Effect of Inoculation Level of Lactobacillus rhamnosus and Yogurt Cultures on Conjugated Linoleic Acid Content and Quality Attributes of Fermented Milk Products

Abstract

The effect of inoculation concentration of Lactobacillus rhamnosus and yogurt cultures and storage time on conjugated linoleic acid (CLA) content and quality attributes of fermented milk products was determined. Yogurt culture (Lactobacillus bulgaricus and Streptococcus thermophilus, 1:1 ratio, YC), L. rhamnosus (LB), and LB co‐cultured with yogurt culture, were inoculated at 106, 107, 108 CFU/mL into a milk with hydrolyzed soy oil as the lipid source. CLA content, microbial counts, acidity, texture, and volatile flavor profile of the fermented milk products were stable during storage at 4 °C for 14 d. Total CLA contents ranged from 0.51 to 1.00 mg CLA/g lipid following 14 d of storage. Inoculation level of L. rhamnosus and yogurt cultures had no significant effect on CLA content and texture, but affected acidity and the volatile flavor profile of the fermented milk products. The fermented milk products produced by L. rhamnosus co‐cultured with yogurt culture with 107 CFU/mL total inoculation level resulted in a high CLA content and desirable quality characteristics. This research demonstrated that the optimal inoculation concentration and the combination of L. rhamnosus and yogurt cultures were important factors to produce fermented milk products with CLA content and acceptable quality attributes.

Effects of probiotic bacteria and oils on fatty acid profiles of cultured cream

“…Production of cream samples using hazelnut oil with YC, and using soybean oil and sunflower oil with LBYC, significantly increased the CLA content. Other studies agreed with the results of this study: Use of probiotic bacteria did not cause a significant increase in CLA content [33,34,36]. Xu et al [34] worked on the determination of CLA in fermented dairy products produced with four probiotic bacteria, Lactobacillus rhamnosus, P. freudenreichii subsp.…”

“…There are many studies about the beneficial effects of functional dairy foods with probiotic and prebiotic, cholesterollowering and anticancerogenic properties [23,[32][33][34][35][36][37]. Improvement of functional properties of yogurt and other fermented milks was extensively studied.…”

Quantification of lipolysis and lipid oxidation during cold storage of yogurts produced from milk treated by ultra-high pressure homogenization

“…In addition, some authors (Lin and Yen, 1999a;Lin and Yen, 1999b;Saide and Gilliland, 2005) have demonstrated MDA-scavenging abilities or even inhibition of linoleic acid peroxidation by starter cultures, although these antioxidant activities originated from cellular lysis and release of intracellular metabolites. However, in some cases such as iron-fortified yogurt (Hekmat and McMahon, 1997) or yogurt from unsaturated fatty acids-enriched milkbase (Barrantes et al, 1996;Boylston and Beitz, 2002;Let et al, 2007;Xu et al, 2006), lipid oxidation products have been detected in greater amounts.…”

Aroma Stability of Fermented Soymilk During Cold Storage

“…2 i 3). Diacetyl współtworzy delikatny aromat jogurtu, jego duża zawartość może powodować słodkawy smak produktu, natomiast nadprodukcja wywołuje niepożądane zmiany [22]. Ze względu na nietrwałość diacetylu, gotowy produkt należy przechowywać w niskiej temperaturze, która hamuje aktywność reduktazy acetoiny.…”