An innovative approach: Cow/oat milk based kefir

Abstract

The aim of this study was to evaluate the potential of kefir production using cow-oat milk mixture. Therefore kefir samples with 20, 40 and 60 % of oat milk were produced. The effect of oat-milk ratio on physicochemical, rheological, microbiological and sensory characteristics of the kefir samples was studied during 21 days storage at refrigerated conditions. Increasing oat milk concentration affected the whey-off and apparent viscosity by higher whey off and lower viscosity results. Also the proteolytic activity of the samples was decreased by raising the oat milk concentrations. Increase of the oat milk concentration leaded to a decrease of pH of the samples. Statistical analysis showed that the lactococci and lactobacilli viable cell counts differed among the samples while the highest count was detected in sample with the highest amount of oat milk. The control sample (without oat milk) had higher yeast count during the storage period. The final product with 20 % of oat-milk and without addition of flavour was found to be the most acceptable by the sensory panellists. The results indicate the possibility for a new cow/oat milk based kefir.Cilj ovog istraživanja bio je utvrditi mogućnost proizvodnje kefira iz mješavine kravljeg i zobenog mlijeka. Stoga su proizvedeni uzorci kefira s 20, 40 i 60 % zobenog mlijeka. Tijekom 21 dana skladištenja na hladnom ispitivan je utjecaj različitih omjera zobenog i kravljeg mlijeka na fizikalna, reološka, mikrobiološka i senzorska svojstva proizvedenih uzoraka kefira. Povećanje udjela zobenog mlijeka uzrokovalo je povećanje sinereze, smanjenje prividne viskoznosti te smanjenje proteolitičke aktivnosti u uzorcima kefira. Osim toga, povećanje udjela zobenog mlijeka rezultiralo je snižavanjem pH vrijednosti u uzrocima kefira. Statistička analiza pokazala je da se proizvedeni uzorci razlikuju u broju živih stanica laktokoka i laktobacila, s tim da je najveći broj utvrđen u uzroku s najvećim udjelom zobenog mlijeka. Kontrolni uzorak (bez zobenog mlijeka) sadržavao je povećan broj plijesni tijekom cijelog razdoblja čuvanja. Krajnji proizvod s udjelom od 20 % zobenog mlijeka i bez dodatka aroma pokazao se najprihvatljivijim prilikom senzorske ocjene od strane panela. Dobiveni rezultati mogu poslužiti u daljnjem razvoju proizvodnje kefira na bazi mješavine kravljeg i zobenog mlijeka.