Sustavni pristup ispitivanju ekonomske isplativosti hidrolize nusprodukata obrade atlantskog lososa (Salmo salar) pomoću endopeptidaza

• Main Authors: Aspevik, Tone, Egede-Nissen, Henning, Oterhals, Åge
• Format: Article in Journal/Newspaper
• Language: English
• Published: Faculty of Food Technology and Biotechnology, University of Zagreb 2016
• Subjects: endopeptidaza; hidrolizat proteina ribe; stupanj hidrolize; pH stat; iskorištenje proteina; ekonomska isplativost; endopeptidase; fish protein hydrolysate; degree of hydrolysis; pH-STAT; protein recovery; cost efficiency; Atlantic salmon; Salmo salar
• Online Access: http://hrcak.srce.hr/169981; http://hrcak.srce.hr/file/250760

U radu je pomoću standardnih metoda u podlozi s kazeinom ispitana i uspoređena hidrolitička aktivnost i ekonomska isplativost primjene pet komercijalnih endopeptidaza (Alcalase 2.4L, Corolase 7089, Neutrase 0.8L, Promod 671L i Protex 7L) u hidrolizi nusprodukata obrade atlantskog lososa. Nakon karakterizacije supstrata provedena je hidroliza pri pH=6,5 i t=50 °C, te su izračunate specifične konstante koje ovise o masenom omjeru dušika i proteina: konverzijski faktor fN=5.23 i ukupna količina peptidnih veza htot=9.3 mmol/g. Svi su enzimi bili jednako učinkoviti u hidrolizi pri malom omjeru enzimske aktivnosti i koncentracije supstrata. Pri najvećem omjeru enzimske aktivnosti i koncentracije supstrata dobivene su veće vrijednosti stupnja hidrolize (DH=14,2-14,6 %) nakon 120 min obrade pomoću endopeptidaza Protex 7L, Alcalase 2.4L i Promod 671L, nego pomoću endopeptidaza Corolase 7089 (13.2 %) i Neutrase 0.8L (11.6 %). Nije opaženo da iskorištenje proteina ovisi o stupnju hidrolize. Nakon toga je izmjerena aktivnost enzima pomoću pH stata, te je određen udjel reaktivnih amino skupina o-ftaldialdehid (OPA) metodom. Na osnovi podataka dobivenih pomoću pH stata izrađeni su regresijski modeli odzivnih površina. Dobiveni su modeli upotrijebljeni za ispitivanje utjecaja vremena hidrolize i omjera enzimske aktivnosti i koncentracije supstrata na stupanj hidrolize i iskorištenje proteina. Modeliranjem i analizom troškova proizvodnje enzima utvrđeno je da je Protex 7L najisplativija endopeptidaza za hidrolizu nusprodukata obrade atlantskog lososa. The hydrolytic and cost efficiencies of five endopeptidases (Alcalase 2.4L, Corolase 7089, Neutrase 0.8L, Promod 671L and Protex 7L) to hydrolyze Atlantic salmon by-products were compared at standardized activity levels based on a casein assay. The substrate was characterized prior to the hydrolytic experiments (pH=6.5, t=50 °C) to obtain substrate-specifi c constants for nitrogen to protein mass (in g) ratio, i.e. conversion factor fN=5.23 and total amount of peptide bonds htot=9.3 mmol per g of protein. At low enzyme activity to substrate ratio, all enzymes were equally effi cient in hydrolyzing the substrate. At highest enzyme activity to substrate ratio, Protex 7L, Alcalase 2.4L and Promod 671L gave higher degree of hydrolysis (DH=14.2–14.6 %) than Corolase 7089 (13.2 %) and Neutrase 0.8L (11.6 %) after 120 min of hydrolysis. No differences were observed in protein recovery (yield of solubilized protein) relative to DH. Determination of DH was followed by the pH-STAT and o-phthaldialdehyde methods. Based on pH-STAT data, response surface regression models were established based on the combined eff ects of hydrolysis time and enzyme activity to substrate ratio on DH and protein recovery. The modelling approach was combined with enzyme cost to identify the most cost-efficient enzyme (Protex 7L).