The effects of different levels of beta-glucan on yoghurt manufactured with Lactobacillus plantarum strains as adjunct culture

This study investigated the effects of beta-glucan on regular (full-fat) yoghurts manufactured with probiotic Lactobacillus plantarum strains (AB6-25, AC18-82 and AK4-11) combination as adjunct culture. In the present work, production was carried out using full fat milk. Four different experimental yoghurts were produced with 0.25, 0.5, 1.0 and 1.5% beta-glucan for treatment groups. All experimental yoghurts were also included probiotic combination and commercial starter yoghurt cultures. In addition, experimental yoghurt groups were compared with three control yoghurts produced with commercial culture (C1), commercial culture and probiotic combination (C2), and commercial culture, Lactobacillus acidophilus LMG 11472 and inulin (C3). Viability of lactic acid bacteria (LAB) and probiotic bacteria, physicochemical attributes of yoghurts, production of aroma compounds and organic acids during the storage period of 21 days at 4 C were determined. The addition of beta-glucan (0.5 and 1%) enhanced the growth of L. plantarum strains (p<0.05) in yoghurt at the end of storage period. It was determined that the addition of beta-glucan had no observable effect on pH, fat and protein content in yoghurt. In general, yoghurts with beta-glucan showed more (p<0.05) syneresis compared to other groups. However, this effect was not observed in yoghurts produced with 0.25% beta-glucan. Concerning aroma compounds of yoghurt, beta-glucan suppressed acetaldehyde formation. With regard to organic acids, the higher beta-glucan addition slightly decreased formic and lactic acid formation. It was concluded that the addition of beta-glucan (0.25-0.5%) with probiotics enhanced microbiological and physicochemical properties of symbiotic yoghurts which may help to improve the health benefits of consumers.