Development of lactose-free products enriched with probiotics and calcium

Abstract

In the modern world, lactose intolerance has become an increasingly significant public health issue. According to the World Health Organization (WHO), more than 65% of the adult population worldwide suffer from various forms of lactose intolerance. As a result, millions of people are forced to exclude dairy products from their daily diet, leading to a significant deficiency of calcium, vitamin D, and probiotics - components that are critically important for maintaining bone health, as well as immune and digestive system function. Lactose intolerance is also highly prevalent in Kazakhstan, affecting approximately 75% of the population. This highlights the urgent need for accessible and comprehensive lactose-free alternatives to traditional food products. In this study, classical microbiological methods, an enzymatic lactose hydrolysis method, modern approaches to functional food development, organoleptic evaluation methods, questionnaire surveys, and statistical analysis were applied. During the study, six isolates of lactic acid bacteria were isolated from fermented food products. The isolates were identified as Lactobacillus plantarum, Lactobacillus reuteri, Lactobacillus casei, and Lactococcus lactis. Lactobacillus reuteri 2 demonstrated a high level of antagonistic activity against the test cultures: Candida albicans (42±2.1 mm), Staphylococcus aureus (41±1.2 mm), Pseudomonas aeruginosa (16±1.2 mm), and Escherichia coli (40±2.3 mm). Lactose-free milk was obtained by enzymatic hydrolysis using β-galactosidase. The residual lactose content was less than 0.01-0.1% (1-10 mg/mL). Calcium gluconate was selected as the optimal form of calcium for yogurt fortification. The calcium content ranged from 120 to 150 mg per 100 g of product, which meets the recommended dietary intake. A yogurt formulation based on lactose-free and soy milk with the addition of probiotics, calcium, and vitamin D was developed. The resulting product is functional and can serve as an alternative to traditional dairy products. Organoleptic evaluation demonstrated that the yogurt has a pleasant taste, uniform texture, and maintains stability during storage. The concentration of the probiotic Lactobacillus reuteri 2 remained at 10⁷–10⁸ CFU/g throughout the storage period. The obtained results confirm the feasibility of industrial production of lactose-free functional yogurt enriched with calcium and probiotics.