Temperature and Baking Duration Changes the Physicochemical Properties, Dietary Fiber Content and InVitro Calcium Bioavailability of Spirulina platensis

Abstract

Spirulina platensis is considered as a good source of calcium as it has high calcium content. Calcium in spirulina is found attached to sulphated polysaccharide with ionic bond. Fortification of bakery products with spirulina as a functional food have been developed. Processing food using baking method was  favoured and preferred by consumers. During baking, calcium and other minerals may change its form due to the interaction with other components in food resulting to the change of its solubility. Consequently, it can affect the bioavailability of calcium. This study aims to determine the changes of physicochemical properties during baking  and the calcium bioavailaibility during processing  in a baking system simulation models. S. platensis was added with deionized water (1: 1.5 w/v) forming the mixture with cookies dough-like consistency. Dough was stamped, and heated in various temperature (120, 150 and 180 °C) and duration (10, 20 and 30 minutes).  The results showed that temperature and duration of baking affect the physicochemical properties of the product, which decreased the moisture content, calcium solubility, water holding capacity (WHC) and oil holding capacity (OHC) (p <0.05) as well as the retention of the minerals calcium, magnesium and phosphorus in the product (p <0.05). The solubility of calcium during  baking were 3.24 to 10.21 mg Ca /100 ml, wherein the calcium that could pass through the dialysis membrane  ranged from 0.04 to 0.71 mgCa/100 ml. Invitro calcium bioavailability of S. platensis was influenced by the temperature and baking duration.

Keywords: Spirulina platensis, Calcium, Bioavailability, Temperature, Baking, Dietary fiber