نسیم خورشیدیان

Non-dairy probiotic beverages such as fruit juices have been popular for all age groups due to their vitamins, minerals, antioxidants and bioactive components with no allergens such as milk proteins and lactose. To exert their health benefits, probiotics should survive during food processing and storage as well as gastrointestinal tract. Incorporation of probiotics into fruit juices is more challenging than that in dairy products because of the low pH. Therefore, encapsulation of probiotics using various hydrocolloids and appropriate methods can protect probiotics from detrimental factors, improving their viability.

In the present study, free and encapsulated Lactiplantibacillus plantarum and Bifidobacterium bifidum were incorporated into apple juice and physicochemical characteristics of the fruit juice (pH, acidity, °Brix and color), viability of the probiotics and sensory evaluation of apple juices were investigated during 60-d storage at 4 °C.

Results showed encapsulation efficiencies of 90.21 and 85.54% for Lactiplantibacillus plantarum and Bifidobacterium bifidum in xanthan-chitosan hydrogels, respectively. Lactiplantibacillus plantarum and Bifidobacterium bifidum populations showed logarithmic decreases of 2.21 and 2.54 in free and 0.93 and 1.02 in encapsulated forms, respectively. However, the two bacteria survived in encapsulated form until the end of storage. In apple juices with free Lactiplantibacillus plantarum and Bifidobacterium bifidum, pH decreased from 3.7 to 3.11 and 3.3, respectively. In encapsulated probiotics, no significant differences were seen in pH of the samples. Moreover, apple juice samples with free probiotics included lower °Brix and higher acidity compared to the samples with encapsulated bacteria. Sensory evaluation of samples revealed that apple juices with encapsulated probiotics received higher scores than that apple juices with free bacteria did. The highest (3.95) and the lowest (2.48) overall acceptability scores after 60 d of storage were observed in samples containing encapsulated Bifidobacterium bifidum and free Lactiplantibacillus plantarum, respectively. It can be induced that use of xanthan-chitosan hydrogels can be used for the efficient encapsulation of probiotics and improve their survival during storage without adverse effects on sensory evaluation.

According to the World Health Organization, viable probiotics could have health effects. However, in recent years, many benefits have been observed through application of inactive and non-viable cells of microbes or their metabolites. Therefore, probiotics could be defined as viable, inactive, or non-viable microbial cells or cell extracts that have beneficial health effects on the host. Based on the proposed terminology, probiotics are divided into three categories: real probiotics, pseudo-probiotics, and ghost probiotics. This article reviewed the beneficial effects and underlying mechanisms of inactive and non-viable microbial cells on the host. Also in this article, new proposed terms are described based on the nature of the cell or active ingredient so that it could cover all aspects of the microbial cell (viable, non-viable, inactive, and cell extract).