Incorporation of Bifidobacterium animalis subspecies lactis bb-12® and Akkermansia muciniphila in chocolate matrices

Abstract

Currently, consumers are seeking healthier food options, prioritizing goods with improved organoleptic and health properties. Consequently, the food industry has been focusing on developing functional foods, which are characterized by the incorporation of bioactive ingredients, which complement essential nutrition (food supplement) or have a pharmacological activity (nutraceutical). Probiotics, defined as "live microorganisms that, when administered in adequate amounts, confer benefits to human health", are a good example. These have been incorporated into different types of food matrices, particularly dairy matrices, and more recently into cereal or fruit and vegetable matrices. In an attempt to increase the portfolio of attractive food vectors for the delivery of probiotic bacteria to the consumer, chocolate was selected and studied due to its extreme popularity among consumers. Thus, the main objective of this thesis was to study the incorporation of two probiotic strains, namely Bifidobacterium animalis subsp. lactis BB-12® (classical probiotic strain) and Akkermansia muciniphila DSM 22959 (candidate strain for new probiotic generation) in three chocolate matrices with different cocoa percentages (33. 6%; 54.5% and 70.5%) and evaluate their viability and stability over 28 days of aerobic storage and in simulated gastrointestinal tract (GIT) passage. Simultaneously, the content of total phenolic compounds was quantified, and the following biological activities were determined: antioxidant, antidiabetic, and antihypertensive. For the probiotic B. animalis BB-12®, the most suitable matrix was the chocolate containing 70.5% cocoa content, as it assured cell concentration levels of 108 CFU/g after 28 days of aerobic storage and presented viable cell numbers of 107 CFU/g during in vitro GIT simulation. Furthermore, the chocolates with 70.5% cocoa presented greater total phenolic compounds content and higher bioactivities (antioxidant, antidiabetic and antihypertensive). Regarding A. muciniphila DSM 22959, the most appropriate chocolate matrix was the one with 54.5% cocoa content, as cell viability was kept at 106 CFU/g, after 28-day aerobic storage. Though, A. muciniphila survived during aerobic storage in the chocolate matrix, this bacterium was unable to endure the simulated GIT conditions, when incorporated into chocolate. Regarding parameters such as overall quality aspect and texture, results indicated that the addition of probiotics modifies the chocolate’s surface and increases its hardness. Moreover, the results of a performed sensory analysis test (triangular test) with 70.5% cocoa content chocolate incorporated with A. muciniphila demonstrated that more than 50% of the testers could not distinguish between a plain chocolate (control) and a probiotic-incorporated chocolate. Although the addition of probiotics leads to changes in the organoleptic properties of the chocolate matrix, the supplementary benefits of a probiotic chocolate overweigh these differences, being therefore more attractive to the consumer. In conclusion, a chocolate matrix with high cocoa content (dark chocolate) is a suitable carrier for Bifidobacterium animalis subsp. lactis BB-12® and Akkermansia muciniphila.

Date of Award	12 Jan 2023
Original language	English
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Daniela Machado (Supervisor), Joana Cristina Barbosa (Co-Supervisor) & Ana Maria Gomes (Co-Supervisor)