Effect of Casein Hydrolysates on Yogurt Fermentation and Texture Properties during Storage

Abstract

U radu je istražen utjecaj kazeina hidroliziranog papainom na kiselost jogurta i rast probiotskih bakterija tijekom fermentacije. Procijenjen je postotak preživljavanja probiotskih bakterija te tekstura jogurta tijekom skladištenja na 4 °C. Hidrolizati su znatno smanjili vrijeme fermentacije i koagulacije jogurta. Povećanje kiselosti nakon fermentacije je smanjeno dodatkom hidrolizata. Hidrolizati su povećali broj probiotičkih bakterija na početku fermentacije, ali se pred kraj fermentacije smanjio rast probiotičkih organizama. Dodatak hidrolizata povećao je postotak preživljavanja probiotičkih bakterija. Hidrolizati su značajno (p<0,05) povećali adhezivnost jogurta, osim 0,5 % hidrolizata sa stupnjem hidrolize od 8,5 %. Dodatak hidrolizata značajno je poboljšao (p<0,05) senzorska svojstva jogurta nakon skladištenja. Utjecaj hidrolizata kazeina na fermentaciju i teksturu ovisi o njihovoj molekularnoj masi.Effects of casein hydrolysates by papain on acidification of the yogurts and growth of probiotic bacteria during yogurt fermentation have been investigated. The viability of probiotic bacteria and texture characteristics of the yogurts during storage at 4 °C have been evaluated. The hydrolysates strongly decreased the fermentation and coagulation time of the yogurts. The post-fermentation acidification was retarded by the hydrolysates. The hydrolysates increased the probiotic counts during initial fermentation stage. The growth of the probiotic organisms decreased at the final stage. Survival of probiotic bacteria was improved by the hydrolysates. The hydrolysates significantly (p<0.05) increased the adhesiveness of the yogurts except for 0.5 % of hydrolysate with degree of hydrolysis of 8.5 %. The sensory evaluation scores of the yogurts were significantly (p<0.05) improved by the hydrolysates after the storage. The effect of casein hydrolysates on fermentation and texture properties was related to the molecular mass of the hydrolysates