The Changes in the Viable Counts of L

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The changes in the viable counts of L. acidophilus, Bifidobacteria, and L. casei in probiotic goat milk yogurts during refrigerated storage are presented in he probiotic cultures were relatively stable in the yogurt and their populations remained above 106 CFU/g up to 8 weeks at 4 ◦C, suggesting that goat milk yogurt may be an excellent carrier for the probiotics. No differences (P > 0.05) in rate of change of population of all the three probiotic cultures were observed between the control and the MTGase-treated samples. When MTGase is used in goat milk yogurt preparation, milk was pretreated for 1 h with enzyme, which was subsequently inactivated before addition of the probiotic yogurt starter. This setup mimics conditions considered to be suitable for MTGase application for industrial yogurt manufacture. However, the enzyme can also be added to milk at the same time as the starter culture. In this case, the enzyme reaction proceeds during fermentation. Neve et al. (2001) have shown that if the enzyme is supplied simultaneously with the yogurt starter bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) without subsequent inactivation, an increased viability of the L. bulgaricus culture was observed during cold storage of the yogurt from bovine milk. Hence, it will be interesting to also study the effect of enzymatic cross-linking of milk proteins without inactivation of enzyme on the probiotic culture survivability, as well as functional properties of probiotic goat milk yogurt. At present, probiotics are increasingly incorporated into fermented dairy products. Because some probiotic strains grow slowly in milk, the usual practice is to add yogurt starter bacteria to enhance the fermentation process for making probiotic yogurt (Samona and Robinson, 1994). Neve et al. (2001) found that pretreatment of bovine milk with MTGase induces a minor imbalance of the yogurt starter bacteria during fermentation, whereas a long-term application of MTGase (without enzyme inactivation) in bovine yogurt results in a stabilizing effect on the viability of L. bulgaricus. Since probiotic goat milk yogurt contains cultures of S. thermophilus and L. bulgaricus, it may be of interest now to study the effect of an MTGase treatment

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The Changes in the Viable Counts of L

Transcript of The Changes in the Viable Counts of L

Page 1: The Changes in the Viable Counts of L

The changes in the viable counts of L. acidophilus, Bifidobacteria, and L. casei in probiotic goat milk yogurts during refrigerated storage are presented in he probiotic cultures were relatively stable in the yogurt and their populations remained above 106 CFU/g up to 8 weeks at 4 ◦C, suggesting that goat milk yogurt may be an excellent carrier for the probiotics. No differences (P > 0.05) in rate of change of population of all the three probiotic cultures were observed between the control and the MTGase-treated samples. When MTGase is used in goat milk yogurt preparation, milk was pretreated for 1 h with enzyme, which was subsequently inactivated before addition of the probiotic yogurt starter. This setup mimics conditions considered to be suitable for MTGase application for industrial yogurt manufacture. However, the enzyme can also be added to milk at the same time as the starter culture. In this case, the enzyme reaction proceeds during fermentation. Neve et al. (2001) have shown that if the enzyme is supplied simultaneously with the yogurt starter bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) without subsequent inactivation, an increased viability of the L. bulgaricus culture was observed during cold storage of the yogurt from bovine milk. Hence, it will be interesting to also study the effect of enzymatic cross-linking of milk proteins without inactivation of enzyme on the probiotic culture survivability, as well as functional properties of probiotic goat milk yogurt. At present, probiotics are increasingly incorporated into fermented dairy products. Because some probiotic strains grow slowly in milk, the usual practice is to add yogurt starter bacteria to enhance the fermentation process for making probiotic yogurt (Samona and Robinson, 1994). Neve et al. (2001) found that pretreatment of bovine milk with MTGase induces a minor imbalance of the yogurt starter bacteria during fermentation, whereas a long-term application of MTGase (without enzyme inactivation) in bovine yogurt results in a stabilizing effect on the viability of L. bulgaricus. Since probiotic goat milk yogurt contains cultures of S. thermophilus and L. bulgaricus, it may be of interest now to study the effect of an MTGase treatment on the growth behavior and viability of these conventional yogurt cultures during the production and storage of probiotic goat milk yogurt products.

Schimbările viabile contează in L. acidophilus, Bifidobacteria și L. casei in iaurt din lapte de capra probiotic în timpul depozitării în condiții de refrigerare sunt prezentate în el culturi probiotice au fost relativ stabile în iaurt și populațiile lor au rămas peste 106 CFU / g până la 8 săptămâni la 4 ◦C, sugerând că iaurt lapte de capră poate fi un operator de transport excelent pentru probiotice. Nu au fost observate diferențe (P> 0,05) în rata de schimbare a populației a tuturor celor trei culturi probiotice între probele MTGase tratați controlul și. când MTGase este utilizat în laptele de capră pentru pregătire iaurtului, laptele a fost pretratat timp de 1 oră cu enzimă, care ulterior a fost inactivata înainte de adăugarea starterului iaurt probiotic. Acest imita configurare condiții considerate a fi adecvate pentru aplicarea MTGase pentru producerea de iaurt industrial. Cu toate acestea, enzima poate fi de asemenea adăugate la lapte în același timp cu cultura inițială.

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In acest caz, reacția enzimatică are loc în timpul fermentării. Neve et al. (2001) au arătat că, dacă enzima este livrat simultan cu bacterii iaurt starter (Streptococcus thermophilus și Lactobacillus delbrueckii subsp. Bulgaricus) fără inactivarea ulterioară, a fost observată o creștere a viabilității culturii L. bulgaricus timpul depozitării la rece a iaurtului la bovine lapte. Astfel, acesta va fi interesant de studiat, de asemenea, efectul de enzimatice reticularea proteinelor din lapte fără inactivarea enzimei pe supraviețuire cultura probiotică, precum proprietățile funcționale ale iaurtului probiotic din lapte de capră. În prezent, probioticele sunt din ce în ce încorporate în produse lactate fermentate. Deoarece unele tulpini probiotice cresc lent în lapte, practica obișnuită este de a adăuga bacterii iaurt starter pentru a îmbunătăți procesul de fermentație pentru a face iaurt probiotic (Samona și Robinson, 1994). Neve et al. (2001) au descoperit că pretratamentul de lapte de vacă cu MTGase induce un dezechilibru minor al bacteriilor iaurt starter timpul fermentației, în timp ce o aplicație pe termen lung a MTGase (fără inactivarea enzimei) în rezultatele iaurt bovine într-un efect stabilizator asupra viabilității L. bulgaricus. Deoarece laptele de capră probiotic iaurt conține culturi de S. thermophilus și L. bulgaricus, ar putea fi de interes acum pentru a studia efectul unui tratament MTGase pe comportamentul creșterii și viabilității acestor culturi iaurt convenționale timpul producerii și stocării de lapte de capră probiotice in produse iaurt.