| Abstract | Cilj ovog rada bio je odrediti utjecaj vremena tretmana, amplitude i frekvencije primijenjenog ultrazvuka visokog intenziteta na kvalitetu i stabilnost minimalno obrađenog krumpira tijekom 8 dana skladištenja. Krumpir je oguljen i narezan na ploške, tretiran ultrazvukom u 2 % otopini natrijeva askorbata te vakumiran i skladišten na 4 °C. Ploške krumpira su tretirane ultrazvukom frekvencije 37 i 80 kHz, amplitudama od 30 %, 70 % i 100 %, tijekom 15, 30 45 i 60 minuta. Tijekom vremena skladištenja od 8 dana pratili su se fizikalno kemijski parametri (ukupna suha tvar, pH), boja, tekstura i senzorska svojstva ploški. Veći utjecaj na sprječavanje enzimskog posmeđivanja utvrđen je primjenom frekvencije od 37 kHz i ona je izabrana za nastavak istraživanja. Na ukupnu suhu tvar najveći utjecaj je imalo vrijeme skladištenja i toplinska obrada. Tretmanom ultrazvukom pri amplitudi od 70 % i vremenu od 30 minuta postignuta je stabilnost pH koja u protivnom opada kroz period skladištenja. Za održavanje kvalitete MPK najpogodniji se pokazao tretman ultrazvukom frekvencije od 37 kHz amplitude 70 % uz vrijeme tretmana od 15 minuta jer je pri tom tretmanu ostvareno najbolje očuvanje senzorskih svojstava, boje, kolorimetrijski s najvišom L* vrijednosti, i teksture ploški koja je ostala gotovo nepromijenjena, uz povećanje kremoznosti. |
| Abstract (english) | The aim of this study was to evaluate influence of the treatment time, amplitude and frequency of high intensity ultrasound on the quality and stability of minimally processed potatoes during 8 days of storage. The potatoes were peeled and sliced, sonicated in 2% sodium ascorbate solution, vacuumed and stored at 4 °C. The potato slices were treated with ultrasound at frequencies of 37 and 80 kHz, amplitudes of 30%, 70%, and 100%, for 15, 30, 45, and 60 minutes. Physicochemical parameters (total dry matter, pH), color, texture, and sensory properties of slices were evaluated during 8-days of storage. The most significant influence on the prevention of enzymatic browning had the frequency of 37 kHz and it was chosen to continue the research. Storage time and heat treatment had the greatest impact on total dry matter. Ultrasound treatment at an amplitude of 70% and a time of 30 minutes achieved pH stability which otherwise decreases during the storage period. Ultrasound treatment with a frequency of 37 kHz amplitude of 70% treatment time of 15 minutes proved to be the most suitable for maintaining the quality of MPK, because the best color preservation was achieved during this treatment, colorimetrically with the highest L * value, sensory evaluation, MPK texture remained almost unchanged, with increasing creaminess. |
