FORMULATION AND EVALUATION OF LOW-CALORIE ICE CREAM CONTAINING {LACTOBACILLUS ACIDOPHILUS} PROBIOTIC MICROSPHERES AND GLUCOMANNAN FIBER

• Main Author: Angelina, Joanne
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/78933
• Institution: Institut Teknologi Bandung

Probiotic L. acidophilus has health benefits if it is available in a sufficient amount at the target site on the intestine. Microsphere has been applied to maintain the viability of probiotics. This delivery system can be made using materials that have mucoadhesive strength, to prolong probiotics contact on the target tissue. In this research, probiotic microspheres were incorporated into ice cream. L. acidophilus were characterized and cultivated on its stationer phase. Probiotics were encapsulated to become microspheres through emulsification method using soybean oil as oil phase, sodium alginate and guar gum solution as water phase, as well as calcium cloride ano chitosan solution as crosslinking agent. Microspheres were made with different component solution concentration to be optimized. They were evaluated 'for its mucoadhesive property using falling liquid film method in rat's intestine. Its viability after 2 hours incubation in simulated gastric juice (SGJ) and after 4 hours incubation in simulated intestinal juice (SIJ) was evaluated using total plate count (TPC) method. Low calorie ice cream was optimized by varying soybean oil and sucrose content, as well as with addition of fat replacer and sugar substitutes in the formulation. Those ice cream products were characterized based on its pH, viscosity, overrun, total solid content, and melting ability. Ice cream was also evaluated on its total microbe contamination, freeze-thaw test, sensory evaluation, and total nutrition analysis. The optimized formula was used as L. acidophilus microspheres' carrier. Its viability through 90-day storage condition in -200C temperature was also evaluated using TPC method. Optimum microsphere was obtained from formula of 3% sodium alginate, 1% guar gum, 1% chitosan, 2.78% CaC12, and 0.75% lechitine in soy oil. Mucoadhesive study showed that this optimum microsphere has intestinal adhesivity of Addition of chitosan in alginate microsphere formulation could improve its muccadhesive strength on intestinal mucosa. With this mucoadhesive strength, this microsphere formula has potential to adhere and colonize in intestinal mucosa. After incubation in simulated gastric juice (SGJ) and simulated intestinal juice (SIJ), L. acidophilus in optimized microsphere formula left of 1.92x107 CFU/g viable cells, from the origin of 2.45x108 CFU/g, while nude L. acidophillus left of 7.15x103 CFU/g viable cells, fgom the origin of 4.41x108 CFU/g viable cells. Optimized ice cream formula contained 73.05% soy milk, 20% polydextrose, 5% whey protein isolate, 0.20% gelatine, 0.25% glucomannan, 4% sucrose, 0.1% stevia sugar, 2% chocolate powder, and 1% vanilla paste. Prebiotic properties of soy milk and polydextrose in ice cream can help maintain probiotic's viability. Polydextrose, which has an energy value of only 1 kkal/g, can be used as fat replacer, together with whey protein isolate. Stevia sugar was used as sugar substitute. Glucomannan fiber, as stabilizer, has a good water binding capacity, therefore might be useful to prevent crystal growth and gives good textures to the ice cream. This optimum ice cream can be classified as low-calorie ice cream, with total calories of 96.86 kcal/100g. After 90 days, microspheres with optimum formula, that have been incorporatedrinto this ice cream formula, left of 3.71x107CFU/g viable cells, from the origin of 6.50x108 CFU/g cells, while probiotic product contained nude L. acidophillus left of 2.97x105 CFU/g viable bacteria from the origin of 8.70x10 8 CFU/g. Viability study of L. acidophilus in SGJ and SIJ, and in optimum ice cream formula, indicated that the amount of natrium alginate and chitosan difference in this experimental design, did not give any significant difference (p>0.05) on the viability of probiotics in gastrc pH and intestinal pH, as well as in low-calorie ice cream matrix. However, those 6 formulas gives better viability compared with nude L. acidophilus, significantly (p<0.05). Therefore, it can be concluded that optimum formula of L. acidophilus microsphere could maintain probiotic's viability in gastric pH and intestinal pH. Innoculated of L acidophilus microsphere into ice cream could improve the viability during storage. It is because of the microspheres that protected probiotic from the direct contact of gastrointestinal pH and sugar contained in ice cream, from mechanical distruption in freezing process, as well as from crystal growth during storage.