Effect of sweetener supplement on the viability of Lactobacillusacidophilus La 5, Bifidobacteriumanimalis subsp. lactis Bb 12 and Streptococcus thermophilus St 36 infermented goat milks during storage
This research studied the effect of milk supplementation with inulin, oligosaccharide, polydextrose, fructose and saccharose on the viability of probiotics in fermented goat milk during refrigerated storage (21 days). Sweetener supplements were added to UHT goat milk at the rate of 3.0% while a control sample was also maintained without any added supplements. Control and supplemented milk samples were fermented by a commercial starter culture containing Lactobacillus acidophilus La 5, Bifidobacterium animalis subsp. lactis Bb 12, and Streptococcus thermophilus St 36. Inoculated samples were incubated at 37°C for 8 h and stored at 4°C Estimation of microbial viability was carried out at days 1th, 7th, 14th, and 21th in triplicates from each batch. The results showed that, during the storage period, the viability of probiotic bacteria in fermented goat milk was not notably lower than control milk. In general, inulin and polydextrose added fermented goat milk samples demonstrated higher viable bacteria counts than other supplemented milk samples at the end of storage. All fermented milk samples contained the recommended levels (6-7 Log cfu ml-1) of probiotic bacteria except Bifidobacterium animalis subsp. lactis Bb 12 at the end of the 21-day shelf life.
Innovation and optimization are keywords in applied food research and food industry. In the dairy field, several new brands of fermented foods are introduced in the market every year (1, 2). Among these so called ‘functional foods’, much of the attention was focused on probiotic products. Probiotic foods contain microorganisms or components of microbial cells that have a beneficial effect on the health and well-being of the consumer host (3, 4).
The proportion of goat milk processed into cheeses and yoghurts is higher in comparison to cow milk. It is well-known that goat’s milk has better digestibility in comparison with cow’s milk because of smaller size of the fat globules, more easily hydrolyzed triacylglycerol containing short-chain fatty acids and more essential amino-acids, higher proportion of soluble minerals and smaller size of casein micelles (5, 6). Further, goat milk can be a good substitute for cow milk in situations where bovine milk causes an allergic reaction; furthermore, some consumers may prefer goat milk for dietetic reasons or sensory properties (7). Although goat’s milk is used for therapeutic purposes ...