidity with increasing of SNF content. On the other hand, the titratable acidity was declining with the increase of indicator addition. For example: titratable acidity of A samples, which were examined with 1 ml additional indicator, has been 1,18°SH lower than acidity of the same samples in which 3 drops of indicator were added. The change of pH value has been insignificant compared to titrable acidity changes with the increase of indicator addition.U radu je ispitivana dinamika porasta titracione kiselosti sa povećanjem sadržaja suve materije bez masti (SMBM) u uzorcima od rekonstituisanog obranog mleka u prahu. Sadržaj SMBM je podešen na 7,5% (uzorci A), 8% (uzorci B), 8,5% (uzorci C) i 9% SMBM (uzorci D). Paralelno s tim je ispitivan uticaj količine dodatog indikatora fenolftaleina, koji je u količini od 3 kapi, 5 kapi i 1 ml dodavan prilikom određivanja titracione kiselosti modifikovanom metodom Soxlet-Henkela (metoda po Morresu). Na osnovu rezultata istraživanja može se uočiti linearan porast titracione kiselosti sa povećanjem sadržaja SMBM. S druge strane, kada se posmatra uticaj količine dodatog indikatora, može se ustanoviti značajno opadanje titracione kiselosti sa povećanjem količine indikatora. Ukoliko se prilikom titracione metode koristi 1 ml fenolftaleina kao indikatora, rezultati su pokazali znatno niže vrednosti titracione kiselosti u odnosu na količinu dodatog indikatora od 3 i 5 kapi fenolftaleina. Najveća razlika uočava se prilikom titracije uzoraka sa 7,5% SMBM, gde su vrednosti za titracionu kiselost bile čak za 1,18°SH (19,19%) niže kada je uzorcima dodavano 1 ml u odnosu na one kojima je dodavano 3 kapi fenolftaleina. Što se promene pH vrednosti tiče, rezultati istraživanja su pokazali neznatan pad pH (u proseku za 0,03 pH jedinice) sa povećanjem količine dodatog indikatora sa 3 na 5 kapi, dok je prilikom dodavanja 1 ml fenolftaleina pad pH vrednosti bio nešto viši (0,3 pH jedinice)

Randman različitih varijeteta sireva u tipu gorgonzole

The yield and the weight loss in the production of two Gorgonzola-type cheese varieties were examined in this paper. The two varieties, with commercial names "Blue sapphire" and 'Blue birch', were produced from pasteurized cow milk, using two types of Penicillium roqueforti (type esportazione and type dolce, respectively). The production was held in PIQ3 Agroengineering Belgrade. The cheese weight was measured 1 day after self pressing, than after salting and 14, 30 and 60 days of ripening. According to results, the yield of both 60 days old varieties was -10%, i.e. for the production of 1 kg of cheese was used -10 liters of milk. Considering the fact that the proteolytical changes in "Blue birch" variety were higher, the weight loss of 60 days old samples was -15%, comparing to -13% in "Blue sapphire" variety.U radu je prikazano ispitivanje randmana i kala u proizvodnji dva varijeteta sireva sa plavo-zelenim plesnima u tipu gorgonzole, proizvedenih u pogonu DP. PKB Agroinzenjering, Beograd. Ogledni sirevi, čiji su komercijalni nazivi "plavi safir" i "plava breza", proizvedeni su od pasterizovanog kravljeg mleka upotrebom dva tipa kulture plasni Penicillium roqueforti (tip esportazione i tip dolce, respektivno). Merenje mase sireva vršeno je 1 dan nakon samopresovanja, zatim soljenja i nakon 14, 30 i 60 dana zrenja. Prema rezultatima istraživanja, randman oba varijeteta nakon 60 dana zrenja bio je približno isti (-10%), odnosno za izradu 1 kg sira bilo je potrebno utrošiti -10 litara mleka. Međutim, s obzirom na intenzivnije promene na proteinima u uzorcima varijeteta "plava breza", kalo nakon 60 dana zrenja iznosio je -15%, dok je Rod uzoraka.plavi safir" iznosio -13%

Poboljšanje metaboličke aktivnosti bakterije Lactobacillus plantarum 564 pomoću elektroporacije

The exposure of bacterial cells to pulsed electric fields (PEF) leads to the reversible formation of pores in the cell membrane if an applied energy is below the critical level. Therefore, the effect of electric field pulses with amplitudes below 14 kV/cm and the applied energy up to 12.2 J/cm3 on the growth of Lactobacillus plantarum 564 cells was investigated. After PEF treatments, the growth of lactobacilli in De Man-Rogosa-Sharpe broth at 37 °C was monitored by isothermal calorimetry, absorbance and plate counts. All the applied treatments resulted in a higher growth rate of PEF-treated cells during early and mid-log phase, especially bacterial samples treated with lower field intensities (1.3–5.5 J/cm3). The transport of ions and molecules through the cell membrane (which facilitates the growth of electroporated lactobacilli) was particularly evident in the mid-exponential growth phase, where the doubling time was reduced more than 3 times after the exposure to electric pulses of 5.5 J/cm3. The heat production rate during the growth of electroporated cells was also higher, indicating the enhanced metabolic activity of PEF-treated cells. Moreover, the electroporated cells had a better acidification ability than the untreated ones. It can be summarized that the applied PEF treatments with an energy input of below 12 J/cm3 potentially induce reversible electroporation of the cell membrane, which has a positive impact on the growth and metabolic activity of the cells of lactobacilli.Izlaganje bakterija pulsirajućim električnim poljima uzrokuje reverzibilno stvaranje pora na staničnoj membrani, ako je energija električnog polja ispod kritične razine. Stoga je istražen utjecaj pulsirajućih električnih polja na rast stanica bakterije Lactobacillus plantarum 564 primjenom polja jačine do 12.2 J/cm3, tj. amplituda manjih od 14 kV/cm. Rast laktobacila u De Man-Rogosa-Sharpe bujonu na 37 °C nakon tretmana praćen je pomoću izotermalne kalorimetrije, te mjerenjem apsorbancije i ukupnog broja stanica. Utvrđeno je da su stanice izložene pulsirajućem električnom polju brže rasle tijekom rane i srednje logaritamske faze, što je naročito bilo izraženo kod stanica tretiranih poljima niskog intenziteta (1.3-5.5 J/cm3). Transport iona i molekula kroz staničnu membranu (što olakšava rast elektroporiranih laktobacila) bio je posebno izražen tijekom eksponencijalne faze rasta, kad je generacijsko vrijeme stanica tretiranih pulsevima energije od 5.5 J/cm3 bilo trostruko kraće. Tijekom rasta tretiranih stanica oslobođena je veća količina topline, što znači da se metabolička aktivnost stanica povećala nakon tretmana. Osim toga, elektroporirane su stanice jače zakiseljavale sredinu. Iz dobivenih se rezultata može zaključiti da pulsirajuća električna polja jačine manje od 12.2 J/cm3 uzrokuju reverzibilnu elektroporaciju stanične membrane, što ima pozitivan učinak na rast i metaboličku aktivnost stanica laktobacila

Uticaj sadržaja SMBM i proteinskog preparata 'ALACO 6206' na indukovani sinerezis kiselog kazeinskog gela

In this work, the influence of solids non fat content (SNF) and milk protein based ingredient ALACO 6202 on induced syneresis of acid casein gel was investigated. Reconstituted skim milk powder was used as substratum. The SNF content was adjusted on 3 levels: 9.0% (samples A), 9.5% (samples B) and 10% (samples C). The influence of different SNF content on induced syneresis of acid casein gel was the first part of the research. In the second part of investigation, the SNF content was standardized as follows: the concentration of milk protein based ingredient ALACO 6202 was adjusted on 1.0% (samples A-1), 1.5% (samples B-1) and 2.0% (samples C-1), including 8% of skim milk powder concentration in each sample. The centrifugation of samples was performed at 1000, 2000 and 3000 revolutions/min in 10 minutes. The percent of separated serum (%w/w) at 1000 revolutions/min was 6.03%, 10.07% and 1.59% for samples A, B and C retrospectively, and there was no separated serum in semples A-1, B-1 and C-1. The amount of serum separated at 2000 revolutions/min in samples A, B, C, A-1, B-1 and C-1 was 37.59%, 31.65% 24.67%, 18.59%, 12.28% i 10.52% retrospectively, and at 3000 revolutions/min was 59.17%, 54.62%, 35.41%, 33.95%. 27.66 and 14.61% retrospectively. It was concluded that the increase of centrifugal force causes the increase of syneresis of acid casein gel, while the increase of SNF content reduces the syneresis at all centrifugal forces applied. However, the addition of milk protein based ingredient ALACO 6202 reduces the syneresis, so this protein ingredient could be used for improving rheological characteristics of fermented products.U radu je ispitivan uticaj sadržaja suve materije bez masti (SMBM), kao i proteinskog preparata ALACO 6202 na indukovani sinerezis kiselog kazeinskog gela, a kao supstrat za oglede korišćeno je rekonstituisano obrano mleko u prahu, pri čemu je vršena standardizacija na 9.0% (uzorci A), 9.5% (uzorci B) i 10.0% SMBM (uzorci C). Prvi deo istraživanja baziran je na ispitivanju uticaja različitog sadržaja SMBM na indukovani sinerezis kiselog kazeinskog gela, a u drugom delu istraživanja vršena je standardizacija sadržaja SMBM uz dodatak proteinskog preparata ALACO 6202 u koncentracijama od 1.0% (uzorci A-1), 1.5% (uzorci B-1) i 2.0% (uzorci C-1), dok je sadržaj obranog mleka u prahu standardizovan na 8%. Uzorci su centrifugirani pri brzinama od 1000 2000 i 3000 o/min u trajanju od 10 min, pri čemu je procenat izdvojenog seruma (W/W) pri 1000 o/min iznosio: 6.03%, 10.07%, 1.59% za uzorke A, B i C retrospektivno, dok se kod uzoraka koji su sadržali proteinski preparat serum nije izdvojio. Pri brzini od 2000 o/min količina izdvojenog seruma kod uzoraka A, B, C, A-1, B-1 i C-1 retrospektivno je iznosila: 37.59%, 31.65% 24.67%, 18.59%, 12.28% i 10.52%, dok je pri brzini od 3000 o/min iznosila 59.17%, 54.62%, 35.41%, 33.95%, 27.66% i 14.61%. Na osnovu rezultata može se zaključiti da sa povećanjem centrifugalne sile raste i sinerezis kiselog kazeinskog gela, dok se povećanjem sadržaja SMBM sinerezis smanjuje pri svim primenjenim centrifugalnim silama. Međutim, dodatkom proteinskog preparata ALACO 6202 izdvajanje seruma je znatno manje, pa se stoga pomenuti preparat može koristiti kao sredstvo za poboljšanje reoloških karakteristika kiselo-mlečnih proizvoda

Distribucija sastojaka mleka pri proizvodnji sireva sa plavo-zelenim plesnima u tipu gorgonzole

Blue-veined cheeses in type of Gorgonzola with commercial names "Blue sapphire" and "Blue birch" were made from pasteurized cow milk using two types of Penicillium roqueforti, type esportazione and type dolce respectively. In this paper, the distribution of milk components into cheese and cheese whey was examined. The samples of whey were taken in 3 phases after the cutting of coagulum, after 50% of whey drainage and at the end of drainage, where the samples have labeled as whey 1, 2 and 3. The distribution of total solids, milk fat, proteins and mineral matters from milk to cheese after production and cheese whey was examined. According to results, about 46% of total solids, 82% of milk fat, 65% of proteins and 37% of mineral matters have transferred from milk to "Blue sapphire" cheese, while the distribution of the same constituents into "Blue birch" cheese was ca. 49% 87%, 67% and 35%, respectively.Sirevi sa plavo-zelenim plesnima u tipu Gorgonzole pod nazivom "Plavi safir" i "Plava breza" proizvedeni su od pasteizovanog kravljeg mleka, koristeći dva tipa kulture plasni Penicillium roqueforti, i to tip esportazione i tip dolce, respektivno. U radu je ispitivan stepen distribucije sastojaka mleka u sir i surutku koja se prilikom izrade sira uzorkovala u tri faze: odmah nakon sečenja gruša, zatim nakon odlivanja 50% surutke i na samom kraju odlivanja surutke, pri čemu su uzorci surutke obeležavani kao surutka 1, 2 i 3. Praćen je stepen distribucije sadržaja suve materije, mlečne masti, proteina i mineralnih materija u sir nakon proizvodnje i u surutku. Prema rezultatima istraživanja, oko 46% suve materije, 82% mlečne masti, 65% proteina i 37% mineralnih materija je prešlo u sir "Plavi safir", dok je stepen distribucije istih sastojaka u sir "Plava breza" iznosio oko 49%, 87%, 67% i 35% respektivno

Zlatarski sir - autohtona tehnologija i senzorne karakteristike

Zlatar cheese is one of the most famous autochthonous dairy products in Serbia. It is produced in the area of mountain Zlatar by autochthonous technology. One of the main characteristics of autochthonous Zlatar cheese is that it is produced from full fat cow milk. According to MFFB content all samples of Zlatar cheese belong to soft cheeses group, and by FTS content they belong to a group of full fat cheeses. Sensory analysis of cheeses involved evaluation of appearance, color, cross section, flavor, aroma and consistency. By this analysis cheeses were ranked in five categories: excellent, very good, good, positive and negative. Total number of examined samples was 149.Zlatarski sir je jedan od najpoznatijih autohtonih mlečnih proizvoda u Srbiji. Proizvodi se od punomasnog kravljeg mleka po autohtonoj tehnologiji u podnožju Zlatara, u okolini Nove Varoši. Po sadržaju VBMS sirevi pripadaju grupi mekih sireva, a po sadržaju MuSM svi ispitani uzorci zlatarskog sira svrstani su u grupu punomasnih sireva. Senzornom analizom kojom je ocenjen opšti izgled, boja, presek, ukus, miris i konzistencija, uzorci sira svrstani su u pet kategorija: odličan, vrlo dobar, dobar, zadovoljava i ne zadovoljava. Ukupno je ocenjeno 149 uzoraka zlatarskog sira

The Sensory Quality and Volatile Profile of Dark Chocolate Enriched with Encapsulated Probiotic Lactobacillus plantarum Bacteria

peer-reviewedCocoa and dark chocolate have a wide variety of powerful antioxidants and other nutrients that can positively affect human health. Probiotic dark chocolate has the potential to be a new product in the growing number of functional foods. In this study, encapsulated potential probiotic Lactobacillus plantarum 564 and commercial probiotic Lactobacillus plantarum 299v were added in the production of dark chocolate. The results show very good survival of probiotic bacteria after production and during storage, reaching 108 cfu/g in the first 60 days and over 106 cfu/g up to 180 days. No statistically significant difference (p > 0.05) in chemical composition and no major differences in the volatile profiles between control and experimental chocolate samples were observed, indicating no impact of probiotic bacteria on compositional and sensory characteristics of dark chocolate. The sensory evaluation of control and both probiotic dark chocolate samples showed excellent sensory quality after 60 and 180 days of storage, demonstrating that probiotics did not affect aroma, texture and appearance of chocolate. Due to a high viability of bacterial cells and acceptable sensory properties, it can be concluded that encapsulated probiotics Lb. plantarum 564 and Lb. plantarum 299v could be successfully used in the production of probiotic dark chocolate

Uticaj pulsirajućih električnih polja na rast i aktivnost autohtonog soja Lactobacillus plantarum 564

Ponašanje preživele populacije ćelija soja Lb. plantarum 564 zasejane u MRS bujonu nakon dejstva pulsirajućih električnih polja (PEP) različitog intenziteta, praćeno je putem izotermalne kalorimetrije, merenjem optičke gustine i ukupnog broja ćelija. Ćelije bakterija su tretirane monopolarnim pulsevima pravugaonog oblika različite jačine i broja pulseva, što odgovara primenjenoj energiji od 1.3, 5.5, 12.2, 34.6, 65.8 and 658.1 J/cm3. Nakon PEP tretmana, bakterije su inokulisane u MRS bujon i inkubirane na 37°C u toku 24 sata. Rezultati istraživanja su pokazali da su PEP tretmani energije ispod 13 J/cm3 imali pozitivan efekat na rast i aktivnost ćelija, naročito tretmani niže energije (1.3-5.5 J/cm3). Prisustvo intracelulatnih jona i molekula u medijumu, koji pozitivno utiču na rast ćelija, bilo je posebno izraženo u mid-eksponencijalnoj fazi rasta, gde je generaciono vreme ćelija tretiranih pulsevima energije 5.5 J/cm3 bilo trostruko skraćeno. Stepen odavanja toplote oslobođene tokom rasta ćelija takođe je bio viši, što ukazuje na porast metaboličke aktivnosti PEP tretiranih ćelija, čija je acidifikaciona sposobnost takođe bila povećana. Pretpostavlja se da PEP tretmani nižeg intenziteta dovode do reverzibilne elektroporermeabilizacije ćelija, čija je vijabilnost ostala nepromenjena nakon izlaganja pulsevima energije 12.2 J/cm3, što znači da se ovi procesni parametri nalaze ispod kritične vrednosti potrebne za inaktivaciju ispitivanih laktobacila. Primena jačih PEP tretmana energije 34.6, 65.1 and 658.1 J/cm3 je dovela do inaktivacije ćelija za oko 1, 2 i 3 log redukcije, respektivno. U zavisnosti od jačine primenjenog tretmana, preživeli deo populacije Lb. plantarum 564 je nastavio da raste sa određenim zakašnjenjem, pri čemu je nova populacija formirala istu gustinu u MRS bujonu kao i populacija netretiranih ćelija. Tretirane ćelije su pokazale brži stepen rasta u kasnoj log-fazi, mada je trend rasta bio sličan kao kod netretiranih. Preživela subpopulacija ukazuje na prisustvo perzistera otpornih na dejstvo PEP tretmana...The behaviour of a surviving population of lactic acid bacteria strain Lactobacillus plantarum 564 growing in MRS broth after pulsed electric field (PEF) treatments of different intensities was monitored by isothermal calorimetry, optical density and plate counts. Bacterial cells were treated with monopolar square pulses at varying nominal electric field strengths and number of pulses, corresponding to applied energies of 1.33, 5.5, 12.2, 34.6, 65.8 and 658.1 J/cm3. After PEF treatments, samples were inoculated into MRS broth and incubated at 37°C for 24 hours. The presented results show that the PEF treatments with energy input below 13 J/cm3 had a positive effect on bacterial growth and cell activity, especially the treatments with the lower field intensities (1.3 – 5.5 J/cm3). The presence of intracellular ions and molecules in media that facilitates the growth of electroporated lactobacilli was particularly evident in mid-exponential growth phase, where the doubling time was reduced for more than 3 times after the exposure to electric pulses of 5.5 J/cm3. The heat production rate released during the growth of electroporated cells was also higher, indicating the enhanced metabollic activity of PEF treated cells. Also, the electroporated cells had better acidification ability than the untreated cells. It is assumed that the applied PEF treatments with an energy input of below 13 J/cm3 potentially induce reversible electroporation of the cell membrane, which has a positive impact on the cell growth. The viability of cells remained unaffected by pulse energy of 12.2 J/cm3, which means that such treatment conditions remained below the critical field strength for the inactivation of treated lactobacilli. The PEF treatments with higher energy of 34.6, 65.1 and 658.1 J/cm3 induced cell inactivation of approx. 1, 2 and 3 log reduction, respectively. After the application of pulses to a population of Lb. plantarum 564, the survived bacterial cells resume growth after a treatment-dependent delay. A new population density is obtained at the same final level as the original culture. Both the untreated and treated culture had similar growth rates, but the latter showed a higher growth rate during the late-growth phase. Evidence of bacterial persistence is shown on the survived population of bacteria subjected to PEF treatment..

Uticaj pulsirajućih električnih polja na rast i aktivnost autohtonog soja Lactobacillus plantarum 564

Ponašanje preživele populacije ćelija soja Lb. plantarum 564 zasejane u MRS bujonu nakon dejstva pulsirajućih električnih polja (PEP) različitog intenziteta, praćeno je putem izotermalne kalorimetrije, merenjem optičke gustine i ukupnog broja ćelija. Ćelije bakterija su tretirane monopolarnim pulsevima pravugaonog oblika različite jačine i broja pulseva, što odgovara primenjenoj energiji od 1.3, 5.5, 12.2, 34.6, 65.8 and 658.1 J/cm3. Nakon PEP tretmana, bakterije su inokulisane u MRS bujon i inkubirane na 37°C u toku 24 sata. Rezultati istraživanja su pokazali da su PEP tretmani energije ispod 13 J/cm3 imali pozitivan efekat na rast i aktivnost ćelija, naročito tretmani niže energije (1.3-5.5 J/cm3). Prisustvo intracelulatnih jona i molekula u medijumu, koji pozitivno utiču na rast ćelija, bilo je posebno izraženo u mid-eksponencijalnoj fazi rasta, gde je generaciono vreme ćelija tretiranih pulsevima energije 5.5 J/cm3 bilo trostruko skraćeno. Stepen odavanja toplote oslobođene tokom rasta ćelija takođe je bio viši, što ukazuje na porast metaboličke aktivnosti PEP tretiranih ćelija, čija je acidifikaciona sposobnost takođe bila povećana. Pretpostavlja se da PEP tretmani nižeg intenziteta dovode do reverzibilne elektroporermeabilizacije ćelija, čija je vijabilnost ostala nepromenjena nakon izlaganja pulsevima energije 12.2 J/cm3, što znači da se ovi procesni parametri nalaze ispod kritične vrednosti potrebne za inaktivaciju ispitivanih laktobacila. Primena jačih PEP tretmana energije 34.6, 65.1 and 658.1 J/cm3 je dovela do inaktivacije ćelija za oko 1, 2 i 3 log redukcije, respektivno. U zavisnosti od jačine primenjenog tretmana, preživeli deo populacije Lb. plantarum 564 je nastavio da raste sa određenim zakašnjenjem, pri čemu je nova populacija formirala istu gustinu u MRS bujonu kao i populacija netretiranih ćelija. Tretirane ćelije su pokazale brži stepen rasta u kasnoj log-fazi, mada je trend rasta bio sličan kao kod netretiranih. Preživela subpopulacija ukazuje na prisustvo perzistera otpornih na dejstvo PEP tretmana...The behaviour of a surviving population of lactic acid bacteria strain Lactobacillus plantarum 564 growing in MRS broth after pulsed electric field (PEF) treatments of different intensities was monitored by isothermal calorimetry, optical density and plate counts. Bacterial cells were treated with monopolar square pulses at varying nominal electric field strengths and number of pulses, corresponding to applied energies of 1.33, 5.5, 12.2, 34.6, 65.8 and 658.1 J/cm3. After PEF treatments, samples were inoculated into MRS broth and incubated at 37°C for 24 hours. The presented results show that the PEF treatments with energy input below 13 J/cm3 had a positive effect on bacterial growth and cell activity, especially the treatments with the lower field intensities (1.3 – 5.5 J/cm3). The presence of intracellular ions and molecules in media that facilitates the growth of electroporated lactobacilli was particularly evident in mid-exponential growth phase, where the doubling time was reduced for more than 3 times after the exposure to electric pulses of 5.5 J/cm3. The heat production rate released during the growth of electroporated cells was also higher, indicating the enhanced metabollic activity of PEF treated cells. Also, the electroporated cells had better acidification ability than the untreated cells. It is assumed that the applied PEF treatments with an energy input of below 13 J/cm3 potentially induce reversible electroporation of the cell membrane, which has a positive impact on the cell growth. The viability of cells remained unaffected by pulse energy of 12.2 J/cm3, which means that such treatment conditions remained below the critical field strength for the inactivation of treated lactobacilli. The PEF treatments with higher energy of 34.6, 65.1 and 658.1 J/cm3 induced cell inactivation of approx. 1, 2 and 3 log reduction, respectively. After the application of pulses to a population of Lb. plantarum 564, the survived bacterial cells resume growth after a treatment-dependent delay. A new population density is obtained at the same final level as the original culture. Both the untreated and treated culture had similar growth rates, but the latter showed a higher growth rate during the late-growth phase. Evidence of bacterial persistence is shown on the survived population of bacteria subjected to PEF treatment..