<p>Valorizacija permeata kao sporednog proizvoda industrije mleka je od izuzetnog ekološkog, ekonomskog i tehnološkog značaja.<br />Cilj doktorske disertacije je razvoj tehnološkog procesa prerade permeata, kao sporednog proizvoda dobijenog nakon ultrafiltracije mleka tokom proizvodnje feta sira i svežeg („mladog“) sira. Ispitana je mogućnost enzimske hidrolize laktoze u permeatu korišćenjem enzima β-galaktozidaze izolovanog iz Kluyveromyces lactis u koncentraciji 0,1, 0,3 i 0,5 g/100g na temperaturama 20º, 30º i 40 ºC. Praćene su promene sadržaja laktoze, D–galaktoze i D–glukoze u vremenskim intervalima tokom 60 minuta. Posebna faza istraživanja obuhvatila je matematičko modelovanje i kinetiku procesa hidrolize laktoze u permeatu pod dejstvom β –galaktozidaze i primenu hidrolizovanog permeata u proizvodnji mlečnih napitaka po odabranoj formulaciji. Predložen je tehnološki proces proizvodnje napitka na bazi hidrolizovanog permeata sa dodatkom voćnih baza. Utvrđeni su parametri kvaliteta i trajnosti napitaka tokom 60 dana skladištenja.<br />Na temperaturi 40°C dodatkom enzima β -galaktozidaze u koncentraciji 0,1g/100g za 60 minuta postiže se 100% stepen hidrolize prisutne laktoze u permeatu. Sa većom koncentracijom enzima, 0,3 g/100g odnosno 0,5g/100g, na istoj temperaturi, isti efekat se postiže za 20 minuta.<br />Ispitivanjem kinetike hidrolize laktoze potvrđena je kinetika prvog reda. Generalno posmatrano visoki koeficijenti determinacije pokazuju dobro poklapanje eksperimentalnih rezultata i matematičkog modela reakcije prvog reda. Vrednosti se kreću od 0,974 (temperatura 20°C) do preko 0,990 (na temperaturama 30°C i 40°C) pri koncentraciji enzima 0,1g/100g.<br />Proizvedeni napici od hidrolizovanog permeata su delaktozirani i ne sadrže mlečnu mast. Od ukupnih šećera u svim napicima više od 50% čini glukoza: 50,16% - napitak šumsko voće, 50,42% - napitak pomorandža/šargarepa, 54,65% - napitak multivitamin, odnosno 55,13% - napitak crveno voće.<br />Najveći sadržaj vitamina C nakon proizvodnje imao je napitak sa dodatkom voćne baze multivitamin 0,3972 mg/100g, zatim šumsko voće 0,2887 mg/100g i pomo-randža/šargarepa 0,1999 mg/100g.<br />Najveću vrednost antioksidativne aktivnosti nakon proizvodnje pokazali su uzorci napitka sa multivitaminom i šumskim voćem. Tokom perioda skladištenja dolazi do smanjenja DPPH vrednosti. Najmanji pad je u napitku sa pomorandžom / šargarepom (smanjenje za 17%), a najveći u napitku sa šumskim voćem (za 39%). Analizirani uzorci sadrže ukupnih polifenola u intervalu od 47,84 do 120,38 mg GAE/l u zavisnosti od vrste napitka, odnosno dodatih voćnih baza.<br />Generalno može se zaključiti da se prime-njenim tehnološkim procesom dobijaju napici stabilnog fizičko-hemijskog sastava tokom 60 dana skladištenja, visoke nutritivne i niske energetske vrednosti.</p> / <p>Valuation of the permeate as a by-product of the dairy industry is of great ecological, economic and technological importance.<br />The aim of the PhD thesis is the development of the technological process of refining permeate, as a by-product obtained after ultrafiltration of milk during the production of feta cheese and fresh cheese. The possibility of enzymatic hydrolysis of the lactose in the permeate using the enzyme β-galactosidase isolated from Kluyveromyces lactis in a concentration of 0.1, 0.3 and 0.5 g / 100 g at a temperature of 20°, 30° and 40° C was examined. Changes in the content of lactose, D-galactose and D-glucose at intervals of 60 minutes were monitored. A special stage of the research included mathematical modeling and kinetics of lactose hydrolysis in the permeate under the influence of β-galactosidase and application of hydrolyzed permeate in the production of dairy products under the selected formulation. A technological process of producing a beverage on the basis of hydrolyzed permeate with the addition of fruit bases was suggested. Quality and durability parameters were determined for drinks during the 60 days of storage.<br />Addition of the enzyme β-galactosidase at a concentration of 0.1 g / 100 g for 60 minutes at a temperature of 40 ° C a 100% degree of hydrolysis of lactose is achieved, present in the permeate. With a higher concentration of enzyme, 0.3 g / 100 g or 0.5 g / 100g, at the same temperature, the same effect can be achieved in 20 minutes.<br />By examining the kinetics of lactose hydrolysis the first order kinetics was confirmed. Generally high coefficients of determination show good correspondence between the experimental results and the mathematical model of the first order reaction. Values range from 0.974 (at a temperature of 20° C) up to over 0.990 (at temperatures 30° C and 40° C) at a an enzyme concentration of 0.1g / 100g.<br />Beverages produced from hydrolyzed permeate are lactose-free and fat-free products. More than half of the total sugar content in all beverages consists of glucose: 50.16%-forest fruit beverage, 50.42%-beverage orange/carrot, 54.65% beverage multivitamin and 55.13% - beverage red fruit.<br />The highest vitamin C content after production was in a beverage with the addition of fruit base multivitamin (0.3972 mg/100g), followed by forest fruit (0.2887 mg/100g) and orange/carrot (0.1999 mg/100g).<br />Beverage samples with multivitamin and forest fruits showed the highest value of antioxidant activity after production. During the storage period there is a reduction of DPPH values. The smallest decrease was in the beverage with orange/carrot (decreased 17%), and the biggest in the beverage with forest fruit (39%). The content of polyphenols in analyzed samples ranges from 47.84 to 120.38 mg GAE/L depending on the type of beverage and added fruit base.<br />Overall it can be concluded that the applied technological process gives beverages of stable physical and chemical content during the 60 days of storage, of high nutritional value and low energy.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)95728 |
| Date | 18 December 2015 |
| Creators | Ilić-Udovičić Dragana |
| Contributors | Milanovic Spasenija, Carić Marijana, Iličić Mirela, Jokić Aleksandar, Mandić Anamarija |
| Publisher | Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, University of Novi Sad, Faculty of Technology at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | English |
| Type | PhD thesis |
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