Impact of Artichoke Puree in Frozen Yoghurt with Encapsulated and Free Lactic Acid Bacteria

STREPTOCOCCUS thermophilus CH-1, Lactobacillus delbrueckii subsp. bulgaricus Lb-12DRI-VAC and Lactobacillus rhamonsus B- 445 encapsulated or free were successfully used with artichoke puree in ratios 5, 10 and 15 % to formulate frozen yoghurt mixtures. Chemical composition, inulin, antioxidant activity 1, 1-diphenyl-2-picrylhydrazyl (DPPH), pH values, melting rate, viscosity, sensory evaluation were determined and counts of Lb. bulgaricus, S. thermophilus and Lb. rhamnosus were detected when fresh and during storage up to 90 days. Inulin content exhibited different values for the different treatments. The data showed that treatments with added artichoke puree of encapsulated cells had DPPH content higher than that of free cells including the control. Encapsulated treatments exhibited lower pH values than that of free cells. The Control treatment of encapsulated bacteria had higher pH than other encapsulated treatments. The same trends were found in all treatments of free cells. The more increase in added artichoke puree ratio, the more decreased in the melting rate either in encapsulated or in free cells treatments. Treatments of encapsulated cells exhibited melting rate lower than that of free cells at the same ratios including the control. Treatments of free cells had lower viscosity than that of encapsulated cells at the same ratios of the added artichoke puree including controls. This decrease in viscosity values may be attributed to the fact that, the product with lower acidity will have lower viscosity values. For the sensory evaluation, encapsulated samples had better preference than that of free samples. Encapsulated samples have pleasant milky-slight sour taste with natural yoghurt flavor. Inulin caused improvement in flavor, texture and total acceptability. The encapsulated cells sample of 10 % artichoke puree has the most preference evaluation among all treatments even at the end of storage.