Determination of calcium, phosphorous, iron, and potassium in gabi and its starch

• Main Author: Felipe, Doris G.
• Format: text
• Language: English
• Published: Animo Repository 1988
• Subjects: Root crops; Starch crops; Starch; Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/2968
• Institution: De La Salle University

This study aimed to extract starch from two varieties of taro : namely, San Fernando gabi (Alocasia hemorphylla) and gabi Tagalog (Colocasia esculenta). It was found out that gabi San Fernando contains a considerable amount of starch. Gabi Tagalog contains a smaller amount of starch due to its strong binding fibers. The starch and as in samples were analyzed for their calcium content using the atomic absorption spectrophotometric method. To the samples and standard solutions, added were 6,000 ppm Mg and 2% v/v H2SO4 to overcome aluminum, phosphorus, and silicate interferences. Results showed that the San Fernando samples contain a higher concentration of calcium than the gabi Tagalog samples. The UV-VIS spectrophotometric method was used in the determination of phosphorus, in the form of PO43- , which was reacted with (NH4) 2MoO4 and further reduced using hydroquinone. The results obtained suggest that the San Fernando samples contain a greater amount of phosphorus than the gabi Tagalog samples. An atomic absorption spectrophotometer was also used in the determination of iron in gabi. Results showed that both varieties of taro contain almost the same amount of iron. In the determination of potassium, the flame emission technique was utilized by setting the Varian AA-275 Spectrophotometer at an emission mode. Two different wavelength were selected for this analysis, that is, 766.5 and 769.9 nm. To both samples and standards, 1,000 ppm sr was added. From the results obtained, potassium is found to be present at high concentrations in the as is portion of both varieties of gabi. While the potassium content in the starch portion of gabi Tagalog is much higher that the starch portion of Gabi San Fernando.