Effect of encapsulant matrix on stability of microencapsulated probiotics

Spray dried microencapsulated formulations [25% protein:25% sugar:25% resistant starch (RS):20% oil:5% Lactobacillus rhamnosus GG (LGG)] were compared with commercial freeze dried LGG during non-refrigerated storage with or without packaging. Microencapsulated spray dried LGG was more stable on storage at 25 °C (32, 57 or 70% relative humidity) than freeze dried LGG. The viability of microencapsulated formulations was greater in formulations containing dried glucose syrup compared with glucose, but the type of protein (whey protein isolate or hydrolysed whey protein) has less of an effect. Viability was correlated to the properties of water in the formulations. After long term storage (12 months, 25 °C) in moisture barrier bags, viability was >107 CFU/g for FD LGG and microencapsulated formulations without glucose. Only the microencapsulated formulations were free-flowing and maintained an acceptable colour. There are benefits of microencapsulation for long term packaged non-refrigerated storage and short term storage in open environments.