| Abstract | U ovom radu ispitan je utjecaj biološke obrade (provedena u uvjetima fermentacije na čvrstim nosačima) tropa
grožđa, pomoću gljive bijelog truljenja Trametes versicolor,na ekstrakciju fenolnih spojeva (ukupni fenoli UFS,
ukupni flavonoidi UF, prantocijanidini UPA, antocijanini AN) te na antioksidacijsku aktivnost (AA) ekstrakata
tropa grožđa. U ekstraktima tropa grožđa određen je i udio proteina, glukoze te udio pojedinačnih šećera.
Istraživanje je provedeno u dva dijela koja se međusobno razlikuju prema načinu inokulacije T. versicolor na
supstrat i dužini provođenja biološke obrade.
Nakon biološke obrade polovica mase biološki obrađenog tropa grožđa je odmah podvrgnuta ekstrakciji (uvjeti
ekstrakcije: 50% otopina etanola/80 °C/120 min/200rpm), dok je druga polovica sušena (24 h/45 °C) te
ekstrahirana pod istim uvjetima. Šećeri su određeni u vodenim ekstraktima tropa grožđa (uvjeti ekstrakcije:
27 °C/30 min/150 rpm)
Udio fenolnih tvari i glukoze kao i antioksidacijska aktivnost određena je spektrofotometrijskim metodama, dok
su pojedinačni šećeri (glukoza, fruktoza, saharoza) u ekstraktu određeni HPLC metodom.
U prvom dijelu istraživanja biološka obrada kod ekstrakata vlažnog tropa grožđa utjecala je na smanjenje udjela
ekstrahiranih UFS do 68,2%, UPA do 93,1% i UF do 76,7% te na smanjenje AA ekstrakata do 79,1%, u odnosu
na biološki neobrađeni trop grožđa (UFS - 28,5 mgGAE/gst, UPA - 16,8 mg/gst, UF – 26,4 mgCE/gst,
AA - 0,2 ginhDPPH/gst), dok je kod ekstrakata suhog tropa grožđa smanjenje udjela ekstrahiranih UFS do 80,3 %,
UPA do 89,7 % i UF do 89,5 % te na smanjenje AA ekstrakata do 89,9%, u odnosu na biološki neobrađeni trop
grožđa (UFS - 41,2 mgGAE/gst, UPA – 10,0 mg/gst, UF – 30,0 mgCE/gst, AA - 0,2 ginhDPPH/gst). U drugom dijelu
istraživanja dobiveno je smanjenje ekstrairanih UPA do 46,4% i UF do 40,0% te na smanjenje AA ekstrakata do
38,6%, u odnosu na biološki neobrađeni trop grožđa (UPA – 12,7 mg/gst, UF – 30,4 mgCE/gst,
AA - 0,2 ginhDPPH/gst) u ekstraktima vlažnog tropa grožđa, a u suhom je dobiveno smanjenje ekstrahiranih UFS do
35,9%, UPA do 31,0% i UF do 43,4% te na smanjenje AA ekstrakata do 29,1%, u odnosu na biološki neobrađeni
trop grožđa (UFS – 50,9mgGAE/gst, UPA – 10,1 mg/gst, UF – 31,5 mgCE/gst, AA - 0,2 ginhDPPH/gst). |
| Abstract (english) | The aim of this work was to investigate the influence of biological pretreatment (conditons of solid-state fermentation) of grape pomace with white-rot fungi Trametes versicolor on the extractability of phenolic compounds (total phenols TPC, total flavonoids TF, proanthocyanidins TP, anthocyanins AN). Antioxidant activity (AA) is also monitored during the process of fermentation. In grape pomace exstracts proportion of proteins, glucose and share of individual sugars are determined too.
There is two segments of research differ one from the other in way of the inoculation on substratum and in duration of the fermentation procces.
After bilogical pretreatment half of grape pomace is separated for extraction (extraction conditions: 50% ethanol/80°C/120 min/200rpm), while other half is placed on drying (24h/45°C) and then is subjected to extraction under same conditions. Sugars are determined from water exstracts (extraction conditions: 27°C/30 min/150rpm). Proportion of phenolic compounds, glucose and the antioxidant activity is determined by spectrophotometric methods, while individual sugars (glucose, fructose and saccharose) are set by HPLC method. In first part of research biological pretreatment with T. versicolor have an impact on reduction of TPC up to 68,2%, TP up to 93,1% , TF up to 76,7% and AA of extracts were reduced up to 79,1%, compared with rough grape pomace samples (TPC - 28,5 mgGAE/gst, TP - 16,8 mg/gst, TF – 26,4 mgCE/gst, AA - 0,2 ginhDPPH/gst), while reducing in dried samples were up to 80,3% for TPC, up to 89,7% for TP, up to 89,5% for UF, AA of extracts were reduced up to
89,9%, compared with initial samples (TPC - 41,2 mgGAE/gst, TP– 10,0 mg/gst, TF– 30,0 mgCE/gst, AA - 0,2 ginhDPPH/gst).
Decrease of phenolic compounds were also observed in second part of research, up to 46,4% for TP, up to 40,0% for TF and AA of extracts were diminished up to 38,6% in wet grape pomace extracts, compared with initial samples (TP – 12,7 mg/gst, TF – 30,4 mgCE/gst, AA - 0,2 ginhDPPH/gst), while decreasing in dried samples were up to 35,9% for
TPC, up to 31,0% for UP, up to 43,4% for TF and AA of extracts were reduced up to 29,1%, compared with ini tial samples of grape pomace (TFC – 50,9mgGAE/gst, TP – 10,1 mg/gst, TF – 31,5 mgCE/gst, AA - 0,2 ginhDPPH/gst). |
