engleski

BAKING AND STEAMING AS A PRETREATMENT FOR PRODUCTION OF HIGH VALUE SWEET POTATO FLOUR: INFLUENCE ON PHYSICOCHEMICAL PROPERTIES

The sweet potato [Ipomoea batatas (L.) Lam.] is one of the most widely consumed tubers in many cuisines. The estimated production of sweet potato (SP) in Croatia in 2016 was 500 t of which 350 t makes first class, which goes on market in fresh state. The other 150 t makes a good raw material for processing of SP into stable forms such as chips, flour, or starch. Flour produced from SP has the potential for making a variety of food products such as baked goods (bread, cakes, cookies, biscuits) ; doughnuts, breakfast foods (instant porridge, crisp, flake-type products) ; noodles or pasta-type products ; sauces (soy sauce, ketchup) ; and brewing adjuncts. In this study, we investigated the impact of pretreatment (baking and steaming) on physicochemical properties of flours produced from two varieties (orange and purple) by freeze drying. Pretreatments caused decrease in starch, sucrose, glucose and fructose amounts increasing the amount of maltose. Decrease in starch content and increasing the amount of maltose was also evident in increment of soluble solids. Results also showed that pretreatments, baking and steaming significantly decrease β-carotene (105.84 ; 127.72 µg/mL, respectively) in orange, and anthocyanin (0.69 ; 0.57 µg/mL, respectively) content in purple SP compared to untreated SP, 284.65 and 0.89 µg/mL, respectively. Baking and steaming decreased color intensity of SP. However, flour produced from pretreated SP had a higher content of soluble solids, β-carotene and anthocyanins compared to the flour produced from untreated SP. The highest quality flour was produced from baked purple SP.

Sweet potato flour, β-carotene, anthocyanins, freeze drying

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