Sensory, antioxidant and rheological properties of different types of chocolates with probiotics

Abstract

Food products containing beneficial microorganisms, mostly lactic acid bacteria which effectively affect human health, represent one of the largest market of functional foods, with dairy products as the most accessible ones. Tendency that useful probiotic bacteria safer and easier survive the conditions of the gastrointestinal tract, and the need to make them available over a longer period of time compared to durability of dairy products, imposed the idea to conduct the extensive testing of probiotics in chocolate as a carrier. Research program in the scope of this dissertation was aimed at investigating the possibility of application of probiotics in different types of chocolate, because of their sensitivity to a large number of process factors and environmental conditions, and bearing in mind that sustainability is an essential property that determines their effectiveness. By including of probiotic cultures in the chocolate composition, an additional dispersed phase is introduced, which can influence the microstructure and cause a change in appearance - colour, texture, melting and rheological properties of the product. In addition, some studies suggest the possibility of an interaction between probiotic microorganisms and polyphenol components in food containing them, which may lead to a change of its antioxidant capacity. In order to establish the extent to which the incorporation of probiotics affect the dominant characteristics of different types of chocolate, an examination of their sensory, antioxidant and rheological properties was carried out immediately after production (0-30 days) and during storage of 90, ie 180 days. With the aim of determination of all factors that may affect the functionality of chocolate with probiotics, the analysis of used packaging materials, which included testing of physical-mechanical and barrier properties, were also conducted. In particular, the freeze-dried probiotic strains Lactobacillus acidophilus NCFM® and Bifidobacterium lactis HN019, as well as DUOLAC MIX L3 - microencapsulated mixture of three probiotic cultures: Lactobacillus acidophilus, Streptococcus thermophilus and Bifidobacterium breve, were added into chocolates of different composition (milk, dark with 44% and dark with 75% cocoa solids)...

Prehrambeni proizvodi koji sadrže probiotske mikroorganizme, uglavnom bakterije mlečne kiseline, sa pozitivnim učincima po zdravlje, predstavljaju jedno od najvećih tržišta funkcionalne hrane, među kojima su proizvodi od mleka najdostupniji. Težnja da korisne, probiotske bakterije bezbednije i lakše prežive uslove gastrointestinalnog trakta, kao i potreba da budu dostupne tokom dužeg vremenskog perioda u odnosu na onaj koji je ograničen trajnošću proizvoda od mleka, nametnula je ideju da se obave opsežnija ispitivanja primene probiotika na čokoladi kao nosaču. Program istraživanja u okviru ove doktorske disertacije bio je usmeren na ispitivanje mogućnosti primene probiotika u različite vrste čokolada, zbog njihove osetljivosti prema velikom broju procesnih faktora i uslovima okoline, a imajući u vidu da je održivost esencijalno svojstvo koje uslovljava njihovu efikasnost. Inkluzijom probiotskih kultura uvodi se dodatna disperzna faza u sastav čokolada, što može imati uticaja na njihovu mikrostrukturu i usloviti promene izgleda - boje, teskture, topivosti i reoloških svojstava. Pored navedenog, pojedina istraživanja ukazuju na mogućnost postojanja interakcija između probiotskih mikroorganizama i polifenolnih komponenata namirnice u koje su dodati, što može dovesti do promene njenog antioksidativnog kapaciteta. Kako bi se ustanovilo u kojoj meri je inkorporiranje probiotika uticalo na dominantna svojstva različitih vrsta čokolada, obavljeno je ispitivanje njihovih senzornih, antioksidativnih i reoloških karakteristika neposredno nakon proizvodnje (0-30 dana) i tokom skladištenja od 90, odnosno 180 dana. Radi utvrđivanja svih faktora koji mogu uticati na funcionalnost čokolada sa probioticima obavljene su i analize upotrebljenih ambalažnih materijala, koje su obuhvatale ispitivanje fizičkomehaničkih i barijernih svojstava...