Dairy products, particularly fermented products, have risen in popularity in recent decades due to their health-promoting properties, leading to their classification as nutraceuticals, functional foods, or designer foods . As a result, new versions are being developed to fulfill consumer needs. These items contain a single or many bacterial species contributing to the products' favorable properties [2, 3]. Probiotic bacteria are used to make various fermented milk . Different probiotic bacteria like the genera of Lactobacillus and Bifidobacterium have been used to make other fermented dairy products. These microbes have various health benefits, including maintaining the gastrointestinal tract's balance . Prebiotics has been successfully introduced into several lactose-containing dairy products such as Greek yogurt , whey beverage , yogurt , mousse , and fermented milk to boost the action of probiotics and increase fiber consumption . Probiotics have got much interest for their nutritional and functional features, and various research has been conducted to figure out how they work in the human body . As a result, several health organizations recommend a daily dose of viable probiotic cells per serving portion (109 CFU/day). Probiotic cultures have been added to frozen desserts to expand the variety of probiotic foods available on the market .
All over the world, about 66–70% of adults have lactose malabsorption, which means they cannot break down lactose . When lactose-containing foods are consumed, intestinal digestion and colonic fermentation are affected, which can cause diarrhea and other health problems. On the market are lactose-free products made from hydrolyzed or alternative milk sources that lack nutritional and sensory value . Compared to lactose-containing products, these products will cost you more money. As a result, there is much demand for lactose-free products that are nutritious, cost-effective, and well-liked by people . Dairy desserts are popular among many consumers, including kids and the elderly , primarily due to their appealing nutritional and sensory characteristics [16, 17].
The changes to acidophilus milk composition serve various purposes, including improving nutritional value, enhancing probiotic survival during storage, stimulating acidification by probiotics, and improving sensory properties without incurring high costs to meet consumers' growing needs and health expectations [18–20]. Today, the focus is more on how food can keep people healthy and well-being and avoid certain diseases than on how it can satisfy their hunger or give them nutrition. Products with health claims, like probiotic foods, are being made because people are more concerned about their health because of scientific knowledge about how diet and health work together. To promote excellent health and illness prevention, a wide array of tastes, additives, and probiotic cultures that enhance the flavor and texture of the food are incorporated . However, numerous obstacles exist to producing high-quality probiotic products, including the accumulation of acids, oxygen, and peroxide levels and unanticipated culture interactions . As a result, it is preferable to fortify it with various chemicals if necessary to combat such an unpleasant flavor .
Based on the background mentioned above, this research aimed to provide a very initial approach to formulate probiotic acidophilus milk using pre-hydrolyzed milk using β-galactosidase, investigating the fortification effect of cocoa powder to develop probiotic acidophilus milk, and evaluating the lactose-free probiotic acidophilus milk through physicochemical, microbiological and sensory analysis.