Metode određivanja proteina u mlijeku

U suvremenoj mljekarskoj industriji potrebna je stalna kontrola glavnih sastojaka mlijeka. U većini mljekara, mlijeko se plaća prema sadržaju masti, što stimulira proizvođače na povećanje postotka masti u mlijeku

Sensory evaluation of dessert milk products

Kvalitetu gotovog proizvoda obilježava niz faktora, a jedan od njih je i nivo senzorske poželjnosti. Od velike je važnosti za osiguranje plasmana novih proizvoda na tržištu saznanje o tome kako ih prihvaćaju potrošači. U ovom radu istraživane su dvije vrste mliječnih desertnih proizvoda na bazi proteina sirutke. Šezdeset potrošača testiralo je uzorke koristeći hedonističku skalu od 9 mogućih odgovora (ocjena). Senzorska kvaliteta je također procijenjena primjenom sistema bodovanja koristeći faktore značaja na skali od 20 bodova. Svježi uzorci i uzorci čuvani u uvjetima hladnjaka (4 °C, 85% rel. vlažnosti) ocjenjivani su svakih 7 dana (u razdoblju od 35 dana) u uvjetima temperature 20 °C. Bodovanje je provela panel grupa od 5 članova. Podaci su statistički obrađeni i interpretirani. Rezultati hedonističke skale pokazali su da ih potrošači smatraju vrlo poželjnim (preko 95%). Sistem bodovanja korišten u senzorskoj procjeni pokazao je da dolazi do značajnih promjena u kvaliteti za vrijeme skladištenja, ali one nisu toliko brze i velike da bi proizvod nakon 35 dana skladištenja bio senzorski neprihvatljiv (<11,2 boda). Može se zaključiti da je nivo kvalitete istraživanih uzoraka vrlo visok prema procjeni potrošača i senzorskih analitičara.The quality of a product is compromise between many factors, one of which is high level of sensory appeal Of major importance among factors determining marketing success of a new food product is consumers\u27 acceptability. Two kinds of new dessert milk products based on whey proteins were studied. Consumers (60 persons) tasted samples using nine-point hedonic scale. Quality was evaluated as well using sensory scoring method and 20-point scale. Fresh samples and cold stored samples (4 °C, 85% R. H.) were evaluated every 7 days (during 35 days) at room temperature (20 °C) by a panel composed of 5 members. Data of sensory and hedonic evaluation of quality were statistically analyzed. The results of hedonic scale application showed high consumers acceptability (above 95%) of new products. Sensory scoring pointed out significant changes in quality of both soft albumin cheeses during storage, that was not fast and strong enough to reach cut-off level (<11,2 points) during 35 days of storage. Concluding it is possible to state that quality level of new products was very high as according to consumers \u27or sensory analitcs\u27 opinion

Primjena enzimskih metoda u kontroli kvalitete mliječnih proizvoda

Mlijeko kao i mliječne prerađevine zauzimaju sve značajnije mjesto u ishrani ljudi. S jedne strane mliječni proizvodi odgovaraju zahtjevima suvremene medicine, a s druge strane suvremena tehnologija proizvodnje, obrade i prerade mlijeka smanjila je mogućnost kvarenja ovih proizvoda, a time povećala trajnost

Senzory evaluation of cheese quality by scoring system

Za procjenu kakvoće prehrambenih proizvoda koristi se niz metoda, medu kojima senzorske metode zauzimaju sve značajnije mjesto. U ovom radu prikazana je praktična provedba senzorske procjene uzoraka mekih i polutvrdih sireva sistemom ponderiranih bodova. Izrađene su potrebne ocjenjivačke liste za svaku grupu istraživačkih uzoraka, u koje su unesena odgovarajuća svojstva (parametri kvalitete), zahtjevi za kakvoćom izraženi odgovarajućom ocjenom, kao i "faktori značaja". Istraživanje je obuhvatilo uzorke mekih sireva s plemenitim plijesnima tipa "Camembert" i uzorke polutvrdih sireva tipa "Trapist" različitih jugoslavenskih proizvođača. Ocjenjivanje je provela grupa od 5 senzorskih analitičara ("penel") i to u dva uzastopna zasjedanja. Rezultati su statistički interpretirani, utvrđena je preciznost i pouzdanost ispitivača, a uzorci su, na temelju postignutih bodova, svrstani u odgovarajuće kategorije kvalitete.Numerous methods are used, for quality evaluation of food products, sen-soric evaluation being one of more significant. Practical realization of sensoric evaluation of soft (type Camembert) and semi-hard (trapist) cheese samples is presented using scoring system (20-poin-ts scale) and ponderable factors. Property sheets were made for each group of cheese samples. Scored quality parameters were evaluated in two successive session by a panel of 5 experts. Results are statistically interpreted, precision and ability of the assessors established and samples classified in quality categories according to achieved scores

Consumers\u27 acceptability of commercial plain yogurt using hedonic scale

Grupa potrošača (70 članova) ocjenjivala je prihvatljivost uzoraka jogurta sa zagrebačkog tržišta. Istraživanjem su obuhvaćeni odgovori grupe potrošača za opći utisak te za vanjski izgled, konzistenciju, slatkost i kiselost, koristeći hedonističku skalu s 9 mogućih odgovora. Ocjene potrošača za opći utisak uspoređivane su s ocjenama za ostale parametre i izračunate su odgovarajuće korelacije. Provedena je statistička analiza rezultata. Ocjene potrošača za opći utisak kretale su se od 6,7 do 7,8. Uzorci su bili značajno različiti (P = 0,05). Vanjski izgled uzorka bio je ocijenjen od 6,6 do 7,6; konzistencija od 6,4 do 8,0; slatkost od 6.1 do 7.6: a kiselost od 6,5 do 7,5. Utvrđena je pozitivna korelacija između ocjena za opći utisak i ocjena za konzistenciju, slatkost i kiselost. Slabije je izražena korelacija općeg utiska i vanjskog izgleda. Rezultati provedenog istraživanja pokazuju da su potrošači vrlo dobro prihvatili sve uzorke (88,6 do 100,0%).Consumers (70 members) evaluated commercial plain yogurt for acceptance on the Zagreb market. Objectives included determination of consumers\u27 panel responses for overall liking, appearance, consistency, sweetness and sourness using a nine-point hedonic scale. Consumers\u27 responses for overall liking were correlated with other attribute ratings. The data were analyzed statistically. Consumer hedonic scores for overall liking varied from 6.7 to 7.8. Samples were significantly different (P= 0.05). Appearance liking ranged from 6.6 to 7.6; consistency varied from 6.4 to 8.0. Sweetness and sourness showed values from. 6.1-7.6 and 6.5-7.5 respectively. Hedonic ratings for consistency, sweetness and sourness positively correlated with overall liking. Overall liking showed the lowest correlation with appearance liking. The results of hedonic scale showed high consumer acceptability for all samples (ranged from 88.6 to 100.0%)

Aspergillus piperis a/5 from plum-distilling waste compost produces a complex of antifungal metabolites active against the phytopathogen pythium aphanidermatum

Adding compost to soil can result in plant disease suppression through the mechanisms of antagonistic action of compost microflora against plant pathogens. The aim of the study was to select effective antagonists of Pythium aphanidermatum from compost, to assess the effect of its extracellular metabolites on the plant pathogen, and to characterize antifungal metabolites. The fungal isolate selected by a confrontation test was identified as Aspergillus piperis A/5 on the basis of morphological features and the internal transcribed spacer (ITS) region, beta-tubulin and calmodulin partial sequences. Liquid chromatography-mass spectroscopy (LC-MS) analysis showed that gluconic and citric acid were the most abundant in the organic culture extract. However, the main antifungal activity was contained in the aqueous phase remaining after the organic solvent extraction. The presence of considerable amounts of proteins in both the crude culture extract as well as the aqueous phase remaining after solvent extraction was confirmed by SDS-PAGE. Isolated Aspergillus piperis A/ 5 exhibits strong antifungal activity against the phytopathogen Pythium aphanidermatum. It secretes a complex mixture of metabolites consisting of small molecules, including gluconic acid, citric acid and itaconic acid derivatives, but the most potent antifungal activity was associated with proteins resistant to heat and organic solvents. Our findings about the activity and characterization of antagonistic strain metabolites contribute to the understanding of the mechanism of interaction of antifungal metabolites as well as fungal-fungal interaction. The obtained results provide a basis for further application development in agriculture and food processing

Aspergillus Piperis A/5 from Plum-Distilling Waste Compost Produces a Complex of Antifungal Metabolites Active Against the Phytopathogen Pythium Aphanidermatum

Adding compost to soil can result in plant disease suppression through the mechanisms of antagonistic action of compost microflora against plant pathogens. The aim of the study was to select effective antagonists of Pythium aphanidermatum from compost, to assess the effect of its extracellular metabolites on the plant pathogen, and to characterize antifungal metabolites. The fungal isolate selected by a confrontation test was identified as Aspergillus piperis A/5 on the basis of morphological features and the internal transcribed spacer (ITS) region, beta-tubulin and calmodulin partial sequences. Liquid chromatography-mass spectroscopy (LC-MS) analysis showed that gluconic and citric acid were the most abundant in the organic culture extract. However, the main antifungal activity was contained in the aqueous phase remaining after the organic solvent extraction. The presence of considerable amounts of proteins in both the crude culture extract as well as the aqueous phase remaining after solvent extraction was confirmed by SDS-PAGE. Isolated Aspergillus piperis A/ 5 exhibits strong antifungal activity against the phytopathogen Pythium aphanidermatum. It secretes a complex mixture of metabolites consisting of small molecules, including gluconic acid, citric acid and itaconic acid derivatives, but the most potent antifungal activity was associated with proteins resistant to heat and organic solvents. Our findings about the activity and characterization of antagonistic strain metabolites contribute to the understanding of the mechanism of interaction of antifungal metabolites as well as fungal-fungal interaction. The obtained results provide a basis for further application development in agriculture and food processing

Statistical interpretation of the results in quality control of milk and milk\u27s products

U članku je na 4 primjera prikazana primjena statističkih metoda u kontroli kakvoće mlijeka i mliječnih proizvoda. Primjeri ilustriraju utvrđivanje sistematske pogreške dviju metoda, provjeru kategorija kakvoće mlijeka na temelju broja živih bakterija i rješavanju spora u postupku "super-analize"