Effect of Lactobacillus plantarum Fermentation on the Surface and Functional Properties of Pea Protein-Enriched Flour

Istražen je utjecaj fermentacije s pomoću Lactobacillus plantarum na funkcionalna i fizikalno-kemijska svojstva brašna graška obogaćenog proteinima. Tijekom fermentacije povećavao se stupanj hidrolize do maksimuma od 13,5 % nakon 11 h. Prije mjerenja površinske hidrofobnosti i naboja te ispitivanja funkcionalnih svojstava podešena je pH-vrijednost fermentiranog brašna na pH=4 ili 7. Pri pH=4 površinski naboj, mjeren pomoću zeta potencijala, povećao se s +14 na +27 mV nakon 1 h fermentacije, a zatim smanjio na +10 mV nakon 11 h, dok se pri pH=7 naboj postepeno povećavao s -37 na -27 mV tijekom fermentacije. Površinska hidrofobnost znatno se smanjila tijekom fermentacije pri pH=4, dok se pri pH=7 neznatno smanjila. Kapacitet pijenjenja bio je najveći u emulziji brašna fermentiranog tijekom 5 h pri pH=4, dok je stabilnost pjene bila niska pri obje pH-vrijednosti u svim uzorcima. Emulgirajuća svojstva naglo su se smanjila nakon 5 h fermentacije pri pH=4, a stabilnost emulzija poboljšala se nakon 5 h fermentacije pri pH=7, u usporedbi s kontrolom. Sposobnost vezivanja ulja povećala se s 1,8 g/g pri 0 h na 3,5 g/g nakon 11 h fermentacije, a vode smanjila nakon 5 h, te zatim povećala nakon 9 h fermentacije. Rezultati pokazuju da se fermentacijom brašna graška obogaćenog proteinima mogu mijenjati njegova svojstva te na taj način proizvesti novi funkcionalni sastojci.The effect of Lactobacillus plantarum fermentation on the functional and physicochemical properties of pea protein-enriched flour (PPF) was investigated. Over the course of the fermentation the extent of hydrolysis increased continuously until reaching a maximum degree of hydrolysis of 13.5 % after 11 h. The resulting fermented flour was then adjusted to either pH=4 or 7 prior to measuring the surface and functional attributes as a function of fermentation time. At pH=4 surface charge, as measured by zeta potential, initially increased from +14 to +27 mV after 1 h of fermentation, and then decreased to +10 mV after 11 h; whereas at pH=7 the charge gradually increased from –37 to –27 mV over the entire fermentation time. Surface hydrophobicity significantly increased at pH=4 as a function of fermentation time, whereas at pH=7 fermentation induced only a slight decrease in PPF surface hydrophobicity. Foam capacity was highest at pH=4 using PPF fermented for 5 h whereas foam stability was low at both pH values for all samples. Emulsifying activity sharply decreased after 5 h of fermentation at pH=4. Emulsion stability improved at pH=7 after 5 h of fermentation as compared to the control. Oil-holding capacity improved from 1.8 g/g at time 0 to 3.5 g/g by the end of 11 h of fermentation, whereas water hydration capacity decreased after 5 h, then increased after 9 h of fermentation. These results indicate that the fermentation of PPF can modify its properties, which can lead towards its utilization as a functional food ingredient