Effect of Addition of Cocoa Shell and Different Hydrocolloids on Properties of Instant Cocoa Beverages

Cilj ovog diplomskog rada bio je ispitati utjecaj dodataka kakaove ljuske, različitih hidrokoloda i postupaka sušenja na svojstva instant kakao napitaka. Kakaova ljuska za proizvodnju je dobivena tako da se odvojila od kakaovog zrna nakon prženja, samljevena je te se nakon mljevenja prosijavanjem izdvojila frakcija manja od 71 μm koja se koristila u proizvodnji. Instant prahovi su se proizvodili aglomeracijom i sušenjem (liofilizacija i sušenje u sušioniku pri 40 °C). Kakaova ljuska se dodavala u udjelima od 0, 5, 10 i 15 %. Hidrokoloidi koji su korišteni u proizvodnji su guar guma, ksantan guma i guma arabika. Nakon proizvodnje instant prahova odredila se vlažljivost, boja, specifični volumen, nasipna gustoća i udio ukupnih polifenola prema modificiranoj Folin-Ciocalteu metodi. Rezultati su pokazali da se povećanjem udjela kakaove ljuske u instant kakao napitcima vrijeme vlaženja povećavalo, a boja prahova sušenih u sušioniku je bila svjetlija u usporedbi s uzorcima sušenim u liofilizatoru. Ukupna promjena boje uzoraka sa ksantan gumom je rasla kod sušenih uzoraka, a padala kod liofiliziranih uzoraka u odnosu na porast udjela kakaove ljuske. Nasipna gustoća praha bila je veća kod uzoraka s većim udjelom ljuske te su dobiveni rezultati pokazali da su nasipna gustoća i specifični volumen obrnuto proporcionalni. Udio ukupnih polifenola se smanjio kod uzoraka s većim udjelom kakaove ljuske.The aim of this thesis was to examine the influence of cocoa shell addition, different hydrocolloids and types of drying on the properties of instant cocoa beverages. The cocoa shell for production was obtained by separating it from the cocoa bean after roasting, after that shell was ground and fractions smaller than 71 μm were separated by sieving and used in the production. Instant powders were produced by agglomeration and drying (frezze-drying and drying in an oven at 40 °C). Cocoa shell was added in proportions of 0, 5, 10 and 15%. Hydrocolloids used in the production were guar gum, xanthan gum and gum arabic. After the production of instant powders, the wettability, color, specific volume, bulk density and content of total polyphenols (by the modified Folin-Ciocalteu method) were determined. By increasing the proportion of cocoa shell in instant cocoa beverages, the wettability decreased, the color of the powder dried in the oven got lighter compared to samples dried in freeze-dryer. The total color change in the samples with xanthan gum increased in the oven dried samples and decreased in the freeze-dried samples. The bulk density of the powder was higher in the samples with a higher shell content and the results showed that the bulk density and the specific volume were inversely proportional. The proportion of total polyphenols decreased in samples with a higher proportion of cocoa shell