# The Sensory Quality and Volatile Profile of Dark  
Chocolate Enriched with Encapsulated Probiotic  
_Lactobacillus plantarum_ Bacteria  
[PERSON]  
1 Faculty of Agriculture, University of Belgrade, Nemanjina 6, Belgrade 11080, Serbia; 2 [EMAIL_ADDRESS]  
[PERSON]  
2 Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork P61, Ireland; [EMAIL_ADDRESS] (S.S.); 3 [EMAIL_ADDRESS] (K.K. ); [EMAIL_ADDRESS] (D.M.) [PERSON]  
2 Institute for Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444, Belgrade 11000, Serbia; [EMAIL_ADDRESS]  
[PERSON]  
2 Institute for Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444, Belgrade 11000, Serbia; [EMAIL_ADDRESS]  
[PERSON]  
3 Institute for Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444, Belgrade 11000, Serbia; [EMAIL_ADDRESS]. survival rates through gastro-intestinal tract conditions were four times higher in chocolate than in dairy products. Dark chocolate is made from cocoa (in form of paste, powder or butter) and sugar (added as an emulsifier and sometimes as a flavour) and it does not contain milk, while milk chocolate contains whole-milk powder, including emulsifying agents and very often some flavourings [11; 12]. Therefore, dark chocolate with 75% cacao was chosen as a probiotic carrier in this study. The use of a dense food matrix which contains a higher content of protective ingredients has additional advantages over typical dairy probiotic products. Chocolate can be defined as a product made primarily of cocoa solids and cocoa fats, although since 1999 up to 5% of its content can be comprised of vegetable fat alternatives, such as palm oil, shea, sal, illipe or mango kernel butter [11]. Different chocolate flavours can be obtained by varying the temperature and time when roasting the beans or adjusting the quantities of cocoa solids and/or adding non-chocolate ingredients. The specific flavour of dark chocolate is primarily due to a very rich volatile fraction which is composed of a mixture of hundreds of volatile and non-volatile compounds. There are many descriptive studies that have identified more than 600 volatile compounds in chocolate products and cocoa, mainly pyrazines, amines and amides, acids, esters and hydrocarbons [4; 13; 14]. Composition of dark chocolate depends on the genotype of the cocoa bean and the processes used during chocolate production: fermentation, drying, roasting and conching [14]. Cocoa bean fermentation is an essential step in the development of key volatile fractions (alcohols, esters and fatty acids) and the formation of flavour precursors (amino acids and reducing sugars). Molecules generated during cocoa bean fermentation, such as pyrazines, aldehydes (cocoa, nut aroma), esters (fruity aroma) and polyphenols (astringent and bitter taste) are mainly responsible for cocoa and chocolate flavour formation [15; 16]. Important flavour-active compounds produced during fermentation include 2-methylbutanoate, tetramethyl-pyrazine and other pyrazines. Bitter notes are evoked by caffeine and threbromine, while other flavour precursor components derived from amino acids during fermentation include phenyl-acetaldehyde, 3-methylbutanol, 2-methyl-3-(methyldithio)furan, 2-ethyl-3,5-dimethyl-methylpyrazine and 2,3-diethyl-5-methylpyrazine [17]. Flavour development continues during drying (moisture decrease in cocoa bean from around 60% to around 7.5%), where the characteristic brown colour is developed and the levels of acidity and astringency are reduced by decreasing the volatile acids and total polyphenol content. The next crucial step for flavour improvement is cocoa roasting and it involves Maillard reactions (chemical reactions between amino acids and reducing sugars under heat treatment), which provide the desirable flavour and colour formation. Roasting also affects the concentration of polyphenols and their ability to interact with proteins, which causes a decrease in astringency [18; 19].